Bulletin IL I ILLINOIS ^tura.1 History || I BULLETIN Survey The Mecoptera, or Scorpionflies, of Illinois Id W. Webb lan D. Penny C. Marlin NATURAL HISTORY MHll AUG 2 7 1975 UBRARY >F ILLINOIS ITMENT OF REGISTRATION AND EDUCATION JRAL HISTORY SURVEY DIVISION ^NA, ILLINOIS VOLUME 31, ARTICLE 7 AUGUST, 1975 A ILLII^OIS Na,t\xra.l History Survey The Mecoptera, or Scorpionflies, of Illinois Doiald W. Webb Neman D. Penny Joh C. Marlin STAr. OF ILLINOIS OETVRTMENT OF REGISTRATION AND EDUCATION •^ArURAL HISTORY SURVEY DIVISION ORANA, ILLINOIS I VOLUME 31, ARTICLE 7 ! AUGUST, 1975 STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION BOARD OF NATURAL RESOURCES AND CONSERVATION Ronald E. Stackler, J.D., Chairman; Thomas Park, Ph.D., Biology, L. L. Sloss, Ph.D., Geology, Herbert 8. GuTowsKT, Ph.D., Chemistry, Robert H. Anderson, B.S.C.E., Engineering; W. L. Everitt, E.E., Ph.D., Repre- senting the President of the University of Iltinoin; John C. Guvon, Ph.D., Representing the President of Southern Illinois University. w NATURAL HISTORY SURVEY DIVISION, Urbana. Illinois SCIENTIFIC AND TECHNICAL STAFF George Spruuel, Jr., Ph.D., Chief Alice K. Adams, Secretary to the Chief Kurt T. Clement, B.S., Research Assistant Larry W. Coutant, M.S., Research Assistant Herbert M. Dreier, M.S., Research Assistant Michael A. Frakes, M.S., Research Assistant Thomas K. Hill, M.S., Research Assistant Earl Thomas Joy, Jr., M.S., Research Assistant Richard Kocher, B.S., Research Assistant Robert Moran, M.S., Research Assistant Kathryn Ewing, B.S., Technical Assistant Susan Moore, Technical Assistant Florence Partenheimer, B.A., Technical Assistant C. Russell Rose, Field Assistant Section of Faunistic Surveys and Insect Identification Philip W. Smith, Ph.D., Taxonomist and Head Wallace E. LaBerge, Ph.D., Taxonomist Milton W. Sanderson, Ph.D., Taxonomist Lewis J. Stannard, Jr., Ph.D., Taxonomist Larry M. Page, Ph.D., Assistant Taxonomist John D. Unzicker, Ph.D., Assistant Taxonomist Donald W. Webb, M.S., Assistant Taxonomist Bernice p. Sweeney, Junior Professional Scientist Craig W. Ronto, Technical Assistant Section of Wildlife Research Glen C. Sanderson, Ph.D., Wildlife Specialist and Head Frank C. Bellrobe, B.S., Wildlife Specialist Jean W. Graber, Ph.D., Wildlife Specialist Richard R. Graber, Ph.D., Wildlife Specialist Harold C. Hanson, Ph.D., Wildlife Specialist Ronald F. Labibky, Ph.D., Wildlife Specialist William L. Anderson, M.A., Associate Wildlife Specialist W. W. Cochran, Jr., B.S., Associate Wildlife Speciatiat William R. Edwards, Ph.D., Associate Wildlife Specialist G. Blair Joseltn, M.S., Associate Wildlife Specialist Charles M. Nixon, M.S., Associate Wildlife Specialist Kenneth E. Smith, Ph.D., Associate Chemist Richard E. Warner, M.S., Associate Wildlife Specialist Ronald L. Westemeier. M.S., Associate Wildlife Specialist Stephen P. Havera, M.S., Assistant Wildlife Specialist David R. Vance, M.S., Assistant Wildlife Specialist Ronald E. Duzan, Junior Professional Scientist Helen C. Schultz, M.A., Junior Professional Scientist Eleanors Wilson, Junior Professional Scientist Sharon Fradenburgh, B.A., Laboratory Technician Robert D. Crompton, Field Assistant James W. Seets, Laboratory Assistant Section of Administrative Services Robert 0. Watson, B.S., Administrator and Bead Supporting Services Wilma G. Dillman, Property Control and Trust Accounts Patty L. Duzan, Technical Assistant Robert 0. Ellis, Assistant for Operations Larry D. Gross, Maintenance Supervisor Lloyd E. Huffman, Stockroom Manager J. William Lusk, Mailing and Distribution Services Jerry McNear, Maintenance Supervisor Melvin E. Schwartz, Financial Records James E. Sergent, Greenhouse Superintendent Publications and Public Relations Robert M. Zewadski, M.S., Technical Editor Shirley McClellan, Assistant Technical Editor Lawrence S. Fablow, Technical Photographer Lloyd LeMere, Technical Illustrator Technical Library Doris F. Dodds, M.S.L.S., Technical Librarian Doris L. Sublette, M.S.L.S., Assistant Technical Librarian CONSULTANTS AND RESEARCH AFFILIATES: Systematic Entomology, Roderick R. Irwin, Chicago, Illi- nois; Wildlife Research, Willard D. Klimstra, Ph.D., Professor of Zoology and Director of Cooperative Wild- life Research^ Southern Illinois University; Parasitology, Norman D. Levine, Ph.D., Professor of Veterinary Parasitology, Veterinary Research and Zoology and Director of the Center for Human Ecology, University of Illinois; Entomology, Robert L. Metcalp, Ph.D., Professor of Zoology and of Entomology, University of Illinois; and Gilbert P. Waldbader, Ph.D., Professor of Entomology, University of Illinois; Statistics, Horace W. NOBTON, Ph.D., Professor of Statistical Design and Analysis, University of Illinois. Section of Economic Entomology William H. Luckmann, Ph.D., Entomologist and Head Willis N. Bruce, Ph.D., Entomologist Wayne L. Howe, Ph.D., Entomologist Stevenson Moore, III, Ph.D., Entomologist, Extension Ja&ies E. Appleby, Ph.D., Associate Entomologist Edward J. Armbrust, Ph.D., Associate Entomologist Marcos Kogan, Ph.D., Associate Entomologist Joseph V. Maddox, Ph.D., Associate Entomologist Ronald H. Meyer, Ph.D., Associate Entomologist Robert D. Pausch, Ph.D., Associate Entomologist Ralph E. Sechriest, Ph.D., Associate Entomologist John K. Bouseman, M.S., Assistant Entomologist George L. Godfrey, Ph.D., .4ssistant Entomologist Michael E. Irwin, Ph.D., Assistant Entomologist Donald E. Kuhlman, Ph.D., Assistant Professor, Extension Roscoe Randell, Ph.D., Assistant Professor, Extension William G. Ruesine. Ph.D., Assistant Entomologist James R. Sanborn, Ph.D., Assistant Entomologist Douglas K. Sell, Ph.D., Assistant Entomologist C. Robert Taylor, Ph.D., Assistant Entomologist John L. Wedberu, Ph.D., Assistant Entomologist Clarence E. White, B.S., Assistant Entomologist Tim Cooley, M.A., Assistant Specialist, Extension Kurt E. Redborg, M.S., Assistant Specialist John F. Walt, M.S., Assistant Specialist, Extension Jean G. Wilson, B.A., Supervisory Assistant Stephen Roberts, B.S., Junior Professional Scientist John T. Shaw, B.S., Junior Professional Scientist Daniel P. Bartell, Ph.D., Research Associate Bettina Francis, Ph.D., Research Associate Margaret Anderson, B.S., Research Assistant Robert J. Barney, B.S., Research Assistant Tzu-Sfan Chu, M.S., Research Assistant Stephen D. Cowan, B.S., Research Assistant Stephen K. Evrard, B.S., Research Assistant Marion Farris, M.S., Research Assistant Bonnie Irwin, M.S., Research Assistant Jenny Kogan, M.S., Research Assistant Glenn Levinson, B.S., Research Assistant Rose Ann Meccoli, B.S., Research Assistant Brian Melin, B.S., Research Assistant Celia Shih, M.S., Research Assistant Kathy Wood, M.S., Research Assistant Jo Ann Auble, Technical Assistant Lowell Davis, Technical Assistant Charles G. Helm, M.S., Technical Assistant Linda Isenhower, Technical Assistant Lu-PiNG Lee, M.S., Technical Assistant Section of Botany and Plant Pathology Claus Grunwald, Ph.D., Plant Physiologist and Head Robert A. Evkrs, Ph.D., Botanist Eugene B. Himelick, Ph.D., Plant Pathologist R. Dan Neely, Ph.D., Plant Pathologist D. F. Schoeneweiss, Ph.D., Plant Pathologist J. Leland Crane, Ph.D., Associate Mycologist Walter Hartstirn, Ph.D., Assistant Plant Pathologist Betty S. Nelson, Junior Professional Scientist Gene E. Reid, Technical Assistant Section of Aquatic Biology D. Homer Buck, Ph.D., Aquatic Biologist William F. Childers, Ph.D., Aquatic Biologist R. Weldon Larimore, Ph.D., Aquatic Biologist Robert C. Hiltibran, Ph.D., Biochemist Allison Brigham, Ph.D., Assistant Aquatic Biologist Warren U. Brigham, Ph.D., Assistant Aquatic Biologist Richard E. Sparks, Ph.D., Assistant Aquatic Biologist Ted W. Storck, Ph.D., Assistant .iquatic Biologist John Tranquilli, Ph.D., Assistant Aquatic Biologist Mary Frances Bial, Junior Professional Scientist Carl M. Thompson, Junior Professional Scientist Richard J. Badb, M.S., Research Associate Donald W. Dupford, M.S., Research Associate John M. McNurney, M.S., Research Associate Harry W. Bergmann, B.S., Research Assistant CONTENTS Acknowledgments 252 Natural History 252 Feeding 252 Mating and Oviposition 253 Immature Stages 254 Habitat 257 Distribution and Dispersal 260 Collecting and Preserving Mecoptera 265 Morphology 266 Monographs on Nearctic Mecoptera 268 Taxonomic Treatment 268 Order Mecoptera 268 Family Bittacidae 269 Family Boreidae 277 Family Meropeidae 280 Family Panorpodidae 281 Family Panorpidae 282 Literature Cited 311 Index 315 This report is printed by authority of the State of Illinois, IRS Ch. J27. Par. 58.12. It is a contribution from the Section of Faunistic Surveys and Insect Identification of the Illinois Natural History Survey. Donald W. Webb is an Assistant Taxonomist at the Illinois Natural History Survey. Norman D. Penny and John C. Marlin are former graduate research assistants at the Survey. (66937—3M—8-761 Frontispiece.—A hangingfly, BiKaeus pilicornis, awaiting its prey, which includes mosqui- toes and other bottomland insects. (Photo by W. D. Zehr) rhe Mecoptera, or Scorpionflies, of Illinois Donald W. Webb, Norman D. Penny, and John C. Marlin j THE ORDER MECOPTERA ( scor- pionflies and hangingflies ) is of ancient lineage. Fossils of this order are known from as far back as the Permian. Today relatively few species of Mecoptera bxist; fewer than 500 are currently [•ecorded for the world. They and their fossil relatives exhibit many primi- tive characteristics and are considered among the oldest and most primitive holometabolous insects. Eighteen spe- cies occur in Illinois. They live in mesic places, especially among dense her- fjaceous vegetation in lowland woods. One species of Boreus occurs only on moss in woods and is a relict of the ^ctotertiary forest. This species is found in the southwestern comer of the state. Twenty-one famihes of Mecoptera are recognized, a dozen of which are represented only by fossils. Of the nine extant families, the Bittacidae (hang- jingflies) are the most widespread, oc- jcurring on all continents in tropical and 'warm-temperate regions. The famihes Notiothaumidae (found only in South America) and Meropeidae (one mono- jtypic genus in Australia and one in North America ) are considered the most primitive. Three families, Choristidae, INannochoristidae, and Apteropanorpi- dae, are restricted to the southern hemisphere, occurring in Australia, Tas- mania, or New Zealand. The remaining three families, Boreidae, Panorpodidae, and Panorpidae, are found in North America and Eurasia. The five families (Bittacidae, Borei- dae, Meropeidae, Panorpodidae, and Panorpidae) occurring in North Amer- ica contain 80 species. The majority of these species are distributed through- out the eastern United States. Other species occur in Central America, Mexico, and the western coastal states. With the exception of the family Boreidae, no Mecoptera have been re- corded north of the 50th parallel in North America. The center of distribution of Mecop- tera in the United States is in the southern Appalachians (Byers 1969), from which area the various species have dispersed themselves northward and westward. Thirty-two species are recorded in the Midwest. lUinois, with its extensive north-to-south length and geological history, provides a wide variety of habitats for most groups of Mecoptera. The glaciated regions of northern Illinois, in particular the Northeast Morainal Division', offer suit- able habitat for species, such as Panorpa subfurcata, P. mirabilK, and P. galerita, distributed primarily or wholly in pre- viously glaciated areas. The Coastal Plain Division ( Austroriparian Divi- sion) at the southern tip of Illinois is attractive to those species, such as Panorpa nuptialis, distributed in the coastal plains of the southern Atlantic and Gulf states. The narrow strip of Ozark Division in southwestern Illinois is an extension of the Ozark uplift and provides habitats for species such as Panorpa braueri. Similarly, the Shawnee Hills Division of southern lUinois con- tains habitats similar to those in the southern Appalachians and in Kentucky and Tennessee for such species as Bit- tacus punctiger. The central part of Illinois has areas of deciduous forest along the eastern boundary and prairie and mixed woodland to the west that provide habitats for the other mid- western species. The objective of this study is to up- date our knowledge of the distribution and natural history of Mecoptera, par- ticularly in relation to the biogeographic • Terms from "The Natural Divisions of Illi- nois," Illinois Nature Preserves Commission, 251 252 Illinois Natural History Survey Bulletin Vol. 31, Art. 7; history of Illinois. Synoptic descrip- tions, keys, and illustrations have been prepared to provide an insight into this primitive and interesting group of in- sects. The emphasis of this study is on the fauna of Illinois, but other species oc- curring in the Midwest have been in- cluded. Collecting data are listed for those Illinois species known from fewer than ten localities. Records for other species are plotted on distribution maps. ACKNOWLEDGMENTS Considerable cooperation and advice have been required for this study, and the authors wish to express their sin- cere appreciation to colleagues who have supported and encouraged this work. We wish to thank L. J. Stannard, Ilhnois Natural History Survey, for his advice and guidance in collecting speci- mens and locating unique habitats in Illinois and H. H. Ross, University of Georgia, for his review of the manu- script. In particular, we wish to thank G. W. Byers, University of Kansas, for his advice on the identification of Mecoptera, comments during the prep- aration of this manuscript, and time spent in meticulously reviewing the final copy. Our sincere appreciation is offered to the following organizations and indi- viduals for the loan of material in their collections : American Museum of Natu- ral History, W. Brigham Collection ( Mahomet, Illinois ) , Canadian National Collection, Cornell University, Eastern Illinois University, Field Museum of Natural History, G. Finni Collection (West Lafayette, Indiana), Harvard University, Illinois State Museum, Illi- nois State University, Iowa State Uni- versity, H. R. Lawson Collection (West Lafayette, Indiana), Michigan State University, Naturhistoriska Riksmu- seum (Stockholm), Northern Illinois University, Ohio State University, Pur- due University, Southern Illinois Uni- versity, United States National Mu- seum, University of Arkansas, Uni- versity of California (Davis), Univer- sity of Illinois, University of Indiana,i University of Kansas, University of Ken-i tucky. University of Michigan, Uni- versity of Minnesota, University of Mis-. souri. University of Wisconsin, Western: Illinois University, and Winona Statei College. NATURAL HISTORY Feeding In the Bittacidae, adults of Bittacuss and Apterobittacus are predaceous.i Hanging by their fore or, occasionally, middle legs from the underside of vege- tation, they wait with outstretched hind: legs for some unsuspecting prey. Whenr prey is within reach, it is seized by the ( raptorial tarsi of the hind legs. Thei prey is brought to the mouth, and thei piercing mouthparts enter through thei intersegmental membranes. The softi body parts of the victim are withdrawn, i and the empty exoskeleton is discarded. I Bittacus feed on a wide variety of in- sects. In Illinois Bittacus apicalis, B, strigosus, and B. pilicornis feed heavily) on dolichopodids (Diptera). Setty) (1931 and 1940) and Newkirk (1957) ' listed a wide range of insects that Bittacus accept, noting a preference for Diptera and Homoptera. The time required for feeding varies ! considerably. Setty ( 1931 ) reported : the average time as 20 minutes although ' feeding sometimes lasted as long as ' 40 or 50 minutes. Newkirk (1957) re- ported that the feeding of Bittacus i apicalis may last an hour. He gave a a detailed account of B. apicalis feeding; on aphids: The hangingfly regurgitates a dark- brown fluid, which resembles the i "tobacco juice" of a grasshopper, and covers a part of the aphid with ' it. Through this the hangingfly bites, and sucks out the aphid body fluid. Then the hangingfly injects « saliva, kneads what is left in the ( aphid body cavity with its man- dibles, draws off the mixture; re- Aug., 1975 Webb Et Al.: Mecoptera of Illinois 253 peats this several times; and dis- cards the empty exoskeleton. Very young larvae of bittacids are I relatively active, but older larvae move ' very little (Setty 1940) and can be found among ferns and moist leaf litter in humid lowland woods. They feed on dead or dying animal matter, and it is not known if they can catch live prey. Little is known of the feeding habits of Boreus. Withycombe (1922) ob- served the larvae and Fraser (1943) the adults of Boreus hijemalis feeding on moss. Other substances may also be consumed. In Illinois, Boreus hves in Atrichum angustatum and probably feeds on it. Nothing is known of the feeding habits of the family Meropeidae. The feeding habits of the Panorpidae, in particular Panorpa, have been vari- ously reported in the Hterature. Lyonnet ( 1742 ) initiated the misconception that Panorpa are predaceous when he saw a fly the size of a scorpionfly attack a damselfly and bring it to the ground. Kirby & Spence ( 1823 ) repeated Lyon- net's description and asserted that the species involved was Panorpa com- munis. Since then, numerous authors ( Brauer 1863; Byers 1963; Campion & Campion 1912; Felt 1895; Lucas 1910; Miyake 1912; Shiperovitsh 1925; and Syms 1934) have published observa- tions on panorpids' feeding, and none has been found to be predaceous. Panorpids feed primarily on dead or dy- ing insects although Carpenter ( 1931fo ) reported their feeding on the nectar of flowers, and Miyake (1912) saw them feeding on the petals of sweet william. Larvae of Panorpa feed principally on dead or dying animal matter, but Felt ( 1895 ) reported larger larvae of Panorpa attacking and devouring smaller ones. Mating and Oviposition Setty (1940) and Newkirk (1957) gave detailed descriptions of the mating of Bittacus. The description here is a compilation of both. The male seizes a prey and flies from leaf to leaf in search of a female. When at rest, he vibrates his hind wings, opens and closes his claspers, and bends his abdo- men vertically, everting and inverting his abdominal sacs. Both male and female hang by their fore legs facing each other, and the male offers the prey to the female, which she eats during mating. In some instances the female jabs with her mouth at the male ab- dominal tip, where the eversible sacs are located, or at the prey. The male secures her abdomen in his claspers, then moves along the ventral surface to the terminalia. Only the female feeds during copulation. The length of cop- ulation is proportional to the palatabil- ity of the prey and lasts from 1 to 25 minutes. When copulation is completed, the abdominal tips separate, and the individuals jerk at each other to dis- entangle the legs. Both male and fe- male may mate more than once. During oviposition the female rests on the ground with her head bent down and legs sprawled outwards. The body is quite rigid and the tip of the ab- domen is inserted into cracks in the soil. Oviposition takes from 5 to 30 minutes, and several eggs are laid at a time. The female may fly from place to place and lay a few eggs in each. Oviposition occurs during the day or night. In captivity females tend to lay eggs randomly on the soil surface rather than in some place of concealment. In the Boreidae the mating behav- ior of the European species Boreus hyemalis has been reported by several authors (Brauer 1855; Lestage 1920; Steiner 1937; Stitz 1908; Syms 1934; and Withycombe 1922). Cockle ( 1908) described the mating of B. californicus. Carpenter (1936), Crampton (1940), and Cooper ( 1940 ) described the mat- ing of B. brunudis. The description given here is based on the observations of Cooper (1940) on B. brumalis. The male approaches to within 10 mm or so of the female, and both re- main momentarily stationary. The male may show his excitement by slowly 254 Illinois Natural History Survey Bulletin Vol. 31, Art. 7 waving his antennae or twitching his claspers and wings. He springs at the female with his claspers in advance, seizing the antenna, tibia, or tarsi of the female. The female becomes im- mediately passive, and the male seizes her about the body with his modified wings. Once the female is securely gripped with his wings, the male em- ploys his hind legs and claspers to right the female and move her venter across his back until his terminalia clasp her apical abdominal segments. The eighth sternum of the female is pried down by the male's claspers, which are in- serted into a pair of pockets on the male's ninth tergum. The male releases his wings from the female, and she then flexes her rostrum between her coxae, folds her antennae between her legs, and stretches her legs posteroventrally. Once the female is in this position, the male grips her profemora and rostrum with his clasping wings. This position is maintained throughout copulation of 1-12 hours. The male may run about and feed during copulation, while the female remains motionless. This pat- tern of behavior follows closely ob- servations made on B. californicus and B. hijenialis. According to Carpenter ( 1931Zj ) , Boreus lays eggs one or two at a time at the bases of moss clumps. Nothing has been reported on the mating be- havior or oviposition of the Meropeidae. In Panorpa mating is relatively simple (Miyake 1912). The male vibrates his wings as he approaches the female. The apex of the abdomen is extended with the claspers securing the abdomen of the female. The claspers are moved along the abdomen until the terminalia are reached and the individuals are at an acute angle to each other. In addi- tion, Mickoleit (1971i>) noted the use by P. communis of the notal and post- notal organs as pincerlike devices for holding the costa of the female during copulation. Copulation lasts for 15 min- utes to several hours. Although the mating behavior of Panorpa is simple, there is one peculiarity that has led to some controversy. Mercier ( 1915 ) noted that prior to copulation in P. germanica, P. alpina, and P. cognata the male was seen to emit from its mouth a drop of fluid that hardened into an opaline pellet, which it placed on the soil. The female then fed on the pellet during copulation. When the pellet was consumed, another was produced. Shiperovitsh ( 1925 ) observed males of P. communis emitting cylindrical pellets from their mouths, and Gassner ( 1963 ) noted that unfed specimens of P. nup- tialis regurgitated a brovtoiish secretion on which the female fed during coitus. Syms ( 1934 ) observed no pellets being released but noted that the female fed on a dead insect during mating. Car- penter (1931b) observed the mating of several species of Panorpa but never saw such feeding behavior. One of us (Penny) has observed the depositing of salivary pillars by P. speciosa, P. nuptialis, P. anonmla, and P. Helena. Byers ( 1963 ) observed no salivary se- cretion being produced by the male of P. nuptialis although Gassner ( 1963 ) did observe this phenomenon. In ob- serving the mating of P. sigmoides, Webb saw no evidence of a salivary se- cretion or pellet being offered by the male, nor did the female feed during copulation. In the field P. sigmoides was also observed to mate during the hours of daylight. Most authors have observed mating during the hours of darkness, but Byers (1963) found P. nuptialis to mate only during the day- light hours. During oviposition the female probes the surface of the soil for an appropriate crevice, and the abdomen is extended and inserted deeply into the soil. The number of eggs laid at one time varies. Immature Stages In Bittacus the size and shape of the eggs vary considerably among the spe- cies. The eggs range in length from 0.56 to 0.72 mm and in width from 0.41 to 0.65 mm (Setty 1940). Aug., 1975 Webb Et Al.: Mecoptera of Illinois 255 In B. apicalis the eggs are oval ( Fig. 1) or spherical and have a finely re- ticulated surface. In B. punctiger, B. ; strigosus, B. occidentis, B. stigmatems, and B. pilicomis, the egg shape varies I from cuboidal to heptahedral, and the I egg has a shallow depression on each ' side (Fig. 2). The surface is rough and has numerous small protuberances. Prior to hatching, the eggs become spherical and increase in size (Setty 1940). B. punctiger and B. pilicomis eggs hatch within 2 weeks, and the im- matures overwinter as larvae. B. strigo- sus, B. apicalis, and B. stigmaierus pass the winter in the egg stage. The newly hatched larva emerges through an irregular crack in the wall of the egg and feeds on the remnants of the egg shell. The larvae do not burrow through the soil in search of food, but the older larvae lie motion- less on the surface among the leaf litter and ground debris. The larvae pass through five instars before pupating (Setty 1940). The larvae of Bittacus (Fig. 3) are cylindrical and range in length from 11 to 14 mm in the last instar. The heavily sclerotized head is broad an- teriorly. In lateral view the head is oval or elliptical. It is generally bent under the body so as to be completely hidden from above by the thorax. The antennae are short and stout and have only two segments. The single median ocellus is present as well as two large lateral eyes, which are not true com- pound eyes, according to Setty (1931 and 1940), but simply a group of sev- eral ocelli. The mandibles are large and heavily sclerotized and bear several Fig. 1-2.—Bittacus eggs. 1. — B. apicalis. 2.—B, strigosus. Fig. 3.—Bittacus strigosus larva. large teeth. The labial and maxillary palps are short and stout and have two and four segments, respectively. The head bears numerous coarse setae and tubercles. Each of the three thoracic segments bears a pair of sharply pointed legs, and each of the first nine abdomi- nal segments possesses a pair of short ventral prolegs. The last abdominal segment bears a ventral protrusible sucker that aids in locomotion. The dorsal and lateral margins of the thorax and abdomen bear several simple or branched protuberances, each with a simple or clavate apical seta. Indi- viduals collected in the field usually are covered with soil which clings to these setae and protuberances. The larvae are negatively phototropic and prefer moist shaded areas. Prior to pupation the fourth instar larva bur- rows into the soil, forming a diagonal cylindrical chamber (Setty 1940). The larva constructs a collar around the opening with a thin layer of soil laid across it. At this time the larva molts to form a prepupa. The prepupa re- mains in the bottom of the chamber, for 9-18 days in the case of B. punctiger (Setty 1940), following which it meta- morphoses into a pupa. In the case of B. punctiger, the pupa remains in the chamber for 13 20 days (Setty 1940), after which the adult emerges through the opening that the larva had entered. Setty (1931, 1939, 1940, and 1941) has done extensive work on the mor- phology and behavior of the North American species of Bittacus, and much of the description of the immature stages presented here was extracted from his publications. 256 Illinois Natural History Survey Bulletin Vol. 31, Art. 7 In North America the complete life history of Boreus has not been pub- lished for any species. The description presented here is for B. hyeinalis, as described by Withycombe (1922 and 1926). The eggs of Boreus are about 0.5 mm long and 0.3 mm wide. They are laid at the base of moss, and the larvae hatch in about 10 days, usually in late fall. The larvae pass through four in- stars, a mature larva (Fig. 4) being 6-7 mm long. The head is pale yellow and heavily sclerotized. The eyes are small and composed of several small facets. Mandibles are large, dark brown, and heavily sclerotized. Antennae are small and have two segments and a fine apical bristle. Labial palps are small. The thorax is pale white and broad and has three pairs of ventro- laterally extended legs. The legs have three segments, the basal segment be- ing broad and the others tapering to a small, acute apical segment. The abdomen is pale white and without lateral appendages and has the apex rounded. Each segment has several fine setae. The larvae appear to aestivate throughout the summer in small cells made in compacted soil in which they pupate in late fall. The duration of the pupal stage is 4-8 weeks. Nothing is known of the immature stages of the Meropeidae. In Panorpa the size and characteris- tics of the egg vary considerably. In the lugubris group the eggs of P. nup- tialis are spherical or oval with a smooth surface and measure about 1.07 mm in length and 0.84 mm in width when laid (Byers 1963). In the rujes- cens group the eggs of P. helena are oval, have a fine network of depressions covering the surface, and measure about 1.10 mm in length and 0.65 mm in width. Felt (1895) described the eggs of P. debilis ( as P. rufescens ) as ellipti- cal and oval, 0.625 mm long, and 0.6 mm wide. Numerous authors (Brauer 1852; Byers 1963; Felt 1895; Syms 1934; and Yie 1951 ) have observed that the color of the egg darkens before hatching. The duration of the egg pe- riod is about 8 days for P. nuptialis (Byers 1963) and 6-7 days for P. debilis (Felt 1895). Gassner (1963) observed an egg burster on the frons of the first instar of P. nuptialis. It is used in rupturing the chorion of the egg. According to Gassner, the larva assumes a flattened spiral position prior to hatching. It expands and forces the egg burster through the chorion. The larva then makes a quarter turn and slices open the shell. The larva of Panorpa (Fig. 5) is elongate and cylindrical. It passes through four larval instars before pupa- tion (Boese 1973; Byers 1963; Mampe & Neunzig 1965; Shiperovitsh 1925; Yie 1951). Based on measurements of head width, Felt (1895) reported P. debilis (as P. rufescens) as having seven larval instars, as Miyake (1912) reported for P. klugi. Carpenter ( 1931a ) also described Panorpa as having seven instars. The antennae are short and stout and have a scape, a pedicel, and one flagellar segment. The eyes are composed of 25 or more facets. The mandibles are large and heavily sclero- tized and have two to four mesal teeth. The thorax bears a pair of short Fig. 4.—Boieut brumalis larva. Fig. 5.—Panorpa sp. larva. Aug., 1975 Webb Et Al.: Mecopteba of Illinois 257 pointed legs on each segment and a thick sclerotized pronotal shield. A single pair of spiracles is present on the pronotal segment. The thorax and the abdomen bear numerous setigerous prominences (pinacula) and unmodi- fied setae. The eighth and ninth ab- dominal segments each possess a pair of annulated setae borne on moderately sclerotized projections and a single an- nulated seta on segment 10. A pair of prolegs and a lateral spiracle are pres- ent on abdominal segments 1-8. Four translucent, retractible anal lobes and a basal fold of skin comprise the Uth segment. Byers (1963) reported in detail on the life history of P. nuptialis, from which much of the information pre- sented here has been taken. Boese (1973), Felt (1895), and Mampe & Neunzig (1965) have described other North American larvae. Several authors have described the immature stages of European and Asian panorpids ( Brauer 1863; Miyake 1912; Shiperovitsh 1925; Steiner 1937; and Yie 1951). After hatching, the larvae burrow far- ther into the soil and feed primarily on decaying organic matter although Felt ( 1895 ) reported some larvae as being predaceous. The larvae spend 4—5 days in each of the first three instars and are active and feed for about 2 weeks in the fourth instar, following which the full- sized larvae become quiescent and con- struct prepupal cells. The prepupal cell is oblong with rounded ends and is formed in compacted soil. The cell is about as long as the larva but possesses no visible hd, hke that noted by Yie ( 1951 ) in Formosan panorpids. The larvae then enter a prepupal or qui- escent stage, which carries them through the winter. The duration of the pupal stage varies from 6 to 21 days. Prior to emergence the pupal skin splits along the dorsal midline, and the adult emerges. The hour of emergence is dependent upon the species. Yie (1951) found that in Formosan panorpids emergence oc- curred most often in the early morning. Habitat In the Bittacidae most species are restricted to the humid, well-shaded Fig 6—Herbaceous vegetation in lowlands along the Illinois River, Starved Rock State Park, Illinois. (Photo by H. H. Ross, courtesy of Section of Botany and Plant Pathology, Illi- nois Natural History Survey) 258 Illinois Natural History Sxirvey Bulletin Vol. 31, Art. 7 Fig. 7.—Deciduous forest and herbaceous vegetation along creek bed at Trestle Hollow, Fountain Bluff, Jackson County, Illinois. (Photo by W. D. Zehr, courtesy of Section of Botany and Plant Pathology, Illinois Natural History Survey) Fig. 8. — Bittaeus apiealis hanging from herbaceous vegetation. (Photo by W. D. Zehr) ^ug., 1975 Webb Et Al. : Mecoptera of Illinois 259 ireas along streams and in bottomlands and 9 ) can be found hanging from the Fig. 6 and 7 ) . Individuals ( Fig. 8 undersides of leaves of jewelweed ( 7»7i- Fig. 9.—Bittaeut pilieornis hanging from herbaceous vegetation. (Photo by W. D. Zehr) 260 Illinois Natural History Sltrvey Bulletin Vol. 31, Art. 7 patiem sp. ) , stinging wood nettle ( La- portea canadensis), gooseberry (Ribes sp. ), and a variety of other bottomland plants. Bittacus strigosus has the widest range of habitats, extending from the moist bottomland areas to the drier hill- side areas and occurring predominantly on multiflora rose (Rosa multifJora) . In western Illinois B. strigosus was col- lected abundantly in short pasture grass in the shade of poplars (Populus sp. ). Little is known of the habitat for B. occidentis. Most of the individuals collected have been taken at lights. In the Boreidae the various species are highly restricted in habitat. Speci- mens are collected only in, or very close to, patches of moss on the ground (Fig. 10). In southern Illinois B. brumalis lives in Atrichum angustatum and Dicranella heteromalla. Of the habitat of the Meropeidae little is known. The majority of speci- mens have been collected in a variety of hardwood forests but mostly at lights or in Malaise traps. Occasionally indi- viduals have been found under stones or rotting logs. The habitats of the Panorpidae are similar to those of Bittacus. Individuals of Panorpa (Fig. 11) are most com- monly collected as they rest on the leaves of stinging wood nettle, poison ivy (Rhus radicans ),watei\en{ (Hydro- phyUitm appendiculatum) , jewelweed, and a variety of other broad-leaved plants. Only members of the lugubris group shun the shaded humid areas along streams and are found in the short grasses along roadside ditches or in cotton, tobacco, and soybean fields. DISTRIBUTION AND DISPERSAL The order Mecoptera is one of the most generalized groups of holometab- olous insects and has an abundant fossil record dating back to the early Permian (Tillyard 1935). The Bittacidae are the most highly specialized family of the Mecoptera. Fig. 10.- Stannard) -Patches of moss on a hillside in Lake Murphysboro State Park. (Photo by L. J. Aug., 1975 Webb Et Al.: Mecoptera of Illinois 261 Fig. 1 1 .—Panorpa sp. on herbaceous vegetation. (Photo by W. D. Zehr) Their tipulidlike appearance, single raptorial claw on the tarsus, and pre- daceous habit are three of the most sig- nificant specializations. Although bit- tacids have the bulbous basistyles of most of the Mecoptera, the presence of a four-branched sector vein and the absence of a notal organ suggest that this family's specialization began at an early date. Jurassic fossils of Probit- tacus and Protobittacus (Tillyard 1935) also suggest early specialization. In the Nearctic Region the Bittacidae are represented by two genera, Bittacus and a wingless form, Apterobittacus. Apterobittacus is monotypic and found only in central California (Fig. 12) except for one doubtful record from southwestern Colorado. Bittacus, the most widespread genus of the Mecop- 262 Illinois Natural History Survey Bulletin Vol. 31, Art. 7 Fig. 12.—General distribution of Bittacus (dots) and Apl«robittaeus (lines) in the Nearc- tic Region. tera (Fig. 12), extends from northern Florida to Quebec, west to eastern Montana, then south to Mexico, and an isolated species (B. chlorostigma) is restricted to California and Oregon. The spread of the Bittacidae into the Nearctic Region (Byers 1969) possibly occurred during the late Mesozoic or early Tertiary, following the emergence of the Bittacidae prototype on the former southern land mass, Gondwana- land. All bittacid genera, except Bit- tacus and two apparently recent flight- less derivatives of Bittacus, are re- stricted to Australia and South and Central America. After the establishment of land con- nections between North and South America, Bittacus dispersed northward and is known from North American Eocene fossils ( Carpenter 1955 ) . Glaci- ations during the late Pliocene or early Pleistocene then forced the bittacids into the southern United States, Mexico, and South America ( Byers 1969 ) . After the glaciations the bittacids in the southeastern United States became sep- arated from the main bittacid stock in Central America by xeric conditions and the disappearance of mesic forests from northern Mexico and the South- west. Following the retreat of the gla- ciers, the southeastern bittacids spread northward and westward, and a second invasion from Mexico brought B. chlo- rostigma to California and B. texanus to the Southwest. Illinois forms the northwest border of the distribution of B. apicalis (Fig. 43) and B. punctiger (Fig. 44). B. stigmaterus, B. pilicornis, and B. strigo- sus occur throughout Illinois and extend into the west-central states. B. occi- dentis has been collected only in central and northern Illinois although it is wdde- spread from southern Ontario and New York southwestward to Arizona. Of the midwestern species, only B. texanus has not been recorded from Illinois. The other three North American fam- ilies (Boreidae, Panorpodidae, and Panorpidae) are all confined to the temperate and boreal forests of the northern hemisphere. All have bulbous Aug., 1975 Webb Et Al.: Mecoptera of Illinois 263 Fig. 13.—General distribution of the Boreidae in the Nearctic Region. basistyles and pincerlike dististyles. Each has survived in a slightly different climatic zone. The Boreidae are found primarily in the colder regions of the northern hemisphere from St. Paul Island in the Bering Sea to 12,000 feet in the Colorado Rockies ( Fig. 13 ) . In eastern North America the family has spread northward from the southern Appa- lachians, leaving relict populations in marginal habitats in the southern por- tions of its range. Adaptations to cold environments include reduction in size, loss of flight and reduction in wing size, and loss of the notal (wing-clasp- ing) organ. The family Meropeidae is the most primitive family of the Mecoptera in North America. The broad wings with numerous costal crossveins, the short rostrum, and the elongate male ba- sistyles and dististyles indicate the prim- itive nature of this family. The recent distribution of Merope ( Fig. 14 ) ( Byers 1973b) indicates the center of specia- Fig. 14.—General distribution of the Mero- peidae in the Nearctic Region. tion to be in the southern Appalachians, from which area this genus has dis- persed northward and to the east and west. Although widespread in the north- eastern United States, records of this genus are sparse. In Illinois Merope has been recorded only from Pine Hills Ecological Area and Urbana. 264 Illinois Natural History Survey Bulletin Vol. 31, Art. 7 The family Panorpodidae is found in boreal environments of montane areas of the southern Appalachian and the northwestern states ( Fig. 15 ) . Normally this family is distributed in cool areas from sea level to higher elevations in North America. Adaptations to such boreal environments include the Sight- lessness of females and the loss of the male notal organ. The Panorpidae normally live at lower elevations than do the Boreidae and Panorpodidae, but ranges may broadly overlap. Species of the Panorpi- dae and Panorpodidae from Japan have almost identical wing venation; the North American Panorpodidae {Bra- chypanorpa ) have a reduced number of sector branches. The male genitalia of the Panorpidae and Panorpodidae are also very similar, indicating a close re- lationship between these two families. However, Oligocene Baltic amber has yielded specimens of both Panorpa and Panorpodes so different that these fam- ilies must have diverged before the Oligocene. The majority of Nearctic Panorpidae are distributed in the eastern United States, and several species are recorded from the Southwest and Mexico (Fig. 16). Byers (1969) partitions the genus Panorpa north of Mexico into six dis- tributional groups: 1. Those species occurring only in the southern Appalachians. This group contains five species found only at the middle to higher elevations. 2. Those found in the southern Ap- palachians but also distributed widely to the northeast, northwest, and west. This group contains eight widely dis- tributed species. All extend into the Midwest, and four species occur in Illinois (P. banksi, P. debilis, P. helena, and P. nehulosa). 3. Those occurring primarily in the Piedmont and sometimes up into the valleys of the Appalachians. Species in this group occur principally on the east- ern side of the Appalachians although both P. consuetudinis {= P. elahorata) and P. rufescens extend into the Mid- west. Fig. 1 5.—General distribution of the Panorpodidae in the Nearctic Region. Aug., 1975 Webb Et Al.: Mecoptera of Illinois 265 Fig. 16.—General distribution of the Panorpidae in the Nearctic Region. 4. Those inhabiting the coastal plain from Texas eastward to Florida and northeastward approximately to New Jersey. This group contains seven species, only one of which (P. nup- tialis) extends northward into the Mid- west and is known from within 1 mile of Illinois near Cairo. 5. Those occurring primarily or wholly in the formerly glaciated area of the northern Appalachians and west- ward. The five species in this group all occur in the Midwest to the north and east of Illinois. 6. Those found only in the Midwest. This group contains six species, four of which (P. anomala, P. dubitans, P. speciosa, and P. sigmoides) occur in Illinois. Most species of Panorpa inhabit mesic temperate forests with humid, dense undergrowths of herbaceous veg- etation. During periods of glaciation in North America these species possibly sought areas of relatively stable climatic conditions (Byers 1969), such as those in the southern Appalachian and Ozark- Ouachita uphft. During interglacial periods the species spread northward. The southern Appalachian area has the greatest concentration of Panorpa species in North America. All the species in Byers' groups one through live and some in group six appear to have arisen from a southern Appala- chian ancestral stock and migrated northward and westward. In group six Byers lists six species which occur only in the Midwest. Judging from their present distributions, one can infer that three of them ( P. anomala, P. speciosa, and P. hraiieri) may have differentiated in the area of the Ozark-Ouachita uphft. COLLECTrNG AND PRESERVING MECOPTERA With the exception of the Boreidae, the Mecoptera are generally found on, or hanging from, low herbaceous vege- tation in shaded moist woodlands. Bit- tactis can be found by walking slowly through shaded weedy areas and brush- ing the vegetation back and forth with a net. When disturbed, bittacids will fly 10-20 feet ahead of the collector and 266 Illinois Natural History Survey Bulletin Vol. 31, Art. 7 then hang from the vegetation again. The experienced collector may net spec- imens in flight or follow their flight and collect them as they hang from the vegetation. Some bittacids (B. apicalis and B. occidentis) have been collected at lights. The collecting of Boreus calls for a rather hardy, determined collector, be- cause these insects reach maturity dur- ing late fall and winter. They are asso- ciated with mosses on the ground, on bases of trees, and elsewhere. They can be collected by lying beside a patch of moss and waiting for the adults to move. They also move about on patches of snow, where they are easily seen and collected. Larvae of Boreus have been taken by Berlese funnel extraction from moss. The collecting of Merope has been accomplished more by chance than by skill. Most specimens have been col- lected at lights or in Malaise traps in heavily wooded areas. Panorpa can be collected individually from the surface vegetation. The col- lector must stalk slowly through the vegetation, particularly stinging wood nettle, until an individual is located. When disturbed, the somewhat seden- tary members of this genus will fly a short distance or drop to the ground and escape in the leaf litter. Panorpa is seldom taken at lights. Specimens of Mecoptera can be pre- served in 70-percent ethyl alcohol or mounted on insect pins. The taxonomic characters necessary to separate the genera and many of the species can be seen with a stereoscopic microscope. In the females of Panorpa, the genital plate is of taxonomic impor- tance. To observe this plate, one must cut off the tip of the abdomen basal to the eighth segment and boil the tip in 10-percent KOH or leave it overnight in cold 10-percent KOH to remove the soft internal tissues. The tip is trans- ferred to 70-percent ethyl alcohol, and the abdominal terga and sterna are sep- arated with a pair of dissecting points. revealing the genital plate. In identi- fying males of some species of Panorpa, clearing the genital bulb in 10-percent KOH aids in species determination. MORPHOLOGY Several excellent papers have been published on the external and internal anatomy of the Mecoptera (Crampton 1921 and 1931; Dohanian 1915; Grasse 1951; Hepburn 1969 and 1970; Micko- Fig. 1 7.—Panorpa Helena anterior view of head. Fig, 18-19. — Bittaeus ttrigosus. 18.- Apical tarsal segments with claw. 19.- Apical tarsal segments with claw reflexed. Aug., 1975 ANTENNA — Webb Et Al.: Mecopteba of Illinois FORE WING 267 MAXILLARY PALPS ASISTYLE 20 Fig. 20. — Panorpa sp. lateral view of male adult. leit 1971a; Otanes 1922; and Potter 1938). The descriptions are supplemented with illustrations of the morphological characters of taxonomic importance. Fig. 17 presents an anterior view of the head of Panorpa, showing the dis- tinctive elongate rostrum of most of the Mecoptera. Ocelli are present in all genera of the North American Mecop- tera except Merope. In Boreus the ocelli are indistinct, and numerous au- thors have reported them absent. In all genera the large, lateral compound eyes are widely separated, except those of Merope, which are reniform and al- most contiguous dorsally. The shape and venation of the wings vary from genus to genus. Fig. 24, 50, 64, and 80 illustrate the wings of all midwestern genera. In Apterobittacus the wings are absent, and in certain Fig. 21A-B. — Panorpa sigmoides. A.—Ventral view of male terminalia. DS, dististyle. VP, ventral paramere. BS, basistyle. HY, hypandrium. B.—Dorsal view of male terminalia. DS, dististyle. BS, basistyle. 9T, ninth tergum. 268 Illinois Natural History Survey Bulletin Vol. 31, Art. 7 species of Brachijpanorpa the females have greatly reduced wings. The legs in all genera are elongate and cylindrical. In Panorpa the apical tarsal segment bears a pair of serrate claws. In Bittacus and Apterobittacus the tarsi have a single apical claw ( Fig. 18 and 19), which reflexes back into a groove in the fourth tarsal segment. This claw is used in holding prey. Fig. 20 is a lateral view of a Panorpa male and illustrates the scorpionlike appearance of the genus. The abdomen is thick and rounded basally arid tapers apically to the elongate seventh and eighth segments. The terminalia are bulbous and reflexed over the abdomen. In Panorpa the sixth abdominal tergum in males may or may not possess an anal horn. The terminalia of Panorpa are shown in Fig. 21A and 21B, and the morpho- logical characters of taxonomic impor- tance are identified. MONOGRAPHS ON NEARCTIC MECOPTERA Because of the small number of spe- cies of Nearctic Mecoptera, few major taxonomic revisions have been done on this group. Westwood ( 1846 ) in his monograph on the genus Panorpa de- scribed several Nearctic species. Walker (1853), Hagen (1861), Banks (1907), and Esben-Petersen (1915) catalogued the North American Mecoptera, and Hine (1898 and 1901) reviewed the Mecoptera north of Mexico. In 1908 Sherman reported on the Panorpidae of North Carolina; Engelhardt (1915), the Mecoptera of the northeastern United States; and Esben-Petersen (1921), the North American species. The major revision of the Nearctic Mecoptera was published by Carpenter (1931a) wherein he described many new species. Since then new species have been described and additional dis- tribution data have been reported by Carpenter ( 1932fl, 1935, 1936, and 1939) and Byers (1954, 1958, 1962a, 1962fo, and 1973c). TAXONOMIC TREATMENT Order MECOPTERA MECOPTERA Comstock & Comstock 1895 MECAPTERA Packard 1886 PANORPATAE Brauer 1885 The members of the order Mecoptera are moderately large, holometabolous insects, having biting mouthparts gen- erally extended ventrally to form a pro- longed rostrum. The antennae are elongate and filiform and have about 20 flagellar segments. The large com- pound eyes are dichoptic. Ocelli are present or absent. The maxillary palps have five segments. The thorax is broad dorsally and tapered ventrally. The wings are usu- ally elongate and narrow. The fore and hind wings are nearly equal in length and have numerous veins and crossveins. In several genera the wings are greatly reduced or absent. In Merope and NotiothauTna the wings are very broad and rounded apically. The legs are long and slender and have five tarsal segments, ending in one or two claws. The coxae are large, and each tibia bears a pair of long spurs. The first abdominal segment is fused to the thorax. The abdomen is gener- ally thick basally and tapered apically except in the Bittacidae. Cerci are present apically in females and subapi- cally in males. KEY TO THE NEARCTIC FAMILIES OF MECOPTERA 1. Tarsi with single apical claw (Fig. 19) Bittacidae Tarsi with two apical claws 2 2. Male brachypterous. Female with ovipositor Boreidae Male with elongate wings. Female without ovipositor 3 3. Wings broad, rounded apically (Fig. 64), with numerous costal cross- veins. Ocelli absent Meropeidae Wings narrow, elongate (Fig. 73), with few costal crossveins. Ocelli present * 4. Rostrum short Panorpodidae Rostrum long (Fig. 17) Panorpidae Aug., 1975 Webb Et Al.: Mecoptera of Illinois 269 BITTACIDAE Enderlein 1910 The raptorial tarsi with a single claw separate the bittacids from other fami- lies of the Mecoptera. Twelve genera are distinguished, and their species are recorded from all continents although they are generally absent from the northern parts of Europe, Asia, and North America. Bittacus is the most widespread genus, occurring in Europe, Asia, Africa, and North and South America. Apterobittacus, found in Cali- fornia, and Anomalohittacus from South Africa are the only flightless genera. Anabittacus, Nannobittacus, Neobitta- cus, Pazitis, and Issikiella occur in South and Central America. Kalobit- tacus is recorded from Central America. Austrobittacus, Edriobittacus, and Har- pobittacus occur only in Australia. Of the two Nearctic genera, only Bittacus has been collected in Illinois. KEY TO THE NEARCTIC GENERA OF BITTACIDAE 1. Wings present Bittacus Wings absent Apterobittacus Apterobittacus MacLachlan Apterobittacus MacLachlan ( 1893: 317). Type-species by monotypy. Apterobittacus apterus MacLachlan. Body dark brown, length 20-23 mm, tipuliform. Antennae filiform with 13 flagellar segments. Both sexes wing- less. Legs similar to those of Bittacus. Abdomen thick, cylindrical. In males, lobes of ninth abdominal tergum in lateral view, broad, subrectangular, ex- tending well beyond apices of basi- styles; in dorsal view, narrow, com- pressed laterally, apices converge. Ba- sistyles broad, thick, fused ventrally. Dististyles small. Aedeagus thick ba- sally, tapering apically to short, looped thread. This is a monotypic genus probably restricted to California. Bittacus Latreille Bittacus Latreille (1805:20). Type- species: Bittacus italicus Miiller. Leptobittacus Hine (1898:108). Pro- posed by Hine for the species B. strigosus and B. pilicornis. However, Hine retained them in the genus Bittacus. Thyridates Navks (1908:412). Synony- mized by Banks (1913). DiplostigmaNdvks (1908:413). Synony- mized by Banks (1913). Haplodictyus Navas (1908:413). Syn- onymized by Banks (1913). Head small, pale to dark yellow, ta- pered ventrally to form distinctive ros- trum. Eyes large. Ocelli large, amber, on raised subtriangular pad. Antennae long, filiform with 14 flagellar segments. Thorax broad, compressed laterally. Wings long, narrow, tapered basally. Membranes clear or yellow, often with dark brown apex or crossveins. Sub- costa ending in middle of wing. Sub- costal crossvein (Fig. 24) usually basal to first fork of radial sector. R, forked apically to form pterostigma, which has one or two pterostigmal crossveins. Pterostigma (Fig. 22) darker than sur- rounding membrane. A whitish thyrid- ium (Fig. 26) around first fork of media. Apical crossvein (Fig. 24) pres- ent or absent. Legs elongate, slender, cylindrical. Coxae large, thick, tapered apically. Femora generally slender al- though hind femora often swollen. Tibiae long, slender with two long spurs. Basal four tarsal segments cylin- drical with small apical enlargment; fifth segment fused to apical claw which is reflexed to fit into groove in fourth segment. Abdomen long, narrow basally. Male terminalia large (Fig. 29). Ninth ter- gum modified to form two laterally flat- tened claspers, often extending beyond apices of basistyles. Basistyles broad, fused ventrally, each with short, medi- ally extended dististyle. Aedeagus thick basally, tapering apically. Internal skeleton of female genitalia absent. Sternal region of eighth and ninth seg- ments fused to form subgenital plate. Tenth segment bears pair of unseg- mented cerci. Seven species of Bittacus occur in the Midwest. 270 Illinois Natural History Survey Bulletin Vol. 31. Art. 7 Fig. 22-28.—Bittaeus fore wings. 22.—B. apicalis. Pt, pten 24. — B. pilicornis. AC, apical crossvein. 25. — B. oecidentis. ScC B. strigosus. Th, thyridium. 27.—B. stigmaterus. 28.—B. texani ills. Pt, pterostigma. 23. — B. punctiger. '"'— 'i. ScC, subcostal crossvein. 26. — texanus. KEY TO THE MIDWESTERN SPECIES OF BITTACUS 1. Apices of wings dark brown (Fig. 22) apicalis Apices of wings not dark brown ... 2 2. Apical crossvein present (Fig. 24) . . 3 Apical crossvein absent (Fig. 25) . . . 4 3. Hind femora with brown spot sur- rounding base of setae . . . .punctiger Hind femora without brown spot sur- rounding base of setae pilicornis 4. Subcostal crossvein distal to first fork of radial sector (Fig. 25) .... oecidentis Subcostal crossvein basal to first fork of radial sector (Fig. 26) 5 5. Wing membranes colorless. Cross- veins margined (Fig. 26) . . . .strigosus Wing membranes yellow to pale brown. Crossveins usually not mar- gined (Fig. 27) 6 6. In males, lobe of ninth tergum in dorsal view with two medial prom- inences, each prominence bearing several black spines (Fig. 40). In females, wing color yellow to amber stigmaterus In males, lobes of ninth tergum in dorsal view with one medial prom- inence bearing several black spines, and each lobe with a row of 10-15 thick black spines basal to medial prominence (Fig. 42). In females, wing color brown to dark brown texanus Aug., 1975 Webb Et Al.: Mecoptera of Illit'ois 271 Fig. 29-42. — Bittaeus male terminalia. 29. — B. apicalis. Lateral view of terminalia. 9t, ninth tergum. Ce, cerci. Bs, basistyle. Ds, dististyle. Ae, aedeagus. 30.—Dorsal view of ninth tergum. 31. — B. punctiger. Dorsal view of ninth tergum. 32.—Lateral view of ter- minalia. 33. — B. pilicornis. Lateral view of terminalia. 34.—Dorsal view of ninth tergum. 35. — B. occldentis. Lateral view of terminalia. 36.—Dorsal view of ninth tergum. 37. — B. sfrigosus. Lateral view of terminalia. 38.—Dorsal view of ninth tergum. 39. — B. stigmaterus. Lateral view of terminalia. 40.—Dorsal view of ninth tergum. 41. — B. texanus. Lateral view of terminalia. 42.—Dorsal view of ninth tergum. 272 Illinois Natural History Suh\t:y Bulletin Vol. 31, Art. 7 Bittacus apicalis Hagen Bittacus apicalis Hagen ( 1861:248).