\ BULLETIN t OF THE ILLINOIS STATE LAB'ORATORY OF NATURAL HISTO RY 1 RBA I , l LLI~OIS . L . ~. \ . ,J.\NUARY, HIt)7 _\ ' H'I' l l r. , \ ' II\ 01 .. \ 11. 0 .' THE llIOLOOi OF TilE RA:\,D AREA~ 010' lLLgOI.' . BY C HARl.ES A HA RT At\ HEN R.Y ALLA I\ G EASUN Ph.D. . .. • http:CHARl.ES ERRATA AND ADDENDA. Page 35, line 15, for 1854- read 1855. Page 55, line 16, for Horticultural read State Agricultural. Page 60, in second table, Illinois, for 240 read 241. Page 65, first line above foot-note, for ventricosa read ligamentina. Page 72, line 9, for imhecilis read imbecillis. Page 79, line 19, for asperimus read asperrimtts. Page 80, above Quadrula rubiginosa insert Section Fusconaia Simpson. Page 76. The record of Calkins for Margaritana margaritifera is without doubt erroneous and should be eliminated. This species is not found in Illinois. Page 95. Pomatiopsis sheldonii Pilsbry should read Amnicola sheldonii and should be transferred to the genus Amnicola on page 93. Page 100. Physa gyrina oleacea Tryon is the immature stage of Physa gyrina. Page 103. Lymncsa tazewelliana is a synonym of Lymncea parva. Page 105. Lymncea palustris michiganensis is the immature form of Lymncca rcflcxa. Page 106. Lymncza reflexa ioivensis and Lymncea reflexa crystalensis are synonyms of Lymncea reflexa. Page 112, line 6 from bottom, for goitldi read gouldii. Page 114, line 5 from bottom, for jnxtigcns read juxtidens. Page 115, line 21, for Witter read Walker; line 23, Polygyra sayii Binney should be changed to Polygyra sayana Pilsbry. Page 116, line 1. Polygyra exolcta Binney (1885) should be changed to Polygyra zaleta Binney (1837). Page 117, line 11 from bottom, for Icai read leaii; line 3 from bottom, Poly- gyra monodon fraterna is a good species and should read Polygyra fraterna. Page 119, foot-note. A specimen of alliarins in the collection of Mr. Aldrich, received from Calkins, proves to be draparnaldi. Page 121, line 3 from bottom, for Champaign read Piatt. Page 122, line 12 from bottom, for Pyramidula siriatella Anthony read Pyra- midiila cronkkitci anthonyi Pilsbry; line 4, for Held read Hald. Page 123, for Helicodiscus lineatus Say read Hclicodiscus parallcliis Say. Page 162, line 7, for glandulosa read linearis. Page 171, line 17, for riparia read vulpina. Page 176, line 8 from bottom, for canadense read majiis. Page 180, line 9, for virginica read virginiana. Page 221, line 6 from bottom, for rectangiiliis read rcctangttlaris. Page 226, line 3, for fasciatus read fasciata. Page 239, line 11, strike out Lake Co. entry. Page 246, lines 6 and 7, and page 248, lines 1, 14, 20, and 23, for CEnothera read Onagra. Page 248, line 4, for Candida Horn substitute n. sp. Pac^e 249, line 8 from bottom, for Olethreutes dimidiana Sodoff? read Olethreutes separatana Kearfott, and strike out parenthetical matter. Page 251, line 7, for grossa read thoracica; line 21, for words preceding H. 6, read Asilus rufipennis Hine; line 18 from bottom, for words preceding H. 2, substi- tute Asilus cacopilogus Hine. Page 253, line 8, for Linn, read Emory. Page 257, line 15, for pennsylvanicus DeG. read auricomus Rob. Page 261, Note 6. Melanoplus macneilli is very probably M. ftuviatilis Brun. Page 262, Note 9. Dr. Bergroth writes that Nabis elongatus is preoccupied. The original is elogantus in the check list. Comparison with long-winged vicarius is desirable before re-naming it. Page 309, in table, for 59 read 57, and for 743 read 741. Page 310, in table, for JS* read 57. Page 314, line 5, for 1587 read 481; line 16, after stubble insert meadows; line 17, after pastures strike out and meadows, and after 1600 strike out each. Page 315, last line, for 553 read 481. Page 362, line 7 from bottom, for longa read parvilamellata. Page 373. As a second entry in synonymy insert as follows: 1854. Nothrus bistriatus, Nicolet, Acariens des Environs de Paris, p. 397, PI. VII., Fig. 7. Page 376, line 13 from bottom, for Oribata read Oribates. Page 378, line 1, for XXV. read XXXV. Page 384, after line 5 insert as follows: N. bipilis Hermann. Mem. Apt., p. 95. In moss. Areola and Parker, 111. Page 384, line 5 from bottom, for pyrostigma read pyrostigmata. Page 386, after line 11 from bottom insert as follows: H. bistriata Nicolet. Acariens des Environs de Paris, p. 397, PL VII., Fig. 7. Under logs and in moss, Urbana and Areola, 111. Page 388, line 12, for sphcerulum read sphcsrida. V\IE5TERNILL1N0I5 tiJ Sand B (^/ac/o/r/afyes ',","'.'. Bluff Jin €5 V.~-' C/^lcooo Out/&t Article VII. — On the Biohxjn of the Sand Amis of Illinois. By Charles A. Hart and Henry Allan Gleason. Introduction. While located at Havana in connection with the work of the Illinois Biological Station on the Illinois River, the writer made a few trips to the tract of waste sandy land lying east of the city, locally known as the Devil's Hole. A novel fauna and flora were noted, but no systematic study of either was attempted until August, 1903, when a brief survey was made of this local- ity and of similar regions southeast and south of Havana in company with Mr. H. A. Gleason, of the Department of Botany at the University of Illinois, who studied the flora, the writer giving attention to the fauna, especially to the insect life. At the same season in the following year we made a second visit to these regions, and also examined the sandy tract lying north- east of Havana, between that city and Pekin, which culmi- nates in a remarkable barren area called the Devil's Neck. The botanical results of these two trips are presented by Mr. Gleason as the second part of this joint article. In 1905 I was enabled to make brief comparative examinations of these same regions in the early part of the season, and of similar sand areas in other parts of western Illinois in August and Septem- ber. In 1906 I paid a brief visit June 23 to the Illinois valley sand region, stopping off at Bishop, 111.; and in August spent a few days studying the sandy reaches on the flats bordering Lake Michigan above Waukegan, 111. Delays in going to press have enabled me to include herein some important data from the latter locality concerning species already on the list. The limited amount of time available for these visits enabled me merely to secure some knowledge of the abundant, varied, and largely unfamiliar insect fauna, and to develop a large crop of highly interesting biological problems for future investigation. 137 138 Part III. consists largely of some discussion of these prob- lems, followed by an annotated list of species which it is hoped may be an acceptable contribution to the knowledge of the in- sect life of Illinois. A comparison of these western Illinois areas with those of the northeastern part of the state is greatly to be desired, as the indications are that their biotas di3er con- siderably, and are derived more or less from different geograph- ical sources. In addition to the faunal studies, I have given particular attention to the topography and remarkable glacial history — especially with regard to the origin of the sand areas and their fauna—of the Illinois River valley, nearly the entire length of which I have traversed at one time or another. These subjects are treated in Part I. as a preliminary to the biological studies. The map is adapted from Leverett ('99, PI. VI.); plates XXII. and XXIII. are from photographs belonging to the State Laboratory of Natural History; and the remaining plates are- from photographs by Mr. Gleason. The authors are greatly indebted to'Professor S. A. Forbes, Director of the Illinois State Laboratory of Natural History, for his kindly interest and for the publication of this paper; and they desire to acknowledge gratefully the cordial hospi- tality and assistance of various citizens of Havana and vicinity. C. A. Hart. Fart I. Glacial Geoloc/i/ and General Characters of the Illi- nois Sand Areas, especially those of Western Illinois. By Charles A. Hart, Glacial Geology. Illinois as a land area has been subjected to at least two principal glacial invasions from the direction of Lake Michigan, the limits of these being roughly concentric with the lower end of this lake. Much of our knowledge of them is derived from the work of Leverett ('99), whose statements, supplemented by my personal observations, form the principal basis of this account. The earlier of these ice invasions, thelllinoian, apparently much more remote from the later one than this is from the present time, reached about as far west as the Mississippi River, and covered nearly all of Illinois except the northwest corner and the hill country in the extreme south. The later invasion, the Wisconsin, reached about half as far across the state. The heavy deposits of gravel, sand, and clay brought down by these ice-sheets have largely filled up and often en- tirely obliterated the previous lines of drainage. The contour of the rock surface beneath these deposits is very imperfectly known, and deserves specific investigation. Records of wells, borings, etc., show, however, that it is deeply carved by immense river valleys of which there are often no surface indications whatever. The great depth of these val- leys, usually about one hundred feet below present river levels, does not necessarily indicate a subsidence of this part of the earth, but merely the undisturbed action of water for a vast period of time, or of a greater volume for a lesser period, deep- ening them to a low gradient nearing base-level, after which the energy of the stream was mostly occupied in widening them. The Mississippi from Keokuk down and the Illinois below the bend at Hennepin are still in ancient preglacial valleys, 139 140 and apparently the entire area of Mason county lies within the boundaries of the latter valley. The highest known point of its rock surface is lower than that of any other county in Illi- nois, and fifty feet below the present level of the river. Quite probably this county lies in a forking of the preglacial valley, an eastern fork being perhaps indicated by the drainage line now occupied by Sugar Creek and the lower ends of Salt Creek and the Sangamon River, the two latter sections being in a pre- glacial valley at least four miles wide. Records of wells and coal shafts indicate great valleys beneath Bloomington and Cham- paign, and another valley leading south from Lake Michigan near the Indiana line, but at present it is impossible to trace these old drainage lines. In northwestern Illinois the Illinoian invasion evidently caused a radical readjustment of the river systems, turning them westward across adjacent divides into other valleys be- yond. (Leverett, '99, PI. XII.) The buried northward exten- sion of the preglacial Illinois valley above Hennepin is appar- ently continuous with that of Rock River above Rockford. At a point just below this city the river now leaves its evident pregla- cial channel, turning westward along side lines of its preglacial tributaries, and is still cutting narrow passages across the rock of the intervening divides. A considerable section of the Mis- sissippi was temporarily crowded over some distance into Iowa, where it has left a fairly well-marked channel that has greatly modified the course of minor streams. It now leaves its great preglacial valley not far below Fulton, 111., and runs south- west at right angles across the still evident lines of preglacial drainage, which appear to be directed eastwardly and to con- verge in that direction. In the vicinity of Rock Island the flow of both the Mississippi and Rock rivers seems to be up- stream with regard to preglacial lines, in order to cross into an- other ancient valley at Muscatine. The probability that the pre- glacial Mississippi channel swings eastward beneath the pres- ent lower Rock River valley, and thence across to the bend of the Illinois, is confirmed by the remarkably low sag, espe- cially in rock levels, along this line. In that case, it must have i4i joined the Rock River somewhere in Bureau county, and the lower Illinois valley was then part of one of the main drain- age lines of the continent. The question naturally arises as to the effect of this former relation on geographical distribution. Apparently it had none, since the entire Illinois valley was subsequently covered by the Illinoian glaciation, at which time our river systems were shifted to about their present lines. The exact rock limits of the preglacial Illinois valley are but imperfectly knowm. Apparently in obedience to the gen- eral law of the westward shift of southward-flowing streams, the present river flood-plain from Peoria down (PL V.) follows the west border of the immense valley, never very far from the west bluff, which has a rock core throughout, and exhibits practically all the few rock exposures of the lower valley. Be- low Meredosia the valley is excavated in limestone strata and is comparatively narrow, usually three or four miles wide, nar- rowing to a minimum of two and a half miles. From Meredo- sia up to Beardstown ( fifteen miles ) it widens out to six miles or more. Above Beardstown the general rock surface was ap- parently rather low originally and composed of softer strata, and the valley is enormously expanded. The low east bluff is completely concealed by subsequent deposits, yet from the Sangamon to the Mackinaw^ the original valley is probably not far from twenty miles wide. Above Peoria the limits of the rock valley are largely undetermined, for reasons given further on. The deposits of the Illinoian glaciation are not very deep. The water action seems to have been moderate, and the sur- face sand deposits caused by it in Illinois are of little conse- quence. The larger preglacial valleys, although usually tilled with these deposits to a depth of about one hundred feet, are as a rule still traceable, and are usually reoccupied by the main streams, although slight deflections are not uncommon. The terminal ridges pushed up by the ice in this period are now discontinuous, fragmentary, or entirely wanting, although often still prominent and massive. Probably the greater part 142 of the deposits which now lie between the Illinois vallej^ bluffs over the ancient rock bed are due to the lUinoian glaciation. The next ice invasion, probably the lowan, came from the northwest, and to this stage have been assigned deposits in Illinois in the vicinity of the lower Rock River watershed. It seems to have had no marked effect in our state. Long ages after the close of the Illinoian period, came an event which profoundly affected the future of Illinois, and caused, among other things, the sand deposits studied by us. The Wisconsin glacial invasion was not so extensive as the Illinoian, but it is characterized by voluminous deposits, deeply covering and almost entirely obliterating the previous surface contours; by large and continuous ridges thrown up along the terminal lines and during the successive stages of its retreat; and by abundant and powerful water action. Upon or near the terminal ridges in Illinois are the cities of Princeton, Peoria, Pekin, Atlanta, Clinton, Shelbyville, Mattoon, and Charleston. A later substage of less extent but even greater intensity was that called the Bloomington, whose terminal ridges branch off eastward near Peoria, and pass under Bloomington and Gib- son City, and to the north of Danville, 111., and Covington, Ind. The enormous outwash of sand and gravel has left more or less of its deposits in all the valleys leading away from these ridges. The west side of the rock valley above Peoria was covered by the terminal ridge to a height, near Peoria, of about 350 feet above the present river, making a total depth of about 450 feet of glacial deposits upon the bottom of the ancient rock valley. The Illinois, clogged with more than it could carry, filled its bed with sediment to a depth of about 170 feet above pres- ent levels at Peoria within the gap in the terminal ridges, and spread out in a vast detrital fan over the great expansion of the valley below, with a comparatively rapid gradient of de- scent. At the mouth of the Sangamon the filling reached about 75 feet above present levels; and at the river's mouth, about 50 feet. As the ice retreated and the water cleared, nearly all of this vast deposit was swept out of the valley, leav- 143 ing only a worked-over sandy surface, and, along the valley margins, occasional gravel terraces. The re-excavated expansion below Peoria is now about twenty miles wide between Pekin and Havana, narrowing gradually below Havana to about twelve miles near the mouth of the Sangamon, and to seven miles at Beardstown, then widening to about twelve miles in western Cass county. At this point the expansion suddenly narrows, and the valley, now in Mississippian limestones, assumes a fairly uniform width of three or four miles. The eastern border of the expansion is in- dicated by a low bluff, often obscured by subsequent wind ac- tion. Teheran, Mason county, lies at the foot of this bluff. After the ice had retreated from Hlinois but still occupied the lower lake-region and St. Lawrence valley, the upper lakes discharged for a time over the low divide at Chicago, along present drainage lines, the valley in this stage of its history be- ing called the Chicago Outlet. The clear and abundant flow ex- cavated the present river flood-plain along the western side of the valley to a depth of flfty to seventy feet below the glacial flood- plain, about thirty feet below its present level. It also spread out to some extent over the glacial flood-plain. Peoria Lake was scooped out in the comparatively narrow opening through the terminal Wisconsin ridges. Leverett ('99, PL VL) has in- dicated the existence at this time of an eastern channel below Pekin, occupying a depression now approximately followed by the line of the Chicago, Peoria and St. Louis railway from the Mackinaw River below Pekin to Havana. The Mackinaw enters this depression about ten miles south of Pekin, and, turning abruptly northward, reaches the Illinois by way of the upper end of the channel. Quiver Creek enters it near Forest City, and follows it down to the Hlinois. The railroad runs along the eastern side of the ancient island included between the two channels. The topography along this line has probably l)een altered to a considerable extent by wind action upon the loose surface deposits since the formation of the eastern channel. With the establishment of the St. Lawrence drainage the Hli- nois assumed its present size and position. The lessened flow 144 in this river, and probably in the Mississippi also, has resulted in a slight and gradual filling, in the Illinois River amounting now to twenty-five or thirty feet. Topography. The present lower Illinois River is an inconsiderable stream, normally six hundred to one thousand feet wide, flowing in a belt of very low bottom-land extensively occupied by large swamps, sloughs, and lakes. {^\. V., VI. ) This bottom-land is usually two to four miles in width, narrowest where it passes through the Wisconsin terminal ridges near Peoria and in the narrower part of the valley towards the mouth. Its naturally slow current is still further reduced by the series of govern- ment dams, permitting a deposit of soft mud over nearly the en- tire under-water surface. A few expansions occur, such as Pe- oria Lake and Havana Lake, respectively a mile and a half-mile wide, but these are shallow, and the river is gradually filling them up and building an enclosed channel down through them. On the other hand, the bottom-lands, although below normal levels for a stream of this size, are so extensive that their gen- eral filling up would require a comparatively long period of time. Doubtless under present conditions of the watershed the river is depositing silt vastly more rapidly than it did before the original prairies were broken up and drained for cultiva- tion. The remaining spaces between this modern flood-plain and the upland bluffs are occupied by the glacial flood-plain or " second bottom," thirty to fifty feet above the river and twenty to forty feet above the lower flood-plain. (PL ¥¥t.) That portion of this glacial flood-plain which occupies the great ex- pansion of the central part of the lower valley contains the principal sand deposits of the valley, and has been especially studied by us. This lies entirely between the distant low east- ern bluffs and the present flood-plain, which closely follows the west bluff. It is about seventy-five miles long, extending from the morainic border below Peoria to the vicinity of Mere- dosia, Morgan county. It occupies the southwest part of Taze- l45 well comity and extends across nearly the whole of Mason county to the Sangamon, with a maximum width of eighteen miles near the upper end, narrowing southward to about ten miles. The lower part—that below the Sangamon—forms a minor expansion of about half this width in western Cass county and the northwestern corner of Morgan county. The total area is approximately seven hundred square miles. Except for light superficial deposits its substance is largely sand, which usually reaches to considerable depths. The surface exhibits broad level areas capped by a shallow but rich soil, many of which were originally wet or swampy, but are now drained and cultivated. These alternate with large areas of surface sand—the great sand-bars of the glacial river — drifted by long-continued wind action into irregular, undulat- ing dunes, often barren and desolate, which have traveled northeastward with the prevailing winds. Frequently these dunes form long ridges parallel to the general direction of the valley. Even the bordering uplands are frequently capped with small sand-dunes and ridges which presumably came from the adjacent valley-margin. In drifting with the wind these sand masses have of course overridden to some extent the soil of the level areas, but were probably originally continuous with the underlying sands. THE SURFACE SANDS. The surface sand begins at the north with a few narrow strips along the river near Pekin, above the mouth of the Mackinaw. Below this river the sand-covered area is quite large. Only an estimate can be given of its actual extent. The governmental Soil Survey (Bonsteel, '03) reports 22,976 acres of it in southwestern Tazewell county, within a flood- plain area of about eighty square miles, or 51,200 acres. The sand therefore occupies rather more than forty percent of the total flood-plain area in this county. This ratio is doubtless larger in Mason county, which has not yet been examined by the Soil Survey, but accepting it for the entire basin of seven 146 hundred square miles, it would indicate 179,200 acres, or 280 square miles, of sand. In an agricultural state like Illinois the economic aspect of such a body of sand becomes of importance. Farm land on the neighboring uplands is valued at $100 to $150 per acre, and yields good crops of corn and oats—the grains most generally cultivated. A considerable part of the sand area also yields excellent grain crops, but in these fields patches of more or less barren or worthless sand often occur. This land is in fact much better adapted to truck crops. Much of the sand is usable only for pasture, and in Mason county alone there are thousands of acres, assessed at a one-fifth valuation of one dollar per acre, which are not used for any purpose. In no other part of central or northern Illinois, except in the larger river-bottoms, are there such extensive tracts of waste land. The surface configuration, wind action on sand, plant-cov- ering, and similar details of this sand area, are described in con- nection with the biological studies which follow. OTHER SAND AREAS. The remaining sand areas of Illinois are but imperfectly known to me as yet, but a brief statement concerning the principal ones seems desirable. The presence of sand in the soil is not sufficient to modify the character of the biota until it becomes so abundant as to affect the physical character of the surface and cause it to drift easily with the wind, when it is called blow-sand. When this point is reached, cultivation becomes difficult, and the land is usually left undisturbed even by pasturage. In ad- dition to the biotic change due directly to the excess of sand, the absence of cultivation favors the development of a rich and varied fauna and flora. A large part of the areas usually mapped as sandy do not reach this extreme stage, and are con- sequently of less interest biologically. In the large sand area of the expanded middle section of the lower Illinois valley, blow-sand is of frequent occurrence. The upper section, about fifty-five miles in length, lying with- 147 in the limits of the Wisconsin glaciation, includes but small areas of the glacial flood-plain, and these are not especially sandy, although it is stated (Leverett, '99, p. 267) that there are some dunes capping the eastern bluff-line near the upper end. The lower section, extending from Meredosia to the mouth of the river, about sixty-five miles long, is also narrow, and al- though the strips of glacial flood-plain are often quite sandy, they are, so far as I know, destitute of blow-sand. In the Mississippi River valley also, well-developed sand areas of the same general charaicter as the large Illinois River area are similarly present a little farther northward. Large tracts of sand lie on the sag over the supposed preglacial con- nection between the two rivers, and a similar very sandy glacial flood-plain extends interruptedly along the east side of the valley of the Mississippi, with small dunes capping some of the bordering uplands, from near Burlington, Iowa, up to the vicinity of Savanna, 111. Blow^-sand is known to l>e present, with all its attendant phenomena, in considerable quantities. The glacial flood-plain along this river is also quite sandy be- low Burlington over considerable distances, as far as the mouth of the Illinois, but so far as known without true blow-sand de- velopment. The blow-sand areas of these two rivers are ap- parently very similar also in organic life, and evidently should be grouped together. East of the Illinois River, along the Wisconsin morainic border, especially in eastern Illinois and in adjacent Indiana counties, there is considerable sandy outwash along the rivers, but no definite development of blow-sand is known to me. These sandy strips appear in the Sangamon valley near Niantic, along the Embarras in Cumberland and Ja,sper counties, and in the Wabash valley near Covington, Ind., and fromTerre Haute, Ind., to the mouth of the river, the sand at Covington resulting from the Bloomington glacial substage. There is an important sand area in northeastern Illinois, with considerable development of blow-sand, derived from the glacial outwash and sand beaches of the upper Kankakee val- U8 ley. It extends into northwestern Indiana, and is not far dis- tant from the dunes about the south end of Lake Michigan. It is probably similar to these in its plant and animal life, but differs definitely in this respect from the western Illinois areas, judging from published records of collections in the district. Part II. A Botanical Survef/ of the Illinois River Valleij Sand Region.*—By Henry Allan Gleason. Introductory, The ecological study of sand-dune vegetation has in recent years attracted the attention of numerous American botanists, and many noteworthy contributions to it have been made. Dune vegetation is especially well adapted to ecological inves- tigation, since the changes in the physical factors of the envi- ronment are usually considerable, the component associations are sharply distinguished, physiographic processes go on with comparatively great rapidity, and the plant inhabitants show characteristic features in habit and structure. The vegetation of the dunes bordering Lake Michigan has been studied in de- tail by Cowles, while Rydberg, and Pound and Clements have described the sand-hills of Nebraska. Intermediate in position between these two regions lie the sand deposits now to be con- sidered, and it is hoped that the matter presented may be of some value, not only in the study of sand vegetation in general, but in extending a knowledge of the origin of the prairie flora and of the relation of the forest to the prairie. The field work upon which this study is based, was carried on during the summers of 1903 and 1904, mainly in the vicinity of Havana, Mason county. Ecological Factors. The varying structure and distribution of vegetation are an expression of the various conditions to which it is subjected. Any force or condition, present or past, which has in any way an effect upon vegetation may be termed an ecological factor. The use of this term is, however, more generally restricted to * Mr. Gleason's manuscript for thia paper was filed for publication early in 1905. Its appearance has been retarded by inevitable delays in the completion of the con- tributions of Mr. Hart, it being the intention and desire of both the authors that their work should be published jointly in a single paper.— S. A. F. 149 150 those forces or conditions which have or have had direct influ- ence, and among them may be mentioned the historical factors of migration, succession, and the like; the physical factors of water, temperature, and soil; and the biotic factors, including competition, layering, and others. The various factors are by no means independent, but each influences the others and is to some degree influenced by them. The biotic and historical factors are here mentioned either incidentally or under the head- ing of phytogeography, but the physical factors are in many cases so different from those normal to other parts of Illinois that they are discussed more in detail. The physical factors which aid in the control of the vege- tation of any area have been divided by Schimper ('98, p. 174) into two groups, climatic and edaphic. The climatic factors are temperature and rainfall, and they determine respectively the specific composition of the flora and the general character of the vegetation, whether forest, prairie, or desert. Similar climatic factors are operative over broad areas, and the changes from one type of climate to another are usually very gradual. Local variations in the vegetation are due to the physical or chemical composition of the soil, to its exposure to the sun, to the available supply of water, and to other such factors, desig- nated collectively by the term edaphic. Edaphic factors are always influenced by, and are sometimes the direct result of, the climate. They are also modified to a greater or less extent by the plant-covering, as will be shown later in the discussion of the plant associations. Although the climate of thelUinoisRiver valley sand region is in every essential respect like that of other parts of central and western Illinois, a strikingly different vegetation has been developed. Receiving the same amounts of heat, light, and rainfall, and exposed to the same winds, the differences in veg- etation are due in every case to the sand in its relation to wind, moisture, and available food supply. The designation Miami fine sand has been applied by the United States Bureau of Soils to the sand composing these extensive deposits along the Illinois River, and the following 151 description of it is taken from the report of this bureau on the soil survey of Tazewell county (Bonsteel, '08). 'The sand consists of partly rounded grains of quartz stained rusty yellow or orange by iron, and made slightly loamy by the presence of silt or clay. There is no distinction between soil and subsoil. Organic matter is very deficient, as is shown in the following table giving the mechanical analysis of a sam- ple of Miami fine sand from 7| miles west of Delavan, Tazewell county. "Organic matter, 0.53% Fine sand, .25-. 1 mm., 62.20% Gravel, 2-1 mm., 0.10% Very fine sand,,. l-.05mm., 6.24% Coarse sand, 1-5 mm., 3.92% Silt, .05-.005 mm., 2.86% Medium sand,. 5-25 mm., 22.26% Clay, .005-.0001 mm., 2.42%" The soil in the depressions between the sand deposits, known as Miami loam, contains from 1.69% to 2.80% of organic matter, while other soils in the county contain as high as 4.69%- In every region where large quantities of sand are exposed, the wind plays an exceedingly important part in the ecology of the plant life. Inland it is by no means so active a factor as on or near the shores of large bodies of water, where its ve- locity is greater and the sand is less protected by a covering of vegetation. Sand blown by the wind may do considerable me- chanical injury to the leaves, young stems, and other succulent parts, but as the plants growing in the sand associations are usually adapted to it they are seldom much affected. Urowing crops, however, are sometimes badly damaged. The native plant-covering is normally sufficient to prevent much blowing, but if it is any way destroyed, large excavations called blow- outs are formed, which, as they increase in size, undermine and destroy most of the vegetation. The sand in these blowouts is so loose and easily disturbed by the wind that only a few species of plants are able to grow in it. The sand removed by the wind is deposited on the leeward 5ide in a fan-shaped heap nearly or quite bare of vegetation (PL XII., Fig. 2), or is blown on as a traveling dune. To protect themselves against this shifting of the sand, many plants are especially adapted as sand-binders, and effectually hold the sand in position. 152 Of far greater importance as an ecological factor is the sand in its relation to the water supply and, indirectly, to the sup- ply of plant food. It is a known fact that coarse soils, such as sands, have a smaller capacity for water than fine soils, the water being held as a thin film surrounding the soil par- ticles, and surface-tension being less effective over large sur- faces than over small ones. The water capacity of soils, accord- ing to experiments by Schuebler and Wollny (Warming, '96, p. 51), is least in quartz sand. Schimper ('98, p. 94) states that the water which loose sand can hold is but 13.7 percent of its own volume, while clay has a capacity of 40.9 percent. Exper- iments by the United States Bureau of soils (Whitney and Hosmer, '97, pp. 14-17) on sandy soil in Alabama showed a water content varying from maxima of 11 percent and 14 per- cent after rains to minima as low as 1 percent and .6 percent during periods of drought. This is in marked contrast with the results of similar experiments on prairie sod in Kansas, where the water content varied from a maximum of 15 percent to a minimum of 7.4 percent, and on blue-grass land in Ken- tucky, where the average content was over 20 percent, and the line of drought, at which the vegetation began to suffer, was at 15 percent. The actual size of the particles composing these soils is not stated. Warming {I. c.) quotes Wollny as saying that the water capacity of quartz sand composed of particles 1-2 mm. in diameter is only one tenth that of sand with particles .01-07 mm. in diameter. No data are as yet avail- able concerning the actual water capacity of the Miami fine sand in Illinois, but it must be much lower than that of the other soil types of the district. The power of capillary action to lift water from lower levels is also less in coarse-grained than in fine-grained soils; and in fine sand, according to Ramann (Warming, '96, p. 50), water will rise only 40 centimeters, or about 16 inches, above the surface of the ground-water. In sand with grains from .25 mm. to .1 mm. in diameter, such as constitutes 62 percent of the Miami fine sand in Mason county, water should rise by capillary attraction from 19 to 48 inches. It is evident that no 153 water could by this means be brought within reach of the smaller plants when the level of the ground-water is twenty feet or more below the surface, as it is in Mason county. The water-retaining properties of the sand are also of im- portance to the vegetation. The effect of the percolation of rain water is the saturation of the upper layers of sand to a depth dependent upon the amount of rain. If the surface is dry or only partially saturated, that will hrst be brought to full saturation, and the surplus water will sink down to lower levels. None is removed by surface drainage, so that, aside from the small quantity remaining attached to plants and other objects, all the rainfall sinks at once into the sand. Evapora- tion from the surface removes large quantities of water, but ac- cording to results obtained by King ('04, p. 159) in North Caro- lina this is less from sand than from loams or clays. By the drying out of the upper few inches a mulch of loose sand is formed, which still further reduces evaporation. King found that eight ninths of the water which might be expected to evaporate is thus retained, and that during twenty-eight days in July and August, 1902, only .205 in. evaporated from the sur- face. The climate of central Illinois during the summer is not so different from that of North Carolina as to lead us to expect here any considerable variation from the above record. The moisture in the deeper layers of sand is thus effectually con- served. After a considerable period of drought, as in August, 1894, when only .21 in. of rain had fallen in eighteen days, the sand at a depth of three inches was still moist enough to compact readily in the lingers. Thus, while the actual amount of water present is small, it is nevertheless constant, and it is a common statement of the farmers in Mason coun- ty that corn grown upon the sand is less susceptible to drought than that on the more fertile holds of loam. Accord- ing to Professor J. G. Mosier, of the Illinois Agricultural Ex- periment Station, the "firing" of corn on the sand is due to a deficiency of plant food and not to lack of water. Some inter- esting cases of other soil types, having similar but more marked powers of water conservation, are reported by Whitney ('98). 154 He describes soils in California which can mature crops with- out any rain during the growing season, and without irriga- tion. All the water held in the soil by capillary action is not available for plants, but the percentage which can be absorbed is greater in coarse-grained soils, like sand, than in those of finer texture. Experiments by Sachs showed that in a clay with a water capacity of 52,1 percent, only 44.1 percent could be used by a tobacco plant, leaving 8 percent of unavailable water; while in a sand with 20.8 percent water capacity, 19.3 percent, very nearly the whole amount present, was available. These results are substantiated in the field, plants suffering from drought in some soils with 15 percent water, while in others, of more sandy nature, they are still healthy with a water content of less than 5 percent. In contrast with the foregoing data mention should be made of the experiments of Livingston and Jensen ('04), who have shown that the fertility of the soil is dependent on the size of the component particles, and that coarseness alone "can produce sterility in spite of a plentiful supply of water." It is entirely possible, then, that the mere size of the sand particles may be an important ecological factor in the sand region along the Illinois River. But independently of the quantity of water present in the sand, the precipitation must have a marked bearing on the quantity and kind of available plant food. In all the sand re- gion, as before stated, there is no surface drainage. Water falling as rain sinks at once into the sand, and the excess is re- moved by underground drainage to the Illinois River, where it issues through countless springs along the east bank. After the heaviest rains, water may collect for a time in the blow- outs and interdunal depressions, but it soon sinks into the sand. By this rapid percolation through the upper layers of sand much of the soluble matter must be dissolved and carried down to the level of the ground-water, which in this region is never less than twenty feet below the surface (Leverett, '96, p. 759; 155 '99, p. 688), and on the higher sand-hills is certainly much lower. It is here beyond the reach of all plants except the larger trees, and they, too, must be able to live in the poorer surface sand until their roots have penetrated nearly to the level of the ground-water. The importance of the relation of food supply to vegeta- tion has probably been greatly underestimated, while too much stress has been placed on the water supply and the physical condition of the soil. Whitney and Cameron ('03) have even declared that all ordinary soils contain plant food sufficient for the growth of crops, and this may well be so in a soil contain ing relatively large amounts of calcium, potassium, magnesium, and phosphorus, even though little may be available at any one time; but in a sand composed in very large proportion of silica, the leaching action of the rainfall must ultimately tend toward the exhaustion of the plant food, leaving a residue of silica and other insoluble substances. Such has been found the case in various places. Livingston ('05, p. 26) has remarked upon the low content of soluble salts in some sands in north- ern Michigan. Graebner ('01, p. 64) has discussed the leaching action of rain on the sandy soils in Germany, and decides that the formation of heaths there is due in great part to the insuffi- cient supply of plant food. No full determinations of the solu- ble matter in the Miami fine sand have as yet been made, but, according to Professor Mosier, this sand is deficient in plant food of all kinds. The relative height of plants growing in Mason county on sand and on loam soils, certainly indicates a scarcity of plant food in the former. Indian corn tassels on the sand at a height of three to four feet; Monarda punctata is usually little over a foot high; and many other species are con- spicuously below the size reached in the neighboring woods and on the prairies. Unfortunately none of the foregoing theories has been tested by actual experiment on sand plants in the region un- der discussion, and until more definite knowledge is available, one can only believe that in general the supply of food matter 156 and the physical properties of the sand, including the size of the particles and to some extent the water content, are both of importance, and by their combined effect determine the pe- culiar type of vegetation. Direct observation alone, however, is sufficient to show that the water supply on the dunes is rea- sonably constant, and the plants owe their xerophytic habit to the rapid loss of water by transpiration, and not to a deficient soil content. The climate in these sand regions is of course similar to that of the surrounding parts of the state, and has no direct in- fluence in causing the marked differences in vegetation. Nev- ertheless, temperature is of importance in determining the flora of any region, and the mixed prairie and forest type of vegeta- tion of central and northern Illinois is to some extent the result of the seasonal distribution of rainfall. For these reasons, as well as to show the general climatic conditions of the area un- der discussion, tables showing the precipitation and tempera- ture are included. The data are taken from Hosier's "Climate of Illinois", and are given for Havana so far as observations at that place are available. The records are also given for Peoria and Springfield, Illinois, and for Keokuk, Iowa, three cities forming a triangle, with Havana and the sand region in its approximate center. It should be noted that the temperature readings are taken under the regular shelters used by the U. S. Weather Bureau, and consequently do not represent the de- gree of heat to which plants are normally subjected. Monthly and Annual Mean Temperature. Station Havana Keokuk . . . Peoria Springfield t-5 157 range in summer is 50°, but no data are available showing the daily range. The average date in the central district for the last killing frost in spring is April 21, and for the first in au- tumn, October 10, thus including a growing season of 172 days. Mean Monthly and Annual Rainfall. Station 158 across the country, by rail and on foot, is that the two are about equal in extent. THE BUNCH-GRASS ASSOCIATION. Through the prairie formation the bunch-grass association is the prevailing one, covering alike the level areas of sand and the dunes, and broken only by cultivated fields or by blowouts and blow-sand. The association derives its name from, and is characterized by, several species of grasses which grow in com- pact stools or bunches varying from a foot to two feet in diam- eter. They are not crowded so closely as to produce a sod, as in the typical Illinois prairies, but stand a little distance apart, thus making the bunch character prominent (PL XVIIE., Fig. 1). There is but little of the bunch-grass prairie remaining in its original state, most of it having been pastured with horses or cattle, which by their grazing have greatly changed the char- acter of the vegetation. Southeast of Bath there is a field which has apparently never been pastured (PI. VIII., IX.), and the following description of the original type of bunch-grass prairie is based on its character there and on small strips along the railroads. The principal grasses are Eragrostis trichodes, Stipa spartea, Panicum cognatum, and an undetermined species of Panicum. The first two species produce large loose bunches, one to two feet in diameter and almost as high, with the culms rising to a height of three to five feet. Panicum cognatum grows in dense flat bunches scarcely a foot high, exclusive of the widely spread- ing panicles, and the undetermined Panicum is even lower, with the basal leaves and culms almost prostrate. Tricuspis sesleri- oides, with loose bunches much like those of Eragrostis trichodes, is abundant in some places, especially near the edge of timber ; Calamovilfa longifoUa, with culms six feet high, occurs sparingly in patches ; and Eragrostis pectinacea, Bouteloua hirsuta, Pani- cum virgatum, Paspalum setaceum, and Sporoholus crgptandrus also produce more or less well-developed bunches. Carex grav- ida and Cgperus Schweinitzii have tufts of basal leaves from which several culms arise, and may also be grouped with the 159 Inmch-formers. Three other grasses, St/ntherlfoua jUifonnia. Aristida fuberculosa, and Cenchnts frihuloic/es, and two sedges, Ct/penis Bushil and ('. filieiilmis. are abundant, but do not foi'm bunches. The distribution of the remaining members of the associa- tion, about fifty in numl)er, is very irregular, and a group of representative species can not be chosen from them. Uosa hu- mnlis. So(i(hif/(> iH/sso/frifiisis. Aiiiorp/ia ctn/f'sccns, Opuiitid Innni- fusd, ('((Uiri'lioc frifn/f/ii/afd, and M<))Hir(/(t pin/cfafd are the most conspicuous, but as the quantitative study of the plants shows, not so numerous as TcHcrimucanddensc^OY AnihrosidpsiJostdrhyd. With the exception of Moiidn/((ptnui<(fd and the last two species, these grow in rather dense, rounded patches. The same is true to a lesser extent of almost every other species in this class, but since the individuals are smaller or less abundant, many other species may be included, or two or more patches, each with traceable outlines, may overlap. If the plants are at all conspicuous the overlapping is plainly seen, and in any case it is brought out by quantitative study of the area. This form of distribution is characteristic of associations where there are no progressive changes in any of the ecological factors, and conse- quently no zonal arrangement of the plants. Annuals with limited means of seed dispersal, and perennials spreading by rootstocks or runners, naturally grow in rounded patches un- der those conditions. It is evident, then, that while the bunch- grasses are representative, the other species, of merely local distribution, are to be considered as secondary members of the association. Table I. shows the distribution of the species in a piece of original bunch-grass prairie. The letters after each name here and in subsequent tables, indicate the number of individuals, if any, in one quadrat of one hundred square feet, d signifying 1 to 5; /;, 5-10; r, 10-25; r/, 25-50; <% 50-100;/; 100-200; //, over 200; and o, none. These counts were estimated for the most part, although care was taken to make actual counts at inter- vals in order to avoid so far as possible any serious errors of ob- servation. The quadrats in this table, as well as in all the oth- 160 er tables, were side by side, in this instance extending in a strip 110 feet long by 10 feet wide. Near the area covered by these quadrats, but not included in them, were patches of Solidago missoHviensis (r) and 7?06y/ humilis [e); c and e, as above de- fined, indicating their respective numbers per quadrat. TABLE I. ORIGINAL BUNCH-GRASS PRAIRIE. Eragrosfcis trichodes 161 Grazing results in the destruction of the larger species of bunch-formers, leaving Panicum cognatuw and the undeter- mined Paninun, PaspaJum setaceiini, ?ind Boiifeloua hirsuia as the predominant grasses. The other species, such as Eragrostis trichof/es and Sfipa spartea, so prominent in the original vege- TABLE II. PASTURED BUNCH-GRASS. (Not pastured for two years preceding count.) Bouteloua hirsuta 162 four predominant species are all small, and produce low flat bunches, giving the association an appearance widely different from the original. The sedges, especially Cyperns Schuwinitzri and Carex gravidff still persist, almost as abundantly as before. Certain other species are much more abundant, such as Monar- da punctata, Cassia chamwcrista, and Ojiuntia linmifusa, as well as the less important Polygoniun tenue, Crotonopsis glandidosa, and Foli/ga/a verfici/lata. Lept/loii ranadense and Ambrosia psUostachya are usually very abundant, but on account of their slender habit are not very conspicuous. Euphorbia Geyeri, more characteristic of blow-sand, is in some places common, and Chrysopsis ramporuui, Froelichia campestris, (Enothera rkombipet- ala, Crotoii ylandulosus, Lespedeza capitata, LitJiospermuni line- arifolium, and Coinmeliua rirginica are well distributed, but seldom plentiful. Table 11. shows the composition of the vegetation of a pas- tured bunch-grass prairie, which, however, has not been in pas- ture for two years preceding. The first quadrat is near the foot of a dune, and the survey ran up the dune, ending near its top. Table III. gives the results of a survey of a field which has been used for pasture for several years. The bunch-grass has been largely destroyed, and is replaced by Opuntia, Ambrosia, and Leptilon. THE BLOW-SAND ASSOCIATION. The bunch-grass prairie, while of a more or less permanent nature, is in no sense a climax association, but may be modified, through the action of certain physical factors on the one hand and of biotic factors on the other, along two definite and dis- tinct lines, culminating in two widely different plant associa-- tions. In the first case the wind is the principal factor, and primarily through its influence the bunch-grass association is changed into blow-sand and blowout associations and ulti- mately into a prairie. In the second case, biotic factors are of chief importance, and the prairie is finally succeeded by the black-jack forest, representing an entirely distinct formation. Wherever considerable bodies of sand occur, the wind 163 plays a prominent part in detei'mining the physiography, caus- ing migrating dunes and blowouts, where the sand shifts so readily that it remains entirely without vegetation (^Pl. XII., Fig. 1), or is colonized only by those few species able to adapt themselves to the peculiar ecological conditions (PI. XIII.) . Some resistance to the wind action is usually offered by the vegetation, so that the area occupied by the blow-sand is lim- TABLE III. PASTURED BUNCH-GRASS. (In pasture up to time of count. ) Paspalum setaceum 164 tually balanced by that deposited, and the whole remaining approximately in a state of equilibrium. On the crests of the dunes, however, where the sand is more exposed to the wind and more is blown away than is deposited, the plants are fre- quently separated by shallow excavations, and may sometimes be uprooted entirely, thereby permitting the free action of the wind, and leading to the formation of a blowout. In fields that have been pastured, there is frequently a black crust an inch or so deep formed over the surface, probably by the decay of the grass and leaves trampled into the sand by cattle. In dry weather this crust is quite hard, and effectually checks the shifting of the sand. The resistance offered by the vegetation is, indeed, very effectual, and some old settlers say that there were no blowouts in the sand region in the middle of the last century, when set- tlements were first begun, but that they haye all been formed since then. The report of the Illinois Greological Survey pub- lished in 1870 does not mention them, and it is improbable that such conspicuous blowouts as exist to-day could have escaped the attention of the State Geologist, who traveled over the country on horseback. There are, however, a few large fields of blowouts and blow-sand that have been in existence as long as the neighboring residents can remember, such as the Devil's Neck (PI. XII., Fig. 1; XIV., Fig. 1 ), north of Topeka, where a field of about eighty acres is entirely covered with blow-sand. Plowing is generally believed to be the cause of the forma- tion of blowouts, the natural vegetation being thus destroyed, and the sand left exposed to the winds of winter and spring after the cultivated crops are removed. All of the Miami loam between the sand deposits is under cultivation, and the fre- quent efforts of the farmers to extend their fields upon the dunes have often led to disastrous results. Adjacent fields of fertile soil are known to have been ruined in that way (PL XL), and at present most farmers let the sand stand unused, or use it for pasture only. It is also said that cattle may destroy the veg- etation, and that blowouts may be started in this way. When the protective covering of vegetation is once broken, 165 by whatever means, blowing proceeds rapidly, resulting in the saucer- or bowl-shaped excavations known as blowouts (Pl.VIIL, IX., XV.). Their depth may finally be as great as the depth of the sand itself, and their area is sometimes several acres in ex- tent. Their sides usually have a gentle slope, but are some- times quite steep where the bunch-grass along the crest has restricted the blowing (PI. XIV., Fig. 2). The sand removed from the blowouts is piled up on the leeward side in a more or less fan-shaped heap, and this in turn is blown on by the wind as a traveling dune (PI. XII., Fig. 2). Blowouts may be par- tially or wholly refilled by sand, being thus transformed into level tracts (PI. XIII. ), generally called blow-sand, and when these become large the individual blowouts lose their identity and the whole tract becomes a vast undulating surface of shift- ing sand. The limit of size is reached when the blowout be- comes so large that it no longer offers much resistance to the wind, or so deep that the wind does not have sufficient force to carry the sand from the bottom up over the sides, or when moister layers of sand are reached which can not be blown. In young blowouts, when the excavation is being carried on most rapidly, vegetation is very sparse, and the few species able to grow in such conditions constitute the typical blow- sand association. They are mostly plants with a short period of development, which may mature before the shifting of the sand has undermined their root-system, and they frequently possess methods of seed distribution by which they are enabled to colonize rapidly on barren areas of sand. The most charac- teristic species are Amhrosia psilostachya, Cassia chamctcr/sta, Cenchnis tribuloides, Cyclolotna atriplic{foliam,Cri^MM(i Jainesii, and Aristlda tuberculosa. Of these. Cassia and Cenchrus are the most abundant. Six to ten thousand plants of Cenchrus, none of them more than six inches high, sometimes grow on a single quadrat ten feet square, and a third of them produce seeds. Cassia prefers sand that is loose from blowing or that has been otherwise disturbed. Wagon tracks across the sand are quickly occupied by it, and are marked by long parallel lines of the plants, which are very conspicuous in the blooming season. 16() Cassia, however, can not grow upon such rapidly shifting sand as Cenchrus can, and both are surpassed in this by Cycloloma atripUcifollum. Cristatella Jamesil is absolutely confined to blow-sand (PI. XX., Fig. 1), and disappears when the blowing is stopped. Numerous other species may occur, such as Croton gUmdu- losus, Euphorbia Geyevi, Ambrosia psilostachya, Sporobolus cryp- tandrus, Mollugo verticillata, and Acerafes viridiflora. Others, less abundant, are usually relics of the bunch-grass association, the original occupant of the territory, which have persisted because their sand-binding adaptations have prevented their being undermined and blown away. Blowouts of any age may be filled up and converted into level stretches of blow-sand, covered with the blow-sand asso- ciation already described, but with more Cycloloma and less Cassia in the older ones. The vegetation is always sparse, and the blowing of the sand during the fall and winter is sufficient to prevent the perennials of the bunch-grass association from gaining a foothold. Over wide stretches of blow-sand there is frequently absolutely no vegetation, while on others there is nothing but Cycloloma, Ambrosia, Cassia, and Cenchrus. Counts in a developing blowout and in a few typical areas of blow-sand are here given. TABLE IV. SMALL BLOWOUT. Cassia chamaecrista Ambrosia psilostachya Cenchrus tribuloides Cristatella Jamesii Froelichia campestris Euphorbia Geyeri Lithospermum linearifolium Cyperus Schweinitzii Cycloloma atriplicifolium Monarda punctata * See p. 159. f*f e d d d e e e d d f e e d e d g o a b c c e o a o a a a o b o c c b o c b b b o o o b o b o o o o o a a a o a o o 16; TABLE V. 168 and numerous species of the bunch-grass may also spring up, but a new group of species appears, and by their predominance the aspect of the vegetation is entirely changed (PI. XV.). Among the first to appear is Stenophyllus caplllaris, which grows in a carpet over the flat bottom of the blowout, but never extends up the sloping sides. Its growth soon results in the formation of a thin layer of black humus over the surface. Associated with it usually are large clumps of Panicmn virga- twn and Soryhastnim avenaceum. These grasses are typical plants of damp blowouts and interdunal depressions, but re- tain their place even when the blowout is subsequently cov- ered by blow-sand. Andropogon furcatus, another grass com- mon on the black-soil prairies, is frequent, and with these her- baceous species are often associated a number of woody forms not found at all in the bunch-grass prairie or in the black-jack timber. These are Vitis vulpina, Menispermuni. canadense, Popu- lus deltoides (PI. IX.), and Acer Negundo (PI. XVII.) . All of these have effective methods of seed dispersal, and are probably disseminated widely over the sand area, but are able to effect ecesis only in these more favorable conditions. The two vines scramble over the ground, but the trees grow rapidly and, like the grasses above mentioned, persist even when the blowout is refilled with sand. The past history and position of the blow- outs are frequently shown by a large cottonwood or box-elder tree, buried in sand to its lower branches. Two species of Cla- donia soon appear, and are active as soil formers. They are not restricted to the very wettest part, as is Stenophyllus, but extend out upon the naked sand, and also occur in shallower blowouts which have never reached a condition suitable for the sedge. Following the Cladonke are Antennaria sp. and He- lianthus occidentalis, and, a little later, such other species as Hieracium longipilum, Helianthus scaberrimus, Meibomia cana- densis, Lacinaria scariosa, Mesadenia atrlplicifoUa, and others common on the black-soil prairies, and the association is con- verted into prairie scarcely distinguishable, in vegetation at least (PI. XVII.), from the typical prairies of central Illinois. A blowout succession is therefore as follows: 169 1. Cassia—Ambrosia— Cyclolortia (Blow-sand association) 2. Stenop/iijllus—Panicvm—Son/hasfrum } , , ,, , • .• x .:, p J A \ Mnlowout association) (2a. Populus—Acer) 3. Cladonia—Antennaria } 4. HeliantJrus-Hieracium ) (^^aine association) It is in onl}^ a small proportion of the numerous blowouts that this succession is followed to the culmination in a prairie. In fact, only one was observed that had reached the stage num- bered 4. Probably not more than a tenth ever reach stage 2. Although the wind alone is instrumental in the excavation of the blowouts, it has in general a leveling action. The sand removed from each blowout is distributed over a larger area than that from which it was taken, so that the tendency of the wind action is toward a level surface of sand. Reversion to B/n/e/i-gr(tss. It has just been showai that in certain cases the blow- out association may develop into one of the prairie associations. Similarly, if for any reason the blowing of the sand ceases, recol- onization is begun by the bunch -grass association. Naturally the species most active in this are those members of the bunch- grass association that are able to live on blow-sand, and partic- ularly the sand-binder Sporoholns cryptandrus (PI. XVIIL, Fig. 2). The bunch-gra.sses themselves are among the last to ap- pear, and their place is previously hlled by Co/iirrhoe frioiuju- laf(f, B/iii.s (iroitKffira, Chnjxopsis voiHponiiH, and other sand-bind- ers, or sometimes even by the Kentu cky blue-grass, Foo pra- trjtsis. Two stages in the regenera tion of the bunch-grass are shown in the following tables. Even after the sand is completely fixed, the bunch-forming grasses are much less abundant than in the normal association, their places being filled by Chnjsopsis vinnponini, Opia/fiit luitni- fi(s(f, Cdllirrhoe triangulafa, and R/t/ts (iroinatira. The blowouts may be fixed without first filling up with blow-sand, and in this case they are occupied directly by the species of the Inmch-grass association, which extend down into it, and ultimately occupy it completely. The stools growing 170 near the crest of an active blowout are constantly being un- dermined, and slide down with the loose sand towards the bot- tom (PI. XVI.). They are not killed directly by this, but are frequently seen alive near the bottom, and in this way are di- rectly available in holding the sand. TABLE Viri. BLOW SAND. (Fixation just begun.) Sporobolis cryptandrus 171 vegetation which it covers. Small trees are usually killed, but larger ones will withstand burying to a considerable depth. Frequently the only sign indicating the former position of a blowout is a cottonwood tree (PL IX.) buried to its lower limbs, but still alive. Walnut, butternut (PL X.), box-elder, and hackberry have also been observed partially buried in the same manner. The vegetation of the front of a dune which has reached such a grove (PL XX., Fig. 2) is quite different from that of a dune advancing in the open. The sand, shaded and protected from evaporation, is much moister in the upper layers, and the face of the dune is at a steeper slope. The her- baceous vegetation is sparse, probably because of the weak light, since in the sunnier spots the individual plants are more numerous. The principal species are SoIaiiioH H/fjnini, Enplior- hid heteroplujlla, Sici/os anfjulatH.s, CleiiKiti!^ Siiusi/,Part/ieiioclssi(s qninquefolia, Menisperwitm ciumdense, Ribes iHissouritn.se, AUio- tiia nyctaginea, Vitis riparia, Camp(innJ(i aineriraua, and Urtiras- trum (liniricdfiiiH. The same species occur in the valleys of the Miami loam below. Near the top various photophile forms, such as CenchrHs fribuloides, Monarda i)inict(if((, and Asvlepins s//riaca, appear in great abundance. The three first-mentioned species are evidently pronounced mesophytes, as specimens wilt very rapidly when pulled. Nevertheless, the So/aninii is finely pubescent, while the usual mesophytic form in loamy soil is nearly always glabrous. To summarize the preceding statements concerning the development of plant associations from the bunch-grass, the action of the wind may lead to the development of the blow- sand and the blowout associations, but either of them may normally revert to the bunch-grass association unless the blow- out excavation has continued until most of the sand is removed, when a normal black-soil prairie ensues. THE BLACK-JACK ASSOCIATION. Throughout the central part of the state the prairie repre- sents the most primitive plant formation. It has been shown that in the sand region,—and the same holds true throughout 172 central Illinois,—variations in local conditions may produce minor changes in the plant-covering, but that the resulting sub- sidiary associations revert in every case to the typical bunch- grass prairie. The great extent of the prairie formation, the aggressiveness vs^ith w^hich it displaces the minor associations within it, and the resistance which it offers to the encroach- ments of the forest, characterize it as a temporary climax type of vegetation. That the prairie of Illinois is, however, being rapidly displaced by the forest is no longer a matter of doubt. Cowles ('01) has shown that for the Chicago district the cul- minating, or climax, type of vegetation is the mesophytic forest. While a similar mesophile association is the climax for the central part of the state, the intermediate stages here may be very different on account of differences in the physiography or in the biotic environment. In the typical Illinois prairies the encroachment of the forest upon the prairie progresses along the drainage lines. The prairie soil always contains a sufficient amount of humus for the growth of many species of forest plants, and the succession of associations is hastened by the changes in soil and topogra- phy due to stream action. The more permanent supply of soil- moisture along the streams is a condition not found on the prairie, and this constitutes a weakness at the most critical point of its defense. In this sand region none of these favora- ble conditions is found. There is no humus in the sand, and there is no surface drainage, and consequently no erosion, no base-leveling, and no increased water supply,—all of which in other places so facilitate the extension of the forest. The hrst tree-growth that invades the sand prairies is a xerophytic association composed mainly of the black-jack oak, Quercus manjlandica, and usually known as black-jack timber (PI. XXL, Fig.l). The almost complete absence of water- courses prevents its extension in long belts paralleling streams, and, instead, it is found in large masses, w^ith more or less rounded outlines, on the larger sand deposits, or in narrow strips following the dunes. It is limited entirely to the sand, never invading the more fertile fields of Miami loam, nor en- 178 croaching upon the bottoms of the Illinois River. Besides the ))lack^jack oak, which constitutes, by rough estimate, fifty per- cent of the forest, there is about thirty-five percent of black oak, Qiicrcna rc/nf/Ha, and fifteen percent of hickory, Hicoria liiicrontrpa. These three are the only arborescent species of the black-jack timber, and in some places but one of them [QHercii.s iif((ri//(n/(/ic(f) is present. The trees seldom exceed afoot in di- ameter, and they are geherally very crooked, gnarly, and full of dead branches. The hickory is nearly always sterile, only the very largest trees producing fruit. The underbrush con- sists mainly of young trees of hickory and the two oaks, with occasional clumps of B/ms (iroindficd. Other shrubby species of less prominence occur, such as Antorjilut aiHesceHs and Sali.r frisfis. Since the ecology of the black-jack association. at least during its early stages, differs from that of the original bunch-grass association only in the smaller amount of light re- ceived by its plants, the herbaceous and shrubby flora of the two are very similar. Of the species observed on the prairie, all but thirteen were also found in the black-jack forest. These were Sparfina ci/Hosuroides, Sf/ptt sparfea, (\i/((iiH>ri/f(/ lomjifolid, SfenopJnilhts c<(piUliorJ)i(i.Jicier(>pJnj]i(i. iSicyos aiKjuhdas, Solainnu nifjnnn. and Vrficdsti-aiH dicarivaftiiu. The vegetation of Illinois, with the possible exception of the extreme southern part, has been developed since the close of the glacial period. Postglacial migration into the state has light green, short-petioled leaves which are nearly erect in a basal cluster, while in Helianthiis illiiioen.vs they are darker green, more or le?s spreading and scattered on the stem. — Ohio Naturalist, Vol. V. (1904), p. 214. 190 proceeded from three principal centers or zones: the Austro- riparian zone or Coastal plain, a U-shaped area lying along the Atlantic and (lulf coasts and the lower Mississippi valley; a southeastern center lying within the U, and a southwestern one lying to the west of it. The last two centers have furnished most of the plants of the sand region and, indeed, of Illinois as a whole, and the floral elements from them will be spoken of as the Atlantic and the Sonoran elements respectively. A northern extension of the Sonoran element has occupied the inland territory designated by Engler as the Prairie province, and an eastern arm of this province reaches across northern Illinois into Indiana. This is shown by Pound and Clements on their map of the Prairie province ('98, '00). This arm is almost surrounded on the north, east, and south by the Atlantic prov- ince, and it is also intersected along the streams by broad or narrow strips of woodland, representing the same province. When we consider also the fact that in Illinois the forests are climatic and the prairies edaphic, it is not surprising that the Sonoran floral element in the Illinois prairies is obscured by the presence of a large number of species of the Atlantic ele- ment derived from the adjacent forests. Of the 117 species growing on the prairie formation of the sand region 34, or 29 percent, are of typically western range, that is, from Illinois west across Nebraska and thence south in- to Texas, a distribution in many cases practically coincident with the Prairie province and clearly indicative of their Sono- ran origin. These are as follows: *Equisetum robustmn Stlpa spartea * Calamovilfa Jong ifolia * Bovteloua liirsuta *Eragrostis trichodes * Cyperus Schioeinitzii *Cyperus Bushii Carex gravida * Cycloloma atripUcifolium *Froeliehia (ximpestris Pe talostemon purpureus *Euphorhia Geyeri *Callirrhoe triangulata * Ojnrntia humifusa, * (Enothera rhomhipetala Asclepias Sullivantii Lith osperrmim Omelini Llthospermum linearifolium, Verbena stricta Verbena bracteosa 191 *AUionia jiyrta(/iiiea *Amhrofila pxilostaduja Anemone cylindrira Hieracunu longipilum *Lesquerella spathiiJata *Knhnia givtinosa * Crista fella JameHii *C/ir(/sopsif< rainponnii *Polanisia graveolens Solidago iiuxxoKi'ienslx Bapt'fsia hracteata HeVianthiiH .scahcrri tim.s Amorpha canesoens Coreopsif; palmata This group in the prairie formation is obscured b}^ the presence of 65 species, or 56 percent, of eastern distribution, to be regarded as derivatives of the Atlantic floral element; and the remaining 18 species, or 15 percent, include 9 of transcon- tinental distribution, 4 introduced species, S [^'Aristi(l<(fnher- culosd and ^Sporobohts crjjpiandrus) with a range along the coast of the Atlantic and Great Lakes and locally in the interior, and 8 whose range is local or unknown, namely, '''PanicHtH sp., Phlojr bifida, and Antemiaria sp. The importance of the Sonoran element can be shown to better advantage by excluding all those species which occur commonly in other associations in the state, limiting the list to the plants most characteristic of the sand region. Of the 28 species thus selected, 1 is local, 2 range along the coast and the Great Lakes, 6 are eastern or southeastern, and 19, or 68 per- cent, are western or southwestern. In the preceding list and in the paragraph following it, 22 of these species are marked with an asterisk. The 6 eastern species included are Panirum cognatuin Polygonum tenue Cyperus Micvlnii.H Monarda punctata Salij: tristis lonartis UnarlifoHxs The 66 species of the sand region which are found only in the black-jack association include 1 of local distribution, Heli- afttluis iUinoensis] 1 introduced species, C/Kf^fochloa riridi.s; 9 of western distribution; and 55 of eastern and southeastern range, indicating plainly the eastern relationships of the flora, and the floral similarity of the black-jack to the other forests of central Illinois. Of these 55, all but one, Foh/r/onum cristation, occur also in other plant associations within the state, while of 192 the 9 western species, three, starred in the following list, are practically confined to the sand region. Atherpogon curtipenduUif< Polytamia Nutfallii *Talinum rugosper/num Nahalus asper * Erysimum arkansamim. Ratibida pinnata Rihes missouriense *Artemisia caudata PetaJostemon candidus A comparison of the vegetation of the Illinois River valley sand region with that of the dunes along Lake Michigan is of interest on account of the short distance between the two re- gions. Excepting the temperature, the difference in the eco- logical conditions is scarcely sufficient to cause a wide varia- tion in the floras. The dunes of Lake Michigan, however, are essentially a beach formation, and the vegetation as described by Cowles ('99) show^s but slight relationships with the western prairies. On the beach proper only eight species occur which are common to the two dune areas, and three of these, Artemi- sia caudata, Calamovilfa longifolia, and Lithospennum Gmelini, are western in their range. The flora of the shifting dunes shows scarcely more similarity. In the established dunes the resemblances are stronger. Six species of the basswood dunes and nearly all those of the oak dunes are found also in the inland region, and Cowles's list includes Quercus velutina, Rhus aromatica, Cracca Virginia na, Oyperus Schweinitzii, Opuntia humi- fiisa, Oenothera rhomhipetala, Monarda punctata, and other spe- cies abundant on the sand along the Illinois River. In both localities these plants belong principally to the derived element; and as the adjacent forests are of the same type in both regions it is to be expected that the same species would be able to adapt themselves to the sand. It is in the endemic element that the greatest contrast lies. The dunes of Lake Michigan have no Cristate]la, Eragrostis tric.hodes, Bouteloua, Ambrosia psilostachya, Eroelicliia, Euphorhia Geyeri, Callirrhoe, or Chry- sopsis, all characteristic of the inland region; while the latter lacks Cakile americana, Corispermum hyssopifolium, Euphorhia polygonifolia, Lathyrus maritimus, Am.mophila arenaria, and 193 PnniHs piiiiiilii. representing the endemic element along the lake. A comparison with the flora of the sand-hills of Nebraska, on the other hand, shows some striking similarities. Rydberg ('95) lists 35 species as characteristic of the sand-hill region, and of these, 15, or nearly one half, grow also in the central- Illinois sand region, and this includes a number of the most al)undant species. Of the 188 species enumerated in this paper, 75. or 40 percent, are included also in Rydberg's list. It is evident from the preceding paragraphs that as a whole the flora is essentially western in its relationships. Its position within the Prairie province, as defined by Pound and Clements, can not be questioned, and the region may well be regarded as an isolated portion of the sand-hill division of the Prairie prov- ince, formed under peculiar conditions, but closely resembling the main body in its ecology and vegetation. The species found only in the black-jack oak forest are almost entirely eastern in their distribution, and have usually a wide range through the state in different plant associations. Of especial interest from a phytogeographical standpoint are Crisfafplfa Jauicsii and Lesquerelht spaflnildfa. This is the first report of their occurrence in Illinois, and, so far as known, at any station east of central Nebraska. The form- er ranges through the sand-hill region from Nebraska south into Texas, and according to Britton's Manual into Louisiana. In Nebraska it lives in almost precisely the same conditions as in this state; that is, in the bottoms of blowouts, where there is a comparatively rapid shifting of the sand In 1903 it was found in but a single blowout near Havana, and the total num- ber of individuals was probably less than five hundred. In 1904 it had spread to two other blowouts in the same field, and it was also found in great profusion in a large blowout about ten miles northeast of Havana. Lesquerella ^pafhuJata, de- scribed in 1896 from the Black Hills, ranges, according to Britton, from Nebraska to Montana and the Northwest Terri- tory. Rydberg's original plants ( '96 i grew on dry hilltops, a habitat paralleled by its growth in Illinois in the bunch-grass 194 association on some of the higliest dunes of the region. It is not mentioned by Pound and Clements in the "Phytogeography of Nebraska." It was collected in Illinois in but one station, northeast of Havana, near the second station for Gristatella. Part III. Zooloyiral Studies in the Sand Eeyions of the Illi- nois (I lid Mississippi Birer ]7(/lej/s. By Charles A. Hart. General Features. As a preliminaiT to the zoological discussion, the general topography of the principal sand areas, given in Part I. of these studies, may be briefly summarized. These areas occur on the glacial flood-plain of the broad central basin of the lower Illi- nois valley between Peoria and Meredosia,, and of the upper Mississippi from near Burlington, Iowa, to Savanna, 111., aggre- gating approximately 280 square miles in the Illinois valley alone; and considerable tracts of loose wind-blown surface sand, or ''blow-sand" (PI. X.-XV., XIX.), occur in both these areas, which in the Illinois basin are scattered in broad undulating tracts of dune formations, or in ridges running lengthwise of the valley, and reaching a maximum height of about one hun- dred feet. In Part 11. Mr. Gleason has quite fully discussed the present condition of the surface of these areas in the Illinois valley and the effects of wind action in their intimate relation to the plant covering, and a knowledge of these conditions is necessary to an understanding of the sand fauna, which, of course, consists largely of insects and their near relatives. The areas of nearly pure sand are the only ones having a dis- tinctly different flora and fauna from that of the ordinary Illi- nois prairie. They are most extensively developed upon the western half of the glacial flood-plain—the half next the present river bottom. Here there is little or no surface drainage, the rainfall being quickly absorbed. After a rain the sand soon dries perfectly at the surface, both in winter and summer, thus approximating the conditions of an arid region notwithstand- ing the greater precipitation. The striking affinities of its fauna and flora with those of the arid West are evidence of this. Nevertheless, as is more or less the case even in arid lands, the 195 196 deeper sands are always moist,—in the Illinois valley only a few inches below the dry surface layer. Much of the blow-sand is a remnant of the greater areas which existed Ijefore vegetation invaded these sands. There is little doubt, however, that attempts on the part of man to cultivate or pasture the vegetation-covered sand land have in many cases resulted disastrously and renewed the drifting ac- tion, the destruction of the plant-cover giving the wind a chance to cut in and set the sand in motion again, starting, as it were, an open sore on the face of nature. For this reason large tracts of such land have never been disturbed, and still retain their original flora and fauna; and other fields, after at- tempts at cultivation, have been allowed to go to waste. The processes for the redemption of sandy land now being devised by the United States government should be utilized here, at least to keep this sand where it is and prevent its invasion of cultivable ground. These wind excavations are called blow- outs (PI. VIII., IX.), and if large enough they soon become the windward side of an advancing dune (PI. XI.). Usually they are rounded pits, sometimes large enough to contain a house, the shifting slopes barren of vegetation, and the marginal veg- etation being undermined and swept away. When their depth becomes excessive, moisture at the bottom checks the wind action at this point, and a flora and fauna approximating the ordinary prairie type takes possession of this part of the blowout. The sand from blowouts may pile up in a barren dune or ridge, over the crest of which it drifts in a fine mist with every wind, thus steadily advancing and burying the small- er trees and bushes in its path (PL X.; XII., Fig. 2); or it may scatter out over comparatively level areas (PI. XIII.). Clumps of trees or small groves, by checking the wind and thus favor- ing the deposition of sand, occasion the formation of an active dune surrounding them on their windward side, which at least partially submerges them in the course of time (PI. XX., Fig. 2). At the earliest opportunity, however, a growth of vegeta- tion, scanty at first, tries to take possession of all blow-sand areas, thus tending to stay the drifting and to fix the surface 197 as it is. (PI. XIII.; XIV., Fig. 1; XV.) Frequently a later stage of this evolution is the growth of large tracts of a scrubby black-jack forest (PI. VIII.; XXL, Fig. 1.), and this, in turn, by the gradual formation of leaf-mold, approaches the character of the ordinary Illinois forest. Forests of the latter class (PI. XXL, Fig. 2) are especially noticeable on the fixed dune ridges which lie along the edge of the sand plain, next the river or its bottom-lands, such as the ridge extending through the city of Havana. The areas of blow-sand and black-jack are about equal, that of the final stage comparatively small. A very different and characteristic sand fauna and tiora may be found upon the constantly moist strip of sand which usually occurs along the present stream valleys at the margin of the sand plain, twenty to forty feet below its surface level, not only upon the present shores (PI. XXIII. ), but also along the line where the absorbed rainfall of the sand plain drains out upon the river bottoms at the foot of the present low mar- ginal bluff. The Localities Visited. The most remarkable sand area known to me in Illinois is in the out-of-the-way interior of the low sand plateau indicated by Leverett ( '99, PI. VI.) as an island in the channel of the Chicago outlet north of Havana (see map; also p. 143 of this article). The eastern margin of this ancient island is skirted by the Chicago, Peoria and St. Louis Railway, but from the train only a suggestion of its character appears. It is approximately five or six miles wdde and twenty miles long, having an area of about one hundred square miles. The middle third is especially sandy and almost entirely waste land. About half of this is covered with black-jack, and the other half, especially the south-central part, contains blow-sand to an extent not sur- passed anywhere else in the state, this region being locally known as the Devil's Neck (PI. XIL, Fig. 1; XIV., Fig. 1; XX., Fig. 1 ). One tract of about eighty acres is almost entirely blow- sand in successive ridges, suggesting great ocean waves in a storm. Blow-outs of unusual extent surround it on all sides, and 198 vegetation is scanty or altogether absent. The fauna and flora here are so distinctly western that this tract might almost be considered as a detached islet of the Upper Sonoran life zone. Tlie other localities most frequently visited, were (1) the Devil's Hole (PI. XIII.; XIX., Fig. 1; XX., Fig. 2), a similar but much smaller tract of blow-sand a mile or so east of Havana; (2) the exceptionally broad area of very sandy land south of Havana (PI. VIII.-XI., XV.-XVII.), with numerous small tracts of blow-sand and large bodies of black-jack timber; (3) the less sandy and better-forested submarginal ridges, often fifty feet or more in height, which extend through Havana, especially those a mile or two north of the city, in the vicinity of Quiver Lake (PI. XXL, Fig. 2); and (4) the moist sand strip at the base of the low marginal bluff of the sand plain (PI. XXIIL), saturated more or less extensively with outflowing ground-water, in part forming the east shore of the river and of bottom-land lakes bordering on the sand plain. Two additional localities, both at a considerable distance from Havana, were visited in 1905. One of these was Meredo- sia, near the southern end of the central basin, about forty-five miles below Havana. A small tract of blow-sand, with a few blowouts and some black-jack, lies immediately south of the town, and the distinctive sand fauna observed about Havana seemed well represented here also. Aside from this, there seemed to be very little blow-sand in the vicinity. The other locality was the Moline Sand Hill, described by McNeill ('91, p. 73). This extends along the Rock River, near its mouth, only a few miles from the city of Moline, on the Mississippi, just across the narrow intervening divide. It is a conspicuous elongate sand-hill, about a quarter of a mile long, near the south bank of the river. At the east end of the crest is an acre or two of undisturbed waste land, with a group of several good- sized blowouts, bordered by a small fringe of willow and Caro- lina poplar on the east slope of the hill. The sand is here ap- parently finer than at Havana. The fauna differs slightly from that of the Illinois valley regions, but not to any marked de- gree. While there are other and larger blow-sand areas in this 199 part of the Mississippi valley, none of them are in this immedi- ate vicinity, and it seems remarkable that the distinctive sand fauna should be so well represented in so restricted an area. Geographical Distribution of the Species. Professor A. P. Morse has truthfully said of the Acrid'ddce ('99, p. 332): "Locust distribution is primarily and very dis- tinctly climatal in character. * * * In its details it is influ- enced to a very high degree by physiography and its attendant conditions, such as character of the soil, humidity, etc. In its broader features it is eminently characteristic of life zones and regions. * * * It is in many cases dependent on and con- firmatory of geological changes. For these reasons and those noted at the beginning, viz., wide distribution, terrestrial and conspicuous habits, numerical abundance, size, etc., the family and its distribution are of high importance in a study of life zones in their relation to agriculture, and of faunal regions in their relation to general science." The Acrid ii(J<(' of the sand region received my especial at- tention, and, fortunately, the work of Blatchley ('03), Bruner ('97), and Gillette ('04) has furnished very satisfactory lists for a comparison of species with those of neighboring states in the same faunal zone. There are now known from the United States and Canada, in round numbers, about 650 Acridiidce. Blatchley has listed 64 in Indiana. McNeill's Illinois list ('91) was somewhat incom- plete, and contained only 55 species. Our present Illinois list numbers about 78 species, to which may properly be added for this discussion four species found by Blatchley near the Illinois line, but which we have not yet searched for in the same kind of situations near by on our side of the line. This makes a practical total of 82 species for Illinois. Conversely, we have found in eastern Illinois, although not near the boundary line, two species which probably occur in Indiana, though not listed by Blatchley. Bruner has recorded 1 50 species in Nebraska, and Gillette 133 for Colorado. Groups of species variously recog- nized by different authors have been equalized in these counts. 200 We have, then, as the nearest approximation to the truth at- tainable at the present time: Indiana, 66 species, Nebraska, 150 species, Illinois, 82 species, Colorado, 133 species. The excess in Illinois as compared with Indiana is very largely due to its western sand districts; while the great varie- ty in Nebraska may properly be ascribed to its wide range of soil and climate, from the humid Missouri valley to the arid sand hills of its western part. The suitability of an arid environment for acridiid development is also evident in these figures. A com- parison of the species of the three states first mentioned shows that with the exclusion of the Tettigime, which cannot be accu- rately compared at present, Nebraska contains nearly all the spe- cies of Indiana and Illinois, and Illinois probably nearly all of those of Indiana. Ten species of Illinois or Indiana do not occur in Nebraska lists. These include two quite rare Illinois species, MecosMhus plafypfe7-ns SLYid Melunoplus walshi; ^\q worihQvn spe- cies, Trlmerotropis maritlma, Paroxya scudderi, and P. hoosteri, Melanoplns extremus, and M. islandicus, the last three of which have not yet been taken in Illinois; and three southern species, Trimerotropis f^axafilis, Erltettix viygatn^, and MeJatioplus im- pudicus, the first two not yet taken in Indiana. The Arn'diidw of Champaign county in the vicinity of the University of Illinois have received a great deal of attention, and 82 species have been taken. This is a typical series of the ordinary prairie and forest, not only of east-central Illinois, but also of Indiana, of western Illinois, and of at least the ad- jacent parts of Missouri and Iowa. These species should cer- tainly be found in the Illinois River valley, as there is no lack of suitable situations for all; they have merely not yet been searched for, except in the sand region. There, 19 of them are known to occur, and the same region, moreover, has 26 species not yet found in Champaign county and not likely to be found there, making an actual total of 45 (about one half more than in Champaign county), and a probable total for the central lower valley of 58—nearly twice that of Champaign county. 201 Selecting the more distinctive sand Orthoptera of the Illi- nois valley district, only three of which {Syrhula adniirahilis, SpharagenioH boUi and Mclanoplus (dlfuiis) have been found in Champaign county in dry situations, and comparing them with those of other sand regions, the results are especially significant. The principal sand areas examined by Blatchley were two: the area of northeastern Indiana near the lower end of Lake Mich- igan, and that of the Wisconsin morainic outwash in Vigo county, southern Indiana, near Terre Haute. Opportunity is thus afforded for a triangular comparison, the Illinois locality being about midway betw^een the two in latitude. There are 36 species in the comparison, 32 of w^hich are in the Illinois district, 17 in the lake region, and 12 in Vigo county. Only four of the list are common to all three localities, but that is apparently because the Vigo county area is not so sandy as the others, these four being species of dry, but not necessarily sandy, ground. They are Spharagemon bolli Melanoplus atlanis Schistocerca alutacea MelanopluH luridus Five more Vigo county species occur also on the Illinois valley sand, but are not recorded from the Indiana lake region. These are Tettix arenosHs Melanoplus unpudicux Syrhula admirahilis Melanoplus minor Ageneotettix scudderi The presence of .1. scudderi and M. minor in this series is a little strange; the others increase in numbers southward and hence w^ere not found in the more northern situation. One species {Nomofeffix compressus) common to the two Indiana localities, although it occurs also in Illinois, has not yet been taken in the Illinois valley sand region. Of the species common to the Illinois valley and the Indi- ana lake region there are 11 not found in Vigo county, most of them decided sand lovers. The four marked with a star are at or near the eastern limit of their range; the others reach the Atlantic coast states. The list is as follows: 202 Orphulella pelidna Psinidia fenestralis Orphulella speciosa Hesperotettix pratensis *Hippiscus tiiberciilatus Melanoplus fasciatus *Hippiscus lialdemanii *Melanoplus angustipennis Spharagemon Wyoming- *Phoetaliotes nebrascensis ianum Gonocephalus Tohiistus Of the species known from only one of the three localities, there are in Vigo county two, CeuiliopJiilus Jatens and ulileri, inhabiting dry sandy ground; in the lake region there is just one species, GryUns arenosus, which seems peculiar to that region; and in the Illinois locality twelve have been found, the range of several of these species being extended to a very unexpected degree by their discovery here. Their previously known range is given in the appended list, which shows clearly the alliance of this sand fauna with that of the Great Plains. Mermiria neomexicana. Wyoming to N. M., Neb. to Tex. "Rocky Mts. to Miss. R." Mermiria hivittata. Fla., N. J., Kan., Utah, N. M., Tex., and intervening states. Lower Austral (Morse), 111.? (McNeill). Eritettix virgatus. Tex., Ark. Amphitornus hicolor. "Mont, to Kan." A characteristic spe- cies of the Great Plains (Bruner). Hippiscus phoenicopter us. "Southern U.S. eastof Great Plains." Moline, 111. TrachyrlxacTiis thomasi. "Upper Miss. Valley and Colorado." S. 111. (Thom.). Ky., Ind. Classed by Blatchley as Austro- riparian. Its records are confused with those of other spe- cies, but it probably occurs also from Minn, to Neb. Campylacantha olivacea. Neb. to Tex. S. W. Ark. CampylacantJia acutipennis . Tex., Kan. Hesperotettix speciosus. "Rocky Mts. to Miss. R." Neb. to Tex. N. M. Melanophis liavidus. Ariz., N. M., Tex., Kan., Col., S. W. Neb., Mont. N. W. 111. (McNeill). Udeopsyllarolusta. "W. of Miss. R." Iowa (Osborn). Oryllus personatus. Ariz., N. M., Tex., Col., Kan., Neb. 203 It now remains to compare the Illinois sand regions with the sand-hills of western Nebraska. Unfortunately, I have not a definite list for the latter locality. The general Nebraska list shows that all the Arridiida' of the Illinois valley sand dis- trict are found in that state with the exception of the southern MeJanophis imijudicus and Er'dettix riryafus, and about half of them in the western part, but that a number of additional sand species appear in that part of the state. As to the intervening states, Missouri and Iowa, we have only an old list of about 41 Acrid iid(r for low^a (Osborn '92), in which 19 of the 30 Illinois- Nebraska sand species are lacking. Further knowledge of the Orthoptera of these states is very desirable. The occurrence of Melanoplus impudicns and Eriteftix rlrgafus in our district gives force to Morse's suggestion ( '99, p. 316) that a southern species of sandy or light-soil situations may have a more elastic north- ern limit than one of damp and heavy soil. So far, therefore, as the Orthopfera are concerned, the evi- dence indicates that the fauna of the Illinois valley sand region has much stronger western affinities than that of the south end of Lake Michigan; that it is quite closely allied with that of the eastern part of Nebraska, which is within the Carolinian life zone, but can hardly be called Sonoran; and that it is of western derivation, and migrated eastward, probably by way of the glacial outwash in Iowa, at an early period. Our entire list of western Illinois sand insects numbers 596 species. From these has been selected the following list of 85 species which seem to be not generally distributed east of the Rocky Mountains. These, of course, are the significant ones in a study of distribution. They fall into six classes with regard to the extent and direction of their range outside of western Illi- nois, the scattering, the local, the northern, the southern, the eastern, and the western species, and are correspondingly listed in this connection as being of especial interest, a summary state- ment of their previously known distribution being appended to each species. The last two groups are divided into near and distant species, the distinction being based on their presence or absence, so far as known, in states adjoining Illinois. 204 Each locality record from the collections of the Illinois State Laboratory of Natural History is separately indicated by the letter I, and from the Bolter Collection of Insects by B. SCATTERING SPECIES (4). Zuphlum longicolle, Cal., Tex., Ohio (B). Adalia hipunctata. Can. and N. S., south to N. J., west to Neb. ; Col. to Ariz. Until the last few years practically unknown in Illinois; now frequent. Lucanus placidus. Pa., 111., Ark. (I), Minn. (B). Lema cormita. S. C, Kan., N. W. Ind. LOCAL SPECIES (8). Bacunculus hlatchleyi. Ind., Wis. (B). [Throughout 111.] Melanoplus inactieilli, n. sp. [Rock Island Co.] Nobis elongatus^ n. sp. [Mason Co.] Harpalini^ sp. [Rock Island Co.] Harpalus testaceus. la.. 111. Meroptera cviatella. Cook Co. Sphcerophthalma chlamydata. Mason Co. Ammophila argentata^ n. sp. [Mason Co.] NORTHERN SPECIES (2). Melanoplus fasciatus. Can., north half U. S., south limit N. J., Pa., Ind., Mo. to Col. Melanoplus minor. Can., north half of U. S., Okl. and Ariz. SOUTHERN SPECIES (11). Ischnoptera incequalis. Ga., Ind. and Tex., to C. Am. Mermiria Mvittata. Fla. to N. J., thence to Utah and N. M.,Kan. to Tex., 111.? HippisGus phoenicopterus . S. U. S. east of Great Plains, S. 111., S. Ind. to N. J. Melanoplus impudicus. N. J., S. C, and Ga., to S. Ind. and Ark. Cicada marginata. N. J. to Utah, S. 111., and southward. Tettigia Jiieroglyphica . N. J. to Mex. Tex. (B). Carahus syhosus. Mass. (I)., N. Y. to Tex., Kan. (I)., 111. Saprinus ferrugineus. Tex., Fla. (B). 205 ChalcodermuM collarh. N. J., D. C, Va. (B), Ky. (B), Fla. (B),Tex. Xanthoptera .semi/fava. S. States, N. J. to Tex. Bemlidf'la capiioptera. Ga., Ky., Tex. EASTERN SPECIES (13). Near (9). Sphceridiuni scarahceoides . Atl. Coast to Chicago. [Rock Island Co.] Introduced. Clerus thoracicus. Pa. (I ), D. C, N. J., N. Y. (B ), 111. Opatrinus notus. Pa., D. C, N. J., 111., Ind. Chalepus smithi {Odontota horni). Mass., N. J., D. C, N.E. 111., N.W. Ind. Scotohates calcaratus. Vt., N. J., D. C, Mich. (B), La. (B), 111. Xylovinus saperdioides. Miss. K. east to Fla. (B) and Vt. (I) ; Wis. (B). Proetacanthus hrevipennis . N. J. to Fla., Ky. Sphmrophthalma harmonia. Mass. to Fla., Ind. Epeolus pusilhis. N. H., Mass., N. J., 111. Distant (4). Mecostethiis platypterus. N. Eng. Pentatoma juniperina. E. States north of N. J., thence into Can.; Col.; Duluth, Minn. (I). Ualtica fuscocenea. Mass., Ga. Psilocephala pictipennis. N. J., Ga., Fla. WESTERN SPECIES (47). Near (16). Mermiria neomexicana. "Rocky Mts. to Miss. R.", Neb. to Tex., Wyo. to N. M. Hippiscus haldemanii. N. W. Ind. to the Rocky Mts., N. M. Hesperotettix pratensis. Fla., N. W. Ind., S. 111., Ark. to la. and west to Cal. Hesperotettix speciosus. Miss. R. to Rocky Mts., Neb. to Tex., N. M., S. 111. prairie (I). Melanoplus liavidiis. N. W. 111. ; S. W. Neb., Kan., Tex. and Ariz, to Mont. 206 Melanophis angustipennis . S. E. Ind., la. to Kan. and Mont., Tex. Phoetaliotes nehrascensis. N. W. Ind., N. W. 111., la., Tex. to Alberta. Udeopsylla robusta. "W. of Miss. R.", la., N. M. Cicada dorsata. 111. to Tex., la., Kan., Col. Nothopus zahroides. "Western States", 0. 111., la., L. Sup. (B), Neb. (B), Ool. to Ariz, and N. M. Lacon rectangularis. Ind. and 111. to Col.; Kan., Tex. (B), S. States. Ghrysomela auripennis. N. W. Ind., Fla. (B ), Neb. to Tex., Col. Heliocheilus paradoxus. "Mid. Miss. Valley, south and west." Col., Tex. Olethreutes dimidiana. Mo. (Identification doubtful.) Anthrax halcyon. Ind. to N. D., and Ariz. letralonia dilecta. III. (Robertson), Kan., Col., Tex., N. M. Distant (31). Eritettix virgatus. Ark., Tex. Amphitornus bicolor. Mont, to Kan. Campylacantha oUvacea. S. W. Ark., Neb. to Tex., S. 111. prai- rie (I). Oryllus personatus. Neb., Kan., Col., Tex. to Ariz. Sinea confusa. Tex., Ariz., Oal. Zelus socius. Dak., Kan., Tex., Ariz., Col., Id., Cal. Zelus renardi. "W. St.", Cal. (The next four species have each a single eastern record, l)robably in areas similar to the Illinois sand region.) Stachyocnemis apicalis. Dak., Tex., Mex., Cal. Fla. Catorhintha mendica. I. T. and Col. to C. Am., Dak., Cal. Fla. Cydnus ohliquus. Col., Utah, Tex. to Cal., Mex. N. Y. Gorimelmna ciliata. Kan., Col., Greg., Cal. Fla. Brachynemurus irregularis. Tex. Havana (Currie). Myrmeleon immaculatus occidentalis. La., Col., Nev., Ariz., N. M. Havana (Currie). 207 Polyphylla hammondi. Tex. to Ariz. Mecas pergvata. Dak to Tex., Ool., Kan., and N. M. (B),S. 111. prairie (I). Metachroma angastuluiu. Mont. Metachroma parallelum. Mont., Kan. Epitragus acutus. Kan., Tex., Mex. Phacepholis Candida. Kan., Col., Tex. and N. M. (B). Acontia lactipennis. Tex. Crambus haytiellus. Tex., Hayti. Asilus angustifrons. Wash. Rhadiurgus leucopogon. Neb., S. D. Zodion ohliquefasciatum. 8. D., Kan., Tex. to Ariz., Mex., Mont., Wash. Chelomis anglieri. Neb. Sph(]e}'ophthalma J,.-guttata. Kan., Tex. Trielis octomaculata. Ark. Odynerus geminatus. Tex. Anthophilus pulchellus. Col. Tachytes texanus. Tex. It will be seen that the above general list fully bears out the inference drawn from the Orf/topfera alone that the deriva- tion of this sand fauna is predominantly western. Of 85 species, in all, which are not of general distribution, and which, there- fore, according to Morse, are of especial value in studying fau- nal differentiation, 73 range in some definite direction from the sand region. Less than three percent of these (2 species) can be classed as northern, and neither of these is confined to sandy land. Over 14 percent (11 species) are southern, the in- crease over the northern species being related to the southward extension of the Great Plains fauna. The range of several on this list seems to be imperfectly defined. Eighteen percent (13 species) are eastern species, one of them {SplKrridiuin scara- keoides) lately introduced, and its western limit carried by this record still farther westward. Several of these are apparently rare species, really of larger range. PenMoma jauiperina, Chah- 208 pus smlthi, Opafrhius notus. and Sphftropthahna harnionia, are probably true eastern species, the Fentafoma a.nd Ojjotrin us giv- ing way in the arid region to other dominant species, though the former has lately been found to occur in Colorado. Sixty-four percent (47 species) are western, most of them definitely so, and over 42 percent (31 species) have not even been recorded from any adjacent state.* Four of the HeterojHera , however, have each been listed once at the Atlantic coast, three of them in Florida; and there is no apparent reason, except that of greater distance, why the eastern sand areas should not acquire species of the arid West in the same way as is assumed for Illinois. Several species of the Illinois valley sand region — Campy- lacantha olivacea, Hesperotettlx pratensiSj H. speciosus, and Schis- tocerca alidacea—are not rare on the dry soils of the Illinoian glaciation in southern Illinois, and last season (1905) the Cani- pijlacantha w^as actually abundant there, in both the w^estern and the eastern portions, on the common Ambrosia of that district, A. hideufcda. These species probably do not exist on the black soil of central Illinois. The presence in the Illinois valley sand region, as reported by Mr. Gleason, of several characteristic plants of the Great Plains flora, would doubtless attract their own insect fauna, and thus may directly account for the presence of a number of insect species. Sand as a Factor of Animal Environment. It has already been stated herein that the presence of sand in the soil has little effect on the fauna—and this is true of the flora also—until the sand reaches a stage of purity which per- mits it to dry readily and to drift gradually with the wind, in which condition it is called blow-sand; and that except for brief periods at times of rain or melting snow, this is dry and loose at the surface, but always moist a short distance below. In what way these blow-sand conditions have so marked * A comparison of these data with those independently obtained from the flora by Mr. Gleason, on p. 191, second paragraph, will be of especial interest. 209 an influence on the character of the biota is not very evident. The fact that some organisms are attracted by the presence of others, only complicates the problem. After casting about for species that appeared to be directly influenced by these condi- tions with the least likelihood of complications of any kind, 1 selected the acridiid genus MeUniopIu^. Just v^hy M. flcwidus should occur only in the most barren blow-sand situations while M. feiiiKr-ruhrum seems interdicted by even a suggestion of blow-sand, seems at first sight almost unaccountable. Fac- tors which might possibly have an influence in this case are (1) food supply, (2) moisture, (3) temperature, (4) sparseness of vegetation, (5) the mechanical effect of sand, by its drifting, etc., (6) protection, (7) competition, and (8) the effect of sand on the immature stages. Considering these factors successively, the matter of food supply might be expected to solve the problem, since McNeill ( '91, p. 75, M. ceHchri) found fiavidus constantly associated with the sand-bur {Cenchna^) which grows on sandy ground; but the sand-bur is locally vastly more wide-spread than Jiavidus, and in our field-work y/r//;/(/«.s' was found in blowouts whether sand- burs were present there or not. Morse ('99, p. 315) says that the food question with grasshoppers is a matter of quantity rather than quality, indicating that they have bat little pref- erence as to food supply. As to the subject of moisture, there is doubtless at times much difference between sand and ordinary soil in this respect. Capillary action is stronger in ordinary soil, which therefore dries out more deeply, and at the surface more slowly, than sand; but ultimately one is as dry as the other. The factor of atmospheric humidity at close range with the soil may have some influence upon these geoph- ilous species, as its variations over sand and earth would doubt- less be expressed by quite unlike curves. With regard to the direct water supply of these insects it must be remembered that they drink dew only, which is at least not noticeably de- ficient over our sand regions as compared with prairie soils. The third consideration also, that of temperature, presents only vague possibilities which seem insufficient to limit the local 210 range of these species. In clear weather the temperature over the blow-sand is probably higher by day and lower at night than in the case of ordinary soil, but the difference in this respect can not be great between some grassy tops of sand-hills occupied hy Jiavidus and a close-cropped prairie pasture where femur-ruhrum abounds. With regard to the sparseness of the vegetation usual on sand-dune tops, this can hardly be an influ- ential factor, as it is not a constant feature of the areas known to be occupied by fiav'ulus', and the mechanical effect of drift- ing or loose sand upon such active insects with so well-devel- oped an exoskeleton,is surely of little consequence to them. As to protective coloration, both of these species are protectively colored. McNeill ('91) notes the strongly imitative colora- tion oi flavklus on sand; feniur-rubruni is slightly darker above than flavidus, and therefore better suited to an ordinary soil surface; but, in any case, protective coloration is an effect rather than a cause. Insects which are adapted to ob- tain food in exposed situations usually approximate the ap- pearance and color of something in their normal surround- ings, but surely do not flt themselves in wherever their original coloration matches best. The next factor, competition for space, is suggested in explanation of the limitation to sand of insects such Sisfavidus, the idea being that they are species also fitted for existence in more favored situations, but simply unable to hold their own there in competition with other spe- cies such as femnr-ruhyuyn. The facts of general and local dis- tribution, however, do not support any such idea. Lastly, the effect of sand on the immature stages comes up for considera- tion. This is an important factor, analogous to taking root and dissemination among plants, and may ultimately prove to have a considerable influence on local distribution; but we have no data as to these stages in flavidus. Grasshoppers ordi- narily choose a rather hard soil in which to place their egg mass- es, and excavations in sand are not maintained with the same facility as in earth without special adaptations for the purpose. In general, therefore, it may be said that while there are a number of minor differences in the biotic environment on 211 blow-sand and ordinary soil which further observation and ex- periment may show to have a controlling influence on the local distribution of species, these factors do not, so far as our pres- ent information goes, satisfactorily account for the observed peculiarities of specific distribution. The Relation of Sand and Climate to Insect Coloration. One of the most evident color adaptations among sand in- sects is that of direct imitation of the color effect of the sand. The exposed condition of insects upon any surface where the vegetation is more or less scanty makes it advantageous that all species existing there and lacking other means of protec- tion should be as inconspicuous as possible; and species on our list belonging to various orders, have developed remarkably pale dorsal colors, apparently for this reason. In the case of the Carolina grasshopper {Dissosteira caroliNa), which inhabits not only the sand surfaces in this district but also the darker bare surfaces, individuals taken on the sand seemed to show a decided approximation towards its color when compared with those from darker ground in Champaign county. Vosseler, who has studied out and described in detail the fundamental pattern of the Acridiidw ('02, Bd. 17, p. 22), calls attention to the fact that the molting occurs in daylight, and that the nearly col- orless fresh exterior is then exposed to the action of reflected rays from surrounding surfaces, which, he suggests, may in some way, by photographic action, produce an approximation to their general color. How this can occur is not clear, but Poulton's experiments on Lejjidopfera, and various other obser- vations, all point to some such effect. The observations con- cerning the Carolina grasshoppers above recorded (made before reading Vosseler's paper) , and the great differences in the ground color of individuals of this species can be satisfactorily account- ed for only in this way. The more evident examples of sand imitation are the pale brown of HarpaJus fesfaceus, H. erraficus, and Geopinus incrassa- tns, the broad white markings of Cicindela lepida and Tetra- gonoderus fasciatiis, the ashy grays of Sfachi/ocnemis and Emhle- 212 this (jr/seut;, the brown coloi' of GnjUus jjermKutus and Udeop- sylla rohusta, and the remarkable approximation to sand-color effects in Trimerotropis r/fr/na, Spharafiemon iri/ommgianum, and other Acrid iidri'. The subject of the protective colorations of the phytophi- lous species is an extensive one, and not closely related to the subject under discussion. The phytophilous, yet undoubtedly xerophilous, green grasshoppers of the genera Camp)}/ 1acantha and Hespeyotcttix provoke additional questions as to the envi- ronmental factors which limit them to dry soils. Corimelcena ciliata, both phytocolous and arenicolous, unless protected by the usual "bug" odor or flavor, may escape its enemies by what Dr. Forbes has called a resemblance to nothing in particular; and apparently the same is true of the Tenehrionidw. It is per- haps going a little too far, however, to tell here that I was once, for a moment, completely deceived on seeing Bhyssematus lineaticollis lying in the axil of a milkweed leaf alongside a rail- road track, by its exact resemblance to a locomotive cinder. A type of coloration quite opposed to mimicry is that of the non-sympathetic, or contrasting and conspicuous, colors. Examples of this type are seen in the bright colors—presuma- bly serving as a warning—of certain exposed sand insects oth- erwise protected, such as the stinging Mutillidce a,nd Bern becidce, the bug PeriUus circumcinctus, and some of the tiger-beetles [CicAndelidw). A curious fact was noted with regard to the large female mutillid, SphcpropldhaJma occidcntalis. This is not rare in southern Illinois and is of the usual bright scarlet color. So also is an example from Meredosia; but the six indi- viduals captured near Havana were all of a faded golden-ochre- ous tint when taken. The latter locality is about its northern limit, and we have never taken it elsewhere in central Illinois. Other species are apparently colored in imitation of the preceding class. Phidippus insolens, a spider of the blow-sand, is colored and shaped in close imitation of a mutillid. Laphys- tia 6-fasciata, a fly of the blowout pits, resembles a sand wasp {Microbembex monodonta) of the same situations both in actions and appearance. Vohicella fascirda, a very prettily striped syr- 213 phid fly common in these sand regions, resembles a wasp. A marked case of imitation was that of CJieJonus fexanus, flitting in sparse low vegetation in company with an undescribed Schizoceriis, and with difficulty distinguishable from it while in action. The non-sympathetic colors of the Acridiidie, such as those of the hind wings and hind tibiae, are of unusual interest, es- pecially as they seem to be subject to alteration—to a varying degree in different species but always in the same direction — as the effect of certain climatic influences, apparently that of the degree of humidity, or of humidity and temperature com- bined. The bright colors of the hind wings, especially noticeable in the (Edipodince, are curiously at variance with the modest protective tints of the insect at rest. Vosseler suggests that these rainbow hues, which rival in brightness even those of the Lepidoptera, constitute a "contrast-mimicry." While the pur- suer is dazzled by the flashing colors, the wings are suddenly closed, and the insect settles quietly to the ground, all track of it being lost in a monotony of color. The genus C(doca/a, among the Lepidoptera, is apparently an exactly parallel case. These depend for protection on the close resemblance of the fore wings to the bark of the trees on which they rest. It would seem, however, from the data which follow, that any explana- tion of the origin of the hind-wing colors of Orthopfera should apply to those of the hind tibiae also. Bruner ('93) has pointed out that red-winged species—and he might have also said individuals—of grasshoppers are most common in humid regions, and yellow-winged ones in more or less arid regions; that in mountainous regions "just between the dry and wet conditions" blue-winged forms occur; and that from the Atlantic coast to the eastern edge of the Great Plains red or orange is the characteristic color, while on the plains and in other arid districts west and southwest these give way almost entirely to yellow. In Illinois the hind wings of Hipplscas tuberculatum and H. phcetiicopterus are red, rarely yellow. Those of our common 214 and only prairie species, H. rugosus, and also those of H. halde- inanii, show a wide variation from bright red to nearly white. The variation is usually discontinuous, there being three or four fairly distinct colors: red, pinkish, yellow, and yellowish white. Our collections of rugosus in the Illinois State Labora- tory of Natural History, mostly from the humid prairie of cen- tral Illinois, were classed as red and yellow. There are 141 7-ugo- sus in all, 37 red-winged and 104 yellow, the latter number in- cluding 46 taken in 1905, of which 15 were clear yellow, and 31, taken mostly on the drier southern Illinois soils, w^ere pale whitish yellow. HalclemanH from the sand region in 1905 were 22 red, 1 pinkish, and 9 yellow. Hippiscus tuhercidatus and Psinidla fenestralis, normally red-winged in Illinois, are yellow- winged in the West. The only species variable in wing color and common in both the Illinois sand regions and on the humid prairie are Hippiscus rugosus and Arphia xantJioptera, but I have not at present a sufficient number of these from each locality for comparison. The facts at hand warrant the conclusion that while the species of a given locality, and even the individuals of a species, may differ greatly among themselves in regard to wing color- ation, the general tendency of arid climates to replace red with yellow and, under certain circumstances, yellow with blue, is too evident to be questioned. A very similar effect upon tibial coloration is even more ev- ident, and I have taken especial pains to collect evidence on this point. A notable series showing a direct influence of the blow- sand environment—virtually equivalent to climatic influence — upon species within a short distance of each other, is afforded in the genus Melanoplus by nearly every active sand-dune ex- amined by us. In the first place, on the least sandy areas in the nearest level cultivated ground, the dominant Melanoplus is femur-rubrum, always with bright coral-red hind tibi*. Sec- ondly, on the drier and more sandy grassy ground of the base or lower slope of the dune we find it replaced by M. atlanis and M. minor. Atlanis is here unusually variable in tibial color. Most frequently it is red, as in fetnur-rubrtmi; sometimes paler. 215 even pinkish, with bluish at base; or else bluish green, apically yellowish or pinkish, the bluish green varying slightly towards blue or green; or even yellowish. The difference between red or salmon-pink, on the one hand, and the bluish to yellowish tints on the other, is generally well marked. Of 70 specimens of this species quite indiscriminately collected in the sand re- gion, 46 had reddish tibiae, and 24 were of the blue-green or yellow type—about one third of all, therefore, not being red. The 46 red ones were 23 males and 23 females; the 24 blue- green ones, 11 males and 13 females,—indicating that in this spe- cies at least the sexes are evenly divided in this particular. Twenty specimens of minor taken, had the tibiae either green- ish blue or coral-red, without intergrades, 12 of these bluish and 8 red. Only five of these were males, all with bluish tibise. Thirdly, on the upper parts of the dunes, where loose sand and tufted growths begin (PI. XVIII., Fig. 1 ), these species are replaced by swarms of M. angustipennis. This has clear blue tibiae, rarely coral-red. A continuous search for examples with red tibiae in this situation yielded only two specimens, both undoubted angustipennis, one of each sex. The number of this species taken was 125. Lastly, as one approaches and en- ters the wind-excavated hollows of the apex, M. Jiavidns be- comes most abundant. This invariably has tibiae of a brilliant and beautiful blue, approaching the shade of cobalt-blue. In the dense black-jack oak brush which irregularly covers large areas of these sands (PL XXL, Fig. 1), four more species of Melanoplus are found: luridus, iinpudicus, fasciatus, and scud- deri. In comparison with the four open-ground species previ- ously discussed, these four sheltered species confirm the gen- eral deductions, as they all invariably had red hind tibiae. This is true of these species elsewhere, excepting fasriafn.s, of which individuals with pale green tibise have been recorded. In the above comparisons of species from open ground I refer to the colors of local examples from the sand regions only, and an examination of records of the same species for the hu- mid prairie and the sand region of the foot of Lake Michigan, 216 with its moister atmosphere, at the eastward, and for the more arid western regions, will be of interest. Femur-ruhrmi and atlanis are common on the humid prai- rie of Illinois. The tibiae of the former are always red there, as in the sand region; those of the latter, as shown by a large number of specimens, are about ninety percent red—the rest being green—instead of only two thirds red as in the sand re- gion. Blatchley ('03) says of angustijpennis in the Lake Mich- igan sand region, that at least one third had red tibiae, the rest blue. In a series of 64 specimens, 33 males and 31 females, taken by me near Waukegan, exactly one half have red tibiae. This is very significant, since red tibiae were seen in only two out of 125 of the same species in our western Illinois sand re- gions. The tibiae of minor, according to Blatchley, are usually pale blue, pinkish at tip, sometimes red or dull yellow. Of these four species in regions to the westward I have found the following records. McNeill ('99) found one female fenmr-ruhmni in October in southwest Arkansas with green hind tibiae. In Texas I have recorded ('06) two such occur- rences among only a few specimens seen in the early part of the winter. Scudder ( '97 ) says the hind tibiae are normally red, occasionally more or less tinged with yellowish, very rarely pale green with a yellowish tinge. Examples with greenish tibiae are recorded by him from the alpine region of the White Mountains, and from Massachusetts, Utah, Texas, and Mexico. The Massachusetts localities appear to be sandy districts. Gil- lette ('04) notes that the uniform fuscous-brown of this species in the East becomes in Colorado variably yellow-brown or with bluish tints, in the latter case the tibiae also often bluish. As to atlanis, Scudder ('97) says the tibiae are normally rather bright red, not infrequently pale red, green, or yellow, or even dark blue. According to him, examples from the arid West are decidedly paler and more ashy, also those from sandy localities such as the seashore. He records green tibiae in New Hampshire and Massachusetts at the East, and in Montana, Wyoming, Dakota, Colorado, Nebraska, and Missouri at the West; also blue tibiae in Iowa, Colorado, Utah, and Texas; but ai7 thinks the red are always in the majority. McNeill ('99) re- cords from Arkansas 39 athnus with red tibiae and 42 with green. Caudell ('03) found the tibi?e of this species in Colorado to be bright red, yellow, or blue. Cockerell ( '89) calls the blue-legged form cwrule i pes. Scudder says the hind tibia? of minor are generally nearly uniform in color, usually pale red or glaucous, sometiuies plum- beous or yellowish. Dodge (78) noted "a red-legged variety" in Nebraska, of which he had taken many, but, as in our col- lections, all were females. As in the previous comparison con- cerning this species, the evidence is not full enough to be of value here. Scudder ('97) records only six specimens of (dif/usfijiejuiis. all from Montana and Nebraska, describing the hind tibiae as glaucous, feebly lutescent apically; })ut he has described M- coccineipes, with bright red hind tibiae, from 59 specimens from Utah, Colorado, Nebraska, and Kansas, which is now generally regarded as merely the red-legged form of (lugusfipexuis. If such it be, then the usual rule seems reversed in this case, and it may possibly be that, after all, the two are not the same spe- cies. Cxillette ('04) records for Colorado a single male of ^^y/- (///6f/^je/y>y/6- and moderate numbers of coccineipes, but remarks on the probable specific identity of the two. The only record of variation in jiavidiis which I have seen, is that of a single otherwise abnormal, doubtful example from Colorado with pale red tibi* (Scudder, '97). Mehnioplus packdrdii, a very variable species of wide range west of the Mississippi, has the tibiae either glaucous or uniform red, according to Scudder ('97). He had 176 specimens. These showed that in this species red tibia^ prevail, perhaps ex- clusively, at the northward, occurring from British Columbia to Montana, and thence to New Mexico and Kansas. Both red and blue tibiae are seen in examples from Montana, Utah, Col- orado, and Nebraska, and blue only in the specimens from Wy- oming, Iowa, and Texas. Bruner ('85) received quite a num- ber of examples of packardil from Oregon and vicinity, all of which had the hind tibiae red, instead of bluish—the usual color 218 in Nebraska specimens. Gillette states ('04) that the species occurs both on hills and on level ground in Colorado, and of his specimens 69 had red and 58 blue tibiae. McNeill ('99) found the tibiae green in southwest Arkansas, red and green in Newton Co., and purplish red in Marion Co. The records of this species indicate that the cooler northern climate has the same effect as a humid climate in favoring the development of red tibiae. The Rocky Mountain locust, M. spretus, has red tibiae, and its normal range is from the Saskatchewan towards Colorado and Utah. Examples with pale blue tibiae {M. spretus cwrideipes Ckll.) are recorded from Nebraska by Dodge ('78). Finally, Scudder has separated M. bivittatus, having yellow tibiae, from femoratus, having red tibiae, but these are almost certainly varieties of one species. Femoratus ranges from Nova Scotia and Maine to British Columbia and California, and south to Colorado, Nebraska, Missouri, Illinois, Indiana, Maryland? and North Carolina. It is much the commoner of the two in Illinois, all but 4 out of 133 taken by us in this state being of this variety. Bivittatus abounds on the Great Plains, ranging principally from Texas to Utah and Nebraska and, in lesser numbers, from Texas to Ohio, and northward into Canada be- tween Manitoba and the Pacific. The range of these two spe- cies accords with that of the two tibial color-varieties of species previously mentioned, indicating that variation in tibial color, which is the only constant difference noted between bivittatus 2i,nd femoratus, is not a sufficient basis for specific separation. Briefly, then, some species of Melanoplus have bluish tibiae only, some red only, regardless of locality, but in other species we find individuals with both kinds of tibial coloration in vary- ing proportions, red on the one hand, and various combina- tions of blue, green, and yellow on the other, the proportion of the two differing greatly according to species and also accord- ing to locality, in all species but possibly one the blue tibiae increasing with the increase in aridity or in sandiness, except in higher latitudes, and being most numerous east of the Rocky Mountains, from Texas to Nebraska, and least so east of the Mississippi and towards the extreme north. 219 The details previously given are collated in the following table, in which the figures, when standing alone, represent per- centages of individuals of the variety with bluish to yellowish tibice, instead of red. Estimated percentages are queried, and dashes indicate lack of data or non-occurrence of species. In the absence of precise data the proportion is expressed by words, or, if unknown, is indicated by the plus mark (+ ). DISTRIBUTION AND PEOPORTION OF MEL.VNOPLUS HAVING BLUISH TO YELLOWISH HIND TIBhM. Species 220 the change seems to be, as in the spectrum, from red to yellow, then green, then blue, the intermediate steps between red and green or red and blue being usually absent. Local Disteibution of Species in the Sand Areas. The Insect Associations. A careful study of the life of a region soon enables one to separate it into biological groups or associations, although in the ultimate analysis nearly every species requires a shelf of its own in the biological classification. It does not seem desir- able in this connection to attempt more than a sketch of the insect life of each of the various general types of environment in the sand region. The observations here recorded are given also in the annotated list which follows. One would not at first sight expect to see much life on the areas of bare sand or with very scanty vegetation, (PL X., XIII.-XVI.,) but, in fact, all except the larger entirely barren areas are busy scenes of insect activity, and there seems to be no great change in relative numbers from year to year. The exposed species of the blow-sand may receive attention first. These are largely predaceous. Cicindela formosa generosa and G. scutellaris lecontei are common everywhere (PI. XIV., Fig. 1; XV., XVI.), and the light-colored and wary C. lepida flits on the bare sand in blowouts (PI. XIV., Fig. 1, 2). The vertical burrows of their larvae may be seen opening here and there, and the beetles themselves may be dug out of such burrows in wet weather. Stachyocnemis apkalis likes to run over the sand among thin vegetation (PI. XVI.), and is sometimes seen in ex- cessive abundance. Returning to a locality where it had been thus abundant the day before, rainy weather having set in meanwhile, I could find only one or two anywhere in the vicinity where they had just before been most numerous, and these were hiding under dried horse-dung. Some were once noted apparently feeding on a bit of fresh bird-dropping. Lep- idoptera are not much in evidence here, except Euhaphe and Cramhus haytiellus, which are not infrequent. In the blowouts (PI. XIV., ¥[g.l)Microbembex monodotita 3ind Laphystia 6-fasciata 221 are seen resting on the bare sand and occasionally making a short quick flight. Bemhex spinoke is occasional. The Bemhe- cidce oviposit in burrows in the sand and provision them with flies. The red female Mitfi/l/(hv are conspicuous as they walk hurriedly along, presumably in search of insects with which to stock their nests, often followed by the black, winged males. (PL XIV., Fig. 1; XV., XVI. ) Predaceous flies. Anthrax and Asilidce, the latter including Lcqjhi/stid, are common, rest- ing on the sand or flying about. (PI. XIV., Fig. 2; XVI.) Those alert personifications of incessant activity, the Ceropalidce, flit rapidly along near the ground amongst the vegetation, (PI. XVI.,) searching for spiders for their nests, and if the spider Phidippiis insolens did not look so much like a female mutillid it might not be able to assume the manner which gives it its specific name. Of course the grasshoppers are a conspicu- ous feature of the blow-sand, MelcDioplns fiavidus and M. angus- tipeiuiis and the bright-winged (J^dijwdinfr—such as Spharage- niOH iryonii)igianiiiu,Hippiscus, Pshtldia fenestndis, and others — jumping about or flying here and there over the bare sand. (PI- XIV., Fig. 1; XV., etc.) Logs, boards, dried dung, and other shelters are not very common on the sand prairie, but underneath them we find a second and very interesting group of insect associations. At the Devil's Neck we have found Grglliis personatus, Nothopus zabroides, CeuthopldUis sp., GeopliiHS incrassatus, Cnffacfuiflius diibius, Harpalifs caliginosus, Anlsodxictylus nisticiis, Tcnties flav- Ipes, and others, the Carahidw all quite abundant. In June many Nothopus were found here, but all were dead. Under bark and sticks on sand under trees (PI. XX., Fig. 2) were Ischnoptera huequalis, UdeopsylJa robusta, and some curious cydnid nymphs. Beneath boards on very sandy pasture land were Lacon yedangiilmi and Opatr'uius iiotifs in abundance, also Harpalns testaceus and H. erraticus, the latter commonest. Un- der the remnants of a dead animal in a blowout were Trox sca- hrosus and Canthon nigvicontis. A third group are the burrowers in bare sand, among which are the tiger-beetles and their larvae and various Hgmenojjtera. 222 The ant-lions made their obconic pits wherever they could se- cure protection from rain, and waited at the bottom for an unwary insect to walk into the trap. A tiny surface-burrow in open sand, like that of a mole, was made by a small carabid larva. The most curious work seen, was that of a small active microlepidopterous larva, which webs together a tube of sand, usually beginning at the base of a plant, and extending it long distances (two or three feet), up to the tops of the stems. We have found these web tubes on Onagra and several other herba- ceous plants. The adult was reared by Mr. J. J. Davis, and named by the Bureau of Entomology Olefhreides cUniidiana. Discrep- ancies in the biology of that species and ours lead us to think that an error has crept in somewhere. The web closely re- sembles that of Prionapferyx nebidifera, described and figured by Daecke ('05), which he found on huckleberry and sand myr- tle growing on white sand in New Jersey; but Mr. Daecke has seen our larva, and says it is not the same as his. Turning now to the tufted and moderately dense vegetation of the neighboring areas of open waste land, too sandy for cul- tivation or even for pasturage (PI. XVIII., Fig. 1), there is found an apparently inexhaustible variety of insect life. Grass- hoppers swarm everywhere here. Melanoplvs augustipennls is as numerous here as M. femur-riibrurn on the prairie pastures. Ageneottetlx scudderi, Psinidia, and Trachyrhachis, as well as the more familiar Dissosteira 2,n& Hipinscus rugosus, are seen in fall, and Hippiscus phcenicopterm and H. haldemanil in June. About the Devil's Neck, Amphitornus bicolor, a species of the Great Plains, was now and then taken in such ground. In short growths of coarse grass at the Moline Sand Hill were large numbers of Orphulella speciosa. Upon the vegetation of the waste areas mentioned were (Ecanthus 4-punctatus, Bacunculus hlatchleyi, and Conocephalus rohustus,—the latter, head down, simulating a grass leaf,— also Campylacanfha, Neottiglossa sulci- frons, and a host of others. The Campylacantha was not con- fined here to Ambrosia bidentata, upon which we uniformly found it in southern Illinois. Here ant-lion adults fluttered 223 weakly about. The song of Cicada niarrjhmfa, resembling that of the periodical cicada, was heard; and in the twilight came the penetrating shrilling of Conocephalas robustus, and the rat- tling note of the male of Heliocheilus paradoxus, as moths of the latter species danced in groups here and there. The abundant wild flowers were visited by large numbers of bees, wasps, and other aculeate Hijmenoptera , many of which were species rarely or never seen on the prairie, — Diffis plu- nn'jje.s, for example,—probably associated with the unusual flora. Fauiilies which nest in sand were well represented, such as the Larridce, which capture young Orthoptera to provision their nests, the Bewbecida', which use flies for this purpose, and the bee family Collefidrf'. In fact, this kind of region seems partic- ularly favorable to the development of these insects in great numbers and variety because of the undisturbed ground and vegetation in addition to the character of the soil. Hoppner COl) shows that similar conditions prevail in a tract of dune sands along the Weser valley in Germany, fiading there six characteristic local species of bees, and three others more abundant there than elsewhere, the total list including two thirds of all the bees found in northwest Germany. To de- velop this subject for our district would require vastly more time than was available. The insects associated with some of the more common plants of the sand region may next be grouped under their re- spective plants. Mesadenla atr/plieifolia.—This may well head the list of host plants, with its interesting insect guests. On the flowers of scattered clumps of these plants were two far western spe- cies, a large tenebrionid (Eplfraf/Ns artffa.s) and a long-legged re- duviid {Zeliis sociiis), also Lijga'us bicrucis, and, upon the stems, Languria bicolor, the larvae of which burrow in the stems. Opuntia humifusa.—This cactus was usually abundant, and sometimes supported flourishing colonies of Pentatoma Janipjeri- na. It was also responsible for the presence of the bright-yel- low-striped chunky little syrphid fly, Volucella fasciata, seen 224 feeding in the flowers of various plants, as its larva lives in the cactus flesh. Collops tricolor, Acmceodera tuhulu?^, and Strigoder- ma arhoricola were noted within the flowers. Onagra biennis.—In addition to the larva of the web tube previously mentioned, this was fed upon by Attelahus hipustu- latiis, Haltica fuscocenea, Tyloderma foveolatnm, and Ckalcoder- nius coUaris, and often harbored a number of adult Metachroma parallelum. Monarda punctata.—This abundant plant of the sand re- gions about Havana was seen at different times to have its stems dotted with Corimekena ciliata and Sehirus cinctus. The Coriniekena, usually considered quite a rare species, was also extremely abundant in nearly bare sand about the bases of lit- tle grass tufts, every turn of the finger in the sand bringing several to the surface. Honey-bees were common upon the flowers of the Monarda. Commelina virginica.—The leaves of this plant were white- streaked by the feeding of adults of Lema corntda, the larva of which bores in the stems. Rhus aromatica.—This dense, bushy sumac (PL XIX.) sup- ported BJepharida rhois and its sticky larvse, Perilhis circum- cinctus, and Besthenia insitiva. Catorhintha niendica and Zelus socius also occurred on it. Euphorbia coroJlata.— Chariesterus antennator was once noted very common on flowers of this species. Cassia chfonwcrista.—This common flowering plant of the waste sand land was well populated. Bonibus, Apis, Plesia (Mgzine), Polistes, eta., were busy on its flowers, and PAormiw temenovcF was numerous about it. Bruchus cruentatus was swept from it in numbers, probably breeding in the seeds. Cracca virginiana.—A group of these plants was infested with Macrobasis unicolor. Callirhoe triangnlata.—This formed a sprangling tuft of stems and long-petioled radical leaves, and at their extreme bases, within the tuft, were often large enveloping masses of "frog-spittle", containing bulky blackish larval Cercopidce, proh- 225 ably Le})yrou}(( mydida. the adult of which was taken on this plant. Euthamid sp. (Solirla(/o).—In a small patch of this plant the ph^'tophilous Hesperotettix prafensis was quite abundant. Along the railroad track near Forest City, Phaeepholis Can- dida was abundant on some undetermined low weeds. For the concluding group of inhabitants of the open waste sandy land I may appropriately mention our herpetological ob- servations in this region, which cover all the characteristic ver- tebrates noted. There were four of these: the box-turtle {Cis- tiido Carolina, PI. XI[.,Fig. 2), the striped \iz3,Yd{Cnemido2)honis scxiineafas), the hog-nose snake i Ht^ferodoh simas), and a small Hy/a, or tree-toad. Ten years ago the box-turtles were quite common at the Devil's Hole, but I have seen very few of late years. The striped lizard ranges throughout the valley, and is not rare here. The hog-nose is quite common, especially along roadsides and sandy shores. The general arid aspect of the sandy regions is relieved by the moist growth at the bottoms of deep wind-excavations in the sand, and here a very different fauna obtains. Adults of aquatic neuropteroids, such as Hexagenia and various dragon- flies, rest on plants here or fly about; Locustidce and their nymphs suddenly come into prominence,—forexample, A7y)///V//^/;>/, Scnd- deria, and Aitibli/rori/pJia ah/cri; and moisture-loving grasshop- pers, such as Dicliroiiiorpha riridis and Oip/i it IcJ /(f pelidna ,Ye'plsice those of the dry sand. A variety of rare and interesting Hcni- ipfcra occurred on this vegetation; for example, Honia^mus ftitei- frons. Long grass on the sides of hollows of this kind was well populated with elongate tryxaline grasshoppers, Mermiria hi- rittafa and tieomcxicaua and Sjirhiila ndniirahilis, the latter in the drier and sparser portions. The sandy roadwa5^s have some fairly deflnite insect asso- ciations. Here Aphodiu.s riiheoliis, Cantlion kevis, Ojithophagus hecafc, and 0. pennsi/Irauicas are found at the usual occupations of these genera; Anthrax, Erax, and Cicin(/cla fonno.sa generosa and sciitellaris lecontei fly along the bare wheel-track lines; Am- inophila is common, and Mttgacliih latinianas and Epeolus lunatus 226 bunch up in cool or rainy weather on the dead weed stems; while the border of dandelions and sweet clover is visited by numbers of VoluceJla fasciatus, Dielis phmupes, Agapostemo7i splendens, etc. In the level and least sandy roads are found Me- lanoplus femur-ruhrum and Cicindela punctulata, and, under boards, along the fence lines, Gryllus yennsylvanieas, Carahus sylvosus, etc. Culture of various kinds accounts for the presence here of the potato-beetle, box-elder bug, chinch-bug, potato stalk-borer, and house-fly, and of the male of Blatfa orientalis at an electric light. In a street at Forest City, adults of Lucanus phicidiis were coming to the surface at the base of shade trees along the walks. Taking up now the forested ground, a situation claiming especial attention is the very sandy black-jack land, with its matted scrubby growth (PL XXL, Fig. 1), whose contribution to our list of sand insects was by no means small. The char- acteristic grasshoppers here were Melanopjlus luridus, impudicus, scudderi, Siud fasciatus, and Chloealtis cmispersa. Along the roads were Hlpplscus phles of male rounded, ecarinate; of female strongly carinate on the inner side of the dorsal surface—especially over the subapical tooth—and usually a lower carina along its outer margin; top of head of female anteriorly ru- gosely punctate and very opaque; elytra and thorax shining, dama Thunb. Mandibles of both sexes subtriangular in cross-section, their dorsal surface • concave, with a strong carina along its outer margin only; the inner edge sharp, bidentate in the female and multidentate in the male; entire dorsal surface of insect with dull luster. placiduti Say. Note 16, p. 248. — Pharepholis candlda. Dr. Horn described this from two specimens as "nearly white." It has, in fact, a color pattern similar to that of ohscura^ in pale brown and white. The thorax has a dorsal darker stripe divided by a fine median white line, and lateral and ventro-lateral darker stripes. The elytral scaling is very pale golden-brown, with two vague stripes and the 266 lower margins white. The scales beneath are nearly white, without evident pattern. Note 17, p. 251. — Laphystia 6-fasciata.—Dr. Williston says (Trans. Am. Ent. Soc, Vol. 12, p. 53) : "Specimens of this sijecies from Montana differ appreciably from those from the Southern States that I have seen. In all the northern specimens the pol- linose bands of the abdomen are all entire, while in the southern ones they are mostly interrupted ; the femora, moreover, in the former are mostly yellow, while in the others they are chiefly black. These differences, if not sufiicient to warrant specific separation, may be varietally indicated by the name notata Bigot for the south- ern form. " In our specimens the femora are reddish and the fifth abdominal band is clearly interrupted. Note 18, p. 254. — SphcBrophthalma Ghlainydata. Melander ('03) collected "several" specimens of a male mutillid in the sand region about Bath (designated in this list as H.3) which he determined as hioculata^ and of a female, described by him as new under the name chlamydata. Ten of my 16 unassigned males are his hioculata^ and 61 of the 83 unassigned females are his cJilamydata. On one occasion one of these males was seen dancing in attendance upon a female cMamydata^ both being then captured. Their occurrence is coin- cident, and they have close similarities in vestiture. It would seem proper to accept them as two sexes of one species. However, hiocu- lata in the West has been connected by Cresson with quite a differ- ent female, which Fox conjectures may be the same as creusa Cres- son. Since the females are more reliably separable than the males, it would seem best for the present to retain the name chlamydata for both sexes in our region. Note 19, p. 254. — SpJimrophthalma macra. The single example which is assigned to this species has an evident coarse orange pubes- cence on the second segment, the dorsal reddish area of which does not seem to be two partly confluent spots as is the case in the more common types assigned to ferrugata and ^<7en<9r, in which also the pubescence is yellowish and not evident when viewed vertically from above. Note 20, p. 2bb. —AmmopMla argentata^ n. sp. The sides of the thorax are covered with a mat of uniform silvery pubescence, its dorsum is less conspicuously silvery pubescent; the face is silvery, the red or yellowish of the abdomen extends from near the base of the second joint to beyond the middle of the fourth, or even upon 267 the base of the fifth ; the legs are wholly black ; the thorax is rather sparsely punctate ; the nietanotum is finely and densely obliquely striate; the wings are yellowish hyaline. Length, 18-21 mm. One male, three females. Mason Co., 111. Type in coll. 111. State Lab. Nat. Hist. Note 21, p. 256. — Bemhldula capnoptera. The single example agrees with the description of this species except that the abdom- inal yellow bands are of good width, about equal to the intervals between them, and all rather narrowly interrupted at middle. BIBLIOGRAPHY, Ball, E. D. '97. Notes on the Orthopteirous Fauna of Iowa. Proc. Iowa Acad. Sci. (1896), Vol. IV., p. 234. '01. The Food Habits of some Aphrophora Larvae. 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Bull. N. Y. State Mus., No. 97 (20th Rep. N. Y. State Ent.), p. 546. Vosseler, J. '02. Beitrage zur Faunistik und Biologie der Orthopteren Al- geriens und Tunasiens. Zool. Jahrb., Abhandl. f. Syst., Bd. 16, pp. 337-404, PL 17, 18, 8 fig. in text; Bd. 17, pp. 1-98, PL 1-3, 5 fig. in text. Warming, E. '96. Lehrbuch der okologischen Pflanzengeographie. Deutsche Ausgabe von Knoblauch. Whitney, M. '98. Some Interesting Soil Problems. Yearbook, U. S Dept. Agr., 1897, pp. 429-440. Whitney, M., and Cameron, F. K. '03. The Chemistry of the Soil as related to Crop Production. U. S. Dept. Agr., Bureau of Soils, Bull. 22. Whitney, M., and Hosmer, R. S. '97. Soil Moisture : a Record of the Amount of Water con- tained in Soils during the Crop Season of 1896. U. S. Dept. Agr., Division of Soils, Bull. 9. Williston, S. W. '91. [Note on the Rearing of Copestylum marginatum and . Volucella fasciata from Opuntia missouriensis.] Ent. News, Vol. II., p. 162. Wolcott, A. B. '95-'00. Coleoptera of Central Illinois. Ent. News, Vol. VI., pp. 309-310; VII., pp. 234-238; XL, pp. 468-470 VIII. TX. X. XI. XII. Fig. 1. Blow-sand entirely without vegetation. A grove of walnuts (Juglans nigra) in the rear. Fig. 2. Traveling dune formed of sand removed from a blijwout. A small thicket of plum-trees has been partially buried and the trees killed. A dense zone of Diodia teres grows around the edge. Rohinia pseudacacia cultivated in the background.—The zigzag line at the edge of the sand is the track of a box-turtle {Cistudo Carolina). XIII, XIV. Fig. 1. Large blowout, the slopes still hare, but with the typical blowout association on the flat bottom. The low vertical walls of sand are held in place by sand-bindiuK grasses.—Most abunilant on the bare sand are Microbemhiex, Laphystia, Cuimlela /epiila, and Melan- oijlus Jiitvhliis: and m the sparse growth various J/"«//V//(/(f, Meliinoplwi i(/i.'justipen>ii-s, AfjeiicDleUix scudderi, Sphararjemoii iDj/iiiiiinijiiinnm, Atuhrax, ChiiKtelaformosafjenerosa, and G. sculelktriti lecoiUei. Fu;. 2. The .steep wall of saiiil is held in place by I he l)unch-grasscs at its top. They are being gradually undermined, as shown by the sliding plants on the slope.— .\ favorite place for Ck-iiuk'la, Microbembex, iUutillidte, antl Melttnoplus Jlavidim . XV. XVI. XVII. ^-^ n 2 XVIII. Fig. 1. Bunch-grass association (Stipa sparlea) on top of a hill, showing the open character of the vegetation. The trees in the background are not native. — Mdanoplus anflnstipe7i7iis, Ageneotettix scudderi, Mestobregma thotnaai, Hippisciis rugosus, and Mu- tillidcK are common, and in early summer Hippiscu/i phoeni- copterus and //. haldemanii. Conocephalus robustus also occurs here. Fig. 2. A single plant of Sporobolus cryptandrus growing on blow-sand has built up a conspicuous mound beneath it. XIX. Fig 1 . A low mouiiil of saiiil held in place by Rhm Ufomaticu. Several other species grow in the pro- tected sand on its lee side. The small plants in the left foreground are Commelina virginica. Fig. 2. A dense thicket of the saiid-l)iiider Uhitu aruiiMllca. The I uniMoweeds, Cuclulomu (UriplkifoUin are the only plants on the blow-sand in front.— Upon the HhuH are Hkpharida rliois and its larvae, Pelil/ii.'i rircunicinctzis and its nymphs, Iitatlnnki iimitiva, and the predaceous XelTtssocUis. XX. Fig. 1. Pojmlus Dilatata spreading by suckers over the blow sand into the blowout. Jamesii grows in abundance in the right foreground.—Upon the Populiis are Metachroma parallelum and M anguslulum. Cristatella 1 ll/l 1 XXI Fio. 1. Interior of a black-jaok forest.—On the ground are Melanoptus fanciatus, M. luridua, and M. impudicus, and under gatherings of dry leaves Gryllua is abundant. Along the forest margins are Schisiocerca alutacea and Hippiscus phaenicopterus. XXII. ^1 a p o " n cr •^ c o P o £. XXIII.