UMASS/AMHERST 3120bbD05375n5 hi;!* faf.: LIBRARY OF THE MASSACHUSETTS AGRICULTURAL COLLEGE SOURCE.. Q^ 496 — — v,l v.l DATE DUE CARO University of the State of New York New York State Museum Frederick J. H. Merrill Director^ TT*T? A T^'NT'- ♦" HARS11913 Bulletin 47 September 1901 AQUATIC INSECTS IN THE ADIRON A study conducted at the Entomologic field station, Saranac Inn N. Y. under the direction of Ephraim Porter Felt D.Sc. State entomologist- JAMES G. NEEDHAM Ph.D. Professor of biology, Lake Forest university, AND CORNELIUS BETTEN M.A. Assistajit PAGE Preface 383 Part I Introductory: the undertak- ing, location, objects, methods and results 384 Part 2 Life of Little Clear creek 400 Part 3 Insect life histories 410 Plecoptera 412 Ephemerida 418 Odonata...... 429 Neuroptera 540 Trichoptera, by Cornelius Bet- ten 561 Part 3 Insect life histories (iT^K^V) page Diptera 573 Notes on other orders 582 List and two new species of saw- flies, by A. D. Macgillivray 584 Original descriptions of new Dip- tera, by D. W, COQUILLETT 585 Descriptions of five new parasitic Hymenoptera, by W. H. AsH- MEAD 586 Explanation of plates 590 List of text illustrations 597 Index 599 ALBANY UNIVERSITY OF THE STATE OF NEW YORK I901 M77m-Do-3ooo Price 45 cents University of the State of New York REGENTS With years of election 1874 Anson Judd Upson L.H.D. D.D. LL.D. Chancellor^ Glens Falls 1892 William Croswell Doane D.D. LL.D. Vice- Chancellor, Albany 1873 Martin I. Townsend M.A. LL.D. - - Troy 1877 Chauncey M. Depew LL.D. _ _ _ _ New York 1877 Charles E. Fitch LL.B. M.A. L.H.D. - Rochester 1877 Orris H. Warren D.D. - - - - - Syracuse 1878 Whitelaw Reid M.A. LL.D. - - _ New York 1881 William H. Watson M.A. M.D. _ _ _ Utica 1881 Henry E. Turner - - - - - Lowville 1883 St Clair McKelway M.A. L.H.D. LL.D. D.C.L. Brooklyn 1885 Daniel Beach Ph.D. LL.D. - _ _ _ Watkins 1888 Carroll E. Smith LL.D. _ _ _ _ Syracuse 1890 Pliny T. Sexton LL.D. _ _ _ ^ - Palmyra 1890 T. Guilford Smith M.A. C.E. LL.D. - - Buffalo 1893 Lewis A. Stimson B.A. LL.D. M.D. - New York 1895 Albert Vander Veer Ph.D. M.D. - . - Albany 1895 Charles R. Skinner M.A. LL.D. Superintendent of Public Instruction, ex officio 1897 Chester S. Lord M.A. LL.D. _ _ _ - Brooklyn 1897 Timothy L. Woodruff M.A. Lieutenant-Governor, ex officio 1899 John T. McDonough LL.B. LL.D. Secretary of State, ex officio 1900 Thomas A. Hendrick M.A. LL.D. _ _ - Rochester 1901 Benjamin B. Odell jr LL.D. Governor, ex officio 1901 Robert C. Pruyn M.A. - - - - - Albany secretary Elected by regents 1900 James Russell Parsons jr M.A. directors of departments 1888 Melvil Dewey M.A. State library and Home education- 1890 James Russell Parsons jr M.A. Administrative, College and High school dep''ts 1890 Frederick J. H. Merrill Ph.D. State tnuseum University of the State of New York New York State Museum Bulletin 47 September 1901 AQUATIC INSECTS IN THE ADIRONDACKS PREFACE The following account presents in part the results obtained by a close study of aquatic insects in one locality. Saranac Inn proved an excep- tionally favorable place for investigations of this character, and the labor of two earnest, enthusiastic workers made the entomologic field station a very successful institution. Only 10 weeks in the field sufficed for work- ing out in more or less detail the life histories of about 100 species, the discovery of 10 new species and two new genera, and for material additions to the list of insects known to occur in the state. The bred Chironomidae, the material representing the suborder Zygoptera of the dragon flies and the collection of fish stomachs, which have not been included in this report, should give, when worked up next year, a large number of additional interesting and valuable facts. This work, even when all available data are brought together, does not complete the desirable investigations along this line. Dr Needham's report, though thorough so far as it goes, is largely of a preliminary nature and will prove an excellent basis for subsequent work. It is physically impossible to do more than this with 10 weeks in the field. The solving of the complex interrelations existing between the various aquatic forms requires persistent efforts extending through a number of seasons, and the results thus obtained should be verified by studies in other localities. This is a large field requiring the serious attention of the botanist and zoologist, using these terms in the general ^ense, and the practical value of these studies can not be fully available till such an investigation is made along broad and comprehensive lines. A study of this character could be conducted at a comparatively small outlay, and would prove of great benefit to fish culture, and should result in the rear- ing of many more fish in the fresh waters of New York state. E. P. Felt State efitomologist 39728 384 NEW YORK STATE MUSEUM Part I INTRODUCTORY THE UNDERTAKING, LOCATION, OBJECTS, METHODS AND RESULTS " To collect and study the habits of aquatic insects, paying special attention to the conditions necessary for the existence of the various species, their relative value as food for fishes, the relations of the forms to each other, and their life histories" : such were the instructions under which I went to Saranac Inn, to take charge of the opening session of the entomologic field station. Arrangements had been previously made with state entomologist Dr E. P. Felt, that the session should extend from June 15 to August 20. I arrived at Saranac Inn on the evening of June 12, and at once began looking the ground over. Dr Felt came on the 14th, and spent the day with me canvassing the situations to be studied. My assistant, Cornelius Betten, arrived on the 15th, and the regular work of the session was at once begun, to be continued without cessation to the date of closing. Through the courtesy of the New York state fisheries, game and forest commission the station was furnished with working quarters in the hatch- ery building, and was allowed the use of parts of the hatchery equipment, not then otherwise needed. There were three very considerable advan- tages to our work in this arrangement : i) the use of several hatching troughs with their continuous supply of well aerated water for insect breedings, 2) the use of a carpenter's bench and tools for the construc- tion of special breeding cages, 3) the use of a boat for collecting. We were soon supplied with a special equipment for the collecting and rearing of aquatic insects, that was excellently adapted to our needs, and without which the work hereinafter recorded could not have been done. Our sincere thanks are due Dr Felt for his care in providing exactly the apparatus asked for. Save for the first 10 days, during which we were unable to find living quarters within 2 miles of our field of operations, we had the still farther great advantage of close proximity to good collect- ing grounds. The season was one of excessive rainfall. The first week of the session and the last one were comparatively dry; but, for the remainder, it was raining more than a third of the time. Thus collecting was greatly inter- fered with, sweeping of vegetation was almost prevented, trap lanterns were flooded night after night and their catch spoiled, and regularity in field operations was made impracticable. The routine work of the station consisted in collecting and studying aquatic insects in all their stages of development, in conducting feeding AQUATIC INSECTS IN THE ADIRONDACKS 385 experiments, in making quantitative studies of the life of certain situations, in gathering the materials for the study of the natural and habitual food of trout, bullfrogs, and some of the larger species of dragon flies, in run- ning trap lanterns and sending their nightly catch to the state museum, etc. Besides three official visits made by Dr Felt during the course of our session, our station was visited for a week or more at a time by three scientific friends, who, while there, participated in our operations, and, while collecting for themselves, gathered also valuable materials and information for us. These were Louis W. Swett of Maiden Mass., H. N. Howland of Austin 111., and Dr O. S, Westcott of Chicago, It is a pleasure to acknowledge the assistance gratuitously rendered by these gentlemen. Biologic features of the locality As is well known, the Adirondack region of northeastern New York is an extensive area of forest, having an average elevation of about 1800 feet. Its eastern half is covered with a succession of low mountain ranges, whose general n n e-s s w trend is indicated on the accompanying map (map i) by the trend of the streams which occupy the narrow valleys between them. The western half is a region of lakes and swamps and bogs, with scattered mountains and hills and ridges. Map I shows the principal streams that participate in the drainage of the Adirondack region, the principal lakes, and some of the mountains. It will be observed that the lake region of the Adirondacks is drained principally through Racket river into the St Lawrence. Saranac river is the only one on the Champlain side that drains any considerable part of the lake country. Our station at Saranac Inn was at the head of the Saranac drainage system. Map 2 shows the immediate field of our operations. As stated above, the hatchery was our working headquarters. We did more collecting from Little Clear creek right on the hatchery grounds than from any other equal water area, and obtained more material of value there than in all other places combined. More or less regular collecting was done, however, from the three propagating ponds. Little Clear, Little Green and Bone, and from Little Bog pond, southwest of the railroad station. Two collecting trips were made to each of the following places : Colby pond, at the western outskirts of the village of Saranac Lake; Stony brook, just north of Axtonj and St Regis pond, at the end of the carry from Little Clear, The mornings and evenings of the first week of the session were spent gathering material about the south shore of Lake Clear, or Big Clear at Otisville. 386 NEW YORK STATE MUSEUM Map 1 Drainage map of tlie Saranac region Lakes: 1 Raquette ; 2 Long ; 3 Tupper ; 4 Ne-ha-sa-ne ; 5 Cranberry; 6 Upper Saranac ; 7 St Regis ; S Rain ^°:?^i<;L™MUl^eT&s'aranac Junction; c Saranac Lake ; d Lake Placid : e Saranac Inn ; /Tupper Lake ^ muntains /^rnVhiteface ; n Marcy (Tahawus) ; o Seward ; p Boot Bay ; q St Regis AQUATIC INSECTS IN THE ADIRONDACKS 387 Saranac Inn is very near the Champlain- Ontario divide, on a sandy, undulating mountain upland in the midst of almost unbroken forest. Round about it are numerous lakes, ponds, bogs and clear, slow flowing streams, with here and there a low ridge built on outcropping gneiss, or a sharply rising, densely wooded hill. There is more of sand and less of rock, more of water area and less of mountain, than in most places in the Adirondacks; and the descent of the streams is much more gentle. The forests are composed, as elsewhere, mainly of hemlock and balsam, beech, yellow birch and maple, pine and spruce having been mainly removed by lumbering, and oaks and our cemmon nut-bearing trees never having been present in the Adirondack woods. In the drier and denser parts of the woods, where there is little undergrowth, the hobblebush. Viburnum alni folium Marsh., spreads its broad leaves on strag- gling branches to catch the scanty sunlight, while Indian pipe, Monotropa uni flora Linn, star flower, Trientalis ameri- cana Pursh, rattlesnake plantain, Peramium pu bescens (Willd.) MacM., Indian cucumber root, Medeola virginiana Linn., the yellow Clintonia, C 1 i n t 0 n i a borealis Linn., the dwarf Smilacina, Vagnara tri folia (L.) Morong, several pretty species of ground pine, Lycopodium, and innumerable mushrooms spring from the loose leaf mold. Recently burned tracts are mainly in the possession of the bracken fern, Pteris aquilina Linn., the fireweed, Chamaenerion angustifolium (Linn.) Scop., poplars and wild cherry. In wet places in the woods occur stemless lady's slippers, C y p r i - pedium acaule Ait., in the shadows, and in the openings grow cin- namon fern, Osmunda cinhamomea Linn., and clumps of the red elder berry, Sambucus pubens Mx., which in midsummer, when the fruit is scarlet, are strikingly beautiful. In the bogs the trees are balsam and tamarack in nearly clear patches; the shrubs are mainly Labrador tea. Ledum groenlandicum Oeder, small cranberry^ Oxy coccus oxycoccus (Linn.) MacM., lambkill, Kalmia angustifolia Linn, and the pale laurel, Kalmia glauca Ait.; the herbs are mainly the universal sphagnum, the cotton grass, Erio- phorum sp.?, the sundew, Drosera rotundi folia Linn., the swamp five-finger, Comarum palustre L., and a variety of orchids. The more strictly aquatic plants will be mentioned in connec- tion with the situations in which they grew, and where studies were made of the insect fauna. But I should not omit to mention in passing that the exposed banks by every roadside were covered with mats of 388 NEW YORK STATE MUSEUM V - ^ ■ Map 2 Saranac Inn and immediate vicinity Lakes and ponds : 1 St Regis pond ; 2 Grass pond ; 3 Lake Clear ; 4 Little Clear pond ; 5 Little Green pond ; 1 Bone pond ; 7 Rat pond ; 8 and 9 Little Bog ponds ; 10 Upper Saranac Lake Places: a Saranac Inn railroad station ; b Adirondack hatchery ; e the sawmill ; d the Inn AQUATIC INSECTS IN THE ADIRONDACKS 389 mosses, mainly Polytrichium, and bunchberry, C o rn u s cana- densis Linn., and the latter were very pretty, when covered with white bracts, as in June, or when covered with scarlet berries, as in August. Propagating ponds. Since the three ponds reserved by the state for fish-propagating purposes were the scene of our principal field studies, a few words concerning their character may best be said here. Bone pond is quite small, as our map will show, is hidden in deep woods, and is accessible only by a " carry " from Little Green. It has gently sloping banks round about, there being no outlet, the hemlocks of the woods come down near to the shore, and there is not the usual fringe of tamaracks outside the sphagnum moss which thinly fringes its banks, but the sphagnum is grown full of lambkill and other small heaths. The sphagnum ends in shallow water and is followed by a zone of sedge, Dulichium. arundinaceum (L.) Britton, and manna grass, Panicularia sp.? In the deeper water, but not forming a continuous zone except for short distances, are stretches of yellow water lilies, Nymphaea advena Soland., and a species of bur reed with very long stem and leaves, the latter not rising from the surface, but lying flat and directed generally off shore, Sparganium simplex angusti folium (Mx.) Englm.? In the more open places along shore a species of pipewort, Eriocaulon septangulare Wither., was observed growing abundantly, and extending out into deeper water by a succession of stolons, which rooted readily to the white sand of the bottom. Among these lay loosely small masses of moss and filamentous algae. In such places the sieve net brought up from the bottom, where they were beyond view and almost beyond reach of the net, besides the pipewort, moss and algae, great quantities of empty caddis fly cases of the species described in the following account of that group by Mr Betten as no. 2, p. 572, and also the loose, flocculent cases of blood worms (larvae of gnats, Chironomidae) ; but the larvae of the gnats themselves were not found except in the stomachs of the brook trout which lived in this pond, and in these they were abundant. The burrowing nymphs of dragon flies, Gomphus, were also common here, where they burrow along under the thin layer of silt that covers the sand. They seemed to escape the trout. Among the sedges and grasses nearer shore other dragon fly nymphs and caddis fly larvae were also abundant. This pond was farther from headquarters than were any of the other situations in which we planned field studies. We did not visit it till 39P ^'EVV YORK STATE MUSEUM August, and we went to it then only because it offered an exceptionally good opportunity for the study of the insect food of the brook trout. Little Green pond is a beautiful sheet of water half a mile long and nearly as wide, with steeper banks that are nearly destitute of aquatic vegetation, excepting in the little bay on the north shore, and with a bottom of clean white sand. The vegetation of the bay is somewhat similar to that of Bone pond, with the addition of the white water lily, Castalia odorata ( Dryand.) Woodv. & Wood. Wintergreen, Gaultheria procumbens Linn., and twin flower, Linnea b o r e a 1 i s Linn., and the pretty little Dalibarda repens Linn., as well as big tufts of the lichen commonly known as " reindeer moss," occupy the dry and abruptly sloping south shore. Little Green is not a trout pond. Frequent plantings of fry have resulted in nothing. Little collecting was done there, for it seemed very barren of insect life. Little Clear pond (pi. i, 2) is nearly a mile and a half long, a mile wide, and is said to be in places more than a hundred feet deep. It is worthy of a more pretentious name. Owing to irregularities of contour, it has a very long shore line, that varies in character according to the inclination of the adjacent slopes. Conditions have been somewhat disturbed here within recent years by the building of a dam at its outlet, that has raised the water several feet, and caused it to encroach on the surrounding timber, which now stands dead along the shore. Aquatic shore vegeta- tion is not abundant except in a few places. Two places were selected in Little Clear for more or less regular collecting, the bay in Blueberry island near the west shore, and the outlet. Blueberry island is a small sandy spit of burned-over land, now covered with a thin growth of poplar trees, with broad mats of moss and lichen, with extensive clumps of blueberries, and with other clumps of Labrador tea overhanging its shores, specially in the bay. The banks are strewn with decaying trunks of fallen hemlocks, and in the narrow channel between the island and the hill to the westward dead trunks are still standing in water of considerable depth. The water is shallow for a little distance in the bay, and contains a sparing growth of aquatics, such as yellow and white water lilies, sedges, and cat-tails. Not a great many species of insects were collected from this bay, but some of these were exceedingly abundant; as, Chauliodes rastricornis., and species of Gomphus and of T e tragoneuria. The outlet of Little Clear pond offered considerable variety of situa- tion in small compass. Its east shore was strewn with logs so thickly as to be difficult of access with a boat except next the lake, where was a AQUATIC INSECTS IN THE ADIRONDACKS 391 low hummock of land covered with cat-tails. Behind this hummock was a. shallow stretch of water in which we did some most profitable collect- ing. The bottom here had once been dry land, and was covered mainly with fragments of bark and twigs, but it was the home of numerous caddis fly larvae, particularly those with cases of stick chimney, or cobhouse type, and of the nymphs of the fine May fly, Siphlurus alter- n a t u s Say. The west shore of the outlet was more accessible ; and, though collecting along it was not easy because of the abundance of brushwood to entangle a net, it yielded a great deal of most valuable material, particularly dragon fly nymphs. My only specimens of the nymphs of the two beautiful species, Cordulia shurtleffi Scudd. and Leucorhinia glacialis Hagen, were obtained along this shore in a sheltered place. Through the outlet there flows an imperceptible current, which may be responsible for the presence of two interesting plants there which were not observed elsewhere, the water shield, Brasenia peltata Pursh, and shining river weed, Potamogeton lucens Linn. Of the latter there was a bed directly in the channel, and, passing over in a boat it was delightful to look down into the depths of the clear water, at the long graceful sprays of shining lutescent leaves. A species of bladder wort, Utricularia, was not uncommon in the shallow water behind the cat-tail hummock, and two species of shinleaf grew there at the shore, Pyrola secunda Linn, and P . e 1 1 i p t i c a Nutt. Little Clear creek (pi. 7,-^) will be discussed below in connection with the account of the special studies made of the life of its waters. Bog ponds. Of the numerous small ponds in the vicinity of Saranac Inn, hidden in the woods and fringed with a typical floating border of bog moss, we collected extensively at but one — the one a quarter of a mile southwest of the station and south of the track — and visited but one other, about as far east of the station and north of the track. Of the former only I will speak here; the other was very similar. This httle pond (pi. 7) was a woodland gem. The picture of it presented herewith gives but a poor idea of it; for the fine coloration of fringing vegetation, of forest background, and of water and sky are necessarily absent from the picture. It was a peculiar place to collect in, being dif- ficult of access, and very difficult to collect in when reached ; but it was conveniently near at hand, and was peculiarly attractive on account of the many beautiful and interesting plants and insects found there Its vegetation (pi. 8) showed a beautiful zonal distribution. Farthest out 39^ NEW YORK STATE MUSEUM was the zone of the very abundant yellow water lilies. Next came a very broad zone of sphagnum, floating at its outer edge over water 5 feet or more in depth, with here and there a detached and float- ing island. This zone was fairly sprinkled over with pitcher plants, S a r- racenia purpurea Linn., and with a succession of pretty orchids, Limodorum tuberosum L., Arethusa bulbosa Linn., Habenaria sp?, while a few clumps of lambkill and tufts of cotton grass were scattered about. Back of the sphagnum was a thin fringe of pale green tamaracks, while dark hemlocks of the forest stood close be- hind, and in the pools in their shadows nestled beds of native callas. Numerous fine dragon flies and a few large caddis flies and the handsome larva of some, to me unknown, diving beetle were the principal insects observed there. Objects and results This station, being located in the midst of a region whose aquatic insect fauna had scarcely been studied at all, off"ered a wide choice of field operations. Being established solely for the study of aquatic insects, and m this respect unique among field stations, it lacked the advantage accruing from the simultaneous study of other forms of aquatic life, but offered opportunity for concentration on some of the problems of aquatic entomology. The following objects were had in mind, though it was realized from the beginning that little would be done with some of them; and that any one of them might have been made to occupy our time profitably: i) to increase the state museum collections; 2) to increase our knowledge of the aquatic insect fauna of the Adirondack region ; 3) to study the place of aquatic insects in natural societies; 4) to study the reproductive capacity of insects ; 5) to study the habits of aquatic insects ; 6) to study the food relations of insects, fishes and other aquatic animals; 7) to study the Hfe histories of aquatic insects. Additions to the state museum. Our collections of specimens were so numerous that the attempt made at first to keep some record of the number and kind of specimens was early abandoned. When hun- dreds and even thousands of specimens were being collected every day, the enumeration of them would consume time that was greatly needed for matters of more importance. Miscellaneous collections were made by sweeping vegetation with a net, and by trap lanterns set at night when the rain ceased long enough to permit these operations, and the material thus obtained v/as sent while fresh to Albany to be prepared there for the cabinet. On warm, siill, rainless nights the lanterns attracted from the surrounding v/oods a very large number and variety of moths, which have been preserved, but not studied as yet. AQUATIC INSECTS IN THE ADIRONDACKS 393 Special collections were made of aquatic insect species hitherto insuf- ficiently known, of which not a few species known only from a few poor specimens appeared at Saranac Inn in great numbers ; and we took oc- casion to gather good series of specimens of such, and also of a few new species which were no less abundant. The most valuable collections were those of life history material. All that is described in part 3 of this report as coming from Saranac Inn has been added to the state museum; and so important is this material that future monographers in several groups will find it very desirable to con- sult the collections at Albany. Aquatic insect fauna of the Adirondacks. All that has been written on this subject is comprised in a few short paragraphs in two papers by Dr Lintner,^ in a few isolated descriptions of Adirondack species, like that ofSimulium pictipes, from Ausable river^ by Dr Hagen,^ in a record b}' Dr Calvert^ of a few dragon flies collected at Lake St Regis by J. Percy Moore in 1890, and at Keesville by W. Sheraton in 1894, and in rare locality references in other lists. The Adirondacks are not less interesting entomologically than the White mountains, which have been the resort of New England entomologists for half a century. The following lists, while not even pretending an approximation to completeness (excepting, perhaps, the suborder Anisoptera of dragon flies) add a considerable number of species, not hitherto known to occur within our fauna; and also, a small number of interesting new species. Of these I have described three species and a variety under the following names: Leuctra tenella; Sisyra umbrata; Climacia dictyona; Gomphus descriptus var borealis. I have also described the male of the interesting pygmy May fly, Baetis pygmaea Hagen, hitherto known from a fragment of a single female specimen, and the female of the beautiful dragon fly, Leucorhinia glacialis Hagen (pi. 10). Mr D. W. Coquillet has described at my request two new genera and species of Diptera (see p. 585 and p. 586) ; and W. H. Ashmead has described five new species of parasitic Hymenoptera (see p. 586) and Mr A. D. MacGillivray, two new species of sawflies (see p. 585) . As the region about Saranac Inn differs considerably from most locali- ties in the Adirondacks, as stated above, its insect fauna will doubtless 1 Liatner, J. A. Collections In the Adirondack region. 5tli rep't N. Y. state entomologist, 18S9. p. 381-86. 10th rep't p. 376-77. 2 Hagen, H. A. A new species of Simullum with a remariiable pupa ease [S 1 m u 1 i u m picti- pes]. Bost. soc. nat. hist. Proc. 1879. 30 : 305-7. 3 Calvert, P. P. Odonata of New York state. N. Y. ent. soc. Jour. 1895. 3:39-18. Additions, 1S97. 5 :91-95. 394 NEW YORK STATE MUSEUM be found likewise to differ. It has an abundance of dragon flies and caddis flies and of certain Diptera, while certain other groups, notably the stone flies, which require more rapid and rocky streams, are not well represented. Place of insects in natural societies. A very little was done by us in the study of this subject, but that little constitutes part 2 of the present report. Reproductive capacity of insects. But one thing was attempted under this head, and that was the determination of the number of eggs laid by individuals of a number of species, by means of the examination of the ovaries of newly transformed females. This undertaking at once revealed some interesting biologic facts, which might, perhaps, have been inferred in advance, and which may be known, though I have not read of them. These may be stated as follows. 1 In certain insects (as May flies, caddis flies, gnats, etc.) which lack functional mouth parts, and whose adult life is very brief, the eggs are well developed at transformation, and may readily be counted, the difference in size between the developed eggs and the egg rudiments which will not develop being very marked. 2 In other insects (such as the larger dragon flies) the eggs are very immature at transformation, and it is impossible to determine how many of the egg rudiments present at that time will develop into eggs. In other words, the time of the maturing of the eggs is related to the dura- tion of the adult life, and to the amount of food taken during adult life. Having read that the larger dragon flies of the gomphine group live as imagos but a week, I was surprised to find that the eggs of a newly transformed female of Hagenius brevistylus were so immature as to be scarcely recognizable ; but I have since observed that there is in this and in many other large gomphine species an interval of about a month between the period of transformation and that of oviposition. I am inclined to think that the dragon flies which have been kept success- fully only a week in confinement have died of starvation, aiid that in any case the length of imaginal life is not fairly determined so. The few counts successfully made by us from insect ovaries will be found under the discussion of the species on which they were made. Study of the habits of insects. What animals do has always been an interesting subject of inquiry, and probably will always be so. A knowledge of the habits of animals has its own peculiar cul- ture value, now generally recognized. It has a higher scientific value, AQUATIC INSECTS IN THE ADIRONDACKS 395 also, than specialists have always been willing to admit. It has a para- mount economic value also, for it forms the basis of nearly all intelligent economic procedure. We do not yet know how the teeming aquatic life of our streams and lakes and ponds may be manipulated as terrestrial life is manipulated to serve human needs, but this we may learn in due time, and, when we have learned it, the accurate knowledge of the habits of aquatic species of insects will be as necessary then as such knowledge of economic terrestrial species is now. The following pages contain new observations on the habits of many species — occasionally on groups of species. These will be found under the accounts of the groups and the species in part 3 of this report. Food relations of insects and fishes. It was planned from the beginning that we should study fish food, if the opportunity offered for making a real contribution to the present knowledge of that subject. When, through the courtesy of the state fish commission, we were given working quarters in the Adirondack hatchery, we were the more desirous of attacking some of the problems which scientific fish culture needs to have solved; what problems, it was at first a little difficult to decide. In the culture of all animals there are two principal objects to be sought: i) protection for the young, and 2) forage. Past triumphs of fish culture have come from the mastery of the difficulties in securing the first of these, the second has scarcely been seriously undertaken. While extensive food studies have been made by Prof. Forbes and a number of others, from which we have learned in general terms what fishes eat, still there is hardly a fish of which we may say we know what species it eats, at what age, at what season, in what situations, with what choice of food. And so little are the essential features of good foraging ground understood that each planting of fry in a new place is still largely an experiment. So it seemed to me that any new study of fish food should include the study of the feeding grounds, feeding habits, choice of food offered, and conditions that make for the continuance and possible increase of the food supply. The two smaller propagating ponds at Saranac Inn, Bone and Little Green seemed to offer an excellent opportunity for contrasting conditions relative to these points. Bone pond has been well stocked with brook trout for some years, while Little Green, after numerous annual plantings, has remained as barren of trout as ever. Through the earlier part of the season some random collections of food were made from trout caught in gill nets set for suckers; but not till August was there opportunity to make the studies outhned above, and 396 NEW YORK STATE MUSEUM then our efforts met with interference which made their successful prose- cution impossible. Before they were abandoned, however, the stomachs of some 27 brook trout were obtained, and their contents (consisting almost wholly of insects), cleaned and preserved, are now part of the state museum collection. The records of the numerous insects collected during these few days about the shores of Bone pond will be found under their respective species in part 3 of this report, and a brief account of the vegetation, above in the introduction. A random report on the fish food there collected may yet be made from the material I prepared, but it will of necessity lack the features which I counted most essential, unless farther study be made at the pond itself Bullfrogs were common in Little Clear creek, and I collected the stomach contents of 25 of them. Lack of time is the only reason why they have not been studied, and are not reported on at the present time. Life histories of insects. One of the first decisions made with respect to station work was that no greater service could be done for aquatic entomology, pure or applied, than adding as opportunity offered to present knowledge of insect life histories. So long as the species can not be recognized in their immature stages, little progress is possible in food studies, or in quantitative studies of any sort. To this absolutely necessary preliminary work, therefore, much the greater part of our time was given. We were able to work out more or less completely the life histories of about a hundred species of aquatic insects, immature stages of most of which are described in part 3 of this report. Those who have done life history work will not need to be told that this work occupied rather fully the available time of our short session. In order to make part 3 serviceable to teachers and students, I have filled it with keys and tables for determining the orders, families, genera and species of immature stages of aquatic insects, and have illustrated these with special figures explaining the terms used. The several orders will be found to have received very unequal treatment, because we wished to add chiefly to the knowledge of the things least known. For this reason the larvae of Diptera and Coleoptera received much less than a fair share of attention ; for they are already much better known than are the larvae of the other orders treated. More dragon flies than anything else were reared. There are two reasons for this : Saranac Inn is a splendid locality for dragon flies, and I have been rearing dragon flies for a number of years and have learned how to do it. With slight additions from my former breedings, I have AQUATIC INSECTS IN THE ADIRONDACKS 397 been able to give in part 3 an account of the dragon flies (suborder Anisoptera of Odonata) which is almost a monograph of the New York species of that group. But two species of stone flies were seen at Saranac Inn. Both of these were reared, and the descriptions of their nymphs, published herewith^ appear to be the first to be printed for American species. I have been able to rear representatives of all the New York genera of May flieS; and present in part 3 a key for the determination of the nymphs of the same — apparently the first key to be pubUshed for American forms. In the Neuroptera, with its two famiHes having aquatic genera, I have been able to straighten out a tangle in the Sialidae, and to report the dis- covery of larvae and pupae of two genera of Hemerobiidae. These two are both new species of spongilla flies, representing two genera whose larvae live on fresh-water sponges. Entomologically, their discovery was one of the best things of the season. Our account of the aquatic Neu- roptera is thus considerably more complete than any that have hitherto appeared. Mr Betten occupied himself during the intervals of routine operations with the study of the habits and transformations of the caddis flies. He has written the account of this order in part 3. He collected many speci- mens in all stages, and reared four species representing as many genera. His descriptions seem to be the first that have appeared for American larvae. It is a matter of regret that specific determinations could not be had for more of the material in this little studied group. He has pre- pared a table for caddis fly larvae, compiled from the descriptions of European writers and verified, so far as possible, on his own material, and while it is tentative and incomplete, it will doubtless serve a temporary purpose. Aquatic larvae of flies and beetles were abundant at Saranac Inn, but there was little time available for their study after attending to the others mentioned above. A few of the more interesting ones were reared, how- ever, and will be found described in part 3. The three bred Diptera there described make an interesting addition to our knowledge of the larvae of that order. Apparatus and methods. Little need be said on this head. We used the insect nets, cyanid bottles, setting boards, pins, and preserva- tives used by all collectors; but our main stay in aquatic collecting was the sieve net\ which is shown in use in plate 4 ; leaning against a tree in 1 Described and figured ia part O of U. S. nat. mus. Bui. 39, p. 4. 398 NEW YORK STATE MUSEUM plate 5. On the sandy bottoms of these quiet waters it was specially- advantageous. Extensive use was made of white wash bowls, soup plates and saucers in the examination of our catch. We habitually placed teneral specimens of most orders, when found in the cages newly transformed, in paper bags to await the maturing of their colors. For rearing purposes, the screen cage, a simple cylinder of wire screen with a loose cover (described on page 7 of the above mentioned bulletin and shown in operation in plate 5) was most useful. The larger cages of this sort were set down in the sand of the bottom of the creek; smaller ones were set in the hatchery troughs. These, of course, needed a bot- tom, which was supplied by inserting a piece of cloth laid over an open loop of spring wire; the wire when released holding the cloth tightly against the sides of the cage. A still farther modification of this cage consisted in making it smaller, and of fine brass screen, and attaching cork to its sides to float it. Mr Betten made a very good egg-hatching cage out of it by sealing a watch glass in the bottom of it with paraffin, and attaching the cork floats. The eggs were thus kept in flowing water, but could be at once removed to the stage of the microscope without disturbance. I devised for our work at Saranac Inn another type of floating cage that proved so generally useful for minute insects, and was so easily and rapidly constructed that it may be worth while to give a description of it. The accompanying figure shows its construction in the main. With the five little pieces of wood (which Plg.l Floating cage, designed for rearing ^hould be CUt from dry pine) at hand, small Diptera ^ ^^gg ^f ^Y\[s sort Can be put up and ready for use in 10 minutes. The cloth is attached to the wood by means of paraffin, which is melted and applied with a brush. The loose end of the cloth is attached, and the door closed by means of a rubber band stretched between two tack heads over the convex upper edge of one of .^ the wooden side strips (fig. i). This sort of cage ^f was most successful with small Diptera, but not t*^ would invariably fall into the water and die at uve'^'Tn'''Sdinr wliich can be used success- fully for rearing insects that live in standing water. Wooden kit with covering once on transformation. of netting tied on The trap lanterns we used (pi. 4, 5) were also very simply constructed. The idea of them, however, was borrowed from some lanterns I found my AQUATIC INSECTS IN THE ADIRONDACKS 399 friend,' Dr Westcott, using. The lantern part is of the " search light " type to be found on the market, with large parabolic reflector having projecting edges. The trap part consists of a circular flaring band of tin, whose slope con- tinues that of the edges of the reflector, inside which it is pushed and fastened. It has two transversely placed sheets of wire screen within it, arranged as shown in the accompanying figure, and on the lower side within the trap there is an open, detachable cup to hold the cyanid of potassium. It is easily managed and very effective, and the specimens are in the main obtained in good condition. The lantern of the markets has many advantages in the way of conveniences over lanterns of home construc- tion, ^'s- 3 Sectional diagram of lantern trap R, edge of lantern V the globe w edge of parabolic reflector S, the trap a catch for attachment to reflector 6 the entrance between two sheets of screen c detachable cyanid cup Assistance in preparing this report. At the conclusion of my work at Saranac Inn, I went to Cambridge Mass., where, through the courtesy of Mr Samuel Henshaw, I was allowed to spend several weeks determining the specimens I had collected, by comparison with specimens in the museum of comparative zoology. During this time Mr Henshaw showed me many kindnesses and took the trouble himself to determine the names of a number of species. I am also under special obligation to Mr D. W. Coquillett and Mr William H. Ashmead, of the U. S. national museum, for the study and determination of numerous Diptera and Hymenoptera respectively, and for the descrip- tions of new species sent me by them to be published as a part of this report. I am indebted, also, for determinations, to a number of other gentlemen, as follows : Trichoptera, Nathan Banks; Orthoptera, Dr S. H. Scudder; Homoptera, Prof. Herbert Osborn; leeches, Dr W. E. Castle and Dr J. Percy Moore ; moUusks, Frank C. Baker ; an entomostracan, Prof. E. A. Birge. The colored plates have been made by L. H. Joutel. The figures of Trichoptera are by Mrs J. H. Comstock. Those of Diptera, Plecoptera and Ephemerida are by Miss Maude H. Anthony. Those of Odonata are drawn by myself. The figures made from photographs taken by other persons than myself, contain the proper acknowledgment in their legends. 400 NEW YORK STATE MUSEUM Part 2 LIFE OF LITTLE CLEAR CREEK This tranquil little stream (pi. 3), once famous for its trout fishing, traverses the hatchery grounds, and disappears in the woods below under a canopy of overarching alders. It leaves the pond at present by a little artificial fall, runs through a big, tubular iron culvert under the railroad, tumbling over a little bed of stones at the end of the culvert, and then traverses a narrow bit of brookside meadow, bordered by spring bog full of balsam trees. Then it enters the fish ponds. Passing the hatchery, and all the fish gates, it is free again for a little open space before enter- ing the woods below. From the pond to the woods below the hatchery is less than a quarter of a mile; and in this short space the following studies were made. In the undisturbed portion of this course the brook gHdes alternately over beds of rippled reddish sand or percolates through tangled mats of river weed, Potamogeton, and stonework, Nitella, or clumps of bur reed, Sparganium. It has an average depth of perhaps a foot, and a width of about 10 feet. Its depth varies very little with the weather, a continuous downpour of rain for days raising its level but a few inches. In the edges of the woods were seen scattering stemless lady's slippers, and banks of that dainty little favorite of Linnaeus, the twin flower, while the star flower and the bunchberry and the yellow Clintonia and the red elder berry made these places bright in June with their flowers and in August with their brilliantly colored fruit. From this little strip of water we did more or less collecting every day of the session. While we thus gained some general information as to what the stream contained, we were desirous of making our knowledge more exact by quantitative studies, for which unfortunately our breed- ings, requiring constant attention, left us very little time. We did, how- ever, make quantitative studies of the animal life of two Uttle patches of the creek, made a count of the cast skins of dragon flies left along a strip of the bank, made quahtative studies of the insect life of the ripple below the bridge, and of the hatchery pipes and troughs, and made some scattering observations of more or less interest, which will constitute the subject of this chapter. Quantitative studies. These were made from two patches of Little Clear creek, each approximately 15 square feet in surface area. They do not include the animals that slipped through our nets, the AQUATIC INSECTS IN THE ADIRONDACKS 4OI coarsest of which had a mesh of about 2.5 mm square (10 meshes to the inch). The method was the same for both: the plot was staked out; the vegetation. was swept with an air net down to the water line for its aerial forms of life; it was swept again with a water net for its aquatic population; it was then pulled up by the roots and piled in pails and examined a handful at a time in a bowl of clean water, having all the animal life separated from it; the soil of the bottom was then scraped up and sifted for a depth of two or three inches. The material was very quickly gathered up from the plot selected, but the separation of the animal life from the plants and debris was a whole day's work for two or three persons, to say nothing of the time necessary for studying the animals later. These studies, though time-consuming, always yielded the information sought as to the relative numbers of the several species present, and were profitable, also, in quite another way. The careful examination of the situation which they necessitated* always revealed the presence of a number of species not found by more superficial collecting methods, and these were not always the smaller species. First plot. This was in the creek just below the hatchery. The site is shown in plates 4 and 5. The plot extended from the edge of the current in open water 12 to 15 inches in depth, to the bank, a distance of about 5 feet, and a strip 3 feet wide was selected. Two views of it from opposite sides are given in the plates, and its exact site is indicated by the position of the sieve net in plate 4, and is occupied by the cage in the foreground in plate 5. The collections were made July 10. The water was about 3 inches deep at the bank, and descended somewhat regularly toward the current side. Over nearly the whole of the area there was an abundant growth of aquatics, most abundant among which was a species of matted, submerged Potamogeton, intermixed with a variety of filamentous algae, and a httle Nit ell a. The plants which appeared above the water were water-cress, water- spec dwell, and a thin grass which I took to be a species of Leersia. There was no bur reed growing in this plot. The following animals were taken from this plot. Vertebrates I full-grown bullfrog, Rana Catesbiana Shaw, whose stomach contained: 7 full grown snails, Physa heterostropha Say; i dragon fly, $ Calopteryx maculata Beauv.; i Crane fly (unde- termined); I Scarabaeid beetle; 1 female winged carpenter ant ; i Syrphus fly (apparently one of the smaller members of the genus Syrphus); i 402 NEW YORK STATE MUSEUM caddis fly (teneral imago ; undeterminable) ; i water skater, H y g r o - trechus sp.?, and fragments of a number of others; i small bullfrog tadpole ; considerable sand intermixed with fragments of Potamoge- ton leaves; i Entomostracan (undetermined) 3 grown bullfrog tadpoles I young green frog, Rana clamata Daud. The stomachs of the tadpoles and of this frog were empty 1 small salamander, probably an Amblystoma I long-eared sunfish, Lepomis auritus Linn., whose stomach con- tained: 34 little snails,' the largest not over 1.5 mm long, apparently of the genera P h y s a and Limnaea; 12 larvae of gnats (Chironomidae), 2 Chironomus sp.? and 10 Ceratopogon sp.?; i larva of Chau- liodes sp.? in fragments Mollusks 305 snails, retained by our nets, not counting innumerable smaller ones, which fairly covered some of the plants. The 305 were : 292 Physa heterostropha Say 13 Limnaea desidiosa Say 35 small clams, Sphaerium similis Say Leeches 6 specimens 2-4 inches long of Haemopis (Semiscolex) g r a n d i s Verrill A large number of minute glossiphonids, the counting of which was not undertaken Insects The following were taken with a sweeping net from above the surface of the water DRAGON FLIES I Aeschna sp.?, probably constricta Say, found transforming I Ischnura verticalis Say ? . 1 Lestes unguiculata Hagen ^ 2 Argia violacea Hagen 5 and $ 1 Nehallennia irene Hagen % BUGS 43 water skaters, Hygrotrechus sp.? (A greater number got away) 2 Helochara communis Fitch 20 Cicadula sexnotata Fall AQUATIC INSECTS IN THE ADIRONDACKS 4O3 I C. d i V i s a Uhler 7 Liburnia pellucida Fabr., of which two were females, one macropterous, and one micropterous I Chermes sp.? (apterous) 3 Aphids (undetermined) I Lygaeid (undetermined) FLIES, AND OTHER DIPTERA 65 Hydrellia scapularis Loew. A number of other Httle Muscidae, some of them apparently of different species, escaped I crane fly ^ (undetermined) I mosquito $ (undetermined) 3 gnats of three species (undetermined) MISCELLANEOUS I Psocid, Peripsocus madidus Hagen 1 Anthicid beetle, Notoxus anchora Hentz 8 parasitic Hymenoptera: Telenomus longicornis Ashm^ I 3; Brachystropha quadriceps Ashm.^ i $ ; Rhizarcha a s t i g m a Ashm.^ i ^,3 ?s; Aphidius nigripes Ashm.^ 23s The following insects were taken from the water. DRAGON FLY NYMPHS 4 Aeschna constricta Say of various sizes, one full-grown 7 Cordulegaster maculatus Selys 3 Gomphus scudderi Selys 6 Gomphus spicatus Hagen 2 Ophiogomphus aspersus Morse 2 Basiaeschna Janata Say 2 Sympetrum assimilatum Uhler MAY FLY NYMPHS 2 Hexagenia variabilis Etn. 5 Ephemera varia Etn. 3 Ephemerella excrucians Walsh 5 Caen is diminut a Walker. These nymphs are so hard to find among the stems to which they cling very closely, that more were prob- ably present but not seen, 1 Described on p. 586-88. 404 NEW YORK STATE MUSEUM CADDIS FLY LARVAE AND PUPAE 15 Molanna cinerea Hagen 8 Polycentropus lucidus Hagen 2 Halesus no. i (seep. 567) 2 Halesus no. 2 (see -p. c^68) 3 Halesus no. 3 (j'^^ p. 569) 13 unclassified ... 43 in all DIPTEROUS LARVAE AND PUPAE 3 Sepedon fuscipennis Loevv I Bittacomorpha clavipes pupa, probably from the farthest point in shore 7 Simulium venustum Say 8 Tabanid larvae (undetermined) from the bottom in the edge of the channel in open water I crane fly pupa (undetermined) 107 gnat larvae (Chironomidae : all undetermined) of four species Numerous minute Ceratopogon? larvae were observed in the algae associated with still more numerous Limnicolous oligo- chae t es . Second plot. The second plot selected for study was in the upper part of the hatchery grounds, just below the railroad bridge. It was a strip across a bed of bur reeds (shown in the foreground of plate 3) and was similar in form and about equal in area to the preceding. Collections were made precisely as before, but the conditions in the plot were some- what different; the water was of about the same depth, but there was more of a current flowing through the bur reeds. Potamogeton and Nitella and filamentous algae were perhaps a little less abundant in the water here, specially the algae. The date was July 27. The list for this second plot is a short one, in species, if not in individ- uals. It is as follows : I bullfrog, Rana catesbiana Shaw I crawfish (undetermined) MOLLUSKS 13 snails: 11 Campeloma decisum Say; 2 Limnaea de- si d i o s a Say 245 clams, mainly Sphaerium simile Say 117 CADDIS FLIES 27 Molanna cinerea Hagen 22 H y drops ych e sp.?» (near' phalerat a) Hagen (j-/is a Middle legs more approximate at the base than are the fore legs; fourth seg- ment of the antenna slender, erect, about as long as the third segment is wide ; 10th abdominal segment about as long as the ninth Progomphus aa Middle legs not more (usually less) approximate than the fore legs at base ; the fourth segment of the antenna a mere rudiment, orbicular or discoid, much shorter than the third segment is wide ; 10th abdominal segment much shorter than the ninth 43^ NEW YORK STATE MUSEUM b Wing cases strongly divergent on the two sides; lateral lobe of labium blunt at apex Ophiogompbus Ih Wing cases laid closely parallel along the back; lateral lobe of labium ending in a sharp, incurved hook c Abdomen very thin and flat, circular in outline as seen from above; third segment of antenna flat and subcireular ...H a gen iu s cc Abdomen less depressed, ovate to lanceolate in outline, at least twice as long as wide d Third joint of antenna very flat, thin, and in outline circular or broadly oval Lanthus dd Third joint of antenna elongate, linear, little flattened e Dorsum of the ninth abdominal segment rounded, or with a low, obtuse, median longitudinal ridge , Gomphus, sens. lat. ee Ninth abdominal segment with a sharp middorsal ridge, ending in a straight apical spine Dromogomphus The genus Progomphus has not yet been found in New York state, but it will probably be eventually. It ranges from Massachusetts southward and westward across the continent, a single P. obscurus Selys, having been taken in the whole northeastern United States. OPHIOGOMPHUS Four species of this genus are known from New York state. A fifth, O. mainensis Packard is in our lists, but erroneously, I believe. The specimens on which the record is based are in the I^intner collec- tion and in the museum of comparative zoology. I have examined them all, and they certainly belong to O. carolus Ndm., which I believe to be a distinct species. The error seems to have come in the associating of males of O. car o 1 us from New York with the female type of O. m a i n e n s i s. Our four species may be separated as follows. KEY TO THE NEW YORK SPECIES Imagas a Sides of the middle and hind femora yellow ; the inferior abdominal appendage of the male narrower than the superiors, not visible from above 6 No black line on the third lateral suture (fig. 10) of the thorax ; abdominal segments mostly yellowish or brownish, marked with black apically rupinsulensis 66 Third lateral suture of the thorax blaeli, middle abdominal segments black on the dorsal side aspersus aa Sides of the middle and hind tarsi black ; the inferior, abdominal appendage of the male wider than the superiors, its lateral angles visible from above c Forks of the inferior abdominal appendage of the male apparently again forked, the apex of each bearing two strong, upcurved teeth separated by a deep rounded notch „ johannus AQUATIC INSECTS IN THE ADIRONDACKS 437 cc Forks of the inferior abdominal appendage of the male ending bluntly, the obtuse angles bearing low teeth carolus. For the differential characters of other North American species, see my paper " Ophiogomphus " in the Canadian entomologist, 1899, 31 : 233-38, pi. 5. Ophiogomphus rupinsulensis Walsh 1862 Erpetogomphus rupinsulensis Walsh, Acad. nat. sci. Phil. Proc. p. 388 (original description) 1890 Diastatomma rupinsulense Kirby, Cat. Neur. Odon. p. 61 (bibli- ography) 1892 Op hiogo mi)hu 8 rupinsulensis Banks, Am. ent. soc. Trans. 19:351 (listed) 1893 Ophiogomphus rupinsulensis Calvert, Am. ent. soe. Trans. 20 : 242 (description) 1894 Ophiogomphus rupinsulensis Banks, Can. ent. 26 : 77 (listed from Itbaca) 1895 Ophiogomphus rupinsulensis Calvert, N. Y. ent. soc. Jour. 3 : 44 (listed from Ithaca) 1897 Ophiogomphus rupinsulensis Calvert, N. Y. ent. soc. Jour. 5 : 93 (listed from Schoharie) 1897 Herpetogomphus pictus Needham, Can. ent. 29 : 181-82 (descrip- tion) 1899 Ophiogomphus rupinsulensis Needham, Can. ent. 31:236, pi. 5, fig. 3, 12, 21, 30 and 31 1899 Ophiogom phus rupinsulensis Kellicott, Odon. Ohio, p. 53-54 (full description) 1900 Ophiogomphus rupinsulensis, Williamson, Dragon flies Ind. p. 298 (full description) This handsome, widely ranging species has been taken at several places in the state. It was not met with at Saranac Inn. The nymph is unknown. Ophiogomphus aspersus Morse 1895 Ophiogomphus aspersus Morse, Psyche, 7:209 (original de- scription) 1899 Ophiogomphus aspersus Needham, Can. ent. 31: 236, pi. 5, fig. 2, 11, 20 and 29 This species, hitherto known from three somewhat immature specimens in the Museum of comparative zoology, was common at Saranac Inn. Many imagos of both sexes were observed flying over Little Clear creek in the places where the shallow current rippled over sand. The males would fly back and forth a few times and then rest for a time on some prominent twig near shore, generally on the higher bank. They were not difficult to approach or to capture when at rest. Except when oviposit- 438 NEW YORK STATE MUSEUM ing, the females seemed to remain less of the time in the vicinity of the water. The female makes a succession of sweeps back and forth near the head of some little riffle, striking the water, after short flights, again and again near the same place, leaving her eggs in it. Imagos, living and mature, are of a rich, deep green color with the usual oblique stripes of blackish brown. Unfortunately, the color fades readily, even where daylight is excluded. The few imagos which I took the time to gather were nearly all netted while resting on a water pipe which crosses a riffle just below the railroad bridge. The nymphs were very common in the sandy bed of the creek. A great many were raked up and sifted out with a sieve net while collecting for other material. , The cast skins were abundant along the banks through the months of June and July, sticking to whatever support offered, within a foot of the edge of the water. Nymph, (pi. 18, fig. 5) Total length 27.5 mm; abdomen 17.5 mm; hind femur 5 mm; width of head 5 mm, of abdomen 7.5 ram. Legs, genae, sides of the antennae, and lateral margins of the abdomen, hairy; the general dorsum nearly bare; well developed burrowing hooks at the apices of the fore and middle tibiae. Abdomen oval in outline as seen from above, abruptly narrowed on the ninth segment; the loth segment one third shorter than the ninth; the lateral abdominal appendages two thirds as long as the others; very short, subequal lateral spines on the seventh to the ninth segments ; dorsal hooks represented on the second to ninth segments by blunt rudi- ments, which are erect on the front and posteriorly directed on the hind segments, each surmounting a low transverse ridge, which extends across the dorsum and disappears down on the sides on each segment. Anterior two thirds of each segment, including this ridge, prickly granulate; posterior third polished, shining, smooth. Mentum of labium one third longer than wide, dilated beyond its basal third and upturned so as to be flaring upward at its edges ; median lobe distinctly rounded and fringed with flat scales, and bordered be- sides with a row of low, broad, rectangular teeth; lateral lobe incurved, rounded on the apex and not bearing a terminal hook or sharp angle, its internal margin bordered with a row of 12 to 15 low teeth. Color greenish or brownish, with paler and darker mottlings; apical pale rings on all femora; a pair of transversely elongate whitish spots on the dorsum of the seventh abdominal segment, repeated on the eighth seg- ment, but there divided into two spots each side; a whitish spot each side of the loth segment beside the base of the superior appendage; tips of all the abdominal appendages whitish. The nymph is a rapid burrower, trailing along at slight depth through nearly clean sand under the currents, often leaving a faint line behind showing where the tip of the abdomen, upturned for respiration, has pushed the sand grains aside. AQUATIC INSECTS IN THE ADIRONDACKS 439 Ophiogomphus carolus Needham Plate 20, fig. 1-4, 6, 7 1897 Opbiogomphus caroius Needham, Can. ent. 29 : 183, pi. 7, fig. 1, 2, 3, 4, 6, 7 1899 Ophiogomphus carolus Needham, Can. ent. 31 : 235-36, pi. 5, fig. 1 and 28 This species, abundant at Ithaca N. Y. and taken at several other places, in the state, was not met at Saranac Inn. It is a very secre- tive species, few imagos being seen, even where nymphs are excessively abundant. Like the preceding species, the nymphs prefer the sandy beds of running streams. Nymph. Total length 26 mm; abdomen 17 mm; hind femur 4.5 mm; width of head 5 mm, of abdomen 7.5 mm. Body moderately depressed, widest across the sixth abdominal seg- ment, suddenly narrowed on the ninth segment. All ventrolateral mar- gins closely fringed with soft hairs. Color yellowish, the surface abund- andy sprinkled with brownish granulations visible under a lens. Abdomen with lateral spines on segments 7-9, a httle increasing in length posteriorly, but on the ninth segment distinctly shorter than the loth segment. Dorsal hooks on these same segments developed as small blunt posteriorly directed prominences, which hardly surpass the narrow, bare apical band on their respective segments, longest on segment 9, and decreasing in size anteriorly so as to be barely represented on segments 6, 5' 4. Labium as in O. aspersus, but with the 12 to 16 teeth on the inner margin of the lateral lobe a little longer and more angulate at tips. Easily distinguished from the nymph of O. a s p e r u s by the unequal development of the dorsal hooks on the abdominal segments. This species is very common at Ithaca N, Y. Few imagos have been taken at large, and, indeed, they are rarely met with ; but the nymphs may be collected by hundreds from Six Mile creek in spring, and they are very easily reared. Ophiogomphus johannus Needham Plate 20, flg. 5 1897 Ophiogomphus johannus Needham, Can. ent. 29 : 182, pi. 7, fig. 5 1899 Ophiogomphus johannus Needham, Can. ent. 31 : 235, j)l. 5, fig. 9, 18 and 27 The type of this species in the Cornell university collection is from Wilmurt N. Y., and was collected by Prof. J. H. Comstock. Since describing this somewhat immature specimen, I have seen specimens col- lected in Maine by Prof. Harvey, and in western Pennsylvania by Mr Williamson. From these I learn that the terminal abdominal append- ages of the male are not well represented in the figures I have published.^ 1 Can. ent. 1897. 29: 182, pi. 7, flg. 9, 18. 440 NEW YORK STATE MUSEUM The superiors are well enough (and in these the chief distinctions between this species and O. c a r o 1 i n u s Hagen He), but the inferior is incorrect. It is shrunken in the type from which the figure was drawn ; it should be shown almost exactly as in O. carolinus, which is correctly repre- sented in fig. 8 and 17 of the same plate. Mature specimens show also a deep green color on the thorax, and often, the humeral and antehumeral stripes of blackish brown entirely separated at their upper ends. The cast skin, pinned with the type, is not in fit condition for descrip- tion, and the nymph is therefore practically unknown, HAGENIUS There is a single North American species. Hagenius brevistylus Selys 1854 Hagenius brevistylus Selys, Acad. Belg. (2) Bui. 21 : 82 1861 Hagenius brevistylus Hagen, Synopsis Neur. N. Am. p. 114 1890 Hagenius brevistylus Kirby, Cat. Neur. Odon. p. 75 (bibliography) 1890 Hagenius brevistylus Beutenmiiller, Dragon flies vs mosquitos. p. 163 (listed from vicinity of New York) 1892 Hagenius brevistylus Banks, Am. eut. soc. Trans. 19; 352 (listed) 1893 Hagenius brevistylus Calvert, Am. ent. soc. Trans. 20 ; 241 (de- scription) 1894 Hagenius brevistylus Banks, Can. ent. 26 : 77 (listed from Itbaea) 1895 Hagenius brevistylus Calvert, N. Y. eut. soc. Jour. 3 ; 44 (review of lists) 1899 Hagenius brevistylus Kellicott, Odon. Ohio, p. 52-53 (good de- scription) 1900 Hagenius brevistylus Williamson, Dragon flies Ind. p. 282-83 (good description) Nymph 1872 Hagenius brevistylus Cabot, Immature state Odon.pt 2, p. 9, pi. 3, fig. 4 1885 Hagenius brevistylus Hagen, Am. ent. soc. Trans. 72 : 279-80 (very full description) 1897 Hagenius brevistylus Needham, Can. ent. 29:168 (characters stated in table for gomphine nymphs) This big species frequents clear streams, and is common throughout New York state. It is very striking as an adult on account of its great size and black color, and its nymph (pi. 18, fig. 7) is a most grotesque creature. At Saranac Inn the species was common along Little Clear creek. The nymphs were found an the midst of the trash on the bed of the stream, and, during the season of transformation, exuviae dotted the banks rather conspicuously. Few imagos were seen at large. These fly swiftly from one resting place to another about the stream. They are AQUATIC INSECTS IN THE ADIRONDACKS 44I easy to approach and proved not very difficult to capture with a net, when resting on the bridges crossing the stream. The eggs are dropped by the female during flight. She descends and strikes the water repeatedly, at points wide apart: 10 to 20 eggs are liberated at each descent. Thus they are well distributed. Each egg (pi. 19, fig. 2) is somewhat spindle formed in outline with rounded ends, at first of whitish color, becoming yellowish after a few hours. The ovaries of a teneral female from a breeding cage contained no eggs that were nearly mature; a considerable time must elapse after transformation before oviposition can take place. Nymphs of various sizes are always found together. These sizes fall into three or more possible groups of sizes, which may indicate a developmental period of four or more years duration. In other localities I have observed that the nymphs are likely to be found about the deep holes in the creek bed, under lodged driftwood, etc.; but in Little Clear creek they were found everywhere. Even in the shallow fish ponds made by impounding the creek they were so common on the bottom that one or more could be taken anywhere at almost every haul of the sieve net. 11 exuviae were picked from the boarded side of one of the ponds in a distance of 20 yards. The nymph has been well described by Hagen and figured by Cabot (//. cc). There is no need of repeating the description here, since it will be at once recognized by plate 18, figure 7, and by the characters given in the table. LANTHUS This genus includes the smallest and the daintiest of our Gomphinae, black species, striped with green. Its two species probably both occur within the state of New York, though but one of them, L. parvulus, has been recorded for the state hitherto. They may be easily distin- guished as follows. Abdomiual appendages black parvulus Abdominal appendages yellow or whitish albistylus Lanthus parvulus Selys 1854Gomphus parvulus Selys, Acad. Belg. (2) Bui. 21:56 1857 Gomjthus parvulus Selys, Monographie des Gomphinae, p. 157 1861 Gomphus parvulus Ragen, Synopls Neur. iST. Am. p. 109 1890 Aeshna parvula Kirby, Cat. Neur. Odon. p. 65 (bibliography) 1892 Gomphus parvulus Banks, Am. ent. soc. Trans. 19 : 352 (listed) 1893 Gomphus parvulus Calvert, Am. ent. soe. Trans. 20:242 (descrip- tion) 442 NEW YORK STATE MUSEUM 1894 Gompbus parviilus Banks, Can. ent. 24 : 77 (recorded from Ithaca) 1895 Gomphus parvulus Calvert, N. Y. ent. soc. Jour. 3:44 (recorded from Iibaca) 1897 Gompbus parvulus Needbam, Can. ent. 29 : 165, 166, 167 (made tbe type of a new genus, L a n t b u s : nymph, found at Ithaca N. Y. identified with those described by Dr Hagen from Eoeky creek Ky. in Traus. Am. ent. soc. 1885, 12:281 and doubtfully referred by him toUropetala (Tacbopteryx) tboreyi: nym^jb figured, pi. 7, fig. 8-10) The habits of the images of this species are unknown. The few speci- mens 1 was able to obtain at Ithaca in 1897 were all bred, and I saw no imagos at large. The nymphs are very interesting little fellows, quite as different in certain habits as they are in structure and appearance from other gomphines. They seem to prefer little, trickling streams fed by springs, and burrow in beds of sand in the deeper parts. They are more agile than other gomphine nymphs, burrow more rapidly, and, when with- drawn from the water, unlike others, they feign death, and lie quite still for a number of minutes. On account of this habit, as well as on account of the mottled coloration of the body, they are much more diffi- cult to detect while collecting than are the others which begin active struggling as soon as the net is lifted above the water. Nymph. (PL i8,fig.6and2o,fig.8-io) Total length 23 mm; abdomen 14 mm; hind femur 5 mm; width of head 5 mm, of abdomen 6 mm. Body somewhat depressed, a little hairy on the genae and on the tibiae, elsewhere bare ; head concave on the hind margin ; antennae, with the two basal segments short and angular, the first a little larger, the articulation between the first and second a little oblique, the third segment obliquely oval, flat, one third longer than wide, with a depressed smooth oval area within the scurfy pubescent marginal rim, the fourth segment a minute round rudiment, at the inner apical angle of the third ; labium mentum a little longer than broad, its front border appearing convex by the rounded fringe of scales, in the midst and at the base of which are four to six brown, minute quadrangular teeth ; lateral lobe little arcuate, the distal angle produced and incUned internally, but hard- ly differentiated from the six teeth on the inner margin, these teeth all largest in the middle, and a line connecting their summits would be con- vex internally. Abdomen stocky, widened to the seventh segment, and thereafter nar- rowed, most narrowed on the ninth segment; no dorsal hooks at all, but a median impressed line ending on the seventh segment; lateral spines well developed on segments 8 and 9, on 9 broadly triangular, and con- siderably shorter than the loth segment, against the sides of which they are closely applied; loth segment one half as long as the eighth, one third as long as the ninth, three fifths as long as the superior and inferior appendages; three fourths as long as the others. AQUATIC INSECTS IN THE ADIRONDACKS 443 Lanthus albistylus Selys 1878 Gomphus albistylus Selys, Acad. Belg. (2) Bui. 46:460 (original description of $ from Maine) 1878 Gomphus naevins Acad. Belg. (2) Bui. 46:462 (original description of 5 from Pennsylvania) 1890 Aeshna albistyla Kirby, Cat. Neur. Odou. p. 66 (bibliography) 1890 Aeslina naevius Kirby, Cat. Neur. Odon. p. 66 (bibliography) 1892 Gomphus albistylus Am. ent. soc. Trans. 19 : 351 (listen) 1892 Gomphus albistylus Banks, Am. ent. soc. Trans. 19 : 352 (listed) 1893 Gomphus albistylus Calvert, Am. ent. soc. Trans. 20:242 (descrip- tion) 1898 G o m p hus albistylus Harvey, Ent. news. 9 : 63-65 (description, figure and notes) Still known only from Maine and Pennsylvania, in which states, how- ever. Prof. F. L. Harvey and E. B. Williamson, respectively, have col- lected a goodly number of specimens of both sexes. There is in the Cornell university collection a specimen lacking half the abdomen, probably of this species, from North Carolina. The nymph is not known (unless the ones described by Hagen should prove to be of this species, instead of L. parvulus, as I have supposed. I have not compared my own nymphs with Hagen's types). GOMPHUS The United States is the center of abundance for this great genus, and it is nowhere better represented than in New York state. Our list includes 17 regional species, only two of which have not yet been act- ually taken in the state. They are species of medium or large size, often very local, and locally very abundant. They are found about water, and in woods and copses adjacent to it. They are often flushed from a bare path or roadway ; they are perhaps most commonly seen resting flat on the surface of some log which stretches its length across a stream; they rarely perch atop a slender twig after the manner of the skimmers (Hbellulines). Our species fly mainly in June, though G. scudderi is a midsummer, and G. spinicepsa late summer- species. The nymphs form a most important part of the bottom fauna in all clear waters. They are active burro wers, taking their prey either on or beneath the surface of the bottom silt. They are very rapacious, and will eat almost any living animals small enough to be held by their pow- erful grasping labia. The nymphs are highly specialized for their pecu- Har Hfe. They are more unlike than are the imagos, and in general more /|/1/) NEW YORK STATE MUSEUM easily referable at a glance to their place in the genus. The images ex- hibit with shght variations one color pattern, one plan of venation, one habitus, and are therefore not easy to distinguish. I give below an arti- ficial key to aid in the recognition of our species, and follow it with a synoptic arrangement of the genus, in which is included a statement of the more important characters of lesser groups within the genus. For all of these I prefer to retain the old generic name Gomphus till more of the nymphs are known. ARTIFICIAL KEY TO IMAGOS 1 Face entirely yellow 2 Face yellow, trausversely bauded with black 10 Face snifused with brownisb black ; large, very elongate species, with a dis- tinct anal loop of a single cell, a pair of narrow oblique yellow stripes on the dark background of the thoracic dorsum 14 2 Hind margin of the occiput with a distinct median tooth villosipes " without " 3 3 Tibiae yellow externally 4 " black " 7 4 Abdominal segments 7-9 strongly dilated about as wide as the thorax fraternus Abdominal segments 7-9 little dilated, much narrower than the thorax... 5 5 Length under 45 mm exilis Length over 45 mm 6 6 Superior abdominal appendages of the male with a sharp inferior tooth ; vulvar lamina of the female composed of two acute triangular lobes, one fourth as long as the ninth segment si^icatus Superior abdominal appendage of the male with a low inferior lobe; vulvar lamina of the female composed of two low rounded lobes, and hardly longer than one 10th of the ninth segment sordid us 7 Length under 40 mm abbreviatus Length over 40 mm and under 50 mm 8 Length over 50 mm 9 8 Abdominal segments 7-9 greatly dilated, as wide as the thorax ve ntri c osus Abdominal segments 7-9 little dilated, much narrower than the thorax quad ri color 9 Dorsum of the 10th abdominal segment and the superior appendages black descriptus Dorsum of the 10th abdominal segment and the superior appendages yellow ._ furcif er 10 Yellow of the thoracic dorsum reduced to two narrow, oblique, isolated, yellow stripes scudderi Yellow stripes of the thoracic dorsum broader, not isolated, dilated at their anterior ends 11 11 Side (anterior face) of the hind femora yellow amnicola Sides of the hind femora black 12 AQUATIC INSECTS IN THE ADIRONDACKS 445 12 Two cells between veius Ai and A2 at their origin; length less than 45 mm brevis A single cell between veius Ai and A2 at their origin ; length more than 45 mm 13 13 Midlateral thoracic stripe complete ; length about 46 mm adelphus Midlateral thoracic stripe interrupted, not exteuding above the spiracle : length about 54 mm vastus 14 Ninth abdominal segment little longer than the eighth, ground color brown plagiatus Ninth abdominal segment much longer than the eighth; ground color black spiniceps SYNOPTIC ARRANGEMENT OF THE GENUS, IMAGOS AND NYMPHS Subgenus gomphus Imago. Generally with two cells between veins Aj and A2 at their origin, when with but one, that one generally longer (in the axis of the wing) than wide, and never so thickened in its bordering veins as to con- stitute a distinct anal loop ; hind femora similar in the two sexes ; pos- terior genital hamule in the male generally nearly vertical in direction, at least not directed anteriorly; eighth abdominal segment generally squarely cut, rarely a very Httle longer on the dorsal than on the ventral side. Nymph. Abdomen wider than the head; lateral spines on abdominal segments 6-9 ; an impressed middorsal line on abdomen more or less evident, often appearing to divide the segments longitudinally, present even on the bases of segments which may bear dorsal hooks apically ; median lobe of labium straight on anterior border, or very slightly con- vex, and not bearing a median tooth. A synthetic group, offering evident points of departure for the three subgenera which follow it. KEY 1) Ninth abdominal segment a little shorter than the eighth ; two cells be- tween veins Ai and A2 at their origin; male with the fork of the in- ferior abdominal appendage not extending laterally beyond the superiors ; female with a low carina on the vertex, at whose extremities arise black thorn! ike spines; small species. a) Imago Face yellow : Nymph, Length when full grown 24 mm ; lateral spine on the sixth abdominal segment less than half the length of the one on the seventh segment G. abb re vi at us aa) Imago Face transversely lineate with black. Nymph Length when full grown 26 mm ; lateral spine on the sixth abomlnal segment more than half as long as the one on the seventh segment G, brevis 2) Ninth abdominal segment as long as the eighth, or often a very little longer; inferior abdominal appendage of the male widely forked, its 446 ■ NEW YORK STATE MUSEUM apices appearing at the sides of the superiors ; female generally without thornlike vertical spines. a) Imago A single cell between veins Ai and A2 at their origin; seg- ments 8 and 9 of abdomen of about equal length, 7-9 greatly dilated, in width almost equaling the thorax; vulvar lamina of the female about half as long as the ninth abdominal segment. Nymph with a broad, obtusely pointed abdomen ; lateral spines on the ninth abdominal segment twice as long as the 10th segment, the latter segment thus appearing incased in the ninth ; median impressed line on abdomen distinct, and no dorsal hooks except the merest rudiments on segments 8 and 9. Z>) Face of imago lineate with black. Length of full grown nymph 29mm G. adelphus ii) Face of imago entirely yellow. Length of full grown nymph 33 mm G. fr a tern us aa) Imago Normally two cells between veins Ai and A2 at their origin ; ninth abdominal segment a little longer than eighth; segments 7-9 less dilated ; vulvar lamina of female one third to one 10th as long as the ninth segment. iVj/mj)7i with lanceolate, pointed abdomen ; the lateral spines on the ninth segment generally shorter than the 10th segment and not inclosing it; dorsal hooks represented by rudiments of some of the segments before the eighth; impressed middorsal line visible only toward the bases of the middle segments. &) Imago Length 45 mm ; legs all black ; nymph unknown G. quadricolor 1)1)) Imago Length over 50 mm ; fore femora yellow or green below ; nymph with very low, obtuse, inconspicuous rudiments of dorsal hooks, c) Imago Tibiae black externally ; inferior abdominal appendage male with an inferior tooth ; vulvar lamina of the female about one third the length of the ninth abdominal segment. Nymph with about ' eight to 10 teeth on the inner margin of the lateral lobe of the labium G. descriptus cc) Imago. Tibiae yellow externally ; superior abdominal append- age of the male with an obtuse inferior lobe; vulvar lamina of the female about one lOtb as long as the ninth abdominal segment. Nymph with about six to eight teeth on the inner margin of the lateral lobe of the labium G. sordidus bM) Imago Length about 48 mm; tibiae yellow externally ; yellow on the dorsum of abdominal segments 9 and 10. Nymph with pointed rudimentary dorsal hooks on segments 6-9 G, exilis Subgenus gomphurus Imago. A single cell between veins Ai and A2 at their origin, hav- ing a thickened margin, forming an anal loop; abdominal segments 7-9 greatly dilated, as wide as or wider than the thorax : eighth segment cut squarely on apex ; posterior hamule of male perpendicular ; hind femora similar in the two sexes. AQUATIC INSECTS IN THE ADIRONDACKS 447 Nymph. Abdomen a little wider than the head, the ninth segment hardly longer than the eighth ; lateral spines on segments 6-9, a well marked middorsal impressed line extending to the eighth segment, and very minute rudiments of dorsal hooks on segments 8 and 9 ; tibial bur- rowing hooks large; front border of median lobe of labium straight, lateral lobe with its terminal hook bent inward at almost or quite a right angle; apex of abdomen regularly narrowed beyond the middle. KEY a) Imago Face entirely yellow; nymph, unknown G. ventricosus aa) Imago Face with ijarrow black lines on sutures ; sides of hind femora yellow ; nymph unknown G. amnicola aaa) Imago Face with broad transverse bands of black ; hiud femora black ; abdominal segments with basal rings of yellow ; nymph with the lateral spines of the ninth segment less than half as long as the 10th segment G. scudderi aaaa) Imago Face with broad transverse bands of black; hind femora black; yellow of middle abdominal segments restricted to triangular spots on the dorsum; nymph with the lateral spines of the ninth segment about as long as the 10th segment G. vastus Subgenus stylurus Imago. A single cell between veins Ai and Ag at their origin, that cell strongly bordered ; abdominal segments 7-9 not greatly dilated (much narrower than the thorax), but considerably elongated; eighth segment cut squarely at apex ; posterior genital hamule of male strongly directed anteriorly ; hind femora similar in the two sexes. Nymph. Abdomen narrower than the head, and greatly elongated ; tibial burrowing hooks very small ; lateral spines, middorsal suture and dorsal hooks of abdomen as in Gomphurus; ninth abdominal seg- ment longer than the eighth, sometimes twice as long. KEY a) Imago. Ninth abdominal segment of imago mnch shorter than the seventh. Nymph with the lateral spines of the ninth abdominal seg- ment longer by half than the 10th segment .- G. plagiatus aa) Imago with segments 7 and 9 of abdomen about equal in length. Nymph, with the lateral spines of the ninth abdominal segment shorter by half than the 10th segment * G. spiniceps Subgenus arigomphus Imago. Two cells between the base of veins Ai and A3 at their origin ; eighth abdominal segment obhquely cut at apex, longer on the dorsal side; hind femora different in the two sexes, in the male hairy, and in 448 NEW YORK STATE MUSEUM the female armed with numerous stout spines below; posterior hamule of male directed posteriorly. Nymph. Abdomen wider than the head ; flattened, lanceolate pointed, suddenly narrowed on the ninth segment, which is longer than its apical width; no impressed middorsal line, instead, a ridge without distinct dorsal hooks; lateral spines on segments 7-9 or 8-9, none on segment 6; median lobe of labium prominently rounded or dome shaped, and usually bearing, besides the usual brush of flattened hairs, a median tooth. KEY a) Imago with abdominal appendages black ; superiors of male with an in- ferior tooth ; nymph with bare median narrow ridge on the abdomen; lateral spines on segments 7-9 G. spicatus aa) Imago with a tooth in the middle of the occipital border. Abdominal appendages yellowish, no inferior tooth on the male superiors. Nymph with an obtuse scurfy or rough pubest-ent middorsal ridge on the abdo- men ; lateral spines on segments 7-9 G. villosipes aaa) Imago with no tooth in middle of hind border of the occiput; abdominal appendages yellow ; male superior appendages apparently bifurcated at apex; nymph unknown G. furcifer Gomphus abbreviatus Selys 1878Gomphus abbreviatus Selys, Acad. Belg. (2) Bui, 46 : 464 (original description) 1890 Aeshna abbreviata Kirby, Cat. Neur, Odon. p. 66 (bibliography) 1892 Gomphus abbrev i atus Banks, Am. ent. soc. Trans. 19 : 351 (bibli- ography) 1893 Gomphus abbreviatus Calvert, Am. ent. soc. Trans. 20:243 (de- scription) This species is not recorded from New York state. In June of 1897 I found some nymphs at Ithaca N. Y. in Fall creek opposite the Cornell insectary, and bred a few of them. The imagos I did not observe at large. Nothing has been written as to their habits. The species appears to be distributed through the northeastern states as far south as Penn- sylvania. It was not found at Saranac Inn. Nymph. Measures in length 23-24 mm; abdomen 14 mm; hind femur 5 mm; width of head 5 mm, of abdomen 6.5 mm. It diiffers from G. b r e V i s nymph only in size and in the relative length of the foremost lateral spines on the abdomen, characters already stated in the table; there is no need, therefore, of a separate description of it, since G, b r e V i s is described in full below, and the description would be but repetition of the characters stated for that species. I will therefore add but a note as to the differences of the situations in which I found the two nymphs : a b b r e v i a t u s in the rocky basins of a gorge trav^ersed by a foaming creek, destitute of the commoner large aquatic plants ; b r e v i s , in the bed of a reed-choked, slow flowing, upland stream. AQUATIC INSECTS IN THE ADIRONDACKS , 449 Gomphus brevis Hagen 1854 Emmons, Agric. N. Y. v. 5, Insects, pi. 15, fig. 2, (colored figin'e, no name or description) 1878 Go mp bus brevis Hagen, Acad. Belg. (2) Bui. 46 : 461 (original de- scription'* 1890 Aesbna brevis Kirby, Cat. Neur. Odon. p. 66. (listed) 1892 Gomphus brevis Banks, Am. ent. soc. Trans. 19:351 (listed) 1895 Gomphus brevis Calvert, N. Y. ent. soc. Jour. 3:45 1897 Gomplius brevis Calvert, N. Y. ent. soc. Jour. 5 : 93 This species, originally described from specimens obtained by Dr Lintner at Schoharie N. Y., v/as common at Saranac Inn. I captured but a single imago, and saw but few, but the nymphs were very plentiful in Little Clear creek. The few imagos seen flitted about the edge of the water in the warm sunshine in a manner very similar to that of other small gomphines; oviposition was not observed. The season of transformation was apparently about ended on our arrival at Saranac Inn in the middle of June ; exuviae which I, having bred abbreviatus before, was able at once to refer to this species were thickly sprinkled over the boards on the sides of the fish ponds made by impounding the creek. I collected many of them during the first two or three days of our stay; thereafter but few additional exuviae appeared, the season being past. The species was not bred, but there can be scarcely a doubt that the nymphs, referred to it here by supposition, belong to it. The original description of this species is not generally accessible in this country ; no other has been published, apparently. Therefore, be- lieving th.it an accessible English description will be of service to some, I give a brief one below, and follow it with a description of the nymph, hitherto unknown. Imago. Measures in total length 42-45 mm ; abdomen 30-33 mm ; hind wing 25-27 mm. Colors black and green ; face with heavy black lines on all its sutures and margins, these lines sometimes overspreading the whole face except the upper part of the frons and the sides of the post-clypeus and the labium ; rear of the frons, all of the vertex (excepting the tips of its horns), and the front and lateral margins of the occiput black; the occi- put otherwise clear yellow, distinctly wider and more convex in the female. Middorsal thoracic stripe short, with parallel sides, narrowed to a median line before the collar, divided by a yellow carina ; humeral and antehum.eral stripes contiguous near their upper ends, leaving an isolated yellow triangular spot above, and an isolated narrow line below between them; midiateral thoracic stripe incomplete above, disappearing above the spiracle; stripe on the third lateral suture complete but narrow; legs all black ( ,3 ) or with the front femora green beneath ( $ ). Wings hyaline; costa black; stigma brown. 450 NEW YORK STATE MUSEUM Abdomen black with a middorsal line of yellow triangles pointing pos- teriorly, elongate and twice constricted on the basal segments, becoming very short and restricted to the base on several segments before the ninth, and entirely absent from the ninth and loth segments. There is a line of yellow at the extreme apex of some of the terminal segments beyond the spiniferous, apical, transverse carina; the nth segment, "anal tubercle," of the female yellow except at the sides; appendages black; sides of segments 1-3 mainly yellow ; segments 4-7 with small basal lateral yellow spots in the female; the slightly expanded lateral margins of segments 8 and 9 yellow in both sexes. Described from a $ from Saranac Inn taken July 2, 1900, and from a $ collected on Mt Tom in Massachusetts ; the larger measurements are for the female specimen. This Saranac Inn female was the first imago seen there, and it will be noted that the date is two weeks after the nymphs had ceased emerging. I think this time represents the period necessary for the maturation of the eggs after transformation. A similar lapse of time between the period of transformation and that of oviposition was observed in the case of a number of other gomphines. I believe these insects live longer as imagos than is commonly supposed. As is well known, they will die within a week after transformation if kept in confinement, but apparently no one has tried feeding them well while keeping them as yet. May they not die of starvation ? Nymph. PI. 18, fig. 3. Total length 26 mm; abdomen 17 mm; hind femur 5 mm; width of head 5 mm, of abdomen 6.5 mm. Body depressed, abdomen with sides parallel to the eighth segment, then rather abruptly narrowed to an obtuse point; lateral spines on seg- ments 6-9, the margins which bear them thin, and on the ninth segment finely spinulose serrate ; spines of the ninth segment about as long as the loth segment ; very minute rudiments of dorsal hooks on segments 8 and 9; before the eighth segment there is an observable trace of the median impressed longitudinal line of the typical Gomphus nymph. The loth segment is about one third the length of the ninth. The mentum of the labium is rather short, little longer than broad ; the lateral lobe is very moderately arcuate, its apex forming a short end hook not greatly differentiated from the teeth before it; of these teeth on the inner margin of the lateral lobe there are eight or nine, unequal, the mid- dle ones being shghtly largest, angulate, sharp, the fine of their apices being convex internally, rather than concave, as in all the following members of the genus. The color, usually obscured by dirt excepting after molting, is greenish brown, with darker motthngs arranged in transverse bands on abdominal segments, scars on abdomen surrounded with paler color. The third antennal segment is linear, a little depressed and widened apically, hairy, as is usual, on the margins. AQUATIC INSECTS IN THE ADIRONDACKS 45I Gomphus fraternus Say 1839 Aeschna fraterua Say, Acad. nat. sci. Phil. Jour. 8: 16 1861 Gomphus fraternus Hagen, Synopsis Neur. N. Am. p. 104 1862 Gomphus fraternus Walsh, Acad. nat. sci. Phil. Proc. p. 393 1863 Gomphus fraternus Walsh, Ent. soc. Phil. Proc. 2 : 238 1890 Aeshna fraterna Kirby, Cat. Neur. Odon. p. 66 (bibliography) 1892 Gomphus fraternus Banks, Am. ent. soc. Trans. 19 : 352 (listed) 1894 Gomphus fraternus Banks, Can. ent. 26 : 77 (listed from Ithaca) 1895 Gomphus fraternus Calvert, N. Y. ent. soc. Jour. 3:45 (listed from Ithaca) 1897 Gomphus fraternus Van Duzee, N. Y. ent. soc. Jour. 5 : 89 (listed from Niagara) 1897 Gomphus fraternus Calvert, N. Y. ent. soc. Jour. 5:93 (listed) 1899 Gomphus fraternus Kellicott, Odon. Ohio, p. 59 (description and figures) 1900 Gomphus fraternus Williamson, Dragon flies Ind. p. 289 (descrip- tion and figures) 1897 Gomphus fraternus Needham, (nymph) Can. ent. 29, pi. 7, fig. 11 and 12 (figures only; those are reproduced in plate 20 of this bulletin) This vigorous species seems to prefer the larger bodies of water. The imago is a very strong flyer. It skirts the edge of streams with dashing sweeps which seem to proclaim it master of the situation. I have several times seen it feeding on other dragon flies as large as Mesothemis simplicicollis. The nymph is an active burrower in the bare clay bottoms of streams and lakes under water of considerable depth. I repeat herewith the figures of the nymph (cited above) and add a brief description. Nymph. Length 31 mm; abdomen 20; hind femur 6.5 ; width of head 5, of abdomen 9 ; colors obscured ; margins all hairy ; tibial bur- rowing hooks very strong, as long as tibia is wide. Third segment of antenna twice as long as the first and second together, hairy on margins ; fourth a minute ovoid rudiment. Mentum of labrum (pi. 20,' fig. 12) squarish before the contracted basal fourth; median lobe very slightly convex, densely frmged; lateral lobe bluntly angular at the apex with 7-1 1 small teeth on inner margin. Abdomen (pi. 20, fig. 11) broad, depressed, with sides parallel most of its length, abruptly narrowed beyond the sixth segment, minute dorsal hooks on segments 8 and 9 ; median groove on anterior segments, well developed lateral spines on segments 6-9 those of 9 about equaling the appendages. Gomphus adelphus Selys 1857 Gomphus adelphus Selys, Monographie des gomphines, p. 413 1861 Gomphus adelphus Hageu, Synopsis Neur. N. Am. p. 104 1896 Aeshna adelpha Kirby, Cat. Neur. Odon. p. 67 (bibliography) 1892 Gomphus adelphus Banks, Am. ent. soc. Trans. 19 : 351 (listed) 452 NEW YORK STATE MUSEUM 1895 Gomphus adelphus Calvert, N. Y. ent. soc. Jour. 3 : 45 (listed from Bethlehem) 1897 Gomphus adelphus Calvert, N. Y. ent. soc. Jour. 5:93 (listed from Kenwood) The specimens above described and listed were collected in New York state by Drs Fitch and Lintner. The species is also known from Massachusetts. I have not met with it in either immature or adult stage, and know nothing of its habitat or habits. Dr Hagen has carefully described a nymph from Cambridge Mass., referable by supposition to this species in the Trans. Am. ent. soc. 1885, 12 : 262. If the nymph be full grown, as he thought, there can be but little doubt that it belongs to this species. However, his description agrees in every point excepting size with G. fraternus bred by me in Illinois. Unfortunately I did not get time while in Cambridge for the comparison of my own nymphs with Hagen's types. I have stated the difference in size in the foregoing table. These being all the differences known to me, I have nothing farther to add concerning this species. Gomphus quadricolor Walsh 1863 Gomphus quadricolor W-ilsh, Ent. soc. Phil. Proc. 2 : 246 1890 Aeshna quadricolor Kirby, Cat. Neur. Odon. p. 66 (bibliography) 1892 Gomphus quadricolor Banks, Am. eut. soc. Trans. 19: 352 (listed) 1899 Gomphus quadricolor Kellicott, Odon. Ohio, p. 58 (description and figures) 1900 Gomphus quadricolor Williamson, Dragon flies Ind. p. 288-89 (de- scription and figures) This species is abroad during the first two weeks of June. It has not hitherto been reported from New York state, but I have seen a specimen collected near Ithaca. The nymph is unknown. I have not seen the imago alive. Prof. Kellicott wrote of it, " It rests on rocks projecting from rapids, or on the banks near by the most rapid parts of streams." (Odon. Ohio, p. 58) Gomphus descriptus Banks 1896 Gomphus descriptus Banks, N. Y. ent. soc. Jour. 4 : 195 (from Ithaca) 1897 Gomphus descriptus Calvert, N. Y. ent. soc. Jour. 5 : 95 (listed) 1900 Gomphus descriptus Williamson, Dragon flies, lud. p. 293 (descrip- tion and figures) 1897 Gomphus descriptus Needham, Zool. bul, 1:103-13 (digestive epithelium) This species is quite abundant at Ithaca, and has not as yet been reported from any other locaHty. It flies during the latter part of May and the first week of June. I found a meadow beside a patch of woods AQUATIC INSECTS IN THE ADIRONDACKS 453 a favorite foraging ground for the adults ; May 30, 1897, and for several days thereafter, they were flitting about this meadow in numbers, but were so active that it required some time to capture many specimens. I collected once enough nymphs to fill a quart fruit jar from Six Mile Pig. 11 Genitalia of Gomplius descriptiis Banks, a lateral view of end of abdomen of male; & lateral view of the genital hamules of the male (inverted position) ; c dorsal view of the terminal abdominal appendages of the male ; d ventral view of the vulvar lamina and end of abdo- men of female creek near Ithaca in an hour. I will mention a variety of this species which occurred at Saranac Inn, before describing the nymph. I bred the species at Ithaca and collected the variety at Saranac Inn, but am unable to find any differences between them in the immature stages ; the description will therefore stand for both. G. descriptus borealis n. var. This is the dragon fly figured by Hagen in Selys's Monographie des Gomphines (pi. 9, fig. 2, dorsal view) y A,\jui^ ?-^ Fig. 12 Gomphus descriptus borealis n. I'ar. Letterlngasinfig.il asGomphus spicatus. There are several points of difference between this insect and G. spicatus, one of the most obvious of which is the yellow color of the external face of the tibiae in s pi c a t u s. The appendages and the proportions of the apical segments of the abdomen are different. 454 NEW YORK STATE MUSEUM The variety differs from the typical d e s c r i p t u s, so far as observed, only in the form of the appendages of the male abdomen. These differences are shown in the accompanying figures, wherein it will be seen there is a radical difference in the form of the anterior hamule of the male, and that in the variety the superior appendage is shorter, less acute at apex and with the inferior tooth directed more inward than in the typical descriptus. The variety was first received from Franconia N. H. among some specimens sent me by Mrs Annie Trumbull Slosson. It was not uncommon about Saranac Inn. A few were observed foraging about the Otisville road, and a few others were seen resting on the bare sand of the railroad embankment at the outlet of Little Clear pond. Oviposi- tion was not observed. Nymph, (PI. i8, fig. 4) Total length 32 mm; abdomen 20 mm; hind femur 5.6 mm; width of head 5 mm, of abdomen 7 mm. Body depressed, lanceolate, hairy on all lateral margins, tapering beyond the middle of the rather pointed abdomen. Colors generally entirely obscured by adherent dirt, but after molting there is often seen a darker band across the base of each abdominal segment. Third segment of the antenna depressed and somewhat widened api- cally. Labium with the mentum one third longer than wide; median lobe nearly straight on its front border, fringed with flat hairs, but unarmed ; lateral lobe regularly incurved with a long terminal hook, exceeding the six to eight teeth before it on the inner margin. Lateral spines on abdominal segments 6-g, sometimes obscured by tufts of hairs on the sixth segment, those of the ninth segment short, hardly surpassing the base of the loth segment, straight, but not closely appressed. loth segment half as long as the ninth, and a little shorter than the appendages; lateral appendages a sixth to a seventh shorter than the others. Dorsal hooks represented by low, inconspicuous rudi- ments on segments 3-9, with traces of the median impressed line on the anterior end of the middle segments. Nymphs of this species were taken at two places : Colby pond, just west of the town of Saranac Lake, and Bone pond. They were associ- ated with and greatly outnumbered by G. sp i c a t u s in both places. Gomphus sordidus Hagen 1854 Gomphus sordidus Hagen, Acad. Belg. (2) Bui. 21 : 54 1861 Gomphus sordidus Hagen, Synopsis Neur. N. Am. p. 106 1875 Gomphus lividus Hagen, Host. soc. nat. hist. Proe. 18 : 45 (listed) 1893 Gomphus minutus Calvert, Am. ent. soc. Trans. 20 : 244 (5 only) 1899 Gomphus lividus Kellicott, Odon. Ohio, p. 66 (description and figures) AQUATIC INSECTS IN THE ADIRONDACKS 455 1897 Gomplius umbratus Needham, Can, eut. 29:184 (described, from Ithaca) 1900 Gomphus sordidns Williamson, Dragon flies Ind. p. 292 There are plenty of descriptions and figures of this troublesome species, as will be seen from the above bibhography. I found both imagos and nymphs associated with the same stages ofG. descriptus Banks at Ithaca. It is entirely similar to that species in habits, and in appearance, but will be readily distinguished by the characters given in the tables. The nymph is not easy to distinguish, however; in fact, I find it necessary to make a microscopic examination of the labium before being sure as to the species. I bred a good many specimens at Ithaca. By way of description, I will only say that it is entirely similar to the nymph of d e s c r i p t u s , so far as known to me, excepting in the dif- ferential character stated in the table. Gomphus exilis Selys 1854 Gomphus exilis Selys, Acad. Belg. (2) Bui. 21 : 55 1861 Gomphus exilis Hagen, Synopsis Neur. N. Am. p. 108 1872 Gomphus exilis Hagen, Bost. soc. nat. hist. Proc. 15 : 273 1875 Gomphus exilis Hagen, Bost. soc. nat. hist. Proc. 18 : 45 1885 Gomphus exilis Hagen, Am. ent. soc. Trans. 12:263-64 (descrip- tion of the nymph, and remarks on distribution) 1893 Gomphus exilis Hagen, Am. ent. soc. Trans. 20 : 243 (description) 1894 Gomphus exilis Banks, Can. ent. 26 : 77 (listed from Ithaca) 1895 Gomphus exilis Calvert, N. Y. ent. soc. Jour. 3 : 45 (listed from Keeseville) 1899 Gomphus exilis Kellicott, Odon. Ohio, p. 65 (description and iigure) 1900 Gomphus exilis Williamson, Dragon flies Ind. p. 293 (description and figure) This is one of the most generally distributed, and perhaps the com- monest of the gomphines of the northeastern United States. At Saranac Inn it was abundant, flitting by every roadside throughout the month of June and well along into July. The nymphs were found in all waters, and about the first of July the exuviae fairly sprinkled every bank. Few imagos were observed in the immediate vicinity of the water, after leaving it at transformation, and these few were mostly females ovipositing. These spin along through the air at a lively rate, unattended by the male, descending here and there to strike the surface and liberate eggs, making but one or two dips in a place, and flying some distance before descending again. The nymphs transform at the very edge of the water, seldom crawling more than an inch or two above the surface of it. Moss-grown logs in the edges of Little Clear pond were in many 4S6 NEW YORK STATE MUSEUM places piled several layers deep with the exuviae of this species, inter- mixed with a lesser number ofG. spicatus skins. Nymph. Total length 26 mm; abdomen 18 mm; hind femur 5.5 mm; width of head 5 mm, of abdomen 6 mm. Abdomen depressed, lanceolate, regularly narrowed beyond the sixth segment to a rather pointed apex; the loth segment two thirds as long as the eighth, a little less than half as long as the ninth ; lateral spines on segments 6-9, very minute, specially on segment 6, increasing in size posteriorly, on segment 9 one half as long as segment 10 : dorsal hooks low and obscure, but pointed on sixth to ninth segments. Labium with its median lobe a very Httle convex on the front margin, and sometimes with an imperfect median tooth ; lateral lobe considera- bly arcuate, with a strong end hook, and with 4-7 very variable teeth on its inner margin, each tooth obliquely truncate, with the longer angle directed to the rear. This species and G. sordidus, offer an easy transition to the Arigomphus group, below. Gomphus ventricosus Walsh 1863 Gomphus ventricosus Walsh. Ent. soc. Phil. Proc. 2 : 249 1875 Gomphus ventricosus Hagen, Bost. soc. nat. hist. Proc. 18:47 (listed) 1900 Gomphus ventricosus Williamson, Dragon flies Incl. p. 287 (de- scription and figure) This apparently rare species has not yet been taken in New York. I include it in this list because of its occurrence in Illinois and Massachu- setts; it will doubtless yet be found within the state. Its nymph is unknown. , Gomphus amnicola Walsh 1862 Gomphus amuicola Walsh, Acad. nat. sci. Phil. Proc. p. 396 1863 Gomphus amnicola Walsh, Ent. soc. Phil. Proc. 2 : 256 (note) 1897 Gomphus amnicola Calvert, N. Y. ent. soc. Jour. 5 : 95 (listed from Bethlehem N. Y.) 1900 Gomphus amnicola Williamson, Dragon flies Ind. p. 294 (descrip- tion and figure) Another species which is apparently rare, once collected within the state by Dr Lintner at Bethlehem. The nymph is unknown. Gomphus scudderi Selys 1878 Gomphus scudderi Selys, Acad. Belg. (2) Bui. 46 : 460 $ 1898 Gomphus scudderi Harvey, Ent. news, 9 : 62-63 5 (description and figures) This handsome black species (pi. 17, fig. 2), unique in the yellow basal rings on its abdominal segments, has not been reported hitherto AQUATIC INSECTS IN THE ADIRONDACKS 457 from this state. It was common at Saranac Inn, and even more common, judging by the numbers of exuviae in evidence along the bank, at Axton along Stony brook. But few images were seen at large, but many were bred from nymphs taken from Little Clear creek beside the hatchery. This species, unlike most Odonata, seems to prefer daylight, and even midday as a time for transformation. The boarded banks of the im- pounded creek beside the hatchery were watched through the entire season, and each day the exuviae left there were gathered. Rarely were any fresh skins found there early in the morning. July was so rainy there was comparatively Httle time suitable for transformation; and, when the clouds would break away about noon and the sun shine out, I could be sure, on going out, to find some nymphs in transformation. On the few clear days, this was most often observed about noon. All the skins observed were left 3-30 inches above the surface of the water. The nymphs are rather slow and sprawHng. The images seem to spend little time in flight, preferring to rest on timbers about the rapids of the stream. Nymph. (PI. i8, fig. 2) Measures in total length 42 mm ; abdomen 28 mm; hind femur 5.2 mm; width of head 6.3 mm, of abdomen 8 mm. Body elongate, depressed, with the long abdomen regularly tapering for half its length ; the fringe of hairs on lateral margins very dense and soft; color yellowish brown, darker on the sides of the thorax; eyes black; ocelh yellowish; a double row of trapezoidal blackish spots on the abdomen between the middorsal line and the line of scars each side, each spot with a prolonged external apical angle reaching the apical carina on each segment, the spots on segments 9 and 10 becoming diffused over the sides of the segments ; a series of minute, longitudinal yellowish dashes in the apical sutural area of each segment. That so much of color pattern is observable is doubtless due to the fact that these nymphs live in comparatively clean sand. Abdomen depressed, and with a well marked middorsal impressed line, and no dorsal hooks, save the merest rudiment on the apex of the ninth segment ; lateral spines well developed on segments 6-9 (there are tufts of hairs on the latter apical angles of segments before the sixth) in- creasing a little in size posteriorly, those of the ninth segment closely appressed, and hardly surpassing the base of the tenth segment. Mentum of labium a third longer than Avide ; front border of median lobe nearly straight, with a sparse fringe of flattened scale Hke hairs; lateral lobe strongly incurved at about a right angle beyond the base of the movable hook; about four teeth on the inner margin, increasing a little in size posteriorly. While nymphs of several sizes were taken together in the creek, they seemed to have a definite period, including hardly more than the month of July, for transforming. Aug. 2 was the date of the first imago captured at large. June 30 was the date of the first imago bred. 458 NEW YORK STATE MUSEUM GoiTxphus vastus Walsh 1862 Gomphus vastus Walsh, Acad. nat. sci. Phil. Proe. p. 391 1875 Gomphus vastus Hagen, Bost. soc, nat. hist. Proe. 18 : 47 (listed from New York) 1872 Gomphus vastus Cabot, Mus. compar. zool. Mem. v. 3, pi. 2, fig. 4 (description and figure of nymph) 1885 Gomphus vastus Hagen, Am. ent. soc. Trans. 12 ; 265-66 (description of nymph) 1890 Aeshna vasta Kirby, Cat. Neur. Odon. p. 66 (listed) 1892 Gomphus vastus Banks, Am. ent. soc. Trans. 19 : 352 (listed) 1893 Gomphus vastus Calvert, Am. ent. soc. Trans. 20 : 245 (description) 1895 Gomphus vastus Calvert, N. Y. ent. soe. Jour. 3 : 45 (listed from New York) 1899 Gomphus vastus Kellicott, Odon. Ohio, p. 57-58 (description and figure) 1900 Gomphus vastus Williamson, Dragon flies lud. p. 287 (description and figure) This striking species frequents the shores of the Great lakes and the larger streams. The nymphs hve on the bottom at some depth. In the above bibliography are indicated numerous descriptions and some figures of both nymph and adult. The species may be recognized by the characters stated in the tables. Gomphus plagiatus Selys 1854 Gomphus plagiatus Selys, Acad. Belg. (2) Bal. 21 : 57 1861 Gomphus plagiatus Hageu, Synopsis Neur. N. Am. p. 109 1885 Gomphus plagiatus Hagen, Am. ent. soc. Trans. 12:269-70 (de- scription of the nymph) 1893 Gomphus plagiatus Calvert, Am. ent. soe. Trans. 20 ; 244 (descrip- tion) 1897 Gomphus p 1 a g i a t u.s Calvert, N. Y. ent. soc. Jour. 5 : 95 (listed from New York) 1899 Gomphus plagiatus Kellicott, Odou. Ohio, p. 69-70 (description and discussion) 1900 Gomphus plagiatus Williamson, Dragon fiies Ind. p. 295-96 (descrip- tion and figure) A very large species, apparently commonest about broad marshy tracts, taken but once as yet in this state. It will be easily recognized by the characters stated in the tables. Gomphus spiniceps Walsh 1862 ?Macrogo mphus spiniceps Walsh, , Acad. nat. sci. Phil. Proe. p. 389 1854 Gomphus spiniceps Selys, Acad. Belg. (2) Bal. 21 : 57 AQUATIC INSECTS IN THE ADIRONDACKS 459 1885 Gomphus spiaieeps Hageu, Am. ent. soc. Trans. 12 : 270-71 (de- scription of nymph) 1899 Gomplius spiniceps Kellicott, Odon. Ohio, p. 69 (description and figure) 1900 Gomphus spiniceps Williamson, Dragon flies Ind. p. 295 (descrip- tion and figure) A strong flying species, frequenting rapid streams. Transforms in mid- summer, and appears in flight and ovipositing late in the summer or early in autumn. " Observed flying late in the afternoon, and oviposit- ing in a small brook that was rippling over pebbles." KeUicott {Joe. cit.) The species has not been recorded from this state hitherto, but there are New York specimens in the Museum of comparative zoology, and the species has long been known from Illinois and Massachusetts. Gomphus spicatus Hagen 1854 Gomphus spicatus Hagen, Acad. Belg. (2) Bui. 21 : 54 1861 Gomphus spicatus Hagen, Synopsis Neur. N. Am. p. 107 1875 Gomphus spicatus Hagen, Bost. soc. nat. hist. Proc. 18 : 47 (listed ; distribution given) 1890 Aeshna spicata Kirby, Cat. Neur. Odon. p. 64 (listed : bibliography) 1892 Gomphus spicatus Banks, Am. ent. soc. Trans. 19 : 353 (listed) 1895 Gomphus spicatus Calvert, N. Y. ent. soc. Jour. 3 : 45 (listed) 1897 Gomphus spicatus Van Duzee, N. Y. ent. soc. Jour. 5 : 89 (listed from Clarence) 1897 Gomphus spicatus Calvert, N. Y. ent. soc. Jour. 5 : 93 (listed from Clarence) 1899 Gomphus spicatus Kellicott, Odon. Ohio, p. 97-98 (description and figure) 1900 Gomphus spicatus Williamson, Dragon flies Ind. p. 292 (description and figure) This is a common species in the northeastern United States, ranging from Illinois eastward ; it is more generally distributed throughout its range than are most gomphines. Next to G. exilis it was the com- monest Gomphus at Saranac Inn, where it frequented all sorts of waters. Imagos were common during the latter part of June and the first two weeks of July along the wagon road and railroad between Little Clear and Big Clear creeks ; they were foraging there, and, while a little shy and wary, were not very difficult to catch with a net. Nymph. Total length 31 mm ; abdomen 20 mm ; hind femur 6.2 mm ; width of head 5 mm, of abdomen 7 mm. Body elongate, somewhat depressed; abdomen lanceolate, pointed. Color dark brownish, with some black marks on the sides of the thorax ; margins of the abdominal segments darker ; a pair of black dots on the dorsum of each of the middle abdominal segments. 460 NEW YORK STATE MUSEUM Dorsal hooks of abdomen represented only by minute backward pro- longations of the median ridge on all the segments; lateral spines on segments 7-9, increasing in size posteriorly, small, on the ninth segment much shorter than the loth segment, against which they are closely ap- pressed; loth segment two thirds as long as the eighth, and a httle less than half as long as the ninth. Labium with its median lobe distinctly convex anteriorly, and with a brown tooth in the middle in the midst of the usual flat, fringing hairs ; lateral lobe regularly arcuate, with about nine coarse, trapezoidal, ser- rately recurved teeth on its inner margin. A goodly number of specimens of the nymphs were collected from Little Clear creek on the hatchery grounds, Little Clear pond near its outlet, and from Bone pond. Gomphus villosipes Selys 1854 Gomphus villosipes Selys, Acad. Belg. (2) Bui. 21 : 53 1861 Gomphus villosipes Hagen, Synopsis Neur. N. Am. p. 105 1890 Aeshna villosipes Kirby, Cat. Neur. Odon. p. 64 (bibliography) 1893 Gomphus villosipes Calverfc, Am. ent. soc. Trans. 20 : 244-45 (de- scription) 1894 Gomphus villosipes Banks, Can. ent. 26: 77 (listed from Ithaca) 1895 Gomphus villosipes Calvert, N. Y. ent. soc. Jour. 3 :45 (listed from Ithaca) 1897 Gomphus villosipes Van Duzee, N. Y. ent. soc. Jour. 5 ; 89 (listed from Grand Island) 1897 Gomphus villosipes Calvert, N. Y. ent. soc. Jour. 5 : 93 (listed from Grand Island) 1897 Gomphus villosipes Needham, Can. ent. 29: 166 (note on rearing the nymph at Ithaca) 1899 Gomphus villosipes Kellicott, Odon. Ohio, p. 63 (description and figure) 1900 Gomphus villosipes Williamson, Dragon flies Ind. p. 291 This is an exceedingly common species at Ithaca, where I have picked up thousands of the exuviae at a time along the borders of the Cascade pond in June. The imagos fly about or rest on the snags and pro- jecting rocks, which are common in the turbulent creeks about Ithaca. The nymphs burrow in the bottom in shallow water, seeming to prefer banks of somewhat clayey mud. They are slow moving, stiffly sprawl- ing creatures, powerful, rapacious, and seemingly the dominant animals in the bottom mire. Nymph. Total length 35 mm; abdomen 23 mm; hind femur 7.5 mm; width of head 6 mm, of abdomen 8.5 mm. Body depressed, with legs wide apart and very sprawhng ; abdomen lanceolate, pointed, rapidly narrowed beyond the fifth to the base of the ninth segment, more slowly narrowed thereafter. The whole body and all appendages, clothed with a dense scurfy pubescence, which is con- spicuously marked with bare lines or "scars." AQUATIC INSECTS IN THE ADIRONDACKS 461 Abdomen with obtuse, continuous middorsal ridge, showing no trace of dorsal hooks ; lateral spines very small, closely appressed, and incon- spicuous, present only on segments 8 and 9, on 8 very short, on 9 longer, but closely applied to the sides of segment 10. The loth segment is hardly shorter than the eighth, but it is less than half as long as the ninth. The mentum of the labium is distinctly produced and rounded on its front border, with a median brown tooth in the midst of the fringing flat hairs. The lateral lobe is broad and strongly arched, with about six coarsely serrate teeth on its inner margin. Gomphus furcifer Hagen 1878 Gomphus furcifer Hagen, Acad. Belg. (2) Bui. 46 : 458 1899 Gomphus furcifer Kellicott, Odon. Ohio, p. 64 (description and figure) 1900 Gomphus furcifer Williamson, Dragon flies Ind. p. 292 (description and figure) This species has not hitherto been recorded from New York state, and I have not seen it there at large ; but there is a specimen bearing an Ithaca label in the Cornell university collection. The nymph is unknown. DROMOGOMPHUS A single species of this genus belongs to the New York fauna. Dromogomphus spinosus Selys 1854 Gomphus spinosus Selys, Acad. Belg. (2) Bui. 21:59 1861 Gomphus spinosus Hagen, Synopsis Neur. N. Am. p. 102 1862 Gomphus spinosus Walsh, Acad. nat. sci. Phil. Proc. p. 391 (note) 1863 Gomphus spinosus Hagen, Stett. ent. zeit. 24 : 37.3 1873 Gomphus spinosus Hagen, Bost. soc. nat. hist. Proc. 16 : 359 1875 Gomphus spinosus Hagen, Bost. soc. nat. hist. Proc. 18 : 44 (bibli- ography) 1893 Dromogoraphus spinosus Calvert, Am. ent. soc. Trans. 20:245 (description) 1894 Dr o mogo mp h us s p in o s u s Banks, Can. ent. 26:77 (listed from Ithaca and Baldwinsville) 1895 Dromogomphus spinosus Calvert, N. Y. ent. soc. Jour. 3:45 (listed from Ithaca and Baldwinsville) 1897 Dr 0 m o go mp h u s spinosus Calvert, N. Y. ent. soc. Jour. 5:93 (listed from Earner) 1897 Dromogomphus spinosus Needham, Can. ent. 29 : 186 (characters of the nymph) 1899 Dromogomphus spinosus Kellicott, Odon. Ohio, p. 71 (description) 1900 D r o m o go m p h u s s p i n 0 s u s Williamson, Dragon flies Ind. p. 296 (description) This species has been taken sparingly and in a few places within the state, but it is probable that it frequents the borders of most of the larger 462 NEW YORK STATE MUSEUM bodies of water. Prof. Herrick of the Agricultural college of Mississippi found it transforming abundantly on the shore of Canandaigua lake at the natural science camp in June 1897. I have found it at Ithaca and at Saranac Inn; at the latter place only in Little Clear pond, near the outlet. That was during the week which included June 30. The nymphs were crawling up out of rather deep water on stumps and logs on the bank to transform. A big pine stump that stood partly in the water, halfway between the outlet and the cold water pipe, seemed a favorite place of transformation. It was fairly dotted over with exuviae, most of which were several feet above the water. No imagos were seen, excepting the few that were bred. Nymph. (PI. 18, fig. i) Total length ^^ mm; abdomen 22 mm; hind femur 7 mm; width of head 6 mm, of abdomen 7 mm. Body elongate, little depressed, little hairy; color dirty brownish, becoming clear brown on the apex of the abdomen ; some darker mark- ings on the sides of the thorax and at the lateral margins of the abdo- men, and across the base of the dorsum of the middle abdominal segments. Head cordate in outline, the hind margin being broadly emarginate ; antennae long, considerably surpassing the tip of the labrum, and upturned beyond the end of it; first segment twice as large as the second, both globular ; third segment narrowly cylindric, more than twice as long as the two basal ones together, bearing the minute, rudimentary, globular, fourth segment on its upturned tip ; burrowing hooks well developed. Abdomen narrowed beyond the sixth segment rather regularly ; dorsal hook on segments 2-9 regularly increasing in size and sharpness, and regularly increasingly declined posteriorly, that on segment 9 being a direct continuation of the sharp middorsal ridge of the segment, black tipped, lateral spines on segments 6-9 increasing in size posteriorly, those of the ninth segment reaching the level of the middle of the loth seg- ment; the eighth segment is a third longer than the loth; the ninth segment is two and one half times as long as the loth; the superior and inferior appendages are somewhat longer than the loth segment, but the laterals are about equal to it, being about one fourth shorter than the other appendages. The mentum of the labium is rather regularly widened anteriorly, with a straight front border; lateral lobes strongly arcuate, with end hook distinctly more prominent than the nine or ten coarse, angulately serrate teeth before it on the inner margin. Subfamily aeschninae This group includes the largest, fleetest, and most voracious of our dragon flies. Many of them are common and very well known. Most of the species are marked with bright blues and greens. They roam far from water, and often find their way into houses in warm weather. Several species are commonly seen coursing over lawns in the evening twilight. AQUATIC INSECTS IN THE ADIRONDACKS 463 The nymphs are known for a larger proportion of the genera than in any other subfamily. They are climbers among green plants, over tim- bers, on swaying roots, etc., preferring the border of open water or the edge of a current. They are slender, active, clean, with smooth bodies marked with a color pattern of greens and browns, well adapted to con- cealment in the midst of their natural environment. They will eat al- most any living animal that they can capture and hold, and they eat one another with evident relish. The nymphs agree in the possession of the following characters : Head depressed; antennae (when grown) six to seven-jointed, filiform ; eyes large, very prominent, covering the anterolateral angles of the head ; labium very long, reaching between the bases of the middle legs, men- tum flat, not covering the face, median lobe with a minute median cleft, lateral lobe denticulate on inner side, and with a terminal hook, as well as the usual movable hook ; legs slender, fitted for climbing and cling- ing; tarsi three-jointed; prothorax with a transverse, dorsal, flattened area, and a pair of conic processes above each coxa; spiracles large, conspicuous ; abdomen somewhat spindle-shaped, with lateral margins becoming acute posteriorly; lateral spines present on a variable number of the segments ; inferior abdominal appendages at least twice as long as the lateral appendages. The following tables will enable any one to distinguish the members of our few genera. KEY TO GENERA Imagos a The radial sector (Es., fig. 9) simple \) But two cubito-ana] cross veins ; vein M2 undulate ; supratriangle with- out cross veins ; but one cross vein under the stigma..Gom p haeschna 6& With three or more eubito-anal cross veins ; vein Ms not undulate ; supra- triangle divided by cross veins ; several cross veins under the stigma c Basal space traversed by cross veins Boyeria CO Basal space open , Basiaeschna aa Eadial sector bearing an apical fork 6 Sectors of the arculus (veins M1-3 and M4 ) separating from the arculus at or below its middle c The radial sector symmetrically forked, between it and the supplementary vein below it, one or two rows of cells d Face strongly produced above, the upper margin of the frons very acute ; the veins Mi and M3 parallel to the level of the stigma ; radial sector and the supplementary vein below it separated by a single row of cells Nasiaeschna dS, Face vertical, not sharply angulate at upper edge of frons ; veins Mi and M2 approximated at the stigma ; the radial sector and the supple- mentary vein below it separated by two rows of cells Epiaeschua cc The radial sector strongly deflected toward the stigma at the base of its fork, unsymmetric; between it and the supplementary vein below it, three to seven rows of cells Aeschna && Sectors of the arculus springing from above the middle of the arculus. An ax 464 NEW YORK STATE MUSEUM Nymphs These are known for all the foregoing genera except G o m p h - aeschna: the nymphs figured and described by Cabot and referred by supposition to that genus, were the males of Boyeria (see below under the account of that genus) . Among all our nymphs that are still unknown, that of Gomphaeschna remains one of the most de- sirable discoveries yet to be made. a Hind angles of the head viewed from above, sharply angulate & Lateral lobe of labium squarely truncate on apex Boyeria Z>& Lateral lobe of labium with taper-pointed apex Basiaeschna aa Hind angles of the head obtusely rounded fe With lateral spines on abdominal segments 4-, 5-, or 6-9. c With lateral spines on segments 4-, or 5-9 d With dorsal hooks on abdominal segments 7-9 Nasiaeschna dd With no dorsal hooks on abdomen Epiaeschna CG With lateral spines on abdominal segments 6-9 Aeschna lib With, lateral spines on abdominal segments 7-9 Anas So well marked are these genera that their nymphs may be recognized by the following Single distinctive characters Nasiaeschna alone has dorsal hooks on the abdomen. Basiaeschna alone has the apices of its lateral labial lobes pointed. A n a X alone has lateral spines on abdominal segments 7-9 only. Aeschna alone has lateral spines on abdominal segments 6-9 only. Boyeria alone has two teeth on the front border of the median lobe of the labium, at a distance either side from the median cleft. Epiaeschna alone is lacking in all the above characters. GOMPHAESCHNA The single regional species G. furcillata Say has not been taken as yet within this state, so far as records show. Its nymph is unknown, that one referred to this species by Cabot on supposition proving to be the male nymph of Boyeria, described below. BOYERIA This genus includes the single North American species. Boyeria vinosa Say 1839 Aeschna vinosa Say, Acad. nat. sci. Phil. Jour. 8 : 13 1839 Aeschna 4-guttata Burmeister, Handb. ent. 2 : 837 1861 Aeschna 4-guttata Hagen, Synopsis Neur. N. Am. p. 130 1875 Neuraeschna vinosa Hagen, Bost. soc. nat. hist, Proc. 18:37 (full bibliography and distribution) AQUATIC INSECTS IN THE ADIRONDACKS 465 1892 Aeschna vinosa Banks, Am. ent. soc. Traus. 19:353 (listed from New York) 1893 Fon scolombia vinosa Calvert, Am. ent. soc. Trans. 20:247 (de- scription) 1895-97 Fon scolombia vinosa Calvert, N. Y. ent. soc. Jour. 3 : 45 and 5 : 93 (listed from Keeseville, Ithaca, Schoharie, Piseco lake, Elk lake, Colden, and Westchester co.) 1899 Fon scolombia vinosa Keliicott, Odon. Ohio, p. 90 (description) 1900 Boyeria vinosa Williamson, Dragon flies Ind. p. 300-1 (description) 1881 Neurae schn a vinosa Cabot, (Nymph) Mus. compar. zool. Mem. 8 : 29, 39, pi. 2, fig. 3 This interesting species, which seems likely to be found inhabiting almost every woodland creek in the state, was very common at Saranac Inn in Little Clear creek, and in the borders of the pond above. The nymphs were transforming commonly on the sides of timbers in the edge of the water from the beginning of our session till the latter end of July. A number of both sexes were reared in our cages. A few images might be seen, specially afternoons in favorable weather from midsummer till the end of our session, about the creek on the hatchery grounds. They glide along above the stream, not vety rapidly, on well poised, transpar- ent wings, which against the background of the water are well nigh in- visible. The two big round yellow spots on each side of the thorax dis- tinguish this species from all its kin, even while in flight. The nymphs, which are generally quite dark colored, seem to prefer timbers, trailing roots, driftwood, etc., as a foraging ground. I have rarely taken them from green vegetation. Nymph. Total length $ 33, $36 mm; abdomen, $ 22.5, $25mm; hind femur 5.5 mm; width of head 7 mm, of abdomen 7.5 mm. Body elongate, slender, smooth; color blackish brown, obscurely marked with paler in transverse rings on the legs, and in dashes, tending to become arranged in interrupted, longitudinal rows on the abdomen. Head concave behind, with truncated hind angles; sides straight, diverging strongly anteriorly to meet the very prominent eyes ; labium moderate ; middle third of front margin of median lobe straight, with a tooth at each side remote from the median cleft. Abdomen widest across the fifth and sixth segments, tapering unequally to the ends ; no dorsal hooks ; lateral spines on segments 5-9, on 5 small, on 6-9 conspicuous, increasing a little in size posteriorly, those of the ninth segment three fourths as long as the loth segment; the ab- dominal segments are longest in the middle, and decrease a little toward both ends ; the appendages are longer than the last two segments together, and differ in the two sexes in the form of the apex of the super- ior appendage; in the $ this has a distinct narrow apical cleft, in the ? the cleft is closed when grown ; in small female nymphs, however, I have seen it quite as widely open and as distinct as in the male : in both sexes 466 NEW YORK STATE MUSEUM the laterals are one fourth as long, and the superiors eight ninths as long as the inferiors. Some smaller nymphs from the creek show a middorsal black band on the abdomen, divided by a median row of small yellow spots, largest on the eighth segment. Basiaeschna Janata Say 1839 Aeschna Janata Say, Acad. nat. sci. Phil. Jour. 8 : 13 1842 Aeschna minor Eambur^ Ins. Neur. p. 207 1861 Aeschna Janata Hagen, Synopsis Neur. N. Am. p. 125 1875 Aeschna Janata Hagen, Bost. soc. nat. hist. Proc. 18 : 33 (full bibli- ography and distribution) 1895 Basiaeschna Janata Calvert, N. Y. ent. soc. Jour. 3 : 45 (listed from Keeseville) 1899 Basiaeschna Janata Kellicott, Odon. Ohio, p. 81 (description) 1900 Basiaeschna Janata Williamson, Dragon flies Ind. p. 301 (descrip- tion) This species is perhaps the earliest of the Aeschninae. It was common about the hatchery grounds on our arrival, and had about dis- appeared by midsummer. I got mostly immature nymphs at Saranac Inn, but I bred the species abundantly at Ithaca several years ago. I saw females ovipositing several times during the first week of our stay at Saranac Inn, and watched the process once in detail. In each instance observed the eggs were deposited in leaves of a species of bur- reed, Sparganium, which, where it grew in the deeper water of the creek, trailed its long leaves on the surface of the stream. The female flitted from plant to plant, making a few thrusts with her ovipositor into each at the water line, and then settled and balanced herself carefully on a long, floating leaf; this was doubtless a most favorable place for the eggs, and she settled down to more extensive operations. Backing down into the water till the abdomen was wholly submerged, she began thrusting with her ovipositor, first to right and then to left, moving for- ward a little between thrusts, leaving behind a double row of egg punc- tures, as regular as the neatest double stitching that might be done with a needle. Several such double rows of eggs were placed in the tissues of this leaf before she left it. The leaf was found to be thickly covered on the under side (as all submerged surfaces were covered in the creek at that time) with hundreds of red hydras, in all stages of budding. I placed the leaf in a hatchery trough, where the hydras remained in good condition till after the hatching of the eggs. Nymph. Total length 43 mm; abdomen 30 mm; hind femur 6 mm; width of head 7.5 mm; of abdomen 8 mm. Body elongate, slender, nearly smooth ; color brownish black, with paler rings on the femora and tibiae, three or four rings on each ; pale AQUATIC INSECTS IN THE ADIRONDACKS 467 marks on the lateral margins of the abdominal segments at base ; a broad middorsal pale band on abdomen, motded with brown, and including two blackish spots on the eighth segment; appendages, spines, tarsal seg- ments and claws, yellow, blacktipped. Head with very prominent, anteriorly directed eyes, narrowed behind the eyes to very sharp hind angles ; between these angles the rear of the head is slightly concave ; the labium has its median lobe prominent, fringed, distinctly cleft; the lateral lobe, rather small, tapering to its incurved apex, rather regularly. Abdomen without dorsal hooks, with lateral spines on segments 3 or 4-9, increasing in size posteriorly, those of the ninth segment about equal- ing in length the loth segment; inferior appendages long and very sharp, distinctly longer than the last two abdominal segments; superior one half to three fifths as long as the inferiors, its apex with a round notch; later- als about half as long as the superior. The unusual brevity of the superior appendage is about as distinctive as the shape of the lateral labial lobe, indicated in the above table. NASIAESCHNA^ There is a single species. Nasiaeschna pentacantha Rambur 1842 Aeschna pentacantha Eambur, Ids. Neur. p. 208 1861 Aeschna pentacantha Hagen, Synopsis Nenr. N. Am. p. 129 (de- scription) 1862 Aeschna pentacantha Walsh, Acad. nat. sci. Phil. p. 397 (notes) 1875 Aeschna pentacantha Hagen, Bost. soc. nat. hist. Proc. 18 : 37 (bibliography and distribntion) 1888 Epi aeschna heros (nyinph) Garman, 111. state lab. nat. hist. Bui. 3 : 178 (descriptive notes) 1895 Aeschna pentacantha Banks, Ent. news, 6:124 (recorded from Baldwinsville) 1897 Aeschna pentacantha Calvert, N. Y. ent. soc. Jour. 5:95 (recorded from Baldwinsville) 1900 Aeschna pentacantha Williamson, Dragon flies Ind. p. 305 (descrip- tion) This species ranges from Massachusetts to Texas, and from lUinois to Georgia : it is apparently rare throughout its range. Probably not more than a dozen specimens of the adult insect exist in collections. As to the nymph, Garman first found it in the Mississippi bottoms near Quincy 111. His types were lent me for study several years ago by Prof. Forbes. I was able to refer them by exclusion to this species. Mr Hart of the Illinois state laboratory, has since written me that he has suc- cessfully reared similar nymphs obtained by him in a creek near Cham- paign 111. Thus their identity is settled. I have since obtained well 1 de Selys 1900: diagnosis in French, included in a paper "Odonaten aus Neu-Guinea" by F. Forster, In Termeszetrajzi Filzetek, v. 23 (Budapest). 468 NEW YORK STATE MUSEUM grown nymphs from Moline 111. Two images taken by Prof. R. H. Pettit at Baldwinsville, Onondaga co., constitute the only record of the species for this state. Nymph. (The largest I have before me, not grown^ as shown by the shortness of the wing cases.) Measures 24 mm; abdomen 16 mm; hind femur 4 mm; width of head 5.5 mm, of abdomen 6 mm. Color blackish, labium and tarsi yellowish ; body rough granulate, but not hairy, with paired tubercles obtuse above the base of the antennae, and on the middle of the vertex, and on the middle of the superolateral ridge that extends from the rear of the eyes to the hind angles of the head; a pair also on the superolateral angles of the prothorax; and the usual two pairs above the bases of the coxae, the anterior a little longer and stouter, but both directed anteriorly ; three or four pairs above the middle and hind coxae, running down into a ridge which extends on these coxae; a dorsal, tuberculate, superior ridge on all the femora; dorsal hooks represented on all the segments of the abdomen, becoming prominent and pointed on segments 6-9; lateral spines on segments 5-9, increasing in length posteriorly, those of the ninth segment, two thirds as long as the loth segment; appendages more than twice as long as the loth segment, superior and inferiors of equal length, laterals one fourth to one fifth as long as the others, superior, obtuse at tip, inferiors finely denticulate exteriorly. Head considerably narrowed behind the eyes, and with a deep, quad- rangular excavation of the hind margin ; eyes with a very long anterior border, and a long pointed hind angle lying on the vertex; labium with the cleft of the median lobe somewhat v-shaped, not closed; lateral lobe truncate on apex, with about 18 denticles on inner margin. EPIAESCHNA There is a single North American species. Epiaeschna heros Fabricius 1798Ae8hna heros Fabricius, Ent. syst. Suppl. j). 285 1839 Aeshna multicincta Say, Acad. nat. sci. Phil. Jour. 8:9 1861Aeschna heros Hageu, Synopsis Neur. N. Am. p. 128 1869Aeschua heros Harris, Ent. correspondence, p. 326 (notes) 1862Ae8chna heros Walsh, Acad. nat. sci. Phil. Proc. p. 397 (notes) 1875 Aeschna heros Hagen, Bost. soc. nat. hist. Proc. 18:36 (bibliography and distribution) 1881 Epiaeschna heros (nymph) Cabot, Mus. comp. zool., Mem. 8:30, 39, pi. 1, fig. 3 1893 Epiaeschna heros Calvert, Am. ent. soc. Trans. 20 : 246-47 (de- scription) 1895-97 Epiaeschna heros Calvert, N. Y. ent. soc. Jour. 345 ; 5 : 93 (listed from Dobbs Ferry, New York, Itbaca, Albany and Buffalo) 1899 Epiaeschna heros Kellieott, Odon. Ohio, p. 81 (description) 1900 Epiaeschna heros Williamson, Dragou flies Ind. p. 302 (descrip- tion) This, our largest dragon fly, is widely distributed throughout the state, and, for that matter, throughout the whole eastern United States. Its AQUATIC INSECTS IN THE ADIRONDACKS 469 Strikingly large size, and its habit of flying into houses not unfrequently, and its apparent migrations in numbers, have made it a rather well known species. Since the nymph has been described and figured by Cabot, it will suf- fice here to give a brief statement of its more distinctive characters. Nymph. Apparently full grown, measures in total length 46 mm ; abdomen 32 mm ; hind femur 7.5 mm ; width of head 10 mm, of abdomen 10 mm. Body very elongate, widest across the eyes and the seventh and eighth ab- dominal segments. Head flat, much narrowed behind the eyes, with a deep, well rounded concavity on the hind mar- gin, and obtuse hind angles ; labium long extending posteriorly between the bases of the middle legs; mentum (fig. 13) with sides parallel for half its length, then suddenly widened in a regu- lar curve to the bases of the lateral lobes; median lobe with convex front border divided by a shallow open cleft, bearing a fringe of short scales on either side of the cleft ; lateral lobe truncate on tip with a short hook on inner angle at tip, before which are some 12 to 15 denticles. Abdomen with an obtuse middorsal ridge ; lateral spines on segments 5-9, increasing in size posteriorly, on 9 hardly Fa^tJf;. from^^^tmn' fifo'to by j^'S. Neelham longer than half of the length of the loth segment, but broadly triangular; superior appendage almost as long as the inferiors, not cleft at apex ; laterals half as long, inferiors not quite as long as segments 9 and 10 together. ABSCHNA Three closely related species of this genus are known from the state. Male imagos of these species may be separated by the following key. KEY TO SPECIES OF AESCHNA a Anal triangle of hind wing of male consisting usually of three cells. Superior abdominal appendages of male with a prominent inferior spine at the distal end ; genital valve of female strongly elevated at the apex .. constricta aa Anal triangle of the hind wing of the male consisting generally of two cells; sui^erior appendage of the male without prominent inferior spine; genital valve of female not strongly elevated at its ajiex & Superior abdominal appendages of the male with a superior longitudinal carina denticulated clepsydra hi Superior appendages of the male with the superior longitudinal carina not denticulated verticalis 470 NEW YORK STATE MUSEUM I am not able to distinguish between the nymphs of these species. Constricta and clepsydra were both common at Saranac Inn during the latter half of the summer. I collected many nymphs, and it would seem likely that I should have both species; but I have found hitherto no specific differences between them. The images of the three species are similar in habits and are often found flying together. It is probable that the nymphs are likewise similar in habits. The nymph of Aeschna constricta is described and figured by Cabot^ . Descrip- tions of these three species will be found in the monographs of Calvert, Kellicott and Williamson, frequently cited in the preceding bibliographies of species. Under these circumstances it seems unnecessary to enter into a detailed discussion of them. It will suffice, for the certain recog- nition of nymphs of the genus, to restate the chief characters of the nymph of A. constricta, a species which I have bred abundantly at Ithaca and at Saranac Inn. Nymph. Fully grown measures in total length 43 mm, abdomen 31 mm, hind femur 6.5 mm ; width of head 7.5 mm, of abdomen 7.5 mm. Body elongate, graceful, active ; color varied green and brown, the amount of either color varying to agree with environment, the paler markings of the dorsum generally tending to form longitudinal inter- rupted streaks. Head with prominent, well-rounded eyes, whose hind angles almost meet on the vertex ; rear of head hardly convex posteriorly ; hind angles broadly rounded ; labium moderately widened in distal half of mentum ; middle lobe with closed median cleft ; lateral lobe squarely truncate on end, denticulate within. Abdomen widest in the middle, where the segments are also longest ; lateral spines on segments 6-9, on 6 minute, on 9 a little longer than half the length of the loth segment; inferior appendages longer than segments 9 and 10; the deeply notched superior appendage three fourths as long as the inferiors, the laterals one half as long as the inferiors and with very sharp, incurvate points. ANAX The single species discussed below properly belongs to our fauna: another tropical species, Anax longipes is occasionally picked up on our Atlantic coast. 1773 Libellula junia Drury, Illus. exotic eut. v. 1, pi. 47, fig. 5n 1842 Aeschna spiniferus Rambur, Ins. Neur. p. 186, pi. 1, fio;. 14 1854 Emmous, Agric. N. Y. v. 5, pi. 15, fig. 3 (colored figure of the male; no description ; no name) 1861 Anax Junius Hagen, Synopsis Neur. N. Am. p. 118 1875 Anax Junius Hagen, Bost, soc. nat. hist. Proc. 18 : 32 (full bibliography and distribution) ^ Immature state of the Odonata. 1881. pt 2. AQUATIC INSECTS IN THE ADIRONDACKS 471 1890 Anas Junius Hagen, Psyche, 5 : 305 (critical account of tlie species) 1893 Anax jnnivis Calvert, Am. ent. soc. Trans. 20 : 249 (description) 1897 Anax Junius Calvert, N. Y. eut. soc. Jour. 3 : 46 and 5 : 93 (listed from New York, Ithaca, Schoharie and Buffalo) 1899 Anax Junius Kellicott, Odon. Ohio, p. 77 1900 Anax Junius Williamson, Dragon flies Ind. p. 306 1881 Anax Junius Cabot, (nymph) Mus. comp. zool. Mem. 8 : 15, 36, pi. 1, fig. 2 Anax Junius Drury This well known species, which is very common in most parts of the state, was rather rare at Saranac Inn. A single nymph was taken from the little bog pond on the inn wagon road, and a single male imago was observed fly- ing over the same pond. Elsewhere the imagos are on the wing from March till November; they fly from daylight to dark, and are fleet, powerful and fearless. The female in ovipositing is often held by the male, specially in early spring, often is unattended, and sometimes de- scends bodily into the water. In early spring the eggs are inserted in the water- soaked stems of reeds, in floating sticks, etc. ; later in the season they are placed in the tissues of green and growing aquatic plants. Fig. 14 Early stages of nymph of Anax rr-ii 1 r ^ • • • --111 Junius Dru., showing changes of color Ihe nymph or this species is probably pattern a, newly hatched : B, one fourth grown ; (J, one half grown better known than that of any other. It is sure to get into the net of the aquatic collector. It clings to water weeds nearer the surface, usually, than the bottom, in an atti- tude of alertness, with head poised low and abdomen slightly elevated. Locomotion is relatively rapid, either by walking, or by swimming by ejections of water from the respiratory chamber. It is a notoriously can- nibalistic species : among abundant and choice food, the larger nymphs will eat the smaller ones, and two of equal size can not be safely kept to- gether in close quarters. Cabot ^ has figured and described the nymph, and many indifferent re- productions of his figure are current. The following brief diagnostic statement of its principal characters will serve for its recognition. Nymph, (fig. 14) Measures in total length 39 mm ; abdomen 29 mm ; hind femur 8 mm ; width of head 8 mm, of abdomen 8.4 mm. ^ Immature state of the Odonata. 1881. pt 2. 472 NEW YORK STATE MUSEUM Body slender, smooth ; colors brown and green, in a pattern of longi- tudinal streaks, well adapted to concealment among plant stems, the depth of the color varying to suit the environment. Head strongly depressed, with the eyes covering the greater part of the sides of it; labium very long, reaching posteriorly the base of the hind legs ; the mentum regularly widened from base to apex, produced median lobe with a closed median cleft ; lateral lobe suddenly rounded off at end to the incurved internal end hook, but hardly truncate; legs long and slender as befits its climbing habits, tibiae and femora faintly ringed with brown ; abdomen with strong and evident lateral spines on segments 7-9 only ; superior abdominal appendage with a well rounded apical notch, its length about seven eighths that of the inferiors, which are longer than segments 9 and 10 together; lateral appendages two fifths as long as the inferiors; spines of the ninth segment about as long as the loth seg- ment. Subfamily petj^lurinab There is but one genus and species occurring in the eastern United States : both will be recognized by the characters given in the table for major groups. Tachopteryx thoreyi Selys 1857 Uropetala tlioreyi Selys, Monographie des goniphines, p. 373 ( ^ ) 1861 Petalura thoreyi Hagen, Synopsis Neur. N. Am. p. 117 1878 Tachopteryx thoreyi Selys, Acad. Belg. (2) Bui. 46:696 ( ? ) 1898 Tachopteryx thoreyi Calvert, Am. ent. soc. Trans. 20:241 (descrip- tion) 1900 Tachopteryx thoreyi Williamson, Ent. news, 11:398-99 (habits) 1900 Tachopteryx thoreyi Williamson, Dragon flies Ind. p. 281 (descrip- tion) This species, originally described from a single male specimen taken in the vicinity of New York, has apparently not been found in the state since that time. It is now known to be distributed from Massachusetts to Florida and Texas. According to Mr Wilhamson, who has published the little that is known concerning its habits, it flies in Pennsylvania during the whole of June and the first half of July. It is ''usually observed resting in sunny situations on fences or trees, at the edges of woodland . . . stream and small marshy area near . . . Easily approached . . . once aroused, its flight is swift and strong." On June 4, 1900 D. A. Atkinson took in transformation a single female nymph of this species near Pittsburg Pa. E. B. Williamson described and figured this nymph in Entomological news. 1901. 12 : 1-3, pi i, and then very kindly loaned me the specimen for study. From this specimen I have drawn the labium and antenna shown in figure 15 and the brief statement of characters given herewith. ' Nymph. Length 38 mm. Antennae 7-jointed, depressed, hairy on lateral margins, the segments short and broad. AQUATIC INSECTS IN THE ADIRONDACKS 473 Labium short and stout, median lobe with a narrow median cleft and denticulate margin ; lateral lobes truncate on end, scarcely denticulate : no raptorial setae. Legs stout, with prominent, twisted, hair-fringed, longitudinal carinae; tarsi 3-3-3 jointed. Wing cases laid parallel along the back, their apices reaching the mid- dle of the fifth segment. Abdomen tapering beyond the fifth segment with thin flaring lateral margins showing on each of segments 4-9 an angle at the middle and a flat tooth at the apex, and with a dorsal row of hairy tubercles on seg- ments 5-9, parallel to the lateral margin but nearer the median line : ap- pendages obtuse, the superior with a broad, shallow, apical emargination. The eggs are deposited in wet, boggy places, when there is hardly any water standing, and the nymph lives in the mud in such places. Subfamily cORDULEGJVSTERirsrAE A small group of large species, inhabiting mainly clear streams that flow through upland marshes, spring bogs, etc. The imagos are strong of flight, and are oftenest seen cours- ing back and forth over some small stream, flying on a regular beat, and passing and repassing the same point at intervals of a few minutes. The collector may take advantage of this habit, and so station himself that he may reach the specimen as it passes, and capture it, if dextrous with a net. The nymphs live on the bottom in shallow water, buried in clean sand or in vegetable silt. Though buried they do not burrow, but descend by raking the sand from beneath them by sweeping, lateral movements of the legs. When deep enough, they kick the sand up over the back till only the elevated tips of the eyes and the respiratory aperture at the tip of the abdomen are exposed. By placing a live nymph in a dish of sand and water and watching, its method may be observed in a very few minutes. The whole comical performance reminds one strongly of the descent of an old hen in a dustbath. Once adjusted in the sand, a nymph (unless food tempts) remains motionless a very long time. In a dish of sand on my table, I have had a nymph remain without change of position for weeks, no food being offered it. Let any little insect walk or swim near the nymph's head, Fig. 15 Tachoptery X thoreyl Selys ; a la blum and b antenna of a female nymph. ( Mr Williamson's type ) 474 NEW YORK STATE MUSEUM and a hidden labium springs from the sand with a mighty sweep and clutches it. I fed to a nymph of Cordulegaster diastatops 14 full grown nymphs of C apni a in rapid succession, which should represent a bulk about equal to that of the nymph that ate them. It ate a dozen quickly, the last two more slowly : it had been without food sev- eral weeks. Nymphs of the species described below as C. maculatus supposition, at Saranac Inn, captured and ate young brook trout as long as themselves, when placed in their cage. So eager were they, they would rise partly from the sand on approach of a trout. Like the nymphs of the Aeschninae, they seem to have a decided preference for big game, if one may judge by the strenuous efforts they put forth when something at the limit of their capacity for capturing approaches. Our species belong to a single genus. CORDULEGASTER Lcach Of the seven species occurring north of Mexico six are found in the eastern United States, and of these six, five are likely to be found in New York state when careful collecting is done for them. But two of these, C. erroneus (from Keene valley) and C. diastatops, are on rec- ord from the state ; a third, C. maculatus is recorded below from Saranac Inn. Imagos of the six species of the eastern United States may be sepa- rated by the following table : a Eyes not contiguous ; the proximal inferior tooth of the superior abdominal appendage of the male almost completely incased within the 10th segment (subgenus Zoraena) T) Abdomen with yellow lateral spots; stigma browu diastatops hi) Abdomen with yellow half rings ; stigma yellow sayi aa Eyes contiguous ; proximal inferior tooth of superior appendage of male more or less completely exposed h Two cubito-anal cross veins before the triangles ; triangle open, or divided by a single cross vein ; stigma moderate (subgenus Cordulegaster) c Abdomen with yellow lateral spots maculatus cc Abdomen with yellow half rings erroneus 6& Usually three cubito-anal cross veins before the triangle ; triangle often divided by more than one cross vein ; stigma very long (subgenus Taeniogaster) d Abdomen witb lateral yellow spots (southern) fasciatus dd Abdomen with a middorsal line of spots obliquus ARTIFICIAL KEY TO THE SAME SPECIES a Abdomen with a middorsal line of spots obliquus aa Abdomen with yellow half rings on the segments & Face yellow sayi AQUATIC INSECTS IN THE ADIRONDACKS 475 lb Face blackish erroneous aaa Abdomen with lateral spots c Abdomen 65 mm or more in length (southern) fasciatus cc Abdomen less than 60 mm in length d Spots single on sides of abdominal segments diastatops dd With large, separate, median and apical spots on sides of middle abdom- inal segments maculatus As to the nymphs, few of them are known. Cabot^ has figured and described as C. sayi (supposition) nymphs, which, later, Hagen^ has referred to C. diastatops (supposition). These nymphs were from Maine, Massachusetts, Maryland and Virginia. It is very doubtful whether C. sayi occurs so far north as Massachusetts : owing to con- fusion of species, published records of distribution of our species of Cordulegaster need sifting. I have bred C. diastatops at Ithaca and my nymphs agree with Hagen's description, and thus confirm his supposition. In the above cited paper Dr Hagen also published brief descriptive notes on two other Cordulegaster nymphs which he referred by supposition to C. dorsalis (of the Pacific slope) and C. obliquus (the latter one, a single imperfect specimen from Texas). This is all that has been published concerning the nymphs of American species of this genus. I describe below nymphs of C. diastatops (raised) and C. maculatus (supposition), and in order to avoid repetitions, I will give herewith a general statement of the characters of nymphs of the genus : they are all very much alike. Nymphs of this genus agree in the following points : the body is stout, rough, hairy, cylindric, tapering beyond the middle of the abdomen to a pointed apex, the longitudinal axis upcurved at both ends, the tips of the eyes and the abdominal appendages being the highest points. The antennae are seven-jointed, slender. The eyes cap the angular antero- lateral prominence of the head and extend a pair of sharp points inter- nally on the vertex from their hind angles. Hind angles of the head rounded, the hind margin not obviously concave posteriorly. The labium is very large, extending posteriorly between the bases of the mid- dle legs, its dilated, spoon-shaped anterior end covering the face up to the antennae, and meeting above a convex frontal prominence, whose margin is fringed with sensory hairs. The mentum is triangularly widened beyond the middle; its median lobe is produced in a median tooth which is bifid on the median line; its lateral lobes are broad, tri- angular, concave, and bear a row of short raptorial setae just within the externa] margin, a stouter, but not longer movable hook at the end of this row, and a series of coarse, irregular interlocking teeth on the distal margin. 1 Immature state of the Odonata. 1872. pt 1, p. 13, pi. 3, fig. 2. 2 Monograph of the earlier stages of the Odonata, Am. ent. soo. Trans. 1S85. p. 290. 476 NEW YORK STATE MUSEUM Prothorax with a transverse dorsal flattened area, which is fringed with stiff hairs ; legs slender and not very long, adapted, not for running as stated by Hagen {loc. cit. p. 288), but for raking the sand aside; femora and tibiae with dorsal and ventral rows of long hairs, the ventral row on the tibiae graduating into spines at the tip, these becoming arranged in a double row on the ventral side of the tarsal segments; tarsi three-jointed; wings a little divergent on the two sides, when grown, reaching the fourth abdominal segment. Abdomen, subcylindric, arcuately upcurved toward the tip; no dorsal hooks ; lateral appendages less than one fourth as long as superior and inferiors; the transverse apical rings on the abdominal segments are somewhat remote from the apices of the segments and bear rows of very stiff" hairs, which are incurved at the tip and serve to hold a layer of sand, dirt, etc. about the body. The two species of nymphs described below may be easily separated as follows. a Lateral margins of abdominal segments 8 and 9 sharp, ending posteriorly in stout triangular, conspicuous lateral spines diastatops (raised) aa Lateral margins of abdominal segments 8 and 9 hardly acute, at their pos- terior ends a pair of minute, slender, cylindric, pointed spines, that are shorter than the hairs among which they are hidden maculatus (supposition) Of the eggs of Cordulegaster I know nothing. Field observa- tions are much needed on the matter of oviposition to observe whether they are dropped into the water, attached to supports, or inserted into plant tissues, and, if the latter, how the long, imperfect ovipositor of the female is used. Cordulegaster maculatus Selys 1854 Cordulegaster maculatus Selys, Acad. Belg. (2) Bui. 21 : 105 1861 Cordulegaster maculatus Hagen, Synopsis Neur. N. Am. p. 115 1875 Cordulegaster maculatus Hagen, Bost. soc. nat. hist. Proc. 18 : 50 (bibliography and distribution) 1893 Cordulegaster maculatus Calvert, Am. ent. soc. Trans. 20 : 246 (description) This species was not uncommon at Saranac Inn. It was to be seen during the greater part of the summer on sunshiny days coursing up and down Little Clear creek on the hatchery grounds: it was observed nowhere else. It has not been reported from New York state hitherto. The nymphs referred to this species by supposition (none of them being reared) were common in the sandy bed of Little Clear creek, in the places over which the images were observed flying; but one species was seen ; that is the reason for referring the nymphs to this species. A number of exuviae were found on the edges of the fish ponds within a few days after our arrival, but none appeared later, and, though nymphs apparently fully grown were repeatedly taken and a good many of them kept in our cages through the remainder of the season, none of them trans - AQUATIC INSECTS IN THE ADIRONDACKS 477 Fig. 16 Labium of nymph of Cordulegaster formed. I believe that the season for their transformation was past and that the period of adult life for this insect is a long one. The few speci- mens captured were all males. Nymph. Measures in total length 41 mm ; abdomen 30 mm ; hind femur 6 mm ; width of head 7 mm, of abdomen 8 mm. Body very densely rough hairy; colors (entirely obscured except after molting) yellowish marked with brown spots ; a pair of these at the base of the fore wings, a double submedian row along the dorsum of the abdo- men, oval, with apices con- vergent in each pair; external to these, another row each side with apices divergent; external to these, a less conspicuous row each side, of spots lying nearer the bases of the segments; supe- rior and inferior appendages yellow, black tipped, fringed densely on their internal mar- gins with soft black hairs ; laterals maculatus Say, supposition one fifth as long, not fringed. Mentum of labium bell-shaped in outline (fig. 16) ; median lobe very long and dilated on the cleft apex in a pair of flat ovoid lobes, with ser- rulated margins and each with an external apical denticle ; lateral lobe with 10 or II very unequal sharp teeth on distal margin, the longest of the teeth, the movable hook and the setae of about equal length, the hook several times as thick as the setae; setae five; setae on mentum 10 or 11, six or seven longer ones in a longitudinal row at the sides, and four small ones extending from the proximal end of this row toward the median line. Abdomen with segments about equal in length as far as the loth, which is about one third shorter; appendages equal the ninth segment in length ; in the female the long triangular lobes of the ovipositor extend to the apex of the ninth segment, against which they are closely applied ; lateral spines, minute cylindric pointed rudiments, hidden among the hairs of the lateral margins, on the eighth and ninth segments. Cordulegaster diastatops Selys 1854 Thecapliora diastatops Selys, Acad. Belg. (2) Bui. 21; 101 1886 Cordulegaster lateralis Scudder, Bost. soc. nat. hist. Proc, 10: 211 1872 Cordulegaster sayi (nymph) Cabot, Mus. compar. zool. Mem. v. 2, art. 5, p. 13, pi. 3, fig. 2 1885 Cordulegaster diastatops (nymph, supposition) Hagen, Am. ent* soc. Trans. 12:290 (description) 1878 Thecaphora diastatops Selys, Acad. Belg. Bui. p. 685 (descrip- tive notes and corrections) 1895 Cordulegaster diastatops Calvert, N. Y. ent. soc. Jour. 3:45 (listed from New York state) 478 NEW YORK STATE MUSEUM This is a common species about the upland spring bogs near Ithaca and McLean N. Y. I have collected the nymphs by hundreds from the brownish vegetable debris of the puny streams trickhng through such places. The nymph differs from the preceding species in being a trifle smaller, and considerably less hairy; the lateral margins of segments 8 and 9 of abdomen are thin and sharp and bear sharp triangular spines; the labium is less widened just before the bases of the lateral lobes ; the median lobe is less produced, more deeply notched in the middle, and the two lobes separated by this median notch are again cleft by a lesser notch. Possibly these differences in median lobe of labium and in lateral margins of abdominal segments 8 and 9 may prove constant for the sub- genera Z o r a e n a and Cordulegaster. Skirmners This family is a host, and includes many of the commonest of our species. Most of them are of well sustained flight, and are seen con- ^, . tinually hovering over the sur- face of still water, or are met with on the uplands while for- aging. The females do not insert their eggs into the tis- sues of plants, but drop them loosely into the water, or hang them in strings about plant stems at the surface of the water. The nymphs are sprawlers on the bottom, mainly in shal- low water, or clamberers over fallen plant stems, and are protectively colored. They agree in the following char- acters: the labium (fig. 17) is maskhke, spoon-shaped, with raptorial setae, and with its lateral lobe toothed on its distal margin; the antennae are seven-jointed, and setiform; the tarsi are three-jointed, with the third joint never as long as the two basal ones together; the wing cases are Fig. 17 Diagram of the Libellulid nymph labium (P e ri- themis dom.itia). Sm submentum ; m, mentum ; ms mental setae ; ml median lobe ; II lateral lobes ; Is late- ral setae; t teeth; h movable hook AQUATIC INSECTS IN THE ADIRONDACKS 479 long, reaching the sixth abdominal segment when the nymph is grown ; lateral spines are present on abdominal segments 8 and 9, but the dorsal hooks are very variable, and often wanting. Of the three subfamilies characterized below, the first one is here newly set apart; the other two are so closely allied that no single abso- Fig. 18 Bases of wings of Leucorhinia glacialis Hagen. Ccosta; Scsubcosta; K radius; JIf media; Cw cubitus; A anal vein; ar areulus; t triangle; f ' subtriangle ; s supra triangle ; a. anal loop lately distinctive character has yet been found that will separate all the imagos. A combination of characters seems to be necessary for dis- tinguishing both imagos and nymphs: a combination is therefore used in the following tables. KEY TO SUBFAMILIES Imagos a The triangle of the hind wing placed considerably beyond the areulus ; the anal loop well developed, and hardly longer than broad; with more than two cubito-anal cross veins . , Macromiinae aa The triangle of the hind wing (fig. 18) retracted to the level of the areulus, or even passing it a little sometimes; the anal loop, greatly elongated (except in Nannothemis) and becoming foot-shaped: one or two cubito-anal cross veins. 480 NEW YORK, STATE MUSEUM h Sectors of the arculus (veins M1-3 and M4 ) distinctly separate at tlieir departure from the arculus; anal loop elongate, but not distinctly foot- shaped, the toe part being little or not at all developed ; the last antenodal cross vein extending from the costal to the radial veins (except in D. lintneri, in which it generally extends only from the costal to the subcostal) ; colors often metallic blue or green on thorax and abdomen Cordulinae p. 484 hh The sectors of the arculus in close apposition or completely fused for a little way beyond the arculus; anal loop generally distinctly foot-shaped, with well developed "toe"; the last antenodal cross vein often discontinuous at the subcostal vein Libellulinae p. 506 Nymphs a Head with a prominent pyramidal frontal horn ; abdomen flat, and almost circular in outline as seen from above ; legs long, giving a spiderlike aspect to these big nymphs; 10th abdominal segment well exposed, not telescoped in the apex of the ninth segment; teeth on the lateral lobes of the labium with deep incisions between them Macromiinae aa Head without pyramidal frontal horn ; abdomen less flattened, more elongate ; teeth on the lateral lobes of the labium much wider than high. & Lateral appendages of the abdomen more than half as long as the inferiors ; hind femora longer than the head is wide; when the lateral spines are long (fig. 19s), then there is a fall series of big, cultriform dorsal hooks on the abdomen Cordulinae && Lateral abdominal appendages generally less than half the length of the inferiors ; hind femora generally as long as the head is wide ; often when the lateral spines of the abdomen are long the dorsal hooks are wanting or reduced Libellulinae Subfamily ivia^croiviiinae. A small group of large species, more distinct than any other group within the family. The imagos are bulky and not very graceful, hairy and not strikingly beautiful in their coloration, but their flight is strong and well sustained : they gHde through the air with the fearless abandon of masters of a situation. The nymphs are quite unique in the family in the possession of a flat abdomen, almost circular in outline, recalling that ofHagenius, though less flat and circular than that, and an erect pyramidal horn on the front of the head ; in this last character, they are unique among all Odonata. They He flat on the bottom where there is Httle mud, or oftener, on some nearly bare ledge in the border of a stream, with their thin legs radiately arranged, and the body almost completely covered with silt. Thus they await their prey and seize it when it approaches. They are all an undetermined number of years reaching maturity. Our two genera may be separated as follows : AQUATIC INSECTS IN THE ADIRONDACKS 481 Imagos a Dorsal surface of the bead Tvifcli the occiput larger than the vertex; suh- triangle of the fore wings usually divided by a cross vein ; four to six cross veins in the space above the bridge (see fig, 9) Didymops aa Dorsal surface of the head ■with the occiput much smaller than the vertex ; subtriangle of the fore wings generally open; two or three cross veins in the space above the bridge Macromia Nymphs a Head hardly as wide across the eyes as across the bulging hind angles ; lateral spines not incurved, those of the ninth abdominal segment hardly surpassed by the tips of the appendages ; dorsum of the 10th abdominal seg- ment with no trace of a dorsal hook Didymops aa^Head widest across the eyes ; spines of the ninth abdominal segment shorter, not nearly reaching the level of the apices of the appendages ; dorsum of the 10th segment with a very rudimentary dorsal hook Macr omi a DIDYMOPS There is a single species, Didymops transversa Say 1839 Libellula transversa Say, Acad. nat. sei. Phil. Jour. 8:19 1861 Didymops transversa Hagen, Synopsis Neur. N. Am. p. 135 1875 Macromia transversa Hagen, Bost. soc. nat. hist. Proc. 18 : 57 (full bibliography, and distribution) 1890Macromia transversa Cabot, Immature state Odon. pt 3, p. 14-16, pi. 1, fig. 3 (full bibliography, description of nymph and distribution) 1893 Didymops transversa Calvert, Am. ent. soc. Trans. 20:250 (de- scription) 1899 Didymops transversa Kellicott, Odon. Ohio, p. 88 (description) 1900 Didymops transversa "Williamson, Dragon flies Ind. p. 307 (de- scription) This is a common species in woodland streams and ponds, in water of a little depth, in shaded pools, etc., where there is little vegetation. It was not very common at Saranac Inn, but nymphs were taken in the borders of Little Clear pond and creek, and exuviae were found along the eastern shore of Lake Clear, hung up in the bushes, or attached to large rocks several yards from the water's edge. Imagos were observed only about the borders of the larger bodies of water. They could always be seen darting in and out of the edges of the woods on the fragrant shores of Little Green pond. Nymph. (PL i8, fig. 8) Measures in total length, $ 2j mm, ? 29 mm; abdomen 19mm: hind femur 11 mm; width of head 7 mm, of abdomen 13 mm. Body flat, thin edged, with legs wide apart at bases and sprawhng. Color yellowish below, mottled brownish above, the 482 NEW YORK STATE MUSEUM mottlings darker toward the middle line, and on the lateral ridges of the thorax; a darker band covering the top of the head, including the eyes, but not the frontal horn, which is yellowish, sprinkled on its upper side with brownish prickly granulations. Head compact, bulging behind the eyes, which cap the elevated anterolateral angles; antenna with the basal segment twice as long as the second, about as long as the third; the succeeding segments gradu- ally becoming a little shorter; hind angles of the head obtuse angled superiorly; rear of head a little concave; prothorax with a flat, angular fringed process each side, fitted snugly against the sides of the head; tarsi with the second and third joints of about equal length, the first joint about one third as long; femora and tibiae ringed obscurely with brown; wing cases reaching almost to the apex of the sixth abdominal segment. Abdomen flat, with thin, flat lateral margins, and a median row of large, cultriform, dorsal hooks on segments 3-9, these same segments longer at the sides than on the median line; long, straight, lateral spines on segments 8 and 9, on 8 slightly divergent, on 9 parallel, as long as or longer than the body of the segment ; loth segment annular, inserted into an apical excavation of the ninth, one third as long as the length of the ninth on its middorsal hne; appendages about as long as 9 above, subequal, or the laterals a very little shorter. Thorax broadly excavate below for the reception of the labium, with a pair of supporting humps beside it on the mesothorax and another one behind it on the metathorax. Labium large; mentum broadly triangular, strongly contracted at its basal fourth, with a moderately prominent and declined median lobe, and about seven raptorial setae each side, the two inner ones quite small ; lateral lobe ample, concave, with five raptorial setae and a hook that is stouter but httle longer than the setae; distal margin with about six or seven crenate oval teeth, each bearing several graduated spinules. MACROMIA Two species are regional, but only one of them has as yet been taken within the state (M. illinoien sis); the other (M. t aen iola t a) is found from Pennsylvania southward as far as Florida. Neither has as yet been bred. Cabot ^ has described nymphs referred by supposition to each. Till these are reared it is hardly worth while to repeat descrip- tions in detail. It will suffice to give a general account of the characters of nymphs of this genus, and to state in tabular form the chief differences between the two species of nymphs believed to be the two species named. The nymphs of the genus are short and flat, with widely sprawHng legs. The shape of the prominent eyes, elevated on the laterosuperior angles of the head, and of the frontal horn, offer specific characters : the head is widest across the eyes, and slowly narrowed behind them, to the obtuse hind angles, each of which bears a tubercle on its upper aspect. The wings reach well over the sixth abdominal segment. There are strong cultriform, dorsal hooks on abdominal segments 2-9, and there is 1 Immature state of the Odonata. 1890. pt 3. AQUATIC INSECTS IN THE ADIRONDACKS 483 a low median ridge representing another on the loth segment, often httle evixient. The lateral spines, which occupy the sides of the eighth and ninth segments, are generally stout and flattened, and do not reach the level of the tips of the appendages. The loth abdominal segment is a little shorter than the ninth. Imagos a Length of abdomen generally less tban 50 mm ; expanse of wiug less tban 100 mm; thoracic dorsum usually without yellow stripes illinoiensis aa Length of abdomen about 60 mm ; expanse of wing more than 110 mm; dor- sum of the thorax with a pair of short, yellow stripes taeniolata Nymphs a Lateral spines of abdomen directed posteriorly, hardly incurved; pyramidal horn on the front of the head acute at apex. ..illinoiensis, supposition aa Lateral abdominal spines strongly incurved at the tip; pyramidal horn on the front of the head obtuse, hairy taeniolata, supposition Macromia illinoiensis Walsh 1862 Macromia illinoiensis Walsh, Acad. nat. sci, Phil. Proc. p. 397 1893 Macromia illinoiensis Calvert, Am. eut. soc. Trans. 20: 251 (de- scription) 1897 Macromia illinoiensis Van Duzee, N. Y. ent. soc. Jour. 5:89 (listed from Grand Island) 1899 Macromia illinoiensis Kellicott, Odon. Ohio, p. 87 (description) 1900 Macromia illinoiensis Williamson, Dragon ilies Ind. p. 308 (descriptiou) 1890 Macromia illinoiensis (nymph supposition) Cabot, Immature state Odon. 3 : 16, pi. 1, fig. 2 and pi. 2, fig. 1 A species which ranges from New Hampshire to Texas. Though taken but once as yet within the state, it probably dwells in the borders of a number of our larger bodies of water. I have not seen the imago at large. I have seen a few of the nymphs referred to this species, and may add a descriptive note covering some points unnoticed by Cabot. A nymph 26 mm long has a length of abdomen of 16 mm ; of hind femur of 11 mm; a width of head of 7.5 mm, of abdomen of 11 mm. Head a little narrowed behind the very prominent eyes to the hind angles, above each of which is a little superior tubercle ; labium greatly widened anteriorly, and concave, forming an immense mask; lateral setae six, with two little axial setae at the base of the lateral lobe within; mental setae five each side, close together in row, with several more minute, detached ones nearer the median line; teeth about five, large, oblique, each armed with about four or five spinules. 484 NEW YORK STATE MUSEUM The few nymphs I have found were all obtained from clayey banks among wave-washed roots of trees, in places most difficult to use a net. Macromia taeniolata Rambur 1842 Macromia taeuiolata Rambur, Ins. Near. p. 139 1861 Macromia taeniolata Hagen, Synopsis Neur. N. Am. p. 132 1874 Macromia taeniolata Hagen, Bost. soc. nat. hist. Proc. 16 : 359 1893 M acrom i a tae n io la ta Calvert, Am. ent. soc. Trans. 20:250 (de- scription) 1899 Macromia taeniolata Kellicott, Odou. Ohio, p. 86 (description) 1900 Macromia taeniolata Williamson, Dragon flies Ind. p. 309 (de- scription) 1890 Macromia taeniolata (nymph, supposition) Cabot, Immature state Odon. Pt 3, p. 9, pi. 2, fig. 4. Distributed from Pennsylvania to Florida and Illinois. KEY TO NORTH AMERICAN GENERA OF CORDULINAE (s. sir.) Images a Veins M4 and Cui in the fore wing parallel or a little divergent apically, the number of rows of cells between them increasing toward the margin of the wingi Neurocordulia aa Veins M4 and Cui in the fore wing approximated toward the margin of the wing b The second cubito-anal cross vein (and therefore, the subtriangle) normally present in the hind wing (absent occasionally in Helocordulia) c Triangle of hind wing divided by a cross vein Epicordulia cc Triangle of hind wiug without cross vein, open d Anal loop symmetrically truncated at its distal end, with but three cells at the end ; stigma very narrow and sharp-pointed at its ends Helocordulia dd Anal loop unsymmetrieally truncated at its distal end, with more than three cells at the end ; stigma wider and less sharply pointed Somatochlora ib The second cubito-anal cross vein absent in the hind wing c Triangle of the fore wing traversed by a cross vein, with two complete rows of cells in the space beyond it d Wings with black basal markings; inferior appendage of the male, not bifurcated Tetragoneuria 1 One species, the little Cordulla Untneri of Hagen, may seem to belong in this section of the table, though of course, not in the genus Neurocordulia; it is also a synthetic type, lack- ing the special corduline features of venation, which I take to be 1) the approximation of veins M^ and CUj,and 2) the general reduction of cross veins ; it shows strong libellullne affinities in tbe conformation of the anal loop and in the possession of a half-antenodal cross vein just before the nodus. We may expect that its nymph when discovered will throw light on its true relation- ships. I leave it here in the genus D or o cor dull a beside the two species with which it has hitherto been associated. AQUATIC INSECTS IN THE ADIRONDACKS 485 dd Wings clear; inferior abdominal appendage of the male deeply bifur- cated, the forks again notched at tips; never with less than five antenodals in the hind wing, or with the triangle of that wing traversed by a cross vein Cordulia cc Triangles of the fore wings open D o r o c or dul i a So well marked are these genera that they may generally be recognized at a glance by the following. Single distinctive characters Epicordulia alone has large brown spots at base, nodus and stigma of all wings. Tetragoneuria alone has but four antenodals in the hind wing. Helocordulia alone has the stigma very narrowly diamond-shaped, with the ends of it meeting the sides by an angle of 3o°-35°. Cordulia alone has the inferior abdominal appendage of the male deeply bifurcated. Dorocordulia alone has the triangle of the fore wing free from cross veins. Neur'ocordulia has been sufficiently distinguished above ; S o m a t - o c hi or a possesses none of the characters of this list. Ny77iphs a Lateral setae four or five ; mentum about as long as wide.. Epicordulia aa Lateral setae seven ; mentum of labium longer than wide h Abdomen with large, laterally flattened, generally cultriform dorsal hooks c Lateral spines of the ninth segment longer than half the length of that segment ; dorsal hooks on segments 3-9, highest on 6, cultriform, and sharp Tetragoneuria cc Lateral spines of the ninth segment shorter than half of that segment ; dorsal hooks less developed d Dorsal hooks on segments 4-9 laterally flattened, but obtuse at apices, and not cultriform Somatochlorai dd Dorsal hooks on segments 6-9, longest on 8 and cultriform Helocordulia M Abdomen witb no dorsal hooks, or with these rudimentary, not flattened laterally or cultriform, but small obtuse or pointed prominences c Hind angles of the head rounded ; lateral spines of the ninth abdominal segment one fifth as long as that segment Cordulia cc Hind angles of the head angulate superiorly ; spines of the ninth abdom- inal segment one third as long as that segment Dorocordulia 1 There can be little doubt that the unknown nymphs of the numerous species of this genus will necessitate an amplification of the characters herein stated. S. elongata appears to be the only American species yet reared. Cabot described a nymph as that of Som. alb lei net a, supposition, but I am unable to say whether the supposition was correct : so far as one may judge from his figure, that one might as well have been Cordulia shurtleffl. The typical Somatochlora metallica of Europe has dorsal hooks on segments 3-9 of abdomen, with the posterior ones bet- ter developed than in S. elongata. It must be borne in mind by those who use this table that it is based only on the nymphs of the species herein described. 486 NEW YORK STATE MUSEUM NEUROCORDULIA No species of this genus has been taken within the limits of this state, but the following one is regional, being distributed from Massachusetts to Indiana. The nymph of the genus is unknown, unless the one described below be it. That nymph described and figured by Cabot and indicated as belonging possibly to this species, is Libellula pulcheUa. Neurocordulia obsoleta Say 1839 Libellula obsoleta Say, Acad. nat. sci. Phil. Jour. 8 : 28 1839 Libellula polysticta Burmeister, Handb. ent. 2 : 856 1861 Di dy mop s obsoleta Hagen, Synopsis Neur. N. Am. p. 136 1873 Epitbeca obsoleta Hagen, Bost. soc. nat. hist. Proc. 15 : 269 1863 Cordulia modesta Walsb, Eut. soc. Phil. Proc. 2 : 254 1890 Epitbeca obsoleta Hagen, Psycbe, 5:369, pi. 1, %. 7-9 (critical notes, with figures of the accessory genitalia) 1893 Neur o c or dull a obsoleta Calvert, Am. ent. soc. Trans. 20:252 (description) 1900 Neurocordulia obsoleta Williamson, Dragon flies Ind. p. 312 This species seems to be everywhere rare. I have not seen it at large. There are very few specimens in collections. It is very different in many particulars from all the other Cordulinae. It is very desirable that some one should rear it. The imago will be easily recognized by the characters given in the table. I describe below a nymph from Penn- sylvania which probably belongs here. Nymph. (Not grown) Measures in total length i8 mm; abdomen 8mm ; hind femur 5 mm ; width of head 5 mm, of abdomen 8 mm ; length of body without antennae 17 mm. A singularly flat-bodied, short-legged nymph with exceptionally con- tracted abdomen, smooth, blackish m color, with traces of paler bands on the femora and tibiae. Head dorsally flattened, with a pair of low, submedian, vertical tubercles, and a shelf-like, scurfy pubescent frontal ridge, as long as the two basal segments of the antennae; antennae seven jointed; joint i cylindric, 2, globular, these of equal length ; segments 3-7 slightly decreas- ing in length to the conic seventh segment. Hind angles of the head obtuse, but prominent posteriorly, overhanging the front of the protho- rax; hind margin of the head excavate between the hind angles. Labium short and broad, hardly extending posteriorly beyond the bases of the fore legs; mentum broadly triangular, contracted at its base, concave within, its sharp superolateral margins spinous at both ends; median lobe moderately prominent, with a few minute spinules on the front border of it, declined ; mental setae eight or nine, the three or four innermost ones quite small each side; lateral lobes triangular, concave within, its distal border cut in about seven semi-elhptic teeth, each armed at its tip with two or three spinules , lateral setae five ; movable hook a little longer and stronger than the setae, gently arcuate. There is a distinct occipital ridge on the rear of the head below the level of the vertex, closely apphed to a corresponding ridge on the front AQUATIC INSECTS IN THE ADIRONDACKS 487 margin of the prothorax. The dorsal shield of the prothorax farther bounded on the posterior side by a transverse ridge, which curves forward at its ends to terminate in a pair of prominent lateral processes ; there is also an obtuse supra-coxal process each side which extends forward close beside the head halfway from the hind angles of the head to the eyes. Body depressed; legs smooth, wide apart, the three pairs successively more remote from each other at base, the middle and hind femora each with a superior ridge, the fore and middle tibiae each with a ridge, start- ing at its base exteriorly (dorsally) and at once curving to extend down its anterior face; tarsi three-jointed, the third joint about as long as the two basal together, the claw short and stout, about as long as the basal joint. Abdomen flat, suborbicular, granulate, with a row of oval smooth scars midway between the median line and the lateral margin each side on segments 4-8; wing cases reaching but to the middle of the fourth abdommal segment (the nymph is apparently not grown); there is a row of conspicuous dorsal hooks starting from between the wing cases and end- ing on segment 9 ; strongly flattened laterally, not hooked at all, but erect, and rounded on tips, highest on the sixth segment; ventral sutures wide apart, slightly convergent posteriorly, disappearing on the ninth segment; basal abdominal segments extremely contracted, segment 1 telescoped by the metathorax, visible only in the middle of the ventral side; genitalia ( S ) visible at the midventral apex of segment 2; lateral spines on 8 and 9, long and sharp, divergent on 8, parallel on 9 and as long as the segment, greatly surpassing the appendages; segment 9 excavate above between the lateral spines, to inclose the annular loth segment and the appendages, one half as long on the middorsal as on the midventral line ; inferior appendages about as long as segment 9 is on the dorsal side, the superior and the laterals successively shorter, the latter a little longer than half the inferiors; segment 10 about half the dorsal length of the ninth segment ; inferior apical and lateral margins of the ninth segment fringed with long hairs. A single nymph^, sent me by Dr Calvert, from the collection of the Academy of natural sciences of Philadelphia, bearing the label, "H. C. Borden, Pa. Oct. 26, '95 ". The flat abdomen with erect blunt dorsal hooks and smooth lateral scars, and the elongate third tarsal segment recall Ha genius, while the broad mask- shaped labium, the vertical tubercles and the frontal ridge recall Epicordulia. The transverse occipital ridge, the curving carina on the fore and middle tibiae, and the extreme abbreviation of the basal abdominal segments are characters which I do not recall having observed in any other nymphs whatever. 1 Since the above was written I have received exuviae from Dr Calvert, taken at White lake in the Catskllls, and from E. B. Williamson, taken at Nashville Teun., of this same species. The length of the nymyh when grown is 21 mm. I now feel quite certain that these belong to Neu- rocordulia. 488 NEW YORK STATE MUSEUM EPICORDULIA We have a single species. Epicordulia princeps Hagen Water prince (PI. 22, fig. i) 1861 Epitbeca princeps Hagen, Synopsis Neur. N. Am. p. 134 1875 Cordulia princeps Hagen, Bost. soc. nat. liist. Proc. 18 : 61 (bibliograpLy) 1893 Epicordulia princeps Calvert, Am. ent. soc. Trans. 20 : 251 (de- scription) 1899 Epicordulia princeps Kellicott, Odon. Ohio, p. 88 (description) 1900 Epicordulia princeps Williamson, DragOQ flies Ind. p. 310 (de- scription) 1890 Epitheca princeps Cabot, Immature state Odon. pt 3, p. 25, no. 12, pi. 3, fig. 3 and no. 13, pi. 4, fig. 3 (juv. nympb) 1889 ''Libellulina nymphs nos. 10 and 12." Garman, 111. state lab. nat. hist. Bui. 3, 3 : 179 This species is distinguishable from all the following even in flight by its large size and its brown wing blotches at nodus and stigma. It is a widely distributed species, locally common where there are ponds or sluggish streams with muddy, reed-grown banks. Images appear on the wing in May and continue flying through midsummer. They seem ab- solutely tireless in flight; very rarely indeed is one seen resting. The males at least prefer the surface of still water, over which they will sweep back and forth in zigzag lines and broad curves hour after hour. The nymphs sprawl on the bottom amid fallen reeds, or clamber over submerged logs. In winter I have found numbers of them crowded in the crevices of a submerged stump. Transformation takes place very early in the morning. The nymphs will crawl several meters from the edge of the water if necessary in order to find a proper support. They are stift' creatures with legs set wide apart, and, not being good climbers of reeds, generally seek some broader supporting surface, such as the side of a stump, or a cluster of grass blades. The eggs are dropped by the female while flying alone, dips being made far out in open water, and widely distributed. Nymph. (PL 21, fig. 2) Measures in total length 27 mm ; abdomen 17 mm; hind femur 8 mm; width of head 7.5 mm, of abdomen 8 to 12 mm, there being very great variation in this last measurement. Since this nymph has been figured and described by Cabot, it will suffice here to give a brief statement of the more distinguishing charac- teristics. Head a little narrowed behind the small eyes, which cover the anterolateral angles; there is a pair of low conic tubercles on the top of the head, these larger in younger nymphs, and sometimes even cultri-- form. The statement that the young nymphs of this species do not differ AQUATIC INSECTS IN THE ADIRONDACKS 489 from the grown nymph in this respect is sometimes (but very rarely) true. Labium with four (less often five) lateral setae, and four larger mental setae each side, with one or two lesser ones near the median line. Thorax with broad sterna. Abdomen depressed, triquetral ; dorsal hooks large, cultriform, in a very regular series, on segments 2-9 ; lateral spines on segments 8 and g, those of the ninth segment surpassing the level of the tips of the append- ages; superior appendage very nearly as long as the inferiors, laterals a little more than half as long as the inferiors. There are two indistinct and interrupted bands of brownish markings, extending from the hind angles of the head to the bases of the spines on the ninth abdominal segment, and there are darker rings on tibiae and femora, discoverable specially after molting. This species was seen but a few times at Saranac Inn, and no speci- mens were taken either as nymphs or imagos. It is not uncommon in other places in the state, and will probably be found quite generally dis- tributed when proper search is made for it. TETRAGONEURIA This North American genus is one of the most important, most generally distributed, and most common in the subfamily. The imagos are somewhat scarce in collections, but they are by no means so in nature. Because of their superb aerial powers they are not often taken in flight. They depart widely from the regular haunts of the less active species Avhile foraging, and thus often escape the specialist who is collect- ing for dragon flies in particular. The roving habits of the imagos account sufficiently for the wide distribution of most of our species. About an lUinois pond in which Epicordulia princeps and Tetragoneuria cynosura were the only Corduhnae present, I have watched day after day the little Tetragoneuria chasing the big Epicordulia about in air, much as a kingbird chases and harasses a crow, surpassing by its swiftness and by its ability to make quick turns in air. Nymphs of this genus may be found in almost any pond; they are often found in enormous numbers. By far the easiest way to get imagos is to capture well grown nymphs and rear them. Nymphs of this genus agree so closely that I give here a general account of thiem, which, for specific descriptions will only need to be supplemented by the specific characters stated in the following table ; the differences therein stated are the only differences I know between the species. The nymphs are trim and smooth, with depressed abdomen and long lateral spines. The general color is greenish or yellowish, with a 490 NEW YORK STATE MUSEUM longitudinal band of brown each side of the thorax, rings on femora and tibiae, and obscure, interrupted, longitudinal rows of spots on the abdomen. Head compact, with eyes very prominent laterally, and the front somewhat swollen between the bases of the antennae ; labium with its mentum distinctly longer than wide, the median lobe prominent, dechned, minutely spinulose on its front border, with two stouter spinules at the sides of the apical angle; lateral setae seven ; mental setae six to nine; movable hook shghtly incurved, and sharply pointed; teeth crenate, spinulose. Abdomen roof-shaped ; segments 3-9 about equal in length, the loth a minute annular segment almost included within the apex of the ninth; dorsal hooks on segments 2-9, spine-like anteriorly where covered by the wings, distinctly cultriform posteriorly ; lateral spines on segments 8 and 9 long and broad at base. Four species are tabulated below: one of these, T. spinosa, has not been hitherto recorded from this state. These four were all common at Saranac Inn, excepting the typical T. cynosura. So common were they, in fact, that I stumbled on two desirable bits of information concerning the genus that I should probably have missed had they not been very common. The first of these relates to the proportionate abundance of the sexes. Males mainly are collected by the ordinary methods ; and for half a century or more students of the group have been remarking on the striking preponderance of males in this and other genera. 1 collected on Blueberry island in Little Clear pond in about 10 minutes in cast skins of T. spin i ger a and T. s e m i a qu e a , intermixed, taking them as they came, without any selection whatever. These were separated as to species and sexes (the males being easily recognized by the indications of the secondary genitalia on the ventral side of the second abdominal segment) and counted, with the following results : T. spinigera, ,3522, $824; T. semiaquea, ^s 25, $ s 40, in both cases a slight excess of females. I once counted a lai'ge number of skins ofT. cynosura, and E. princeps taken from Purington lake at Galesburg 111. I have not the figures resulting from the count, but I remember distinctly that there was in each case a slight excess of females. The females are more shy and seclusive, and therefore less often taken. My breedings have never revealed any material excess in numbers of either sex for any species; and these are certainly more reli- able than chance captures in air. An acquaintance with the eggs of Tetragoneuria was likewise almost forced on me. These are laid in strings, attached together in masses (as shown in fig. 19) and hung on partly submerged twigs at the surface of the water. These were very common objects about the shores of Little Clear pond. I did not see any of them laid. That they belong AQUATIC INSECTS IN THE ADIRONDACKS 491 to Tetragoneuriais, therefore, an inference : it is sufficiently justi- fied by the following considerations. i) Tetragoneuria was the only Hbellulid sufficiently common at the pond to have produced the enormous number of eggs observed there. I think one might easily have filled a barrel with the clusters that could have been picked up at the surface of this pond : the cluster shown in the figure (which was smaller than the average) contained about 110,000 eggs (counted in part, and estimated), and with its enveloping gelatin Fig. 19 Eggs of Tetragoneuria hung on submerged twigs near surface of the water would have about filled a half pint measure. These clusters are doubtless the work of a number of females; the separate strings are often indicated by the ends left hanging free. These are undoubtedly libellulid eggs : none of our larger Libellulinae lay their eggs in strings; nor do the smaller Cordulinae, but the European genus E p i t h e c a , not distantly related to Tetragoneuria, does so. No other Cordulinae were common at this pond. I did not get more than a single nymph or imago of any other save C'ordulia shurt- leffi, and of that less than a dozen in all, there. But Tetragoneurias were abundant above all that I have ever seen elsewhere. They were scattered all about the margin excepting, perhaps, the bare shores of part of the north side, and were apparently rather uniformly distributed. I counted the number of cast skins of Tetragoneuria, without regard to species, clinging to the thin grass tussocks and fallen twigs along the water's edge for a distance of several rods at two places : at the north 492 NEW YORK STATE MUSEUM side of the bay in Blueberry island, and on the outside of the cape which projects across the outlet, and found the number averaged 30 to a meter in distance along the shore line. When one reflects that there were miles of favorable shore line in this pond, the number of images suggested by a little calculation will account for a considerable quantity of eggs. 2) I hatched thousands of these eggs. While the nymphs of Libellu- lidae, when new-hatched, look much alike, these showed corduline char- acters quite as much like Tetragoneuria as any other. Fig. 20 Lateral and dorsal views of the abdomen of ttie nymph of Tetragoneuria cynosura Say. a Appendages ; h dorsal hooks ; s lateral spines Of the three species found at Saranac Inn I bred two species of the nymphs, and found other nymph skins which I have below referred by sup- position to the other species (T. spin OS a). The recognition charac- ters for imagos and nymphs of the four species of the state are given below in tabular form. AQUATIC INSECTS IN THE ADIRONDACKS 493 SPECIES OF TETRAGONEURIA hnagos a Frons with a black T snot above; triangle of hiad wings generally without a cross vein spinigera aa Frons without a T-spot above ; triangle of hind wiugs generally traversed by a cross vein Z) Superior appendage of the male not declined at tip, and without superior ante-apical spine. Hind wings generally with four antenodal cross veins. c Hind wing with isolated basal streaks which hardly surpass the level of the first antenodal cross vein cynosura cc Hind wings with broader, and more confluent markings, reaching the level of the third or fourth antenodal cross vein semiaquea Z»6 The superior appendage of the male strongly declined at the lip beyond a superior ante-apical spine ; hind wings generally with five antenodal cross veins, some of the antenodals surrounded by fuscous spots. .. s p i n o s a Nymphs a Spines of the ninth abdominal segment strongly divergent, their tips dis- tinctly wider apart than their bases on the outer sides spinigera aa Lateral spines of the ninth segment, very slightly or not at all divergent h Spines of the ninth abdominal segment longer than the segment c Spines of the ninth segment hardly longer than is the segment on its dorsal side ( fig. 20) cynosura CO Spines of the ninth segment one third to one half longer than is the segment on its ventral side semiaquea 5& Spines of the ninth segment distinctly shorter than that segment, and slightly incurved at tips spinosa, supposition Tetragoneuria spinigera Selys 1871 Tetragon euria spinigera Selys, Acad. Belg. (2) Bui. 31:269 1897 Tetragoneuria spinigera Van Duzee, N. Y. ent. soc. Jour. 5:90 (listed from Buffalo) 1897 Tetragon euria spinigera Calvert, N. Y. ent. soc. Jour. 5:95 (listed from Buffalo) 1900 Tetragone u ria spinigera Williamson, Dragon flies Ind. p. 311 (description) To the above record by Van Duzee of this species from Buffalo (repeated by Calvert in his list), I have to add two localities. It was exceedingly abundant at Saranac Inn during the month of June, flying about the grounds of the hatchery in company with the other two species occurring there — flying, also, about every other little clearing in the forest, foraging. It was very common toward the mouth of Buttermilk creek near Ithaca in June 1897. 494 NEW YORK STATE MUSEUM Tetragoneuria cynosura Say Dog-tail 1839 L ibell nla cynosura Say, Acad. uat. sci. Phil. Jour, 8:30 1839 Ep oph thalmi a lateralis Burmeister, Handb. ent. 2:847 1873 Cordulia cynosura Hagen, Bost. soc. nat. hist. Proc. 15 : 271 1861 Cordulia lateralis Hagen, SynopsisNeur.N. Am. p. 139(descriptiou) 1893 Tetragou euri a cynosura Calvert, Am. ent. soc. Trans. 20:252 (description) 1895-97 Tetragon euria cynosura Calvert, N. Y. ent. soc. .Jour. 3:46 and 5 : 93 (listed from Ithaca, Lake George, Black Eock) Tetragoneuria cynosura Kellioott, Odon.Ohio,p. 89 (description) 1900 Tetragoneuria cynosura Williamson, Dragon flies Ind. p. 311 1890 Epitheca cynosura (nymph) Cabot, Immature state Odon. pt 3, p. 28 This species, which has hitherto been recorded from but few localities within the state, is likely to be found in most large ponds in central and western New York. I have but one additional locality to record. I have received specimens from Prof. Herrick collected at Canandaigua. I have not united with this species semiaquea Burmeister, notwith- standing that I think them one species showing racial variations, because there is no difficulty, so far as I have observed, in separating the imagos on the basis of the color distinction long in use, and because my bred nymphs do not agree very closely, and I have not had time for the study of a long series of these nymphs. I would call attention, however, to a fact indicating either that they will probably be found to intergrade, or that some one has made an error or mixed his specimens. Cabot de- scribed a longer and a shorter type of nymph of the straight-spined form : the one with the longer spines was bred and was T. cynosura; the one with the shorter spines was referred to T. s e m i a q u e a on sup- position. From the shorter spined of my two with straight spines I bred abundantly in Illinois the typical T. cynosura. I have observed, however, that there is considerable variation in the length of these spines: there seems to be much less of it in their direction. While it seems likely that T, semiaquea will eventually rank as a race of T. cynosura, pending farther study, I have listed them separately here. Tetragoneuria semiaquea Burmeister 1839 Lib ell u la semiaquea Burmeister, Handb. ent. 2 : 858 1842 Cordulia complanata Eambur, Ins. Neur. p. 145 1874 Cordulia semiaquea Hagen, Bost. soc. nat. hist. Proc. 16 : 360 1861 Tetragoneuria semiaquea Hagen, Synopsis Neur. N. Am. p. 140 (description) 1893 Tetragoneuria semiaquea Calvert, Am. ent. soc. Trans. 20 : 252 1895-97 Tetragoneuria semiaquea Calvert, N. Y. ent. soc. Jour. 3 : 46 and 5 : 93 (listed from Ithaca, Baldwinsville, Black Eock) AQUATIC INSECTS IN THE ADIRONDACKS 495 Tetragoneuria spinosa Hagen 1878 Tetragoueuria spinosa Hagen, Acad. Belg. (2) Bui. 45 ; 188 This species was less abundant at Saranac Inn than the others of the genus mentioned as occurring there ; but I captured at random a number of specimens of both sexes. The female shown in pi. 22, fig, 2, exhibits a singular type of coloration for this genus. The wings were of a rich fla- vescent brown, with spots of black on a number of the antenodal cross veins. This specimen I captured among the wild raspberry bushes near the house of the station agent at dusk, June 27. Owing to the striking difference between the male appendages in this and the other species of the genus, there is probably no need here of a new description, notwithstanding that the original one in French seems as yet to be the only one, and it is not generally accessible in this country. HELocoRDULiA gen. nov. The two species constituting this genus, C. uhleri Selys and C. s e 1 y s i Hagen, have been included hitherto in the genus Neurocordulia. There is hardly another genus within the corduline series as here restricted, with which these have less affinity. A tabular statement of the differences between Helocordulia and Neuro- cordulia (as here restricted) with respect to wing venation will show the great discrepances for a single organ — the only one T have critically studied. CHARACTEE NEUROCOEDULIA HELOCOKDULIA Veins M4 and Cui divergent apieally with the cell rows between increasing from 2 to 5 convergent apieally with but two cell rows be- tween Stigma broad and slightly ob- lique narrow and very oblique at its ends] Antenodals of hind wing- five six Triangle of fore wing of three cells of two cells Triangle of hind wing of two cells open : no cross vein Apex of anal loop with a long posterior angle, and at least five cells resting against the distal margin squarely truncate or near- ly so, with but three cells on the distal end 496 NEW YORK STATE MUSEUM Helocordulia is most nearly allied to Tetragoneuria. There are however a few venational characters which readily distinguish the two genera. CHAEACTEE TETEAGONE0EIA HBLOCOEDULIA 2d cubito-anal cross vein absent nearly always present Under the stigma a single cross vein fol- lowed by a wide space two cross veins and more normal spaces Autenodal cross veins of the hind wing four or five six The anal loop is slightly wider and more oblique at the apex in Tetra- goneuria. T. spinosa has the antenodal cross veins spotted with fuscous much as in Helocordulia. The nymph of H elo cord ulia is peculiar among the known cor- duline nymphs in having dorsal hooks on segments 6-9 only, with some Fig. 21 Helocordulia, genitalia: x,v [$) and z (?) of H. uhleri Selys: a, b (ventral view), c ( ^ ) and (J ( $ ) of H. selysi Hag. of these distinctly cultriform, and in the extreme abbreviation of the ninth abdominal segment on the dorsal side, so that its dorsal length is less than half its ventral. The two species of the genus may be separated as images by reference to the figures herewith presented. The nymph is known for but one of these, H. uhleri, the only one apparently belonging to the New York fauna. AQUATIC INSECTS IN THE ADIRONDACKS 497 Helocordulia uhleri Selys 1871 Cor dull a uhleri Selys, Acad. Belg. (2) Bui. 21:274 1890 N euro c orduli a uhleri Beutenmiiller, Dragon flies vs mosquitos, p. 164 (listed from New York) 1895 Neuroeordulia uhleri Calvert, N. Y. ent. soc. Jour. 3:46 (listed from New York) This species was not uncommon in Little Clear creek on the hatchery grounds. Images were seen flying a few times about the banks of Little Clear pond close in shore and low above the water. They are so swift and agile, and their wings are so transparent that the eye follows them with difficulty. They are not very difficult to capture however, if one will place himself beside a regular " beat ", and bring his net up behind the dragon fly with a quick stroke when it is passing. I found the ima- ges showing no disposition to avoid me even after escaping a stroke of the net several times. Twice I saw three males chasing one another up and down Little Clear creek, and had little difficulty in capturing them. The nymph was not reared. Some of them, apparently about grown, were kept through the season without result. Apparently, the season for their transformation was over before any were found, There can be Fig. 22 Parts of nymph of Helocordulia uhleri Selys. a dorsal view of the head ; b labium, from within, details In part omitted on the right ; c a single tooth from the front border of the lateral lobe of the labium ; d dorsal view of the abdomen ; e lateral view of apex of abdomen, to show^ better the dorsal hooks scarcely a doubt, however, as to the correctness of the reference of them to this species, when one considers that the only other corduline observed here like this one in size was D . libera, which I reared. The nymphs live in the borders of the creek, mainly in the shallow places, filled with red-rotten vegetable debris — the haunts of the giant 498 NEW YORK STATE MUSEUM crane fly, Tipula abdominalis, and the phantom fly, B i 1 1 a c o - morpha clavipes, larvae. But little collecting was done in such net-clogging situations, and hence, but a few of the nymphs were obtained. A single cast skin was found on a stump in the edge of a boggy place in Little Clear outlet, about eight inches above the surface of the water. Nymph. Measures in total length 20 mm, abdomen 11 mm; hind emur6mm; width of head 5 mm, of abdomen 7 mm. Color brownish, due to copious incrustation in all my specimens, with no visible color pattern. Head compact, shghtly broader than long; eyes only moderately prominent, with parabolic curve on the anterior side ; antennae with segments about equal, the last, perhaps, a httle shorter and pointed; labium reaching posteriorly between the bases of the fore legs and hardly beyond them ; mentum triangular, channeled ; the median lobe rather prominent, dechned, fringed sparsely with short spinules along its fore margin; mental setae about 10 or 11, the fifth or sixth (counting from the side) longest ; lateral setae seven or six, when seven the basal one smaller than the others ; movable hook hardly longer than the setae, but much stouter ; lateral lobe with about seven low crenate teeth on its distal border, each armed with two or three graduated spinules. Prothorax with a prominent lateral process at each side of the dorsum and a similar anteriorly directed process above the fore coxa; legs slender and sparsely hairy ; tarsi with the first joint about half as long as the second, which about equals the third in length. Abdomen broadly oval, with dorsal hooks on segments 6-9, on 6 rudimentary, a mere low pointed tubercle, on 7-9 cultriform, largest on 8. Lateral spines on segments 8 and 9, a little larger on 9, short, triangular, sharp, those of 9 about one third as long as that segment, and about reaching the level of the tips of the appendages. Segment 10 is minute, annular, inserted into the apex of the ninth segment, which is less than half as long on its middorsal as on its midventral line ; superior and inferior appendages about as long as segment 9 above, laterals one third shorter. SOMATOCHLORA This genus is by far the largest in our corduHne fauna. I have set apart three species hitherto placed in it, and, with these aside, it still comprises about half of the subfamily. The species seem to be common only in high altitudes in the northern part of the United States, and in British America. In all my collecting I have observed but one species in flight. This species was S. e 1 o n g a t a , of which a few specimens were seen flying about the borders of Bone pond on Aug. 14. I obtained one nymph only of the species. That one was from Little Clear pond. From it I bred a fine male imago July 5. This seems to be the only specimen bred for all of our species ; and so diverse are the images among themselves that the nymphs may hardly be expected to conform closely to the characters of this one in details. I give herewith figures of the AQUATIC INSECTS IN THE ADIRONDACKS 499 genitalia of both sexes of the five species listed below. These are the characters most used in characterizing them, and are the ones most reliable in determining specimens. These figures show the appendages to be unusually well marked with individuality. The nymphs of this genus offer an open field for study by collectors in boreal latitudes. Four species, tenebrosa, walshii, linearis and el on gat a, are recorded from the state. To this I have nothing to add but a new locality for the last named, and a partial life history of it. One other species occurs farther southward, and is almost certain to be taken in this state eventually, and is therefore included among the species listed below. Somatochlora elongata Scudder Plate 21, fig. 13 1866 Cordulia elongata Scudder, Bost. soc. nat. hist. Proc. 10:218 1895 Somatochlora elongata Calvert, N. Y, ent. soc. Jour. 3:46 (listed from Ithaca) The few imagos I saw of this species were flying with great swiftness about the borders of Bone pond. The single nymph I found was taken rig. 23 Somatochlora elongata Scudd., end of abdomen ; d and e of male ; /of female from Little Clear pond, as stated above, and transformed July 5. A cast nymph skin was found later in the season on the north side of the outlet of Little Clear, sprawling on a bed of moss but a few inches above the water line. 500 NEW YORK STATE MUSEUM Nymph. Measures in total length 26mm; abdomen 15mm; hind femur 7.5 mm ; width of head 7 mm, of abdomen 9 mm. Body of the form ofCordulia, or slightly broader, sparsely hairy on appendages and margins; head with hind angles well rounded, the eyes moderately prominent ; labium as in Cordulia, but with 13 or 14 mental setae, of which the fifth or sixth (counting from the side) is longest, the four or five internal ones being quite minute ; lateral setae seven; teeth low, crenate, each armed with four or five graduated spinules. Abdomen oblong, with not very sharp lateral margins, most narrowed posteriorly on the ninth segment; lateral spines on the eighth and ninth segments, those of the ninth segment about one fourth as long as the body of the segment ; dorsal hooks on segments 4 to q, small and erect points on segments 4 and 5, larger and laterally flattened and nearly equal on segments 6-9, but without sharp decurved apices ; ninth segment about half as long on the middorsal as on the mid- ventral line, inclosing the annular tenth segment ; lateral appendages hardly shorter than the equal lateral and superior appendages. Somatochlora filosa Hagen 1861 Cordulia filosa Hageu, Synopsis Near. N. Am. p. 136 1893 Somatoclilora filosa Calvert, Am. ent. soc. Trans. 20:253 (descrip- tion) 1900 Somatochlora filosa Williamson, Dragon flies lud. p. 313 Fig. 24 Somatochlora filosa Hag., end of abdomen ; m and n of male ; o of female This species is recorded from New Jersey and southward, and is very likely to be met with in New York state eventually. Nymph unknown. AQUATIC INSECTS IN THE ADIRONDACKS 501 Somatochlora linearis Hagen 1861Cordulia linearis Hagen, Synopsis Neur. N. Am. p. 137 1893 Somatochlora linearis Calvert, Am. ent. soe. Trans. 20:253 (de- scription) 1897 Somatochlora linearis Calvert, N. Y. ent. soc. Jonr. 5 :'95 (listed from Oswego cc, and Grand Island N. Y.) 1900 Somatochlora lateralis Williamson, Dragon flies In d. p. 313 (de- scription) A species I have not met with. Its nymph is unknown. Fig. 25 Somatochlora linearis Hag. end of abdomen ; g and h of male ; i of female Somatochlora walshii Scudder 1866 Cordulia walshii Scudder, Bost. soc. nat. hist. Proc. 10 : 217 1897 Somatochlora -walshii Calvert, N. Y. ent. soc. Jour. 5:95 (listed from Keene Valley) Nymph unknown. i Fig. 26 Somatochlora walshii Scudd., s dorsal, and t lateral views of appendage of the male Somatochlora tenebrosa Say 1839 Libellula tenebrosa Say, Acad. nat. sci. Phil. Jour. 8 : 19 1861 Cordulia tenebrosa Hagen, Synopsis Neur. N. Am. p. 137 1895-97 Somatochlora tenebrosa Calvert, N. Y. ent. soe. Jour. 3:46 and 5 ; 93 (listed from New York, Clarence and Oswego co.) 1900 Somatochlora tenebrosa Williamson, Dragon flies Ind. p. 314 (description) Nymph unknown. 502 NEW YORK STATE MUSEUM For location of descriptions of other species of the genus, some of which are Hkely to be taken in this state when careful collecting is done, consult the three bibUographic lists mentioned on p. 431. Fig. 27 Somatochlora tenebrosa Say, end of abdomen, j and k of male ; I of the female (appendages omitted) CORDULIA There is a single species belonging to our fauna. Cordulia shurtleffi Scudder 1866Cordulia shurtleffi Scudder, Bost. soc. nat. hist, Proc. 10: 217 1871 Cordulia shurtleffi Hagen, Bost. soc. nat. hist. Proc. 15 : 377 This species seems not to have been recorded hitherto from New York state. It was common at Saranac Inn. A few imagos were observed flying about the hatchery grounds, and along the creek, but their favorite resort for foraging and sport was the edge of a boggy pond hidden in the deep woods — such a pond, for instance, as the one a quarter of a mile south of the station, or the one north of the outlet of Little Clear pond back of the cabins. I spent a few of the pleasantest hours of the summer collecting on the springy border of the pond first named, immersed to the knees in the sinking sphagnum moss, a floating islet of sphagnum, decked with beautiful orchids, cut off by a narrow strait of clear green water at my feet. The Cordulias would fly along this slrait between the islet and the moss on which I stood, and within reach of my net. There were generally a dozen or more about at a time, and one could be expected to traverse the strait every few min- utes— often enough to keep a collector interested. So fleet are they, however, and so artful at dodging a net that generally a good many minutes elapsed between captures. Their flight is as free and graceful as their coloration is beautiful. Rarely was one seen to alight, but oc- AQUATIC INSECTS IN THE ADIRONDACKS 5^3 casionally one would sweep out into the forest and disappear among the hemlocks. The nymphs obtained were gathered from a shaded trashy place in the edge of Little Clear pond and from Bone pond. They lie sprawling amid the trash after the manner of the better known Libellulas. I did not rear these nymphs, the season of their transformation being over, apparently, before I obtained any of them. I kept a few in a cage through the greater part of the season : nevertheless, there is not the slightest doubt as to their identity. They agree very closely with the nymphs of the European C. a e n e a Linn., with specimens of which I have compared them. Male nymphs show in the stretched skin of the superior appendage the forked tip of the inferior appendage of the imago. The nymphs, like the images, were in numbers second only to the Tet- ragoneurias among the Saranac Cordulinae. Nymph. Total length 21 mm; abdomen 12 mm; hind femur 6.5 mm; width of head 6 mm, of abdomen 7 mm. Body elongate, sparsely fringed with coarse hairs on the appendages, edge of frons, rear of head, and lateral margins of abdomen; color greenish brown marked with blackish brown as follows : a tranverse band across the head including the eyes (almost divided by the median yellow ocellus when the nymph is grown) an urceolate median band on the prothorax not attaining its front margin, and divided by a fine yellow median line; a broad oblique lateral yellow band extending from above the base of the fore leg to the middle of the hind wing; below the last, a narrower parallel stripe above the base of the hind leg ; a pair of sub- median rows of blotches on the abdomen extending posteriorly from beneath the tips of the hind wings; and rings on femora and tibiae. Head with the eyes laterally prominent and well rounded, hind angles obtuse and the hind margin slightly concave; no vertical tubercles; frontal ridge low obtuse; labium reaching posteriorly between the bases of the second pair of legs, triangular elongate, channeled above ; median lobe prominent, declined; mental setae about 14, regularly graduated in size, the fourth (counting from the side) longest; lateral setae seven ; movable hook hardly longer than the setae, nearly straight ; teeth about nine, low, crenate, increasing in breadth inferiorly, each with several spinules. Abdomen oblong, a little widened to the seventh segment, most narrowed apically on the ninth segment; loth segment annular, half as wide as the ninth, and one fourth to one third as long as the ninth is on its middorsal line ; ninth segment one half as long on the middorsal line as on the midventral ; appendages almost equal, the superior and the laterals successively a very little shorter than the inferiors, which are about as long as segment 9 is on its dorsal side; lateral spines on segments 8 and 9 very short (about one fifth the length of the body of the segments which bear them), but pyramidal. The first cast nymph skin was obtained June 16. The imagos were flying commonly throughout the month of July. 504 NEW YORK STATE MUSEUM DOROCORDULiA gcn. nov. Cordulia libera Selys, type The three species here separated from Somatochlora and placed in this new genus dififer from Somatochlora by a number of important venational and other characters, among which are the following : 1 The triangle of the fore wing is open : it is traversed by a cross vein in Somatochlora. 2 There are never more than two complete rows of cells beyond the triangle in the fore wings : there are more than two in Somatochlora. 3 The second cubito-anal cross vein (and, therefore, an internal triangle or sub- triangle) is wanting in the hind wing ; it is present in Somatochlora. 4 There is a long space beyond the single cross vein under the stigma: in Somatochlora the spaces are more nearly equal, and there are often two cross veins under the stigma. The Cordulia lintneri of Hagen may not belong here: in fact it may belong in the subfamily Libellulinae, I leave it here beside the species with which it has been associated pending farther study, and awaiting the discovery of its nymph. It will be found not to agree with characters 2 and 4 of the above statement. This genus is more closely aUied to Cordulia than to Somat- ochlora, but it differs from Cordulia by characters i and 2 as stated above, as well as by the lack of the deep bifurcation of the inferior appendage of the male which is characteristic of Cordulia. The nymph also, I found much more easy to distinguish from that of Somatochlora elongata than from that of Cordulia shurt- 1 e f f i. The nymph is known for the single species D. libera. Our imagos are readily separable into species by the following key : a Abdomen with segments 7 to 10 spatulately dilated libera aa Abdomen gradually and very moderately widened at apex h The articulations of the abdominal segments yellow le pida lb The articulations of the abdominal segments not yellow lintneri Dorocordulia libera Selys 1871 Cordulia libera Selys, Acad. Belg. (2) Bui. 21:262 1895 Somatochlora libera Calvert, N. Y. ent. soc. Jour. 3 : 46 (listed from the Catskill mountains) This dainty and beautiful corduline species was not uncommon at Saranac Inn. But few specimens were taken, because no special effort was made to get them. The imagos obtained were taken when flying with Cordulia shurtleffi about the borders of the bog ponds mentioned under the account of that species. They are less swift of AQUATIC INSECTS IN THE ADIRONDACKS 505 flight than that species, but they dash along shore on shining, transparent wings, dancing in and out of the Httle coves in the edge of the sphagnum fringe, and once in a while are seen resting on the tall summit of some pitcher plant flower. The one nymph I obtained was taken from the edge of Little Clear pond at the outlet, and was reared, transforming July 7. From that cast skin the following description of the nymph was drawn up. The Fig. 28 Dorocordulia, end of abdomen, o, b and c of D. libera Sel.; a;, j/and ^ D. lepida Hag. specimen is in the New York state collection at Albany. The study of this specimen, which was preserved and labeled by myself with such promptness and care as to preclude error or confusion of species among my specimens, reveals an error in Cabot's work on the corduline nymphs. The one he described asSom. libera, raised, can not have been of that species . I have not seen his specimen, but both his description and his figure disagree utterly with my specimen. They agree quite well with the nymph of Helocordulia uhleri, and I think they may have belonged to that species or to H. s e 1 y s i . Nymph. Total length 21 mm; abdomen 11 mm; hind femur 6 mm; width of head 5.5 mm, of abdomen 7 mm. Very similar to the nymph of C. s h u r 1 1 e f f i , but smaller, and with the black band across the head broader between the eyes, the eyes them- selves more prominent laterally, and the hind angles of the head more angulate; labium similar; lateral setae seven; mental setae 12-13, e^ch side, the fifth (counting from the side) longest, the others regularly grading up to it; abdomen similar, but the very rudiinentary dorsal hooks a little more prominent on the middle segments (perhaps a httle less obscured by tufted hairs about them) ; lateral spines longer on segments 8 and 9, about a third the length of their respective segments ; inferior appendages longer than the superior, which in turn is longer than the laterals. 506 NEW YORK STATE MUSEUM Dorocordulia lepida Selys 1871 Cordulia lepida Selys, Acad. Belg. (2) Bui. 31 : 264 1872-75 Cordulia lepida Hagen, Bost. soc. nat. hist. Proc. 15 : 270 and 18:60 1895 Somatochlora lepida Calvert, N. Y. ent. soc. Jour. 3 : 46 (listed from Albany) This species was originally described from specimens sent from Albany; it seems not to have been taken in the state since that time. Its nymph is unknown. Dorocordulia lintneri Hagen 1854 Emmons, Agric. N. Y. v. 5, pi. 15, fig. 1 Ccolored fig. : no name or description) 1878 Cordulia lintneri Hagen, Acad. Belg. (2) Bui , 45 : 187 1890 Cordiilia lintneri Hagen, Psyche, 5:272, pi, 1, fig. 10-17 (a full account) 1895 Somatochlora lintneri, Calvert, N. Y. ent. soc. Jour. 3 : 46 (listed from Center, Albany co.) But few specimens are known of this very interesting species, which has a distribution from New York to Saskatchewan. Its nymph is unknown. Subfamily libelujlinab This extensive group includes the commonest and best known of all our Odonata. The images are familiar figures above every pond and ditch, and by every roadside. The nymphs are less well known, not- withstanding their relative abundance, than in some of the smaller groups. Our tables which follow are the first to be given for American forms, and the descriptions also are entirely new, with the exception of the nymphs of P a n t a 1 a and T r a m e a, which alone have been described by Cabot. The following keys will serve for the separation of both nymphs and imagos. KEY TO GENERA Imagos a Triangle of the fore wings four-sided; anal loop poorly developed, not foot- shaped ~ Nannothemis p. 509 aa Triangle of the fore wing fully differentiated, three-sided; anal loop well developed and foot-shaped i Triangle of the fore wing with its front and inner sides meeting by an angle of about 100° ; the subtriangle without cross veins; the vein which bisects the anal loop straight Perithemis p. 511 AQUATIC INSECTS IN THE ADIRONDACKS 507 Triangle of the fore wing with its front and inner sides meeting by an angle of about 90°; subtriaugle divided into three or more cells; bisector of the anal loop sinuous c Triangle of the fore wing not placed distinctly beyond the level of the apex of the triangle in the hind wing; pterostigma with its ends parallel or not distinctly divergent d The sectors of the arculus (veins M1-3 and M4) in the fore wing more or less completely fused for a short distance beyond the arculus ; the triangle of the fore wing not greatly produced posteriorly, and (except in Celithemis) normally containing but a single cross vein, and followed by two or three rows of cells e Vein Cm of the hind wing departing from the triangle at the hind angle / Sectors of the arculus (veins M1-3 and M4) contiguous, but in- completely fused for a distance beyond the arculus; wings generally conspicuously spotted with yellow or reddish brown Celithemis p. 513 ff Sectors of the arculus in the hind wing distinctly fused for a distance beyond the arculus g Stigma short and thick, about twice as long as wide ; anal loop with a big heel, there being generally four cells between the bisector and the heel point ; face pure white Leucorhinia p. 516 gg Stigma more than three times as long as wide; anal loop generally with but two cells between the bisector and the heel point Sympetrum p. 519 ee Vein Cui of the hind wing migrated a little way up the outer side of the triangle, separating itself at a distance from the hind angle / With a single cross vein under the stigma, and a long vacant space before that cross vein Pachydiplax p. 526 ff With two cross veins under the stigma and the adjacent spaces more normal g With a single row of cells between veins M2 and Rs Mesothemis p. 527 gg With two rows of cells for a distance between veins M2 and Es Micrathyria p. 528 dd Sectors of the arculus in the fore wing contiguous, but not completely fused beyond the point of their departure from the arculus ; radial sector distinctly undulate (except in L a d o n a) ; triangle of the fore wing very much elongated posteriorly and narrow and generally traversed by two or more parallel cross veins, and followed by three to seven rows of cells e Vein Mia arising under the proximal fourth of the stigma; fore wings with the subtriaugle consisting of three cells, and the triangle followed by three rows of cells Ladona p. 528 ee Vein Mia arising under the middle of the stigma; fore wings with the subtriangle consisting of four to 11 cells, and the triangle usually followed by four to six rows of cells 5o8 NEW YORK STATE MUSEUM / Male -with no ventral hooks on the first abdominal segment ; female with the hind tibia a little longer than the hind femur; the sexes alike in wing pattern Libellula p. 530 ff Male with a pair of ventral hooks on the first abdominal segment ; female with the hind femur and tibia of equal length; wings dissimilarly colored in the two sexes Plathemis p. 536 cc Triangle of the fore wing placed beyond the level of the apex of the triangle of the hind wing; stigma with its inner end perpendicular, its outer end very oblique to the bordering veins; wings broad at base and pointed at apex d Kadial sector regularly curved; hind wings with a broad, basal colored band Tramea p. 537 M Eadial sector distinctly undulate; hind wings not covered at base by a broad colored band Pantala p. 539 Nymphs a Unknown.... Nannothemisi and Mi cr athyria aa With large, cultriform dorsal hooks on abdominal segments 3-9 ; eyes small and situated on the midlateral margin of the head and directed laterally Perithemis aaa With no dorsal hook on the ninth abdominal segment; eyes overspreading more or less the anterolateral margins of the head 6 Basal segment of the hind tarsus more than half as long as the second segment; lateral appendages of the abdomen not more than half as long as the inferiors (except in Libellula quadrimaculata); superior abdominal appendage regularly tapering to a point c Abdominal appendages strongly decurved; lateral spines wanting or extremely rudimentary Mesothemis cc Abdominal appendages straight or very slightly declined ; lateral spines evident on abdominal segments 8 and 9 d With no dorsal hooks at all ; abdomen smooth, depressed ; head twice as wide as long, with eyes very prominent laterally.. Pachydiplax dd Dorsal hooks present, at least on the middle abdominal segments e Abdomen ovate in outline, rather abruptly narrowed to the posterior end; hind margin of the eyes behind the middle of the head / Lateral spines long and straight ; abdomen not narrowed posteriorly before the eighth segment Celithemis ff Lateral spines shorter and more or less incurvate ; the abdomen more or less narrowed before the eighth segment g Dorsal hooks as long as the segments which bear them Leucorhinia gg Dorsal hooks shorter than the segments which bear them Sympe trum ee Abdomen lanceolate in outline, slowly narrowed to the pointed posterior end ; eyes capping the i)rominent anterolateral angles of the head, their hind margin generally before the middle of the top of the head ; body generally hairy 1 Discovered since this key was prepared, and described below under tlie account of the genus. AQUATIC INSECTS IN THE ADIRONDACKS 509 /The 10th abdominal segment with subcarinate lateral margins; appendages very long ; lateral setae 0-3 Lad on a ff The 10th abdominal segment shorter, cylindric ; appendages shorter ; lateral setae 5-10 g Head a little narrowed behind the eyes; front border of the median lobe of the labium entire L i b e 11 11 1 a gg Head not narrowed behind the eyes to the hind angles ; front border of the median labial lobe crenulate Plathemis yh BasaFsegment of the hind tarsus half as long as the second segment ; lateral appendages of the abdomen at least three fourths as long as the inferiors ; lateral setae 10 or more ; superior appendage of the abdomen suddenly contracted at its basal third, the dorsal two thirds forming a long slender point c Movable hook of labium long and slender, setiform ; teeth much broader than high; spines of the eighth segment one half longer than the ninth segment; superior abdominal appendage shorter than the inferiors T r a m e a CO Movable hook of the labium short, hardly longer than the teeth ; teeth higher than broad; spines of the eighth segment as long as the ninth segment; superior appendage equaling the inferiors Pantala NANNOTHEMIS There is a single species occurring within the state. Nannothemis bella Uhler 1857 Nannophya bella Uhler, Aead. nat. sei. Phil. Proc. p. 87 1861 Nannophya bella Hagen, Synopsis Neur. N. Am. p. 186 1867 Nannoph ya bella Packard, Am. nat. 1:311, pi. 9, fig. 6 1893 Nannothemis bella Calvert, Am. ent. soc. Trans. 20:260 (description) 1895 Nannothemis bella Calvert, N. Y. ent. soc. Jour. 3 : 48 (listed from Westchester co. and New York) 1900 Nannothem is bella Williamson, Dragon flies Ind. p. 327 This is apparently a somewhat rare species, I have not seen it alive. It is known to be distributed from Quebec and Indiana to Florida. Since the foregoing key was prepared its nymph has been discovered by Mr R. Weith near Elkhart Ind. and he has published some notes on the life history of the species and I have described the nymph (Can, ent, 1901. 33:252-255). Mr Weith's notes are abstracted below, and my own description and figure are appended. This species occurs in very restricted areas (50 yards in length by 25 yards in width from margin of the lake) in two places near Elkhart Ind. Unlike most other Odonata, the images do not fly higher than a few feet above the ground, preferring to alight on marsh grasses and bask in the sunshine, where numerous small Diptera suitable for food 510 NEW YORK STATE MUSEUM hover over the Httle stagnant pools. Nymphs were first found in small holes in the almost dry marsh land, too small to allow the use of a net and containing but a few inches of water. A larger number was obtained later from debris deposited in the marsh during high water and still sub- merged a few inches. Removed from the water the nymph clings closely to the debris of exactly its own color, and does not stir even after letting this dry; so it is very hard to see and a difficult subject for collection. Fig. 29 N anno them is bella Uhl. Nymph, labiallobe of nymph, and eggs The females oviposit in the shallow places where the nymphs live, in temporary water of one to two inches depth, and very warm. The female dips the tip of her abdomen to the surface after the manner of all Libellulines, but only about three or four times ; then rests; then repeats. The eggs are creamy white turning dark in a short time, and with scanty gelatinous envelop. (From the account by Mr Weith) AQUATIC INSECTS IN THE ADIRONDACKS 5II Nymph, (fig. 29) Fully grown, measures in total length of body 10 mm; abdomen 5.5 mm; hind femur 3.5 mm; width of head 3.5 mm, of abdomen 4 mm. Color almost uniform tawny yellowish brown, paler below and on the sutures, more or less completely obscured by adherent vegetable debris. Body moderately hairy on lateral margins, specially hairy toward the end of the abdomen. Head compact, one third wider than long, scurfy hairy above excepting a pair of bare spots near the hind margin, with prominent hemispheric, eyes covering the anterolateral angles, narrower behind the eyes with parallel sides, rounded hind angles, and almost straight hind margin. Antennae shorter than the head is long, seven-jointed, with scattering hairs along the distal joints. Labium extending posteriorly between the bases of the fore legs ; median lobe broadly triangular, half as long as wide, rounded on tip, with two spinules close together just before the tip, and several others each side along the front border farther apart; raptorial setae on the mentum, 10 each side, the fourth or fifth (counting from the side) longest, the three innermost ones quite small; lateral labial lobes ample, with six raptorial setae, and a spinule at the base ; hook straightish to the slender slightly curved tip, hardly longer than the setae, but much stouter ; teeth almost obsolete, bispinulose. Prothorax with prominent spiracles; legs hairy, specially the tibiae externally; tarsal claws not strongly incurved; second tarsal joint one half longer than the first, and the third one half longer than the second; wings reaching well on the sixth abdominal segment. Abdomen somewhat depressed, oblong, widest on the sixth segment, the ninth segment as wide as the second ; narrowed with extraordinary abruptness on the loth segment, which is almost included within the apex of the ninth. No dorsal hooks at all ; in their places are tufts of a few long hairs, and whitish spots in the ante-apical membrane of the segments. Lateral spines on segments 8 and 9, hookUke, starting outward at base, and incurved at tip, on eight one half the length of the segment, on nine, a little longer than on eight. Hairs on the apical carinae well developed, specially so on segment nine, which they com- pletely incircle, constituting a long fringe which completely overhangs the loth segment and the appendages. Appendages about as long as the ninth segment is on its slightly shorter dorsal side ; lateral appendages a third shorter. Since the discovery and description of the nymyh of Tachopteryx t h o r e y i Selys by Messrs Graf and Williamson, last year, this species has remained the most important discovery to be made. It is our only representative of that singular group of Libelluline genera which Karsch called the Nannophyae.^ Mr Weith's zeal and industry have brought this nymph to light, and there now remains of all the genera of Odonata of the northern United States and Canada but two in which no nymph are known, and they are Goraphaeschna and Micrathyria. PERITHEMIS There is a single species occurring within the state. ^ Ent. Nachr. 15 ; 245-63. 512 NEW YORK, STATE MUSEUM Perithemis domitia Drury Plate 24, fig. 3 and 4 Amber wing I use the above scientific name in this place without having entered into the question of synonomy — a question for the determination of which. I have no adequate material. Domitia is the name that has heen used hitherto in most American descriptive papers. Dr Haj^en regarded ten era and tenuicincta Say, chlora Eambur, metella Selys, Siud iris Hagen, as synonyms of domitia. Forms like those occurring in New York state were described by Say (1839) under two names, tenuicincta (^) and tenera (5)- Should these be ranked as a species distinct from domitia the latter name, having precedence of position in Say's list, would be the name for the species. Hagen's Synopsis of the Odonata of America'^ and Kiiby's Cata- logue of the Neuroptera Odonata 2, represent the extreme views. 1773 Libel lula domitia Driiry, Illus. exotic ent. v. 1, pi. 47, fig. 4 1861 Perithemis domitia Hagen, Synopsis Neur. N. Am. p. 135 1893 Perithemis domitia Calvert, Am. ent. soc. Trans. 20:264 (descrip- tion) 1895 Peritliemis domitia Calvert, N. Y. ent. soc. Jour. 3:48 (listed from Westchester co.) 1898 Perithemis domitia Needham, Outdoor studies, p. 59, fig. 58 ( 5 ) and 59 ( $ ) 1899 Perithemis domitia Kellicott, Odon. Ohio, p. 112 (description) 1900 Perithemis domitia Williamson, Dragon flies Ind. p. 317 (descrip- tion) This is a pretty, little brown species, with amber tinted wings. It is apparently not common in New York state, having been taken as yet only in the vicinity of New York city. I studied the species in Gales- burg 111., in 1895, and there worked out its life history. It appears on the wing about the end of May, and flies through June. Its flight is rather weak, and a bit clumsy and slow. When over water it habitually avoids the altitude of the larger and stronger species, keep- ing down nearer the surface. It is very sensitive to cloudiness and moisture, being seldom seen in flight except when the sun is shining. The female is sometimes held by the male while ovipositing, but I have seen her oftener unattended, dropping her eggs on bits of floating dead pond scum by many successive dips made at very nearly the same spot. When a female was taken in hand and " dipped " to the surface of water in a tumbler, lo to 20 eggs were liberated by her at each de- scent. 1 Bost. soo. nat. hist. Proc. 1875. 18 :82-83. 2 1890, p. 10. AQUATIC INSECTS IN THE ADIRONDACKS 513 The egg (pi. 19, fig. 8) is oblong oval, at first white, turning brownish gray after a few hours ; its surface is closely beset with minute tubercu- late granulations. The gelatinous envelop is scanty. The nymphs clamber about over trashy submerged vegetation ; they climb well, but swim very poorly. They are cleaner and less sprawling than the Libellulas. The nymph goes no farther from the edge of the water to transform than is necessary to find a suitable place — generally but a few inches. Nymph. Total length 15 mm; abdomen 9 mm; hind femur 5.5 mm; width of head 4.5 mm, of abdomen 6 mm. Head wider than long, slightly concave behind, widest across the rounded eyes, which are at the middle of its length; labium (fig. 8A) short, not extending posteriorly beyond the bases of the first pair of legs; lateral setae five; mental setae about nine or 10, the two innermost ones minute and out of hne with the others, the fifth (counting from the side) longest ; teeth crenate, well marked, each armed with several spinules ; hook short, little curved, differing much from the setae behind it in its greater thickness and less length. Femora twice ringed with black ; wing cases extending over the sixth abdominal segment. Abdomen (fig. 8C) broad, depressed, triquetral, in outline oblong oval ; lateral spines on segments 8 and 9, short ; dorsal hooks on segments 3-9 ; these form a regularly descending curve, and, viewed laterally, look like a segment of a circular saw; superior and inferior appendages equal; the laterals half as long. celithemTs Two species of this genus, C. e p o n i n a and C. e 1 i s a, are known from this state, and a third, C. o r n a t a, may be looked for toward the coast. These are three of the most beautiful among all our smaller species. Their colors are shades of black, red, yellow and brown ; and the wings in all have a distinct color pattern. The nymphs are known for the two species recorded from the state. They agree in having smooth bodies with depressed abdomen and long lateral spines. The head is wider than long, widest across the very prominent eyes, which at their sides are almost angulate, they project so sharply; the labium is very large, and has numerous very long and slender raptorial setae, and a pair of very long thin movable hooks ; the teeth are almost obsolete, but the spinules which arm them remain. The abdomen is scarcely narrowed posteriorly before the ninth segment, so that the side margins seem to be continued posteriorly in the long spines of that segment. The superior appendage is one fourth, and the lateral appendages are one half shorter than the inferiors. Images and the two known species of nymphs may be separated by the following key. 514 NEW YORK STATE MUSEUM KEY TO SPECIES OF CELITHEMIS Imagos a Wings spotted with brown beyond the nodus & Expanse of wings at least 65 mm ; a band of brown on the wings at the nodus reaching almost across the wings eponina Tab Expanse of wings not over 60 mm ; a small rouuded spot of brown just beyond the nodus elisa aa Wings with no brown markings except at base ornata Nymphs a Unknown ornata aa Dorsal hooks well developed on abdominal segments 4 to 7, longest on segment 6 and sharp ; lateral spines of the ninth segment reaching level of the apices of the iuferior appendages ; lateral setae eight or nine eponina aaa Dorsal hooks weakly developed on segments 5 to 7, short, but pointed ; lateral spines of the ninth segment attaining only the level of the tip of the superior appendage; lateral setae seven elisa Celithemis eponina Drury Plate 24, fig. 2 1773 Libellula eponina Drury, Tllus. exotic ins. v. 2, pi. 47, fig. 2 1861 Celithemis eponina Hagen, Synopsis Neur. N. Am. p. 147 1875 Celithemis eponina Hagen, Bost. soc. nat. hist. Proc. 18:66-67 1893 C elithemis eponina Calvert, Am. ent. soc. Trans. 20:261 (des- cription) 1895-97 Celithemis eponina N. Y. ent. soc. Jour. 3:48 and 5:94 (listed from Westchester co. New York, Lake Bluff, Wayne eo.) 1898 C el i them i s eponina Needham, Outdoor studies, p. 60, fig. 60, (habits) 1899 Cell themis eponina Kellicott, Odon. Ohio, p. 103 1900 Celithemis eponina Williamson, Dragon flies Ind. p. 318 This beautiful skimmer is abroad about the latter end of June and the first weeks of July in our latitude. It frequents the borders of ponds and neighboring grassy slopes, and sometimes when foraging, it is carried far from water by the winds. Its flight is not the swiftest or the most continuous, and there is a flutter to it suggestive of the flight of a butterfly. So far as I have observed, the female in ovipositing is held by the male, and both are apt to be seen on windy days when other species are in shelter, dipping to the surfaces of foaming waves, far out from shore. The eggs are better distributed than in most related species, and, pos- sibly for this reason, they seem to be somewhat fewer, and of larger size. Each egg is rotund oblong, whitish at first, soon turning yellowish. AQUATIC INSECTS IN THE ADIRONDACKS 515 Nymph. Total length 21 mm; abdomen 12.5 mm; hind femur 6 mm; width of head 6 mm, of abdomen 7 mm. To the foregoing generic characterization of the nymphs of C el i t h e- m i s and to the statement of the characters made for this species in the table, It need only be added here that in this nymph there is a blackish band between the eyes, and the femora are ringed with the same color ; the abdomen is widest across the sixth segment, beyond which the sides seem scarcely narrowed to the tips of the lateral spines of the ninth segment; the lateral margins of segments 8 and 9 are conspicuously spinulose serrate. The nymphs clamber about on submerged objects, and climb up stumps, etc., at the bank to transform, going but a little way, usually not farther than a foot. Celithemis elisa Hagen 1861 Diplax elisa Ha^en, Synopsis Near. N. Am. p. 182 1867 Diplax elisa Packard, Am. nat. 1: 311, pi. 9, fig. 5 1862 Celitliemis elisa Walsh, Acad. nat. sci. Phil. Proc. p. 400 1875 Celithemis elisa Hagen, Bost. soc. nat. hist. Proc. 18 : 67 1893 Celithemis elisa Calvert, Am. eut. soc. Trans. 20:261 (description) 1895 Celithemis elisa Walsh, N. Y. ent. soc. Jour. 3 : 48 (listed from Long Island, New York and Ithaca) 1899 Celithemis elisa Kellicott, Odon. Ohio, p. 104 (description) 1900 Celithemis elisa Williamson, Dragon flies Ind. p. 318 (description) This species has about the same seasonal range as the preceding. E. B. Williamson has written {loc. cit. p. 319-20) very interestingly of the habits of the imago, as follows. This species may often be found resting on the inflorescence of some of the rushes, preferably the bulrush, Scirpus lacu s tri s , growing in the shallow waters of our lakes. So perched on a swinging rush, they have a wide view of what is going on about them and at the same time are inconspicuous, harmonizing well with the dingy brown of the over ripe flowers to which they cling. From this vantage ground they make sudden dashes at passing Diptera and smaller dragon flies, often returning to the identical sedge time and again. Each is the proprietor of a par- ticular locality. When one encroaches on the hunting territory of an- other, he is quickly hustled away by the rightful and irate owner . . . The females are more retired, and are usually found among the sedges back from the water's edge. Nymph. Measures in total length 14.5 mm; abdomen 8 mm; hind femur 4 mm ; width of head 4 mm, of abdomen 5 mm. These measure- ments are taken from a rather small nymph skin, from New England — a bred specimen, and the only specimen in my possession. I should expect the typical elisa nymphs from localities farther west would be of somewhat larger size. 5l6 NEW YORK STATE MUSEUM ? Celithemis ornata Rambur 1842 Libellula oruata Rambur, Ins. Neui*. p. 96 1861 Diplax ornata Hagen, Synopsis Neur. N. Am. p. 182 1861 Diplax amanda Hagen, Synopsis Neur. N. Am. p. 183 1893 Celithemis ornata Calvert, Am. ent. soc. Trans. 20: 261 (description) Maine to Florida along the coast; not as yet recorded from this state. Nymph unknown. LEUCORHINIA A single species, the common L. intacta, has been recorded hitherto from this state. A second species is now added, L. glacialis, which was common at Saranac Inn. I have bred, and describe below the nymphs of both these species, as well as the female imago of the latter species which has not hitherto been known. Imagos of this genus flit about the vegetation of marshy shores, or go foraging along weedy roadsides near by. Their flight is not long sus- tained, consisting mainly of short sweeps from one resting place to another. The nymphs clamber among the submerged stems of aquatic plants. They are smooth, clean, and generally show a definite and well marked color pattern, of brown on a greenish ground, harmonizing well with the environment of mixed green and dead stems. They agree in having the eyes laterally prominent, but a little less so than in Celithemis, lacking the tendency toward the lateral angulation seen in that genus, in having a larger number of lateral setae on the labium (lo-ii), in having the abdomen a httle narrowed beyond the sixth segment, and the dorsal hooks on segments 5-8 sharply bent posteriorly just above their bases, and long — as long as their respective segments — and very sharp. Our two species mdy be separated by the following keys. KEY TO SPECIES OF LEUCORHINIA Imagos a Inferior appendage of the males bifurcated ; generally, a yellow twin spot on the dorsum of the seventh abdominal segment; females with the two lobes of the vulvar lamina long and slender, each much longer than wide intacta aa Inferior abdominal appendage of the male not bifurcated, with only a shallow angular notch in its end, no twin spot on segment 7 ; valvar lamina of the female with its two lobes little developed, much shorter than broad glacialis Nymphs a Dorsal hook of the eighth abdominal segment directed straight posteriorly at its apex ; lateral setae 10 intacta aa Dorsal hook of the eighth abdominal segment strongly declined at its tip; lateral setae 11 resting on the dorsum of the ninth segment glacialis AQUATIC INSECTS IN THE ADIRONDACKS 51/ Leucorhinia intacta Hagen White face 1861 Diplax intacta Hageu, Synopsis Neur. N. Am. p. 179 1890 Leuc orli in i a i n t ae t a Calvert, Am. ent. soc. Trans. 18:39, pL 5, fig. 1, 7-9 1890 Leucorliinia intacta Hageu, Am. ent. soc. Trans. 17:235, pi. 10, fig. 6, 8, 15, 16 and 23 1893 Leucorhinia intacta Calvert, Am. ent. soc. Trans. 20:262 1895-97 Leucorhinia intacta Calvert, N. Y. ent. soc. Jour. 3;48 and 5:94 (listed from Center, Keeseville, Ithaca, Westchester co., Croton on Hud- son, Niagara river, etc.) 1899 Leucorhinia iotacta Kellicott, Odon. Ohio, p. 106 (description) 1900 Leucorhinia intacta Williamson, Dragon flies Ind. p. 321 (descrip- tion) This species was not observed at Saranac Inn, but it is very common at Ithaca in the marshy flats below the city, at the head of Cayuga lake and in the shallow ponds between McLean and Freeville N. Y., where I have collected the nymphs in great numbers. I have observed the female images ovipositing in two quite different ways : descending and striking the water with the tip of the abdomen while in flight after the manner most common among Libellulidae, and at rest on some vertical stem at the surface of the water, plying with the tip of the abdomen just below the surface. In both cases the female was unattended by the male. Nymph. Total length 17.5 mm; abdomen 10 mm; hind femur 5 mm; width of head 5 mm, of abdomen 6.5 mm. In coloration the body shows generally very distinctly the following marks, besides others less distinct and constant. There is the usual black band across the head including the eyes, and the usual rings of brown are on the legs, and oblique stripes on the sides of the thorax; there is a pair of black bands emerging from beneath the tips of the wing cases, and extending to the sides of the loth abdominal segment; there is a submedian, double row of round dots on the ventral side, running the length of the abdomen ; and between these and the lateral margins of the abdomen there are two blackish, interrupted bands, one on each side. The labium is ample, and has 10 lateral setae, and about 13 mental setae, of which the sixth (counting from the side) is longest; the teeth are obsolescent, but still distinctly crenate in form, and armed with sev- eral spinules each ; the abdomen is widest across the sixth segment, narrowing slowly to the eighth segment, and then suddenly narrowed at the ninth; the lateral spines of the eighth segment surpass the middle of the ninth segment on its dorsal side; those of the ninth segment about attain the level of the tip of the superior appendage; the lateral append- ages are half as long as the inferiors, and these exceed the superior a little; dorsal hook of the third segment very minute, erect; that of the fourth segment erect also but larger, the remaining hooks of more nearly equal size, laterally flattened, and above their bases strongly bent pos- teriorly, the tip of the hook of the eighth segment being scarcely more declined than the tip of the hook of the segment before it. 5l8 NEW YORK STATE MUSEUM Leucorhinia pflacialis Hagen Plate 10. 1890 Leuc orhini a glacialis Hagen, Am. ent. soc. Trans. 17:234, pi 10, fig. 3 and 14 This species has been known hitherto from a few male specimens col- lected at Cape Breton, N. S., London, Ont.; Michipicoten on Lake Superior; Reno, Nev. ; and in the White mountains of New Hampshire. It has not been recorded from New York state, but I found it common at Saranac Inn. During the irrst week or two of adult Hfe, before age and pruinosity have obscured its remarkably fine coloration, it is a singularly beautiful insect. One who sees only preserved specimens would not sus- pect this however, for in such, faded browns have replaced the ruby red color of the males and the brilliant yellow of the females. I well remember with what dehghted surprise I greeted my first specimen. It was a young male, with a brilliant red body phalerate with jet black, a flaves- cent tinge beyond the basal markings of the wings, a rich red-brown stigma, with a touch of yellow on the costa either side of it, and a face with the whiteness and subopaqueness of fine china. That specimen was captured beside the Inn road in the last week of June ; soon after, ward I found plenty of them — females as well — about the bog pond that lies near this road south of the station ; they were flying with C o r d u 1 ia shurtleffi, Dorocordulia libera, and Lestes eurina — a group of rare beauties. Early in July I found them commonly about the outlet of Little Clear pond, and there obtained nymphs (which later were reared), saw the females ovipositing and obtained the eggs. Female imago (hitherto undescribed; pi. lo, fig. 3). Length 34 mm ; abdomen 23 mm; hind wing 25 mm. Similar to the male, with only the middle half of the labium black, the sides white (I have a small male that is so, also); face opaque white. Thorax and basal segments of the abdomen brilliant yellow in life, phalerate with black ; the middorsal thoracic stripe of black con- stricted above, dilated below ; a short, not very distinct, isolated humeral stripe of black; complete stripes that are broad and irregular on the humeral and third lateral sutures, and an oblique lateral stripe crossing the midlateral suture and joining the humeral stripe; a black mark on the mesothoracic spiracle; dorsal and lateral yellow areas almost envel- oping the basal abdominal segments, but isolated on the first and second segments, fused on the third, which is all yellow except an apical ring and a mark at each side below; there is a yellow dorsal mark on the fourth segment, and there are dorsal yellow triangles on segments 5-7 ; there is also a lateral yellow basal triangle on each side of the fourth segment. The wings have the basal marking and the yellow AQUATIC INSECTS IN THE ADIRONDACKS 519 points at the ends of the stigma as in the male, but they are more flaves- cent in their basal half. The vulvar lamina is very short, being very much broader than long, with a quadrangular excavation in the middle separating its two low lobes widely; far beyond the apices of these two lobes and near the middle of the venter of the ninth segment there is a pair of minute, erect quadrangular prominences ; the apical margin of the venter of the ninth segment is very convex. I observe in my specimens considerable variation in the size of the males : 32 to 37 mm in length ; the genitalia, however, are quite constant in form and agree well with the figures by Hagen cited above. Nymph. (PI. lo, fig. i, 2) Total length 18 mm; abdomen 10 mm; hind femur 5.5 mm; width of head 5.5 mm, of abdomen 6.7 mm. Unfortunately, I obtained but few nymphs, and reared them all, so that I have nothing left but the cast skins for description; these do not preserve well the nymphal color pattern when dry ; there is enough of it left to show that the coloration is similar to that of L. in tact a de- scribed above, though probably not so well marked. The nymph is so very similar to the preceding, it is hardly worth while to repeat the de- scription in detail. The more salient points are as follows. The lateral setae are 11; the mental setae about 13, of which the sixth (counting from the side) is longest; the lateral spines of the eighth abdominal seg- ment are a trifle longer than half the dorsal length of the ninth segment , the lateral spines of the ninth segment attain to the level of the tips of the inferior appendages, which are scarcely longer than the superior ap- pendage. The dorsal hooks are as described above for L. in tact a; excepting that the apex of the hook of the eighth segment is declined so that it rests at its apex on the dorsum of the ninth segment. This last and most distinctive character between the two species is shown by some nymphs which were collected for me by Chester Young at EUenville N. Y., May 30, 1897. These, from the Catskills, may be the nymphs of L. glacial is also; but, among so many species so much alike, and so few of them bred, they can not be so determined with certainty as yet. The eggs are roundish oval, with a moderate investment of gelatin. They are white at first, but turn a pale lemon yellow after a number of hours. They are dropped by the female in flight in the little clear pools along shore, strewn over the bottom with hemlock leaves. SYMPETRUM This large genus is represented in New York state by seven nominal species, and an eighth is regional. Most of these species are exceed- ingly common along marshy shores and in wet meadows. The imagos travel often considerable distances from the water, and at the proper season are met with on upland meadows very commonly. Because of their famihar habits and their strikingly brilliant red coloration, they are very well known. The nymphs are very like those of Leucorhinia, specially the species placed first in our list; but they are (except S. corruptum) 520 NEW YORK STATE MUSEUM of smaller size and have the dorsal hooks of the abdomen less developed. The following keys will serve for the separation of our imagos and also of the nymphs as far as I have been able to find any differences between them. albifronB coBtifemm Fig. 30 Genitalia of the New York species of Sympetrum (excepting S. cor rup turn Hagen); first column, external view of the male genital hamule ; second column, lateral view of male ab- dominal appendages ; and third column, ventral view of vulvar lamina of the female, for the species named In the figure KEY TO SPECIES OF SYMPETRUM Iniagos a Witli a median transverse ridge incircliug the fourth abdominal segment (in addition to the normal apical ridge) corruptum aa With no such added ridge on the fourth abdominal segment & Superior appendages of the male with a prominent median inferior tooth, having some denticles before it; vulvar lamina of the female divided by a median cleft into two pointed lobes AQUATIC INSECTS IN THE ADIRONDACKS 521 c Tibiae and tarsi yellow externally ; tbe black of the abdominal segments tending to form apical rings albifrons cc Tibiae and tarsi wholly black; the black of the abdominal tending to form apical lateral triangles d Wings with the basal half (or somewhat less) flavescent ; branches of the genital hamule of the male inclosing an angular notch; vulvar lamina of the female with its lobes short and sharply recurved up- ward, their apices meeting the venter of the ninth segment vertically assimilatum dd Wings flavescent only at the extreme base ; branches of the genital hamule of the male inclosing an oval or a rounded notch ; vulvar lamina of the female with appressed lobes which meet the venter of the ninth segment more obliquely e Branches of the genital hamule of the male inclosing an oval notch, the outer about twice as stout as the inner, about equally curved; the vulvar lamina of the female with its sides regularly sloping rubi cundulu m ee Branches of the genital hamule of the male inclosing a short rounded notch, the inner branch more sharply incurved, the outer about four times as thick as the inner ; the vulvar lamina of the female some- what contracted at about midway its length, the sides more con- vergent in the basal half obtrusum 66 Superior abdominal appendage, of the male without a prominent inferior median tooth, but only with small inferior denticles of about equal size ; vulvar lamina of the female not cleft c Wings with the basal half flavescent semicinctum ec Wings flavescent only at the extreme base d Femora and tibiae entirely yellow -- vicinum dd Femora and tibiae marked with black on the sides costiferum Nymphs'^ a Dorsal hooks of abdominal segments 6-8 long and sharp, about as long as their respective segments & Lateral spines straight on both outer and inner margins costiferum 1 The nymphs of albifrons and corruptum are unknown; that of the former species Is likely to be of the type of the nymph of rublcundulum. I give a figure (pi. 25, fig. 1) of a nymph from southern California of S. illotum, the nearest ally of corruptum. The nymph of corruptum will probably be of this type. I have nymphs of rubicundulum raised at Ithaca, of obtrusum, raised at Lake Forest 111., and of assimilatum raised at Saranac Inn. Between the nymphs of rubicundulum . and obtrusum I find only a scarcely perceptible difference in size, that of obtrusum being a little smaller, in the bred specimens. Both these are a very little smaller than assimilatum; and I note that In the bred specimens the dorsal hooks on the fourth and fifth abdominal segments (hidden between the wing cases) are larger and more nearly equal in size in assimilatum, smaller and more unequal in size and paler in the other two. These differences are so slight and have been studied in so few specimens that I have not thought best to introduce them as yet into the table. As to the images of these three nominal species, I know of no absolutely constant differences either in size, coloration, structure, distribution or habits that will In every case distinguish be- tween them. The typical rubicundulum is of course, intermediate between the other two. I have examined hundreds of specimens of each, and say unhesitatingly tliat they intergrade eoju- pletely; nevertheless, it is convenient to recognize the three forms, and practically, there is little difficulty generally in distinguishing between them. I have therefore listed them separately. 522 NEW YORK STATE MUSEUM M Lateral spines of the ninth segment straight on the inner, but incurvate on their outer margins c Lateral spines of the eighth segment thin, flat and sharp, attaining the level of the apical margin of the ninth segment on the middorsal line vieinum cc Lateral spines of the eighth segment stouter, their tips hardly surpassing the middle of the dorsum of the ninth segment semi cin turn aa Dorsal hooks of abdominal segments 6-8 shorter than the segments bearing them, andlesspointed. assimilat um, r ubieundulum, obtrusum Sympetrum costiferum Hagen Figure 30 1861 Diplax costifera Hagen, Synopsis Neur. N. Am. p. 175 1895 Diplax costifera Calvert, N. Y. ent. soc. Jour. 3:48 (listed from Amherst) This species came up quite unexpectedly in one of my breeding cages at Saranac Inn. I had collected a number of nymphs from the shore of Little Clear pond near the outlet, and put them in this cage, supposing them to be of one species; they yielded at transformation imagos of S. vieinum, but one nymph yielded a fine male specimen of this species. It is the one from which the characters stated herewith are drawn. No imagos were seen at large. This one appeared on August 8. The cast skin was left in a somewhat collapsed condition, so that it is hard to measure accurately; but the measurements are, as nearly as I can make out, as follows: total length 14.5 mm; abdomen, g mm; hind femur 5 mm ; width of head 5 mm, of abdomen, 6 mm. The eyes are a trifle less prominent than in S. vieinum; there are II lateral setae, and about 13 mental setae, of which the fifth, counting from the side, is longest, the movable hook is somewhat shorter and thicker than in S. vieinum, and the teeth are more nearly obsolete; the lateral spines of the eighth abdominal segment are about half as long as is that segment; those of the ninth segment are much longer, slender, straight on both margins, and their tips scarcely attain the level of the tips of the appendages. The superior appendage is scarcely shorter than the inferiors, but these laterally are less than one half as long. Sympetrum vieinum Hagen Figure 30 1861 Diplax vicina Hagen, Synopsis Neur. N. Am. p. 175 1893 Diplax vicina Calvert, Am. ent. soc. Trans. 20:264 (description and figure) AQUATIC INSECTS IN THE ADIRONDACKS 523 1895-97 Diplax vicina Calvert, N. Y. ent. soc. Jour. 3 : 48 and 5 : 94 (listed from Lake St Regis, Keesevilie, Dobbs Ferry, New York, Ithaca, Cats- kill mouutains, Schoharie, Piseeo lake and Bnifalo) 1899 Diplax vicina Kellicott, Odon. Ohio, p. 110 (description aud figure) 1900 Diplax vicina Williamson, Dragon flies lud. p. 323 This pretty, little, yellow-legged, autumnal species is likely to be found about every marsh-bordered pond in the state. It flits about the shore vegetation and is not at all difficull to capture with a net. At Cascadilla pond near Ithaca I have watched the females ovipositing on beds of wet and matted dwarf club-rush, sometimes alone, but oftener held by the male, both descending together and rising every time the tip of the ab- domen was brushed against the wet mats. Some eggs obtained in Sep- tember at Ithaca hatched the following January, having been kept the Avhile in a laboratory of the normal temperature. Doubtless, under nor- mal conditions they do not hatch before spring. Nymph. Total length 13 mm; abdomen 8 mm; hind femur 4.5 mm; width of head 4.5 mm, of abdomen 5 mm. The eyes are a little more prominent laterally than in other members of the genus; the lateral setae are nine; mental setae about 12 or 13, the fifth (counting from the side) longest; the movable hook is exces- sively long and slender; the superior appendage is one third shorter than the inferiors, and the laterals less than one half as long as the inferiors. At Saranac Inn, the nymphs were found at the north side of the outlet of Little Clear pond, on the shelving bank behind the hummock of cat- tails. They are rather daintily colored with bands of black across the head, including the eyes, around the femora, and across the middle of the abdominal segments. They clamber about amid the semiaquatic vegetation. Sympetrum semicinctum Say Figure 30 1839 L i bell ul a semicincta Say, Acad. nat. sei. Phil. Jour. 8 ; 27 1861 Diplax semicincta Hagen, Synopsis Neur. N. Am. p. 176 1893 Diplax semicincta Calvert, Am. ent. soc. Trans. 20:263 (descrip- tion and figure) 1895 Diplax semicincta Calvert, N. Y. ent. soc. Jour, 3:48 (listed from Ithaca, Staten Island, Westchester co.) 1899 Diplax semicincta Kellicott, Odon. Ohio, p. 110 (description and figure) 1900 Sympetrum semicinctum Williamson, Dragon flies lud. p. 324 (description and figure) This species, which I have observed at Ithaca, and have bred in Illinois, did not appear at Saranac Inn. It is quite like the others of the genus. I have observed the female ovipositing alone in muddy pools among dead smartweed stems on a mud flat beside a pond. 524 NEW YORK STATE MUSEUM Nymph. (PI. 25, fig. 2) Of much the same form as that of S. vie in um, but a httle larger (at the time of writing this 1 have not my specimens at hand for reference, and can not therefore give the exact measurements; I have all the other details carefully recorded in note and drawings, but the measurements have been accidentally omitted) ; the eyes are laterally prominent, but well rounded; lateral setae nine; mental setae about 12, of which the fifth (counting from the side) is longest; the dorsal hooks on the fourth and fifth abdominal segments are less than one third as large as those on the three following segments ; the superior abdominal appendage is one fourth shorter and the laterals are one half shorter than the inferiors ; the spines of the ninth segment surpass the apices of the superior appendage, and are strongly incurved, and spinulose serrate on their exterior margins. Sympetrum assimilatum Uhler Figure 30 1857 Libellula assimilata Uhler, Acad. nat. sci. Phil. Proc. p. 88 1893 Diplax rubicundula var. assimilata Calvert, Am. ent. soc. Trans. 20 : 263 1899 Diplax rubicundula Kellicott, Odon. Ohio, p. 109 (description) This was very common at Saranac Inn in Little Clear creek. During the latter part of July the nymph could be seen any clear morning climbing up the Sparganium stems, and transforming. The nymphs were obtained whenever collecting was done from the beds of standing vegetation along the creek. Sympetrum rubicundulum Say Figure 30 1839 Libellula rubicundula Say, Acad. nat. sci. Phil. Jour. 8 : 26 1861 Diplax rubicundula Hagen, Synopsis Neur. N. Am. p. 176 1866 Diplax rubicundula Scudder, Bost. soc. nat. hist. Proc. 10:219 1893 Diplax rubicundula Calvert, Am. ent. soc. Trans. 20:262 (descrip- tion) 1899 Diplax rubicundula Kellicott, Odon. Ohio, p. 109 (description) 1900 Diplax rubicundula Williamson, Dragon flies Ind. p. 322 (descrip- tion) Pale, teneral, yellowish specimens of this species begin fluttering up out of the grasses that fill the shallow water in the upper reaches of most ponds about the latter end of June. A month later, when they have assumed their brillant black and red coloration, and have become more numerous, we find them scattered everywhere. They seem most numerous, however, about wet meadows, where they delight to go foraging. AQUATIC INSECTS IN THE ADIRONDACKS 525 The nymph, like that of the preceding and that of the following species (the only differences that I have observed between these I have already stated in a footnote to the nymph table) has nine lateral setae, and 12 mentals, of which the fifth (counting from the side) is longest; the dorsal hooks on segments 4-8 are low, less considerable in length than the segments which bear them, but sharp ; the lateral spines of the eighth and ninth segments are less developed, and follow in their external contour the incurvate lines of the posteriorly narrowing abdomen ; the lateral appendages are half as long as the inferiors, which are distinctly longer then the superior. Sympetrum obtrusum Hagen Figure 30 1867 Diplax obtrusa Hagen, Stett. ent. zeit. 28 : 95 1893 Diplax obtrusa Calvert, Am. ent. soc. Trans. 20:264 (description and figure) 1899 Diplax obtrusa Kellicott, Odon. Ohio, p. 109 (description and figure) 1900 Diplax obtrusa Williamson, Dragon flies Ind. p. 323 (description) For this and the two foregoing species I have hardly thought it worth while to state the distribution in detail, it is so general throughout the state, whenever any collecting has been done. Sympetrum albifrons Charpentier Figure 30 1841 Libellula albifrons Charpentier, Lib. Europ. p. 81, pi. 11, fig. 3 1861 Diplax albifrons Hagen, Synopsis Neur. N. Am. p. 177 1900 Sympetrum albifrons Williamson, Dragon flies Ind. p. 323 (descrip- tion) Not yet found in the state ; nymph unknown. Sympetrum corruptum Hagen 1861 Mesothemis corrupta Hagen, Synopsis Neur. N. Am. p. 171 1893 Diplax corrupta Calvert, Am. ent. soc. Trans. 20:264 (description) 1897 Diplax corrupta Calvert, N. Y. ent. soc. Jour. 5:95 (listed from Staten. Island) 1897 Diplax corrupta Van Duzee, N. Y. ent. soc. Jour. 5: 91 (listed from Lake Erie) 1899 Diplax corrupta Kellicott, Odon. Ohio, p. Ill (description) 1900 Diplax corrupta Williamson, Dragon flies Ind. p. 324 (description) This species is much more common westward; its nymph is unknown. 526 NEW YORK STATE MUSEUM PACHYDIPLAX There is a single species. Pachydiplax longipennis Burmeister 1839 Libellula longipennis Burmeister, Handb. ent. 2 : 850 1861 Mesothemis longipennis Hagen, Synopsis Neur. N. Am. p. 173 1893 P a c hydi plax longipennis Calvert, Am. ent. soc. Trans. 20 : 265 1895-97 Pachydiplax longipennis Calvert, N. Y. ent. soc. Jour. 3 : 48 and 5 : 94 (listed from New York, Westchester co., Ithaca and Black- rock) 1899 Pachydiplax longipennis Kellicott, Odon. Ohio, p. 114 (descrip- tion) 1900 Paehy d iplax longipennis Williamson, Dragon flies Ind. p. 326 (description) This is a species of very wide distribution. It has been recorded from most regions of North America, south of the Canadian, from Mexico, and from the Bahama islands, and last summer Dr O. S. West- cott, stopping to visit our station on his return from the Bermuda islands, brought a number of specimens collected in that new quarter. The species was not observed at large at Saranac Inn. It is likely to be found rather generally distributed throughout the state at lower alti- tudes. Imagos of this species are swift of wing, and somewhat difficult to capture with a net. The males hover near the surface of the water, darting hither and thither, meeting every newcomer, perching on a twig and immediately quitting it; and, when two males meet in combat, they have the curious habit of darting upward together into the air and flying skyward, often, till lost from view. The females are less in evidence. They rest habitually, except when foraging or ovipositing on trees back from the shore. When ovipositing over open water, they have a curious habit which I have not observed in other dragon flies : they do not rise and descend again between strokes of the end of the abdomen against the surface of the water, but fly along horizontally close to the surface and from time to time strike downward with the abdomen alone, pre- sumably washing off the eggs. In the midst of vegetation, however, they fly down and up again, as do other species. The nymphs clamber about among the trash, and, when grown, trans- form within a few inches of the margin of the water, if suitable place be found so near; otherwise they may go a distance of several feet. They are smooth, generally of dark color, with little pattern of color showing, except in the transverse banding of the femora. AQUATIC INSECTS IN THE ADIRONDACKS 527 Nymph. Total length 21 mm; abdomen 12 mm ; hind femur 6 mm ; width of head 6 mm, of abdomen 7.5 mm. Easily recognizable among other libelluline nymphs (when well grown at least) by the head twice as wide as long, the entire absence of dorsal hooks, the smooth and depressed body, and by the superior appendage being one third shorter than the inferiors and twice as long as the laterals. The labium is large, and the median lobe is at its maximum size; hook long and slender; laterals 10; mentals about 12, the fifth or sixth (counting from the side) longest; the lateral spines of the eighth and ninth segments of the abdomen are very similar in size and shape, those of the ninth segment extending posteriorly almost to the level of the tips of the inferior appendages. MESOTHEMIS There is a single species occurring within the state. Mesothemis simplicicollis Say 1839 Libel lula simpliGicollis Say, Acad. nat. sci. Phil. Jour. 8:28 1861 Me sot h em is simplicicollis Hagen, Synopsis Neur. N. Am. p. 170 1893 Mesothemis simplicicollis Calvert, Am. ent. soc. Trans. 20:265 (description) 1895-97 Mesothemis simplicicollis Calvert, N. Y. ent. soc. Jour. 3:48 and 5 : 94 (listed from New York, Westchester co., Ithaca and To- wanda creek) 1899 Mesothemis simplicicollis, Kellicott, Odon. Ohio, p. 113 (descrip- tion) 1900 Mesothemis simplicicollis, Williamson, Dragon flies Ind. p. 325 This is another species of wide distribution, that is much more common southward and westward : a single specimen was seen at Saranac Inn. I remember having seen but very few at Ithaca. I bred this species and P. longipennis in Illinois in 1895. The imagos of this species have more of the gomphine habit of squatting on the ground than any other libellulines known to me. That may be the meaning of the long spines on the hind femora. They do not seek the topmost twigs of reeds, as do most other shore-frequenting species, but settle by preference in some bare path, or aslant a board at the edge of the water. The nymphs are rapid climbers among reed stems. In life their eyes are yellowish exter- nally, and the teeth on the edges of the labial lobes are white. The bodies of the nymphs are greenish with little pattern showing. Nymph. Measures in total length 17 mm; abdomen 9 mm; hind femur 5 mm ; width of head 5 mm, of abdomen 5.5 mm. It is recognizable at a glance among all other libelluline nymphs known to me by the thickness of the body, the bulging prominence of the eyes, the relative brevity of the abdomen, and the decurved appendages at the apex of the abdomen. 528 NEW YORK STATE MUSEUM The median labial lobe is very prominent; the teeth on the edges of the lateral lobes are obsolete; the lateral setae are eight, and of these the proximal one is a small one; the mental setae are about 13, of which the eight outermost are a series of larger size. There are no dorsal hooks, but there are some coarse hairs on the transverse apical carinae of the segments, and there is a long brush of these springing from the apical ventral margin of the ninth segment; there are no lateral spines, or the merest vestiges of them remain sometimes on the ninth segment: the appendages are all decurved, the inferiors most strongly ; the superior is a little shorter than the inferiors, a little longer than the laterals; the prothoracic spiracles are elevated to the highest point of the body. So unique are a number of these characters, there is no confusing this nymph with the others of the subfamily. MICRATHYRIA A single species of our fauna is referred to this genus. Micrathyria berenice Drury 1773 Lib e 11 ul a berenice Drury, Illus. exotic en t. v. 1, pi. 48, fig. 3 1839 Lib ell ul a berenice Say, Acad. nat. sci. PhiL Jour. 8:25 1861 Di pi ax berenice Hagen, Syuopsis Neur. N. Am. p. 178 1867 Diplax berenice Packard, Am. nat. 1 : 311, pi. 9, fig. 3 and 4 1893 Micrathyria berenice Calvert, Am. ent. see. Traus. 20 : 260 (de- scription) 1895-97 Micrathyria berenice Calvert, N. Y. ent. soc. Jour. 3:47 and 5 ; 94 (listed from Thousand Islands, New York and Sheepshead bay, L. L) This is a species I have never seen alive. It is said to be common down the valley of the Hudson. Its nymph is unknown. LADONA Of the three forms comprising this genus, originally described as distinct species, two probably occur within the limits of New York state. In what I have written concerning these hitherto, I have followed with- out question the synonymy as given by Hagen and Calvert, according to which both deplanata of Rambur and j u 1 i a of Uhler are but varieties of e x u s t a Say, not even bearing a varietal name. A. P. Morse has called my attention to some facts which seem to indicate that these three may yet have to be considered as distinct species. I may add that my breedings have furnished farther facts corroborating this opinion. Before the " lumpmg " process began the bibliography of these forms was as follows. 1839 Libellula exusta Say, Acad. nat. sci. Phil. Jour. 8 : 29 1842 Libellula deplanata Eambur, Ins. Neur. p. 75 1857 Libellula julia Uhler, Acad. nat. sci. Phil. Proc. p. 88 AQUATIC INSECTS IN THE ADIRONDACKS 529 Then Hagen, in his Synopsis of the Neuroptera of North America (186 1), ranked deplanata and exusta as synonymous (under the later name, however) ; in his Synopsis of the Odoiiata of America (1875) he ranked them separately, remarking that deplanata was probably but a dwarf southern form of exusta, but he wrote down j u 1 i a as a synonym of exusta. In 1893 Calvert in his Odonata of Philadelphia and vicinity again added deplanata to the exusta lump. The three have been treated as one ever since, and in all recent descriptions and lists, dimensions, coloration, structural characters and distribution are hopelessly confused; and it becomes necessary to revert to the original descriptions to find statement of differences between them. The two which concern us here in New York are L. e x u s t a Say and L. Julia Uhler. So far as I am able to judge by my own specimens and by those in the Museum of comparative zoology at Cambridge, these seem to be distinguished by the following characters. a Dorsum of the thorax pale with a black stripe each side on the humeral suture, no ante-humeral stripe of white; the fuscous spot on the base of the hind wing not enveloping the triangle ; the eii^hth abdominal segment of the male narrower than the seventh ; the apex of the anterior branch of the genital hamule of the male directed laterally julia aa Dorsum of the thorax blackish brown, with a white ante-humeral stripe each side; the fuscous spot of the hind wing envelops the triangle ; the eighth abdominal segment in the male is as wide as or wider than the seventh; the apex of the anterior branch of the genital hamule of the male is directed posteriorly „ exusta I have described in the Canadian eiiiomologist for 1897 (29:144-46) the nymphs of deplanata from Florida. These differ from the nymphs of L. j uli a described below by some unusu- ally good specific characters, such as the entire absence of raptorial setae from the median lobe of the labium, and the hooked teeth on the margin of the lateral lobes. It remains now to discover the nymph of exusta, and ^ \j^ to learn whether deplanata agrees with it. (^[j / It will be observed that the characters given in the W.^-^ t) ( generic table for nymphs at the beginning of this sub- ^.^ 3^ ^^,^ ^^^^^^ family abundantly justify the erection of Ladona as T^il%^t iu)^t^al r T •! -11 1 exusta Say (1)1 a genus separate from Libellula. L. e X u s t a is recorded in Calvert's list of the Odonata of New York state from Lake George, and Croton on Hudson. Whether the record be for exusta or for julia, is uncertain. The characters given above will I trust, enable the collector in the future to distinguish between these 530 NEW YORK STATE MUSEUM two ; and if some collector find the typical e x u s t a to be common, he may aid the farther solution of this question by setting about to find its nymph. I discuss below the single form which I have found within the state. Ladona julia Uhler 1857 Libellula julia Uhler, Acad. nat. sci. Phil. Proc. p. 88 1861 Libellula Julia Hagen, Synopsis Neur. N. Am. p. 153 1867 Libellula julia Hageu, Stett. ent. zeit. 28 : 192 This species was very common at Saranac Inn. It was beginning to appear in numbers on the wing at the time of our arrival, June 13. I went out to the banks of Little Clear pond at sunrise of the morning of the 14th and found a number of nymphs transforming, associated with Tetragoneuria. The imagos were abundant along every roadside during the month of June, and females were only a little less in evidence than the males. Nymphs were taken abundantly from the trashy places in the borders of Little Clear and Bone ponds, and a few were found in Little Clear creek; exuviae were seen in numbers clinging to the banks of Colby pond, and a few along Stony brook near Axton. Nymph. Total length 24 mm; abdomen 15.5 mm; hind femur 5.5 mm; width of head 5 mm, of abdomen 5.5 mm. Body slender, elongate, moderately hairy, dark colored, without distinct pattern, but paler on the sutures and below. Head somewhat wider than long, with eyes not very prominent, and hind margin slightly concave; median lobe of the labium with a median flat, toothlike prominence in the middle of its free border, on either side of which the border is crenulate, with spinules inserted singly in the notches between the crenulations; lateral setae six; hook slender, and not very long; mental setae three each side. Abdomen with sharp lateral spines, relatively shorter than on the nymph of deplanata; dorsal hooks on segments 4-8 straight and. sharp ; superior and inferior appendages of about equal length, and about as long as the last two abdominal segments; lateral appendages one fifth to one fourth as long as the others. The presence of three mental setae on the labium will distinguish this species at a glance from the nymph ofL. deplanata of the south. LIBELLULA This genus contains the species which are, perhaps, the best known of all our dragon flies. The imagos hover habitually over ponds in summer, are large, and for the most part beautifully colored, and are everywhere common. Eight species are known from the state, and it is not likely that any others will be found resident in numbers. It is of course always possible for a few strays to be blown into new territory from distant regions by high winds. The nymphs of five of these eight species are AQUATIC INSECTS IN THE ADIRONDACKS 53I known, and are described and distinguished below. So much alike are they that a general account of the nymphal characters will save much restatement. The known nymphs of this genus agree in having the body elongate, tapering to the pointed apex of the abdomen, hairy, the hairs serving to hold an ambuscade of silt about the body. Head compact, little wider than long, with the eyes capping the anterolateral angles, and directed ante- riorly; head little narrowed behind the eyes; labium large, reaching posteriorly between the bases of the middle legs ; median lobe with its front border not crenate ; mental setae always present, variable in number; lateral setae five to nine; prothorax with a flatish dorsal shield, whose margins are generally fringed with coarse hairs ; wing cases reach- ing the base of the sixth abdominal segment; abdomen triquetral, its lateral margins becoming acute posteriorly, with short lateral spines on segments 8 and 9 ; a variable number of dorsal hooks beginning on the third or fourth segment, sometimes quite rudimentary ; ninth segment two to three times as long as the loth ; lateral appendages half as long as the others; tarsi with the second and third joints successively each a very little longer than the first. The imagos discussed below, and the known nymphs of the same species may be separated by the following keys. KEY TO SPECIES OF LIBELLULA Imagos a Wings with no spot at the nodus b With a broad basal band of black covering the basal third of both wings b as al is hb With the black color of the base of the wings confined to a narrow streak in the subcostal space, or entirely wanting c Stigma bicolored d Inner half of stigma white or yellow, outer half dark brown, c y a n e a dd Stigma mainly yellow, but distinctly darker at the outer end plumbea cc Stigma not differing in color at its inner and outer ends d Stigma red or yellow; wings flavescent, unspotted auripennis dd Stigma black incesta aa Wings with a small nodal spot which is restricted to the outer (distal) side of the nodus 6 With a large triangular patch of black extending from the triangle to the hind margin qxia d ri m ac u 1 a t a ih Without a black patch between the triangle and the huid margin in the hind wing vibrans aaa With a large nodal spot which completely surrounds the nodus i Nodal and apical wing spots yellowish or reddish semifasciata lb Nodal and apical wing spots blackish pulchella 532 NEW YORK STATE MUSEUM Nymphs a Dorsal hooks on the seventh and eighth abdominal segments long and sharp h Lateral setae five auripennis ih Lateral setae six cyanea ihi Lateral setae seven has alia aa Dorsal hooks on the seventh and eighth abdominal segments rudimentary (and hidden among scurfy hairs) or wanting b Lateral setae seven quadrimaculata hh Lateral setae eight to nine pulchella aaa Nymphs unknown axillena, plumbea, incesta and semifasciata Libellula basalis Say 1839 Lib ell ul a basalis Say, Acad. nat. sci. Phil. Jour. 8:23 1839 Libellula luctuosa Burmeister, Handb. ent. 2:861 1861 Libellula luctuosa Hagen, Synopsis Neur. N. Am. p. 152 1875 Libellula basalis Hagen, Bost. soc. nat. hist. Proc. 18: 70 1893 Libellul a basalis Calvert, Am. ent. soc. Trans. 20:255 (description) 1895-97 Libellula basalis Calvert, N. Y. ent. soc. Jour. 3:47 and 5:94 (listed from Dobbs Ferry, Ithaca, Kenwood, Niagara river) 1899 Libellula basalis Kellicott, Odon. Ohio, p. 96 (description) 1900 Libellula basalis Williamson, Dragon flies Ind. p. 329 This is not one of the more common species apparently in New York state. I have taken a few specimens at Ithaca ; I saw one imago at Saranac Inn, and took one nymph there. I studied and reared the species in 1895 at Galesburg 111., where it is abundant. Of a June morning half an hour after sunrise, I have seen scores of the nymphs transforming at a time on the blue-grass bordered banks of a little pond. Nymph. Total length 25 mm; abdomen, 14 mm; hind femur 5.5 mm; width of head, 5.5 mm, of abdomen, 6.5 mm. The points which will chiefly serve for comparison with other species are as follows : body not very hairy, generally dirty and showing little color pattern; lateral setae, seven; mental setae about 10 or 11, the outer five or six in a longer series ; movable hook, long, slender, little curved; dorsal hooks on abdominal segments 4-8 all sharp and well exposed, but the sixth longest. Libellula auripennis Burmeister Golden-wing 1839 Libellula auripennis Burmeister, Handb. ent. 2 : 861 1861 Li bell u la auripeunis Hagen, Synopsis Neur. N. Am. p. 155 1866 Libellula auripennis Scudder, Bost. soc. nat. liist. Proc. 10:191 1893 Libellula auripennis Calvert, Am. ent. soc. Trans. 20:256 (de- scription) AQUATIC INSECTS IN THE ADIRONDACKS 533 1895 Libellula auripennis N. Y. ent. soc. Jour. 3:47 (listed from the vicinity of New York) 1899 Libellula auripennis Kellicott, Odori. Ohio, p. 97 ^description) 1900 Libellula auripennis Williamson, Dragon flies Ind. p. 329 (de- scription) This beautiful, golden-winged, southern species is not likely to be found in the state except near the coast. . A few years ago Prof. A. L. Quaint- ance reared the species at Lake City Fla., and very kindly sent me the bred specimen with its cast skin, and some nymphs in alcohol. I have several times since received the nymphs from other localities in the south. I have not seen the species at large. Nymph. Total length 27 mm; abdomen 17.3 mm; hind femur 6 mm; width of head 6 mm, of abdomen 7 mm. The body is a trifle heavier than in the nymph of b a s a 1 i s and more hairy; the median lobe of the labium is decidedly pointed in the middle of its front border; lateral setae five; mental setae eight to ten, the six outer ones forming a larger series; movable hook rather stout and little curved ; ninth abdominal segment twice as long on the ventral as on the dorsal side, twice as long above as the loth segment; dorsal hooks on segments 3 or 4-8, straight, and sharp; appendages as long as the two last abdominal segments, the laterals half as long as the others. Libellula vibrans Fabricius 1793 Libellula vibrans Fabricius, Ent. syst. 2 : 380 1861 Libellula 1yd ia Hagen, Synopsis Neur. N. Am. p. 155 1893 Libellula axillena vibran s Calvert, Am. ent. soc. Trans. 20: 257 1895 Libellula axillena vibrans Calvert, N. Y. ent. soc. Jour. 3:47 (listed from Staten Island and Westchester co.) 1899 Libellula vibrans Kellicott, Odon.Ohio, p. 98 (description) 1900 Libellula vibrans Williamson, Dragon flies Ind. p. 330 (description) Another handsome, graceful, well proportioned insect, of very swift flight; apparently not common in this state. Its nymph is unknown, Libellula incesta Hagen 1861 Libellula incesta Hagen, Synopsis Neur. N.Am. p. 155 1893 Libellula axillena incesta Calvert, Am. ent. soc. Trans. 20 : 257 1899 Libellula incesta Kellicott, Odon. Ohio, p. 99 (description ) 1900 Libellula incesta Williamson, Dragon flies Ind. p, 330 This species has not as yet been taken in the state : it is almost sure to be found there eventually. It ranges from New Hampshire to Texas, and is said to be common in places in Ohio. Its nymph is unknown. 534 NEW YORK STATE MUSEUM Libellula plumbea Uhler 1857 Libellula plumbea Uhler, Acad. uat. sci. Phil. Proc. p. 87 1861 Libellula plumbea Hagen, Synopsis Neur. N. Am. p. 157 1893 Libellula plumbea Calvert, Am. ent. soc. Trans. 20 : 256 (description) 1895 Libellula plumbea Calvert, N. Y. ent. soc. Jour. 3 ; 47 (listed from Westchester co.) This is another southern species which seems not likely to be found commonly in the state excepting possibly in the lower valley of the Hudson river. Its nymph is unknown, Libellula cyanea Fabricius 1775 Libellula cyanea Fabricius, Syst. ent, p. 424 1839 Libellula quadrupla Say, Acad, nat, sci, Phil, Jour. 8 ; 23 1857 Libellula bistigma Uhler, Acad. nat. sci. Phil. Proc, p. 87 1861 Libellula quadrupla Hagen, Synopsis Neur, N, Am. p. 1.57 1893 Libellula cyanea Calvert, Am, ent. soc. Trans, 20:556 (description) 1895 Libellula cyanea Calvert, N, Y. ent, soc. Jour. 3:47 (listed from the vicinity of New York) 1899 Libellula cyanea Kellicott, Odon. Ohio, p. 97 (descrijition) 1900 Libellula cyanea Williamson, Dragon flies lud. p. 330. This species ranges from Massachusetts to Indiana and South Carolina ; it is likely to be found eventually in numerous unreported localities in New York state, I have not seen it at large, but I have been allowed to study a bred specimen kindly lent me by Samuel Henshaw, and from that specimen, the following characters of the nymph are drawn. Nymph. Total length 20 mm; abdomen 13.5 mm; hind femur 5 mm; width of head 5 mm, of abdomen 6.5 mm. The head is considerably narrowed behind the eyes, and the hind angles are rough hairy; lateral setae six; mental setae eight or nine, the six or seven external ones forming a stronger series ; the movable hook is stout, short and almost straight ; dorsal hooks on abdominal seg- ments 4-8, straight and sharp ; lateral spines spinulose hairy externally, those of the ninth segment shorter than the loth segment, 9th segment a little more than twice as long as the loth ; appendages as long as the last two segments, the lateral appendages half as long as the others. Libellula quadrimaculata Linnaeus 1785 Libellula quadrimaculata Linnaeus, Syst. nat. 1 : 543 1861 Libellula quadrimaculata Hagen, Synopsis Neur. N. Am. p. 150 1867 Libellula quadrimaculata Packard, Am. nat. 1 : 310, pi. 9, fig. 2 1893 Libel lu la quadrimaculata Calvert, Am. ent. soc. Trans. 20:258 1893-97 Libellula quadrimaculata Calvert, N. Y. ent. soc. Jour, 3 : 47 and 5 : 94 (listed from New York, Ithaca, Schoharie, Karner and Buffalo) 1899 Libellula quadrimaculata Kellicott, Odon, Ohio, p. 100 (descrip- tion) 1900 Libellula quadrimaculata Williamson, Dragon flies lud, p, 331 (description) , AQUATIC INSECTS IN THE ADIRONDACKS 535 This species occurred sparingly at Saranac Inn. A few images were seen sitting on twigs which rose directly a few feet out of the water. They were shy and difficult to capture, and, when disturbed, would rarely return to the same vicinity. I have not been able to find this so common species in its immature stages in person, but I have nymphs sent me from EUenville N. Y, by Chester Young, and others from the state of Wash- ington; these agree well with specimens from France which I have received from my esteemed correspondent, M. Rene Martin, of Leblanc. The nymph of this species has long been known in Europe. Nymph. The largest EUenville nymph, apparently full grown, meas- ures in total length 26 mm; abdomen 18 mm ; hind femur 6 mm ; width of head 6 mm, of abdomen 8 mm. The head is very compact in this nymph, scarcely narrowed behind the eyes ; the median lobe of the labium is produced at the middle of its free border into a flat, toothlike prominence ; lateral setae seven ; mental setae about 13, of which the seven outermost are longest; movable hook slender and incurvate ; the dorsum of the body is scurfy hairy (hardly less so than in L. p u 1 c h e 1 1 a , described below), and the hairs partly obscure the dorsal hooks which are present on segments 3-8 of abdomen, that of the eighth segment short and rudimentary ; lateral spines very short; segment 10 about half as long on the dorsal as on the ventral side ; appendages fully as long as the last two abdominal segments. The laterals have unusual length for a member of this genus in being but about one fourth shorter than the others. Libellula semifasciata Burmeister Plate 23, fig. 1 1839 L ib ellula semifasciata Burmeister, Handb. eut. 2 ; 862 1861 Libellula semifasciata Hagen, Synopsis Neur. N. Am. p. 151 1839 Libellula ternaria Say, Acad. nat. sci. Phil. Jour. 8: 21 1842 Libellula maculata Rambur, Ins. Neur. p. 55 1893 Libellula semifasciata Calvert, Am. ent. soc. Trans. 20 : 258 1895-97 Libellula semifasciata Calvert, N. Y. ent. soc. Jour. 3 : 47 and 5 : 94 (listed from New York, Dobbs Ferry and Buffalo) 1898 Lib ellula semifasciata Needham, Outdoor studies, p. 55, fig. 54 1899 Libellula semifasciata Kellicott, Odon. Ohio, p. 100 (description) 1900 Libellula semifasciata Williamson, Dragon flies Ind. p. 332 (de- scription) In the north this species is the earliest of the genus to be abroad in the spring, making its appearance before the middle of May. I have oftenest found the imago about woodland brooks — rarely about ponds. I have never found the nymph ; it is still unknown. 53^ NEW YORK STATE MUSEUM Libellula pulchella Drury Plate 23, fig. 3 1773 Libellula pulchella Drury, Illus. exotic eot. v. 1, pi. 48, fig. 5 1857 Libellula confusa Uhler, Acad. uat. sci. Phil. Proc. p. 87 1861 Lib el lu la pulchella Hagen, Synopsis Neur. N. Am. p. 153 1893 L i bel 1 ula pulchella Calvert, Am. ent. soc. Trans. 20:259 1895-97 Libellula pulchella Calvert, N. Y. ent. soc. Jour. 3:47 and 5 : 94 (listed from Keesevllle, Dobbs Ferry, New York, Ithaca, Scho- harie and Buffalo) 1898 Libellula pulchella Needham, Outdoor studies, p. 56, fig. 55 1899 Libellula pulchella Kellicott, Odon. Ohio, p. 101 (description) 1900 Libellula pulchella Williamson, Dragon flies Ind. p. 332 (descrip- tion) This beautiful, pond-loving species is one of the best known of all Odonata peculiar to North America. The old and white pruinose males hovering over the open water under the summer sun are certainly suffi- ciently striking to catch the eye of the most casual observer. The species was not common at Saranac Inn. But a few specimens were seen there. I reared one specimen there, many at Ithaca (where the species is abundant) and many in Illinois. Nymph. Total length 26 mm; abdomen 16 mm; hind femur 6 mm; width of head 6 mm, of abdomen 8 mm. All the ridges on the dorsum of this nymph are fringed with stiff, strong, erect hairs ; these are specially marked about the borders of the prothbracic shield, and on the rear of the head; the labium is rather regularly rounded on the prominent median lobe, lacking the median toothlike prominence of some of the other species; the lateral setae are eight to nine ; mental setae 12-13, the seven outermost each side longest; the lateral spines are moderate ; the dorsal hooks are quite distinctive, being represented only on segments 4-6, rudimentary, or sometimes wanting altogether. Among my Ithaca nymphs were a good many on which I could find no dorsal hooks at all. My Illinois specimens agree with the nymph from Peoria 111., figured by Cabot, ^ and referred by doubtful supposition to Neurocordulia obsoleta. PLATHEMIS There is a single species within our limits. Plathemis lydia Drury Plate 21, flg. : 1770 Libellula lydia Drury, Illus. exotic ent. 1 : 112, pi. 47, fig. 4 1773 Lib ell ula trimaculata DeGeer, Mem. ins. 3 : 556, pi. 26, fig. 2 1854 Emmons, Agric. N. Y. v. 5, pi. 15, fig. 4 and 5 (no name or description) 1 Immature state of the Odonata. pt 3, pi. 6, fig. 6. AQUATIC INSECTS IN THE ADIRONDACKS 537 1867 Libellula trimaculata Packard, Am. nat. 1 ; 310, pi. 9, fig. 1 1861 Pla the mis trimaculata Hagen, Synopsis Neur. N. Am. p. 149 1873 Libellula trimaculata Eiley, Ins. Mo. 5tb rep't, p. 14 (This article contains a woodcut of this species which has been most extensively copied in this country.) 1893 Plathemis trimaculata Calvert, Am. ent. soc. Trans. 20 : 259 1895-97 Plathemis trimaculata Calvert, N. Y. ent. soc. Jour. 3 ; 47 and 5 : 94 (listed from New York, Dobbs Ferry, Itbaca, Sctioharie, Albany and Buffalo) 1898 L i b ell ul a trimaculata Needham, Outdoor studies, p. 57 and 65, fig. 56 and 66 1899 Plathemis trimaculata Kellicott, Odou. Ohio, p. 102 (description) 1900 Plathemis lydia Williamson, Dragon flies Ind. p. 333 (descriijtion) This is another well known, widely distributed and generally common species^ which inhabits ponds and ditches generally. I present herewith (fig. 32) a figure of its nymph, which I have pre- viously published in Outdoor studies. It differs firom Libellula and L a d o n a in having the head widest behind the eyes, and firom Libellula in having the front margin of the median lobe of the labium crenulate. Nymph. Total length 24 mm ; abdomen 14 mm ; hind femur 4.5 mm; width of head 4.5 mm, of abdo- men 5.5 mm. Body elongate, rather smooth, and more free from dirt than most Libellulas, generally showing two bands of blackish brown extending from beneath the tips of the wing cases to the bases of the lateral ap- pendages. Head not widened behind the eyes, but •.| .J 111 I'll rli- ■ -TIJ,. a