Bulletin .' <- ^a^ H-^^ vJt-t-'7 a.tri.x*a.l T ( T 31 HATUML HISTORY SURVn FEB 8r:: The Genera of Nearctic Tberevidae Iael E. Irwin i^ Lyneborg IHE LIBRARY OF THE JAil^8xi2 UNIVERSITY OF ILLINOIS AT UR"'"'"'-'^'^'"*''^*'^''' >F ILLINOIS lf>IS INSTITUTE OF NATURAL RESOURCES klJRAL HISTORY SURVEY DIVISION li\APAIGN, ILLINOIS VOLUME 32, ARTICLE 3 NOVEMBER 1980 DATE OF ISSO;^ JAl.'UA.lY 22, 155 us ISSN 0073-4918 . ^'a.tui:a«l History SvLi^-vey The Genera of Nearctic Therevidae liihael E. Irwin IJ Lyneborg fOF ILLINOIS OIS INSTITUTE OF NATURAL RESOURCES ^rURAL HISTORY SURVEY DIVISION hVMPAIGN, ILLINOIS VOLUME 32, ARTICLE 3 NOVEMBER 1980 DATE OF ISSUE JANUARY 22, 1981 «TATF OF ILLINOIS ILLINOIS INSTITUTE OF NATURAL RESOURCES STATE OF ILLINOIS. NATURAL RESOURCES AND CONSERVATION w ,„. F Frank Beal M S C/,." manTTHOMAS Pabk, Ph.D.. Biology: H. S. Gutowskv Ph.D Chcmutry: Wal™ E. TWsoN m'S En£;r.««rins- LoRiN I. Nevling, Jr., Ph.D., ForeHry; L. L. Sloss Ph.D., Gf^^f : W. L. f™R'?r ' EEPhD «"/!?"""•"? 'A-^ President of the University of Illinois; John C. Guvon, Ph.J senling\he President ol Sonlhern Illinois Vmvers _ „ '^ ^. _,.._.•_., ^. ..•_.._ James E. Appleby, Ph.D., Entomologist Edward J. Armbrust, Ph.D., Entomologist Marcos Kooan, Ph.D., Entomologist Ronald H. Meyer, Ph.D., Entomologist Stevenson Moore, III, Ph.D., Entomologist Extension Michael E. Irwin, Ph.D., Associate Entomologist Donald E. Kuhlman, Ph.D., Associate Entomologist, Extension _ ^ . „ ... Joseph V Maddox, Ph.D., Associate Entomologist Robert D. Pausch, Ph.D., Associate Entomologist RoscoE Randell, Ph.D., Associate Entomologist, Extension „ , . ,, . i , William G. Ruesink Ph.D., Associate Entomologist John K. Bouseman, M.S., Assistant Entomologist Catherine Eastman, Ph.D., Assistant Entomologist Allan Felsot, Ph.D., Assistant Entomologist Eli Levine, Ph.D., Assistant Entomologist , - " , Ph.D., Assistant Entomologist ,'M.S., Assistant Specialist, Extension M.S., Assistant Entomologist, , Assistant Specialist, Kathabyn Ewing, B.S., Technical Assistant Dwight Carrels. B.S., Technical Assistant Becky Grosser, B.S., Technical Assistant Jeff Hutton, B.S., Technical Assistant Jeanine Kasprowicz, B.S., Technical Assistant Diane Lynn, B.S., Technical Assistant Philip Mankin. B.S.. Technical Assistant Steve Miller, B.S., Technical Assistant Aleta Parker. B.S., Technical Assistant Sue Peratt, Technical Assistant Steve Pescitelli, B.S.. Technical Assistant Mike Retzer. M.A., Technical Assistant Nancy Rue, Technical Assistant Sherri Sandberg, B.S.. Technical Assistant Jens Sandberger, M.S.. Technical Assistant Michael Sandusky, B.S., Technical Assistant Yip Tai Sa-NG, B.S., Technical Assistant Steve Sobaski, B.S., Technical Assistant Charles Stone, B.S.. Technical Assistant John J. Suloway, B.S., Technical Assistant Sam Sum, B.S., Technical Assistant Pam Tazik, M.S., Technical Assistcint Jeffrey v.an Ormann. B.S.. Technical Assistant Gary L. Warren, B.S., Technical Assistant Mark J. Wetzel. B.S., Technical Assistant Ruth Wagner, Junior Technical Assistant Section of Faunistic Surveys and Insect Identification Wallace E. LaBerge, Ph.D., Insect Taxonomist and Head Larry M. Page. Ph.D.. Taxonomist George L. Godfrey, Ph.D., Associate Taxonomist John D. Unzicker. Ph.D.. Associate Taxonomist Donald W. Webb. M.S.. Associate Taxonomist David J. Voectlin. Ph.D.. AssulanI Taxonomist Bernice P. Sweeney. Junior Professional Scientist Eugene Miliczky. M.S.. Research Assistant Section of Wildlife Research Glen C. Sanderson, Ph.D.. Wildlife Specialist and Head Frank C. Bellrose. Sc.D.. Wildlife Specialist William R. Edwards. Ph.D.. Upland Wildlife Ecologisi Tean W. Grabfr. Ph.D.. Ornilholosist Richard R Grabfr, Ph.D., Ornllholoeist Harold C. Hanson. Ph.D.. WlldlUr Specialist Wiliiam L. Anderson. M.S.. Wildlife Eeologisl W W. Cochran, Jr.. B.S., Associate Wildlife SpfciaUst Charles M. Nixon, M.S.. Porest Wildlife Ecoloeist Ronald L. Westemeier, M.S., Grassland Wildlife Ecnlogist Tonnie'P. Hansen, Ph.D., Forest Wildlife Ecologisi Stephen P. Ha\t.ra, Ph.D., Wildlife Ecologisi Ronald P. Larkin, Ph.D.. Wildlife Ecologisi Richard E. Warner, M.S., Wildlife Ecologist Suzanne G. Wood, Ph.D.. Assistant Chemist John E. Buhnerknepe, M.S.. Assistant Supportive Scientist , . , „ . . Robert D. Crompton, Junior Professional Scientist Ronald E. Duzan. lunlor Professional Scientist Cynthia Jackson. B.S.. Junior Professional Scientist T\MES W. Seets, Junior Professional Scientist Eva Stecer, B.S.. hinior Professional Scientist ToHN S. LoHSE. Ph.D.. Research Assistant H. Kathleen Archer. B.S.. Technical Assistant Iames Cheisvio. B.S.. Technical Assistant Kmz.\beth .\. McConaha, Technical Assistant Teresa A. Overton. B.S.. Technical Assistant .Alan Pfj!K1NS, M.S., Technical Aisittant Supporting Services Phyllis Ciark, Supply Room Manager WiLMA G. Dillman, Properly Control and Trust Accounts Patty L. Duzan, Payroll and Pertonnel Robert O. Ellis. Assistant for Operations T,\RRV D. Gross. Olicralions Assistant T. William Lusk. Mailing and Distribution Senicrs Chris Rohl. Operations Assistant Melvin E. Schwartz, Fiscal Officer Publications and Public Relations Robert M. Zewadski. M.S.. Technical Editor Shirley McClellan. B.S.. Assistant Technical Editor I.10YD LeMfrf. Technical lllutlralor Lf.slie Woodrum. Technical Photographer Technical library Doris L. Sublette, ^LS.L.S., Technical Librarian Monica Lusk, Library Clerk linix^.i r>, . .^....^.^ Sysstematic Entomology, Roderick R. lR\vi>r Chicago. m'n.;.; W.'ldliVe Research."- Willard D. Klimstra, Ph.D., Professor ';' Z""'"£'^ "^^ "''''i,'";,."'/^"?''/;;;;;;^ Wildlife Research. Southern Illinois Vniiersily: Parasitology. Norman D Levine. Ph.D.. Profysor "'''"" nay Parasitology Veterinary Research and Zo«/..cv and pireelor of the Center for "'''""" f-;;"'^):JZohJ^ "f Illinois: Entomology. Robert L. Mftcmf. Ph.D.. P'ofe^nr of Biology and Research P'"I"_"'±^"'"'",T^\ Unii-er^ity of Illinois: and Gilbert P. Waldbauer. Ph.D., Professor n/ Enlnmolo^. f '"•""'• "'/'''"''"• Statistics Horace W. Norton, Ph.D., Professor o Statistical Design and Analysis. Vniversity of Illinois. Luis R. Zavaleta, Arthur Agnello, David A. Gentry, Extension Charles MacMonegle, M.S., Extension „ . ,. r, - • Kevin Steffey, Ph.D^ Assistant Specialist, Extension Steven Troester, M.E., Assistant Systems Engineer Jean G. Wilson, B.A., Supervisory Assistant Lester Wei, Ph.D., Assistant Professional Scientist Charles G. Helm, M.S., Assistant Supportive Scientist William Lamp, Ph.D., Assistant Supportive Scientist Stephen Roberts, B.S., Assistant Supportive Scientist John T. Shaw, B.S., Assistant Supportive Scieritist Daniel Sherrod, M.S., Assistant Supportive Scientist Sue M. Hale, Junior Professional Scientist Gerald A, Schultz, Ph.D., Research Associate Michael Jeffords, Ph.D., Field Entomologist Robert J. Barney B.S., Research Assistant Michael Burke, M.S., Research Assistant Tzu-SuAN Chu, M.S., Research Assistant Jenny Kooan. M.S., Research Assistant Susan Post, B.S., Research Assistant , Gail Kampmeier, M.S., Research Technician Michael McGuire, M.S., Research Technician Jo Ann Auble, Technical Assistant Ellen Brewer, M.S., Computer Programmer Howard Ojalvo, M.S., Computer Programmer Section of Botany and Plant Pathology Glaus Grunw,vld, Ph.D., Botanist and Head Eugene Himelick, Ph.D.,P;on( Pathologist Dan Neely. Ph.D., Plant Pathologist D F. Schoeneweiss, Ph.D., Plant Pathologist I. Leland Crane, Ph.D.. Mycologist Anton G. Endress, Ph.D., Associate Botanist Kenneth R. Robertson, Ph,D,. Associate Botanist Betty Nelson, Assistant Supportive Scientist Gene E Reid, Junior Professional Scientist Iames E. Sergent, Greenhouse Superintendent Robert A, Harrison. Technical Assistant David R. Moore, B.S., Technical Assistant Section of Aquatic Biology „. , . . u j Robert W. Gorden, Ph.D., Aquatic Biologist and Head D Homer Buck, Ph.D., Aquatic Biologist William F. Childers, Ph.D., Aquatic Biologist R Wfldon Larimore, Ph.D., Aquatic Biologist Robert C. Hiltibr.an, Ph.D.. Biochemist Richard F. Sparks, Ph.D., Aquatic Biologist Keturah Reinbold, Ph.D., Associate Aquatic Biologist John Tranquilli, Ph.D., Associate Aquatic Biologist Ken Lubinski, Ph.D.. Assistant Aquatic Biologist David P. Philipp, Ph.D.. Assistant Aquatic Ihologist Henry H. Seagle, Jr., Ph,D., Assistant Aquatic Biologist .«!•. Ted W Storck, Ph.D., Assistant Aquatic Biologist Bruce Taubert, Ph.D., Assistant Aquatic Biologist Michael Wiley. Ph.D., Assistant Aquatic Biologist Richard I. Baur. M.S.. Assistant Supporjiie Scientist Eugene Sons, Junior Professional Scientist Tana L, Waite, M.S.. Junior Professional Scientist Stephen W. Waite, M.S., Research Associate Dale Burkett, B.S.. Research Assistant Larry W. Coutant, M.S.. Research Assistant Christine Kaminski, B.S.. Research Assistant Dennis Newman. M.S.. Research Assistant L\nce Perry, M,S.. Research Assistant Todd Powless, M.S.. Research Assistant Mike Reese, M.S.. Research Assistant Thomas Skelly. M.S.. Research Assistant Sarah Storck, M,S., Research Assistant Jerry Broughton, B.S., Technical Assistant Chri'stine Clark, B,S., Technical Astistant CONSULTANTS AND RESEARCH AFFILIATES: -->• WAT T\ . ._ 1tr-...»^ 1~\ L' t fe d f^ -rn A CONTENTS Acknowledgments 194 Abbreviations Used in Descriptions and Figures 194 Family Therevidae 195 Description of Adult 195 Key to the Genera of Nearctic Therevidae 201 Subfamily Therevinae 203 Dialineura Rondani 204 Pallicephala Irwin & Lyneborg 206 Viriliricta Irwin & Lyneborg 208 Dichoglena Irw'm & Lyneborg 210 Pandivirilia Irwin & Lyneborg 212 Spiriverpa Invin & Lyneborg 214 Thereva Latreille 216 Tabiidaniima Irwin & Lyneborg 219 Tabuda Walker 221 Acrosathe Irwin & Lyneborg 223 Psilocephala Zetterstedt 225 Penniverpa Irwin & Lyneborg 227 Lynlinga Irwin & Lyneborg 230 Brachylinga Irwin & Lyneborg 232 Litolinga Irwin c& Lyneborg 234 Rhagioforma Irwin & Lyneborg 236 Arenigena Irwin & Lyneborg 238 Arnmonaios Irwin & Lyneborg 240 Megalingii Irwin & Lyneborg 242 Megalinga insignata Irwin & Lyneborg 244 Breviperna Irwin 247 Nebrkus Coquillett 249 Cyclotelus Walker 251 Ozodiceromya Bigot 254 Chromolepida Cole 258 Subfamily Phycinae 260 Phycus Walker 260 Henicomyia Coquillett 262 Parapherocera Irwin 264 Pherocera Cole 266 Schlingeria Irwin 268 Unplaced Species of Therevidae 270 Literature Cited 271 Index 274 This report is printed by authority of the State of Illinois. It is a contnbution from the Section of Economic Entomology of the Illinois Natural History Survey. Michael E. Irwin is Associate Professor of agricultural entomology. Office of Agricultural Entomology; Associate Professor of plant pathology. Department of Plant Pathology; and Researcher in the International Soybean Program, Office of International Agriculture, all at the University of Illinois. He is also an Associate Entomologist, Section of Economic Entomology, Illinois Natural History Survey. Leif Lyneborg is Entomologist and Curator of Diptera, Uni- versity Zoological Museum, Copenhagen. The Office of Agricultural Entomology, Department of Plant Pathology, Office of Inter- national Agriculture , Illinois Agricultural Experiment Station, and the Illinois Natural History Survey provide equal opportunities in programs and employment. (48940—IM— 11-80) Fig. 1. — Tbereva frontalis Say adult female. The Genera of Nearctic Therevidae Michael E. Irwin and Leif Lyneborg The first description of a North American therevid was of Bibio ab- dominalis from the West Indies (Fabri- cius 1805). Next, descriptions of Nearc- tic Therevidae were pubHshed by a European, C. R. W. Wiedemann (1821, 1824, and 1828), and an American, Thomas Say (1823, 1824, and 1829). Further descriptions followed thereafter by Macquart (1840), Walker (1848, 1850, 1852, and 1857), Rondani (1856), Bellardi (1861), Loew (1869a, 1869&, 1872, 1874, and 1876), Osten Sacken (1877 and 1887), Williston (1886), and Bigot (1889). The turn of the century nbrought a few new American dipterists ;into the picture (Johnson 1902 and :1926; Adams 1903 and 1904), but by ifar the most important therevid worker iof that time was D. W. Goquillett, who iipublished revisionary monographs of the Therevidae (1893a and 18936) and iadded greatly to the concepts within the Ifamily (1894, 1898, 1904a, 1904&, and M910). Following Goquillett, Otto Krober 111 Germany became the reigning world authority on the Therevidae, and he added considerably to the number of de- scribed species in North America through revisions and new descriptions (1911, 1012, 1914, 1928a, 19286, and 1929). In 1923 Frank Gole (1923a) published a monographic revision of the Therevidae of North America. This work has re- mained the definitive treatment for the jarea for the past 57 years. American workers, including Gole (19236, 1925, II959, 1960a, and 19606), Hardy (1938 and 1943), James (1936 and 1949), James & Huckett (1952), and Bromley ,(1937), added occasional new descrip- 'tions and names to the slowly growing list of Therevidae of North America. In the late 1960's and 1970's, we became active in the area of therevid systematics. Lyneborg (1972) revised the Xestomyza group of Therevidae, including the genus Hcnicomyia from the Western Hemisphere, and Irwin (1977a and 19776) revised three genera of North American Therevidae. During the course of preparing the Therevidae chapter for the soon-to-be- published Manual of Nearctic Diptera (Ganada Department of Agriculture 1981), v\'e found that the previously pub- lished descriptions of genera were totally inadequate to form a framework for the therevid species of North America. The genus Psilocephala Zett., for instance, was found to be polyphyletic, containing species from several diverse ancestors. An effort to describe the many new genera contained herein was begun be- cause we realized the definitive nature of the forthcoming Manual oj Nearctic Dip- tera and the importance of establishing a generic base for the Therevidae founded on synapomoi"phies. We have restrained ourselves from grouping the genera be- yond the subfamilial level simply because we feel that better natural groupings can be formed once genera from other parts of the world are included in the scheme. We have attempted to place the de- scribed species in the new generic con- cepts at the end of each diagnosis. All North American genera are diagnosed, and male terminalia are figured for all genera. In total, 29 genera and 143 cur- rently valid species have been described for North America, excluding A psilo- cephala Krober (1914) and its included species, longistyla Krober (1914), which we feel does not belong within the family Therevidae. We have not included Melanothereva MaWoch (1932:249) that occurs in Chile, Peru, and parts of Ar- gentina and contains a single Nearctic species, nigra (Bellardi) [1861:92, S 193 194 Illinois Natural History Survey Bulletin Vol. 32. Art. 3 (Psilocephala)] that, to our knowledge, has not been rediscovered since it was first described from Mexico. The descriptions and keys follow morphological terminology developed by us. Male terminalia characters were originally defined and described by Lyne- borg (1968a) and have since been modi- fied slightly by Lyneborg (1972, 1976, and 1978) and by Irwin (1977(z and 19776). Female terminalia characters were defined and described by Irwin ( 1976) . Other morphological features are generally accepted in Diptera literature, and we refrain from detailing them here. The immature stages of Therevidae have not been used in developing this preliminary classification. Larval and pupal stadia are being gathered and as- sociated with adults in the hope that eventually they will help to elucidate the proper phylogenetic placement of species within genera and genera within supra- generic taxa. ACKNOWLEDGMENTS We wish to express our deep gratitude to Herbert J. Teskey, Canadian National Collection, and Donald W. Webb, Illi- nois Natural History Survey, for review- ing the manuscript. We also vkdsh to thank John P. Sherrod for drawing the frontispiece, the late Kai L. Elsman and Robert Nielsen for illustrating the paper, and Sandy McGary for typing the manu- script. Robert M. Zewadski, Technical Editor of the Illinois Natural History Survey, edited the final version for pub- lication. This publication would not have been possible without the loan of material from nearly all of the major entomologi- cal collections in North America and the loan of type material from the United States National Museum of Natural His- tory, the Canadian National Collection, the Philadelphia Academy of Natural Sciences, the California Academy of Sci- ences, the California Insect Survey (Berkeley), the American Museum of Natural History, Cornell University, the British Museum of Natural History, Mar- I tin Luther University (Halle), Natur- historisches Museum (Vienna) , Zoological Museum ( Copenhagen ) , and others. To ' the curators who made these specimens available, we owe a great debt of grati- tude. We especially acknowledge the help and encouragement of the curators from the University of California at Riverside, Saul I. Frommer; the University of Cali- fornia at Davis, Robert O. Schuster ; and the University of California at Berkeley, Evert I. Schlinger. We wish to thank these organizations for supporting in part the cost of this paper: Office of Agricultural Entomol- ogy, Office of International Agriculture, and the International Soybean Program, University of Illinois; and the Illinois Natural History Survey. Special thanks are due those who en- couraged the production of this paper. They include Dr. William H. Luckmann, Evert I. Schlinger, Frank R. Cole, the systematists in the Section of Faunistic Surveys and Insect Identification of the Illinois Natural History Sur^,ey, the dipterists at the Canadian National Col- lection, and our wives, Bonnie and Crete, who gave unselfishly of their patience • and understanding. To all of these we express heartfelt gratitude. ABBREVIATIONS USED IN DESCRIPTIONS AND FIGURES ad: anterodorsal ae: aedeagus av: anteroventral c: cerci dap : dorsal apodeme dc : dorsocentral dp: distiphallus eap : ejaculatory apodeme ep: epandrium fi : fore femur fa : middle femur fs : hind femur gc: gonocoxite gs: gonostylus h: hypandrium np: notopleural pa: postalar pap : parameral apodeme I Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 195 pd: posterodorsal pp : parameral process pv: posteroventral sa; supra-alar scutellar fore tibia middle tibia hind tibia vap : ventral apodeme veps : ventral epandrial sclerite vl : ventral lobe FAMILY THEREVIDAE Description of Adult Slender to moderately thick-bodied flies (Fig. 1) ; length, excluding anten- nae, 2.5-15 mm. Background color light yellow to black. Body wholly or partly pilose, tomentose, pruinose, or some com- bination of these characters; setae usually prominent. Head.— Hemispherical, not depressed at vertex, hypognathous to prognathous. Eyes dichoptic in female, holoptic in most males, usually without hairs in both se.xes. Frons of female wide, reaching o( cllar tubercle, often covered variously with pollen and scattered hairs; frons of male usually small, acutely to broadly triangular, tomentose to bare, often with- out hairs. Three prominent ocelli set at Ncrtex or slightly anterior of vertex. An- tenna three segmented, sometimes set on prominent frontal protuberance; scape variously setose; pedicel usually with a ring or two of short setae; first flagello- mere without setae, or with setae usually confined to basal third ; flagellar style comprises 1 or 2 flagellomeres and a terminal or subterminal spine set apically or subapically on apical flagellomere ; spine elongate and prominent in some genera, but almost undetectable in others. Face often tomentose ; lateral areas pilose or not; genae pilose or not, often with a darkened tomentose or bare stripe; oc- ciput finely tomentose, often densely pilose from midpoint ventrally and prom- inently setose dorsally; postocular setae usually present though often slender. Palps one or two segmented, usually pi- lose and not prominent, set beside pro- boscis in subcranial cavity; proboscis slightly longer than palps, usually carried within subci-anial cavity. Thorax.— Scutum varies from nearly square to elongately rectangular when viewed from above, often sparsely to densely tomentose or pilose or both. Scutellum prominent, often without pile, but almost always tomentose. Pleuron variously pilose; upper portion usually densely tomentose; lower portion some- times without pollen. One pair postalar setae; 1-6 pairs notopleural setae or more; 1 or 2 pairs supra-alar setae; usu- ally 0-2 pairs dorsocentral setae, but 3 or more in a few species; 0-3, rarely 4, pairs scutellar setae. Wing. — Venation remarkably uni- form (Fig. 32) ; Ri setose or not; R4 elongate, usually S-shaped ; cell d has mi, m2, nis arising from apex; CuAi does not meet posterior margin of cell d ; crossvein m-cu present; cell cu-p closed behind; cell m3 open or closed; abnormalities common in wing venation. Stigma usu- ally well-developed. Wing hyaline to in- fuscate, sometimes banded or spotted, veins often surrounded by darker infus- cation. Microtrichia from sparse to dense. Calypter well-developed. Halter large and well-developed. Legs. — Usually fairly long and slen- der; hind legs longer than others. Fore coxa (Fig. 3) with none to several setae on anterior surface; middle co.xa with (Fig. 4) or without (Fig. 5) pile on posterior surface; all femora bare to heavily setose, especially anteroventrally, often with long scalelike pile along dorsal surface; tibiae and tarsi setulose in defi- nite longitudinal rows; fore tibia lacks setae anteroventrally. Five tarsomeres present; first tarsomere longest and some- times swollen; claw with 2 pulvilli and a setalike central empodium or without empodium. Abdomen.— Usually convex to flat- tened dorsally and tapering at apex, sometimes laterally compressed, always with 8 well-developed pregenital seg- ments. Fine silveiy pollen often adorns 196 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 abdomen, covering it completely in male of many species and in patterns on fe- male. Tomentum and pile present or absent, usually longer and denser on male. Female Terminalia. — Characterized by large conspicuous sternite 8, func- tioning variously as a digging-anchoring apparatus for oviposition, a floor for genital chamber, and a guide for penial insertion during copulation (Invin 1976). Stemite 9 (furca), acting as roof of genital chamber, completely internal, with 2 lateral sclerites fused posteriorly Fig. 2-7. 2. — NebWtus pethcidus Coq. male head in dorsal view. 3. — Megallnga insignata Irw. & Lyn. fore coxae, prosternum, and cervical lobes. 4. — Palticephala voriegoto (Lw.) middle coxa. 5. — Orodiceromyo mexicono Big. middle coxo. 6.— Tobuda varia (Wlk.) head in lateral view. 7.— Dorso- frontal view. Scale: 1 mm. Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 197 to a sclerotized bar that contains a mem- glands. Three unsclerotized spermathecae branous central sheath through which and 2 accessory glands present. Tergite pass ducts of spermathecae and accessory 8 generally unmodified. Tergite 9 usually Fig. 8-15. 8.— Thereva plebeja (I.) female head in frontal view. 9. — Antenna. 10. — Psilocephata Tunda Lw. female head in frontal view. 11. — Antenna. 12. — Pandivirilia limata (Coq.) hind femur in /entral view. 13. — Virilirlda monfivaga (Coq.) hind femora in ventral view. 14. — Pandivirilia limata Coq.) male head in frontal view. 15. — Dichogtena amplifrons (Cole) male head in frontal view. Scale; l).5 mm for 9 and 11, 1 mm for others. 198 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 a single sclerite, generally with extended lateral margins fused to posterolateral margins of furca. Tergite 10 always di- vided though often fused with tergite 9; digging-anchoring spines often present posterodorsally and anterolaterally al- though reduced in Phycinae. Sternites 10 and 11 (hypoproct or subanal plate) generally a single plate, usually heavily sclerotized though more thinly so in some genera of Phycinae. Cerci disc shaped, attached to tergite 10 in most groujjs, but fused into a single sclerite in Pherocera, Parapherocera, and Schlingeria. Male Terminalia (Fig. 107-114).- Fairly uniform in plan. .Sclerites forming sternite 8 and tergite 8 unmodified to narrowly constricted medially. Tergite Fig. 16-25. 16. — ti"fo//nga acuta (Adams) female head in lateral view. 17. — Frontal view. 18. — Brachy/ingo faaccalo (Coq.) female head in frontal view. 19. — Arenigena semilaria (Coq.) male head in frontal view. 20. — Ammonaios niyeus (Krob.) male head in frontol view. 21. — Arenigena semitorio (Coq.) antenna. 22. — Ammonoios niveus (Krob.) antenna, 23. — Rhogioformo macu/ipennis (Krob.) antenna. 24.— Cyclotelus rufivenlris (Lw.) female fore tarsus. 25.— Penniverpo festino (Coq.) female fore tarsus. Scale; 0.5 mm for 21-23, 1 mm for others. Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 199 9, the epandrium, acting as a large cover- and shapes; bears ventral epandrial ing for terminalia, variously haired, often sclerite and cerci apically. Stemite 9, the with posterolateral lobes of various sizes hypandrium, large in some genera, nar- Fig. 26-32. 26. — Cyc(o*e/us pruinosus Wlk. antenna. 27. — Cyclofe/us rufivenfri's (Lw.) antenna. 128. — Ozodiceromya mexicana Big. antenna. 29. — Ozodiceromyo signalipennis (Cole) antenna. 30. — Cyclofe/us rufiventrh (Lw.) female head in frontal view. 31. — Chromo/epida bel/a Cole male tiead in lateral view. 32. — Pandivirilia limata (Coq.) wing. Scale: 1.3 mm for 26, 0.5 mm for 27-29, 1 mm for 30, ond 0.7 mm for 31. 200 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 Fig. 33-41. 33.— Pbycus brunneus (Wlk.) male head in anterodorsal view. 34. — Phycus hrunneut (Wlk.) palp. 35. — Henicomyia hubbardii Coq. male head in lateral view. 36. — Antenna of an un- named species of Phycvs from southern California. 37. — Paropherocero montono Irw. antenna. 38. — Pherocera sp. antenna. 39. — Schlingeria ammobata Irw. antenna. 40. — Paropherocero montono Iwr. mole head in frontal view. 41. — -Pherocera sp. mole head in frontal view. Scale: 0.5 mm for 34 and 36-39; 1 mm for 33, 35, 40, and 41. row to absent in others, variously free from or fused to gonocoxites. Gcnocox- ites fused or free ventrally. Each gono- coxite often extends posteriorly as a broad to narrow lobe well beyond in- sertion of gonostylus, usually with one or more additional appendages. These appendages include ventromedially a ventral lobe that appears to function as an aedeagal guide and dorsally a para- mere (= dorsal gonoco.xal process). Paramere composed of ( 1 ) a rod-shaped apodeme most anteriorly on gonocoxite and in some groups with a connecting sclerotized bridge to aedeagus, (2) a midsection closely fused with doreal edge of gonocoxite, and (3) a free distal por- tion, the parameral process, usually shaped as a style beaiing setae apically, but entirely absent in many genera. Gonostylus variously shaped, moving in a dorsoventral or oblique direction and not opposed, seemingly lying within genital cavity of female during copula- tion. Aedeagus consists of a short to long variously twisted distiphallus, an elongate Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 201 or vestigial dorsal apodeme, a simple or forked ventral apodeme sometimes hav- ing 2 extensions toward tip of distiphal- lus, and a variously shaped ejaculatory apodeme. Aedeagus attached at one or more of three sites, (1) by anterior edge of intersegmental membrane below epandrium (usually as a basal extension of ventral epandrial sclerite) to distal margin of dorsal apodome, (2) by para- meral apodeme to dorsolateral portion of aedeagus, or (3) by ventral lobe to mid- ventral section of aedeagus. KEY TO THE GENERA OF NEARCTIC THEREVIDAE 1. Middle coxa with pile on posterior surface (Fig. 4) 2 Middle coxa without pile on posterior surface or with only a few appresscd scalelike hairs (Fig. 5) 20 2. Prosternum with pile in and around central depression (Fig. 3) 3 Prosternum without pile in and around central depression 15 3. Lower frons in both sexes entirely shiny; head strongly protruding an- teriorly: compound eyes of male sep- arated by more than width of ocellar tubercle (Fig. 2) Nebritus Coquillett (p. 249) Lower frons at least partially to- mentose; head not strongly protrud- ing anteriorly; compound eyes sepa- rated at most by width of ocellar tubercle 4 4. Lateral portion of face, at least upper part, without pile 5 Lateral portion of face, at least upper part, with pile 13 5. Paired cervical lobes anterior to presternum, each with a strong black seta in addition to whitish pile (Fig. 3). Veins R2+3 and Ri have a deep curve before wing margin. Distiphal- lus deeply cleft at apex (Fig. 164) . . . .Megalinga Irwin & Lyneborg (p. 242) Paired cervical lobes anterior to prosternum without a strong black seta, with only whitish pile present. Vein R2*3 usually has a gentle curve before wing margin. Distiphallus not cleft 6 6. Macrosctae of mcsonotum all pale. Paramcral process present, enlarged, and modified distally (Fig. 149 and 156). Cell ma closed . . .Arenigena Irwin & Lyneborg (p. 238) Macrosetae of mesonotum usually all black; if macrosetae pale (some Ly- silinga), then cell ms open. Parameral process absent or present and simple. Cell m3 only rarely closed 7 7. Scape in lateral view distinctly wider than first flagellomere (Fig. 54 and 55); pile of scape long and dense. ... 8 Scape in lateral view narrower than or as wide as first flagellomere (Fig. 21-23); pile of scape short and sparse 9 8. Male frons has pile. Lower part of fe- male frons has pile. Fore and middle femora without setae. Epandrium (Fig. 42 and 43) has posterolateral corners only slightly projecting and not extending to distal margin of cerci and ventral epandrial sclerite; the latter often greatly enlarged. Hypandrium absent (Fig. 44) Dialineura Rondani (p. 204) Male frons without pile. Lower part of female frons without pile. Fore and/or middle femora usually have some short setae. Epandrium (Fig. 48 and 49) has posterolateral corners strongly projecting, extending to or beyond distal margin of cerci and ventral epandrial sclerite. Hypan- drium (Fig. 50) present as a small narrow transverse sclerite between anteroventral margins of gonocoxites. . Pallicephala Irwin & Lyneborg (p. 206) 9. One pair of scutellar setae and genal area (Fig. 16) have darkened wedge or stripe; ocellar tubercle very promi- nent, especially in male . . .Litolinga Irwin & Lyneborg (p. 234) Two pairs of scutellar setae or genal area not darker than lower portion of occiput, uniform in color and texture; ocellar tubercle normal 10 10. Palps constricted a short distance before apex. Wing strongly maculated. Male frons prominent, with long, dense, black pile. Female abdomen yellow- ish brown with median row of dark spots Rhagioforma Irwin & Lyneborg (p. 236) Palps not constricted apically. Wing not strongly maculated. Male frons with or without long, dense pile. Fe- male abdomen variously colored, usu- ally brownish to grayish, without median row of dark spots 11 I 1 . Pile of fore femur pale and erect, composed of long, uniform, thin hairs. Parameral process large, free; gono- stylus simple, slender (Fig. 66 and 67) ....•...._ . . . . Pandivirilia Ij-win & Lyneborg, in part (p. 212) 202 Illinois Natural History Survey Bulletin Vol. 32. Art. 3 Pile of fore femur composed of ap- pressed whitish, scaly hairs and slen- der, erect hairs that are whitish or blackish. Paramere without a distal portion; gonostylus hook-shaped, bear- ing groups of setae (Fig. 122, 129, and 130) 12 12. Dorsocentral setae absent. Abdomen orange to reddish brown in both sexes. Aedeagus (Fig. 122) about half as long as gonocoxite; distal section of distiphallus subapical, projecting down- ward (Fig. 125) . . .Lysilinga Irwin & Lyneborg (p. 230) One or two pairs of dorsocentral setae present. Abdomen gray or black. Aedeagus (Fig. 129) usually more than half as long as gonocoxite; distal section of distiphallus apical (Fig. 133) Brachylinga Irwin & Lyneborg (p. 232) 13. Frons (Fig. 20) in both sexes has dense, appressed pile of whitish, scaly hairs. Macrosetae of mesonotum pale. A circular blackish area usually pres- ent in and aroimd each anterior ten- torial pit Ammonaios Irwin & Lyneborg (p. 240) Frons in both sexes has pile of erect, normal hairs. Macrosetae of mesono- tum black. Area in and around an- terior tentorial pits not differently colored from rest of face 14 14. Male has epandrium as long as or longer in midline than wide (Fig. 103); aedeagus has ventral projec- tions adjoining distiphallus (Fig. 104). Male abdomen covered entirely by whitish pile. Female frons has pat- tern formed by dull pale or dark col- ored tomentum, without subshiny to shiny calli . . .Acrosathe Irwin & Lyneborg (p. 223) Male epandrium much shorter in mid- line than wide (Fig. 81); aedeagus without ventral projections adjoining distiphallus (Fig. 83). Male abdomen covered entirely by whitish pile only in a few species. Female frons (Fig. 8) in most species has callus or calli that are large, shiny, black or at least subshiny medially Thereva Latreille (p. 216) 15. Scape (Fig. 6) distinctly longer and wider than first flagcllomcre. Head protruding anteriorly 16 Scape not longer or wider than first flagellomere. Head not strongly pro- truding anteriorly 17 16. Male has compound eyes (Fig. 7) sep- arated by at least width of anterior ocellus. Two supra-alar setae and 1 dorsocentral seta present. Cell m3 broadly open. Parameral process knob- like (Fig. 96) . . .Tabuda Walker (p. 221) Male has compound eyes separated by less than width of anterior ocellus. One supra-alar seta present; dorsocen- tral setae absent. Cell ma closed or nar- rowly open. Parameral process extends beyond level of gonocoxite (Fig. 88) Tabudamima Irwin & Lyneborg (p. 219) j 17. Mesonotal pile of male short, sparse, and appressed; hairs shorter than width of scape. Hind femur (Fig. 13) has sparse, appressed pile and many short, scattered, black setae on entire ventral surface in addition to normal row of strong, anterovcntral setae. . . . . .Viriliricta Irivin & L\Tieborg (p. 208) Mesonotal pile of male long, abundant, erect; hairs distinctly longer than width of scape. Hind femur (Fig 12) has denser, usually erect pile and at most a few short, black, posteroventral setae apically in addition to usual row of strong anterovcntral setae 18 18. Male compound eyes (Fig. 15) sep- arated by at least width of anterior ocellus. Female has black or blackish brown tibiae. Female has tergite 4 en- tirely shiny black Dichoglena Irwin & Lyneborg (p. 210) Male compound eyes (Fig. 14) sepa- rated by less than half width of ante- rior ocellus. Female has yellowish brown tibiae. Female has tergite 4 at least partly tomentose 19 19. Lower frons of both sexes has whitish pile; upper, lateral portion of face with long, whitish pile. Hypandrium (Fig. 73) present; distiphallus long, its tip twisted (Fig. 75) . .Spiriverpa Irwin & Lyneborg (p. 214) Lower frons of both sexes either with- out pile or with blackish pile; upper, lateral portion of face in most species without pile, but if pile present, then black. Hypandrium (Fig. 66) absent: distiphallus short, its tip not twisted (Fig. 68) Pandivirilia Invin & Lyneborg, in part (p. 212) 20. Prosternum has pile in and around central depression (Fig. 3) 21 Prosternum without pile in and around central depression 24 21. A pair of shiny, black, raised calli on upper face below antennal bases (Fig. 31). Thorax and abdomen clothed with totally appressed, broad scales in addition to normal pile. . . . Chromolepida Cole (p. 258) Face without shiny calli. Pile of thorax and abdomen composed of semi-ap- prcssed, scaly hairs and erect, normal hairs 22 Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 203 Cell mj broadly open. Male frons en- tirely tomentose and without pile; fe- male frons entirely tomentose. Fore tibia has at most 2 or 3 very short posteroventral setae; fore tibia and first tarsomere very slender (Fig. 25) . .Penniverpa Irwin & Lyneborg (p. 227) Cell ma closed or narrowly open (in some Breviperna). Male frons usually partly shining and with pile; female frons variously shining (not in Brevi- perna). Fore tibia has several stout posteroventral setae; fore tibia and first tarsomere stout (Fig. 24) 23 Entire frons in both sexes covered with tomentum, without shiny areas. Male dichoptic. Large, broadly built species with short broad antennae Breviperna Irwin (p. 247) Frons in both sexes at least partly shiny. Small and slenderly built spe- cies, with slender antennae (Fig. 28 and 29) . . .Ozodiceromya Bigot (p. 254) Hind femur has appresscd, scaly hairs, usually also some anteroventral setae. Tergite 10 of female heavily spinose; distal spines stout, short, projecting dorsally and laterally; basal spines slim, long, projecting ventrally 25 Hind femur has erect, normal hairs, without anteroventral setae. Tergite 10 of female slenderly spinose; spines of only one kind. PHYCINAE 26 First tarsomere of foreleg swollen (Fig. 24). Scutellum short, with pile on margin only; katepisternum with- out pile. Male terminalia partly tele- scoped and concealed within abdomen, usually yellowish. Parameral process absent (Fig. 182) Cyclotelus Walker (p. 251) First tarsomere of foreleg not swollen. Scutellum long, with long pile on disc; katepisternum has long, pale pile. Male terminalia prominently project- ing, polished black; parameral process large, prominently extends beyond gonocoxite (Fig. 107) Psilocephala Zctterstcdt (p. 225) !6. Scutellar setae absent 27 One pair scutellar setae present 28 One or two notopleural setae present; mesopleuron without pile. First flagel- lomere much longer than scape (Fig. 35). Middle and hind tarsi have very short setae. Genital opening of female directed dorsally Henicomyia Coquillctt (p. 262) Three notopleural setae; mesopleuron has long pile. First flagellomere only slightly longer than scape (Fig. 39). Middle and hind tarsi have very long, thin setae. Genital opening of female posteriorly directed Schlingeria Irwin (p. 268) 28. Palps distinctly two segmented, with apical segment shorter (Fig. 34). Hind femur has very short, uniform hairs. Cerci of male project posteriorly be- yond ventral epandrial sclerite (Fig. 204). Antenna distinctly longer than depth of head (Fig. 33) Phycus Walker (p. 260) Palps one segmented. Hind femur has elongate hairs. Cerci and ventral epandrial sclerite of male project the same distance posteriorly. Antenna shorter than or about as long as depth of head 29 29. Antenna at least as long as depth of head; shining, raised callus present between antennal base and subcranial cavity (Fig. 40); male dichoptic... Parapherocera Irwin (p. 264) Antenna shorter than depth of head; no raised callus between antennal base and subcranial cavity; male holoptic (Fig. 41) (except for a single unde- scribed species from Mexico) Pherocera Cole (p. 266) Subfamily Therevinae These attributes characterize the North American members of the subfamily Therevinae. 1. Usually without a strong sclerotized bridge between dorsal apodeme of aedeagus and paramere; if such a bridge is present {Cyclotelus, some Ozodiceromya) , hypandrium unde- tectable. 2. Ventral apodeme of aedeagus not forked and not vestigial, projects an- teriorly as a simple sclerite. 3. Tergite 10 of female has a group of thickened spines (acanthophorites) set in posterodorsal and posterolateral po- sitions and a second group of thinner, often longer spines set lateroventrally on tergite 9; tergite 9 fused with ter- gite 10. 4. Intersegmental membrane between sternite 8 and stemite 9 (furca) of fe- male sclerotized. 5. Pregenital abdominal segments have spiracles in the pleural membrane. 6. Vein Ri not setose. 204 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 Genus Dialineura Rondani (Fig. 42-47) Dialineura Rondani 1856: 155. Type-spe- cies: Musca anilis Linnaeus 1761:442 by original designation. Type-locality: Sweden. Reference: Lyneborg 1968fc. Diagnosis Small- to medium-sized, moderately slender species. Head. •— Frons of male at its narrow- est narrower than half width of anterior ocellus; frons of female at level of an- terior ocellus 2.0-2.5 X as wide as ocellar tubercle; male frons entirely tomentose with long pile over most of its surface; female frons entirely and uniformly to- mentose, sometimes with a dull, dark, transverse band over middle, with to- mentum of lower frons sometimes paler than that of upper frons; female frons has short, rather sparse pile over most of its surface; head markedly protruding anteriorly, antennae thus set on a dis- tinct protuberance; a dark, dull band at antennal level apparent in certain views, I I i Fig 42-47. — Diol.neuro onilis (L.) mole terminolla. 42. — GenitoUo in lateral view. 43. — Epandrium with appendages in dorsal view. 44. — Right gonocoxite with appendages and aedeagus m dorsal view. 45. — Aedeogus in lateral view. 46. — Slernite 8. 47. — Tergite 8. Scale: 0.5 mm. Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 205 but facial and genal calli absent; lateral jX)rtion of face usually bare, only pilose in affinis Lyneborg (1968t: 157 3 ) from China; gena has long, pale pile; depth of head 1. 1-1.3 X length of antennae; scape 1.0-1.3 X as long as flagellum, thickened; flagellar style apical and two segmented, with a small terminal spine; palps one segmented. Thorax. — np 2-4 (usually 3), sa 2, pa 1, dc 1-3; sc 2; mesonotal pile in male long, uniform, erect, pale, with a few black hairs intermixed; mesonotal pile in female of two types: in the first, moderately long, sparse, erect, black and in the other short, rather dense, semi-ap- pressed, pale; prosternum has long, pale pile in and around central depression. Wing. — Cell m^ open; veins Ri and Rr, of equal length; cell Vi 2. 1-2.4X as long as wide at apex; color hyaline with faint grayish or brownish tinge; stigma pale brownish to dark brownish. Legs. — Fore coxa has 2-4 apical setae on anterior surface; middle coxa has long pile on posterior surface; hind femur has 6-10 anteroventral setae. Abdomen. — Slender to moderately broad, gradually tapering from segment 3 onward; abdomen not telescoped; dorsum somewhat flattened in female, more convex in male; male dorsum cov- ered entirely by silvery gray tomentum and whitish pile; female dorsum exten- sively tomentose, some species having distinct, dark, shining, anterior bands. Male Terminalia (Fig. 42-47). — Tergite 8 (Fig. 47) rather large and markedly constricted medially; stemite 8 (Fig. 46) comparatively large, bilobed (i.e., has a deep V- or U-shaped incision in posterior margin) ; epandrium (Fig. 143) longer medially than wide, in most species more markedly narrowing poster- iorly than in the type-species and has a distinct, lateral incision (Lyneborg 1968a) ; cerci free (Fig. 43), well sclero- tized, never extending beyond ventral epandrial sclerite; ventral epandrial sclerite varies greatly in size, in the type- species (Fig. 43) not extending beyond cerci, but in other species from moder- ately (e.g., in gorodkovi) to noticeably extending beyond cerci, being longer than half length of epandrium; ventral epan- drial membrane weak, reaching to near anterior margin of epandrium, but not attached to anterior margin of aedeagus ; parameral apodeme not attached to aedeagus; distiphallus (Fig. 44) in dorsal view comparatively long and wide, some- times provided with small spines; in lateral view, distiphallus (Fig. 45) sud- denly downcurved with extreme apex upcurved; dorsal apodeme 2-4X as wide as distiphallus base, often with 2 tooth- shaped outshoots dorsally, its distal mar- gin has a semicircular incision; ventral apodeme large, usually extending beyond dorsal apodeme and narrowly spoon shaped; ejaculatory apodeme simple, slightly thickened both proximally and distally; ventral lobes of gonocoxite long, slender, lamellate, directed obliquely up- ward and loosely attached to midventral surface of aedeagus; parameral process short, narrow, reaching far short of posterior apex of gonocoxite and rarely visible in lateral view (Fig. 42) ; para- meral apodeme short and narrow; some species show an additional small, finger- like process on inner side of gonocoxite slightly distad of parameral process in- sertion (Lyneborg 1975: Fig. 2); gono- coxites not united ventrally except by a weak membrane; gonocoxite (Fig. 42) in lateral view characteristically projects and gradually narrows posteriorly; hy- pandrium totally absent. Habitat The habitat of the North American species is totally unknown. Distribution The one species recorded from the Nearctic Region has been found only in Manitoba, Canada. Several described species occur throughout the Palearctic Region. Included Species gorodkovi Zaitzev 1971:191 $, 9. Distribution.— Fort Churchill, Man- itoba, Canada; also Siberia in Asia. 206 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 No undescribed specimens are known Feminine to us. Derivation of name: palla (Greek) = Genus Pallicephala Irwin & Lyneborg, ball; kephale (Greek) = head. new genus (Fig. 4 and 48-55) Type-species: Psilocephala variegata Fig. 48-55. — Pollicephala spp. 48-53. — P. willisloni (Cole) male lerminalla. 48. — Genilolia in lateral view. 49. — Epondrium with appendages in dorsal view. 50. — Right gonocoxite with appendages and aedeagus in dorsal view. 51. — Aedeagus in lateral view. 52. — Sternite 8. 53. — Tergite 8. 54.— Antenna of P. voriegofo (Lw.). 55. — Antenna of P. wiliistoni [Cole). Scale: 0.5 mm. Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 207 Loew 1869^:170 by present designa- tion. Type-locality: "Canada" (prob- ably eastern Canada) . Diagnosis Moderate to large-sized, slender to heavy-bodied species. Head. — Frons of male at its narrow- est narrower than half width of anterior ocellus; frons of female at level of an- terior ocellus 2.2-2.5 X as wide as ocellar tubercle; male frons entirely tomentose, uniformly colored, and without pile; fe- male frons entirely tomentose, either uni- formly colored or upper part darker than lower part, or has a pair of dark, velvety spots; pile of female frons restricted to upper two-thirds and in most species short and sparse; head rather promi- nently protrudes anteriorly; a dull, dark- ened band crosses frons at antennal level, but facial and genal calH absent; lateral portion of face without pile ; genae have long pile; head 1.1-1.5X deeper than antennal length (Fig. 54 and 55) ; scape 0.8-1.2 X as long as flagellum, thickened in most species; flagellar style apical, stout, two segmented, with a small, ter- minal spine; palps one segmented. Thorax.— np 3-5, sa 1-2, pa 1, dc 1- 4, sc 1-2; mesonotal pile in most species short, pale, and semi-erect to appressed, but short, black, erect pile also occurs, and willistoni has long pile composed of black and white hairs; prosternum has long, pale pile in and around central depression. Wing.— Cell va^ open (ex- cept in variegata) ; vein R4 distinctly longer than vein R5; cell r4 1.9-2.5 X as long as wide at apex; color hyaline with faint grayish-brown tinge, some- times maculated ; most species have a distinct, brown stigma. Legs. — Fore coxa has 2-3 pale or black, ventrally di- rected setae close to apical margin; these setae are slender in most species, but stout in willistoni; middle coxa has pile nn posterior surface (Fig. 4) ; hind femur with 2-10 anterovcntral setae. Abdomen. — Moderately broad to broad, gradually tapering from base to apex; abdomen not telescoped: dorsum of male convex, of female more flattened ; dorsum of male entirely tomentose or has blackish anterior bands on anterior ter- gites; dorsum of female has blackish an- terior bands, with posterior parts of ter- gites tomentose. Male Terminalia (Fig. 48-53). — Tergite 8 (Fig. 53) small and only mod- erately constricted medially; sternite 8 (Fig. 52) small, often without a distinct incision; epandrium (Fig. 49) shorter or slightly longer in midline than wide, posterolateral corners greatly project and broadly rounded, extending be- yond cerci and ventral epandrial scler- ite; cerci free (Fig. 49), well sclerotized, not extended beyond ventral epandrial sclerite; ventral epandrial sclerite sclero- tized only as a bilobed area below cerci; membrane below epandrium reduced to 2 narrowly triangular sections posteriorly; parameral apodeme not attached to aedeagus; distiphallus (Fig. 50) in dorsal view short compared with dorsal apo- deme, seen laterally (Fig. 51) suddenly downcurved; ventral apodeme forms a short spoon; ejaculatory apodeme short and simple; ventral lobes of gonocoxites directed upward, lamellate, narrowing distally, and have an attachment to ventral surface of aedeagus; parameral process large, extending beyond posterior margin of gonocoxite; gonocoxites not fused ventrally, but attached for a long distance by a membrane; gonocoxite in lateral view (Fig. 48) shows a process posteroventrally ; hypandrium well de- veloped, free (Fig. 50). Habitat Nothing is known of the habitats that species of this genus occupy except for willistoni, often found in oak grasslands along dry or nearly dry stream beds. Distribution Species in the genus Palliccphala are largely found in western North America ; one species is found in the Great Lakes region of North America. Included Species flavipilosa (Cole) 1923a:62 $, 9 (Psilocephala as a subspecies of var- 208 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 iegata Loew), new combination. Distribution. — Central California. fuscipennis (Cole) 1923a:62 9 {Psilo- cephala), new combination. Distri- bution.— Washington. occidentalis (Cole) 1923a: 61 $ {Psi- locephala as a subspecies of variegata Loew) , new combination. Distribu- tion. —• Oregon. variegata {'Loe^N) 1869b: 170 5 {Psilo- cephala), new combination. Distri- bution. — Great Lakes region of North America. willistoni (Cole) 1965:352 {Diali- neura) , new combination. Distribu- tion. — Pacific northwest southward to San Francisco Bay and Santa Cruz County, California. crassicornis Y^Wliston 1886:293 5, ? {Thereva) , not Bellardi 1861:88. No undescribed species of this genus are at hand. Genus Viriliricta Irwin & Lyneborg, new genus (Fig. 13 and 56-60) Feminine Derivation of name: virilia (Latin) ~ male genitals; rictus (Latin) = open, gaped. Type-species: Psilocephala montivaga Coquillett 18936:226 by present desig- nation. Type-locality: Los Angeles County, California. Diagnosis Large though rather slender flies. Head. — Frons of male at its narrow- est at least as wide as width of anterior ocellus; frons of female narrow, at level of anterior ocellus 1.3-1.8X as wide as ocellar tubercle; male frons dull to sub- shiny, usually extensively darkened over most of its area, silver-gray to whitish tomentum usually restricted to lower, lateral parts; upper male frons has lateral rows of short, black, semi-appressed hairs (a few hairs may occur on lower frons) ; female frons extensively tomentose or subshiny black, tomentum dark, with richer, but shorter pile than that of male ; head moderately to greatly protruding anteriorly; facial and genal calli absent; lateral portion of face without pile; gena has a few short hairs; head depth 1.2- 1.4X antennal length; flagellum slender, 1.4-1.7 X as long as scape; scape slender: flagellar style apical, two segmented, with a minute terminal spine; palps one seg- mented. Thorax.— np 4-5, sa 2, pa 1, dc 1-2, sc 2; mesonotal pile of both sexes short, sparse and semi-appressed, not longer than width of scape; prostemum bare in and around central depression. Wing.— Cell ma open; vein R4 distinctly longer than vein R5; cell r^ 2.7-3.0X as long as wide at apex; color hyaline with grayish to brownish tinge; stigma distinct. Legs. — Fore coxa has 2-3 apical setae on anterior surface; middle coxa has sparse, short, whitish pile on posterior surface; hind femur (Fig. 13) has sparse, ap- pressed pile, especially at base, 5-7 an- teroventral setae, many additional, short, scattered, black setae on ventral surface; fore and middle femora usually have ventral setae in similar position. Abdomen. — Male abdomen distinct; rather wide, short, tapering from base to apex (in montivaga) ; in other species longer, more slender, and nearly equally wide throughout; dorsum always dis- tinctly convex ; male dorsum may be en- tirely tomentose or may have a pattern of shiny black and tomentose areas; fe- male dorsum shiny brownish to blackish with tomentose areas laterally on first few- segments. Male Terminalia (Fig. 56-60). — Tergite 8 (Fig. 60) comparatively large and strongly constricted medially; ster- nite 8 (Fig. 59) also rather large, more or less distinctly incised along posterior margin; epandrium (Fig. 58) about as long at midline as wide, with large, broadly rounded posterolateral corners: cerci free, well sclerotized, not projecting beyond ventral epandrial sclerite; ventral epandrial sclerite large, reaching or nearly reaching anterior margin of epandrium, without distinct attachment to anterior Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 209 Fig. 56—60. — Viriliricta montivaga (Coq.) male ierminalia. 56.— Right gonocoxite with appendages and oedeagus in dorsal view. 57.— Aedeagus in lateral view. 58. — Epandrium with appendages in dorsal view. 59. — Sternite 8. 60. — Tergite 8. Scale: 0.5 mm. margin of aedeagus; ventral epandrial sclerite rather well sclerotized, especially fKisteriorly, where it is pointed and keel shaped, and diverges from cerci ; para- meral apodeme without attachment to aedeagus; distiphallus in dorsal view gradually tapering, in lateral view posi- tioned in same plane as longitudinal axis of aedeagus (Fig. 57) ; dorsal apodeme large, rectangular; ventral apodeme long, slender; ejaculatory apodeme extends slightly anteriorly beyond dorsal apo- deme; ventral lobes of gonocoxites mod- erately large, rounded and directed toward and loosely attached to ventral surface of aedeagus; ventral lobes not attached ventrally along midline; para- meral process protrudes prominently be- yond level of posterior margin of gono- coxite; parameral apodeme moderately long and slender; gonocoxites not united ventrally (Fig. 66) even by a membrane; gonocoxites in lateral view short and truncate posteriorly; hypandrium absent. Habitat Little is known about the habitat of these species. An adult of V. montivaga 210 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 was captured while resting on a leaf of a bush near a stream. All species seem to inhabit mountainous areas. Distribution Two species exist in the mountains of eastern North America and a third in western North America. Included Species canadensis (Cole) 1923(z:57 ? {Psilo- cephala) , new combination. Distri- bution.— Ontario, Canada. This species may prove to be conspecific with grandis (Johnson) . grandis (Johnson) 1902:24 5 {Psiloce- phala) , new combination. Distribu- tion. — Quebec, Canada, and New York. montivaga (Coquillett) 1893fc:226 $, $ {Psilocephala) , new combination. Distribution. — Mountains of Cali- fornia, Nevada, Arizona, and Utah. One undescribed species from Ten- nessee is at hand. Genus Dichoglena Irwin & Lyneborg, new genus (Fig. 15 and 61-65) Feminine Derivation of name: dicha (Greek) = in two parts; glene (Greek) = eyeball. Type-species: Psilocephala amplifrons Cole 1925:85 by present designation. Type-locality: New York, West Danby. This species was erected as latifrons Cole 1923a: 73 not latifrons Frey 1921: 82 [Aristothereva] . Diagnosis Medium- to large-sized flies from some- what slender to slightly broad. Head. — Frons of male (Fig. 15) at its narrowest distinctly wider than, and up to twice as wide as, width of anterior ocellus; frons of female narrow, at level of anterior ocellus only 1.4— 1.5 X as wide as ocellar tubercle; male frons in frontal view dull brownish to blackish, in dorsal view shows silver gray tomentum, with sparse but rather long, black pile laterally on upper and/or lower part ; female frons subshiny to shiny black or brown nearly overall, or on upper half only; pile denser than in male; head only slightly pro- trudes anteriorly; facial and genal calli absent; lateral portion of face bare; gena has short, stiff pile which may extend to lower face; head depth 1.2-1 .3X length of antennae; scape slender, 0.5-0.6X as long as flagellum; flagellar style apical, two segmented, with a minute terminal spine; palps one segmented. Thorax. — np 3-4, sa 2, pa 1. dc 0-2, sc 2; mesonotal pile of male long, erect, uniform, whitish ; hairs much longer than width of scape; mesonotal pile of female much shorter, semi-appressed, black ; pro- sternum bare in and around central de- pression. Wing. — Cell nis open; vein Ri longer than vein Rj; cell Tt 2. 1-2.5X as long as wide at apex; color hyaline with grayish brown tinge; stigma dis- tinct. Legs.— Fore coxa has 2 or 3 apical setae on anterior surface; middle coxa has whitish pile on posterior sur- face; hind femur has 4—5 anteroventral setae. Abdomen. — Slender, only slightly tapering from base to apex, and not telescoped ; dorsum convex to rather flat- tened; male dorsum entirely covered by silver gray tomentum and by whitish pile; female dorsum extensively shiny to sub- shiny blackish, with small areas of to- mentum on posterolateral comers of ter- gites 2-3 and 5-6 ; tergite 4 entirely shiny (cf. Viriliricta, Pandivirilia, and Spiri- verpa). Male Termin.a^lia (Fig. 61-65). — Tergite 8 (Fig. 64) comparatively very large, wider than epandrium. moderately constricted in middle; sternite 8 (Fig. 65) also large, only indistinctly incised posteriorly; epandrium (Fig. 63) shorter in midline than wide; posterolateral cor- ners of epandrium greatly projecting: cerci free, well sclerotized, do not project beyond ventral epandrial sclerite; ventral epandrial sclerite well sclerotized overall, short, tapering anteriorly, far short of reaching anterior margin of epandrium; parameral apodeme without attachment to aedeagus; distiphallus in dorsal view (Fig. 61) narrow and short compared Nov., 1980 Irwin & Lyneborg: The Genera OF Nearctic Therevidae 211 _ 65 Fig. 61—65.— Dicboghna amplifrons (Cole) male terminalia. 61. — Right gonocoxite with appendages and aedeagus in dorsal view. 62. — Aedeagus in lateral view. 63. — Epandrium with appendages in dorsal view. 64. — Tergite 8. 65. — Sternite 8. Scale: 0.5 mm. with rest of aedeagus, suddenly down- curved, terminating in a long, S-curved tube (Fig. 62) ; in caudal view straight; dorsal apodeme rectangular; ventral apodeme narrow and longer than dorsal apodeme; ejaculatory apodeme flat in lateral view, greatly enlarged distally in dorsal view; ventral lobes of gonocoxites large, rounded, directed obliquely up- ward and backward, with a strong at- tachment to ventral surface of aedeagus ; parameral process slender, prominently protruding beyond posterior margin of gonocoxites; parameral apodeme rather long and narrow; gonocoxites (Fig. 67) not united ventrally, but touch for a long distance; gonocoxite in lateral view truncate with lower, posterior comer pro- jecting; hypandrium present as a band- shaped sclerite firmly attached to gono- I coxites (Fig. 61). 1 Habitat Nothing is known of the habitat oc- cupied by adults or larvae of species in this genus. All specimens examined were apparently collected in forested areas. Distribution Members of this genus are found in the western, central, northeastern, and eastern portions of the United States (California, Colorado, Vermont, Massa- chusetts, Connecticut, New York, New Jersey, Pennsylvania, North Carolina, South Carolina, Florida, Illinois, and Kansas) and in eastern Canada (On- tario) . Included Species amplifrons (Cole) 1925:85 3 (Psilo- cephala), new combination. Distri- bution.— Southeastern Canada and northeastern to eastern USA. latifrons (Cole) 1923a: 73 $ {Psilo- ccphala), not Frey 1921:82 [Aris- tothcreva) . borealis (Cole) 1923a: 126 9 {The- reva) , new combination. Distribu- tion.— Michigan, northern Illinois. 212 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 melampodia (Loew) 1869a:9 9 {Psilo- cephala), new combination. Distri- bution. — Central to southeastern USA. nigrina (Krober) 1914:53 9 [Psilo- cephala), new combination. Distri- bution. — Florissant, Colorado. A few undescribed species fit within the boundaries of this genus; these are from western North America. Genus Pandivirilia Irwin & Lyneborg, new genus (Fig. 12, 14, 32, and 66-71) Neuter, but as adjective takes feminine form. Derivation of name: pando (Latin) = lay open; virilia (Latin) = male geni- tals. Type-species: Psilocephala limata Co- quillett 1894:99 by present designa- tion. Type-locahty : Colorado and Washington. Diagnosis Head.— Frons of male (Fig. 14) at its narrowest distinctly narrower than width of anterior ocellus ; frons of female narrow, at level of anterior ocellus 1.5- 1.8 X as wide as ocellar tubercle; male frons usually has silver gray to whitish tomentum, in a few species tomentum somewhat darker above; frons without pile, or with dark pile on lateral, lower part only; female frons darker on upper half than lower half, either caused by brownish tomentum or because upper frons distinctly subshiny to shiny brown- ish black to black overall, never foiTning bare, polished calli, since upper darkened frons has distinct, black pile; head mod- erately protrudes anteriorly; facial and genal calli absent; lateral portion of face and gena without pile or pile sparse and restricted to lower face and gena; head depth 1.4-1.8X antennal length; scape slender, 0.5-0.8X as long as flagellum: flagellar style apical, two segmented, with a small terminal spine; palps one segmented. Thorax.— np 3-6, sa 2, pa 1, dc 1-2. sc 2 ; mesonotal pile of male long, erect. uniform, sometimes composed of both pale and dark hairs; pile distinctly longer than width of scape; mesonotal pile of female shorter and more appressed; prostemum bare in and around central depression. Wing (Fig. 32). — Cell ma open; vein Rj longer than, or at least as long as, vein R5; cell Ti 2.0-2.5 X as long as wide at apex ; color hyaline, often with a grayish or brownish tinge; stigma usu- ally distinct. Legs. — Fore coxa has 1-3 apical setae on anterior surface; middle coxa with long, whitish pile on posterior surface; hind femur (Fig. 12) has 5-8 anteroventral setae and usually a few short posteroventral setae near apex. Abdomen.— Rather slender, gradu- ally tapering from base to apex, not tele- scoped ; dorsum convex to rather flat- tened; male dorsum with silver-gray to whitish tomentum and exclusively whit- ish pile; female dorsum has broad, shiny, blackish, anterior bands on anterior seg- ments. Male Terminalia (Fig. 66-71). — Tergite 8 (Fig. 70) small and greatly constricted medially; stemite 8 (Fig. 71) small, bilobate, with deep, V-shaped in- cision on posterior margin ; epandrium (Fig. 69) from nearly as long along mid- line as to distinctly longer along midline than wide, with prominently projecting posterolateral corners and with a deep incision in posterior margin; cerci free, well sclerotized, do not project beyond ventral epandrial sclerite; ventral epan- drial sclerite large, reaching to anterior margin of epandrium, with or without a weak, membranous attachment to an- terior margin of aedeagus; ventral epan- drial sclerite largely membranous, only a small area below cerci sclerotized ; para- meral apodeme without attachment to aedeagus; distiphallus in dorsal view (Fig. 67) short and narrow compared with rest of aedeagus, suddenly down- cuned and slightly S-cuived (Fig. 68), in caudal view straight; dorsal ap)odeme rectangular, arched: ventral apodeme long, equally wide or slightly widening distally; ejaculatoiy apodeme usually Nov., 1980 Irwin & Lyneborg: The Genera of Nearctig Therevidae 213 Fig. 66-71. — Pandivirilia limala (Coq.) male terminalia. 66. — Gonocoxite with appendages and aedeagus in ventral view. 67. — Right gonocoxite with appendages and oedeagus in dorsal view. 68. — Aedeagus in lateral view. 69. — Epandrium with appendages in dorsal view. 70. — Tergite 8. 71. — Sternite 8. Scale: 0.5 mm. slightly extended anteriorly beyond dor- sal apodeme; ventral lobes of gonocoxites large, rounded, directed obliquely up- ward, with a membranous attachment to ventral surface of aedeagus; ventral lobes connected along midline by a membrane; parameral process protrudes prominently beyond level of posterior margin of gono- coxite; parameral apodeme short and narrow; gonocoxites not united ventrally 214 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 (Fig. 66), in lateral view short and trun- cate posteriorly ; hypandrium absent. Habitat Specimens of this genus have been col- lected in forested areas in mountains of western North America. A pupa was col- lected from an old pine log in the San Bernardino Mountains, California. Distribution Most species are from western North America (British Columbia, Washington, Oregon, California, Idaho, Utah, Colo- rado, Montana, Nevada, Arizona) with at least one species from the northern and eastern United States (Wisconsin, New York, Maine) and eastern Canada (Nova Scotia, Ontario). Included Species argentifrons (Cole) 1923a: 56 $ {Psi- locephala) , new combination. Dis- tribution. — Pennsylvania. hussi (James) in James & Huckett 1952:265 S, § {PsUoccphala),new combination. Distribution. — Can- ada (Yukon Territory) southward into northwestern USA (Washing- ton). limata (Coquillett) 1894:99 9 {Psilo- cephala), new combination. Distri- bution. — Western North America. pollinosa (Cole) 1923a: 72 3 [Psilo- cephala), new combination. Distri- bution.— Sierra Nevada Moun- tains, California. Several undescribed species are at hand. Genus Spiriverpa Irwin & Lyneborg, new genus (Fig. 72-79) Feminine Derivation of name: spira (Latin) = twist; verpa (Latin) = penis. Type-species: Thereva luniilata Zetter- stedt 1838:523 by present designation. Type-locality: Norway. Diagnosis Medium-sized, moderately broad spe- cies. Head. — Frons of male at its narrow- est no wider than half width of anterior ocellus; frons of female at level of an- terior ocellus 1.8-2.0X as wide as ocellar tubercle; tomentum on male frons uni- formly whitish silver, or at most indis- tinctly darker on upper lateral part; pile all whitish and long, restricted to lower lateral portion of frons; tomentum on female frons darker on upper half than on lower half; pile blackish above, whit- ish below, shorter and more appressed than in male; head moderately protrudes anteriorly; facial and genal calli absent; lateral portion of face and gena has long, whitish pile; antennae (Fig. 79) 0.7- 0.8X as long as depth of head; scape slender, 0.6-0.7 X as long as flagellum; flagellar style apical, two segmented, with a minute terminal spine; palps one segmented. Thorax. — np 2-4 (usually 3), sa 2- 3 (usually 2), pa 1, dc 1-2 (usually 2), sc 2; mesonotal pile in male dense, uni- form, erect, rather long and whitish; in female two types of pile; one is moder- ately long, scalelike, appressed, whitish, and the other is longer, normal, erect, and blackish; prostemum without pile in and around central depression. Wing. — Cell ma open at wing margin (closed in some males) ; vein Rj longer than vein R5; cell Ti 2. 1-2.3X as long as wide at apex; color grayish hyaline with pale brownish stigma. Legs. — Fore coxa has 2 apical setae on anterior surface; middle coxa has long, \vhitish pile on posterior sur- face; hind femur has 5-7 anteroventral setae. Abdomen.— Rather slender, gradu- ally tapering from anterior margin of segment 3 to apex; abdomen not tele- scoped, rather flattened on dorsum; male dorsum lias silver-grayish tomentum and long, whitish pile; female dorsum has blackish anterior bands on fii-st segments and shorter, partly blackish pile. Male Terminalia (Fig. 72-78). — Tergite 8 (Fig. 77) rather large and greatly constricted medially; stemite 8 (Fig. 78) also large with a wide incision in posterior margin; epandrium (Fig. 76) from nearly as long in midline as to dis- Nov., 1980 Irwin & Lyneborg : The Genera OF Nearctic Therevidae 215 tinctly longer in midline than wide, widi ners forming a deep incision in pos- strongly projecting, posterolateral cor- terior margin; cerci free, well sclero- Fig. 72-79. — Spiriverpa lunulala (Zetl.). 72-78. — Mole lerminalia. 72. — Right gonocoxile with appendages and aedeagus in dorsal view. 73. —• Gonocoxites and hypandrium in ventral view. 74. Aedeagus in lateral view. 75. — Distiphallus in caudal view. 76. — Epandrium with appendages in dorsal view. 77. — Tergile 8. 78. — Sternite 8. 79. — Antenna. Scale: 0.5 mm. 216 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 tized, not projecting beyond ventral epandrial sclerite; ventral epandrial sclerite large, reaching to anterior margin of epandrium, with a membranous at- tachment to anterior margin of aedeagus ; ventral epandrial sclerite largely mem- branous, only portion below cerci well sclerotized; parameral apodeme without attachment to aedeagus; distiphallus (Fig. 74) very long, slender, its apex (Fig. 75) twisted to the right (with re- spect to specimen as a whole) ; dorsal apodeme short, V shaped, continuing into a membrane; ventral apodeme nar- rowly spoon shaped ; ejaculatoiy apodeme flat in lateral view, with a spoon-shaped distal extension in dorsal view; ventral lobes of gonocoxite large and complex, directed upward at an angle of about 45° to longitudinal axis; ventral lobes connected on their ventral surface by a weakly sclerotized membrane; this mem- brane binds the gonocoxites postero- ventrally (Fig. 73) ; a membranous at- tachment also present between ventral lobes and ventral surface of aedeagus; parameral process long, very slender, may or may not reach beyond level of posterior margin of gonocoxite; para- meral apodeme also long and slender; gonocoxites not united ventrally, in lat- eral view obliquely truncate posteriorly; hypandrium (Fig. 73) free, forming a narrow band adjoining anterior margin of gonocoxites. Habitat We do not know the exact habitat of this group of species, but many speci- mens have been collected in the sand dunes along the Great Lakes, especially along the eastern shore of Lake Michi- gan. We suspect that species in this genus inhabit sandy substrates. Distribution Species of the genus Spiriverpa are found along the Atlantic coast from Flor- ida to Vermont, in Ontario and Ne\\' Brunswick, Canada, and throughout tlie New England, Great Lakes, and Midwest states (including Kansas) westward through Colorado to Oregon and north- ward to Alaska, including parts of Canada. Included Species albiceps (Loew) 1869&:166 9 {The- reva) , new combination. Distribu- tion. — Northeastern United States. ?albifrons (Say) 1829:156 $ [The- reva) , new combination. Distribu- tion. — Indiana. bella (Krober) 1914:64 3, 9 [The- reva) , new combination. Distribu- tion. — Northeastern United States. (This species may be conspecific with senex (Walker) .) bella iiigrimana (Krober) 1914:64 3 (Thereva), new combination. Dis- tribution. — Massachusetts. (This subspecies may be the same as bella (Krober).) candidata (Loew) 1869a:8 3 (The- reva), new combination. Distribu- tion. — Eastern North America and westward along the Great Lakes. (This species may be synonymous with senex (Walker) .) cinerascens (Cole) 1923a: 97 9 [The- reva), new combination. Distribu- tion. — Oregon. cockerelli (Cole) 1923a :99 3, 9 [Thereva) , new combination. Distri- bution. — Rocky Mountains, espe- cially Colorado northward into Canada. mYom (Coquillett) 1894:101 9 [The- reva) , new combination. Distribu- tion.— Soutliern portion of mid- westem United States. senex (Walker) 1848:224 $ [The- reva), new combination. Distribu- tion. — Southeastern Canada. There are a few undescribed species i within this genus from \Nestern North f America and one described species from northern Europe. Genus Thereva Latreille (Fig. 8, 9, and 80-87) j Feminine Thereva Latreille 1796:167. Type-spe- cies: Musca plebeja Linnaeus 1758; subsequent monotypy by Latreille Nov., 1980 Irwin & Lyneborg: The Genera of Nearctig Therevidae 217 Fig. 80-87. — Therevo plebeja (L.) male terminalia. 80.— Genitalia in lateral view. 81.— Epandrium iwith appendages in dorsol view. 82. — Epandrium with appendages in ventral view. 83. — Aedeagus in lateral view. 84. — Aedeagus in dorsal view. 85. — Right gonocoxite in ventral view. 86. — Tergite 8. 87.— Sternite 8. Scole: 0.5 mm. ( 1802 : 441 ) . Type-locality : Northwest- em Europe. Thereua, Loew error. Reference: Coquillett 1893a, Cole 1923a. Diagnosis Medium- to large-sized, hca\y-bodied, usually densely pilose species. Head. — Frons of male at its narrow- est much narrower than half width of anterior ocellus; frons of female (Fig. 8) at level of anterior ocellus 2.0-3.OX as wide as ocellar tubercle; frons of female almost always has a pattern formed by differentially colored tomentum and cen- 218 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 tral, shiny callosity (in some species there are two callosities on raised portions of frons) ; frons of male variously tomen- tose and pilose, only rarely with a shining callosity; head of each sex exceptionally wide ; eyes of both sexes have single facet size; long, thin pile over frons (espe- cially lower part above antennae of fe- males), face, and genae of both sexes; gena wide in frontal view; head pro- trudes slightly at level of antennae ; head depth 1.0-1.3 X antennal length (Fig. 9) ; scape 0.8-1.2 X as long as flagellum; flagellar style apical, two segmented, with a short, heavy terminal spine; palps one segmented. Thorax. — np 3-5, sa 1-2, pa 1, dc 0-2, sc 2; mesonotal pile usually long, dense, erect on males; mesonotal pile of two types on female: one is short, erect, usually dark, the other is appressed, bronze colored ; presternum has long pile in and around central depression. Wing. — Cell ms open or closed ; veins R4 and R5 of about equal length; cell T4 about 1.5-2.5 X as long as wide at apex; color variable, from hyaline to heavily mottled, veins in some species surrounded by dark infuscation; stigma usually distinct, light to dark brown. Legs.— Fore coxa with 2-5 (usually 4) apical setae on heavily pilose anterior surface; middle coxa has long pile on anterior and posterior sur- faces ; femora have setae in anteroventral position or setae lacking on fore and/or middle femora. Abdomen. — Moderately broad, taper- ing abruptly toward apex; abdomen not telescoped; dorsum somewhat flattened in female, more convex in male; pattern variable, with tomentum entirely whitish gray (rare) to brownish in definite bands (common) ; abdomen of both sexes pilose, pile usually erect, denser and longer on male. Male Terminalia (Fig. 80-87). — Tergite 8 (Fig. 86) rather variable, large, and greatly constricted medially; sternite 8 (Fig. 87) variable, generally large, rec- tangular shaped, posterior margin often notched; epandrium (Fig. 81 and 82) wider than long along midline, postero- lateral margins not extending posteriorly as far as cerci; cerci free, well sclerotized; ventral epandrial sclerite (Fig. 82) com- posed of a sclerotized midposterior section below cerci and 2 lateral sclerotiza- tions attached by a membrane to postero- lateral margins of epandrium, but not extending anteriorly to base of epan- drium and not strongly connected to aedeagus; aedeagus (Fig. 83 and 84) rather small, simple; parameral apodeme not attached to aedeagus; distiphallus short, slightly downcurved distally, in dorsal view several times wider basally than distally; dorsal apodeme broader and projects anteriorly farther than ven- tral apodeme ; ejaculatory apodeme sim- ple, stick shaped; gonocoxites not united ventrally except by a thin membrane, usually broadly rounded posteriorly, often with a distinct projection; parameral process long, fingerlike, often extending to or beyond level of posterior comer of epandrium; gonostylus (Fig. 85) ^vell de- veloped, long, usually directed posteriorly and dorsally, thicker basally than distally, and hooklike apically; ventral lobe (Fig. 85) long, irregularly shaped, not extend- ing posteriorly to ajiex of gonostylus: by- . pandrium present as a narrow sclerite between ventrobasal part of gonocoxites. ' Habitat Species in the genus Thcrcva seem re- stricted to mountainous areas and to the northern boreal and coniferous zones in North America. Ii-win reared larvae from mixed montane leaf litter from the San Bernardino Mountains in southern Cali- fornia. Distribution The genus Thcrcva ranges widely over the Holarctic Region and parts of the Afrotropical Region (Lyneborg 1976; Lyneborg & Spitzer 1974) , but within the Western Hemisphere it is generally con- fined to the boreal and mountainous areas of western, northern, and eastern Nortli America. Included Species albopilosa Krober 1912:256 $ . Distri- bution. — Colorado. I Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 219 aurofasciata Krober 1912:263 $ . Dis- tribution. — Southern Colorado. bakeri Cole \923a -.124: $, $. Distri- bution. — Southern CaHfomia. brunnea Cole 1923a: 108 5,9. Dis- tribution. — British Columbia, Can- ada, and Washington. cingulata Krober 1912:267 ? . Distri- bution. — Colorado. comata Loew 1869(z : 7 3 . Distribution. — California. concavifrons Krober 1914:70 9. Dis- tribution. — New Mexico. diversa Coquillett 1894:100 S . Distri- bution. — Colorado. rfMp/zm Coquillett 1893a: 198 3, 9. Distribution. — South Dakota and Montana. egressa Coquillett 1894:99 $. Distri- bution. — Colorado. flavicauda Coquillett in Baker 1904: 23 9 . Distribution. — Nevada. flavicincta Loew 1869^:168 S- Dis- tribution. — Northeastern United States. gilvipes Loew 1869&:168 9. flavipilosa Cole 1923a: 125 S. Distri- bution.— Fresno County, California. flavohirta Krober 1914:70 9. Distri- bution.— Colorado. foxi Cole 1923fl:112 S. Distribution. — Washington. frontalis Say 1824:370 5, 9. Dis- tribution. — Northwestern United States and southwestern Canada. fucata Loew 1872:74 S, 9. Distri- bution. — California. fucatoides Bromley 1937:99 $, 9. Distribution. — Utah. hirticeps Loew 1874:382 9. Distribu- tion. — San Francisco Bay area, Cal- ifornia. johnsoni Coquillett 1893a: 200 9 . Dis- tribution. — Washington. macdunnoughi Cole 1925:87 5, 9. Distribution. — Alberta, Canada. nebulosa Krober 1912:264 $. Distri- bution. — California. neomexicana Cole 1923a: 117 9. Dis- tribution. — Southern Nevada. nigripilosa Cole 1923a: 110 $. Distri- bution. — British Columbia, Can- ada. niveipennis Krober 1914:66 $. Dis- tribution. — Central coastal Cali- fornia. pseudoculata Cole 1923a: 121 $, 9. Distribution. — Utah. strigipes Loew 1869fo:169 9. Distri- bution. — Winnipeg, Canada. ustulata Krober 1912:265 $. Distri- bution. — Winnipeg, Canada. utahensis Hardy 1938:145 9. Distri- bution. — Utah. Genus Tabudamima Irwin & Lyneborg, new genus (Fig. 88-93) Feminine Derivation of name: Tahuda ^= genus name in the Therevidae; mimos (Greek) or mimus (Latin) = imitator. Type-species: Thereva melanophleba Loew 1876: 112 by present designation. Type-locality: San Francisco, Cali- fornia. Diagnosis Small, moderately broad species. Head. — Frons of male at its narrow- est narrower than width of anterior ocellus; frons of female 1.8-2.0X as wide as ocellar tubercle; male frons entirely tomentose, with long, black pile; tomen- tum on frons gray; female frons entirely tomentose, often with dark transverse band and shorter pile than that of male; frons impressed; head noticeably pro- trudes anteriorly; facial and genal calli absent; lateral portion of face and gena has long pile, black on face, white on gena; head depth 1.0-1.1 X antennal length; scape thickened, 1.3—1.5 X length of flagellum ; flagellar style apical, ob- viously one segmented, with a minute terminal spine; palps one segmented. Thorax. — np 3, sa 1, pa 1, dc 0, sc 2 ; mesonotal pile in male very long, uni- form, composed of white and black hairs; mesonotal pile in female of two types: the first is moderately long, scalelike, semi-appressed, white, and the other is long, erect, black; prosternum without pile in and around central depression (this may be difficult to discern because of long, dense pile on fore coxa). Wing. — Cell ma closed or narrowly open ; vein 220 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 Fig. 88—93. — Tabudamima mehnopbteba (Lw.) male terminalia. 88.— Genitalia in lateral view. 89.— Right gonocoxite with appendages and aedeagus in dorsal view. 90.— Epandrium with ap- pendages in dorsal view. 91. — Aedeagus in lateral view. 92. — Sternite 8. 93. — Tergite 8. Scale: 0.5 mm. R4 longer than vein R5; cell r4 2. 1-2.2 X as long as wide at apex; color grayish hy- aline in male, but has more brownish tinge in female; veins very strong and dark; vein R4 often has recurrent vein near base; stigma blackish brown. Legs. — Fore coxa has at most a single, apical seta on anterior surface ; middle coxa has whitish pile on posterior surface; hind femur has 4-5 anteroventral setae. Abdomen.— Slender, gradually taper- ing from segment 2 to apex; abdomen not telescoped; dorsum somewhat flat- tened in both sexes; dorsum of male en- tirely tomentose and pilose; tomentum silveiy white; dorsum of female has broad, blackish anterior bands on first tergites, otherwise tomentose; tomentum gray on female dorsum. Male Terminalia (Fig. 88-93). — Tergite 8 (Fig. 93) comparatively large and greatly constricted medially; sternite 8 (Fig. 92) large, broad oval, with semi- circular incision in posterior margin ; epandrium (Fig. 90) shorter in midline than wide, its posterolateral corners prominently extended, but simply rounded; cerci free, strongly sclerotized, elongate, but not extending beyond ven- tral epandrial sclerite; ventral epandrial sclerite only sclerotized beyond cerci, con- tinuing anteriorly into a weak membrane reaching to about middle of epandrium, with no attachment to aedeagus; para- meral apodeme without attachment to aedeagus; distiphallus (Fig. 89) gradu- ally tapers, in lateral view (Fig. 91) short and only moderately curving; dorsal apodeme oval; ventral apwdeme short and broad; ejaculaton' apwdeme shaped like a rod; ventral lobes of gonocoxites large, rather complex and have a mem- branous attachment to ventral surface of aedeagus; parameral process moderately long and slender (Fig. 89) ; gonocoxites not united ventrally, not even attached by a membrane: in lateral view (Fig. 88") gonocoxites nearly circular in shape; hy- pandrium (Fig. 89) free, forming a long, very narrow strip. Habitat Little is known of tlie habitat of diese species except that several specimens were collected in coastal sand dune habi- tats in California. Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 221 Distribution Species in the genus Tabudamima seem confined to the northwestern United States, with specimens collected from Washington, Oregon, California, and Nevada. Those from California are con- centrated in the San Francisco Bay area southward along the coast to San Diego County and inland in the Sierra Nevada Mountains and in the San Bernardino and Santa Rosa mountains of southern California. Included Species mclanophlcba (Loew) 1876:317 $, 9 (Thcrcva), new combination. Distribution. — San Francisco Bay area, California. There are several closely related unde- scribed species in this genus. Genus Tabuda Walker (Fig. 6, 7, and 94-100) Tabuda Walker 1852:197. Type-species: Thereva julvipes Walker 1852:197 by original monotypy ( = T. varia Walker 1848:221). Type-locality: Florida. Metaphragma Coquillett 1894:97. New synonym. Type-species : Xestomyza planiceps Loew 1872:75 by original designation. Type-locality: California. Diagnosis Medium- to large-sized, robust flies. Head (Fig. 6 and 7) . — Frons of male at its narrowest from as wide as anterior ocellus to as wide as ocellar tubercle: frons of female at level of anterior ocellus about 2.5 X as wide as ocellar tubercle; frons without distinct tomentum pattern, or at most with a pair of small, dark patches laterally: pile on lower frons moderately thick, composed of long, black hairs; upper frons bare or has thin jjile laterally; head moderately to promi- nently protruding anteriorly, antennae thus set on a distinct protuberance; facial and genal calli absent; lateral portion of tace and gena has long pile; head depth 1.0-1.3X antenna! length; scape thick- ened, 1.7-2.OX as long as flagellum; flagellar style apical, stout, obviously one segmented, with a minute terminal spine; palps one segmented. Thorax. — np 3-5, sa 2, pa 1, dc 1, so 2; mesonotal pile of two types: one is moderately long, scalelike, rather dense, semi-appressed, and the other is long, erect, sparse; prostcrnum without pile in and around central depression. Wing. — Cell nis open; vein R4 longer than vein R5; cell r4 2.3-2.6X as long as wide at apex; color grayish brown to brown, with darker stigma or anterior margin inten- sively darkened, and with darker patches, especially around crossveins. Legs. — Fore coxa with 1 or 2 apical setae on anterior surface; middle coxa with whitish pile on posterior surface; hind femur with 5-8 anteroventral setae. Abdomen.— Rather broad, with sides nearly parallel from segments 1 through 3; thereafter, abdomen tapers slightly and gradually; male abdomen distinctly telescoped; abdominal tergites 6 and 7 visible only as narrow bands; dorsum of abdomen somewhat flattened; male dor- sum has silver gray tomentum; female dorsum mostly subshiny to dull brown. Male Terminalia (Fig. 94-100). — Tergite 8 (Fig. 100) small and greatly constricted medially; stemite 8 (Fig. 99) small, oval, has a semicircular incision into posterior margin; epandrium (Fig. 97) shorter in midline than wide, its posterolateral comers rounded ; cerci free (Fig. 97), strongly sclerotized, elongate, extending distinctly beyond ventral epan- drial sclerite ; ventral epandrial sclerite reaches or nearly reaches anterior mar- gin of epandrium, but has at most a loose and weak attachment to anterior margin of aedeagus; ventral epandrial sclerite has three strongly sclerotized areas: a small semicircular area below cerci and a larger pair below epandrium; para- meial apodeme and ventral lobes of gonocoxite not attached to aedeagus; disti|)hallus (Fig. 98) rather long, S curved ; a semicircular, narrow, sclero- tized ring in dorsal membrane surrounds 222 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 Fig. 94—100.— Tabuda varia Wlk. mole terminalla. 94. — Genitalia in lateral view. 95. — Gono- coxites and hypandrium in ventral view. 96. — Gonocoxites with appendages and aedeagus in dorsol view. 97. — Epandrium with appendages in dorsal view. 98. — Aedeagus in laterol view. 99. — Sternite 8. 100. — Tergite 8. Scale; 0.5 mm. proximal portion of ejaculatoiy apodeme ; ventral apodeme large, narrowly spoon shaped distally; ejaculatory apodeme has enlarged proximal and distal sections; ventral lobes of gonocoxite (Fig. 96) small, narrow, directed upward, but not visible in ventral view; parameral pro- cess strongly united with dorsal surface of gonocoxite, at most a wartlike process present; parameral apodeme distinct but small; gonocoxites (Fig. 95) not united ventrally, short and high in lateral view (Fig. 94), project dorsally; h^-pandrium (Fig. 95) free, foiTning a long, narrow band adjoining anterior margin of gono- coxites for a long distance. Habitat Little is known as to the habitat that these interesting looking flies occupy. One specimen of planiceps was collected in sand dunes near San Francisco. Two specimens of borcalis were collected on sand near coyote holes (Cole 1923a: 83). Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 223 Distribution Species of Tabuda appear to be con- fined to the western coast of North America {T. planiceps) , eastern North America [T. varia) , and north-central North America {T. horealis). Included Species borealis Cole 1923a: 82 5, ?. Distri- bution. — Saskatchewan, Canada. planiceps (Loew) 1872:75 2 [Xesto- myza) , new combination. Distribu- tion.— Western coast of North America from British Columbia, Canada, southward to southern California, United States. varia (Walker) 1848:221 ? [The- reva) , new combination. Distribu- tion.— Eastern North America from Florida northward to Massachusetts and westward to Pennsylvania. julvipes Walker 1852: 197 $ , new u name for Thereva nervosa Walker. nervosa Walker 1848:223 $ {Thereva), not Loew 1845:28. No undescribed species of Tahuda are known to us. Note The genus Metaphragma was created by Coquillett (1894:97) for Xestomyza planiceps Loew 1872:75. T. planiceps is unique in having an additional crossvein between R5 and vein Mi that forms a 1 closed cell anterior to the discal cell. This additional cell is similar in shape and size to the discal cell; however, in characters such as those of the male terminalia, planiceps falls within the strict definition of Tabuda. For that rea- son we have synonymized Metaphragma Coq. with Tabuda Walker. Genus Acrosathe Irwin & Lyneborg, new genus (Fig. 101-106) Feminine Derivation of name: akra (Greek) = projection; sathe (Greek) = phallus. Type-species: Bibio annulata Fabricius 1805:68 by present designation. Type- locality: Denmark. Diagnosis Medium-sized, moderately thick-bodied species. Head. — Frons of male at its narrow- est narrower than width of anterior ocellus (in bimaculata (Cole) about 3X as wide as anterior ocellus) ; frons of female at level of anterior ocellus 1.3— 2.4X as wide as ocellar tubercle; male frons tomentose; tomentum silvery white to gray, upper comer more or less dull black or brown (with two dull darkened areas in bimaculata) ; male frons has long, usually pale, pile; lower part of female frons tomentose and pilose, as in male, tomentum silvery gray, pile pale straw; upper part of female frons to- mentose, often with dull black areas, tomentum brownish to brownish gray, pile brown or black; head distinctly pro- trudes anteriorly at antennal level ; lateral portion of face and gena has long, pale pile; head depth 1.2-1.5X antennal length; scape slender, 0.8-1 .OX as long as flagellum; flagellar style apical, two segmented, with a small terminal spine; palps one segmented. Thorax. — np 3-4 (usually 3), sa 1- 2 (usually 2), pa 1, dc 1-2, sc 2; meso- notal pile of male of some species long, erect, uniform ; mesonotal pile of male of other species and of all females of two kinds: one is long to moderately long, erect, normal, and tlae other is shorter, semi-appressed, scalelike; prosternum has long pile in and around central de- pression. Wing. — Cell m^ in most spe- cies closed and has short common vein to wing margin; cell ma occasionally open; vein R4 distinctly longer than vein R5; cell Ti 2.0-2.2 X as long as wide at apex; color grayish hyaline, but a couple of species show brownish infuscations around crossveins; stigma pale brown. Legs. — Fore coxa with 2 or 3 apical setae on anterior surface; middle coxa has whitish pile on posterior surface ; 6-8 rather stout anteroventral setae over en- tire length of hind femur. Abdomen. — Moderately broadly built, gradually tapering from segment 2 to apex, not telescoped; dorsum somewhat 224 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 flattened in both sexes; dorsum of male entirely tomentose and pilose, these being silvery white to gray; dorsum of female in most species has dark anterior bands on at least tergites 2-4, but a couple of species have tergites entirely tomentose, tomentum gray. Male Terminalia (Fig. 101-106). — Tergite 8 (Fig. 105) large, wider than epandrium, and medially constricted for a long distance; sternite 8 (Fig. 106) trapezoidal, its lateral margins straight or concave; posterior margin of sternite 8 has semicircular incision; epandrium (Fig. 103) large, markedly convex, as long medially as, or longer than, wide; posterolateral comers of epandrium trun- cate in type-species (Fig. 103), more sharply pointed in North American spe- cies; cerci free, ventral epandrial sclerite well sclerotized below cerci, continuing anteriorly into a weak, narrow mem- brane, often loosely attached to anterior margin of aedeagus; some species ha\e a strong, narrow attachment bet%veen lateral edge of epandrium/ventral epan- drial sclerite and midsection of paramere : parameral apodeme without attachment to aedeagus; distiphallus (Fig. 102) slen- der, in lateral view (Fig. 104) more or Fig. 101-106. — Acrosafhe annulalo (F.) male terminalio, 101. — Genitalia in ioleral view. 102. — left gonocoxite with appendages and aedeagus in dorsal view. 103. — Epandrium with appendages in dorsal view. 104. — Aedeagus in lateral view. 105. — Tergite 8. 106. — Sternite 8. Scole; 0.5 mm. Nov., 1980 Irwin & Lyneborg : The Genera of Nearctic Therevidae 225 less downcurved; dorsal apodeme short; ventral apodeme large, forming a narrow, deep trough; 2 anterior processes arise from base of distiphallus; these processes either shorter than or as long as disti- phallus ; they are distinct at species level ; ejaculatory apodeme simple, stick shaped; ventral lobes of gonocoxites, as in Psilo- ct'phala (Fig. 110), large, heavily sclero- tized, and suddenly curved, forming a dorsal, anteriorly directed, distal portion strongly attached to midlateral section of aedeagus; parameral process large, free; gonocoxites free ventrally, but at- tached by a membrane; hypandrium (Fig. 102) narrow, comparatively large. Habitat The type-species is widespread in Europe, occurring mainly on coastal dunes. Most of the North American spe- cies are found in coastal dunes, but A. vialis inhabits mountainous areas and is often found on lake beaches. Distribution The genus Acrosathe is Holarctic, with about 10 species occurring in the Pale- arctic Region. Within the Nearctic Re- gion, one species, A. bimaculata, is found in North Carolina; the other species are confined to western North America (British Columbia, Washington, Oregon, Idaho, California, Baja California) . Included Species bimaculata (Cole) 1923a:98 § [The- reva) , new combination. Distribu- tion. — North Carolina. novella (Coquillett) 1893a:200 3, 9 [Thereva] , new combination. Dis- tribution. — .Southern California. o/wi-a (Coquillett) 1893a: 199 ,5 [The- reva) , new combination. Distribu- tion. — Coastal area of California. pacifica (Cole) 1923a: 103 S, 9 [Thereva], new combination. Dis- tribution.— Coastal area of central California. vanduzeei (Cole) 1923a: 105 3, ? [Thereva) , new combination. Dis- tribution. — Coastal area of north- central and northern California. vialis (Osten Sacken) 1877:274 $ [Thereva) , new combination. Dis- tribution. — Sierra Nevada Moun- tains, California. There are a number of undescribed species from the inland parts of western North America. Genus Psilocephala Zetterstedt (Fig. 10, 11, and 107-114) Feminine Psilocephala Zetterstedt 1838:525. Type- species: Bibio imberbis Fallen 1814:5; subsequent designation (Coquillett 1910:597). Type-locality: Sweden. Diagnosis Medium- to large-sized, thin to mod- erately broad species. Head. — Frons of male at its narrow- est distinctly narrower than half width of anterior ocellus; frons of female at level of anterior ocellus 1.8-1.9 X as wide as ocellar tubercle; male frons to- mentose and without pile, tomentum sil- very gray; female frons tomentose an- teriorly, upper three-quarters shiny blackish with a circular, depressed, wrinkled area medially, tomentum sil- very gray; blackish part of frons has short, black pile; head only very slightly protrudes at antennal level; lateral por- tion of face without pile; gena has whit- ish pile similar to, but shorter than, lower occipital pile; head depth 1.3-1.6 X an- tennal length; scape slender, 0.4-0.5 X as long as flagellum ; flagellar style apical, two segmented, with a small terminal spine; palps one segmented. Thorax. — np 3, sa 2, pa 1, do 2, sc 2 ; mesonotal pile of male long, erect and uniform, composed of pale and darker hairs, which are distinctly longer than width of scape; mesonotal pile of female much shorter, entirely dark, partly erect, partly semi-appressed ; presternum bare in and around central depression. Wing. — Cell m.-i usually closed, rarely open, and common vein usually short; veins R4 and Rr, about equal in length; cell r4 about 2.5 X as long as wide at apex; color hyaline with faint brownish tinge; i 226 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 stigma pale brown ; no other markings on Abdomen. — Rather broadly built, in wing. Legs.— Fore coxa has 2 or 3 apical setae on anterior surface; middle coxa without pile on posterior surface; hind femur has 3-4, rather slender, an- teroventral setae. male gradually tapering from segment 3 to apex; in female tapering from seg- ment 5 to apex ; abdomen not telescoped ; dorsum convex in male, more flattened in female; male dorsum entirely tomen- Fig. 107—114. — Psilocephala imberbis Fall, male terminolia. 107. — Genitalia in lateral view. 108. — Gonacoxites with appendages and hypandrium in ventral view, 109. — Left gonocoxite with appendages and aedeagus in dorsal view. 110. — Right gonocoxite with appendages in ventral view. HI.— Epondrium with appendages in dorsal view. 112. — Aedeagus in lateral view. 113. — Sternite 8. 114. — Tergite 8. Scale: 0.5 mm. List of abbreviations appears on pages 194 and 195. Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 227 tose except for polished black terminalia, tomentum silvery gray; female dorsum mostly shining black, but with marked pattern of silvery gray tomentum on seg- ments 1-3 and 5-6. Male Terminalia (Fig. 107-114). — Tergite 8 (Fig. 114) wide, greatly con- stricted for a short distance medially; stemite 8 (Fig. 113) nearly semicircular, only slightly incised along posterior mar- gin; epandrium (Fig. 107 and 111) no- ticeably convex, shorter in midline than wide, but has prominently projecting posterolateral comers, which are broadly lamellate; cerci free, well sclerotized, not projecting beyond ventral epandrial sclerite; ventral epandrial sclerite strongly reduced, restricted to a distinctly bilobed sclerite lying below and similar in size to cerci; apparently membrane lacking beneath epandrium; parameral apodeme without attachment to aedeagus; disti- phallus (Fig. 109) in dorsal view nearly circular, in lateral view (Fig. 112) quite flat and straight; dorsal apodeme nar- row proximally, but gradually wider to- ward apex; ejaculatory apodeme very slender; ventral lobes of gonocoxites (Fig. 110) large and strongly sclerotized, rising first in a vertical position, then suddenly curving anteriorly and termi- nating distally in a section firmly at- tached to midlateral part of aedeagus; ventral lobes not, or at most very weakly, attached along midline (Fig. 108) ; para- meral process strongly sclerotized and lather broad; parameral apodeme long, narrow; gonocoxites not united ventrally, not even by a distinct membrane; gono- coxites truncate in lateral view (Fig. 107) ; hypandrium present as a small, triangular sclerite (Fig. 108). Habitat Specimens in this genus occupy for- ested zones. Very little is known of spe- cific habitats. Distribution The genus Psilocephala is Holarctic. Within the Nearctic Region, specimens at hand are from these areas: Canada (Nova Scotia, Quebec, Ontario, Mani- toba, Saskatchewan, Alberta, Yukon Ter- ritory, District of Mackenzie, and British Columbia) ; United States of America (Alaska, Washington, Oregon, northern California, Utah, Wyoming, Colorado, Montana, Wisconsin, Minnesota, Michi- gan, Pennsylvania). One male specimen is labeled from Douglas, Arizona. This specimen appears to be from outside the normal range of the genus, or it might be mislabeled. Included Species conspicua (Walker) 1848:223 9 (Thereva) . Distribution. — Nova Scotia. munda Loew 1869a: 9 $ . Distribution. — Great Lakes Region of North America. melanoprocta Loew 1869a: 11 $, subsequent synonymy (Krober 1912:239). vicina (Walker) 1848:222 3 [The- reva) . Distribution. — Nova Scotia. P. conspicua (Walker) and munda (Loew) may well prove to be synony- mous with vicina (Walker). The western specimens have not been studied closely; they could represent one or more distinct, undescribed species, or they could prove to be western popula- tions of vicina (Walker) or munda (Loew) . Genus Penniverpa Irwin & Lyneborg, new genus (Fig. 25 and 115-121) Feminine Derivation of name: penna (Latin) = feather; verpa (Latin) = penis. Type-species: Psilocephala festina Co- quillett 1893fc:225 by present designa- tion. Type-locality : Florida. Diagnosis Small- to medium-sized flies of very slender build. Head. — Frons of male at its narrow- est narrower than half width of anterior ocellus; frons of female narrow, at level of anterior ocellus 1.0-1.3 X as wide as ocellar tubercle; male frons high, nar- row, entirely tomentose and without pile, tomentum .silvery (one species from Peru has a silvei7 golden tomentose frons 228 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 Fig. 115—121. — Penniverpa festina (Coq.) male terminolia, 115. — Gonocoxites with oppendoges and hypandrium in dorsal view; the natural positions of the anterior and posterior ends of aedeagus ore shown. 116. — Epandrium with appendages in dorsal view. 117. — Left gonocoxite with ventrol lobe and gonostylus in caudal view. 118. — Aedeagus in lateral view. 119. — Aedeagus in dorsal view. 120. — Ter- gile 8. 121. — Sternile 8. Scale: 0.5 mm. with a few stout hairs on its lower half) ; female frons entirely tomentose, either uniformly silveiy or upper part darker than lower part; female frons has short, sparse black pile on upper half; head moderately protrudes anteriorly; lateral portion of face without pile; gcna bare or with sparse white pile; head depth 1.5-1.8X antennal length: scape slender, 0.3-0.5 X as long as flagellum; flagellar style apical, two segmented, with a small terminal spine; palps one segmented. Thorax. — np 3-4, sa 2, pa 1, dc 0, so 1-2 (usually 1 ) ; mesonotal pile of two kinds: the first scmi-appressed, pale, and the other erect, black, usually shorter than scape; mesonotal pile of male gen- erally longer and denser dian that of fe- male; presternum has pile in and around central depression. Wing. — Cell nia broadly open; \ein K^ slightly longer than Rs; cell r4 about 2.6-2.8 X as long as wide at apex; color hyaline with pale brownish stigma. Legs. — Fore coxa has 2 strong apical setae on anterior surface; middle co.xa without pile on posterior surface or with a little pile in that jxisi- tion in one South American species; hind femur has at most 3-4 short, slender anteroventral setae. Foreleg (Fig. 25) exceptionally long. Abdomen.— Slender in both sexes, en- tirely cylindrical in male, doi'sum more flattened in female, tapering from seg- Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 229 ment 2 to apex; male dorsum entirely covered by silver tonientum and whitish pile; female dorsum has pattern of black- ish bands and whitish tomentose areas. Male Terminalia (Fig. 115-121). — Tergite 8 (Fig. 120) about as wide as epandrium and greatly constricted me- dially; sternite 8 (Fig. 121) rectangular, with incisions in both anterior and pos- terior margins; epandrium (Fig. 116) shorter in midline than wide, its postero- lateral comers broadly rounded; cerci (Fig. 116) rather weakly sclerotized and finely haired, fused along basal part; ventral epandrial sclerite projects slightly more than cerci ; posterior section of ven- tral epandrial sclerite rounded; a setose pair of S-cuived sclerites attached by membranes to posterior edge of epan- drium; these sclerites not attached over midline by a distinct membrane, but their anterioiTnost corners are loosely attached by weak membranes to anterior margin of aedeagus; parameral apodeme without attachment to aedeagus; aedeagus (Fig. I 118 and 119) long and slender; disti- phallus in lateral view (Fig. 118) very flat and gently downcurved, a double row of long setae on proximal part; dorsal apodeme (Fig. 119) long and slender; ventral apodeme (Fig. 119) as long as or longer than dorsal apodeme, in dorsal view gradually tapering ; 2 processes arise from midsection of aedeagus, nearly par- allel to distiphallus and pointed apically; these processes converge, and the usually setose apices meet either above or below the distiphallus in lateral view; ejacula- toiy apodeme veiy slender and short, completely contained between dorsal and ventral apodemes in dorsal view; ae- deagus loosely attached to ventral lobes of gonocoxites; ventral lobes (Fig. 115 and 117) complicated, rising dorsally, fonning a lamellate structure, and often having a spine on exterior surface not lar from the distal, dorsal edge; the gonostylus (Fig. 115 and 117) remark- ' ably complicated, showing many modifi- < ations in several undescribed species; 'gonostylus more or less U shaped, com- posed of exterior and interior ventrally .united sections; interior section relatively consistent in shape; exterior section with strong modifications, from a simple tooth, or a long process with a group of distal spines and a narrow projection stretching toward the ventral lobe (as in the type- species), to the distal spines being absent and the narrow projection being replaced by strong setae ; many more modifications will certainly emerge when the numerous species are described; parameral process long, free; gonocoxites free ventrally, at- tached by a weak membrane; a distinct, free hypandrium present, but not always as large as illustrated (Fig. 115). Habitat We have only encountered a few spe- cies in nature. All have been found in veiy sandy areas or in dry sandy washes. A species from Lima, Peru (probably gracilis Krober 1911:507) was captured abundantly in a sandy cornfield. Distribution Judging from the material at hand, we conclude that this genus occurs in the southern United States (Arizona, Texas, Florida, and Georgia) and south- ward through Mexico, the West Indies (Cuba, Jamaica, and Trinidad), Central America (Panama, Honduras, and Gua- temala) , and portions of South America (British Guiana, \'enezuela, Brazil, Ecua- dor, Peru, and Bolivia) . Included Species festina (Coquillett) 1893&;225 $, ? {Psilocephala) , new combination. Distribution. — Georgia, Florida. (Other literature records probably refer to other, closely related, mostly undescribed species. ) At least four additional species, all from South America, can be placed in the genus Pennivcrpa, including senilis (Fabricius) ( 1805 :68) , new combination, which was reported by Lyneborg (1969: 390) probably to be from northeastern South America. Several undescribed spe- cies are mainly from the West Indies and Central and South America, but at least one undescribed species occurs in Texas, Arizona, and northeastern Mexico. 230 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 Genus Lysilinga Irwin & Lyneborg, new genus (Fig. 122-127) Feminine Derivation of name: lysis (Greek) ~ free, loose; linga (Sanskrit) = penis. Type-species: Psilocephala aurantiaca Coquillett 1904fe: 177 by present desig- nation. Type-locality: Claremont, Cal- ifoiTiia. Diagnosis Medium-sized, slender-bodied species with little pile on body. Head. — Compound eyes of male nearly touch for a considerable distance; eyes of male not divided into two distinct facet sizes. Frons of female narrow, upper half only slightly wider than ocellar tubercle, with lower half expanded to slightly more than twice width of upper half. Head about 1.2-1.4X wider than high; ratio of the distance between the lower, inner corners of compound eyes and head height 0.5-0.6; antennae rather low on head, inserted at three-fifths of head height; width of head 2.6-3.0 X that of frons at antennal insertion ; genae small, rounded, tomentum undifferenti- ated from that of face. Head hypogna- thous; proboscis small, fitting into sub- cranial cavity and not reacliing antennal base; palps one segmented, slender, rod- like, usually pale colored, thinly pilose, shorter than proboscis. Head depth 1.2- 1.4X antennal length; scape 0.4-0.6X as long as flagellum; fiagellum laterally com- pressed, pear shaped, wider (dorsoven- trally) than scape; flagellar style short, of apparently two segments plus terminal spine. Short, sparse, appressed pile on upper frons of female. Frons and face of male usually without pile or setae (in L. occipitalis occasional specimens have a few setae on lower central frons) , cov- ered with dense, silvery tomentum. Lower frons and face of female and genae and occiput of both sexes also densely to- mentose, tomentum silvery. Upper frons of female usually has siKeiy to brown tomentum and a pair of usually large, brown velvety spots tangential to each compound eye at division of browTi and silvery tomentum. (In an undescribed Fig. 122—127.— Lysitinga aurantiaca (Coq.) male terminalia. 122. — Right gonocoxite with append- ages and aedeagus in dorsal view, 123. — Gonocoxites, hypandrium, and aedeagus in ventral view. 124. — Epandrium with appendages in dorsal view. 125. — Aedeagus in lateral view. 126.— Sternite 8. 127. — Tergite 8. Stole: 0.5 mm. I Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 231 species from Mexico, the velvet spots are very small.) Head deeper ventrally than dorsally, giving the appearance, when viewed laterally, of a rounded isosceles triangle, the ocelli foraiing a point and the lengths of occiput and frons forming I the long sides. The side from the anten- , nae to the lower genae appears rounded. Ocellar tubercle has sparse, short setae in some species, lacks setae in otliers. Thorax. — np 3, sa 2, pa 1, dc 0, sc 1-2; thoracic setae from dark brown to black (L. aurantiaca, undescribed spe- cies from Mexico) to yellowish white (L. occipitalis, L. subrufa) . Mesonotal pile short, sparse, appressed, yellow-metal- , lie scalelike, more abundant on males. Mesonotal tomentum grayish to brown i with no discemable pattern of vittae. 1 Prostemum has elongate white pile in and around central depression. Wing. — Cell ms widely to narrowly open; ratio of lengths R4/R=, 1.0-1.1; cell r^ 2.2- 2.6X longer than wide at apex; wings I hyaline with a darkened area around I. stigma (and cell ri darkened in males of an undescribed species from Mexico) . Legs. — Fore coxa has 2 large setae on apical half of anterior surface; middle coxa has pale, sparse, scalelike pile on posterior surface; fore femur has a single seta in the av position; middle femur without setae; hind femur has a row of av and pv setae, av setae fewer but stouter than pv setae. All femora have scalelike pile, especially along dorsal margin. Abdomen. — Slender, tapering toward apex, cylindrical in cross section; ab- dominal segments not telescoped; pile sparse, appressed, usually short. Tomen- tum of both sexes silvery, generally re- stricted to posterior margins of tergites 1, 2, 3 and often 5 and 6 (except in male of undescribed species from Mexico that has silvery tomentum covering abdo- men). Ground color often red, orange, yellow, or light brown. Male Terminalia (Fig. 122-127). — Tergite 8 elongate, bilobate at lateral margins, very thin medially (Fig. 127) ; sternite 8 a small bilobate sclerite (Fig. i26). Epandrium large (Fig. 124), slightly wider than long measured along midline; posterolateral margins not mod- ified. Cerci elongate, shorter than ven- tral epandrial sclerite, separate from one another; ventral epandrial sclerite simple elongate, not keeled, not deeply cleft; intersegmental membrane basad of ventral epandrial sclerite weakly sclerotized laterally, connecting to sclerite and anterior margin of aedeagus (this connection not obvious because of trans- parent membrane) ; this membrane also attached to posterolateral portion of epandrium. Gonocoxites (Fig. 122 and 123) free for their entire length; hypan- drium narrow, bridgelike, connecting gonocoxites; parameral process absent although gonocoxites project posteriorly and greatly enlarged; parameral apodeme attached to lateral margin of dorsal apodeme by thin, transparent membrane. Ventral lobes of moderate size, dentate, not upright, weakly attached to center of aedeagus, free from one another (Fig. 123) ; gonostylus elongate, reaching apex of expanded gonocoxite, twisted dorsally like a large hook ; ratio of aedeagus basad of center/distad of center about 1/1; ratio of width of phallus base/width of dorsal apodeme, 4/1. Aedeagus (Fig. 122 and 125) of moderate size; distiphal- lus short, strongly curved, with a peculiar hoodlike appendage above and projecting posteriorly; ventral apodeme short, nar- row, about as long as ejaculatory apo^ deme; dorsal apodeme heavily sclero- tized laterally into two parallel bars; distal end of ejaculatory apodeme slightly enlarged laterally, dorsoventrally flat- tened. Habitat Little is known about the habitat of various species of Lysilinga. In Riverside, southern California, a malaise trap set in a small wash on a sparsely vegetated hillside yielded several specimens of L. aurantiaca over a period of several months. Distribution Lysilinga is, judging from sjiecimens examined, confined to western North 232 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 America: southern California, Arizona, and New Mexico in the United States; Sonora, Chihuahua, Oaxaca, and Guer- rero in Mexico. Included Species aurantiaca (Coquillett) 1904i>:177 3 (Psilocephala) , new combination. Distribution. — Southern California, Arizona, and New Me.xico; Sonora, Mexico. occipitalis (Adams) 1904:443 S {Psi- locephala), new combination. Dis- tribution. — Southern California, Arizona, and New Mexico; Sonora and Chihuahua, Mexico. subrufa (Cole) 1923a: 68 ? {Psilo- cephala), new combination. Dis- tribution. — Arizona and southern California. (This species maybe con- specific with L. occipitalis.) There is one undescribed species from Guerrero and Oaxaca in southwestern Mexico. Genus Brachylinga Irwin & Lyneborg, new genus (Fig. 18 and 128-135) Feminine Derivation of name: brachys (Greek) = short; linga (Sanskrit) = penis. Type-species: Psilocephala baccata Co- quillett 1893t>:226 by present designa- tion. Type-locality: Los Angeles and San Bernardino counties, California. Diagnosis Small- to medium-sized, often slender species. Head. — Compound eyes of male touch to nearly touch for a short dis- tance; eyes of male not divided into two distinct facet sizes. Frons of female (Fig. 18) rather narrow in most species, upper half only slightly wider than ocellar tubercle, lower half expanded to 2-3 X width of ocellar tubercle. In an unde- scribed species from San Bias, Nayarit, Mexico, female frons very wide, 2.3 X width of ocellar tubercle at level of an- terior ocellus, 4X width at antennal in- sertion. Head squat, 1.2-1.6X wider than high; distance between lower, inner cor- ners of compound eyes 0.6-0.8X head height; antennae about midway or slightly lower on head, between 40 and 70 percent of head height above antennal insertion; genae small, rounded, tomen- tum usually undifferentiated from that of face (small group of species along Pacific Coast from Sonora, Mexico, to Panama has differentiated tomentum on genae). Head slightly prognathous in most species, hypognathous in others; proboscis relatively large, reaching to or slightly beyond base of antennae in most species: palps Vi-Vi length of proboscis, often yellowish to yellowish-brown. Head depth 1.2-1.4X antennal length; scape 0.5-0.8 X as long as flagellum; first flagel- lomere pear shaped to elongate; dorsal portion of scape sparsely to densely cov- ered with thickened, dark setae ; antennae covered with a fine tomentum; flagel- lar style short, of apparently two seg- ments plus terminal spine. Pile on fixins of male variable, from absent to abun- dant, from erect to appressed, from short to long: pile on female also variable al- though never entirely absent. Frons, face, genae, and occiput clotlied in coarse to fine pi-uinose tomentum, often brown. gray, or silveiy; upper and lower frons not differentiated by pattern or color of tomentum; frons of female (Fig. 18) often has a velvety brown spot tangential to each compound eye ; this spot large and round or small and flattened against eye margin; in some species no spot is evident. Frons of male either with or without small spot; if spots exist, they are flattened against each compound eye. Ocellar tubercle has few to several setae. Thorax. — np 3, sa 1-2 (usually 2), pa 1, dc 0-2 (usually 2), sc 2; thoracic setae dark brown to black. Mesonotal pile generally spai-se, thin, erect, with scalelike, bronze-colored appressed pile; pile generally denser on males than on females. Mesonotal tomentum usually grayish to brown without discernible pat- tern of \ittae. Wing. — Cell m,, fmm widely open to closed : ratio of lengths R4/R5 about 1.0-1.1; cell r^ 2.0-3.2\ longer than wide at apex: \vings hyaline Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 233 Fig. 128—135.— Rrachylinga baccata (Coq.) male terminalia, 128. — Gonocoxites and hypandrium in ventral view. 129. — Left gonoccxite with appendages and aedeagus in dorsal view. 130. — Left gonoccxite and gonostylus in lateral view. 131. — Epandrium with appendages in dorsal view. 132. — Ventral epandrial sclerite. 133.— Aedeagus in lateral view. 134. — Sternite 8. 135. — Tergite 8. Scale; 0.5 mm. with a darkened area around stigma in some species and darkened areas sur- rounding the veins in a few species. Legs. — Fore femur has 0-1 av setae (usually 1 ) ; middle femur has no setae ; hind fe- mur has a sparse row of av and pv setae ; scalelike, appressed as well as thin, erect pile on all femora. Abdomen.— Slender (especially in male), tapering toward apex, cylindrical in cross section; pile sparse, semi-ap- pressed in most species; tomentum sparse, usually silvery along sides of fe- males, covering all of doreum in males of most species {B. pavida males lack this feature). Ground color often dark brown or black. Male Terminalia (Fig. 128-135). — Segment 8 from slightly to greatly re- duced; sternite 8 (Fig. 134) a rounded sclerite, notched on the posterior margin ; tergite 8 from narrowly constricted (as in B. pavida) to broadly constricted (as in B. baccata (Fig. 135) and B. abdotn- inalis). Epandrium (Fig. 131) of mod- erate size, usually wider than long, ratio of length/width along midlines from 0.7 to 1.0; posterolateral margins not modi- fied; cerci as long as to considerably shorter than ventral epandrial sclerite and usually free from one another; ven- tral epandrial sclerite (Fig. 132) simple, often notched apically, usually relatively large with respect to cerci ; interseg- mental membrane basad of ventral epan- drial sclerite weakly sclerotized, with small, lateral shields fitted into postero- ventral portion of epandrium in soine species and not, or at most vei"y weakly, connected to anterior margin of aedeagus. Gonoco.xites (Fig. 128) free over entire length, usually simple in form, but in some species elongate posteriorly; hy- pandrium small, thin, free, bridgelike, attached to both gonocoxites by mem- branes; aedeagus attached to ventral lobes of gonoco.xites; parameral process absent or very minute; parameral apodeme attached to lateral margin of aedeagus by a thin, transparent mem- brane; ventral lobes of moderate size (small in a few West Indian species). 234 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 weakly attached to center of aedeagus; gonostylus usually elongate, curved dor- sad, and with a tuft of setae on extreme posteroventral portion in a few species; gonostylus reaches beyond (posteriorly) distiphallus and, in most species, beyond gonocoxite extensions; ratio of aedeagus basad of center/distad of center, usually 0.67-0.80, in a few cases 1.0-1.4 (e.g., B. ahdominalis) ; ratio of width of phallus base/width of dorsal apiodeme, 0.15-0.44, most North American species ranging between 0.3 and 0.4. Aedeagus variable, usually of moderate size; distiphallus short (as in B. abdominalis) to long [as in B. sericeifrons (Krober 1928a: 34) from Chile], with those of most North American species of moderate length ; distiphallus simple, downcurved apically; ventral apodeme short, broader at base than at apex, shorter than dorsal apodeme, and usually shorter than ejac- ulatory apodeme, in B. abdominalis very broad and forked apically; dorsal apo- deme shieldlike, broader apically than basally, generally more heavily sclero- tized along lateral margins; distal end of ejaculatory apodeme club shaped, in B. abdominalis very large, triangular. Habitat Many of the species inhabit dry can- yons in Mediterranean zone vegetation ; others are found along beach areas in and amongst dune vegetation. Species of Brachylinga are not found in extreme deserts but are often associated with mar- ginal desert habitats. Distribution Brachylinga occurs throughout much of the drier zones of the Nearctic and Neotropical regions. One group is found in the southwestern USA and western Mexico, another in Chile, Peru, and Ecuador; yet another is found in the West Indies and Florida. Included Species abdominalis (Fabricius) 1805:12 [Bi- bio) , new combination. Distribution. — Puerto Rico, West Indies. vexans (Curran) 1926:2 3, 9 [Psilocephala] . new s\Tionym. baccata (Coquillett) 1893b: 226 S, 9 (Psilocephala) , new combination. Distribution. — California. cinerea (Cole) 1923a: 65 3, $ [Psi- locephala], new combination. Dis- tribution. — New Mexico. monensis (Curran) 1926:2 9 [Psilo- cephala), new combination. Distri- bution. — Mona Island, \Vest Indies. morata (Coquillett) 1893fc:225 3, 9 [Psilocephala) , new combination. Distribution. — New York, New Jer- sey, Florida. obscura (Coquillett) 1893fe:229 9 [Psilocephala) , new combination. Distribution. — Jamaica, West In- dies. pavida (Coquillett) 1893b: 226 3 [Psilocephala) , ne\v combination. Distribution. — Arizona, California: Baja California, Mexico. pilosa (Krober) 1914:47 3 [Psilo- cephala], new combination. Distri- bution. — Arizona. platycera (Loew) 1872:114 9 [Psilo- cephala], new combination. Distri- bution. — Cuba, \Vest Indies. laticornis (Loew) 1869a: 10 9 [Psilocephala] , not Loew 1856. ? slossonae (Coquillett) 1893b: 227 9 [Psilocephala slossoni) emendation. new combination. Distribution. — New Hampshire. slossoni (Coquillett), improper original spelling. squamosa (Hardy) 1943:24 3, 9 [Psilocephala) , new combination. Distribution. — Key W'est, Florida. tepocae (Cole) 1923b: 461 9 [Psilo- cephala), new combination. Distri- bution. — Sonora, Mexico. More than 10 species of Brachylinga are undescribed, and several species are described from South America. Genus Litolinga Irwin & Lyneborg, new genus (Fig. 16, 17, and 136-141) Feminine Derivation of name: litos (Greek") = simple; linga (Sanskrit) = penis. Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 235 Fig. 136-141. — lilolinga ocula (Adams) male lerminalia. 136. — Left gonocoxile with appendages and aedeagus in dorsal view. 137. — Left gonocoxite with appendages in ventrolateral view. 138. — Epan- drium with appendages in dorsal view. 139.— Aedeagus in loteral view. 140. — Tergite 8. 141. — Slernite 8. Scale: 0.5 mm. Type-species: Psilocephala acuta Adams 1903 : 222 by present designation. Type- locality: Englewood, Clark County, Kansas. i Diagnosis Small- to medium-sized, usually slen- der species. Head. — Compound eyes of male al- most touching for a considerable dis- tance; eyes of male of two distinct facet sizes, with a linear indentation on eye surface where different facet sizes meet. Frons of female (Fig. 17) extremely wide, more than 3X width of ocellar tubercle at level of antennal insertion and more than 2X width of ocellar tubercle at vertex. Frons of male has light to dark brown velvety patch con- tiguous with each compound eye ; frons sf female usually has distinct rounded, dark brown velvety spot contiguous with ;ach compound eye (one undescribed iperies from Texas has minute crescent- ihaped velvety patches) . Frons and face ii both sexes completely tomentose ; to- nentum buff to brown; frons and upper ace of male without pile or setae; frons of female has scattered, sparse, short setae above velvety spots, otherwise up- per face and frons without pile or setae. Genae protrude as lobes below compound eyes (Fig. 16), always with a patch of darker brown tomentum running to sub- cranial cavity. Head triangular in shape when viewed from side, with ocelli form- ing upper point, base of genae a second and antennal insertion a third, with an- tennae placed very low on head. Ocellar tubercle has many short setae angled forward, originating mainly from pos- terior portion. Head 0.6-0.8X as deep as antennal length; scape of male 0.4— 0.5 X as long as flagellum; scape of fe- male 0.5-0.6 X as long as flagellum. Scape stout; first flagellomere exagger- atedly pear shaped with a longer termi- nal style composed of a single segment plus a blunted apical spine. Palps one segmented although on some specimens they may ajjpear to be two segmented. Thorax. — np 3, sa 1-2 (usually 2), pa 1, dc 0, sc 1-2; all thoracic setae dark brown to black ; mesonotal pile of both sexes pale, mostly silvery, appressed, sparse in general ; prostemum with elon- 236 Illinois Natural History Survey Bulletin Vol. 32. Art. 3 gate white pile in and around central depression. Wing.— Cell nis widely open ; ratio of lengths R4/R5 0.93-1.05; cell u 2.0-2.8X longer than wide at apex; wings generally have mottled brown patches between veins, amount of dark- ened area differs between species. Legs. — Fore coxa has 2 large, black setae on anterior surface, 1 apical, the other about midway between apex and base of coxa; hind femur has 3-7 anteroventral setae. Abdomen.— Rather slender, gradually tapering from segment 2 toward apex; abdominal segments not telescoped ; male dorsum flattened, most species have a patina of fine silvery tomentum; ground color dark to light brown. Male Terminalia (Fig. 136-141). — Tergite 8 only moderately constricted in middle (Fig. 140) ; stemite 8 a small, nearly circular sclerite (Fig. 141). Epan- drium (Fig. 138) about % as long as wide along midline, with sharp posterolateral comers extending nearly to level of pos- terior margin of ventral epandrial scler- ite; cerci extend slightly beyond ventral epandrial sclerite; ventral epandrial sclerite simple, about 2 X as long as cerci, posterior margin incised in several spe- cies; sclerotization of intersegmental membrane anterior of ventral epandrial sclerite weak, connecting this sclerite with anterior margin of aedeagus; sclero- tization of intersegmental membrane does not reach posterolateral portion of epan- drium. Gonocoxites (Fig. 136) free for their entire distance; hypandrium free, small, bridgelike, connecting gonocoxites; parameral process present as a short finger; parameral apodeme weak, not at- tached to aedeagus; ventral lobes of gonocoxites relatively large, lightly sclero- tized, and weakly attached to ventral cen- ter of aedeagus; gonostylus elongate, twisted toward distiphallus, usually blunt ; ratio of aedeagus basad of center/distad of center about 2/1 ; ratio of width of phallus base/width of dorsal apodeme 1/4. Aedeagus (Fig. 136 and 139) large, distiphallus simple, short, downward curved; ventral apodeme thin, short, bladelike, about % as long as dorsal apodeme. not entirely covering ejacula- tory apodeme; dorsal apodeme generally covers ejaculatory apodeme ; anterior end of ejaculatory apodeme clublike, enlarged, though dorsoventrally flattened. Habitat Specimens of Litolinga have been col- lected in the beach sands of the Gulf of Mexico and inland in sand dunes of Kan- sas and Texas. Lar\ae of one species, L. acuta (Adams), are known predators of Elasmopalpus Ugnosellus (Zeller), the lesser com stalk borer, on peanuts in Texas (Johnson 1978). Distribution Litolinga is restricted to the south- eastern and south-central United States (Florida, Kansas, Texas) and along the eastern coast of Mexico (Tamaulipas, \'era Cruz) . Included Species acuta (Adams) 1903:222 5, 2 {Psi- loccphala) , new combination. Dis- tribution. — Kansas, Texas. pallida (Krober) 1914:45 S {Psi- loccphala) , new combination, new synonym. ? bolboccra (Osten Sacken) 1887:162 9 {Thcrcva), new combination. Distribution. — Presidio, Me.xico. (From the description, the species seems to belong within Litolinga.) holhoceras, Krober 1914:64, error in spelling. tergisa (Say) 1823:39 3 {Thcrcva), new combination. Distribution. ^ Florida. tcrgissa, LeConte 1859 : 57. unjusti- fied emendation. corusca (Wiedemann) 1828:232 S {Thereva) Cole 1923a: 71. There aie about three undescribed species. Genus Rhagiofoniia Irwin & Lyncborg, new genus (Fig. 23 and 142-147) Feminine Derivation of name: Rliagio, a genus ol flies; forma (Latin) = shape, form. Type-species: Psilocephala macidipennis 1 I Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 237 Krober 1914:45 by present designa- tion. Type-locality: San Jose del Cabo, Baja California, Mexico. Diagnosis Moderately large-sized, slender species. Head.— Frons of male at its narrow- est much narrower than half width of anterior ocellus; frons of female at level of anterior ocellus 2.0-2.2X as wide as ocellar tubercle; male frons raised, with brownish-gray tomentum and long, black pile over entire surface; female frons has brownish-gray tomentum, unpattemed, slightly concave in middle, and has short, appressed pile on upper two-thirds ; head rather prominently protrudes anteriorly at antennal level; head depth 1.2-1.4X antennal length (Fig. 23) ; scape slender, 0.6-0.8 X as long as flagelluin; first flagel- lomere constricted at base; flagellar style long, slender, two segmented, with a dis- tinct, terminal spine; palps one seg- mented. Fig. 142-147. — Rbagioforma maculipennis (Krob.) male terminalia. 142. — Right gonocoxite with appendages and aedeagus in dorsal view, 143. — Epandrium with oppendages in dorsal view. 144. — 'Epondrium with appendages in ventral view. 145. — Aedeagus in lateral view. 146. — Tergite 8. 147. — - Sternite 8. Scale: 0.5 mm. 238 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 Thorax. — np 3-4, sa 2, pa 1, dc 2, sc 2; mesonotal pile of male long, dense, erect, that of female much shorter and more appressed; presternum has long pale pile in and around central depression. Wing. — Cell m, open or closed at wing margin; vein R* much longer than vein Rs ; cell Ft about 2 X longer than wide at apex; wing grayish-brown with pattern formed by dark shadows around cross- vein and distal portion of longitudinal veins; stigma dark brown. Legs.— Fore coxa has 2 strong black setae: 1 apical on anterior surface and 1 subapical on exteroanterior margin; hind femur has 5-7 anteroventral setae, a few postero- ventral setae. Abdomen.— Rather slender and grad- ually tapering from base toward apex; dorsum noticeably convex in both sexes; dorsum of male entirely tomentose and pilose ; tomentum silvery gray, pile white ; dorsum of female yellowish brown, with black spots in midline, pile sparse and very short, strongly resembling the ab- dominal pattern found in many species of Rhagio F. Male Terminalia (Fig. 142-147). — Tergite 8 (Fig. 146) large and strongly constricted along middle; stemite 8 (Fig. 147) very large, broadly oval, with semi- circular incision posteriorly; epandrium (Fig. 143) shorter in midline than wide, with pointed, projecting, posterolateral corners; cerci free (Fig. 143), well sep- arated and sclerotized, sparsely haired, large; ventral epandrial sclerite (Fig. 144) extends slightly beyond cerci, pos- terior margin cleft, anteriorly reaching only to level of middle of epandrium, the anterior part separated along midline and from part below cerci: parameral apodeme without attachment to aedea- gus; distiphallus (Fig. 142) wide proxi- mally and gradually tapering, in lateral view (Fig. 145) only slightly curved: dorsal apodeme (Fig. 142) long, oval: ventral apodeme shaped like a very nar- row spoon; ejaculatory apodeme (Fig. 142) small, with distal part expanded: ventral lobes of gonocoxite (Fig. 142) large, lamellate, loosely attached to ven- tral surface of aedeagus; parameral pro- cess absent, but parameral apodeme well developed, short and thick; gonocoxites not united ventrally, only attached by a weak membrane anteriorly; hypandrium (Fig. 142) present, free. Habitat Unknown. One female was taken drinking from a small stream in an other- wise dry area in northern Baja California. Distribution The genus Rhagioforma is apparently restricted to Baja California, Mexico. Included Species maculipennis (Krober) 1914:45 $ (Psilocephala), new combination. Distribution. — Baja California, Mexico. No undescribed species of this genus are knov^m. Genus Arenigena Irwin & Lyneborg, new genus (Fig. 19, 21, and 148-156) Feminine Derivation of name: arena (Latin) = sand; gena (Latin) = bom in. Type-species: Thereva semitaria Coquil- lett 1893a: 198 by present designation. Type-locality: Southern California. Diagnosis Medium-sized, slender to moderately broad species. Head. — Eyes in male (Fig. 19) abso- lutely touch for a rather long distance; frons of female at level of anterior ocellus about twice as wide as ocellar tubercle and only slightly widens toward bottom of eyes; frons in both sexes entirely to- mentose, not patterned, with at most a few hairs on the upper frons of female; head only very slightly protrudes anteri- orly; gcna has very short, pale pile; head depth 1.5-1.7 X antennal length (Fig. 21): scape slender. 0.5-0.9 X as long as flagellum : flagellar style two seg- mented, with a distinct terminal spine; palps one segmented. Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 239 Thorax.— np 3, sa 2, pa 1, dc 1-2, sc 2; all thoracic setae pale; mesonotal pile in both sexes of two types: one is long, appressed, pale, scalelike, and the other is short, erect and pale or dark; prostemum has long, whitish pile in and around central depression. Wing. — Cell ma closed; veins Ri and R5 equal in length; cell r^, 1.9-2.1 X as long as wide at apex. Legs.— Fore coxa usually has 3 setae on anterior surface: 2 on apical half and 1 on basal half of anteroexterior margin, the latter rarely missing; hind femur has 6-8 anteroventral setae. Abdomen. — Rather slender, gradu- ally tapering posteriorly from segment 2 ; male dorsum convex or somewhat flat- tened, densely covered with whitish-gray tomentum and whitish pile; female dor- sum yellowish, subshiny, frequently with Fig. 148-156. — Arenigena spp. 148-155.— A. semilaria (Coq.) mole terminalia. 148. — Gonocoxites with appendages (left gonostylus omitted) and hypandrium In ventral view. 149. — Rigiit gonocoxite with appendages and aedeagus in dorsal view. 150..— Left gonocoxite in lateral view. 151. — Aedeagus in lateral view. 152. — Epandrium with appendages in dorsal view. 153. — Epandrium with appendages in ventral view. 154. — Tergite 8. 155. — Slernile 8. 156. — A. morcida-group right gonocoxite with ap- pendages and aedeagus in dorsal view. Scale: 0.5 mm. 240 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 grayish to grayish-brown anterior bands on anterior segments. Male Terminalia (Fig. 148-156). — Tergite 8 (Fig. 154) comparatively large and constricted for rather a short dis- tance in middle; stemite 8 (Fig. 155) also rather large, oval, in some species with a low, wide incision along midpoint of posterior margin; epandrium (Fig. 152) shorter in midline than wide, with short, rounded posterolateral comers; cerci free, rather weakly sclerotized; ven- tral epandrial sclerite (Fig. 153) large, often e.xtending beyond cerci, tapering anteriorly and reaching to anterior mar- gin of epandrium, where folded 180° and attached to anterior margin of aedeagus, this attachment markedly well sclerotized; parameral apodeme has a weak, membranous attachment to aedea- gus in semitaria (Fig. 149), a more sclerotized attachment in the marcida group (Fig. 156); aedeagus (Fig. 151) has gradually tapering, curving disti- phallus, broad, rectangular to ovoid dor- sal apodeme, short, simple ventral apodeme, and short ejaculatoiy apodeme that widens slightly distally; ventral lobes of gonocoxites (Fig. 148) weakly sclero- tized, without a distinct attachment to ventral surface of aedeagus; parameral process (Fig. 149 and 156) present and variously modified distally; parameral apodeme short; gonostylus hook shaped, sometimes with an apical comb of setae; gonocoxites (Fig. 148) in ventral view attached by a rather wide membrane in midline, this membrane continuing pos- teriorly into weakly sclerotized ventral lobes, each gonocoxite being clearly de- marcated; hypandrium (Fig. 148) free as a narrow, well-marked sclerite along the anteroventral comers of the gonocox- ites. Habitat Species of Arcnigena are found in desert habitats with sparse vegetation and sandy substrates; specimens have been taken from desert washes. Distribution Arenigena is a desert genus, found from Idaho into Mexico and from Cali- fomia eastward to Colorado, New Mex- ico, and Texas. Included Species brunnea (Krober) 1914:46 9 {Psilo- cephala), new combination. Distri- bution. — Arizona. marcida (Coquillett) 18936:228 $ (Psilocephala) , new combination. Distribution. — Southern Califomia. semitaria (Coquillett) 1893a: 198 $, 9 [Thereva] , new combination. Distribution. — Southem California. Several undescribed species occur in this genus. Genus Ammonaios Irwin & Lvneborg, new genus (Fig. 20, 22, and 157-161) Masculine Derivation of name: ammos (Greek) = sand; na/o (Greek) = to dwell. Type-species: Thereva nivea Krober 1914:64 by present designation. T\-pe- locality: Mesiila Valley, New Mexico. Diagnosis Moderately large, heavy-bodied spe- cies. Head. — Frons of male (Fig. 20) at its narrowest distinctly narrower than half width of anterior ocellus; frons of ' female at level of anterior ocellus 2.1- 2.4X as wide as ocellar tubercle; male frons has whitish tomentum and whitish, scaly pile; female frons has entirely pale tomentum, not markedly patterned, and like male has appressed, pale, scaly pile: head only slightly protiiides at antennal level: lateral portion of face and gena has scaly pile; facial and genal call! absent; head depth 1.4-1.8 X antennal length (Fig. 22); scape slender, 0.3-0.6X as long as flagellum; flagellar stvle apical, two segmented, with a distinct temiinal spine ; palps one segmented. Thorax. — np 3-5, sa 1-2, pa 1, dc 1-2, sc 2; all setae slender and pale; mesonotal pile in both sexes dense, uni- form, pale, mostly scaly, and semi-ap- pressed to appressed; prostemum has long, whitish pile in and around central depression. Wing. — Cell m^ closed ; veir. Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 241 Fig. 157—161. — Ammonaios niveus (Krob.) male terminalia. 157. — Right gonocoxite with append- ages and aedeagus in dorsal view. 158. — Gonocoxites with appendages and hypandrium in ventral view. 159. — Epandrium with appendages in dorsal view. 160. — Tergtte 8. 161. — Sternite 8. Scale: 0.5 mm. R4 longer than vein R5; cell r4 1.9-2.OX as long as wide at apex; color uniformly hyaline, pale brownish, or with a whitish tinge; stigma pale or dark brownish, or costal margin more extensively darkened. Legs. — Fore coxa with 2 pale, slen- der apical setae on anterior surface, sometimes an additional seta more basally; middle coxa has whitish scaly pile on posterior surface; hind femur has 2-8 pale to dark anteroventral setae. Abdomen. — Rather broadly built, in both sexes gradually tapering from seg- ment 3 to apex ; dorsum flattened in both sexes; male dorsum entirely covered with thick, long, appressed, scaly whitish pile that completely covers integumental sur- face; female dorsum yellowish brown to grayish yellow, with ill-defined, darker anterior bands on anterior segments ; pile much sparser and shorter than on male. Male Terminalia (Fig. 157-161). — Tergite 8 (Fig. 160) and sternite 8 (Fig. 161) large. Epandrium (Fig. 159) shorter in midline than wide, postero- lateral comers rather sharply pointed ; cerci free, rather weakly sclerotized, never extending beyond ventral epan- drial sclerite; ventral epandrial sclerite (Fig. 159) very wide, more or less strongly extending beyond cerci, and more or less ventrally directed; ventral epandrial sclerite reaches anterior mar- gin of epandrium and has a membran- ous attachment to aedeagus; parameral apodeme has a more or less distinctly sclerotized bridge to dorsal apodeme of aedeagus; aedeagus has a long, narrow, downcurved distiphallus; dorsal apodeme tapers distally; ventral and ejaculatory apodemes small; ventral lobes of gono- coxites short and weak, not attached to aedeagus; parameral process large and stout, often slightly spoon shaped; para- meral apodeme stout; gonostylus vari- ously shaped; gonocoxites short, tnancate distally, ventrally (Fig. 158) attached by a membrane; hypandrium narrow and laterally fused to gonocoxites. Habitat Species in the genus Ammonaios are inhabitants of very xeric zones and can be found as adults on and near shifting 242 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 sand dunes. Larvae have been reared from sand taken from areas near vegeta- tion in shifting dunes. This genus is not known to occur in coastal areas and seems restricted to inland dune systems. Distribution Southwestern United States (Oregon, California, Idaho, Utah, Nevada, Ari- zona, New Mexico, Texas) and northern Mexico (Baja California, Sonora, Chi- huahua, Coahuila) . Included Species niveus (Krober) 1914:64 $ {The- reva nivea) , new combination. Dis- tribution. — New Mexico. At least four additional, unnamed spe- cies are at hand. Genus Megalinga Irwin & Lyneborg, new genus (Fig. 3 and 162-168) Feminine Derivation of name: megas (Greek) = large; linga (Sanskrit) = penis. Type-species: Megalinga insignata Irwin & Lyneborg, herein described, by pres- ent designation. Type-locality: Death Valley, California. Diagnosis Medium- to large-sized, slender to moderately broad species. Head. — Frons of male at its narrow- est narrower than half width of anterior ocellus, or eyes tangential; frons of fe- male at level of anterior ocellus from 2 to nearly 3X as wide as ocellar tubercle, gradually widening downward to bot- tom of eyes; frons has entirely grayish tomentum, either without distinct pat- tern or with two small, dark tomentose. circular areas on lower frons at eye mar- gin; male frons without pile; female frons has sparse, short, black, semi-ap- pressed pile on upper two-thirds; head moderately protrudes anteriorly; face without pile; genae ridge shaped, with darker tomentum than rest of head and short, black pile; head depth 1.4-1.7 X antennal length; scape slender, 0.4—0.6 X as long as flagellum; flagellar style two segmented with a distinct terminal spine; palps one segmented. Thorax.— np 3, sa 2, pa 1, dc 1-3, sc 2; mesonotal pile mostly short, semi- appressed to appressed, pale: additional sparse pile of very short, black, erect hairs sometimes occurs on midanterior portion; prostemum has long whitish pile in and around central depression; each cervical lobe anterior to prostemum has a strong, black seta ( Fig. 3 ) . Wing. —-Cell ma open; vein R2 + 3 has a deep curve apically; vein R4 longer than vein R5; cell ri 1.6-1.8X as long as wide at apex; whitish-hyaline, with strongly marked pattern of dark brownish patches. Legs.— Fore coxa has 2 stout setae on apical half of anterior surface and an additional stout seta near base on antero- exterior margin; hind femur has 5-6 an- teroventral setae, some shorter postero- ventral setae, often arranged in a close group near apex. Abdomen.— Rather narrow, gradu- ally tapering from base to apex: dorsum convex, especially in male; dorsum of male has pale grayish tomentum; dor- sum of female yellowish to brownish, due to thinner tomentum, and not distinctly patterned. Male Terminalia (Fig. 162-168). — • Tergite 8 (Fig. 167) about as wide as epandrium and greatly constricted in middle; stemite 8 (Fig. 168) rather large, with broad incision in posterior margin; epandrium (Fig. 162) shorter in midline than wide, its posterolateral cor- ners broadly rounded, with a broad, in- folded margin; cerci (Fig. 162) free, strongly sclerotized, not extending beyond ventral epandrial sclerite ; this sclerite large, reaching to anterior margin of epandrium, not attached to anterior mar- gin of aedeagus, entirely membranous, only a hoi-seshoe shaped sclerotized area (Fig. 166) below cerci; aedeagus has two attachments (Fig. 164) to parameres and gonocoxites: a long, weak, membranous bridge stretching from distal corners of dorsal apodeme to midsection of para- mere, and a stronger attachment between ventral lobes of gonocoxites and ventral V Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 243 surface of aedeagus; aedeagus (Fig. 164 270°, its apex being deeply cleft; ventral and 165) of a very remarkable shape; apodeme arises at a right angle from base distiphallus forms a right angle with of distiphallus, extending parallel to dor- die heavily sclerotized, rectangular dorsal sal apodeme, but much narrower and apodeme and curves downward for about shorter; ejaculatory apodeme about as Fig. 162—168.— Megaiinga insignala Irw. & Lyn. male terminolia. 162. — Epandrium with append- ages in dorsal view. 163. — Gonocoxites with appendages in ventral view. 164. — Right gonocoxite with appendages and aedeagus in dorsal view. 165. — Aedeagus in lateral view. 166. — Ventral epandrial sclerite and cerci in ventral view. 167. — Tergite 8. 168. — Sternite 8. Scale: 0.5 mm. 244 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 long as ventral apodeme and very slender. Ventral lobes of gonocoxites (Fig. 163) very large, attached in midline for a long distance, and also attached to body of aedeagus; parameral process very long and slender, but its apodeme very re- duced; gonocoxites (Fig. 163) in ventral view attached by a strong membrane over midline but a ventral synsclerite is not formed, as each gonocoxlte is clearly de- marcated by a strongly sclerotized and pigmented inner margin; a similar strong membrane attaches the ventral lobes for a long distance; a free hypandrium is not present, but a hypandrial element may enter into the fusion of the antero- ventral corners of the gonocoxites. Habitat The two species listed below occupy distinct habitats, one in the deserts of the southwestern United States, the other in the coastal dunes and beaches of southern Mexico, Guatemala, and El Salvador along the Pacific Ocean. Distribution This genus is apparently restricted to the deserts of the southwestern United States and the coastline of Sinaloa, Mex- ico, southward to El Salvador. Included Species insignata Irwin & Lyneborg, described below. Distribution.— Southern Cal- ifornia, Arizona, and northern Baja California. One undescribed species of Mcgahnga is known from Sinaloa, Nayarit, and Guerrero, Mexico, and Ahuachapan, El Salvador. Megalinga insignata Irwin & Lyneborg, new species Derivation of name: in (Latin) = not; signatus (Latin) ^ mark. Description See Table 1 for selected measurements of the holotype and most paratype ma- terial. Male, holotype, specimen number 5144^, 8.96 mm in length, excluding antennae. Ground color pale tan overall; pile generally short, but longer on genae, lower occiput, and laterally on abdomen ; all pile whitish to pale yellow: tomentum silver to golden, moderately dense. Head. — Frons narrow, the eyes large, diverging only slightly from middle of frons toward genae; eyes at their closest separated by about half the width of the anterior ocellus. Pile lacking on frons and face, long on occiput and rather dense on lower occiput; genae flanged, enlarged, with short dark brown hairs on ventral surface. Ocellar triangle prominent, with about 12 short, blackish bristles; occiput has a single row of postocular setae, 11 on each hemisphere. Tomentum very fine, brownish golden centrally and grayish silver laterally on frons and face; genae have dark brown tomentum; occiput has white tomentum: frons has two minute, crescent shaped marks of brown tomen- tum, one tangential to each eye. Anten- nae tan to yellowish-tan; scape has a single large black seta projecting antero- dorsally from dorsal surface and 2 such setae projecting anteroventrally from ven- tral surface; pile whitish, rather short on scape and pedicel, black, very short on basal third of flagellum: tomentum fine, whitish on scape and pedicel, thinner on flagellum; scape slightly longer than wide; pedicel about half as long as wide: flagellum about 2.5 X longer than wide, exaggeratedly pear shaped; style com- posed of two subsegments plus terminal spine, basal subsegment short, apical sub- segment about 2X as long as basal sub- segment, teiTninal spine short, blunt. Proboscis browTi, large, reaching almost to base of antennae; palps yellowish, reach about three-fourths distance to apex of proboscis, one segmented though with a deep constriction about one-fourth distance from base to apex. ' Each specimen has been assigned a unique number to facilitate the association of data. This number appears below the specimen on a separate yellow label bearing, besides the number, the words, THEREVIDAE/M.E. IRWIN/SPECIMEN #. i Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 245 lO Oh CH-;i, n — n in Oh 02 « m Oh o PJ 10 '^ 00 nj 10 Cl, 10 246 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 Thorax. — Mesonotal vittae rather indistinct; tomentum silver grayisii, rather dense, covering all of mesonotum, scutellum, and pleural areas; pile short, appressed, dense on and near scutellum, white with a few golden tan patches along anterior part of faint narrow vit- tae on mesonotum. Mesonotal macro- setal pattern: np 3, sa 2, pa 1, dc 2, sc 2, black. Pile tliin, white, elongate, con- fined for the most part to anepistemum, pleurotergite, and coxae. Wing. — Veins yellowish brown with darker patches in several areas: at fork R4 + 5, along veins R4 and R5, near tip of R2+3, along vein R2+3 below darkened stigma, along most crossveins (not humeral crossvein), and thinly along veins Mj, M2, and M3. Veins M3 and M4 do not meet, distance be- tween them at wing margin 0.16 mm; vein R2 + 3 curves dorsally at tip; vein R4 exaggeratedly sinuate; halter very pale tan overall. Legs. — Legs yellowish brown; femora have white, mostly ap- pressed pile, scalelike dorsally; femoral setal pattern: fi 3 av; f2 2 av, 1 pv; fa 4 av, llpv. Tibial setal pattern: ti 3 ad, 4 pd, 4 pv; t2 2 ad, 4 av, 3 pd, 3 pv; ta 7 ad, 6 av, 4 pd, 4 pv. Fore coxa has 3 prominent, black setae, 1 basal and 2 apical. Abdomen. — Yellowish brown with silver gray tomentum and white pile; fascia slightly differentiated by a more tanish tomentum. Male Terminalia. •— Very large, darker brown than abdomen. See generic description for description of male ter- minalia. Varl^tion of Males in Paratvpe Se- ries.— Mean length, excluding anten- nae, 9.13 mm ± standard deviation of 0.28 mm. Measurement differences are presented in Table 1. Femoral setal pat- tern: fi av 3-4, pv 0-1; f2 av 1-4, pv 1—3; fs av 4-6, pv T-IL Tibial setal pat- tern: ti ad 3-5, av 0, pd 3-4, pv 2-4; to ad 2^, av 2-4, pd 3-4, pv 3-5; U ad 4-9, av 4-8, pd 3-8, pv 2-6. Variation of Females in Paratype Series.— Mean length, excluding anten- nae, is 11.30 mm ±: standard deviation of 0.92 mm. Females are significantly (at 1 -percent level) larger than males. Table 1 presents selective measurements of fe- male paraty^ses. Females are similar to males except as follows: females have less dense tomentum and less dense pile overall. Frontal differences are great, as can be seen from Table 1 ; upper frons has sparse, short, black setae; a pair of small half crescent dark brown spots, one tangential to each eye, occur at the junction of upper and lower frons; a slightly darker tan strip of tomentum connects eye margin and antennal inser- tion. Femoral setal pattern: fi av 2-6, pv 0-2 {5151 has pd 1 ) ; f, av 3-5, pv 2-5; fa av 4-8, pv 6-9. Tibial setal pat- tern: ti ad 3-4, av 0, pd 2-5, pv 4; ta ad 3-4, av 2-3, pd 3-4, pv 3-4; ta ad 6-10, av 6-9, pd 4-7, pv 4-7. Female Terminally. — Tergite 8 rather large, squarish, wdth a transverse band of black setae about midway from anterior to posterior ends; stemite 8 elongate, a similar band of black setae about one-third distance from base to apex, widi a small central hump covered with small setae centrally along posterior margin, without any incisions on pos- terior margin; vaginal apodeme (stemite 9) a complete sclerotized, elongate ring, taking up most of space abo\e stemite 8, with a thin sclerotized connection posteriorly to tergite 9 and an extraor- dinary sclerotized structure involving the sclerotization of the spermathecal duct and a triangular sclerotized apparent apex of the duct that might represent a united spermathecae (Irwin 1976) ; in- tersegmental membrane connecting ster- nite 8 and vaginal apodeme heavily sclerotized, containing 2 sclerites united along midline of stemite 8 and connected to lateral portion of sclerotized ring of vaginal apodeme. Tergite 10 has about 8 thickened spines in the posterodorsal position, and tergite 9 has about 6 diin- ner, longer spines in the posteroventral position; some finer setae anterior of posterodoreal spines on tergite 10: cerci widely separated, have a dense patch of Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 247 black setae, connected to one another by a transparent membrane; subanal plate pointed apically, fitted beneath tergites 9 and 10 and does not extend posteriorly beyond cerci. Specimens Examined Holotype : $ , 5144, California Acad- emy of Sciences type number 13670; Bennetts Well, Inyo County, California; 30 March 1952; on indefinite loan from the California Insect Survey, University of California, Berkeley; A. E. Michel- bacher, collector. Paratypes: 5 males, 12 females from these localities: MEXICO: Baja California Norte: Bahia de los Angeles, 1 April 1973, J. T. Doyen & J. A. Powell, ? , 5151 (CIS to CIS).i UNITED STATES: Arizona: Mari- copa County: Tempe, 8 May 1964, F. F. Hasbrouch, $, 5150 (ASU to ASU). California: Imperial County: Brawley, 14 April 1959, E. I. Schlinger, 9 , 5146 (EIS to UCR). Riverside County: Coa- chella, 25 May 1938, E. C. VanDyke, 9 , 5147 (CAS to CAS) . San Bernardino County: Needles, 3 May 1964, P. Tor- chio & G. Bohart, S, 5149 (USU to USU) ; 9 air miles south of Baker at Zzyzx Springs, 24 April 1977, C. T. Kitayama ( malaise trap ) , $,5134 (CIS to MEI), 9, 5135 (CIS to CIS), 5136 (CIS to UCD) ; same data, 25 April 1977, 9 , 5137 (CIS to MEI) ; same data as last except, G. W. Ulrich, 9 , 5138 (CIS to USNM) ; same data, 26 April ^ Specimen loan institutions and deposi- tories (abbreviations in parentheses) : Arizona State University, Tempe (ASU); California Academy of Sciences, San Francisco (CAS) ; California Insect Survey, University of Cali- fornia, Berkeley (CIS) ; Canadian National Collection, Ottawa (CNC) ; Illinois Natural History Survey, Urbana (INHS); M. E. Irwin Collection (MEI); Evert I. Schlinger Collection (EIS) ; University of California, Davis (UCD) ; University of California, River- side (UCR) ; United States National Museum if Natural History, Washington, D.C. (USNM); Utah State University, Provo fUSU); Zoological Museum, Copenhagen, Denmark (ZMC). 1977, M. E. Buegler (hand netted), 9, 5139 (CIS to CNC); same data, 27 April 1977, 9, 5140 (CIS to INHS). Inyo County: Furnace Creek, Death Valley, 27 March 1961, M. E. Irwin, 9 , 5141 (MEI to ZMC) ; same data, D. R. Miller, 9, 5142 (UCD to MEI) ; same data, 8 April 1939, E. G. Linsley, $, 5143 (CIS to CIS) ; Bennetts Well, Death Valley National Monument, 15 April 1968, J. Bigelow & M. A. Cazier, 9, 5145 (ASU to ASU); Tecopa, 30 May 1955, J. Belkin, $ , 5148 (UCR to UCR). Genus Brevipema Irwin (Fig. 169-175) Feminine Breviperna Irwin 19776:288. Type-spe- cies: Psilocephala placida Coquillett 1894:99 by original designation. Type- locality: Listed as "Florida," appar- ently in error (Irwin 19776:293). Reference: Irwin 19776. Diagnosis Large, robust species. Head. — Frons of male at its narrow- est about as wide as anterior ocellus; frons of female at level of anterior ocellus nearly twice as wide as ocellar tubercle; frons without distinct pattern of to- mentum; pile on lower frons moderately dense, sparse on upper frons, composed of rather long, black hairs; antennae set on low protuberance; facial and genal calli absent; lateral portion of face and gena bare; antennae 0.6-0.8X as long as depth of head; scape 0.8-0.9X as long as flagellum; flagellar style apical with two segments and a teiTninal spine; palps one segmented. Thorax.— np 3-5 (usually 4), sa 2, pa 1-2 (usually 1), do 0-1, sc 1-3 (usu- ally 2) ; mesonotal pile of two types: one is long, scalelike, sparse, semi-ap- pressed, and the other is short, thin, erect, sparse : prostemum has pile in and around central depression. Wing. — Cell ms open or closed; vein Rj longer than vein Rs; cell t^ about 2X as long as wide 248 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 at apex; color hyaline with dark brown stigma. Legs. — Fore coxa has 2 apical setae on anterior surface; middle coxa without pile posteriorly; hind femur has 7-9 anteroventral setae. Abdomen. — Broad, nearly parallel sided from segments 1 through 3, there- after, abdomen tapers shai-ply to apex; segments 5-8 telescoped within segments 3-4 in males; female segments not tele- scoped ; dorsum of abdomen flattened, more so in males than in females; male dorsum densely clothed in silver tomen- tum; female dorsum lacks silver tomen- tum. Male Terminalia.— Tergite 8 (Fig. 175) small and narrowly constricted me- dially; stemite 8 (Fig. 174) small and broadly bilobate; epandrium (Fig. 172) large, covering most of terminalia, dis- tinctly shorter than wide, with f»ostero- lateral margins bidentate; cerci free, ex- tending slightly beyond ventral epandrial sclerites; ventral epandrial sclerite (Fig. 172) not keeled, not united to anterior margin of aedeagus; parameral apodeme attached by a thickened, wide, nonsclero- tized membrane to dorsal apodeme of aedeagus and ventral lobes broadly at- tached by a nonsclerotized membrane to Fig. 169-175. — Breviperno placida (Coq.) mole lerminalio. 169. — Genitolio in lolerol view. 170. — ' Gonocoxites with appendages and aedeagus in dorsal view. 171.-— Gonocoxites with appendages in \ ventral view. 172. — Epandrium with appendages in venlrol view. 173. — Aedeagus in lateral view. 174. — Sternite 8. 175. — Tergite 8. Scale: 0.5 mm. Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 249 center of aedeagus; distiphallus (Fig. 173) elongate, slender, with an asymetri- cally twisted tip; a nearly closed, sclero- tized ring surrounding proximal portion of ejaculatoiy apodeme is loosely at- tached to ventral lobe; ventral apodeme short and narrow; ventral lobes fused basally, elongate, forming a posteriorly directed continuation to central portion of gonocoxites; distal parameral process reduced, only a basal apodeme existing; gonocoxites (Fig. 171) broadly fused yentrally and flattened; hypandrium ab- sent or completely fused with gonocox- ites, not identifiable. Habitat Breviperna placida inhabits forested mountainous zones, but specific habitats are unknown. Distribution The genus Breviperna is found pre- dominantly in southeastern Arizona. Included Species placida (Coquillett) 1894:99 2 [Psi- locephala). Distribution. — South- eastern Arizona. No undescribed species are known to us. Breviperna milleri Irwin (1977^:294, 9 ) was found to belong to the genus Ozodicero7nya Bigot, based on subse- quent material containing a male. Genus Nebritus Coquillett (Fig. 2 and 176-181) Xebntus Coquillett 1894:98. Type-spe- cies: N. pellucidus Coquillett 1894:98 by original monotypy. Type-locality: Southern California. Zionea Hardy 1938:144 new synonym. Type-species: Z. tanneri Hardy 1938: 144 by original monotypy. Type-local- ity: North Fork, Provo Canyon, Utah. Diagnosis Large- to medium-sized, slender bodied species. Head (Fig. 2) . — Frons of male wide, at level of anterior ocellus 1.6—2.OX as wide as width of ocellar tubercle; frons of female at level of anterior ocellus 2.5- 3.0X as wide as width of ocellar tuber- cle; frons strongly patterned: lower part raised, forming a polished black callus, upper part with brownish to brownish- gray tomentum surrounding the polished black ocellar tubercle; frontal pile very long and erect, extending below level of antennal bases; head prominently pro- tnading anteriorly; antennae set on dis- tinct protuberance; lower frontal callus extends between antennal bases and foiTns an upper midfacial callus below antennae; a polished black callus also located ventrally on face ; upper postocu- lar margin thickened and polished black ; lateral portion of face without pile; gena has long pile; antennae 1.0-1.3 X as long as depth of head; scape 1.2-1.5 X as long as flagellum, slender or thickened; flagellar style subapical, placed in a groove on exterior surface of first flagel- lomere a considerable distance basad of apex; number of segments in flagellar style not discemable without dissection; palps one segmented. Thorax.— np 3-4, sa 2, pa 1, dc 0-1, sc 2; mesonotal pile in both sexes of two types: one is long, erect, black, rich, and the other is moderately long, semi-ap)- pressed to appressed, pale, rich, but largely restricted to lateral parts of meso- notum and to two bands on middorsum; presternum has long pile in and around central depression. Wing. — Cell m^ open; veins R4 and R3 about equal in length or R-, slightly longer; cell Ti 2.5- 3.2 X as long as wide at apex; grayish brown to brown, frequently most in- tensively pigmented along anterior mar- gin or pigment arranged in broad streaks along veins; veins coarse; stigma dis- tinct. Legs. — Fore coxa has 2-3 apical setae on anterior surface; middle coxa has whitish pile on posterior surface ; hind femur has 4-12 anteroventral setae. Abdomen. — Broad at base, gradually tapering from base or from segment 2 to apex, not telescoped ; dorsum flattened, in both sexes dull, with grayish to brownish tomentum, or dorsum subshiny, without any marked pattern. Male Terminaua (Fig. 176-181). — Tergite 8 variable, in the type-species Illinois Natural History Survey Bulletin 177 181 Fig. 176-181. — Nebritus pellucidus Coq. male terminalia. 176.— Right gonocoxite with oppendages and oedeogus in dorsal view. 177. — Gonocoxites with appendages in ventral view. 178. — Epondrium with appendages in dorsal view. 179. — Aedeagus in lateral view. 180. — Sternite 8. 181. — Tergite 8. Scale; 0.5 mm. (Fig. 181) small and strongly constricted medially; sternite 8 (Fig. 180) rectangu- lar to bilobate; epandrium (Fig. 178) only about half as long medially as wide, its posterolateral corners infolded ; cerci rather large, free, well sclerotized, not extending beyond level of ventral epan- drial sclerite; ventral epandrial sclerite large, extending to or nearly to anterior margin of epandrium, with a membra- nous attachment to anterior margin of aedeagus; ventral epandrial sclerite as a whole well sclerotized, keel shaped api- cally below cerci ; parameral apodeme not attached to aedeagus; distiphallus rather long compared with rest of aedeagus, downcurved; dorsal apodeme semicircu- lar, its distal margin with two lateral pro- jections; ventral and ejaculatory apo- demes small, weakly sclerotized: ventral lobes of gonocoxites large, spoon shaped, directed oblicjuely upward, with distinct attachment to ventral surface of aedea- gus; parameral process long and slender, noticeably projecting beyond posterior margin of gonocoxite; parameral apo- deme short; gonocoxites (Fig. 177) not united ventrally except by a membrane; gonocoxite in lateral view broadly rounded posteriorly; hypandrium broad throughout, united with anterior margin of gonocoxites for a rather long distance. Habitat The two described species are found in montane habitats; the one undescribed Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 251 species seems confined to coastal sand dunes. Distribution Western North America. Included Species pcllucidiis CoquUlett \894 -.98 $, 9. Distribution.— Southern California (Monterey, San Luis Obispo, Kern, San Bernardino, Riverside, Los An- geles, and San Diego counties) and Mexico (Baja California Norte) . tanneri (Hardy) 1938:144 5 {Zio- nca) , new combination. Distribu- tion. — Western LInited States (Utah, Nevada, and California) and northwestern Mexico (Baja Califor- nia Norte) . One undescribed species is at hand from the coastal dunes of California (Monterey, San Luis Obispo, Ventura counties) . Note In all basic respects of male terminalia and other obvious synapomorphies, tan- neri conforms to the ground plan of pel- lucidus. These two species are, in our judgment, closely related. Therefore, we have synonymized Zionea with Nebritus. Genus Cyclotelus Walker (Fig. 24, 26, 27, 30, and 182-187) Masculine Cyclotelus Walker 1850:4. Type-species: pruinosus Walker; subsequent designa- tion (Becker 1912:315). Type-local- ity: South America. Furcifera Krober 1911:524, new syno- nym. Type-species: jascipennis (Cole) by subsequent designation (Cole 1960a: 165) (= Cyclotelus socius Walker 1850: 6, new synonym). Type-locality: Brazil. Epomyia Cole 1923a: 26. Type-species: Thercva pictipennis Wiedemann by original designation. Type-locality: Sa- vannah, Georgia. Reference: Cole 1960a [as Furcifera) . Diagnosis Small to rather large species (4.5-13 mm) , moderately slender. Head. — Frons of male at its narrow- est much less than half width of anterior ocellus; female frons (Fig. 30) at level of anterior ocellus 1 .5 X as wide as ocellar tubercle ; head 0.6-0.9X as high as wide, slightly more circular in males; com- pound eyes of female of uniform facet size, of male divided (e.g., pictipennis (Wied.) and rufiventris (Loew) ) or at least with smaller facets ventrally; an- tennal insertion 0.6-0.7 X distance from vertex to genae; frons at antennal in- sertion 0.3-0.4X (females) or 0.2-0.3X (males) as wide as head; genae slightly flanged, dark tomentum contrasting with silvery tomentum of lower face; head hypognathous ; proboscis does not reach antennal base; palps one segmented, 0.7- l.OX as long as proboscis, thin basally, thicker distally, incurved toward tip, densely covered with thick hairs, espe- cially basodorsally and distoventrally; head 0.5-1.1 X as deep as antennal length (Fig. 26 and 27) (North Ameri- can species tend to have antennal length about equal to head depth) ; scape 0.5- 2.0X as long as flagellum (though in the North American species the range is 0.5- 0.7X), 0.1-0.4X as wide as long (range 0.3-0.4X in North American species) ; scape sparsely covered with thin to me- diumly thick hairs; dorsobasal surface of first flagellomere has a few short hairs, basal third more or less constricted, more so in South American species; flagellar style often not entirely terminal, either subterminal (i.e., set on outer lateral portion of apex— usually the North American species) or distinctly aterminal (Fig. 26) (i.e., set on outer lateral por- tion about two-thirds from base of first flagellomere— usually South American species including the type-species) ; style of 1—2 visible segments plus spine, ap- proximately one-tenth as long as first flagellomere; frons lacks (male) or at most has a few short, inconspicuous setae on upper portion (females) ; 10-25 stout, usually darkly colored occipital setae per side in a single row paralleling eye mar- gin from vertex to about one-third dis- tance to bottom of eye, then incurving sharply around a stripe of silvery tomen- 252 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 turn tangential to lower eye margin, and then downcurving for a short distance; pile lacking on frons, face, lateral areas of face and genae, moderately dense, elongate on ventral occiput, generally absent on ventral occipital tomentose stripe tangential to eye margin; tomen- tum fine, powdery, covering most of frons (male) or mainly lower part of frons (female) (Fig. 30), entire face and ven- tral occiput; gena has dark tomentum; upper frons of male has triangle of dark, velvety tomentum; frons of female has a well-defined central patch and often two smaller patches tangential to compound eyes of dark, velvety tomentum; usually area between female velvety tomentose patch and ocellar tubercle shiny, lacks tomentum. Thorax. — np 2-4 (usually 3), sa usually 2 (North American species) or 1 (South American species), pa 1, dc 0, sc usually 2 (North American species) or 1-3 (usually 1, South American species) ; mesonotal pile sparse, moderately short (male) or very short (female), erect, 184 187 185 Fig. 182-187,— Cyclotelus pruinosus Wlk. male terminalia, holotype. 182. — Genitalia in laleral view. 183. — Epondrium with appendages in dorsal view. 184. — Gonocoxites with appendages and aedeagal parts in ventral view, 185. — Left gonocoxite with appendages and oedeogus in dorsal view. 186.— Tergite 8. 187. — Slernite 8. Scale: 0.5 mm. Nov., 1980 Irwin & Lvneborg: The Genera of Nearctic Therevidae 253 occurring over entire surface except scutellum; mesonotal tomentum of two types: one is long, scalelike, semi-ap- pressed, sparse, and the other is pollinose, dense, forming vittae and patterns; scu- tellum has velvety tomentum and often a marginal row of dense, enlarged scale- like tomentum— or pile— in an erect, vertical position ; scutellar setae also as- sume erect position ; pile lacking on most of pleurae, sparse on anepistemum and upper, lateral portions of prosternum, dense in a longitudinal row on pleuro- tergite; pollinose tomentum relatively sparsely covers most of pleural region, lacking on anepimeron. Wing. — Hya- line to infuscate with various, usually : transverse, patterns in browns, yellows, and/or grays ; vein R4 shallowly S curved ; R4 usually longer than R,-,. Legs. — An- terior surface of coxa 1 has 2 apical setae ; posterior surfaces of coxae 1 and 2 shiny, not pilose, and at most very sparsely to- mentose; femora have small, slender, al- most exclusively av or pv setae; setae on feniui 3 from occupying distinctly av and pv positions (mostly North American species) to scattered over ventral sur- face (mostly South American species) ; pile on anterior and dorsal surfaces of femur 3 scalelike, appressed; on ventral surface short, sparse, thin: tibia 1 rela- tively straight, elongate to stout, with dorsal setae lacking or at least shorter tlian width of tibia 1; basitarsus 1 (Fig. 24) swollen, enlarged. Abdomen. — Narrow, nearly parallel sided from segment 1 through 4; there- after abdomen tapers rapidly; segments 6-8 of males telescoped within segment T and ta]jer is cut to blunt point; seg- ments of females not telescoped and ta- per is long and pointed; dorsum of abdomen flattened, more so in males; tergites generally not fasciate, though iiTgite 2 is brown or gray fasciate in a iew species; pile pattern variable, never dense; dorsum of males and, to a lesser degree of females of a few species, densely "iUer. Male Terminalia (Fig. 182-187). — Sternite 8 (Fig. 187) shallowly to deeply bilobate; tergite 8 (Fig. 186) narrowly constricted medially; epandrium (Fig. 183) large, covering most of terminalia, 1.3-1.8X (the higher values occurring in North American species) wider than long (bisected medially longitudinally and latitudinally), with outer posterior margins extended hindward to about level of apex of cerci and ventral epan- drial sclerite, almost always bidentate: cerci (Fig. 183) slightly shorter than ventral epandrial sclerite: cerci joined only basally; ventral epandrial sclerite not keeled, usually incised ; intersegmen- tal membrane basad of this sclerite weakly to heavily sclerotized, strongly attached to sclerite base with 2 arms firmly attached to posterolateral projec- tions of epandrium, and weakly to firmly attached to anterior margin of aedeagus : gonocoxites (Fig. 184) solidly fused along ventral margin, with an elongate, pos- terior projection (Fig. 182) extending beyond apex of gonostylus (South Amer- ican s])ecies) or not (common North American s]3ecies). According to Lyne- borg {1969:407) , sumichrasti (Bellardi) has a broader projection, but clearly this species falls within the concept limits of Cyclotelus. Hypandrium lacking or completely fused with gonocoxites, not identifiable; aedeagus not attached to ventral lobes, but attached to parameral apodeme (Fig. 185) by a heavily sclero- tized rod, which bows anteriorly beyond gonocoxal cavity and sharply hindward and forms a firm connection to the pos- terolateral edge of the aedeagal dorsal apodeme: parameral process (Fig. 185) free, very reduced, knoblike; ventral lobes fused basally, elongate, probably function as a guide for the thin, elongate disti- phallus; length of aedeagus basad of center 1.5-2.OX length distad of center (Fig. 185) ; aedeagal dorsal apodeme and inner dorsal shield each more than twice as wide as base of distiphallus; this cur\ed slightly u[)ward, outward, arching downward and inward, and slightly out- ward at tip: aedeagal ventral apodeme usually narrow (usually less than half as wide as inner shield, but nearly as wide 254 Illinois Natural History Survey Bulletif Vol. 32, Art. 3 in one South American species), elongate (slightly longer than inner dorsal shield) , not forked; inner dorsal shield shallowly bilobate; ejaculatory apodeme large to mediumly small, the distal end expanded, usually horizontally flattened. Habitat E. I. Schlinger (personal communica- tion) has collected specimens in Pervi alighting on sunlit paths in otherwise dense, dank tropical forests. R. H. Painter (Cole 1960a: 168) has collected specimens of rtifiventris (Loew) in "sand dunes" at Medora, Kansas. Three spe- cies, rufiventris, pictipennis, and colei, have been abundantly collected at Sand Ridge State Forest, Mason County, Illi- nois, on oak forested expanses of sand. Distribution Members of the genus Cydotelus have been found throughout the New World tropics of Argentina, Brazil, Paraguay, Uiuguay, Bolivia, and Peru and in southern, eastern, and central Mexico, through the eastern portion of the United States, and westward to the Rocky Moun- tains (e.g., Texas and Montana) and northward into Canada (Manitoba) . Included Species bellus (Cole) 1923a: 32 $, 9 [Epo- niyia bella), new combination. Dis- tribution. — Texas: Macdona, Hi- dalgo County: Laguna Madre, 25 miles southwest of Harlingen : Pa- dilla, Tamaulipas, Mexico. colci Irwin & Lyneborg, new name for scutellaris Loew 1869b, not Walker 1857. Distribution. — Central and eastern United States. scutellaris Loew 1869Z):171 9 (Psilocephala), not Cydotelus Walker 1857:133 (Brazil, Uru- guay, Paraguay) . hardyi'iCole) I960fl:167 {Furdjcra), new combination. Distribution. — Brownsville and Los Borregos, Texas. flavipes Hardy 1943:26 $ (Epo- myia), not Krober 19286:113. pictipennis (Wiedemann) 1821:63 9 (Thereva). new combination. Dis- tribution. — Eastern North America to Michigan and Texas. crythrura Loew 18696:172 3 (Psilocephala) . rufiventris (Loew) 1869a: 126 2 (Psi- locephala), new combination. Dis- tribution.— Ontario. Canada: Rhode Island, Massachusetts. New Jersev. Virginia, Maryland, Florida, AVash- ington, D.C., Ohio, Indiana, Illi- nois, Michigan, Montana, Nebraska. Kansas, Texas, New Mexico, and Arizona. lacteipennis Krober 1914:53 S (Psilocephala ) . Cole 1960a : 168. siitnichrasti (BeWardi) 1861:91 $ (Psi- locephala), new combination. Dis- tribution.—Tuxpango. Orizaba, and Tabasco, Mexico. All of the species from America north of Mexico have probably been described. There are 14 apparently valid species de- scribed from South America. Probably a few species remain undescribed from Mexico and Central America, and un- doubtedly there are several undescribed species from the Amazon Basin north- ward to Panama. Genus Ozodiceroniva Bigot (Fig. 5, 28, 29. and 188-193) Feminine Ozodiccromya Bigot 1889:321. Type-spe- cies: mcxicana Bigot 1889:321 bv ori- ginal monotypy. Type-locality: Mexico. Ozodiceromyia Bigot, error (Bieot 1889: 323). Ozocliccroiiyma. error (W'ulp 1898). Diagnosis Small and slender to large and robust species. He.\d. — Frons of male at its narrow- est narrower than half widUi of anterior ocellus; frons of female at level of an- terior ocellus 1.3-2.3 X as wide as ocellar tubercle: frons of female at le\el of an- tenna 2.8-4.6 X as wide as ocellar tu- bercle: male frons from slightly raised in some species (e.g., californica) to flat- Nov., 1980 Irwin & Lyneborc: The Genera of Nearctic Therevidae 255 tened. narrow in most species, but broad in nanclla and closely related species, tri- angular shaped and with some shiny bare area, usually central ; male frons has some tomentose areas in most species; female frons broad, with shiny bare callus of various sizes and shapes, usually sur- rounded by fine tomentum; frons, face, and genae of both sexes with or without pile; pile usually short and concentrated on upper frons of female ; tomentum on frons, face, and occiput usually silvery; genae usually enlarged, tomentum darker; head greatly (e.g., mexicana) to slightly protiTiding anteriorly at anten- nal level; head depth 0.4-1.4X antennal length (Fig. 28 and 29) ; scape usually slender, 0.5-1.3 X as long as flagellum; first flagellomere variously shaped from elongate to pear shaped, with setae re- stricted to basal third; flagellar style usually apical, from long to short, usually two segmented, with a distinct, terminal spine (although mexicana (Fig. 28) and argentifera have style subapical, and spine of female californica not distinct) ; palps one segmented. Thorax. — np 3-4 (usually 3) , sa 1-2 (usually 2), pa 1, dc 0-2 (usually 0-1), so 1-2 (usually 2) ; mesonotal pile of one 189 193 Fig. 188-193. — Ozodiceromya mexicana Big. male lerminolio. 188. — Genitalia in lateral view. 189. — Right gonocoxite with appendages and aedeagus in dorsal view. 190. — Epandrium with append- ages in dorsal view. 191. — Aedeagus in lateral view. 192. — Sternite 8. 193. — Tergite 8. Scale: 0.5 mm. 256 Illinois Natural History Survey Bulletin Vol. 32. Art. 3 or two types, either simple, erect, rela- tively long or simple, long, erect and scalelike, appressed to semi-appressed, usually bronze to copper colored ; pro- sternum has pile in and around central depression. Wing. — Cell m.-. closed at wing margin; vein R4 slightly longer than vein R5; cell r4 about 2.3 (range 1.6- 2.9) X longer than wide at apex; color hyaline with darkened areas on some spe- cies but not highly mottled; stigma usu- ally dark brown; costal cell darkened in some species. Legs. — Fore coxa has 2 strong, apical setae; fore femur has 0-12 (usually 2-4) setae; hind femur has 4-20 anteroventral plus posteroventral setae (most are anteroventral) ; basitarsus of foreleg often swollen (cf. Fig. 24) . Abdomen. — Moderately slender to broad, gradually tapering from segment 2 to apex; segments 5-8 often telescoped within segments 2-5 of male; abdominal segments not telescoped in female ; dor- sum flattened in both sexes, dorsum of male usually has dense silveiy tomenlum ; both sexes moderately pilose; female ab- domen has grayish silvery tomentum along posterolateral corners of segments. Male Terminalia (Fig. 188-193).— Tergite 8 (Fig. 193) rather large, strongly constricted for most of medial portion; sternite 8 (Fig. 192) ovoid to rectangular, with a deep to shallow notch medially in posterior margin; epandrium (Fig. 190) shorter in midline than wide, ratio of medial length to width 1.7- 4.0; posterolateral corners from greatly flanged (as in some species near nanclla) to squarish, from extending posteriorly beyond cerci to not, from dentate to blunt or smooth, variable; cerci (Fig. 190) free, well separated and moderately to weakly sclerotized; posterior margins of cerci and ventral epandrial sclerites subecjual, cerci longer in some s]5ecies, shorter in others; ventral epandrial scler- ite thinly to moderately sclerotized, with 1 sclerotized island beneath cerci pos- teriorly rounded or notched and 2 elon- gate islands attached to posterolateral margins of epandrium, usually luiiied along midline of epandrium and extend- ing anteriorly usually to or nearly to anterior margin of epandrium, sometimes extending anteriorly beyond epandrium; these anterior sclerites usually thinly, often membranously, attached to an- terior margin of aedeagus ; aedeagus rela- tively large ; distiphallus variously shaped, from thin, tubelike to flattened, from long, sinuate, sometimes recurved be- neath gonocoxites to short; tip of disti- phallus usually thin, sometimes bulbous, swollen, some species (e.g., anomala) having a hooklike projection ventrally at base of distiphallus ; dorsal apodeme from triangular to rectangular and sometimes truncate, the lateral margins often more heavily sclerotized. usually as long as or longer and much wider than ventral apodeme ; ventral apodeme thin, scoop shaped, longer than dorsal apodeme in a few species; ejaculatoiy apodeme usually simple, sticklike, large and club shaped in a few species; center of aedeagus has a variously modified receptacle for proxi- mal end of ejaculatoiy apodeme : ventral lobes well-developed, project dorsally and anteriorly and cradle distiphallus. usually rounded, not connected to aedeagus; parameial apodeme has occasionally a sclerotized and more commonly a mem- branous connection to lateral portion of aedeagus, this connection seems lacking in a few species (as in Fig. 189) ; para- meral process usually vestigial or knob- like, present in the type-species (Fig. 188) as an S-curved sclerotization closely adjoining posterior margin of gonocoxite. not pilose; paraineral a]5odenie heavily sclerotized, situated far from anterior margin of gonocoxite; gonocoxites solidlv united ventromedially over entire length in most species, o\er anterior third in a few; posterior margin of gonocoxites has 1 or 2 (sometimes none) posteriorly di- rected protuberances, either ]X)inted or flangelike; the dorsal portion of these protuberances may represent the parain- eral process, as in mexicana (Fig. 188) : hypandrium absent or completely fused with gonocoxites, not discernible. Habitat Specimens can be encountered in mountainous en\iionmenls and in des- Nov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 257 erts; adults at times can be found on shrubs containing aphid honey dew. Larvae of one species were found in mounds of dirt pushed up by gophers, while larvae of a different species were collected in sandy soils beneath sage- brush. Ozodiceromya is a diverse genus, ! and the habitats occupied by its various species are also diverse. Distribution The genus Ozodiceromya is found throughout the Nearctic Region south- ward into Ecuador and Venezuela in the Neotropical Region. The southwestern ! United States and northwestern Mexico i seem particularly rich in species. Included Species albertensis {Co\&) 1925:86 5, 9 [Psi- locephala) , new combination. Dis- tribution. — Alberta, Canada. aldrichi (Coquillett) 1893&:227 5 (Psilocephala) , new combination. Distribution. — Southern California. anomala (Adams) 1904:444 $, $ {Thereva) , new combination. Dis- tribution. — Arizona, New Mexico, and north-central Mexico. arg^nfabardii Coquillett 1898, HENICOMYIA 262,264 nibcrbis Fallen 1814 (Bibio) PSILOCEPHALA 225 insignata Irwin & Lyneborg, new species, MEGALINGA 242, 244-247 johnsoni (Coquillett) 1893 (Psilocephala) OZODICEROMYA 257 johnsoni Coquillett 1893, THEREVA ...219 lacteipennis (Krober) 1914 (Psilocephala) CYCLOTELUS {see rufiventris (Loew) 1869) 254 laevigata (Loew) 1876 (Psilocephala) OZODICEROMYA {see levigata (Loew) 1876) 257 lateralis (Adams) 1904 (Psilocephala) OZODICEROMYA {see frommeri Irwin & Lyneborg, new name) 257 laticornis Loew 1869 (Psilocephala) BRACHYLINGA {see platycera Loew 1872) 234 latifrons (Cole) 1923 (Psilocephala) DICHOGLENA {see amplifrons (Cole) 1925) 210, 211 levigata (Loew) 1876 (Psilocephala) OZODICEROMYA 257 limata (Coquillett) 1894 (Psilocephala) PANDIVIRILIA 212, 214 LITOLINGA Irwin & Lyneborg, new genus 201, 234-236 longistyla Krober 1914, APSILOCEPHALA 193 lunulata (Zetterstedt) 1838 (Thereva) SPIRIVERPA 214 LYSILINGA Irwin & Lyneborg, new genus 202, 230-232 macdunnoughi Cole 1925, THEREVA ..219 macswaini Irwin 1977, PARAPHEROCERA 264, 266 maculipennis (Krober) 1914 (Psilocephala) RHAGIOFORMA 236, 238 marcida (Coquillett) 1893 (Psilocephala) ARENIGENA 240 MEGALINGA Irwin & Lyneborg, new genus 201, 242-244 melampodia (Loew) 1869 (Psilocephala) DICHOGLENA 212 melanoncura (Loew) 1872 (Thereva) OZODICEROMYA 257 melanophleba (Loew) 1876 (Thereva) TABUDAMIMA 219, 221 melanoprocta Loew 1869, PSILOCEPHALA {see munda Loew 1869) 227 MELANOTHEREVA Malloch 1932 193 metallica (Krober) 1914 (Thereva) OZODICEROMYA 257 METAPHRAGMA Coquillett 1894 {see TABUDA Walker 1852) 221, 223 mexicana Bigot 1889, OZODICEROMYA 254, 255, 256, 257 mexicana Cole 1923, CHROMOLEPIDA 260 millcri (Irwin) 1977 (Breviperna) OZODICEROMYA 249, 258 monensis (Curran) 1926 (Psilocephala) BRACHYLINGA 234 montana Irwin 1977, PARAPHEROCERA 264,266 276 Illinois Natural History Survey Bulletin Vol. 32, Art. 3 montiradicis (James) 1949 (Psilocephala) OZODICEROMYA 258 montivaga (Coquillett) 1893 (Psilocephala) VIRILIRICTA 208, 209, 210 morata (Coquillett) 1893 (Psilocephala) BRACHYLINGA 234 munda Loew 1869, PSILOCEPHALA . . .227 nana (Cole) 1959 (Thereva) OZODICEROMYA [see nanella (Cole) 1960) 258 nanella (Cole) 1960 (Thereva) OZODICEROMYA 255, 256, 258 NEBRITUS Coquillett 1894 . . .201, 249-251 nebulosa Krober 1912, THEREVA 219 neomexicana Cole 1923, THEREVA 219 nervosa (Walker) 1848 (Thereva) TABUDA (see varia (Walker) 1848).. 223 nigra (Bellardi) 1861 (Psilocephala) MELANOTHEREVA 193 nigra (Say) 1823 (Thereva) OZODICEROMYA 258 nigrimana (Krober) 1912 (Psilocephala) OZODICEROMYA 258 nigrimana (Krober) 1914 (subspecies of Thereva bella Krober) SPIRIVERPA. .216 nigrina (Krober) 1914 (Psilocephala) DICHOGLENA 212 nigripes Cole 1923, PHEROCERA 268 nigripilosa Cole 1923, THEREVA 219 nitoris (Coquillett) 1894 (Thereva) SPIRIVERPA 216 nivea Krober 1914 (Thereva) AMMONAIOS {see niveus (Krober) 1914) 240, 242 niveipennis Krober 1914, THEREVA ...219 niveus (Krober) 1914 (Thereva nivea) AMMONAIOS 240, 242 notata (Wiedemann) 1821 (Thereva) OZODICEROMYA 258 novella (Coquillett) 1893 (Thereva) ACROSATHE 225 obliquefasciata (Krober) 1911 (Psilocephala) OZODICEROMYA ...258 obscura (Coquillett) 1893 (Psilocephala) BRACHYLINGA 234 occidentalis (Cole) 1923 (Psilocephala) PALLICEPHALA 208 occipitalis (Adams) 1904 (Psilocephala) LYSILINGA 230, 231, 232 otiosa (Coquillett) 1893 (Thereva) ACROSATHE 225 OZODICEROMYA Bigot 1889 203, 249, 254-258 OZODICEROMYIA Bigot 1889 {see OZODICEROMYA Bigot 1889) 254 OZODICERONYMA, 'Wu\p 1898 {see OZODICEROMYA Bigot 1889) 254 pacifica (Cole) 1923 (Thereva) ACROSATHE 225 PALLICEPHALA Irwin & Lyneborg, new genus 201, 206-208 pallida (Krober) 1914 (Psilocephala) LITOLINGA {see acuta Adams 1903) 236 PANDIVIRILIA Irwin & Lyneborg, new genus 201, 202, 210, 212-214 PARAPHEROCERA Irwin 1977 198, 203, 264-266 pavida (Coquillett) 1893 (Psilocephala) BRACHYLINGA 233, 234 pellucidus Coquillett 1894, NEBRITUS 249, 251 PENNIVERPA Irwin & Lyneborg, new genus 203, 227-229 PHEROCERA Cole 1923. .198, 203, 266-268 PHYCUS Walker 1850 . . .203, 260-262, 263 pictipennis (Wiedemann) 1821 (Thereva) CYCLOTELUS 251, 254 pilosa (Krober) 1914 (Psilocephala) BRACHYLINGA 234 placida (Coquillett) 1894 (Psilocephala) BREVIPERNA 247, 249 plagiata Harris 1835 (Thereva), nomina nuda 270 planiceps (Loew) 1872 (Xestomyza) TABUDA 221, 222, 223 platancala (Loew) 1876 (Psilocephala) OZODICEROMYA 258 platycera Loew 1872 (Psilocephala) BRACHYLINGA 234 plebeja (Linnaeus) 1758 (Musca) THEREVA 216 pollinosa (Cole) 1923 (Psilocephala) PANDIVIRILIA 21 pruinosa (Coquillett) 1904 (Psilocephala) CHROMOLEPIDA 258, 260 pruinosus Walker 1850, CYCLOTELUS. .251 pseudoculata Cole 1923, THEREVA 219 PSILOCEPHALA Zetterstedt 1838 193, 203, 225-227 pygmaea (Cole) 1923 (Thereva) OZODICEROMYA {see nanella (Cole) 1960) 25a pygmaea Krober 1 9 1 1 (Psilocephala) UNPLACED 270 RHAGIOFORMA Irwin & Lyneborg, new genus 201, 236-238 ruficornis (Macquart) 1840 (Thereva) ? OZODICEROMYA 258 rufivcntris (Loew) 1869 (Psilocephala) CYCLOTELUS 254 rugifrons (Krober) 1914 (Psilocephala) OZODICEROMYA 258 SCHLINGERIA Irwin 1977 198, 203, 260, 268-270 schroederi (Krober) 1911 (Psilocephala) OZODICEROMYA 258 scutellaris (Loew) 1869 (Psilocephala) CYCLOTELUS {see colei Irwin & Lyneborg, new name ) 254 semitaria (Coquillett) 1893 (Thereva) ARENIGENA 238, 240 senex (Walker) 1848 (Thereva) SPIRIVERPA 216 senilis (Fabricius) 1805 (Bibio) PENNIVERPA 229 kov., 1980 Irwin & Lyneborg: The Genera of Nearctic Therevidae 277 ericeifrons (Krober) 1928 (Psilocephala) BRACHYLINGA 234 etosa (Krober) 1912, OZODICEROMYA {see mexicana Bigot 1889) 257 etosus Krober 1912 (Euphycus) OZODICEROMYA {see mexicana Bigot 1889) 257 ignatifrons Cole 1923, PHEROCERA " 266, 268 ii;natipennis (Cole) 1923 (Psilocephala) OZODICEROMYA 258 lossonae (Coquillett) 1893 (Psilocephala) ? BRACHYLINGA 234 ilossoni (Coquillett) 1893 (Psilocephala) ? BRACHYLINGA {see slossonae (Coquillett) 1893) 234 ocius Walker 1850, CYCLOTELUS 251 'IPIRIVERPA Irwin & Lyneborg, new genus 202, 210, 214-216 (quamosa (Hardy) 1943 (Psilocephala) BRACHYLINGA 234 trigipes Loew 1869, THEREVA 219 lubnotata (Johnson) 1926 (Psilocephala) OZODICEROMYA 258 lubrufa (Cole) 1923 (Psilocephala) ( LYSILINGA 231, 232 lumichrasti (Bellardi) 1861 (Psilocephala) ; CYCLOTELUS 253, 254 TABUDA Walker 1852 202, 221-223 fABLTDAMIMA Irwin & Lyneborg, new I genus 202, 219-221 fcanneri (Hardy) 1938 (Zionea) I NEBRITUS 249, 251 lepocae (Cole) 1923 (Psilocephala) BRACHYLINGA 234 rr-isa (Say) 1823 (Thereva) LITOLINGA 236 tergissa, hITOhlNGA {see tergisa (Say) 1823) 236 THEREUA {see THEREVA Latreille 1796) 217 THEREVA Latreille 1796 ....202, 216-219 univittata (Bellardi) 1861 (Psilocephala) OZODICEROMYA 258 ustulata Krober 1912, THEREVA 219 utahensis Hardy 1938, THEREVA 219 vanduzeei (Cole) 1923 (Thereva) ACROSATHE 225 varia (Walker) 1848 (Thereva) TABUDA 221,223 variegata (Loew) 1869 (Psilocephala) PALLICEPHALA 206, 207, 208 varipes Krober 1912, HENICOMYIA {see hubbardii Coquillett 1898) 264 vexans (Curran) 1926 (Psilocephala) BRACHYLINGA {see abdominalis (Fabricius) 1805) 234 vialis (Osten Sacken) 1877 (Thereva) ACROSATHE 225 vicina (Walker) 1848 (Thereva) PSILOCEPHALA 227 VIRILIRICTA Irwin & Lyneborg, new genus 202, 208-210 wilcoxi Irwin 1977, PARAPHEROCERA 266 willistoni (Cole) 1965 (Dialineura) PALLICEPHALA 207, 208 xanthobasis (James) 1949 (Thereva) OZODICEROMYA 258 XESTOMYZA 193, 221, 223 ZIONEA Hardy 1938 (see NEBRITUS Coquillett 1894) 249, 251 i Some Publications of the ILLINOIS NATURAL HISTORY SURVEY BLlLLETIN Volume 31. Article 9. — Pesticides and Envi- ronmental Quality in Illinois. By Robert L. Metcalf and James R. Sanborn. August 1975. 56 p., index. Volume 31, Article 10. — The Bantam Sun- fish, Lepomis symmetricus: Systematics and Distribution, and Life History in Wolf Lake, Illinois. By Brooks M. Burr. September 1977. 30 p., index. Volume 32, Article I. — Waterfowl Popula- tions and the Changing Environment of the Illinois River \'allcy. By Frank C. Bcllrose. Fred L. Paveglio, Jr., and Donald W. StefTeck. August 1979. 54 p., index. Volume 32, .\rticle 2. — Primary Insect Types in the Illinois Natural History Survey Col- lection, Exclusive of the Collembola and Thysanoptera. By Donald W. Webb. July 1980. 138 p., index. BIOLOGICAL NOTES 104. — A Summary of the Life History and Distribution of the Spring Cavefish, Cholo- gaster agassizi Putnam, with Population Estimates for the Species in Southern Illi- nois. By Philip W. Smith and Norbert M. Welch. May 1978. 8 p. 105. — Distribution and Abundance of the Gray Squirrel in Illinois. By Charles M. Nixon, Stephen P. Havera, and Robert E. Greenberg. June 1978. 55 p. 106. — The Life History of the Cypress Darter, Etheostoma proeliare. in Max Creek, Illi- nois. By Brooks M. Burr and Lawrence M. Page. July 1978. 15 p. 107. — Soybean Spiders: Species Composition, Population Densities, and Vertical Distribu- tion. By Charles D. LeSar and John D. Unzicker. July 1978. 14 p. 108. — The Nest Biology of the Bees Andrena (Melandrena) regularis Malloch and An- drena (Melandrena) carlini Cockcrell (Hy- menoptera: Andrenidae). By Martha Nor- tham Schrader and Wallace E. LaBerge. August 1978. 24 p. 109.— Illinois Birds: Ciconiiformes. By Jean W. Graber, Richard R. Graber, and Ethelyn L. Kirk. .August 1978. 80 p. 110. — Illinois Birds: Sylviidae. By Jean W. Graber, Richard R. Graber, and Ethelyn L. Kirk. July 1979. 22 p. 111. — Monitoring the Seasonal .\ppearance and Density of the Black Cutworm with a Virgin Female Trap. By Lynn Pautler, William G. Ruesink, Hans E. Hummel, and William H. Luckmann. July 1979. 7 p. 112.— The Life History of the Least Darter, Etheostoma microperca, in the Iroquois River, Illinois. By Brooks M Burr and Lawrence M. Page. August 1979. 16 p. 113. —-The Life Histories of Etheostoma olivaceum and Etheostoma striatulum. Two Species of Darters in Central Tennessee. By Lawrence M. Page. August 1980, 14 p. CIRCULAR 49. — The Dunesland Heritage of Illinois. By Herbert H. Ross. August 1963 (Reprinted May 1974). 28 p. 51. — Illinois Trees: Selection, Planting, and Care, By J. Cedric Carter, March 1977 (Third printing). 123 p. 52.— Fertilizing and Watering Trees. By Dan Neely and E. B. Himelick. December 1971 (Third printing). 20 p. 54. — Corn Rootworm Management in Can- ning Sweet Corn, By W, H, Luckmann, J, T. Shaw, D. E, Kuhlman, R, Randell. and C, D, LcSar, March 1975. 10 p. 55. — Observing, Photographing, and Collect- ing Plants. By Kenneth R. Robertson, August 1980, 62 p. List of available publications mailed on request No charge is made for publications of the Illinois Natural History Sirvev, .\ single copv of most publications will be sent free to anyone requesting it until the supply becomes low. Costly publications, more than one copy of a publication, and publications in short supply arc subjects for special correspondence. Such correspondence should identify the writer and explain the usr to be made of the publication or publications. .'Vddress orders and correspondence to the Chief, Illinois Natural History Survey Natural Resources Building 607 E. Peabody, Champaign, Illinois 61820