m ; • HARVARD UNIVERSITY LIBRARY OF THE Museum of Comparative Zoology THE -^if^ KANSAS UNIVERSITY SCIENCE BULLETIN DEVOTED TO THE PUBLICATION OF THE RESULTS OF RESEARCH BY MEMBERS OF THE UNTVERSITY OF KANSAS VOL. XI PUBLISHED BY THE UNIVERSITY Lawrence, Kan. \ [ {\ w ^^ ^^ -iv '}'{) rr n-3273 - /^n CONTENTS OF VOLUME XI. No. 1. — The Biology and Ecology of Aquatic and Semiaquatic Hemiptera. Plates I "to XXX. By H. B. Hunger ford 3 Xo. 2. — The Male Genitalia as Characters of Specific Value in Certain Cryptocerata (Hemiptera-Heteroptera). Plates XXXI to XXXII. By H.B. Hunger jord 329 i BULLETIN OF THE UNIVERSITY OF KANSAS ' Vol. XXI. DECEMBER 1, 1919. No. 17. Science Bulletin Vol. XL (Continuation of Kansas University Quarterly.) LAWRENCE, KANSAS Published Semimonthly from January to June and Monthly from July to December, inclusive, by the University of Kansas. m I K ered as second-class matter December 29, 1910, at tJie post office at Lawrence. Kansas, ! under the act of ,iuly 16, 1394. 31669 NOTICE TO EXCHANGES. , The- at^tention of learned societies and other institutions which e'xchahg-e scientific publications with the University of Kansas is called to the list of publications of this University on the third and fourth pages of the cover of this issue. Those marked "Supply exhausted" cannot be furnished at all; those marked "Supply small" cannot be furnished sep- arately; those marked "Supply large" will gladly be furnished to any of our exchanges who may need them to complete their files. Back numbers of the Kansas University Quarterly and Geo- logical Survey, as far as possible, will be sent to those of our newer correspondents who are able and willing to reciprocate. ANNOUNCEMENT. The Kansas University Science Bulletiyi (continuation of the Kansas University Quarterly) is Issued in parts at irregu- lar intervals. One or more volumes, containing from 300 to 400 pages of reading-matter, with necessary illustrations, is issued each year. The subscription price is $3 per volume. Exchanges with other institutions and learned societies every- where are solicited. All exchanges should be addressed to the Library of the University of Kansas. All communications should be addressed to The Kansas University Science Bulletin, lawrence, kan. EDITORIAL BOARD. W. J. BAUMGARTNER, Managing Editor. ■ H. E. JORDAN, Exchange Editor. S. J. HUNTER. W. C. STEVENS. W. S. HUNTER. O. O. STOLAND. world by sity of V COLOR PLATE I. Fig. 1. Filaments of Spirogyra before being fed upon by a Corixid. Fig. 2. The same after being fed upon by the bug. Note tho empty filaments. Fig. 3. An adult Corixid. (Water boatman.) Fig. 4. A highly magnified portion of the Spirogyra shown in figure 2. Note the punctured and empty cells. Fig. 5. The stomach contents of a small Corixid nymph after thirty minutes feeding on Spirogyra. The above illustrations form conclusive proof of the herbivorous tastes of the water boatmen, and modify the frequent assertions of textbooks and serials that "All aquatic Hemiptera are predaceous." The colored drawings on these three plates were made by Miss Ellen Edmonson. — 1669 1 OR PI ATF •?-/'•- ^->'. li *£. A Ni \ ^^1 p., ■> •'Slit^V- / N EDMONSON DEL. AD NAT. COLOR PLATE H. Fig. 1. Notonecta undulata Say. Our most common Kansas back swimmer. Magnification, 3% times. Fig. 2. Plea striola Fieb. The tiniest of the back swimmers and the pigmy of the water bugs. Magnification, 3.9 times. Fig. 3. Ranatra or water scorpion. Lives in the trash of the pool and feeds upon luckless insects and even small fish. (This specimen iden- tified in our Snow collections as Ranatra americana.) .7 natural size. Fig. 4." Bnenoa margaretacea Bueno. A slender back swimmer whose main food supply consists of the little Entomostraca crustacean creatures which form the food supply of practically all young fish. A form harmful to fish culture for this reason. Magnification, SV2 times. Fig. 5. Benacus griseus Say. The large "electric-light bug" or "giant water bug." Destructive to fish up to three inches long at least. .7 natural size. Fig. 6. Abedus sp? Male carrying the eggs which the female has glued to his back for safe keeping. .7 natural size. Fig. 7. Nepa apicnlata Uhl. A bug belonging to the same family as Ranatra, the Nepidse. Found in mud and debris of shallow water. Mag- nification, 1% times. Fig. 8. Pelocoris carolinensis Bueno. A "ci-eeping water bug" which lives in the tangled vegetation of fresh pools. Predatory in habits. One of the quickest of the water bugs to "sting" a careless collector. (Family Naucoridse.) Magnification, 2.2 times. Fig. 9. Belostoma fliimine an'^a.y. A bug common in Kansas ponds. Feeds upon small water animals, including fish. The male with his back burdened with eggs is to be taken almost any time during summer. Mag- nification, 1% times. H COLOR PLATT II COLOR PLATE IIL SEMIAQUATICS. Fig. 1. Hebr-us concinnus Uhl. A tiny bug dwelling on the shore and plant rafts. (Family Hebridae.) Magnification, 121717 times. Fig. 2. Hydrometra martini Kirk. An exceedingly slender little bug living upon plant rafts. Called a "marsh treader." (Family Hydro- metridse, formerly Limnobatidae.) Magnification, ZYz times. Fig. 3. Rhagovelia obesa Uhl. A dweller upon the fast running wa- ters. (Family Veliidse.) Magnification, 7%5 times. Fig. 4. Trepobates pictus H. S. A beautiful surface strider. (Family Gerridae.) Magnification, 7%5 times. Fig. 5. Gerris marginatus Say. Our common water strider. Mag- nification, 3y2 times. Fig. 6. Mesovelia mulsanti White. A small bug about the size of a chinch bug living in the same haunts as Hydrometra. (Family Meso- veliidae.) Magnification, 7%5 times. Fig. 7. Microvelia borealis Bueno. A tiny little bug found upon the water and about the banks of pools. This specimen is wingless, but many are winged. Magnification, 121717 times. Fig. 8. Gelastocoris, species new? The toad bug at home on the sandy shores of our streams (whether this bug is G. oculatus, variegatus or another is still in doubt. Some will say it is variegatus, being too well marked for oculatus.) Magnification, 3%- times. Fig. 9. Ochterus americarmi\51n\. A shore bug intermediate between the toad bug and the Saldid shown in figure 10. The antennae are inter- mediate in length between the long antennae of the Soldidae and the short antennse of the toad bug. True aquatics have hidden antennas. The toad bug has no objection to a swim in the water. The series from semi- aquatic to true aquatic is shown by a study of figures 10, 9 and 8 of this plate and figure 8 of color plate IL Magnification, 6%7 times. Fig. 10. Pentacora signoreti Guer. (Specimen determined in Snow collections.) Magnification, 6%7 times. COl.DR PI ATF III THE KANSAS UNIVERSITY SCIENCE BULLETIN Vol. XI— DECEMBER, 1919. ("V^Tiole Series, Vol. XXI, No. 17.) ENTOMOLOGY NUMBER. CONTENTS: The Biology and Ecx)logy of Aquatic and Semiaquatic Hemiptera, H. B. Hungerford. The Male Genitalia as Characters of Specific Value in Certain Cryptocerata (Hemiptera-Heteroptera), H. B. Hungerford. PUBLISHED BY THE UNIVERSITY LAWRENCE, KAN. Entered at the post office in Lawrence as second-class matter. 8-1669 KANSAS STATE PRINTING PLANT 1MRI ZXJMWALT, Statk Pri?.-ter TOPEKA. 19 20 81669 THE KANSAS UNIVERSITY SCIENCE BULLETIN Vol. XL] December, 1919. [ voT.Tx^?"NTl7 The Biology and Ecology of Aquatic and Semiaquatic Hemiptera* BY H. B. HUNGERFORD. Department of Entomology, University of Kansas. ACKNOWLEDGMENTS. The writer wishes to acknowledge herewith his indebted- ness to those who have aided him in his work. First, to Dr. James G. Needham, of Cornell University, under whose direction these studies were made, he feels the deepest obligation and gratitude for the incentive and oppor- tunity to investigate this neglected ecological group. His helpful, kindly suggestions and his broad limnological exper- ience have ever been a source of inspiration to the writer in the preparation of this thesis. To Prof. S. J. Hunter, of Kansas University, for so gener- ously placing at his disposal time and equipment sufficient to complete these studies. To Miss Ellen Edmonson, of Kansas University, to whose patient and painstaking care is due the accuracy and sightli- ness of many of the illustrations. To Mr. J. R. de La Torre Bueno, who has lor.ned and identi- fied material so generously and whose writings upon special studies have been exceedingly helpful. To Mr. Edmund H. Gibson, of Washington, D. C, who has extended, whole heartedly, the facilities at his command. To Mr. E. P. Van Duzee, for bringing out a catalog of the * Submitted to the Department of Entomology and the graduate faculty of Cornel! TTniversitv in partial fulfillment of the requirements for the degree of Doctor of Philosophy, July. 1918. Received for publication November 15, 1919. (3) 4 THE UNIVERSITY SCIENCE BULLETIN. Hemiptera which has facilitated greatly the preparation of this work. To Dr. P. W. Claassen and Mr. Clyde Hamilton, of Cornell University, and to Miss Ruby Hosford, Dr. C. P. Alexander, Dr. Paul B. Lawson, Mr. Raymond Beamer and Miss Ger- trude Standing, of Kansas University, for special assistance from time to time, and to many others, who, one way or an- other, have contributed to the completeness of this work, he is most duly grateful. TABLE OF CONTENTS. PAGE Acknowledgments 3 Foreword 7 Introduction 8 Survey of Families Including a Synoptic Key to Aquatic and Semiaquatic Hemiptera, (Key p. 11) 9 Historical Sketch of the Biology of Aquatic and Semiaquatic Hemiptera 13 Ecologic and Economic Relations, Including a Habitat Key to THE Aquatic and Semiaquatic Heteroptera. (Key p. 29), 17 Form and Function 38 Semiaquatics: Gelastocoridse — Taxonomy of Family 45 Biology of Family 49 Ochteridse — Taxonomy of Family 51 Biology of Family 53 Saldidse — Taxonomy of Family 54 Biology of Family 79 Hehridse — Taxonomy of Family 82 Biology of Family 88 Hydrometridx — Taxonomy of Family 91 Biology of Family 92 Mesoveliidse — Taxonomy of Family 99 Biology of Family 101 Gerridse — Taxonomy of Family 106 Biology of Family - 116 Veliidse — Taxonomy of Family 121 Biology of Family 134 Aquatics: Belostomatidse — Taxonomy of Family 141 Biology of Family 142 (5) 6 TABLE OF CONTENTS. Aquatics — Concluded. Nepidse — PAGE Taxonomy of Family 151 Biology of Family 157 Notonectidse — Taxonomy of Family 164 Biology of Family 177 Naucoridse — Taxonomy of Family 198 Biology of Family 207 Corixidse — Taxonomy of Family 210 Biology of Family 215 (Food of Corixids) 234 General Review 250 Bibliography 251 Plates 266 The Male Genitalia as Characters of Specific Value in Certain Cryptocerata (Hemiptera-Heteroptera) 329 FOREWORD. It has been the aim of the writer to gather together, within the covers of one volume, the gist of all the information now available concerning the biology of the aquatic Hemiptera. There was no intention in the beginning to include descrip- tions of species or other taxonomic matter. It was found, however, that there exists no work containing the descriptions of American genera and species.* These have been gathered together from various sources, some of them well nigh inac- cessible, and are included in this paper to facilitate further study in the group. The writer does not pretend to be an authority on systematic literature. He has followed Van Duzee's checklist and cata- logue faithfully, digressing only in those cases where he has had the advice from taxonomists in the various families. Keys have been improvised from the literature, reduced to a synop- tic plan, and tested upon all available material. This phase of the work, however, has been secondary and incidental to the main problem of extending the range of our knowledge of the ecology and biology of the water bugs. To this end the writer has searched the early literature for the first biological notes applied to the water bugs, has gleaned the periodicals, other serials and texts, and arranged the results in this paper under the families and genera as they now stand, adding his own contributions on the behavior, life history and ecological relations of these most interesting insects. * Generic descriptions are often brief notes and specific descriptions are omitted for Belostomatidse and Corixidfe, groups now undergoing careful revision. (7) INTRODUCTION. In the summer of 1910 the writer was a member of a party which made an entomological survey of some fifteen counties in northwestern Kansas. The field work was under the immediate direction of F. X. Williams, while the collecting and listing of the Heteroptera was assigned to the writer. It was in this work that his interest was aroused in this group. Thus, when the opportunity came to work upon some limno- logical problem, under the direction of Dr. James G. Needham, it was very happily arranged that a study of the biology and ecology of the aquatic Hemiptera should be undertaken. There are some thirteen families of Heteroptera that main- tain a more or less intimate connection with the water. The Saldidae, Gelastocoridse, Ochteridse and Hebridse live upon the shore. The Hydrometridse, Mesoveliidse, and some of the Veliidse (Microvelia, for instance) extend their range to the floating mats of green algae and other plant rafts. The Gerridae and some Veliidse course the surface of the waters. While within the water dwell the Nepidse and Belostomatidae, which keep a more or less constant contact with the surface, and the Naucoridae, Notonectidae and Corixidae that dart here and there through the water at will. Bound together by the ecological factor of environment and relationship within an order, it has been the endeavor to treat, 'n the following pages, the habits, life histories, interrelations and outside associations of the water bugs in such a way that the result may be a finished thesis rather than a heterogeneous collection of notes. This is a difficult task from the very nature of the material treated. A glance at the table of con- tents will indicate the general arrangement of subject matter. (8) Survey of Families, Including a Synoptic Key to the Aquatic and Semiaquatic Hemiptera. The water bugs that have been the object of these studies do not represent a close phylogenetic relationship within the Hemiptera. They belong to various categories, or "series," and are here treated together because they are members of a definite ecological factor, the water. In giving a brief sur- vey of the relationships the writer follows Van Duzee's cata- logue, who, in turn, follows Reuter, 1912. The arrangement and names are those of Van Duzee. Only the Heteroptera are discussed. It is true that certain aphids have been found living on the under surface of lily pads, but they have not been in- cluded. Arranged synoptically Van Duzee's classification fol- lows. In the "Table to Heteroptera" the aquatics are shown in italic type. A. Series POLYNEURIA. B. Supf. Scutelleroidese. C. Phal^^nx Pentafomiformes. Scutelleridae. Cydnidse. Pentatomidse. BB. Supf. Coreoideae. Coreidag. A A. PHLCEOBIOTICA. Aradidae. AAA. ONYCHIOPHORA. B. Supf. Lygseoidese. C. Phalj^nx Lygaeiformes. Neididas (Berytidae). Lygaeidae. CC. Phalanx Pyrrhocoriformes. Pyrrhocoridae. AAAA. ANONYCHIA. Tingididae. B. Supf. Rediivioidess. C. Phalj^nx Enicocephaliformes. Enicocephalidae. (9) 10 THE UNIVERSITY SCIENCE BULLETIN. AAAA. ANONYCHIA— Concluded. CCC. Phaljinx Hebriformes. Hebridae. Mesoveliidae. CCCC. Phal^^nx Nabiformes. Nabidae. BB. Supf. Cimicoideae. C. Phalanx Cimiciformes. CimicidEe (Acanthiidae) . Anthocoridae. Termatophylidse. CC. Phalgtnx Miriformes. Miridae (Capsidae). Isometopidae. AAAAA. TRICHOTELOCERA. B. Supf. Dipsocoroideae. Dipsocoridae (Ceratocombidse). Schizopteridae. C. Phal5(nx Hydrometraeformes. Hydrometridae (Limnobatidae). CC. Phalj^nx Gerriformes. Gerridse (Hydrobatidae). Veliidae. BB. Supf. Leptopodoidea. C. Phalynx Leptopodiformes. Saldidaj. BBB. Supf. Notonectoidese. C. Phalanx Notonectseformes. Notonectidae. CC. Phalijfnx Nepaeformes. Naucoridae. Nepidae. Belostomatidge. BBBB. Supf. Ochteroidese. C. Phalftinx Ochteriformes. Gelastocoridae. (Galgulidae). (Nerthridae). (Mononychidae). Ochteridae (Pelogonidae). A AAAAA. SANDALIORRHYNCHA. B. Supf. Corixidese. Corixidae. hungerford: aquatic hemiptera. a a a a a a a. a uchenorhyncha . Cicadidse. Cercopidse. Membracidse. Cicadellidae (Jassidae). Fulgoridae. 11 aaaaaaaa. sternorhyncha. Chermidae (Psyllidas), Coccidae. Aleurodidag. Aphididae. TABLE TO HETEROPTERA. Series. polyneuria . . . Phloeobiotica . Onychiophora . Superfamily. fScutelleroidese. [Coreoideae Phalynx. . Pentatomiformes . Family. Scutelleridae Cydnidae Pentatomidae . Coreidse . Aradidae . Lygaeoidese. . . Anonychia . Trichotelocera . Reduvioideae. Cimicoideae. . . f Dipsocoroidese . . Leptopodoideae. Notonectoidae... Ochteroideae Ochteriformes fLygaeiformes fNeididae (Berytidae) , •! \Lygaeidae [Pyrrhocoriformes. . . . Pyrrhocoridae Tingididaa Enicocephalif ormes . . EnicocephalidiB Reduviiformes fPhymatidae iReduviidae 1 Hebrif ormes JHebridx I [Mesoveliidx (Nabiformes Nabidas fCimicidae (Acanthiidae) Cimif ormes ] Anthocoridae 1 Termatophylidae Miriformes JMiridae (Capsidae) \IsometopidaB Dipsocoridae (Ceratocombidae) Schizopteridae •J Hydsometraef ormes. . Hydrometridx (Limnobatidae) IGerriformes jGerridx (Hydrobatidae) [ \ Veliidx . Leptopodif ormes .... Saldidx fNotonectaeformes . . Notonectidx { INaucoridse INepaef ormes { Nepidse I Belosiomatidse Gelastocoridx (Galgulids) (Nerthridae) (Mononychidae) Ochteridx (Pelogomidae) Sandaliorrhyncha Corixoideae Corixidse KEY TO HEMIPTERA. (Aquatic and semiaquatic. ) A. Antennae shorter than head. B. Ocelli present; semiaquatic. C. Antennse exposed; front and middle legs similar. Ochteridx. CC. Antennae concealed; front legs raptorial, eyes protuber- ant. GelastocoridaB. 12 THE UNIVERSITY SCIENCE BULLETIN. A. Antennae shorter than head — concluded. BB. Ocelli absent; aquatic. C. Hind tarsi with indistinct setiform claws. (Save Plea, which is less than 3 mm. long.) D. Head overlapping thorax dorsally. Front tarsi 1- segmented, palseform. Corixidse. DD. Head inserted in thorax. Front tarsi normal. Notonectidse. CC. Hind tarsi with distinct claws. D. Membrane of hemelytra reticulately veined. E. Apical appendages of abdomen long and slen- der; tarsi 1-segmented. Nepidae. EE. Apical appendages of abdomen short and flat, retractile. Tarsi 2-segmented. Belostomatidx. DD. Membrane of hemelytra without veins. Naucoridag. AA. Antennae as long or longer than head, exposed. B. Head as long as entire thorax; both elongated. Length about 10 mm, ~ Hydrometridse. BB. Head shorter than thorax, including scutellum. C. Claws of at least the front tarsi distinctly anteapical, with terminal tarsal segment more or less cleft. D. Hind femur extending much beyond apex of abdo- men; intermediate and hind pairs of legs approxi- mated, very distant from front pair. Beak 4- segmented. Gerridse. DD. Hind femur not extending much beyond apex of abdomen; intermediate pair of legs about equi- distant from front and hind pairs (except in Rhagovelia). Beak 3-segmented. Veliidae. CC. Claws all apical, last segment entire. D. Antennae 5-segmented (save Merragata, which has 4). First and second segments of antennae thicker than the others; clavus similar in texture to the membrane, which is without veins; head and thorax sulcate beneath. Hebridse. DD. Antennae 4-segmented. Hemelytra not as above. E. Membrane of wing without cellSjOr db;f6,ro*4 Mesovehidse. EE. Membrane of wing with 4 or 5 long closed cells. Saldidx. Historical Sketch of the Biology of Aquatic and Semiaquatic Hemiptera. The entomologist of to-day, who fails to review the works of the early writers, misses much that would add to his appre- ciation of the age and dignity of his science. The seventeenth century workers were acquainted with some of the wonderful transformations of insects. In the field of aquatic Hemiptera there were notes prior to 1600, but Aldrovandi, in his ''Histor- ium Natura de animalibus," 1618, gives us our first available notes on water bugs. No doubt observations had been made by scientific workers before him, for in Mouffet's ''Insectorum theatrum," 1634, are figures of Notonecta, Nepa and Ranatra. When we recall that Mouffet's information probably came to him in the form of manuscripts handed down through the varying fortunes of time from the great Swiss naturalist, Conrad Gesner, who worked in the first half of the sixteenth century (born 1516, died 1578), we are justified in believing that some knowledge of the water bugs was early achieved. In 1726 Marie Sybille Merian, a lady who was more artist than scientist, brought forth a "Dissertation sur la generation et les transformations des insectes de Surinam." In this she figures the rapaceous habit of a Belostomatid in feeding upon a frog! Frisch (1727-28) brought out the first of a series of ex- tended works that included those of Reaumur, Roesel, De Geer, Goeffrey, etc. He figured under most cumbersome names some of the water bugs. Since his plates are the first creditable ones to appear, those pertaining to water bugs are reproduced on plate IV. ♦ It is unfortunate that Swammerdam's "Biblia naturae" (1737-38) should bear a date later than Frisch, because the work was done some years before his death, which took place in 1680. It is in Swammerdam that we find an argument against spontaneous generation. He was speaking of water bugs, "These water scorpions live in the water all the day, out of which they rise about the dusk of the evening into the (13) 14 THE UNIVERSITY SCIENCE BULLETIN. air, and so, flying from place to place, often betake them- selves in quest of food to other waters. This is always their course when the ditches in which they inhabit come to be dried up. This affords us a satisfactory reason for the great number of insects that immediately appear in the smallest collections of water, since they may very well get thither when it is dark, so that the opinion which ascribes to putrefaction, the power of forming insects, must by this instance of the water scorpion's nocturnal transmigration appear more and more frivolous and unnecessary." Reaumur (1736) unfortunately did not write of water bugs, and Linne (1746-58) busied himself with setting in order our knowledge of natural history. Roesel (1746-1761) published four volumes, well illustrated, and in his work gives some at- tention to the water bugs. De Geer (1752) produced a seven- volume work "Memoirs pour servir a I'histoire des Insectes." A little later Geoffrey (1762) gave his "Histoire abregee des Insectes." De Geer's ''Abhandlungen zur Geschichte der In- sekten," 1778, contains some splendid wood cuts, and in Vol. 3, considerable biological matter on water bugs. Oliver's work appeared in 1782. Fabricius must be mentioned in passing, because of his influence in the realm of the systematic. His "Entomologia systematica" came out in 1794, and his "Sys- tema Rhyngotorum" in 1803. The first five years of the 19th century are memorable ones for students of the Hemiptera. Walchenaer, 1802, published "Faune parisienne, Insectes, ou histoire abregee des Insectes des environs de Paris, etc.," and herein gives biological data on the aquatics. Tigny, 1802, pub- lished a compilation and Latreille gave to the world his splen- did set, "Histoire naturelle generale et particuliere des Crus- taces et des Insectes." Again in 1807 there appeared another of his works "Genera Crustaceorum et Insectorum secundum or- dinen naturalem in familiar desposita inconibus exemplisque plurimis explicata." About this time Wolff and Rossias pub- lished less important works. Thus we find Fabricius, Latreille, Walchenaer, Tigny, and lesser workers producing much work from 1800 to 1805. Lamarck (1816) brought out another large set on insects and other invertebrates. He called his work "Histoire naturelle des animaux sans vertebres . . ." In volume 3 there are some splendid old matters concerning water bugs, notes on progression and feeding. As is often hungerford: aquatic hemiptera. 15 the case, this same year (1816) marks the appearance of Savigny's "Memoires sur les Animaux sans vertebres." It is not, however, in the same class with Lamarck. The following year Leach (1817) published an important paper in the Trans. Linn. Soc. London, and in 1818 Fallen's "Monographia Cimi- cum Suecise" appeared. These are not biological in nature, but must be mentioned because of their important relation to the field. Eschscholtz in 1823, and Le Peletier and Serville in 1825 published works. Meneville (1829) treated water bugs in vol- ume 13, giving colored plates of them in volume 14. Schum- mel (1832) and Laporte (1833) are responsible for a few notes, but a profound and splendid work by Dufour in 1833 marks this period as an important one. His paper, under the broad title "Recherches anatomiques et philosophiques sur les Hemipteres accompagnees de considerations relatives a rhistorie naturelle et la classification des insectes," presented much new and interesting biological data. Two years later Burmeister's "Handbuch der Entomologie" appeared. And in 1836, just a century after Reaumur, we have Brulle's "His- toire Naturelle des Insectes." Volume IX treats of our bugs. Blanchard's set bears the same title and came out in 1840. 1843 is a date to be remembered by all students of the Hemip- tera, for in that year Amyot and Serville set forth in their treatment of the Hemiptera a most thorough review of all earlier work (they omitted Roesel). After one has carefully combed through the early works for biological notes it is most satisfying to see how well these writers digested and set down the work of their predecessors.* Since their time there have been important contributions to the biology of aquatic Hemiptera. Many are the notes and short papers by various writers, but for extensive contributions we are indebted to a few. Uhler, in this country, stands as an early and a most interesting writer on the behavior and habits of this special group. Kirkaldy, in England, published in the ''Entomologist," from 1896 to 1909, a series of articles under the title "Guide to the Study of British Water Bugs." This series should be read along with Uhler as the foundation material for any one taking up the study of water bugs. To these names we should add that of Bueno, who has published more life history studies than any other writer. His writings are most entertaining * Glover has given us in his own handwriting something of the same thing in English. 16 THE UNIVERSITY SCIENCE BULLETIN. and suggestive. He departs from the prosaic in setting forth the behavior of the bugs he has studied. Like Uhler, he takes the trouble to make you go with him to the aquarium or the pool and see the little details of the daily life of the bugs he depicts. In the past few years we have had a number of texts relat- ing to water life, but little that is original on water bugs. Wesenberg-Lund and Brocher stand out as most important foreign contributors to the general biology of the group with detailed studies upon single insects by Dogs, Wefelschied and Hagemann. Much important work on morphology relates to the insect biology, but to enumerate the many truly important papers on mouth parts, genitalia, and the like, would bring us without the limits of this paper. Ecologic and Economic Relations. OUTLINE OF ECOLOGIC AND ECONOMIC RELATIONS. I. Ecology: A. Regions. B. Notes on a few streams and standing waters surveyed. a. Western Kansas. b. Eastern Kansas. 1. Lake View. 2. Haskell Pond. 3. Griesa Pond. 4. Smith Pond. 5. Quarry pools. Rock Pool. Cattail Pool. c. Central New York. 1. Field Station. 2. Bool's Backwater. 3. Ringwood Hollow. C. Two pools and two seasons. 1. A temporary pool. 2. A permanent pool. D. Interrelations within the pool, a restricted environment. a. Haunts and Habits. b. Habitat Key. c. Relation to other organisms. 1. Parasitism. 2. Oviposition in plant tissues and upon animals, 3. Relation to other organisms largely a question of feeding habits. II. Economic Importance. ECOLOGY. REGIONS STUDIED. Three distinct types of country with their attending water bodies have been surveyed in connection with these studies on the water bugs : Western Kansas, Eastern Kansas, and Cen- tral New York. Western Kansas is a high, dry, level land. Its vast plains are little broken by the eroding forces of the water and the (17) 2 — Sci. Bui. — 1669. 18 THE UNIVERSITY SCIENCE BULLETIN. vista is unmodified by timbered tracts. The rivers are but slen- der threads of silver, v^ending their way through wide strips of sand, margined by shallow banks. The lesser streams are little more than connected series of pools, which, if spring fed, may survive the drouths of summer. The meandering chan- nels of these latter are mere ditches bordered by narrow meadows lower than the surrounding level and covered with a more luxuriant growth of grasses. The region, however, is not without interest for the student of aquatic Hemiptera. The sandy stretches by the river channel abound with toad bugs and Saldids, while the pools along river and stream course are populated by the true aquatics. Eastern Kansas is more varied in its topography. There are stretches of upland plain, wooded slopes and rich alluvial hood plains. The rivers meander through wide valleys, dropping their never-ending burdens of silt in every stretch of slackened water, to add to the already obstructed channels. The waters of the region are typically muddy. The standing waters con- sist of oxbow lakes and artificial ponds. These depend upon the runoff of the land for maintenance. Now and then a clear spring-fed pool may be found in some stream near its source, but such a pool is by no means common. There is plenty of water for a study of those forms of aquatic life that thrive in muddy, quiet waters. The spring freshets give rise to numer- ous temporary pools that linger until the dry days of summer lap them up, and these present an interesting study of tran- sient and indigenous populations that spring up, flourish for a time, and disappear with the passing of the waters. Central New York presents a marked contrast to the fore- going. It is a region of great, rolling, wooded hills, with up- land bogs and marshy meadows, spring-fed pools and sparkling brooks, deep ravines with water falls and rapids, and finally, narrow valleys with their scant flood plains and lake-confining basins. Here indeed is a wealth of water types. To one accus- tomed to collecting in the sluggish streams and artificial ponds in Kansas the environs of Ithaca, N. Y., afford a rare oppor- tunity. Here, within easy reach of the city, are to be found all gradations from well-areated, rushing, tumbling waters of the brook to the dark, acrid, sluggish streams of the upland bog; from spring-fed pools to lake conditions. Thus, of the three types studied, this last presents, by far. hungerford: aquatic hemiptera. 19 the richest fauna for the student of inland waters. It would be interesting to note the characteristics of each pool or stream surveyed in the course of these studies, from west to east, but time and space will not permit. A few types are described here and in the body of the text and a few photographs pre- sented to indicate the nature of the water bodies. See Plates I and II with attending legends. NOTES ON A FEW STREAMS AND STANDING WATERS STUDIED. Westerm Kansas. Collections have been available from every county in the western half of Kansas, but only the thirteen counties north and west of Lane county have been surveyed by the writer. This region is drained by three rivers and their tributaries. The Republican river and its branches, Beaver, Sappa and Prairie Dog Creeks, cover Decatur, Rawline, Cheyenne, Sher- man, and most of Thomas counties. The Solomon arises in Thomas county and passes through Sheridan, while the Smoky Hill drains Wallace, Greeley, Logan, Wichita, Scott and Gove counties. Most of these streams are intermittent, often sinking into the sands of their channels during a dry spell. At the time collections were made near Russell Springs, in Logan county, the Smoky Hill river was a stream eighteen inches broad and from one-half to three inches deep on a bed of sand several rods wide. A few pools were found where water bugs could be col- lected. Several weeks later, when we were camped farther up the river in Wallace county, the stream had ceased to flow. The camp was set under a few willow trees on a sandy flat some distance from the channel and several feet higher than the normal water mark. This sandy stretch, close to the place where the water should have been, was splendid collecting for Toad bugs. There was no vegetation or other shelter to ob- struct collecting. A few nights after arriving at this place a rain up-stream caused a great change. The entire flat, includ- ing our camping place was covered with water very shortly. We concluded, from this experience, that the vicissitudes of the inhabitants of the sandy stretches bordering western Kan- sas rivers must evidently be great — one hour upon dry sand and the next submerged beneath a seething torrent of water. 20 THE UNIVERSITY SCIENCE BULLETIN. Such a catastrophe did not disturb the Gelastocorids, for they were out again as soon as the waters sufficiently receded. (Plate II shows a photograph of a western Kansas river.) Eastern Kansas. Collections were made in the pools and ponds about Law- rence. Lake View, the largest standing body of water avail- able, is six miles from the city. This occupies an abandoned channel of the Kaw river, and is, in fact, an "oxbow" lake. This strip of water is perhaps 150 yards across and a mile long, fringed by willows along the sides and encroached upon at the ends by cattail, scouring rush and other plants. A thorough survey has never been made of this place. Haskell Pond : An artificial pond covering perhaps half an acre. This pond has a muddy bottom and little vegetation. It is fed by the runoff of the land and by a little intermittent stream that has its origin in some springy ground in a mow- land meadow above the pond. This stream, a mere ditch, over- grown by tall marsh grass, contains several water holes that have been good collecting for water bugs, especially for Belo- stoma. Griesa Pond : A little dammed-up pool of very muddy water, in extent perhaps, three rods long and two broad. This is lo- cated in a five-acre lot and invaded by two or three cows in fly time. Since the bottom consists of deep, fine silt these visita- tions keep it ever turbid and filthy. It was in this pond that the Ramphocorixa and the egg-burdened crayfish were most abundant. Smith Pond : Of the same type as above, but less muddy, being located in a pasture and so situated as to receive less silt. It is more than three times the size of the Griesa pool, and perhaps four feet in its deepest part. There are no seed plants growing in the pool. Unicellular algse make its waters green in midsummer. Entomostraca became exceedingly abun- dant here one dry summer, and the pond was teeming with thousands of the back-swimmers of the genus Buenoa. The Quarry Pools : Two temporary pools, occupying depres- sions where limestone had been quarried, were visited one season almost daily from earliest spring until they disappeared. The two pools were quite different. One named the Cattail pool was surrounded by cattail. Its waters were clear and hungerford: aquatic hemiptera. 21 contained considerable growth of Spirogyra. One side was bordered with spike rush, Eleocharis obtusa. This little pool, a rod wide and perhaps three long, of clear, open water, proved the best collecting ground of any of those studied. Hydrome- tra martini, Microvelia borealis, Mesovelia mulsanti and Gerris marginatus patrolled the waters and floating rafts of algae. Arctocorixa alternata and Notonecta undulata were dominant within the pool. Ostracods, the basis of the food supply for the young back-swimmers and for the smaller surface forms as well, were present in astonishing numbers. (See Plate I for photograph.) The other pool, called the Rock Pool was roughly a rod square and contained no vegetation save a mar- gin of spike rush and sedge, the outermost procumbent stems of which floated upon the water and made footing for the Mesovelias that dwelt about the pool. The water soaked stems of this rush were, more than those of any other, employed by the Mesovelias in oviposition. This pool contained many Co- rixids but fewer back-swimmers than the Cattail Pool. All of these pools, save the first, are within five minutes ride from the writer's residence, and were visited several times a week throughout the season. Several other bodies of water, the Brick Plant ponds and Bismarck Grove pond, were surveyed frequently. These waters occupy several acres in extent, are devoid of vegeta- tion, and afforded less satisfactory studies than the smaller pools. They are shown in the photographs, Plate I. Central Neiv York. The principal waters studied were within easy reach from Cornell University. Since the true water bugs are seldom found in running waters, the frequent surveys were confined to the quiet waters. The Field Station: This is located in the marshy meadows at the south end of Lake Cayuga. It is surrounded by a sys- tem of pools, some isolated, others connected by outlet to the lake. The isolated pools were newly made and contained few bugs, other than the back-swimmers. One pool, close by the station, was fed by a f owing well and its waters contained quantities of Elodea and other aquatic plants. This pool was open most of the time throughout the winter, and was ever a place to collect water bugs in great numbers. Four species of 22 THE UNIVERSITY SCIENCE BULLETIN. Notonecta, the little Plea, and Corixids in both numbers and variety were here. Ranatra and Nepa, too, came into the catch often enough to call them plentiful. Of all the places the writer has ever collected, this pool in late fall and early winter has been the best collecting. East of the Field Station there is a little stretch of water, connected with the Fall Creek outlet, in which there is a dense growth of water shamrock in summer. In midsummer the floating leaves of this plant make footing for the surface forms such as Mesovelias, Microvelias and Hebrids. In earli- est spring the brown tangle of the stems of the previous year's growth harbored hundreds of Notonecta variabilis. These scattered to other regions for breeding purposes and were not abundant in June. Bool's Backwater: A very few minutes brisk walk east of the Insectary at Cornell takes one about the border of the Beebe Lake and across a couple blocks of Forest Home to a steep bank overlooking a strip of land bordering an abandoned channel of Fall Creek. This old channel can be followed to its junction with Fall Creek at its upper end. Near this point arises the first of a series of clear pools which are fed by seepage from Fall Creek, by springs or by both, and which, in turn, overflow to form a little brook that trickles along over large water-worn stones covered by vast quantities of brown gelatinous growths of diatoms, to come finally to the quiet body of water filling the old channel for a considerable dis- tance back from its union with Fall Creek, due to the dam- ming of the latter a short way below. This is Bool's Back- water. Its waters are fresh but still, and great beds of Elodea and Chara occupy ever-increasing areas as the season ad- vances. The bottom is somewhat muddy and the shallow mar- gins deeply covered with a flocculent organic ooze, ideal food for the boatmen. And here, indeed, two species of Corixids were to be taken in countless numbers. Because of this fact and its accessibility, this place was chosen for daily observa- tion and notes taken on these frequent visitations are else- where recorded. Ringwood Hollow : A series of interesting pools and marshy meadows in Ringwood Hollow were visited at rather frequent intervals throughout the season. These were reached by a short ride on the train, followed by perhaps three miles of walking. hungerford: aquatic hemiptera. 23 The area contains a pool in a springy pasture meadow, and Winterberry pool, a shallow bit of water overgrown with clumps of winterberry bush and encroached upon by procum- bent moss-covered masses of the fallen trees of former days. This water in midsummer was solidly overgrown by duck- weed, which made satisfactory collecting difficult Aside from a few Belostomatids this was not good collecting. To the west of this pool are two others, nearly circular in outline, and occupying depressions doubtless made by tardy ice blocks, as the glaciers left the land. These are in a wooded tract and their bottoms are deeply strewn with leaves. They were good collecting for water bugs in early spring, but with the advancing season they were abandoned by the bugs for more favorable breeding places. Occasional trips were made to Dwyers ponds and a splendid pool on Six Mile Creek, but with less of the regularity followed in surveying the others. TWO POOLS AND TWO SEASONS. Attempts have been made to follow very closely the ad- vancements of the season in nature. To do this successfully certain pools have been selected and surveys recorded at fre- quent intervals. From the field notes in this connection one is impressed by the varying fortunes of the life in a pool during the course of the season. Some of the notes taken in connection with two studies are here given because they show the history of two pool types, one a temporary Kansas pool and the other a permanent body of water in New York state. A Temporary Pool. The pool described above as the Cattail pool was visited regularly from early March until July 28, 1916, when all the water had disappeared. This pool was visited November 20, 1915, at which time there was no water in the pool and little of interest found save that the cattails were covered with large black plant lice and their orange-colored eggs. A few large spiders were hiding beneath the leaf sheaths of the cattail. No water bugs were found, though the debris was not sifted. In the Smith pond near-by, adult Notonectids, Corix- ids and Belostomids were taken in numbers. The melting of the snows during the winter supplied the basin of the Cattail pool with water again, and the first warm 24 THE UNIVERSITY SCIENCE BULLETIN. days of March found Notonectids and Corixids flying to it from the Smith pond. By the last of the month Corixids were laying eggs. April 11 there were not many adult bugs where they had been exceedingly abundant before. The back-swim- mer eggs were showing red eye spots. By May 4 the pool was full of activity. Ostracods were exceedingly abundant and Notonectids in first and second instars were preying upon them in numbers. Gerrids in second instar were upon the water and many marshtreaders were upon the floating dead leaves of cattail, mats of algae and sprouting masses of cattail seed. Corixids from the first to the fifth instar were abund- ant, but perhaps the larger number were in the third and fourth instars. A few adults were present. The tenth of May was a fine warm day and the Cattail pool was a great place to study young water-bug life. Droves of Gerrid nymphs and marshtreaders made the surface seem a busy place in- deed, while the Corixid and Notonectid nymphs were in droves within the water. It was May 17 before the first adults of the spring crop of water bugs were noted in this pool. These were new fledged Corixids. It was May 25 before the Gerrids and Notonectids attained the fifth instar in numbers, and at this time a new bug was dominant upon the floating vegetation of the pool. This was the new adult generation of Mesovelia midscmti, and the presence of large numbers of these silvery- winged forms brought them at once to the attention as they moved about over the green algae. The green nymphs had at- tracted little attention in the same situation a few days be- fore. On May 28 most of the Corixids were adult and the pool was roily from a recent rain. The young Marshtreaders were out in force upon this date, and were rivals of the Meso- velias for prey. May 30 the Gerrids were transforming, and the next day the first back-swimmers were seen to emerge into the adult state, yet there were nymphs from first instar up. On the morning of June 3, the notes show that the cattails were in bloom and young plants were encroaching upon the clear water space very steadily. From this day's record and a comparison of the notes of other days regarding the appear- ance of the stages of the water insects, one is impressed by the remarkable synchronism of development, not only of the water bugs, but hand in hand with them, of the water beetles. And here we find the flowering of the cattail heralding the advent of hungerford: aquatic hemiptera. 25 a new generation of water bugs. True, many of the bugs an- ticipate this, especially the Corixids, and many of the back- swimmers are tardy, but as a whole, when the cattails bloom, adults of the spring generation of water bugs are at hand. For days the water had been surveyed for eggs, but none found until on June 17. Corixid eggs were present in num- bers. Now, indeed, the days of the pool are numbered, the cattails are steadily encroaching from the west end, and the spike rush bunches are advancing. This restricts the range of true aquatics, but leaves the marshtreader and Mesovelia dominant above. A rain enlarged the pool a few days later, but did not change the circumstances of the life above or within, and after a few days the recession of the pool was resumed. July 8 the water extended only to the edge of the great cattails. Eggs of Corixids and Notonectids were now to be seen again, and the surface was surveyed by both the striders and treaders in numbers. Surely there must be some truce among these keen com- petitors of the surface ! For here they are all eager for food and not one with scruples against pouncing upon a weaker brother, yet getting on together — a heterogeneous collection from the large Gerrid to the tiny Microvelia. How they man- age to maintain an armed truce and survive by their alertness only patient observation can discern. How often have we been able to study the undisturbed pop- ulation in the early morning hours when food getting seemed their chief concern! There were the nervous jerky-gaited Gerris nymphs, the agile Mesovelias and the deliberate, stalk- ing Hydrometra. The Gerrids are truly powerful enough and quick enough to clear the waters of their competitors! Why do they not do it? Because, if we may judge from their behavior, there is some mutual aversion that is overcome only by an occasional ravenous appetite. On several occasions, when some bug was intent upon an activity that distracted its usual vigilance, it was caught by a larger bug only to be re- leased again without apparent injury. The capture of a pair of mating Hydrometra by Gerris marginatus and their sub- sequent release is a fair illustration. Mesovelia females at- tacked while ovipositing were invariably released unharmed. Many instances of the stealthy approach of some predator with ill intent to its prey have been watched with fear for the 26 THE UNIVERSITY SCIENCE BULLETIN. safety of the unwitting victim only to see the incident close v^ithout an actual attack or with but a brief retention of the captured. But the above note is beside the issue, and should, perhaps, have been omitted along with the many interesting incidents recorded in the field notes that can find no place in the printed record. It was noted on July 8 that the pool was restricted by the great cattails on its western margin. By July 14 it was reduced to a few little puddles in depressions made by boot tracks on former visits. Hundreds of little Microvelias, Mesovelias and a number of Hydrometra had followed the waters to these re- treats. Saldids were present upon the moist ground round about, while within the water a few Corixids and Notonectids still managed to survive in the ever diminishing quarters. The following day one puddle of water yet remained, a little patch of surface 6 by 10 inches, and upon it crowded together thir- teen adult G. marginatus, a myriad of winged Mesovelia and a host of Microvelia in all stages. They were making their last stand upon the element that bound them together in common interest. The end of it all was very near. Whither would they go when the last drops sank into the ground, or were taken up by the sun's hot rays? The writer wanted to know. The back-swimmers and boatmen were gone, and even the nymphs disappeared without leaving a carcass. What became of them? There is no clue. Perhaps the adults flew to other quarters while the nymphs in their close confines fell the pre^^ to sur- face forms. There was only one other possibility, and that a small one. Had the nymphs buried themselves in the mud? To find the answer to this, on July 21, when all the water was gone, the place was visited with a horse and wagon and the mud from the bed of the pool placed in tubs and taken to the laboratory. No living thing was likely to escape, for the mud was only 6 inches deep upon a base of lime stone. Live ostra- cods were numerous beneath the wet cattail leaves that were prone upon the mud, but no true aquatics in evidence, nor yet their eggs. About the young cattail clumps a few Hydrometra lingered, but the abundant life of a few days previous was gone, leaving no trace of its going nor making any provision for a repopulation by its progeny should timely rains revive the place. No eggs hatched from the rushes or cattail brought in hungerford: aquatic hemiptera. 27 and no water bugs came forth in. the pool transplanted in the laboratory. Thus the "Cattail Pool" comes in the category of the temporary pools that provide range for a spring generation of bugs, but afford no permanent abiding place for this nur- tured population. A Permanent Pool. The writer is unable to say what has been the past history of BooFs Backwater at Ithaca, New York, but from the topog- raphy of its location and the prevailing climate he believes it to be more or less permanent in its nature. The chief interest in this pool was the presence of the over- wintering fourth instar nymphs of Palmocorixa buenoi in large numbers. There were some other corixids but not in confusing numbers, and the place was chosen to follow the development of the P. buenoi in nature. Near the upper end of this Backwater there was a little shallow pool connected by a narrow neck of water to the main body during normal times. A constant stream of fresh water came into the main body near by, but made connection with this little pool only in times of high water. The nymphs of Palmocorixa were here by hundreds. Twenty-three were counted as they foraged in a space two square inches in extent. Under the life history of Palmocorixa will be found the ad- vancement of the development of these bugs. April 19 the Arctocorixa alternata were mating while the P. bueyioi were still in the stage in which they overwintered. May 9 a wind from the northwest backed the water up so that the little pool was broadly connected with both the Back- water and the Bool's brook. Yet when it was examined the boatmen were seen upon their former foraging grounds though the shore line was several feet beyond the normal. May 11 the water was backed to its former level again. Toward the last of the month the little pool was obliterated by high water for several hours at a time but without changing the population to any great extent. Polliwogs and minnows invaded the pool in early June, and there was some concern as to the effect the latter would have upon the corixid nymphs which were now attaining the adult state. June 8 the water was two feet highei' than usual, and for the next week the shore line was six feet out from the normal. The grass along the east bank of the Backwater was submerged and came to be slime coated with 28 THE UNIVERSITY SCIENCE BULLETIN. the result that the Corixids came to occupy the added forage grounds in this shallower water, for Corixids are lovers of shoal waters and adapt themselves in time to the oscillations of the pond in which they live. The species of boatmen studied pos- sessed no functional wings and must as a rule be bound to permanent water. But permanent water does not imply that the life within is not subject to varying fortunes and conditions as shown in the notes on Bool's Backwater. For this pool would be threatened with unsightly patches of filamentous algse during extended dry hot weather, but be cleansed again with the next rains. And these factors enter into the life of the organisms within its waters. INTERRELATIONS WITHIN THE POOL. When one undertakes to study the adjustments of any one set of organisms to each other he finds the field restricted and unknown on every hand. He may pursue disturbing factors into other groups only to find these factors held in balance by still other causes, and so ad infinitum. Not an organism of the pool can escape the influence of its fellows, and no final analysis can be reached till all are understood. . The pool is indeed a restricted environment and yet only the more obvious facts are known concerning the life within it. In introducing, therefore, a few ecological notes relating to the water bugs the writer has not the temerity to claim more than a designation of the more apparent features. These are considered briefly in the following outline : a. Haunts and Habits. h. Habitat Key. c. Relation to other organisms. 1. Parasitism. 2. Oviposition. 3. Feeding habits. While the relation of the water bugs to other organisms is largely a question of feeding habits, it is well to consider first of all the relative location of each form. Haunts and habits determine in large measure the range of influence of each unit in the environment. In another chapter the families of water bugs are enumer- ated. There are thirteen of them. Four are limited in large measure to the moist shores adjacent to the water. Two live upon the rafts of algae and other vegetation floating out from hungerford: aquatic hemiptera. 29 shore. Two row over the open waters, and five lead a sub- aquatic life. The first eight are called semiaquatic, the last five true aquatics. The general distribution of these forms is shown in the synoptic table. There are some exceptions, and some structural details have been added to identify genera, so that the table cannot be called purely ecological. HABITAT KEY TO THE AQUATIC AND SEMIAQUATIC HETEROPTERA. A. Upon the shore; not running out upon the water, although they may alight there. B. Escape by quick jumps and short flights. Antennae longer than the head. Saldidse. BB. Escape by hopping, flying or concealment. Antennae shorter than the head. C. Beak very short. Gelastocoridse. CC. Beak longer. Ochteridse. AA. At the water's edge, running out upon the water when disturbed. (Often found upon rafts of floating vegetation.) B. Very small plump-bodied bugs, usually black and silver, or mottled with brown. C. Antennse 4-segmented. D. Tarsal claws anteapical. Veliidae. (genus Microvelia.) DD. Tarsal claws apical. Hehridx. (genus Merragata.) CC. Antennae 5-segmented. Hebridse. (genus Hebrus.) BB. Fairly slender green or yellowish-green bugs. Mesoveliidae. BBB. Very slender, elongate bugs. Hydrometridse. AAA. Coursing upon the water by quick, jerky movements. B. Fresh water. C. On quiet or moderately flowing waters. D. Medium to large insects. E. With distinct abdomen. Gerridse. (genus Gerris.) EE. Without distinct abdomen. F. Color uniformly dark. Gerridse. (genus Metrobates.) FF. Color dark, pictured with yellow. Gerridse. (genus Trepobates.) 30 THE UNIVERSITY SCIENCE BULLETIN. AAA, Coursing upon the water by quick, jerky movements — Concluded. DD. Small, dark insects, with long, slender legs. Gerridse. (genus Rheumatabates.) CC. On moderately rapid streams or little bays and eddies connected therewith. Veliidse. (genus Velia.) CCC. On the riffles and rapids. Veliidm. (genus Rhagovelia.) BB. Marine. Sometimes far from land.^*-'^^'^'^*' Vajowrftg. (genus Halobates.) AAAA. Living within the water. B. Clinging to supports and remaining in contact with sur- face film. C. With long respiratory tube at caudal end. Nepidie. D. In tangled trash (elongate). (genus Ranatra.) DD. In the mud and trash; broad, flat. (genus Nepa.) CC. With short, retractile respiratory tube at caudal end Belostomatidse D. Length 1 inch or less, often carrying egg clusters in summer. (genus Belostoma.) DD. Length, 1% inch or more. E. Very large bugs, with fore femora grooved. (genus Lethocerus.) EE. Very large bugs, with fore femora not grooved. (genus Benacus.) BB. Free swimming. C. Swimming upon their backs, often resting with tip of abdomen at surface. Notonectidse. D. Very tiny, plump, little creatures, found clinging to aquatic plants. (genus Plea.) DD. Larger forms. E. Slender bugs, with eyes parallel, dwell- ing for most part in open waters, where they swim submerged. (genus Biienoa.) EE. More robust bugs, resting with tip of abdomen at surface or clinging to sub- merged vegetation. (genus Notonecta.) hungerford: aquatic hemiptera. 31 AAAA. Living within the water — Concluded. CC. Swimming in normal position. D. Clinging to vegetation or swimming through the water with a steady motion. Naucoridse. DD. Resting on the bottom, rapid, darting swim- mers. Corixidse. PARASITISM. Very little has been recorded regarding the parasites of the water bugs. All of them, in all of their active stages, are sub- ject to the attacks of the Hydrachnids. These little water mites attach themselves to the bug and remain until adult, when they molt their last nymphal skin and become free swim- ming. These parasites are often very abundant upon a host, so abundant that they inhibit growth and interfere with the progression of the insect. They are particularly numerous on Ranatra and sometimes disarrange the normal functioning of the caudal air-filaments, as shown in figure 10 on plate XVIII. Corixid nymphs have been noted to show a stunted growth and diificulties in molting, due to the presence of these para- sites. Under the discussion of the biology of the Corixidse is given an account of the seasonal abundance of Hydrachnids. According to Kirkaldy, who was a careful student of aquatic Hemiptera, the water mites lay their eggs in spring in in- cisions in soft stemmed aquatic plants or on the underside of leaves. The young larvae are pale red, and possess six legs, each of which is six segmented. They fasten themselves to water insects by means of sharp hooks at the end of their palpi. Once fixed the head and mouth parts stretch until they become separated by a neck from the main body, the transpar- ent skin of which rapidly swells and elongates to form a bag, with the more solid dark red parts visible anteriorly. The elongated maxillse penetrate and extend beneath the chitinous covering of the host until they form a long, pointed thread. The legs curl up and become useless and are more or less with- drawn. The larva gradually passes into the pupa stage within this bag, which becomes more and more swollen and rounded posteriorly, and finally bursts to release the adult eight-legged mite. This swims actively about for a time, but before at- taining maturity fixes to some plant and undergoes another molt without material change of form. Soars, 1901, discusses 32 THE UNIVERSITY SCIENCE BULLETIN. the "Larval water mites of aquatic animals" in the American Monthly Microscopical Journal, Vol. XXII, pp. 323-324, and a key for determining Hydrachnids is to be found in "Fresh Water Biology," by Ward & Whipple. Besides the mites an undetermined internal parasite has been discovered in the body cavities of Notonectids and Cor- ixids. These the writer has frequently seen, as well as spher- ical spore cysts of a gregarine to be found in the body cavity of Corixids. Parasitism by Hymenoptera has been observed in a very few cases. These have been egg parasites and belong to the following families : Chalcididse, Proctrotrypid^e and Myma- ridse. In the first family we have the frequently mentioned Prestiuichia aquatica Lubbock, which has been reared from the eggs of Notonecta and Ranatra as well as those of beetles. In the Proctrotrypidae there are recorded two species at least. Limnodytes gerriphagus March and L. setosus De Ste- fani Perez, both of which parasitize Gerris eggs. Matheson and Crosby reared the former species from the eggs of Gerris remigis in June, at Ithaca, New York, and also a Mymarid, Cai'aphractus cinctus Walker from eggs which they found inserted in the tissues of plants on December 7. On December 19 some young back-swimmers were swimming about and also some of the little wasps had emerged and were actively swim- ming in the water. As many as four parasites emerged through one opening in one egg. This parasite uses its wings in propelling itself through the water. The fact that these notes were made upon eggs inserted in plant tissues and taken in the winter time, limits the host species to N. irrorata or one of the Buenose, and throws new light upon the wintering of back-swimmers. The species above mentioned are known to winter as adults, though the presence of eggs is not impossible, for one of the European Notonectids is known to pass the winter months in the egg stage. The field of study along these lines would well repay investigation. Brocher has also recorded a hymenopterous parasite from the eggs of Hydrometra. Doubtless there are many other parasites to be found by careful rearing. No internal parasites of either nymphs or adults of any of the water bugs have been reported in the literature so far as the writer knows. HUNGERFORD: AQUATIC HEMIPTERA. 33 OVIPOSITION. The oviposition of the aquatics and semiaquatics does in large measure consist in affixing the eggs to some inert sup- port in the water. Yet there are two conditions wherein other organisms are involved. One, in those cases where the eggs are placed in incisions in plant tissues, and the other where the eggs are deposited upon some animal form. In the former case the plants are directly concerned. So long as the eggs are merely glued to living plants for support, a safeguard against their loss in the bottom of the pool, they are not considered disturbed by the relation, but when their tissues are punctured and lacerated in the process, there enters a mutual ecological relation. The Hebrids and Saldids cache their eggs beneath the leaf sheaths of bog-moss and sphagnum, while the latter employ the shore, grasses as well. Mesovelia and Rheumatobates are equipped to puncture plant tissues, and the fact that Mesovelia imbeds her eggs in the stems of spike-rush and leaves of cat- tail, has been elsewhere recorded. Members of each of the genera of the Notonectids can be found that make incisions in the stems of money wort and other submerged plants for the reception of their eggs. Two species of the genus Notonecta in this country, N. irrorata and N. lutea* Buenoa margaritacea and Plea striola come in this class. The matter of the Corixid that in large measure attaches its eggs to those portions of the body of the crayfish which are bathed by water currents, is discussed under the biology of Ramphocorixa acuminata. (See page 218.) The eggs of this boatman have been found upon smart weed stems of uprooted floating plants and upon dragon fly nymphs, but in very small numbers compared to those affixed to the crayfish. Other Corixid eggs have been found covering the shells of living snails, etc., but in such cases little ecological significance can be attached to the phenomenon. FEEDING HABITS : THEIR RELATION TO OTHER ORGANISMS. The aquatic and semiaquatic Hemiptera are, as a group, no- torious predators, and the records from an early date are re- plete with accounts of their voraciousness. The observations * Judging from equipment of female. 3— Sci. Bui. — 1669. 34 THE UNIVERSITY SCIENCE BULLETIN. noted, however, deal in large measure with their prowess in mastering insects and other animals larger than themselves. Thus the textbooks on Entomology state the the aquatic Hemip- tera are without exception, predatory. We are led to believe that those which dwell upon the surface lead a precarious existence, subsisting upon such uncertain fare as the accidents of nature may provide. In other words, that their food supply consists in the capture of such flies and other terrestrial insects as may chance to fall into the water. One writer in fact has stated that Gerris shows no response to forms meeting the surface film from below. This, however is not in keeping with the frequent observation that Gerris will strike for a back-swim- mer nymph that comes to the surface close by. The writer has pointed out that the food of our common water-strider Gerris marginatus consists at certain times of the year almost exclusively of the Cicadellids (Jassids) and related forms that feed on Juncus and spike rush, bordering on and growing in the shallow waters. In checking over the field notes on the feeding habits of these insects, it is seen that much of their food is produced close at hand, both within and about the pool. So, also, with the "toad-bug" Gelastocoris ocu- latus, which has been taken feeding upon lace bugs (Tingi- didx) reared close by. Our common species of Rheumatobates, while it does not disdain to feed upon small insects that fall into the water, ob- tains its main supply from the little crustacean forms such as Ostracods and Daphnians which swarm the quiet pools. These it captures as they rest at the surface, scooping them out and holding them aloft upon the upturned tip of the beak, while the body of the little victim is being depleted of its nutritive ma- terial. The little Microvelia borealis, common in Kansas, has access to the same source for its food supply and similar habits of consuming it. Mesovelia mulsmiti has been observed exploring the sides of stems of rush and cattail that floated upon the sur- face for Ostracods, which it occasionally obtained, while Hydro- metra martini stalks about over the floating vegetation in search of whatever small beings chance to come to the surface film. Its victims have been observed to consist of mosquito wrigglers, mosquito pupae, emerging midges, nymphal Corixids, and Ostracods, as well as small terrestrial insects floundering on the water. hungerford: aquatic hemiptera. 35 As far as the true aquatics are concerned, according to the texts, which must of course rely largely upon the published records, one and all feed upon insects and other animals in the water. The tendency of the reader, however, is to gather the impression that the prey is large. This is not always true. The large Belostomatids, no doubt, consume considerable num- bers of snails, while! the bulk of the food of the first three or, four stages of Notonectse consists of small Crustacea: Ostracods, Cyclops and Daphnians with the addition of such other forms as they are able to master. In one genus of back-swimmers, the Buenoa, the adults as well as the nymphs, feed very largely upon small entomostracan forms. This is also true of the little Plea. Corixids on the other hand find the source of their food supply in the brown sedimentary material on the bottom of the pool. This they scoop up with the flat rakes of their forelegs. These rakes are somewhat spoon-shaped termi- nal segments or palse, which are most admirably equipped for their work. The details of the feeding habits of the boatmen are given elsewhere. It is only necessary to call attention here to the fact that they are not predatory in the ordinary sense, that they will strip the chlorophyl from a filament of the spiro- gyra quite as readily as to gather in the flocculent ooze of the bottom of the pool with its attending population of diatoms, desmids, Euglense, Scenedesmus, organic debris, and the Pro- tozoa, rotifers and oligochsetes it may contain. Thus the role played by the aquatic Hemiptera in the society of water forms indicates an intimate relation, not only to the larger beings, but to the smaller Entomostraca and even to the unicellular life of our ponds and pools as well. It is further to be noted that, while some, like the water striders and back-swimmers, many take advantage of help- less terrestrials upon the water when opportunity affords, the water and its surrounding vegetation supply their chief de- mand. ECONOMIC IMPORTANCE. In these utilitarian days one -is asked first of all in regard to the value of his results. If all could but have the vision as Professor Dawson has expressed it in a recent number of Science!* * "University Ideals and their Limitations," by Professor Percy M. Dawson, in Science, N. S., vol. XLVIT, p. 547. 36 THE UNIVERSITY SCIENCE BULLETIN. "The scientific attitude is not only agnostic, but also universal. To the scientific mind there are no isolated facts or discrete phenomena, but all are integral parts of the great structure of knowledge. To him the separate sciences and subsciences become of importance' and signifi- cance only as he sees them as elements of more comprehensive units, which in turn make up the ultimate unit which he calls Nature, Weltan- schauung or world picture." A further justification would be unnecessary. Bueno, in a little paper on the "Ways of Progression in Waterbugs," Ento- mological Netvs, 1906, concludes with the following lament: "The meagreness of information regarding these habits has led me to the studies outlined above. It is to be hoped that the rising genera- tion of entomologists may give a little less time to hair-splitting classi- fications and devote its energies to investigations of habits and life histories of other than economically important groups, or than those which, like butterflies, are largely aesthetic; and to such lovers of the insect folk do I look for further light on these highly interesting but financially unremunerative subjects." The ecological significance of forms has come tardily to the agricultural and horticultural entomologist, but it has come indeed to make a profound impression, as the deeper relations have been understood. It will come more speedily as the farming of the waters takes a larger place in our activities. The problems here are different and the factors so diverse and unknown, that any light upon the interrelationship of aquatic societies will stand as a substantial contribution to the ulti- mate solution of the baffling problems of the present. The observations of Swammerdam concerning the preda- tory tendencies of the water bugs has been followed by numer- ous records. Merrian graphically figures a large Belostomid in the act of eating a polliwog. Thomas (1871) cites a Corixid as eating fish eggs. Earlier writers mention Corixid eggs, and their use as food by the Mexicans. A few writers indeed have written upon the economic importance of water bugs. Thus Kirkaldy, in an article on "An Economic Use for Water- bugs" (1898), devotes himself to an account of their use as food, and the following notes are from this paper. Thomas Gage (1625), who traveled in Mexico, mentioned the sale of cakes made of a "kind of froth" from the Mexican lakes. Thomas Say (1832) said that the adult Corixids were used as food in the City of Mexico. Guerin Meneville (1857) publlished a long account on this subject in some five journals, and Virlet d'Aoust (1858) gives a review of the same subject. hungerford: aquatic hemiptera. 37 The gist of the matter appears to be that at the proper season bundles of rushes are placed in the shallow lakes and upon these the eggs named by the Mexicans "Axayactl" or water- face, are deposited, gathered by the natives and made with meal into cakes. These are eaten au natural or with green chilis! They are also cooked without further preparation, having then the appearance of fish roe, when they are called "Auhauhtli" or water wheat.' They are said to have a delicate flavor and not to be disdained at fashionable tables. Kirkaldy stated that the dried ova and bugs were being imported into England by the ton for food for fishes. Aside from these ''direct benefits" from water bugs, the numerous notes, such as "A Ferocious Water Bug" and others that have appeared from time to time, record isolated bits of behavior of value in the final summing up of their status. In a study of the biology of this one group of aquatic organisms some facts of economic value have been brought to view. We have before us now more knowledge concerning the place of the water bugs in the complex of this new field of agri- culture than before. Pisciculture, an important branch of this field, is affected, we find, not only by the killing of the young fish by the larger predatory bugs, but by the fact that the majority of them are contenders for the same entomostracans that make up the bulk of the food supply of young fishes. One group of bugs, indeed, themselves afford some possibility of providing forage organisms for the fish culturist. This is the water boatman, which has been found in the stomach con- tents of a number of fishes and which forages on the organic ooze, Spirogyra, and other lower organisms of the ^ool. Form and Function. Of all the ecological groups of animals none shows more splendid and ofttimes obvious adaptations of form to function than do those that live in the water. Surrounded by a re- markably uniform element, it is interesting to note how ani- mals of the most diverse classification have been molded to a common plan in response to the physical properties of the medium in which they dwell. Not only have widely different organisms responded in a similar manner to a common environment, but the very con- stant and uniform conditions of our fresh waters throughout the world have resulted in the greatest similarity of forms, widely dispersed over the earth. The insect life of the water ^ords an especially interesting study since it represents a secondary adaptation. It is believed that insects were all terrestrial in the beginning, but that some have invaded the waters and acquired those structural pecul- iarities that enable them to cope successfully with conditions in a medium some 775 times as heavy as air. An examination of the insect fauna of the water will indicate that it is a heterogeneous group, gathered together from the various orders of insects, and illustrating different stages of adaptation. As Bastin has stated "insects are essentially creatures of the earth and air," but many species have adopted an aquatic life, some to spend only their immature stages in the water, others to linger there throughout most of their days, quitting it only to extend the foraging grounds through flight. To this latter group belong the water bugs. It is the purpose of this chapter to indicate some of the structural contrivances possessed by these insects, and the manner in which they are used. The chief modifications have taken place along the lines of locomotion, prehension, and respiration, and under these three heads the question will be discussed. In considering these various questions it is natural to treat the subject from the standpoint of degree of adaptation. This (38) hungerford: aquatic hemiptera. 39 will be done, beginning with those being the least adapted, and ending with those with most perfect adaptation to an aquatic life. LOCOMOTION. In the matter of locomotion of those forms that live upon the waters and shores adjacent, we find all gradations from those that venture but timidly upon the water to those that boldly set forth upon the deep. In fact, there are some that fre- quent the banks and are found upon the waters only by acci- dent. Such are the Saldidse, Ochteridse and Gelastocoridae. The first family is so called because of the jumping propen- sities of its members. As a matter of fact, the members of all three families jump. The first are extremely agile, running and jumping with alac- rity, using the wings in tremendously quick flights of a few inches. The last named run or go bumping along like toads. Unlike the well-known Saltatores among the Orthoptera, the hind femora are not notably enlarged. The hind coxse, how- ever, in some at least, are considerably thickened. The spines of the hind tibia, instead of being arranged on the caudal side, as in grasshoppers and Jassids, are arranged on the opposite and inner side. The middle tibia possesses a few spines, the hind tibia and tarsus many. When the live insect is studied in respect to its locomotion, the position of the limbs makes their armament very clear. These insects rest with femora of hind limbs at right angles to the body, and the front side of the long tibia often in contact with the ground. The tarsal claws are terminal and the fore and middle tibiae of the Saldidse bear on their inner distal end tibial combs. An examination of the members of these three families indi- cates a superficial resemblance, with the Ochterid bridging the gap between the Gelastocoridse and the Saldidse. The Hebridse observed by the writer, though occupying the same territory as the Saldids, are equipped more like the Microvelias. The body is covered with a short pile. The limbs, fore and middle, possess tibial combs. The claws are, however, terminal, and in this respect distinguish them from the Microvelias. The above shore bugs are followed by a mixed lot that extend their range to the floating vegetation. Here belong the Micro- velias, Mesovelias and Hydrometras. All of these have the \ 40 THE UNIVERSITY SCIENCE BULLETIN. limbs covered with a close pile, and the last two have the claws still terminal upon the tarsi. This series leads to the Gerrids and Veliids, which habitually traverse the open water. With these the bodies are set with a covering of short close pile and the limbs are long, distributing the weight over a greater sur- face. The claws are small and subapical, thus affording less likelihood of the limb piercing the surface film. Bueno has figured the remarkable modification of the foot of the middle leg of Rhagavelia obesa, and copies of his drawings will be found on plate'Viii; figure 6. The last tarsal segment is deeply cleft and furnished with a series of ciliated hairs capable of spreading into a fan-like structure. According to Bueno, this fan-like structure spreading from beneath the cleft in the tar- sus projects into the water and aids the insect in rowing. Rhagovelia is found in the swiftest part of the streams, and this unique device is a material aid to its locomotion. This bug has the reputation of diving and swimming under water. This habit, however, does not indicate that in any such a way the true aquatics came to extend their range. More probably did it come about by the occasional submergence of some Gelastocorid-like form frequenting the margins of streams and tidal marshes, and clinging tenaciously to its haunts, though occasionally and even periodically submerged. Masen, in Entomologist's Monthly Magazine, vol. XXV, p. 236, cites two species of Saldids that move about from plant to plant under water. Thus we come to the true aquatics. Mr. Bueno gives some observations on the methods employed by the various forms in a paper entitled ''Ways of Progression in Water-bugs." It will be apparent to any who examine the true aquatic Heteroptera that, among them, the Naucorids represent the latest addition to the water fauna. The hind limbs are spiny and angular, like the Gelastocorids, and possess few, if any, hairs that make for efiiciency in swimming. The middle tibiae possess tibial combs like the littoral forms. Unlike their more specialized relatives, they walk very well upon the land. The Nepidse also present little modification of the limbs for traversing the water, due no doubt to their "lying in wait" habits. The Belostomatidae have their second and third pair of limbs flattened and fringed with hairs. Bueno says that "Lethocerus amer-icanus when hard pressed and with a free hungerford: aquatic hemiptera. 41 field, stretches out its raptorial front legs before it, and gives ' long strong, propulsive strokes with the other tw^o pairs, moved sychronously. When not pressed they paddle slowly, alternating the middle and hind legs." Of the Notonectidse the little Plea, living midst the tangles of pond vegetation, makes but short excursions from stem to stem by "short little clipping strokes" of its limbs. These limbs on superficial examination appear but slightly fringed with hair, but careful study will reveal them about as delin- eated in figure 2, plate XXH. All their limbs end in strong claws. The other genera, Notonecta and Buenoa, have hind limbs obviously set apart for rowing. They are flattened and bordered with close rows of long hairs. These collapse on the return, spreading with the pressure of the pulling stroke. The tarsal claws of the hind limb are so small that they are scarcely ' discernible amidst the fringe of swimming hairs. These rear limbs, the height of efficiency for propulsion in the water, are suffered to be dragged upon the land, the other limbs already ungainly in their modification for prehension, afford- ing it an awkward means of getting about. The greatest diversity of limb structure is undoubtedly possessed by the Corixids. The middle limbs are long, lean structures, ending in long, slightly incurved claws. These are employed only in grappling the irregularities of the bottom of the pool, thus holding their owner to their accustomed foraging grounds. The hind limbs fashioned like those of the back-swimmers,' are even quicker in their execution. In- deed no water insect has greater agility and darting propensi- ties than has the water boatmen. prehension. Kirkaldy once stated that "all of the water forms (with the possible exception of Corixidse) are raptorial." He later modi- fied this to except the Hydrometra, the front legs of which are not thickened, stating that "although doubtless they are em- ployed for holding the food during feeding, they cannot be said to be noticeably modified for raptorial purposes." In fact, the writer has found that Hydrometra habitually spears its prey from beneath the surface film, and retains it by "\ means of the tremendously long, flexible mandibular stylets which are strongly and retrorsely barbed at their tip. (See plate XXIX, fig. 3.) / r 42 THE UNIVERSITY SCIENCE BULLETIN. Rheumatobates, too, dips below for ostrocods, etc., which it scoops out of the water and holds aloft upon the upturned tip of the beak while the body of the little victim is being de- pleted of its nutritive material. Microvelia and Mesovelia depend upon their stylets also for holding prey, and the fore limbs are very slightly thickened. The Gerris, Velia and Trepobates have thickened femora and use the fore legs in holding prey. The Saldidae and Ochteridse have the front legs modified slightly. In some of the Saldids the fore tibia is armed with a few spines so directed as to be of slight service in grasping. The Gelastocorids have the fore limbs well modi- fied into grasping organs. The femora are thickened and margined with stout spurs. The tarsal claws are heavy and fit against the coxae firmly. (See pi. IX, fig. 1.) The Naucorid carries this plan still farther, the femora being greatly enlarged with the tibia and tarsus fitting snugly against it when flexed. In the Belostomatids the same arrange- ment is found, though not to the same extent. In the genus Lethocerus the femora are grooved for the reception of the tibiae. The Notonectids furnish an illustration of still further use of the limbs in the manipulation of prey. These insects do not cling to supports, but poise back downward in the water, thus freeing not only the front pair, but the middle legs as well, for service in retaining captured victims. In the genus Notonecta the femora of both fore and middle legs are large and armed with short spurs and spines. The members of this group are fierce predators and attack other insects often larger than they. (See pi. XX, fig. 8.) On the other hand, it is interesting to examine the limbs of the Buenoa modified for retaining prey — but very different kind of prey. These insects dart, poise and swim submerged, gathering in the Entomostraca by the half dozen, and retaining them impris- oned in a curious crib formed by the long, spiny armature of the flexed limbs. (See pi. XXIV, fig. 4.) Here the femora are not greatly thickened, but long and fashioned with a series of projections that make for efficiency in preventing the escape of small organisms. Notonectse nymphs feed on ostracods, etc., but seldom retain more than two at one time, and are not in the same class with Buenoa when it comes to hungerford: aquatic hemiptera. 43 getting the larger plankton of the pond upon which these latter largely feed. The predatory equipment of all of the above is perfectly obvious when you study it, but there is one large family of water bugs whose external equipment is strikingly peculiar and whose front legs, if used for catching and holding prey, have developed along a line quite remote from the usual form. This family is the Corixidae. The tarsus of the front leg is flattened, spoon-shaped, and fringed with long hairs. The inner surface of this pala is set with short processes, as seen in the figure (PI. XXIX, fig. 4) . Equipped in this fashion they make admirable scoops for gathering in the flocculent ooze upon which these insects feed. The feeding habits of these insects are elsewhere described in this thesis, and also in a paper that appeared in the Journal of the New York Entomo- logical Society. RESPIRATION. The respiration of those that tread or row upon the surface is like any terrestrial Heteroptera, and so our consideration can pass directly to the submerged fauna. On this subject there has been much speculation and some morphological study. The writer has not, as yet, had the time to review the question ex- haustively first hand. To arrive at the actual truth it will be necessary to study the structural equipment of each type, and with this foundation, experiment with living material. Of all who have written on the subject, only three have in fact at- tacked the problem correctly. These are Brocher, Hoppe and Ege. Brocher's work covers a wide field. Hoppe devoted an en- tire thesia to "Atmung von Notonecta glauca." His results do not agree with Brocher's, and thus the writer does not care to become a third party to the discussions until he has satisfied himself completely. The old idea was that insects carried a store of air below with them. Brocher, however, after remov- ing the guard hairs and modifying the air reservoir equipment in various ways, concludes that most of the air enveloping a submerged insect is expired air! After dedicating a whole series of papers to the records of the prosecution of this phase of the biology of aquatic insects one must consider very ser- iously his conclusions. The most recent paper on the subject is by Bueno, and appeared in the Annals of Entomological Society of America for December, 1916. Unfortunately this writer 44 THE UNIVERSITY SCIENCE BULLETIN. appended no bibliography and gave no hint of an acquaintance with the significant results of the recent European workers. His classification of respiratory types, however, is fairly stated if his interpretation of function be ignored. I. Dorsal reservoir: Corixids, Belostomatidse and Naucoridse. II. Abdominal channel: Notonectidse. III. Tube type: Nepidae. The Corixidse make contact with the air by the thorax, while the Naucoridse and Belostomatidse connect with the tip of the abdomen, as do the Notonectidse and Nepidse. The last named family have prolongations of the eighth abdominal segment, which afford a connection between the air and the spirac- ular openings, enabling these insects to remain at some dis- tance below the surface. In matters of meeting the problem of air supply the Co- rixidse, though less profoundly modified as to structure than the Nepids, are nevertheless the most independent in their be- havior of all the water bugs. The problem of aquatic respira- tion then is a complex one, and involves further study. There is yet another phase of hydrobiology that should be mentioned in connection with this chapter. It is. the mastery of the physical properties of the water relating to the surface film. Brocher has given us a splendid paper on the funda- mentals of this question, to which the reader is referred. He shows the clever devices that enable insects to walk upon the water, to rise out of the water, to break the surface film from below in making contact with a vital supply of free air, as well as to enter the water from above. It is interesting to watch a Notonectid just alighted, upon the water maneuver to submerge. Encased in nonwettable ma- terial, the body is buoyed up, and to submerge, the tip of the hind limb, which is wettable and attracts the surface film, is dipped into the water before the head and the film drawn thus over the back, covering the bug and placing him below. In the light of Brocher's work, there are many interesting experi- ments that suggest themselves concerning the manner in which the water bugs have met and solved the problems of their elected environment. Notes on the Semiaquatic Hemiptera. Under this section of the paper, and the next one on page 141, each family is treated under two heads: "A. Taxonomy of the Family" and "B. Biology of the Family." Under the first head is given the family characteristics fol- lowed, perhaps, by a brief historical note, then by a key to the genera. A brief characterization of the genus is given and each genus is provided with a key to its species where possible. Specific descriptions are given for most of the in- sects listed in Van Duzee's Catalog. Sometimes they have been shortened a trifle if the same information is presented in the synoptic key preceding. In one family comparative notes have been used and in two families undergoing revision (one of them by the writer), the description of species is omitted for the most part. It is hoped that this taxonomic matter may be found valu- able to the general student. The special student, as a matter of course, will go to the sources for his information. Under the second head, the "Biology of the Family," are given some general notes which relate to the family as a whole. This is followed by a treatment of the species of each genus. Under each species the notes are arranged in a general way as follows: Habitat, hibernation, oviposition, incubation, hatching, behavior of newly hatched, number of instars, ma- turity, fecundity, longevity, food habits, description of stages, and then a brief summary. The field of investigation in the realm of the biology of the water bugs is full of intensely interesting and promising problems on every hand. The notes which follow give us some idea of what has been discovered and what yet remains unknown. Family GELASTOCORID^ Kirk 1897. A. Taxonomy of Gelastocorid^. Family Characteristics. More or less squat, toad-shaped bugs, to be found upon the moist sand or mud bordering streams or marshes. The eyes are very protuberant and the entire body often has a mottled, rough, warty appearance. The antennae are four segmented, shorter than the head, and concealed beneath the eyes. Ocelli are present.* The * Absent in Nerthra. (45) 46 THE UNIVERSITY SCIENCE BULLETIN. rostrum is short, stout and four segmented. The fore legs are strongly raptorial. The limbs are more or less spinous. The fore and middle tarsi are one segmented, and the hind tarsi two segmented. (Under a lens Gelastocoris appears to have two segments in middle tarsus, one a very short one, and three in the hind tarsus, the basal one a short one. Cleared and mounted limbs show the long segments to be attached to the tibiae.) Three genera are present in this country. Gelastocoris Kirk., Mononyx Lap. and Nerthra Say. The first enbraces three species, each of the lat- ter, one, a total of five species for America north of Mexico. Histoncal Review. Most of us have learned to know these bugs under the name Galgulidse, though they have been given by turns the names Mononychidse and Nerthridss. KEY TO GENERA. A. Fore wings free. B. Fore tarsus with two claws. Gelastocoris, (Galgulus) BB. Fore tarsus with a single claw. Mononyx. AA. Fore wings fused together on the back. Nerthra. Genus GELASTOCORIS Kirk. Variously marked, often mottled, exceedingly variable bugs of a broad flat appearance. The eyes are very protuberant and the antennae con- cealed beneath them; have the third segment very short and small, and "completely connate with the fourth." All the tarsi end in two strong claws. In ventral view the terminal abdominal segments of the male are seen to be asymmetrical. (See pi. IX.) In the female the 6th ventral segment is more or less convex along the middle. In 1901 Champion said that Montandon's monograph of this genus would appear shortly. In 1905 Bueno wrote that the only way to determine the species was by comparing the notes given by Champion. The writer has not yet found Montandon's monograph. The key to the three species is made from Champion's notes. Bueno has said that he is aware of several undescribed species. KEY TO GELASTOCORIS A. Lateral angles of pronotum rounded, moderately dilated and finely crenate. Pronotum slightly constricted. G. oculatus. AA. Lateral angles of pronotum acute. B. Lateral angles of the pronotum transverse or subtransverse along their anterior edge, distinctly crenate in front and be- hind. Spots on elytra well marked, often more or less ocel- lated. G. variegatns. BB. Lateral angles of the pronotum oblique in front and less coarsely crenate. General coloration more obscure than in species above. G. vicinus. hungerford: aquatic hemiptera. 47 G. Oeulatus Fabr. 1798. Fabricius, Ent. Syst. Suppl. p. 525. G. oc^ilatus is the only one recorded as general in distribution. The others are neotropical. This widely distributed species has been taken in Kansas, Oklahoma, Colorado, Arizona, Minnesota, Illinois, Michigan, Ohio, North Carolina, Florida, Georgia, Carolina, District of Columbia, Maryland, Pennsylvania, New Jersey and New York. The original de- scription of this species is very short and inadequate. Uhler says: Our Galgidus oculatus is a variously tinted chunk of insect entity, thick in front, horizontal, and gradually thinning towards the bluntly curved posterior end of the abdomen. The form thus resembles an Indian hoe or stone skindresser. The sides of the prothorax are expanded into thin, bent lobes, before which the margin is deeply sinuated, and then rises into the smaller, hollowed lobes which fit against the eyes. These lobes are ivory white beneath, and next to them the pleural depression is covered by fine, dense, pale granules on a dark spot. The upper surface is mud-brown of any shade, or it is red if the creature lives in a soil charged vvdth oxide of iron, or blackish brown in carbonaceous mud, or clear light brown if developed in clean, sandy loam, or flecked with silvery white on a mottled and variegated more or less olive greenish ground, when its birthplace and home are in the micaceous mixed soil. Almost the entire upper surface is closely set with fine raised granules, which give it a velvety appearance in some lights. Occasionally it frequents places where green slime accumulates between the stones near the bed of a brook, and then it is apt to be covered, and even permanently pene- trated by the bright green color of the algse. The legs are pale yellow, banded with browTi; the stout, compressed fore thighs are generally brown, interrupted by short, yellowish, transverse marks, the underside armed with marginal, close set, piceous, short teeth, separated by a longitudinal groove into which the spinous, bent, banded fore tibiae fit. The latter are also armed with a bunch of long spines a little way from the base, and between the others there are numerous more slender, shorter ones, which are continued upon the tarsi. The apical tarsal joint is also finished by a pair of long curved nails. The other femora and shanks are likewise banded with pale brown, and have a pair of long piceous curved nails." G. variegatus Guer. 1844. Gueriii. Icon. Ins. p. 352. This well-named species has a more definite or distinct pattern than the others. Champion says it is the most beautiful of the genus. "The pronotum is subparallel at the sides in front, the lateral angles are foliaceous, very distinctly crenate in front and behind, and transverse or subtransverse along their anterior edge." Taken in Texas, California, New Mexico. G. vicinus Champ. 1901. Champion, Biol. Centr. Am. Heter. II, p. 349. It would appear that Montandon had named this in his notes and sent some of the bugs to Champion for examination. Champion says: "It is very like G. variegatus but has the foliaceous lateral angles of the pro- notum, more oblique in front (instead of subtransverse), and less coarsely crenate. The pronotum is strongly constricted at the sides behind the anterior angles, the margins being subparallel in front. The general coloration is usually more obscure than in G. variegatus." Neotropical in distribution. 48 THE UNIVERSITY SCIENCE BULLETIN. Genus MONONYX Lap. In these bugs the body is more quadrangular than in Gelastocoris. The thorax being fully as broad as the abdomen. The adults have one strong claw on fore tarsus instead of two as in GelastocoHs. The an- tennae are 4 segmented, the third segment being narrow, "barely one-third the length of the fourth and almost connate with it." Champion. Mononyx fuscipes Guer. 1843. Guerin Rev. Zool. for 1843. This neotropical insect has been recorded for California. This species of Mononyx has the fore femur widest toward the base. The last segment in the male is small and placed considerably to the left of the longitudinal axis of the body, and the preceding ventral segment is foveate on the right side near the margin. In the female the two triangular pieces forming the last segment are broader than long, and the sixth is not very deeply emarginate. Genus NERTHRA Say. Shape suboval, depressed; head short and broad; scutellum small; hemelytra entirely coriaceous and linearly roughened in prominent points, soldered together along a straight suture indicated by a groove. Rostrum small. Anterior femora basally incrassate; tarsal claws single. Abdo- men rounded. Male genital segments laterally deflected. Nerthra stygica Say 1832. Say Heter N. Harm, p. 37. Bueno, Ohio Nat. Vol. V, p. 287. "Moderate in size, suboval, depressed; head short and broad with four tubercles in the middle, the outer two less elevated than the middle two; triangular in front and reflexed. Eyes reniform, not very prominent. Ocelli absent. Rostrum short, small and so hidden under the head as to be hardly visible (joints not counted for this reason). Prothorax, sides subparallel, curvedly converging in the cephalic third; base slightly sinuate; laterally flattened; apex nearly straight except at the eyes; disk much elevated and roughened. Scutellum triangular, sides sinuated, much roughened. Hemelytra slightly flattened and dilated at the humeral angles and gently curvedly, sloping to the rounded extremity; entirely coriaceous and linearly roughened in acute elevations along the lines of the sutures; soldered into one piece along a straight sulcate suture ex- tending from the caudal angle of the scutellum to the tip of the hemely- tra; apparently soldered to the scutellum as well; not entirely covering the abdomen, the connexival segments being moderately visible beyond the costal margin ; extending beyond the end of the abdomen. First pair of legs raptorial. Anterior femorje incrassate, flattened anteriorly and coming to a point; coarsely granulate; tarsal claws single. Intermediate and posterior pedes cursorial; femorse normal with a row of blunt teeth; tibiae with two rows of stout spines with a sulcus between; tarsi one- jointed in intermediate pedes and provided with double claws (tarsi of posteriors lost in the specimen before me). Mesosternal tubercle rather acute and laterally somewhat flattened, terminated by bristles. Male abdominal segments much compressed in the middle to give room for the large and prominent genital segments which are deflected toward the right. Abdomen rounded, with an entire margin. "Color, blackish-brown above, except the flattened prothoracic and hemelytral lobes which are yellowish and translucent. Underside of the hungerford: aquatic hemiptera. 49 abdomen more or less black. First pair of legs entirely black; second and third more or less spotted with lighter color. "Dimensions: Insect — Long., 7.4 mm; lat., 5.3 mm. Head including eyes — Long., .6 mm; lat,, 3.4 mm. Prothorax — Long., 2.4 mm; lat., 5 mm. _ Abdomen — Long., 4.4 mm; lat., 5.3 mm. "Redescribed from a single specimen in the collection of Mrs. Annie Trumbull Slosson, who took it in Florida. "The much roughened upper surface together with the entirely coriace- ous hemelytra fused into one will at once distinguish this species from all the other Mononychinje. "The preceding descriptions will doubtless be found lacking in many respects, but dissection being necessary to determine certain anatomical features and characters, such, for instance, as the antennae, the posses- sion of only one specimen, and that not my own, has made it impossible to supply what is missing." — Bueno. He adds: "As Say's description is not accessible to all, I give it hereafter taking it from the Le Conte edition": "N. stygica. — Black, front quadrilineate. "Inhabits Georgia. "Body oval, brown-black, rather rough; head crenate on the front so as to form four denticulations; eyes rounded, rather prominent; thorax not emarginate before, with a slightly depressed margin behind; anterior thighs dilated triangular; hemelytra with oblique lines; they appear united at the suture. "Length three-tenths of an inch. "I have but one mutilated specimen which was sent to me by Mr. Oemler. If I am not deceived by this specimen, the species is apterous and the hemelytra are united by a rectilinear suture, which will require the formation of a separate genus which may be named Nerthra." This rare insect has been taken in Florida and Georgia. B. Biology of the Gelastocorid^. General Notes. These strange bugs are to be found about the moist grounds bordering streams or other water bodies. Some of them dig burrows into the sand or mud. They feed upon other insects, pouncing upon them with a sudden jump. Their general shape and coloring ren- der them difficult to discern in their native haunts. Genus GELASTOCORIS Kirk. Biology of G. bculatus. Habitat. Uhler has told us how the color varieties harmonize with the bug's surroundings. (See description above.) We have found those on mud flats slate color, and those on the river sands mottled and pebbled like their dwelling place. It is found amongst the "stones and low banks of brooks and streams" or upon the barren sands of the river flats. These bugs are gregarious and peculiarly local in distribution. A colony may be found in one spot along a given stretch of the stream and nowhere else. Hibernation. Bueno took these bugs in their second instar at Long Island in late September.* He found no adults, from which he inferred that they hibernate as nymphs.f Mating. The writer is not aware of any observation on this point. The sexual differences due to the asymmetry of the male was noted as : » * Three Days in the Pines of Yaphank., Can. Ent., July, 1912. t Our Kansas^ forms winter as adults, burying themselves in the sand. 4 — Sci. r.iil. — 1669. 50 THE UNIVERSITY SCIENCE BULLETIN. long ago as Brulle's time at least, (1836). Figures of this difference are shown on plate IX. Oviposition. It has been stated that the eggs are deposited in the ground, but the writer has not been able, so far, to verify this point. The ovipositor parts bear strong, dull tipped spines or pegs, that might well serve the purpose of pushing aside the sand grains. A drawing of these parts is shown on plate IX. Number of Instars. From the collection of nymphs there are certainly five instars. Uhler says there are two broods in the east. The second one coming in August. Food Habits. Again we get some observations from Uhler who writes most vividly of bug behavior : "They may often be seen in the month of May walking about between the stones on the low banks of brooks and streams, where Tettix and Batrachidea abound, watching an opportunity to seize one of these insects, and when the favorable moment arrives, leaping suddenly upon one of them, clasping it with tight embrace be- tween the front femora and tibiae, and there sucking out all its vital juices." Professor Thomas reported its capture of Xya termiiialis in the same way. Uhler says it uses little discrimination, seizing the larvse of ground beetles, and almost any other kind of insect which comes its way. The writer submits a photograph herewith (plate V) to indicate the greediness of these bugs, and the fact that their food source was close at hand. The lace bugs in this case were reared on the vegetation near by. Some bugs were taken with a half dozen lace bugs held in one embrace. Another one had some small Capsids. Behavior The writer found these in greatest abundance near Russell Springs, in Logan county, and from the river a few miles north of Gn^el©*^, "' in Wallace county, Kansas. Mr. Alexander brought in splendid series from Pawnee county, Kansas. These insects jump quickly when dis- turbed, and squat flat upon the sand where the mottling of their backs merges into their surroundings, rendering them well nigh indiscernible. The position of their hind limbs and the location of the spines of the tibia, where they will best serve their purpose, is an interesting adapta- tion to use. See photo., plate IV. DESCRIPTION OF STAGES. The Egg. Up to date the writer has not been able to follow the life history of the toad bug. Mr. C. P. Alexander brought in from Larned, Kansas, a considerable series of adults and last instar nymphs. From this material the writer has figured the ovipositor of the female, and the ovum. One female contained 10 ova. The mature eg^ meets the following descrip- tion. Size. Length, 1.25 mm; diameter, 91 mm. Shape Broadly oval, as shown on plate IX. The surface is roughly granular, and marked into irregular hexagonal areas by thickened ridges of the chorion. HUNGERFORD: AQUATIC HEMIPTERA. 51 The Nymph. In the last nymphal instar the wing- pads reach to the base of the abdomen. The lateral margins of the prothorax are flattened but not "buckled" or constricted as in adult. The hind tarsi are single segmented. Ocelli are present! In Mononyx fuscipes, Champion says the ocelli are absent in the nymph. This is the usual case. Genus MONONYX Guer. So little is recorded in regard to the biology of the species that some one should rear it. It is predatory, as was long ago recorded. Champion says that the adult has only one claw on its fore tarsi, the nymph of M. fuscipes has two long' claws. The segments of the inter- mediate and hind tarsi are fused into one, and the third and fourth an- tennal joints are connate. The ocelli are absent. Habitat. "These insects live in muddy places on the banks of ponds and sti'eams and are usually coated with an earthy incrustation, which cannot be easily removed." Family OCHTERID^ Kirk. 1906. A. Taxonomy of the Ochterid^. Family Characteristics. Shore bugs with characters intermediate be- tween those of Saldidm and those of Gelastocoridae. The general appear- ance is also intermediate, resembling some of the Saldids, perhaps more than the toad bugs. The antennse are four segmented, shorter than the head, but exposed. The eyes are prominent, two ocelli present. Fore femora slightly if at all fitted for grasping. Rostrum is long, like that of the Saldids, reaching the hind coxse. The first and second segments are short, third, very long and slender. Tarsi are given by Parshley as two-segmented behind, with a question mark after the statement "front and intermediate tarsi one-segmented." We have but two specimens in the Snow collections at University of Kansas. The middle tarsi appear two segmented under binocular. Professor Barber's drawing of his Ochterus haiiski shows three segments in hind tarsi and two in each of the others. Historical Review. There is but one genus in the family. Ochterus Latr. 1807. He suggested the name Pelogonus for this genus two years later because he believed Ochterus was preoccupied. It is under the name Pelogonus that Uhler mentions these insects. The genus is sufficiently characterized by the family description. A more nearly complete de- scription can be found in Amyot & Serville, page 407. KEY TO SPECIES OF OCHTERUS. (After Barber.) A. Clavus entirely yellow. O. flaviclavus Barber. AA. Clavus concolorous. B. Entire lateral pronotal margins broadly pale. O. hanksi Barber. BB. Lateral pronotal margins, with only a pale spot anteriorly. O. americanus Uhl. 52 THE UNIVERSITY SCIENCE BULLETIN. O. flaviclavus Barber 1913. Can. Ent. XIV, p. 215. "Brownish-black. Very much the appearance of O. ameHcanus, to which it is closely related, having the usual carinate and rugulose face. However, somewhat smaller than that species with the clavus entirely yellow. The pronotum with the lateral margins gently rounded, more converging anteriorly, the anterior margin being narrower than the width across the eyes; the anterior angle of the pronotum sharply rounded and not projecting anteriorly as in ame^'icanus ; the expanded part of lateral margins narrower, with a small yellowish spot just posterior to the anterior angle; the humeral angle almost rectangular, projecting but a trifle beyond margin of corium. Extreme edge of corium very narrowly pale, but the usual pale marginal spots are lacking. Surface vdth the usual pearl grey spots. Beneath, with the sternum slate grey; the acetabula, posterior and lateral flange of the presternum, elytral flange anteriorly, posterior margin of metasternum, legs and venter, pale; legs lightly infuscated. Presternum, mesosternum, externally, and metas- ternum before the posterior angle, distinctly punctate. "Length, ZV2 mm.; width of pronotum, about 2 mm. "Described from a single male in the collection of Mrs. Annie Trum- bull Slosson, taken by her at Ormund, Florida." O. banksi Barber 1913. Can. Ent. XIV, p. 214. "Broad ovate, brownish black. The head, behind the vertex, opaque, from there anteriorly, shining and obliquely, finely rugulose and tri- carinate; one carina next each eye and a median one, continuous from vertex to apex; transversely sulcate midway between ocelli and base of head. Pronotum vdth anterior margin almost truncated, with the an- terior angles next the eyes rounded and not projecting forward or out- wardly beyond the exterior margin of the eyes; entire lateral margins gently rounding posteriorly; humeral angle rounded, not very prominent; lateral margins broadly expanded, pale; this mark broadest about the middle, more abruptly rounded anteriorly, and tapering posteriorly to occupy the entire margin; the remainder of the surface browmish black, slevated and transversely, but not very deeply, sulcate a very little behind the middle; posterior lobe, middle and anterior part of first lobe more coarsely punctate, the latter with two or three transverse weak fur- rows. Scutellum almost equilateral, rather coarsely punctate and trans- versely furrowed; anteriorly with a transverse elevated ridge, behind which it is depressed. Corium not demarked from membrane, broadest across the middle, with lateral margin gently rounded to just beyond middle, where it more abruptly rounds off" to the rather narrow apical part of membrane; the external margins either broadly pale throughout or in part suffused with fuscous and reflexed, without the usual series of pale marginal spots which occur in O. aniericanus. Clavus and corium, anteriorly, with coarse scattered punctures. Nervures of the membrane indistinct. General surface with indications of the customary bluish grey markings, unless denuded, when the whole upper surface is smooth and shining. Beneath on sternum and venter paler, with rostrum, acetabulae, coxae, legs and external angle of metathorax pale yellow. Prosternum rather coarsely punctate. "Length, 4 mm. Width of pronotum, 2 mm. "Described from three males and one female collected by Mr. Nathan Banks of Glencarlyn, Virginia, in June. Judging from the meagre descriptions and indiff'erent illustrations at hand, I am led to the opinion that this species is most nearly related to O marginatus Latr., of Europe. But having no specimens of that species for comparison, I am, at this HUNGERFORD: AQUATIC HEMIPTERA. 53 time, unable to settle the point. O. banksi can readily be separated from americamis by its difference in color, markings, and the character of the pronotum. Apex of membrane is more narrow than in americanus." O. americanus Uhl. 1876. Bui. U. S. Geol. Geog. Surv. 1, p. 335. "Broadly oval, slaty-blackish, opaque, the pronotum a little narrower than the abdomen. Head polished, minutely punctured in part, invested with very sparse prostrate pubescence, which is more dense beneath; rostrum reaching the end of the second ventral segment, blackish-piceous on the swelled base, the rem.ainder pale ruf o-testaceous ; antennae pale piceous; face obsoletely carinate, each side with a series of oblique wrinkles, its anterior and lateral boundaries carinated. Pronotum trans- verse, velvety blackish, with a few short wavy lines and some dots of bluish lead-color, and remotely golden pubescent; the lateral margins slightly oblique, only a little narrowing anteriorly, and rounding against the anterior angles, which are distinct and almost acute; touching the margin a little way back, each side, is a small triangular yellow spot; posterior angles subrectangular; the posterior margin waved each side of the center, where it is also a little yellowish. Pectoral surface dull black, with very sparse sericeous scales exteriorly; the spots of the dorsal margin equally visible beneath; sternal margins piceous. Legs dull pale piceous-yellow. Hemelytra broad, widening posteriorly, velvety black, pubescent, sprinkled with golden pubescence, spotted and dotted with bluish lead-color; the costal margin yellow, and with five small yellow spots; membrane bluish lead-color, with the nervures black. Venter piceous black, densely, minutely sericeous pubescent, the edges of the segments and the tip of the last one a little reddish-piceous. The con- nexivum is unspotted, and the surface of the tergum black, polished, with rufo-piceous edges to the segments. "Length, 5 millimeters. Width of pronotum, 2i/2 millimeters. Width across the hemelytra, scantily 3 millimeters." Has been found in Nebraska, Illinois, Texas, Arizona, Massachusetts, New York, New Jersey, Pennsylvania, Maryland, North Carolina and Florida. B. Biology of the Ochterid^. General Notes. These bugs are spritely fellows, dark in color, that live upon the shores. They are predatory in habit. Habitat. Uhler says of O. aTnericanus : "This is a gay, active little insect, which measures only one-fourth of an inch in length, and lives among the grass and weeds on the margins of brooks and ponds from Massachusetts to Texas. Hibernation. Dufour said that these insects appear in April. Thus they overwinter as adults. Practically nothing is known of their life history. Dufour describes the nymph of a species. But concerning the egg, number and length of the instars, etc, we have no data. Feeding Habits. Uhler says that the fore legs of O. americanus "are slender and fitted for running, not calculated for seizing and holding prey, as in Galgulus and Mononyx. The rostrum is, however, a dreadful instru- ment, sharp as the finest needle, extremely thick and stout at the base, and a deadly probe to a poor larva of horse-fly or other insect which lives next to the surface of the ground in situations near water." 54 THE UNIVERSITY SCIENCE BULLETIN. Family SALDID^ Amyot & Serville 1843. A. Taxonomy of Saldid^. In the treatment of the systematic part of this family the writer has been fortunate enough to secure the loan of the Hayden Geological Re- port of 1877 from the John Crear Library, of Chicago. This contains Uhler's monograph of the Saldidae and the descriptions of all but a dozen of those listed in Van Duzee's checklist. These latter have been gleaned from the various sources in which they appeared. Uhler stated at the time (1877) that only one genus was used but that good characters could be found for erecting others. Thus Reuter in his paper "Zur generischen Teilung der palaarktischen und nearktischen Acanthiaden" separates the family into 13 genera, eight of which are his own. This paper appeared in "Ofversigt af Finska Vetenskaps-Societeten Forhandlingar Bd. LIV, 1911-12, Afd. A. N. 012," which, by good chance, ' was found in the exchange library of the Kansas Science Bulletin. As the title indicates, the paper is in German, but the tables and descriptions are in Latin. The writer has essayed to adapt the tables to the genera recognized in Van Duzee's list and to render in English his generic de- scriptions in part: "Family SALDID^ (A. & S.) 1843. "Form oval or long-ovate. Eyes large, strongly exserted, inner mar- gin posteriorly emarginate or sometimes only subsinuate. Ocelli two, distinct or very rarely united into one. Rostrum three-segmented, first segment very short. Antennae much longer than the head, four-seg- mented, subfiliform or two terminal segments enlarged. Pronotum trape- zoidal, with the anterior side much the shorter, lateral margins oblique, with the edges recurved and the submargin depressed; the latero-pos- terior angles overlapping the base of the scutellum. Xyphus of the presternum short, triangular, the presternum short, projecting backward like a lid, over the base of the anterior coxae, the propleura with a roundish pit beyond the anterior angle of the presternum. Mesosternum grooved, with the coxae placed moderately close together. Metasternum deep-seated, the coxae in contact at the base. Hemelytra without cuneus. Membrane with looped nervules, forming a transverse series of four or five long areoles. Posterior coxae cardinated, broad. Posterior tro- chanters very long, acute, placed on the inner side of base of femora; the posterior femora and tibiae longer than the others. Anterior femora slightly thicker than the others. Tarsi three-segmented, first very short. Male genital segment with a dorsal apical opening, with two curved styles converging apically. Last ventral segment of female retrorse, usually produced, rounded, plate-like, covering the genital segments, apex rarely truncate and exposing the genital segments." — Uhler and Reuter. "The posterior legs are thrown very far back by reason of the very large and long coxae, and, together with the long femora and tibiae, give them a great facility in vaulting into the air. They use their wings in connection with this motion, and generally alight several feet from the point of departure. Their motion in running over the ground is often sinuous, while rapid, and their selective adherence to the spots which best agree with their combination of colors may well shield them from the pursuit of enemies." — Uhler. This family Saldidje is represented in America by eight genera and thirty-two species. Reuter recognizes two subfamilies which may be separated as follows: HUNGERFORD: AQUATIC HEMIPTERA. 55 KEY TO SUBFAMILIES. A. Vertex rather broad. Inner margin of eyes posteriorly emarginate. Saldinag. AA. Vertex narrow. Inner margin of eyes posteriorly subsinuate. Saldoidinse. Subfamily Saldino. Eyes with inner margin posteriorly emarginate. Vertex rather broad. Second segment of antennse distinctly longer than the third. Anterior part of pronotum marked by a large transverse oval callosity. This cal- losity often extending beyond the middle. Its disc usually marked by a median foveola. Posterior disc usually marked on both sides by a longitudinal impression reaching to the callosity. Lateral margins en- tirely carinated. KEY TO GENERA OF SALDINO. A. Pronotum, sides being more or less flattened, front callus never reach- ing to the lateral margins of the sides. Sulcus behind this destitute of punctures and longitudinal wrinkles. Most rarely of all marked with punctures, in this case apex of pronotum almost as wide as head with the eyes. B. Membrane marked with five entire areoles, last ventral seg- ment of female truncate. Pentacora. BB. Membrane marked with four or five areoles of which the sub- external is shorter than the rest, third and fifth more or less contiguous toward the apices. C. Apex of pronotum almost equal in width to the head, a little wider than this. Hemelytra densely and usually distinctly punctulate or subcoreaceous. Posterior tarsi with second and third segments subequal in length, body often wide, membrane usually with five areoles, of which the subexternal one is shortened. Chiloxanthus. CC. Apex of pronotum narrower than head, rarely as wide as this, in this case the hemelytra not punctate. Mem- brane always four-areolated. D. The membrane with its first area or inner base prolonged two-fifths or one-half beyond the base of next area. Hemelytra often punctate, always des- titute of sericeous patches. Embolium entirely black. Salda. DD. The membrane having its first area or inner base prolonged slightly or not more than a third of its length beyond the next area. E. Corium with two entirely distinct veins, inner one furcate toward apex, branches touching the suture of the membrane. First area of membrane or anterior apex usually touching, or nearly touching apex of second. Saldula. 56 THE UNIVERSITY SCIENCE BULLETIN. Key to Genera ok Saldino — Concluded: EE. At least the inner vein of the corium de- stroyed toward apex. First area or interior apex of membrane distinctly placed above the apex of the second, very rarely almost touch- ing this. In this case two veins of corium ob- solete. Hemelytra entirely or nearly opaque or sericeo-opaque. Micracanthia. AA. Apex of pronotum always distinctly narrower than the head with the eyes. Apical stricture distinct. Callus strongly convex, termi- nated by anterior and posterior deep sulci. Marked with punctures and little longitudinal wrinkles. B. Toward apex of pronotum quite strongly narrowed, sides straight, callus by no means touching lateral margins, leaving a rather broad margin extended a little behind the middle. Hemelytra opaque, only the costal area of corium and em- bolium being shiny. Ocelli slightly distant. loscytus. BB. Toward apex of pronotum strongly narrowed, sides more or less sinuate. Callus occupying all or nearly all of the width of the pronotum, leaving only a narrow or very narrow mar- gin. Ocelli very little separated. Lampracanthia. Genus PENTACORA' Reuter 1912. "Body oblong. Eyes slightly converging anteriorly. Ocelli slightly distant or subcontiguous. Tip of rostrum reaching apex of intermediate coxae. Second segment of antennas as long as width of head, or distinctly longer. Pronotum toward the apex moderately narrow, broadly emargi- nate at base. Sides flattened, lateral margins toward apex strongly rounded or forming distinct angles. Callosity by no means touching lateral margins, transverse impression placed behind the middle of the disk, the scutellum, longer than broad, impressions far remote from base. Hemelytra often densely and usually distinctly punctulate. Interior vein of corium furcate toward tip, branches touching suture of the membrane. Membrane marked by five oblong areas, first or interior area moderately produced beyond the base of second. Apex almost attaining apex of second. Third segment of posterior tarsi a little shorter than second, or subequal to it in length. Last ventral segment of female slightly pro- duced, genital segment by no means totally hidden. Type Acanthia signoreti Guer. Three Nearctic species, signoreti Guer., ligatai Say, and hirta Say." Pentacora signoreti (Guerin) 1857. Salda sifjnoreti Guerin, La Sagra's His. Nat. de Il'Ile de Cuba, Hemipt., 401, pi. 13, fig. 10. Acanthia signoreiii Stal, num. Hemipt., Ill, 148, No. 1. "Oval, sand-yellow with black markings, or black with sand-yellow markings, all over minutely sericeous pubescent. Head more or less marked with black between the eyes and behind, omitting the amber ocelli and two spots on the vertex, or with only two small black spots on the vertex; gula with a broad black spot; the emarginated inner side of the eyes generally black. Antennae yellow or pale piceous, the basal joint black beneath and at base; second joint blackish or dusky beneath; third and fourth sometimes blackish beneath, the latter almost as short as the basal one, the third longer. Rostrum reaching to behind the middle coxae, piceous or black, with the basal joint pale. Face with a longitudinal groove, and the cranium with a few wrinkles and ridges. Pronotum wide, deeply concave behind, with the humeral angles drawn out obliquely into hungerford: aquatic hemiptera. 57 broad, flat lobes, with a little hump at the outer corner; surface finely pubescent, closely, finely, obsoletely punctate; with a dull black spot on the disk of the anterior lobe, which sometimes runs back narrower to the base, and on each humeral angle a black spot. Antepectus sand-yellow, but generally with the middle line of the sternum black; mesosternum, excepting its lateral lobes and posterior margin, black; metasternum also black. Legs sand-yellow, the coxje m^ore or less black, as also the apex of the tibiae, and a band on the tips of the second and third tarsal joints; nails generally testaceous. Scutellum black, minutely punctate, finely pubescent, arcuately impressed before the middle and with a slight elevated hump each side, usually carrying a yellow spot; the apex acute broadly yellow, or with two yellow, approximate spots, the lateral edges sometimes yellow. Corium sand-yellow, or whitish and yellow, minutely punctate and pubescent, marked with black or fuscous in very varying proportions, generally with a double black spot on the costal area before the middle, a similar spot behind the middle, and a smaller rounded one at tip; disk next the clavus and the clavus fuscous or blackish, the latter sometimes with a small yellow spot near the inner posterior angle, the former very often with a large yellow spot in the middle of the posterior margin, and often the margin itself yellow; membrane sand-yellow, some- times clouded with fuscous, and with a short transverse black band at base, the nervures piceous, long, and nearly straight. Venter pale yellow, finely pubescent, more or less blackish at base, and streaked on the disks of the segments each side, and sometimes with a row of black points a little way from the lateral margin ; the genital segments and ovipositor more or less blackish. The spots on the costal area are frequently want- ing, or have only traces present; occasionally the tip of the slender cuneus is black. Generally the whitish spots at the apex of the discoidal area of the corium are present and very conspicuous. "Length to tip of venter 5-6 millimeters; to tip of membrane 6-7% millimeters. Width of base of pronotum 2% -3 millimeters. "First obtained in Cuba; afterward in Sonora, Mexico; since then on the sea coasts of Massachusetts, North Carolina and Georgia. I have met with it in large numbers on the sea coast of Worcester county, in Maryland, in July and August. It lives on the pale sands not remote from the beach, and the darker varieties may be met with running briskly over the gray or blackish sandy mud, neglecting the dry spots, but often swarming upon the moist places. "The genital segment of the male has a long, curved, acutely tapering appendage, and two shorter and straighter approxim.ate ones in the middle, superiorly." — Uhler. In the matter of distribution. Van Duzee adds New Jersey, Florida, Texas and California. Parskley adds New Hampshire. Pentacora hirta (Say) 1832. Acanthia hirta Say, Heteropt. New Harmony, 34, No. 2. "Brownish, darker before. Body densely hairy, dull yellowish-brown or fuliginous; head a little darker at base; thorax blackish before the trans- verse line. Scutel blackish. Hemelytra conspicuously hairy, with dull yellowish spots, as well on the membrane as on the corium. Pectus a little varied, with the remaining inferior surface, including the feet, immaculate. "Length to tip of hemelytra under one-fourth of an inch. "This species may be recognized by its more obviously hairy vesture; its color is also paler than usual in this genus. Inhabits Indiana." — Uhler. To Indiana, Van Duzee adds Quebec, Connecticut, New York, New Jersey, Florida and Texas. 58 THE UNIVERSITY SCIENCE BULLETIN. Pentacora ligata (Say) 1832. Aoanthia ligata Say, Heteropt. New Harmony, 34, No. 1. "Form the same as in the Pentacora signoretii, black, a little shining. Head a little narrower, black, with a yellow arc on the arched base; the margins of the orbits of the eyes, the cheeks, tylus, and collum of the throat more or less yellowish; vertex with two impressed oblique lines converging before the ocelli, a short, longitudinal one outside of each ocellus, and a short, wide groove on the middle of the raised front; the front generally bounded beneath by a transverse yellow band. Rostrum reaching upon the intermediate coxae, slender, piceous, the basal joint yellow, with its apex black. Antennas piceous or black, the basal joint paler above, short and thick; the apical joint a little shorter than the third, but very much longer than the basal one. Pronotum trans- verse, moderately flat, with the anterior lobe, omitting the outer margin, very prominently convex, indented, and bounded by an impressed line; surface black, shining, exceedingly minutely punctate, very finely pubes- cent; the lateral margins white, abruptly recurved along their whole length, and a little concave; posterior margin deeply, concavely sinuated, with a yellow spot each side, and a smaller one in the protracted, ob- liquely truncated angles ; the extreme outer angle with a short tubercular ridge. Antepectus black, broadly margined all around with whitish, minutely punctate and finely pubescent; remaining pectoral divisions dull black, finely pubescent; margined behind and outside with white, and with extero-posterior lobes also white. Coxae black, terminated and margined with white; femora lineated, with black on the inside and outside, either throughout or in part; the knees and lines upon the tibije and their ends, the basal joint of tarsi, and the ends of the second and third joints also black; nails pale piceous. Scutellum black, very minutely punctate, finely pubescent; a short, linear, yellow spot on the margin, at the outer end of the transverse impression, and the acute tip with a more or less slender spot each side. Corium black, finely, closely punctate and pubescent; the costal margin, a longish double spot on the suture a little behind the base, a similar but larger spot on the middle, a third, either double or triple, near the apex, two or three smaller ones near and on the posterior margin, and one near the inner angle of the clavas yellow; the base of the costal margin is less expanded than in the preceding species; membrane blackish, with a transverse series of oblong, pale spots behind the base; the cuneus yellow, but black at base. Venter black, polished, very minutely punctate, remotely, finely pubescent, the segments margined behind and exteriorly with white. Male genital segment very closely set with long bristles, with still longer, very slender, strongly curved appendages, and with two short teeth on the middle superiorly. The other attachments are not disclosed in my specimens. Length to tip of venter, 4-5 mm.; to tip of membrane, 5% -6 mm. Width of base of pronotum, 2-3 mm. "A sprightly species, which inhabits dark rocks in the beds of running creeks and brooks in the metamorphic region of Maryland ; and of eastern Massachusetts, near Waltham and West Cambridge, from May till Octo- ber. It flies from rock to rock on such as are not covered by the water, and from its wariness and activity is quite difficult to capture. "Mr. Kennicott found specimens in Illinois; others have been sent to me from Ottawa, Canada, by Mr. Billings. Mr. Scudder collected it near Lake Winnipeg. Mr. Sanborn met with it on the Magalloway river in Maine, and on a brook near Andover, Mass. The Abbe Provancher sent me specimens from Port Neuf near Quebec, and Mr. Say's came from Indiana." — Uh lev. Van Duzee adds Maine, New York, North Carolina, Minnesota and Nebraska. hungerford: aquatic hemiptera. 59 Genus CHILOXANTHUS Reuter 1895. "Body wide. Gula of head rather short. Eyes anteriorly less con- vergent. Ocelli distinctly separated. Interocellar space about as wide as the ocellus, or a little wider. Rostrum reaching to apex of intermediate coxa or a trifle beyond. Pronotum toward apex slightly narrowed, be- tween angles of the apical margins subequal in width to the head. Sides flattened, lateral margins suddenly angulated before the apex, the callus by no means touching the margin. A transverse impression placed behind this, behind the middle of the disc; base of margin broadly emarginate. Interior vein of corium of hemelytra furcate toward apex; branches at- taining the suture of the membrane; internal area or first basis pro- duced before the next area, never more than one-third, rarely only one- quarter of its part; the apex by no means reaching the apex of the second. Last ventral segment of female truncate. Type Acanthia pilosa." Chiloxanthus stellata Curtis 1835. Acanthia stellnta Curtis, Ross's Second Voyage to the Arctic Regions, appendix Ixxv, Nov. 24. "Blackish sericeous; elytra with a pale spot at the center and several at the apex; legs ocherous. Black, clothed with very short shining hairs; thorax transverse, the edge beneath subocherous, as well as the center of the antepectus; scutellum rather large; elytra with the costa reflexed at base, a semitransparent spot at the base, another on the disk, and eight or nine arranged in a circle on the submembranous apex; margins of ab- dominal segments beneath ocherous, and forming a row of dots down each side; legs dirty ocher, somewhat freckled with piceous. "Length three lines. "The head is wanting to the only specimen I have seen ; it most re- sembles A zosterx Fabricius, but it is very distinct from my examples of that insect. As some of its larvae or pupae were found, it is probably not uncommon in the polar regions." — Uhler. Van Duzee specifies as localities: Arctic America; Pt. Barrow. Genus SALDA Fabricius 1803. "Body very broadly obovate or macropterous forms oblong ovate. Head subvertical, partly deflexed below and converging a little anteriorly, gula quite long. Ocelli subcontiguous. Rostrum reaching the middle of the posterior coxse or little more. Antennas quite slender, shortly pubescent, longer pilosity sparse. Second segment 2% or 3 times the length of the first. Pronotum toward the apex quite strongly narrowed. Apical mar- gin narrower than the head, sides straight or rotund. Callus quite large, attaining behind almost a quarter of the basal part. Basal margin broadly emarginate. Veins of the corium joined by an almost obsolete slender litle vein, interior vein furcate toward apex, branches reaching suture of membrane. Embolium entirely black. Membrane often ab- breviated. Alae usually abbreviated or lacking. Third segment of pos- terior tarsus subequal, length to second. Apex of last ventral segment of female elongated and rotund. Type Acanthia littoralis (L)." Salda littoralis (Linnaeus) 1758. Clmex littoralis Linnjeus, Fauna Suec, 246, No. 915; Sys. Nat., 481, No. 14. SoJda littoralis in Fieber, Europ. Hemipt., 147, No. 15. "Ovate, rather dull black, clothed above and beneath with closely appressed yellow hairs, the head with a few distant, prominent, black hairs. Head moderately long, the eyes very prominent, the face oblique, carrying a few long, erect, black bristles ; base of the head constituting a distinct neck, the throat concave ; tylus in the middle and the ends of the cheeks generally yellow, but sometimes totally black; front moderately flat, triangularly emarginate at the base of the tylus, the labrum broad, 60 THE UNIVERSITY SCIENCE BULLETIN. with the lateral edge sharp, and with a median ridge. Rostrum reach- ing almost to the middle of the posterior coxae (in one specimen, not ex- tending beyond the intermediate coxse) , piceous-black, paler or yellowish at tip. Antennae moderately long and slender, thickly clothed with fine, projecting, black hairs, a few of which are stouter; basal joint yellowish- brown above, dark at base, and beneath, with the basal two-thirds, blackish; second joint slender, dull yellowish, piceous at base and tip, a little shorter than the third and fourth united; third and fourth a little stouter, subfusiform, dusky black, subequal in length. Pronotum sub- trapezoidal, the posterior lobe transversely flat, the anterior lobe convex, reaching two-thirds of the length, smooth, bounded by a deeply impressed line each side and behind, its central fovea small ; sides flattened, the recurved edge bending abruptly downward before reaching the collum; posterior third of disk finely crenate-punctate. Scutellum finely crenate- punctate, finely rugulose behind, the depression large, somewhat incurved and well defined. Legs dull yellow; the femora with short, yellow hairs, the anterior ones blackish on the outside, and the middle and posterior ones with two rows of brown dots on each of the outer and inner sur- faces; tibije with short brown hairs and remote stouter black hairs; first and last joints of the tarsi blackish, the second joint and nails dull yellow. The tarsi are often soiled yellow, with blackish hairs, and with only traces of dusky on the ends of the first and last joints. Venter shining black, very minutely rugulose, clothed with fine sericeous, yellowish, prostrate pubescence, the posterior margins of the segments often pale piceous, and apex of the terminal segment yellow. "Hemeltyra minutely scabrous, golden sericeous, appressed pubescent; generally with an oblong yellow spot near the end of the clavus; corium marked on the disk with a longitudinal series of four long, yellow spots between the first and second nervules, and near the tip with one or two smaller spots placed more inwardly; costa.1 margin broadly arcuated, turned up, the submargin depressed, broader at base; membrane pale brownish or dirty yellow, sometimes short, and almost confined to the inner length of the corium, the cuneus black and coriaceous, inclosing the outer side of the membrane; the areoles with a series of black spots across the middle, more or less blackish at base and tip, and the nervules deep black. "Length to tip of venter, .5-6 mm.; to end of membrane, bVz-l mm. Width of base of pronotum, 2-2 1/^ mm. "Common in various parts of Europe, as well in the North as in the South. In some parts of England, it inhabits the seashore. Specimens from the United States have thus far been collected only in Illinois and Vtah."—Uhler. Van Duzee adds: Quebec, New York, Indiana and California. Solda coriacea Uhler 1872. Salda coriacea Uhler. Fifth Ann. Rip. U. S. Geog. Surv. for 1871, 1872, p. 421, No. 2. "Form similar to that of Salda littoralis Linnaeus, but much nar- rower, very elongate-ovate, black, highly polished, minutely shagreened. Head oblique anteriorly, distinctly shagreened, sericeous pubescent, the base moderately wide, slightly convex, forming a distinct neck; ocelli honey yellow, lacking the raised chevron in front of them, and having traces only of the oblique grooves and central line ; front moderately flat, the tylus prominently raised, polished, bald, cylindrical; the labrum much broader, acutely angular at tip, a little longer than the tylus, and of the same testaceous color, or both black. Eyes large, prominent, brown, placed very obliquely. Rostrum reaching to the posterior coxae, piceous, paler at base and tip. Antennae black, remotely bristly, the first two joints often paler above; the basal joint stout, increasing in thickness beyond the base; the second joint more than twice as long as the first, a very little enlarged at tip; the third and fourth longer than the basal, hungerford: aquatic hemiptera. 61 subequal, the third a little thicker, both slender on the ends. Pronotum subcampanulate, narrow, very much rounded in front, the lateral mar- gins flattened and a little reflexed, but tapering very slenderly in the di- rection of the collum, before reaching which it turns downward and fades out; the anterior lobe very narrow, but strongly convex, indented on the middle and constricted in front, more or less golden pubescent, and punctate in the depressed lines; the posterior lobe flattened, transversely a little wrinkled, shagreened, and somewhat pubescent; the posterior margin deeply concavely sinuated, the humeral angles produced, broad, flat. Scutellum densely shagreened, sparingly pubescent, a little convex at base, and depressed before the tip. Prosternum either black, or broadly margined each side behind with white, and, together with the disks of all the pleural pieces, pubescent and rugulose. Coxte terminated with piceous or testaceous, the femora pale piceous or yellowish, darker at the knees, and sometimes with a few brown dots on the sides ; tibiae yellow, infuscated at tip, and with the spines piceous; tips of the tarsal joints dusky or piceous, with the nails paler. Hemelytra highly polished coal-black, remotely set with shallow punctures, faintly golden pubescent, the costal margin strongly arcuated, at base broadly expanded, and a little upturned, the edge recurved, and the area very broad, the up- turned mai'gin continued tapering to near the tip of corium; the clavus bounded on the inner sub-margin and outer suture by impressed punc- tate lines; membrane almost as thick as the corium, black, tinged with piceous, sometimes with about three pale brownish spots in the longer areoles. Venter brilliant black, closely, minutely punctate, coated with sparse, fine pubescence. The hemelytra are M'ider at base than the pro- notum, and they gradually widen in their curve posteriorly, "Length to tip of venter 5-6 millimeters; to end of membrane 6-7 millimeters. Width of base of pronotum scant to full 2 millimeters. Full width across the corium 3-3 ^/^ millimeters. "The greatest number of specimens thus far acquired have been from eastern Massachusetts. Mr. Sanborn collected several near Andover; Mr. Scudder secured one in the vicinity of Lake Winnipeg; Robert Ken- nicott found it in British America, near Mackenzie river; other speci- mens have been sent to me from Northern Illinois; and the Museum of Comparative Zoology has specimens from British Columbia, collected July 14. The genital segment of the male is wider than long, almost gibbous, with the central attachments stout, curved toward each, and the exterior appendages long, slender, and overlapping each other when at rest. A specimen, the original type, was taken at Ogden, Utah, and another by B. H. Smith in the region of Denver. The nymph, from Massachusetts, has the usual 2-jointed tarsi, is broader and relatively flatter than the imago, and much resembles, particularly in the form of the abdomen, the common oriental cockroach." — Uhler. Van Duzee adds New York, New Jersey, Maine, and Ontario. Salda anthracina Uhler 1877. Uhler Bui. U. S. Geol. Surv. Ill, p. 438. 1877. "Form of S. coriacea, but still more slender, the pronotum narrower and more convex, and the -wing-covers very arched and decurving over the body like the shell of a terrapin. Deep, coal-black, shining. Head moderately narrow, minutely pubescent; the eyes very large, prominent, and oblique; face long, oblique, dull black, rugulose, with the impressed lines faint, and the shield of the vertex obsolete; base of head forming a distinct neck, coarsely shagreened and rugulose, a little flattened on top, rounded off' posteriorly. Rostrum reaching to the posterior coxae, piceous- black, paler at tip. Antennae stout and long; the basal joint long, black, not much thicker and but little shorter than the third; second about twice as long, yellow, black at base, dusky, and a little enlarged at tip; 62 THE UNIVERSITY SCIENCE BULLETIN. third and fourth dusky, subfusiform, stout, the latter a little shorter than the third. Pronotum like the basal half of a funnel, very narrow anteriorly, sparingly sericeous pubescent, finely, obsoletely punctate, and shagreened, the sides anteriorly compressed, the callosities obsolete, the transverse impressed line abbreviated at each end, punctate; the pos- terior margin concave, with the posterior angles produced, oblique; the lateral submargin a little flattened, coarsely shagreened, the edge reflexed, turned down anteriorly, and thinning out. Pectoral pieces rugu- lose in part, deep black. Legs yellow, the coxae black or piceous, with the ends more or less yellow; anterior femora with a few brown dots, tip of tibiae and last tarsal joint piceous. Scutellum coarsely, irregu- larly rugose, excepting the apex, which is nearly smooth. Hemelytra of almost equal thickness throughout, very convexly inflated, and decurv- ing on the sides and posteriorly, slightly pubescent, polished, obsoletely, remotely punctate, the punctures of the deep sutures coarse and distinct; the membrane hardly distinct from the corium, the basal thick nervure obsolete. Venter polished, closely golden pubescent. "Length to tip of venter, 4-6 mm.; to tip of hemelytra, 5i/^-7 mm. Width of base of pronotum, l%-2 mm. "Inhabits York county, Pennsylvania. Collected by the late Dr. F. E. Melsheimer, and by myself in the neighborhood of his farm." — Uhler. Van Duzee adds New Hampshire. Genus SALDULA Van Duzee, 1914. "Body oblong, oval, or sometimes obovate in brachypterous forms. Head subvertical. Ocelli usually very much approximate. Rostrum reaching to middle of intermediate coxag or posterior coxae. Antennae quite slender. Base of pronotum broadly emarginate, other structures very variable. Lateral margins straight or rounded. Callus by no means reaching lateral margin, extending further behind middle of disc. Scutellum longer than broad, impression far removed from base. Heme- lytra often variegated with silky black patches — Membrane furnished with four areas, more or less explicate or abbreviated, in this case attain- ing apex of abdomen. Third segment of posterior tarsus a little longer than second — Apex of last ventral segment of female produced and I'ounded. Type, Acanthia saltatoria L." Saldula major (Provancher) 1872. Provancher Nat. Can., p. 107, 1872. "Oval, robust, dull black, the upper surface remotely appressed, golden pubescent, and with a few erect, remote brown hairs. Head from above short and blunt, minutely, densely scarbrous, the base forming a neck, a little convexly elevated, the eyes moderately prominent, brown; front almost vertical, a little oblique, closely golden pubescent, triangularly de- pressed before the ocelli, the face a little flattened; tylus much shorter than the labrum, they and the ends of the cheeks and bucculse some- times yellowish. Rostrum generally reaching upon the base of venter, but sometimes a little shorter, piceous-black, becoming yellow at tip. Antennae very slender, black, pubescent and setaceous; the basal joint above and the second joint excepting the tip sometimes dull yellow, the former very short, not as long as the eye; second joint about twice as long, slender, much shorter than the last two united; third and fourth subequal, very slightly thicker than the second, a little subfusiform. Pronotum semilunate, short, depressed, dull black, minutely shagreened, but with the broad, thin, depressed lateral submargins more coarsely so, the margin a little turned up, but not abruptly reflexed; anterior lobe defined by a lunate, impressed, punctate line, hardly elevated, longer than the posterior lobe, and with a deeply indented point in the center; humeral angles broad, moderately prolonged, with a long tubercle next hungerford: aquatic hemiptera. 63 the outer angle; posterior margin deeply concave; the anterior angles rounded off, and the anterior margin with a narrow collum. Prosternum and pleurae shining black, golden pubescent, somewhat rugulose in places, very minutely scabrous. Legs black or soiled yellow, pubescent, and with some long erect hairs intermixed ; the femora when yellow more or less black beneath, and dotted with piceous on the two sides; tibiae dull yellow, piceous at base and tip, with the spines piceous; tarsi soiled yellow, with the basal and apical joints or their apices piceous; nails very pale piceous. Scutellum large, almost flat, slightly depressed on the disk, densely scabrous, and on the apical part a little rugulose. Hemely- tra dull black, almost flat, densely shagreened, and depressed golden pubescent; costal margin expanded and arcuated at base, the lobe up- turned, and rapidly tapering to a termination behind the middle; corium marked with short, white or yellowish, linear spots, of which two are on the inner line of the costal area, a longitudinal series of about four near the outer side of the discoidal area, and two or three on the inner area, and a small spot near the inner angle of the clavus; membrane soiled white or yellow, with a cloud at base and tip, and about two transverse series of fuscous oval spots in the areoles, sometimes with the apexes of the areoles more or less blackish, the nervules blackish, and the outer areole broad-triangular. Venter short and broad, shining black, closely and finely clothed with prostrate yellowish pubescence. "Length to tip of venter, 4:V2-QV2 mm; to tip of membrane, 8 mm. Width of base of pronotum, 2^/^-3 mm. "Inhabits Maine, Massachusetts, New York and Maryland, in Septem- ber; Texas, New Mexico, Missouri, Illinois, Michigan, Minnesota; Mac- kenzie river region, Robert Kennicott; Canada — near Saskatchewan river, and in the province of Ontario. "Specimens occur which are destitute of white spots upon the corium and clavus. I found numerous specimens upon the mud of the black marshes of Brighton and Cambridgeport, Mass., in the month of July. "The remarks under S. hig^tbris Say, in my paper printed in Dr. Hay- den's Bulletin, vol. II, Nov. V, p. 67, belong to this species." — Uhler as Saldula deplanata. Van Duzee's catalogue adds Quebec, Rhode Island, New Jersey, Penn- sylvania, Wisconsin and Kansas. Parshley adds New Hampshire. Saldula confluenta Say 1832. Acanfhia confluenta Say, Heteropt. New Harmony, 25, No. 5. Acanthia eonfliiens Say (emend, Le Conte), Complete Writings, I, 361, No. 5. Black; membrane of the hemelytra with a blackish band. Antennae pale at base; head and thorax immaculate; corium with a large marginal spot before the middle, and another at tip, two small spots; membrane with fuscous nervures and a continuous, blackish, arcuated band on the middle'; feet whitish, tarsi with blackish tips; thighs with an obsolete brown line; venter whitish at tip. "Length to tip of hemelytra one-fourth of an inch. "Inhabits the United States. "The band of the membrane does not reach the inner margin. It is equal in size to A. ligata." — Uhler as Salda confluens. Van Duzee's catalogue lists Quebec, New York, New Jersey. Saldula orbiculata Uhler 1877. Uhler Bui. U. S. G. G. Surv. Ill, p. 450, 1877. "Almost circularly ovate, deep dull black when invested with the clothing, but shining black when rubbed ; the upper surface invested with long, erect, golden and blackish, almost matted pubescence. Head wide, from above blunt and short; the front almost vertical, a little curved, 64 THE UNIVERSITY SCIENCE BULLETIN. clothed with erect black hairs and prostrate golden pubescence; front a little flattened; vertex with an indented point each side near the eye; ocelli small, pale piceous; base of head smooth, not obviously punctate, a little convex, forming a moderate neck; tylus very slightly prominent, shining, pale fulvous; lower edge of the clypeus fulvous, very slenderly recurved ; labrum broad, fulvous, invested with pale yellow bristles. Ros- trum testaceous, reaching upon the posterior coxae. Antennje short, moderately slender, the basal joint short and stout, testaceous; the sec- ond quite slender, pale piceous, testaceous at the base and piceous at tip, about twice as long as the basal one; it and the following joints with re- mote erect hairs; two last joints subequal, long, subfusiform, blackish, longer than the basal joint. Pronotum transverse, contracted at the column, flattened, the sides oblique but arcuated, with the submargin mod- erately broadly flattened, of almost uniform width throughout, a little upturned, thick, a little turned in and widened at the poserior angles; posterior margin moderately deeply concave, the humeral angles pro- duced, broad, short, scooped out; anterior lobe with the callosities feebly elevated, but not nearly extending to the lateral margin, the transverse line deeply seated ; posterior lobe about one-third the length of the an- terior one, indistinctly rugulose. Scutellum not distinctly punctate, short and wide, deeply lunately impressed on the middle, the surface beneath the dense pubescence polished, jet-black. Sternum jet-black, polished, finely whitish pubescent, the pieces of the mesopleura more or less white. Coxae piceous, paler at the tip; legs pale orange or fulvous, the spines and extreme tip of the tibiae, the basal joint of tarsi, the end of the apical joint, and the nails piceous. Hemelytra flat, disk-like, the costal margin almost semicircular, narrowly flattened and upturned, pale yellow, not wider at base; corium velvety-blackish, densely coated with prostrate golden pubescence and with longer blackish hairs; costal area very wide, with a testaceous spot on the middle entering from the outer margin, and a similar one before the tip; nearly one-half of the posterior margin running from the outer angle testaceous, and the inner edge of the clavus very narrowly of the same color ; disk with about four round bluish spots, and a similar spot near the apex of the clavus; membrane fuscous, a spot at the inner angle, the inner margin, the posterior submargin, and an apical spot, four spots on the bases of the areoles, and four near their tips pale testaceous. Venter black, terminated with white, and closely invested with prostrate whitish pubescence. "Length to tip of hemelytra, ZVz-^Vz mm. Width of base of pronotum, 11^-2 mm. Width across hemelytra, 2-2% mm. "This neat and unusual form of Salda has a very wide range of distri- bution. It occurs in Eastern Massachusetts, Pennsylvania, New York, Illinois, and Texas, and the Museum of Comparative Zoology has speci- mens from Calaveras and San Diego, Cal." — Uhler. Van Duzee adds Ohio. Saldula explanata Uhler 1893. ' Uhler, Proc. Ento. Soc. Wash., II, p. 383, 1893. "Subelliptical, deep dull black, but lustrous when the surface is rubbed, Similar to S. brachynota Fieber of Europe, but the pronotum is broader than in that species, and there is an absence of white marking on the basal part of the costa. Head and antennae black, the latter sometimes piceous at base; the rostrum piceous beyond the base, reaching to the posterior coxae. Pronotum nearly lunate, not deeply but broadly sinuated, with the humeral ends as wide, flat, rounded lobes, the lateral margins moderately curved, prominently reflexed, with the submargin concurrently broadly sulcated. Hemelytra a very little wider than the pronotum, with the costa wide, and acutely reflexed, corium with two or three small groups of obsolete pale specks; membrane with the areoles pale, and each marked in the middle with a black dot. Tibiae pale piceous on the middle. hungerford: aquatic hemiptera. 65 "Length to tip of membrane, 4% -5 mm.; width of pronotum, 2 mm. "Specimens were secured at City Canon, June 26, and also at Ogden and Alia."— Uhler. Van Duzee adds Idaho, California and Vancouver Island. Saldula dispersa Uhler 1877. Proc. Ento. Soc. Wash., 11, p. 383 (1893). "Very closely related to S. pallipes Fabricius of Europe, and having the white marks of the hemelytra essentially the same as in that species. The general form is also the sam.e, but the pronotum is a little narrower, with the lateral margins less curved, almost directly oblique. This insect varies so much in the amount and distribution of the white marking of the hemelytra that no satisfactory definition can be given of its orna- mentation. In general, however, it may be seen to have a broad black band across the base of the hemelytra connecting with the continuous black clavus, and thus forming the inner boundary of the large white spot behind the base of each corium. Behind this spot are several others of smaller size; the membrane has four pale cells, in each of which there is often a black streak. The cheeks are usually white, as is also the lower part of the tylus, and the inner side of the basal joint of the an- tennae. "Length to tip of membrane, ^V4,-^V2 mm.; width of pronotum, 11/4-2 mm. "A few specimens have the tibiae pale testaceous, with black knees and tip, and with dark spots at variable intervals. "Numerous specimens were secured at Salt Lake from June 13 to 25. Others were sent to me from various parts of Utah, and I found the species to be comparatively abundant in various places west of Denver, Colorado."— C//i/er. Van Duzee adds California. Saldula inte^'stitialis Say 1825 Acnnthia inferstitialis Say, Journ. Acad. Phila., IV, 324, No. 1. "Ovate, dull black, closely bronze pubescent, with a few remote, erect black hairs on the head, pronotum, and base of the hemelytra. Head from above broad and short, vertical, with a very short neck behind; the eyes large, brown, moderately projecting above the line of the vertex; base of head moderately convex, minutely shagreened, separated from the ocelli by a transverse impressed line; front almost flat, densely, minutely scabrous, the longitudinal groove obsolete; reflexed edge of the clypeus yellow or piceous; tylus a little prominent, slightly narrower inferiorly, yellowish, a little shorter than the labrum, bald; labrum broad, yellow, a little ridged on the middle line, with the sides sloping, the tip bluntly triangular and set with stiff hairs. Upper margin of the bucculje yellow; rostrum reaching behind the end of the posterior coxae, dark piceous, paler at tip. Antennae slender; basal joint short and stout, dull yellow, with a black line beneath and sometimes obscure on the middle above; second joint a little shorter than the third and fourth conjoined, yellowish or pale piceous, darker on the middle, slightly thickened at tip; third and fourth subequal, dull black, each longer than the basal one, and stouter than the second, subfusiform. Pronotum lunate, densely coated with prostrate golden pubescence and with longer black hairs on the margins and before; lateral margins moderately and abruptly reflexed, the sub- margin broadly depressed, of uniform width throughout, minutely scab- rous; surface generally minutely scabrous; the callosities forming a transverse ridge, sharply bounded by an impressed punctate line, which curves around the sides and stops at an indented point some distance be- hind the anterior margin; posterior margin deeply concave, the lobed humeral angles obliquely truncated and with a long tubercle near the 5— Sci. Bui. — 1669. 66 THE UNIVERSITY SCIENCE BULLETIN. outer corner. Scutellum feebly convex, closely minutely scabrous, lunately impressed, the apical division a little flattened, obsoletely rugulose, with the edge yellowish. Pectoral pieces polished, black, clothed with pros- trate whitish pubescence, the prosternum slenderly margined with white. Legs dull yellow, generally with a black line on the under side of the femora and tibiae; the femora often with piceous dots on the front and back faces; tibiae tipped with piceous, with piceous spines, and sometimes with piceous spots or faint bands at the base of the spines; tarsal joints tipped with piceous and the basal joint entirely piceous, the nails pale piceous. Hemelytra black, almost flat, minutely scabrous, with close, ap- pressed, golden pubescence, and with longer, remote, black hairs exteriorly and basally; the costal margin moderately arcuated, with the edge abruptly, narrowly recurved, and black or rarely piceous; corium with four or five whitsh oblong spots, of which there is a double one on the costal area behind the middle and a similar one near the tip, a large cen- tral one on the discoidal areole and a smaller one farther back; and at the tip of this areole, on the suture, is a larger triangular spot, or very small white spot behind a velvety-black one near the tip of the clavus; membrane dull whitish, dusky at base and tip, with black nervules, and across the middle a series of oblong, blackish spots. Venter black or tinged with piceous (or sometimes pale brownish) ; the apical segment entirely, or only a broad margin, whitish. "Length to tip of venter, 3-4 mm.; to tip of membrane, 4-5 mm. Width of base of pronotum, l%-2^4. mm. "Inhabits Missouri, Mr. Say. Specimens in my own collection were taken at Saint Joseph, Mo., by Mr. E. P. Austin; by myself at Andover, Mass.; and near Baltimore, on the dark sand of a loamy spot near a brook, in May and June; also in Dakota, Nebraska, and Illinois. Some varia- tion occurs in this form, such as the greater expanse of the white spot upon the apex of the corium, and of the pale colors of the prosternum and \egs:'—Uhler. Van Duzee adds: Quebec. Ontario, Maine, New York, New Jersey, Pennsylvania, Florida, Indiana, Michigan, Colorado, Texas, New Mexico, Idaho, and California. . ' Saldula separata Uhler 1878. Uhler, Proc. Bost. Soc. Nat. Hist., XIX, p. 432, 1878. "Black, minutely, sparingly pubescent above; general form of S. inter- stitialis Say. Head large, eyes brown, large and very prominent; face minutely, densely punctured, clothed with erect hairs ; cranium wider than in the preceding species, having a small yellow spot each side against the eyes, on a line with the amber-yellow ocelli; lower margin of the clypeus recurved, the tylus and labrum bright yellow, the rostrum, excepting its immediate base, piceous, extending. a little beyond the base of the posterior coxae. Antenna black, the basal joint yellow, black underneath excepting the base and tip; the second joint almost twice as long as the basal, third longer than the basal and shorter than the fourth. The base of head longer than in the preceding species. Pronotum obsoletely punctured, hardly polished, clothed with erect pubescence; the sides ob- lique, slightly curved, the callosities more polished, connate, forming a single transverse elevation, with a rounded pit in the middle; behind it is an "impressed, punctured line. Pectus polished black, obsoletely wrinkled, sparingly pubescent. Legs testaceous; the coxs more or less infuscated; anterior femora black on the middle underneath, the intermediate and posterior pairs with a black spot beneath near the tip, and clothed with thick, whitish pubescence; tip of tibiae and also of tarsi blackish. Hemely- tra dull black, obsoletely rugulose, sparingly clothed with erect pubes- cence, widest just behind the middle; the corium with a yellow dot on the exterior margin near the tip, usually also with three or four more minute ones on the middle suture and one at tip of clavus. Membrane sometimes hungerford: aquatic hemiptera. 67 whitish, with a large black spot at the base inwardly, a small subquadrate one against the base exteriorly, and behind this an orange spot which is bounded behind by another black spot; the nervures blackish. Others have the membrane black, with a yellow spot against the exterior margin and a few pale vestiges on the middle. Venter, black, more or less tinged with piceous, polished, very remotely pubescent, minutely inconspicuously punctured, tip of the genital segment broadly white. Length, 4-4 1/^ mm. Humeral breadth, 1 V2 mm. Extreme width of hemelytra, 2 mm." — Uhler. Distribution: "Canada, New Hampshire, Massachusetts and Pennsyl- vania."— Vail Diizee. Parshley adds Vermont. Saldula reperta Uhler 1877. Uhler, Bui. U. S. G. G. Surv., Ill, p. 447, 1877. "Closely resembles .S. marginaUs Fallen. Deep, dull black, sparsely clothed with golden prostrate pubescence, and the head and pronotum with a few erect black hairs. Head above broad and blunt, the base form- ing a short neck; the surface minutely scabrous; eyes prominent, brown- ish, moderately oblique; front moderately narrow and flat, not distinctly arched at base; the lower margin of the clypeus callous, feebly recurved, testaceous, black in the center; tylus and labrum forming an arched bridge, dull ochei'ous, the former a little concave on the sides inferiorly, the latter piceous at tip and a little pubescent. Rostrum reaching upon the intermediate coxEe, dark piceous, paler at tip. Antennse moderately stout, clothed with pale, stiff hairs; basal joint dull yellow, black beneath; second piceous, paler at base and tip, not twice as long as the basal one, and a little thickened at tip ; third and fourth dull blackish, subfusiform, subequal, each longer than the basal one. Pronotum transverse, sub- trapezoidal, rather flat, with the sides very oblique, hardly curving; the submargin broadly depressed and gradually narrowing toward the front; the callosities feebly elevated, deeply and broadly foveate in the center, bounded by a deeply impressed line; the surface minutely and densely rugulose ; posterior m^argin very slightly concave, with the humeral angles moderately produced, very broad, and with a large, low fold near the outer angle. Scutellum scabrous at base, minutely, transversely wrinkled on the apical half; the central impression lunate, distinct. Legs dull testaceous, very hairy, more or less marked with piceous on the femora, particularly beneath, on the tibiae, somewhat in spots, the tips, spines, and the basal and apical joints of the tarsi piceous-black, the nails dull tes- taceous. Sternum and under side of the body shining black, minutely, closely whitish pubescent; the extreme edge of the prosternum and of the ventral segments and a broad end of the genital segment of the female whitish. Hemelytra deep black; the corium closely yellow and black pubescent, densely shagreened, the costal margin moderately arcuated, broadly and continuously flattened, recurved from the base to behind the middle; the costal area with a testaceous small spot behind the middle and two smaller parallel ones near the tip, the middle nervure with a spot near the base, and the middle areole with a larger spot at tip and two or three smaller ones near the tip; the clavus with a small yellow spot near the tip; membrane dull white, fuscous at base and with a broad cloud at tip, a transverse series of oblong fuscous spots across the middle and a spot at the tip of the exterior areole; the nervures piceous or black. "Length to tip of hemelytra, 4-4% mm.; to tip of venter, 3y2-4 mm. Width of base of pronotum, 1 1/2 mm. "A few specimens from the Museum of Comparative Zoology, collected in Cambridge, Mass. "This is a robust little species, very closely related to S. inter stitialin Say, and perhaps only a variety of it. But the different shape of the pronotum, with the other details, will at present serve to separate it." — Uhler. Distribution: Quebec, New Hampshire and Massachusetts. 68 THE UNIVERSITY SCIENCE BULLETIN. Saldula xanthochila Fieb. 1859. Fieber, Wien Ent. Monat., Ill, p. 234 (1859). "Marginal line black like the pronotum. Outer basal angle of the membrane with short black cross stripes on the angle of the corium. Cells of the membrane with elongate dots or spots. At the end of the first cell a smaller square blackish spot. Sides of the pronotum straight. Corium somewhat broadened behind, on the median field on the principal vein with four small whitish spots; outwardly two elongate white spots, at the angle of the corium with two larger spots, sometimes confluent. Tip of clavus with roundish spot. Antennae black. First segment yellow, black beneath. Base of rostrum and legs yellow. Femora black beneath with a semicircle on the end. Tibia at base and tip, and first and third tarsal segments, black. Length two lines. Often confused with S. sal- tatoria." Distribution: New York, New Jersey, Colorado, Utah, Nevada and California. Saldula xanthochila var. limhosa Horv. 1891. Horvath, Revue d' Ent., p. 80, 1891. "Size smaller. Lateral margins of pronotum broadly margined with pale. This pale margin about subequal to the fore femora. Spot at base of corium smaller. Length, 3 mm." "Differs from the type only by the yellow border of the pronotum being broader. The size much smaller, and the black spot at base of the corium less developed." Found in New Jersey and Florida. Saldula pallipes Fabricius 1794. SaMa pallipes Fab., Syst. Rhyng., 115, No. 12. H. Schf.. Wanz. Ins., VI, fig. 600. "Moderately long-oval, thickly clothed above with appressed golden pubescence, and fringed with almost erect pile. The head, fore part of the pronotum, and basal parts of the hemelytra with erect black hairs. Head from above short and blunt, the front nearly vertical, dull black, moderately flat, minutely granulated, clothed with appressed golden pubescence and some longer black erect pile; inferior margin of clypeus emarginated in the middle, thick, elevated into a slight ridge, yellow, smooth ; tylus a little prominent, bald, narrowing inferiorly, . and, to- gether with the labrum, reddish-yellow; the latter a little longer, pubes- cent, infuscated at tip; rostrum reaching to the tip of the middle coxae, piceous; antennae black, with short hairs; the first and second joints more or less fulvous, black above and beneath. Ocelli black, Pronotum very transverse, minutely scabrous, the sides arcuated, flattened, the edge a little reflexed; the posterior margin very concave^ across the scutellum; the humeral lobes roundly produced ; callosities occupying half the length, moderately prominent, the central fovea deep and transverse, the side impressions obsolete, the bounding furrow deep; scutellum convex, the central depression deep, sharply defined behind; the base finely scabrous, the apical half rugulose. Hemelytra slightly convex; clavus black, the apex with a large or small wedge-shaped yellow spot; corium black at base, sharply distinguished from the rest of the pale yellowish surface; the basal one-third of the costal margin rounded and a little broadly ex- panded and turned up, the margin black, and with a black spot at the apex; costal area with two long contiguous black spots, nearly forming a black streak, the second interrupted by a white dot; between the first and second nervures basally a black spot, with a broad ring of the ground-color around it; below this ocellus is a black spot; at the end of the second nervure is another black spot, sometimes extended to the inner hungerford: aquatic hemiptera. 69 angle; and beyond this nervure, on the disk, is a long black spot; nerv- ures black, sometimes pale posteriorly, and occasionally destitute of the intervening black spots; membrane pale yellowish or white; the nervures piceous or black, excepting the exterior one, which is generally pale, with a black spot at its tip; across the middle is a series of oblong spots, and sometimes a larger one near the base of the third cell, the apical margin generally infuscated; sternum black, the presternum slenderly margined behind with yellow; legs yellow, with fine, short, yellow hairs; the femora having two rows of brown points on the inner and outer faces, the under side with a blackish streak; tibiae with black spines and apex, the anterior pair with a blackish line on the under side; apex of the last tarsal joint black, the nails pale brown; abdomen black or. blackish, the posterior edges of the ventral segments whitish, that of the apical segments broadly whitish. "Length, 3-5 mm. Width of pronotum, IVa^-IV^. mm. "Dr. Stal reports this species to have been taken in Sitka. Speci- mens belonging to the Museum of Comparative Zoology, kindly sent to me for study by Dr. H. A. von Hagen, were taken at San Diego and Bard's Ranch, Cal. These specimens are larger than those from the Rocky Mountain region, of which many have passed through m.y hands, from various localities in Utah, New Mexico, etc. In the western sub- urbs of Denver, Colo., it may be met with in untold numbers on the dark, damp, sandy, and muddy soil, during the month of August. A few speci- mens occurred to me on dark, damp soil, next the stream of water run- ning down the Beaver Brook Gulch, and also in similar spots in Clear Creek Canon. I can find no characters to separate it from specimens which I collected in Hayti on the marshy banks of the Grand Anse river in May, nor from Cuban specimens received from Professor Poey. It occurs also in New Jersey and on the dark mud of the sea coast of Maryland. "Dr. Packard collected it near Georgetown, Colo., July 8, at an eleva- tion of 9,500 feet, and also near Salt Lake, Utah, July 27:'—Uhler. Reported also from New York, Ontario and Nevada. Parshley adds Maine, New Hampshire, Vermont, Rhode Island, Con- necticut and Massachusetts. Saldida laticollis Reuter 1875. Reuter, Pet. Nouv. Ent., I, p. 544, 1875. "Similar to S. saltaforia and referrable to the same division, but much larger, pronotum strongly transverse, with an arcuate impression and a profound foveola on the disk. Middle of the sides straight. Hemelytra marked as in S. saltatoria, but the external margin of the corium with a large single spot (often paired) situated immediately behind the middle. Length, 4.75 mm." Saldula sphacelata Uhler 1877. Uhler, Bui. U. S. G. G. Surv., Ill, p. 434, 1877. "Elliptical, dusky, testaceous, dull, clothed above with minute, close, appressed, fuscous pubescence. Head stout, obliquely curving, almost vertical, pale tawny, inscribed with black on the vertex and with a black spot behind, the base convex; clypeus longitudinally indented at the base of the tylus; front with an indented, oblique, brown line each side, and the usual impressed line in the middle; basal margin of the eyes and an im- pressed line bounding the quadrangular bed of the ocelli blackish ; ocelli honey-yellow. Rostrum reaching upon the base of the posterior coxae, slender, yellowish, becoming piceous toward the tip. Antennae stout, setose, pale flavo-piceous, more or less dusky, particularly on the last two joints, the basal pale, short, thickened toward the tip; second joint very long and slender, faintly thicker at tip; fourth much longer than 70 THE UNIVERSITY SCIENCE BULLETIN. the basal and a little shorter than the third. Pronotum transverse, closely punctate, short, the sides very oblique, broadly reflexed; the an- terior margin truncate, M^ith a slender collum extending along its entire length, the anterior anglesi rectangular; the posterior margin concavely a little sinuated, with the outer angles moderately lobed, truncated at the end, and a little folded, and bounded on the inner side of the fold by an impressed short line; the anterior lobe moderately convex, variegated with black, transversely impressed, and with a few coarse punctures in the impression ; the impressed line environing the lobe sharply defined, brown, and set with small punctures. Presternum whitish, a little inscribed with piceous, finely sericeous pubescent; mesopleuras black, sericeous pubescent, more or less bounded and invaded with tawny; metapleurae tawny, seri- ceous pubescent. Coxse a little piceous at or near the base; legs tawny; the femora more or less dotted with brown, pubescent; the apex and spines of the tibi« and the ends of the tarsal joints dark piceous; nails pale piceous. Scutellum finely, closely punctate, yellow, blackish on the base and disk, finely sericeous pubescent. Corium pale, dull clay-yellow, remotely sericeous pubescent, paler at base and lip, a little more coarsely punctate; the costal margin broadly arcuated at base, the expansion there wide and thin; costal area broad, pale, infuscated on the inner side, sutures, and nervures; centers of a few of the outer, discal, and apical areoles whitish, with dusky nervules; the clavus dusky; membrane pale, dull testaceous, with strong, slightly curved, piceous nervules, inclosing five long areoles. Venter pale, obsoletely punctate, closely invested with pale, minute, prostrate pubescence. "A varity of the male is more dusky on the hemelytra, has the disk of the venter (excepting the edges of the segments) piceous, and irregular series of brown dots on the sides. The male genital segment is long, semi- oval, densely set with long hairs. "Length to tip of venter, 4-5 mm. ; to tip of membrane, 5-6 mm. Width of base of pronotum, l%-2 mm. "This species is exceedingly abundant on the discolored sandy and marshy brown spots of the tide-water districts of eastern Massachusetts and Maryland. Some of these tracts of country are no longer within the reach of the tide, although they were at a former period; but still these insects remain there, although apparently in diminished numbers. The salt mud seems to afi'ord them the conditions best suited to their develop- ment, and on such spots they may be found in all stages of development and in unnumbered multitudes. As far as I was able to collect them (which was difficult because of their activity and close resemblance to the soil), I found the males to be in the proportion of two to fifteen females. Yet I do not think that this would be the full proportion if we were able to collect them exhaustively over a locality in which they occurred of aver- age abundance." "Specimens were collected by me at Newtonville, Chelsea, Lynn, and Braintree, Mass., in July; also on Sinepuxent Beach, Maryland, in July and August. "Specimens have also been found in Cuba, by Prof. Felipe Poey, which were smaller than the average of those from the United States. "An individual from San Diego, Cal., has the scutellum black, except- ing only some small marks of yellow on the sides, and the punctures of the scutellum are coarser than those of the pronotum. Its length is only 4% mm. and the width of the pronotum is 1% mm." — JJhler Parshley adds Maine and Rhode Island. Saldula opacula Zett. 1840. Zetterstedt, Ins. Lapp., Column 268, 1840. "Elongate oval, black, sides of the thorax widely impressed. Scutellum and clavus with golden hairs, the latter with an obscurely pale spot near the apex. Corium with a few obscure pale markings; lateral margin, hungerford: aquatic hemiptera. 71 except at the base and extreme apex, narrowly testaceous; membrane ob- scure, its outer margin testaceous; nerves black; legs testaceous; apex of tibias and tarsi black; antennae obscure. "Length, IVa lines." Parshley: Maine and Massachusetts. Saldula scotica Curtis 1835. Curtis, Brit. Ento., XII, pi. 548, 183.5. "Black, covered with black semi-erect hairs, and short, pale, appressed pubescence. Thorax with the sides straight. Elytra with the sides gently rounded; disk of each with several pale, roundish spots, varying much in number, and often entirely obliterated; membrane dark, the nerves black. Legs black, a line along the top of each thigh, a band above the apex of each tibia, and the second joint of the tarsi, pale. Antennae black. "Length, 2% lines." Saldula pellita Uhler 1877. Uhler, Bui. U. S. G. G. Surv., Ill, p. 433, 1877. "Broad, ovate, dull ochreo-testaceous or clay-yellow, above clothed with erect, moderately long, close, fuscous pubescence, which is longer on the head and margins of the pronotum. Face longer, more oblique and less vertical than in S. sphacelata, the front less prominently con- vex, and the sutures not so distinct; vertex either dusky, or with a small, black spot on the middle, and with a narrow black base; its sur- face very flat and the eyes very large and prominent; the base of the head forming a distinct neck, which is broader than the diameter in front of the eyes. The tylus pubescent but the cheeks and gula bald and whitish. Antennae long, dusky, beset with long, dark, hairs; the two first joints clay-yellow; the basal one stout, short, a little thicker toward the tip, second longest, feebly thickened on the extreme tip; third and fourth scarcely thinner than the second, the fourth a little shorter than the third, but not much longer than the basal joint. Rostrum reaching near to the middle of the posterior coxae, pale at base, piceous at tip. Pronotum polished, transverse, clothed with long, erect, dusky pile, re- motely punctate; the lateral margins oblique, with the edge broad, thin, recurved; the anterior angles blunt, but almost rectangular; the collum slender but distinct, blackish; anterior lobe high, very convex, dusky in front, and bordered by a deeply impressed, piceous line, having a few coarse punctures acivss the middle, and remote finer punctures in the impressed lines; pleurje pale, finely sericeous pubescent; sternum paler, bald, darker posteriorly; the impressed arc in front of the anterior coxse piceous. Coxae pale yellow; legs dark luteous, with dusky hairs; thighs somewhat pointed with brown; the tibiae with a piceous tip and spines, and the tips of the tarsal joints piceous, the nails paler piceous. Scutel- lum a little convex at base, polished, pubescent, a little punctate on the base and middle, which are also more or less infuscated, Corium broad, pale luteous, closely, obsoletely punctate, erect, pubescent; the base of costal margin expanded and broadly rounded, the costal area very wide, the sutures and outer margin brownish; membrane paler, the nervures long and rather straight, piceous, bounding five large areoles. Venter highly polished, clothed with long, pale pubescence, minutely and obso- letely punctate. The membrane is not conspicuously distinguished at first sight from the corium, and the latter when held up to a strong light appears flecked and dotted with brown. The disk of the venter is occasionally a little infuscated. Male genital appendages apparently like those of the preceding species. Occasionally there is a series of brown dots on the venter near the connexivum. "Length to tip of venter, 4-5 mm. Length to tip of membrane, 5V2-6V4, mm. Width of base of pronotum, 1^2-2 mm. 72 TilE UNIVERSITY SCIENCE BULLETIN. "Very abundant near the sea coast of eastern Massachusetts. Near Chelsea, July 9; and near Charles river, in the vicinity of Newtonville. "The posterior angles of the pronotum are obliquely protracted, flattened, obliquely truncated, and with a slight convexity next the outer angle." — Uhler. Saldula lugubris Say 1832. Aranthifi bif/uhris Say, Heteropt. New Harmony, 34, No. 3. "Body black, subopaque. Head between the antenna with three yel- lowish points; antennae, first and second joints dull yellowish before. Thorax and scutel immaculate. Hemelytra immaculate on the corium, or with an obsolete dull yellowish point on the middle of the tip; mem- brane with two or three obsolete dull yellowish spots, inner margin and tip. Beneath with a yellowish spot before each of the anterior feet. Feet pale yellowish; tibi?e and tarsi more dusky; thighs, particularly the anterior and posterior pairs, with a more or less dilated black line toward their tips; coxae black, the anterior pair yellowish at tip, remain- ing pairs slightly tipped with yellowish. "Length to tip of hemelytra, less than three-tenths of an inch. "For this species I am indebted to Nuttall, who obtained it in Mis- souri."-— Uhler. Saldula elongata Uhler 1877. Uhler, Bui. U. S. G. G. Surv., Ill, p. 448, 1877. "Long-elliptical, narrower anteriorly, dull black, clothed above with prostrate yellowish pubescence, and with a few erect black hairs on the head and pronotum. Head dull black, front very oblique, long and mod- erately narrow, convex, forming an 8-sided tablet, which is bilobed above, grooved down the middle, and with the lower side-margins of the clypeus a little carinated, black; an oblong callous spot each side next the eyes yellow; tylus smooth, black, yellow at tip; labrum piceous, pubescent, yellow along the middle line; eyes brown, oblique, and very prominent; base of head convex, forming a rather long neck, densely, minutely granulated; tip of the lower cheeks orange; bucculae and throat dull black, minutely scabrous and whitish pubescent. Rostrum reaching behind the intermediate coxae, blackish-piceous, paler at tip. Antennae slender, as long as from the tylus to tip of clavus, piceous; the basal joint stouter, fulvous at tip; the second very long, much more than twice the length of the first, pubescent; third and fourth dull black, pubescent, slenderly subfusiform, subequal, each about two-thirds the length of the second. Pronotum subcampanulate, transverse, densely clothed with prostrate golden pubescence, the anterior part very narrow, with the sides steep, the callosities prominent, convex, rugose, deeply indented on the middle and obliquely so each side of it; posterior lobe about one-half as long as the preceding, deeply, squarely sinuated, the humeral angles obliquely prolonged, flattened, longitudinally sulcated, rugose; the sides broadly flattened, tapering anteriorly, the margin ab- ruptly recurved, and fading out next the collum. Pectus polished black, finely, prostrate, whitish pubescent; prosternam very slenderly mar- gined with white. Legs dull testaceous, the femora more or less piceous beneath and on the front and hind surfaces; tibiae with piceous knees, spines and tip; tarsi dull testaceous, the basal and apical joints piceous, the nails dull testaceous. Scutellum coarsely, densely scabrous on the prominent base, the impression very distinct, arcuated; the apical divi- sion transversely rugulose. Hemelytra narrow, thin, very minu-tely scabrous, with a very few coarse punctures on basal and costal areoles; clavus black, golden pubescent, having a few coarse punctures and a wedge-shaped yellow spot next the tip, placed on a velvety-black spot; corium yellowish, the costal margin broadly arcuated, the base broadly flattened and turned up, the edge black; costal area broad and long, the base blackish, the middle with a quadrate spot, and near the tip a HUNGERFORD: AQUATIC HEMIPTERA. 73 roundish one; nervures coarse and deep black; the inner areole black, with two yellow small spots next the outer margin and before the apex, and with a larger one at the inner angle ; the central areole black at base, next a large yellow spot, and then black with three moderately large yellow spots, the last one is separated from the apical margin by a black line; membrane pale yellowish, blackish at base, with black nervules margined with blackish, and spots at their tips; a marginal blackish line on the apical two-thirds of the outer nervule, and with a transverse series of streaks; oblong spots on the middle of the areoles. Venter black, minutely sericeous pubescent; the middle of the disk and the posterior part of the genital segment yellowish; posterior margin of the segments pale piceous. "Length to tip of venter, 5 mm.; to tip of hemelytra, 6 mm. Width of base of pronotum, 2 mm. "One female, the type, is the only specimen that I have seen. It is from British Columbia, and belongs to the Museum of Comparative Zoology. It seems to be closely allied to the European S. latipes H. Schir—Uhler. Saldula luctuosa Stal 1858. Salda luctuona Stal, Eugenies Resa, Hemipt., 263, No. 123. "Oval, blackish, moderately polished, having the form of S. palHpes, but the colors and markings similar to S. littoralis. Head black, clothed with fuscous hairs, with eyes somewhat broader than the anterior width of the pronotum; eyes moderately prominent. Antennae somewhat more than half as long as the body, blackish-fuscous. Rostrum blackish. Pronotum three times as wide as long, anteriorly about one-half as wide as at the base, the posterior margin broadly sinuated, the sides scarcely arcuated with the margin, slenderly reflexed; blackish, clothed with some- what depressed fuscous pile; the anterior lobe a little elevated. Scutel- lum blackish. Hemelytra blackish, sparingly clothed with prostrate pubescence, the costal margin at base somewhat expanded; membrane very distinct, infuscated, having four areoles. Beneath blackish. Legs obscurely fusco-testaceous, the tibiee and tarsi somewhat paler, the former sparingly bristly. "Length, 4 mm. Width of pronotum, IVs mm. "Inhabits San Francisco, Calif." — Uhler. Saldula saltatoria Linn 1758. Linneaus, Syst. Nat. Edn., 10, p. 448, 1758. "Oval, convex, black, densely clothed with very short yellow hairs. Clavus with a narrow, pointed, subapical, yellow spot; corium; on the anterior margin two long yellow spots, interior to these a row of three spots, the second and third round and white; beyond these a faint, long, yellow ring on the basal half of the disk, followed by a long yellow streak. Legs yellow. "Head. Clypeus, on its anterior margin, and the face, pale or dusky yellow. Antennas black, first joint above, and generally the second before the apex, yellow-brown. Eyes black. Ocelli reddish. Rostrum piceous; labrum yellowish. "Thorax. Pronotum roundly narrowed to the front; sides flattened, but raised within the hinder angles, the margins rounded, narrowly re- flexed ; posterior margin deeply, somewhat squarely concave across the scutellum, the ends roundly produced over the base of the elytra; disk very finely punctured, the callosity occupying nearly two-thirds of the length, the posterior furrow deep, the single central fovea deep. Scutellum convex, slightly shining; basal half finely punctured, posterior half very finely crenate; the depression large, posteriorly straight. Elytra dull; clavus with a narrow, pointed spot before the apex ; corium, sides widely flattened as far as the middle; the margin with a long, narrow, yellow spot in the middle, and a shorter one before, and not reaching to, the 74 THE UNIVERSITY SCIENCE BULLETIN. apex; disk outside the first nerve, with three spots in a row, one longish, dull yellow, before the middle, the two others round and whitish, one of them rather beyond the middle, the other opposite the second marginal spot; beyond the first nerve, on the basal half, a long faint ocellus, formed by a narrow, yellowish, oval ring, enclosing a space of the ground color, its basal end being clearer; in a line with this, near the posterior margin, a long yellow streak (sometimes there is a faint, yellowish, interrupted line more towards the inner margin ; and sometimes the whole of the yellowish marks on the corium are of larger size, giving a more speckled appearance) ; membrane yellowish, the suture and nerves black; the first nerve often yellow at its base; between the nerves, beyond the middle, a transverse row of long blackish spots; nearer the base an irregular black spot in the second, third, and fourth cells (sometimes in the second and third only) ; margin with a long black spot at the end of the first nerve, preceded and followed by a yellow spot; the rest of the margin fuscous- brown, sometimes yellowish internally. Legs pale yellow; thighs with fine, short, yellow hairs on the inner and outer sides, with a row of brown punctures; hinder side of the first and second pairs with a black stripe; apex narrowly black, preceded by a clear space; tibiae blackish at base and apex, the first and second pairs with a long, subannular, brown spot in the middle; third pair with short, distant, black, spinose hairs; tarsi; first and second joints black, the second, and sometimes the base of the third, yellow; claws brown." "Abdomen, in the female, the last segment beneath, posteriorly pale ochreous. "Length, iy2-2 lines. "Abundant on the margins of ponds and ditches during the summer, and in winter in moss on damp walls, etc." Reported from New York and Illinois. Parshley adds Massachusetts, Rhode Island and Connecticut. Genus MICRACANTHIA Reuter. "Body small, rather short. Gula short. Eyes very much exserted, strongly converging anteriorly Ocelli slightly distant. Rostrum nearly reaching apex of posterior coxae. Antennae rather short, second segment scarcely double the length of the first. Apex of pronotum much narrower than the head with the eyes, sides straight or subsinuate before the apex. Callos by no means reaching lateral margins, extending farther behind middle of the disc, margin of base broadly emarginate. Scutellum longer than wide, base entirely visible, impression far remote from base. Hemel- ytra entirely or almost entirely {Humilis Say) opaque or sericeo-nigra, embolium discolored, entirely distinct from corium; veins of corium en- tirely obsolete. Apex usually subacuminato-rotundate; first area or anterior base produced before the proximal area by one-quarter or one- fifth part of its own length. Apex most often distinct, sometimes (Humilis Say) placed very little above apex of proximal area. Third segment of post-tarsi a little longer than second. Type Acanthia margi- nalis Fall." Micracanthia humilis Say 1832. Acanthia humilis Say, Heteropt. New Harmony, 35, No. 4. "Elliptical, black, velvety, above closely invested with minute yellow prostrate pubescence; the eyes very large, prominent, round, brown, placed obliquely. Head at base, with a narrow neck, conforming to the width of the front of pronotum, black, dull, minutely scabrous; the front very narrow between the eyes, from above blunt, short, a little fiattened, with two indented points each side and one in the middle; tylus slightly prominent, and together with the labrum, pale ocherous or yellow, the ends of lower cheeks also ocherous. Rostrum reaching upon the pos- terior coxae, pale piceous. Antennae testaceous, slender, and moderately piungerford: aquatic hemiptera. 75 long.; the apex of the second joint and all of the third and fourth joints blackish; the second joint about twice as long as the basal one and much more slender; the third and fourth slender, subequal; all but the basal one with erect hairs. Pronotum trapezoidal, transverse, very narrow in front, the sides oblique, a little prominent at the shoulders, the lateral margins very slenderly reflexed, decurved, and lost before reaching the anterior margin; the surface very minutely scabrous; anterior lobe moderately elevated, transversely indented on the middle, the impressed line distinct but not very deep; posterior division a little shorter, mod- erately flattened; posterior margin a very little sinuated, the humeral angles oblique, short, flat, the outer angles subacute, with an oblong tubercle placed next the outside. Scutellum long, moderately depressed in the middle, and more deeply each side, coarsely scabrous at base, finely rugulose on the apical division. Pectus and sternum jet-black, highly polished, closely covered with appressed, fine, white pubescence. Legs pale testaceous; the coxse black, with white tips; femora broadly banded near the tip with fulvous; tibiae piceous at tip, and with pale piceous spines; apex of the last tarsal joint black, the nails pale piceous. Hemelytra velvety-black, minutely, densely clothed with black and golden pubescence, minutely punctate; the costal margin broadly arcuated, with the edge narrowly reflexed; the costal area broad, pale yellow or white, with a small, black, longish patch at base, another oblong, large spot behind the middle, against the inner margin, and a trace on the outer margin, and the tip vdth a transverse black spot; nervures black; middle areole with an oval spot near the outer nervure, basally, a round one a little way behind this, a few specks behind the middle, a dot near the apex inwardly, and a dot near the inner tip of the clavus pale yellow; membrane pale yellow, a little clouded at base and on the apical margin, the apex with a piceous spot on the apex of the outer areole; nervures piceous; the areoles with a transverse series of oblong fuscous spots (sometimes the spots are interrupted, forming a partially double series.) Venter black, clothed with prostrate white pubescence, the posterior mar- gin of the segments slenderly piceous; the apical segment of the female broadly white. "Length to tip of hemelytra, 3-3% mm. Width of base of pronotum, IVi mm. "Common in Maryland, within the limits of the metamorphic belt, upon damp sand formed by the disintegration of the rocks, near creeks and brooks, in June and July. It is also common in Northwestern and North- ern Florida; and specimens have been sent to me from Texas, Illinois, and Pennsylvania. I have also collected it in Cambridge, Mass., and in the vicinity of Washington, D. C. It occurs likewise in western North Carolina and in Georgia. It is of precisely the same form as iS. cincta H. Schf., of England and France, agreeing with that species in most of its details, and, upon sufficient comparison, may prove to be the same species." — Uhler. Also reported from Maine, Ontario, Rhode Island, New York, New Jersey, Ohio, Colorado and California. Parshley adds Massachusetts. Micracanthia pusilla Van Duzee 1914. Van Duzee, Trans. San Diego Soc. Nat. Hist., II, p. 32, 1914. "Size and much the aspect of humilis Say, but with broader elytra. Elytra deep black with two white costal spots and the membrane strongly distinguished. Length 3 mm. "Head as in humilis, black, with a transverse white line at the base of the tylus. Antennae black, the joints subequal; the first a little shorter, the second longer than the third and fourth. Rostrum black. Pronotum broader posteriorly than in humilis, sides nearly straight, the humeral angles a little more rounded; hind margin broadly but shallowly exca- vated. Scutellum as long as broad, with a shallow transverse impression, 76 THE UNIVERSITY SCIENCE BULLETIN. and with the pronotum opaque, black and closely minutely sericeous pubescent. Elytra with a somewhat longer pubescence ; deep black becom- ing velvety black toward the apex of the corium and on the tip of the clavus; corium with a square whitish spot resting on the costa and a double one close to the apex; usually there is a small white point on the middle of the corium, one at the inner apical angle and another near the tip of the clavus. Membrane strongly differentiated, whitish hyaline, a little enfumed, the nervures strong, brown; the areoles with a brown sub- apical mark and sometimes another near the base. Beneath and legs black, the knees, tibise except at base and apex and the tarsi, their tips excepted, pallid. In the female the apex of the abdomen and sometimes the slender hind margins of the ventral segments are pale. "Described from three males and two females taken along the San Diego river at Lakeside, May 7, 1913, and from a moist ravine at Alpine in June. Dr. J. C. Bradley also took this species at Sisson, Cal., in August, 1908. The species can be easily recognized by its small size, intensely black color, the strongly distinguished membrane and the four white marginal spots on the elytra." — Van Duzee. Genus lOSCYTUS Reuter 1912. "Body oblong. Head subvertical, gula rather brief. Eyes distinctly distant from pronotum, exserted, anteriorly moderately convergent. Part of vertex bearing ocelli slightly elevated. Apex of rostrum reaching inter- mediate coxae. Antennse incrassate, shortly thickly pubescent, sparsely pilose. First segment rather long. Hemelytra laterally little rounded, destitute of white markings. Interior veins of corium obsolete. Embolium entirely distinct from corium. Membrane furnished with four areas. First or internal base produced before the proximal about one-quarter its length. Apex distinctly placed above apex of second. Third segment of posterior tarsi as long as second. Type Salda polita." loscytus j)olitns Uhler 1877. Uhler, Bui. U. S. G. G. Surv., Ill, p. 441, 1877. "Elliptical, highly polished, jet-black, very indistinctly punctate; the whole upper surface set with erect, remote, brown hairs. Head from above short, vertical in front and a little decurving, dull black, densely and irregularly scabrous and rugulose, the raised margin of the clypeus and the tylus ferruginous or pale piceous. Rostrum pale piceous, reach- ing between the intermediate cox^; base of vertex a little convex, formed into a distinct neck, contracted on the occiput; eyes very prominent, brown, placed obliquely. Antennae setulose, moderately long, stout, the two apical joints about as stout as the basal one; basal joint short, blackish-piceous, paler above; second joint much shorter than the two apical ones united, pale piceous or dull yellow; two apical joints dusky black, subfusiform, subequal in length, but much longer than the basal one. Pronotum subtrapezoidal, transverse, short, highly polished; the callosities forming the anterior lobe very convex, not reaching the sides, with a large, indented point in the center ; the posterior lobe much shorter, arched, higher than the anterior one, deeply concave, the humeral angles long, broad, and flat, subtruncated, with an oblong tubercle near the outer angle; the impressed line around the callosities very deep-seated, punc- tate; lateral submargins broadly flattened, rugulose, the edge recurved, decurving anteriorly. Pleural pieces dull black, obsoletely and minutely punctate; the prosternum very short, scarcely covering the base of the cox«. Coxas black; femora dull yellow or ferruginous, the under side of the anterior pair piceous; tibise dull yellow, their tips, the tarsi, and nails piceous. Scutellum moderately convex, obsoletely scabrous at base; the apical portion a little less prominent than the base, and the depression between them shallow; the surface faintly rugulose. Hemelytra flat, ferruginous, the clavus dusky black, and the costal area jet-black, polished, hungerford: aquatic hemiptera. 77 the whole surface minutely scabrous; the costal margin moderately arcuated, a little broadly and almost unifoi-mly reflexed; membrane very long, pale dull yellowish, somewhat clouded basally, the nervules piceous, long and almost straight. Venter black, highly polished, minutely punc- tate and pubescent; the genital segment and sometimes the posterior edges of the others testaceous. The costal margin is testaceous in two specimens, in which the black of that area is much reduced and limited to the posterior portion, inwardly. "Length to tip of membrane, 4% -5% mm. Width of base of pronotum, 1^-1% mm. "From San Diego, Cal. Kindly sent to me for examination by Dr. Hagen from Museum of Comparative Zoology." — Uhler. Also reported from Arizona. loscytus politus var. flavicosta Reuter 1912. Renter, Of. Finska Vet. Soc. Forh. Ill, Afd. A, No. 12, p. 21, 1912. "Specimens from Utah a half smaller than the type of polita from California. The costal area of corium and embolium black, while in the type example the entire corium, with the exception of the outermost point, rust-red and embolium yellow." Genus LAMPRACANTHIA Reuter 1912. "Head (brachypterous form) as broad as base of pronotum, sub- vertical. Eyes strongly exserted, distant from apex of pronotum. Ros- trum reaching to base or apex of posterior coxae. Pronotum shiny, strongly narrowed toward apex, marked by an apical stricture, poste- riorly terminated by a punctate impressed line. Sides sinuate, posterior angles prominent. Sulcus terminating callos posteriorly marked with im- pressed points and longitudinal wrinkles placed far behind the middle. Hemelytra most shiny. Abdomen of brachypterous form a little pro- duced, oval, convex, toward side and apex decurvate, clavus distinct, but corium and membrane coriaceous, merging into one. Veins wanting, or most obsolete. Embolium narrow deplanate. Type Salda crassicornis." — Uhler. Reuter thinks S. anthracina Uhler "Ohne zweifel zur dersel- ben Gattungen gehort." Lavipy'acanthia crassicornis Uhler 1877. Uhler, Bui. U. S. G. G. Siirv., Ill, p. 438, 1877. "Still more slender than the S. anthracina, brassy-black, very highly polished, the upper surface with black erect pubescence. "Head long, anteriorly oblique, moderately long and narrow, the eyes very obliquely prominent; vertex a little rugulose, the front dull, some- what shagreened and flattened; the tylus a little prominent, cylindrical, highly polished; the throat concave. Antennae short, stout, the basal joint short, stout, black, yellow at tip; the second joint yellow, about as long as the third and fourth united, much more slender than either of the others, a very little thicker at tip; third joint much thicker, both third and fourth joints subfusiform, black, more conspicuously hairy, equally thick, much longer than the basal one, the last a little longer than the preceding. Rostrum reaching to the tip of the posterior coxae, rufo- piceous, paler at tip. Pronotum sub-campanulate, long and narrow, with the disk much elevated, very convex, occupying all the surface excepting the very narrow posterior lobe, twice indented in the center, bounded behind and each side by a deep, transverse, coarsely punctate line, the posterior lobe consisting of only a slightly elevated linear tablet on the posterior margin, the margin proper moderately concave, the angles produced, acute; the sides deeply decurved, with the edge narrowly recurved, thinning out anteriorly, and bending down at the anterior end; the anterior margin truncate; the submargin with an impressed, punc- 78 THE UNIVERSITY SCIENCE BULLETIN. tate line. Scutellum strongly elevated at base, a little rugulose, deeply depressed on the middle and posteriorly. Legs and coxae bright yellow, the femora faintly tinged with brown, and the tips of tibiae and tarsi piceous. Venter black, minutely pubescent, the apex a little tinged with piceous. Corium and membrane coalescing, both coriaceous, long and narrow, convexly arched, deflexed on the sides, the part representing the membrane running off to an oblique rounded tip, with the nervures almost effaced. "Length to tip of venter, 4% mm.; to end of hemelytra, 4% mm. Width of base of pronotum, 1^/4 mm. One specimen from the vicinity of the Saskatchewan river, collected by Robert Kennicott. "This is surely only the dimorph of the form with perfectly developed membrane. In the S*. anthracina parallel forms occur, the one with a distinct membrane and the other with the membrane thickened and almost as coriaceous as the corium proper; also, the bounding nervure is faint and almost obliterated, almost the same as in this form of S. crassi- cornis, "In the present specimen, the nervules of the membrane are very in- distinct."—[7/ •a o X B Body Widths. Htnd Leg. Middle Leg. Fore Leg. Stagr. •5 e: S-B b: =^3 h: 3 =! 5- ^ -^ H ? p H ■^i' TO 5) CO -' Et ^ B So p T 2 t» 3 C- . 5- ■ a • fo ■ 3 ear n pro- X ...... . ear n meta- X 3 -a 1st instar .... 4.6 1.4 1.5 2. 1. 1.75 15 .8 1.38 1.2 .55 1.4 1.25 2d iustar 5 5 1.66 2. 2. '(5 1.5 ; 2 2 2.1 1. 1.8 1.6 .75 1.75 1.5 3d instar 8. 2.1 1. £.6 3.4 1.75 : !.9 2.7 1.4 2.5 2. .9 2A 1.85 4th instar .... 11 5 3. 1.47 4. 6.2 2.35 '■ 5.95 3.5 1.75 3.5 2.75 1.25 3. 2.5 5th instar .... 17. 3,75 1.75 5.95 9. 3.25 .. 5.5 2.5 5. 3.75 1.75 3.5 3.4 Summary. This common water bug is found in the trash of stagnant waters where it preys upon other aquatic animals. They winter as adults in the mud or trash of the pool. In the spring they mate and the female places from 65 to 158 eggs upon the back of the male, which is forced thus to carry them for a week or two till the young come forth. Six or seven weeks are required to complete a generation. Genus LETHOCERUS. Mayr. 1852. Most of the biological notes in the literature which deal with these insects are given under the generic names of Belostoma or Amorgius, Belostoma americana being a favorite. There are five species belonging to North America north of Mexico. L. americanus Leidy, L. obscurus Duf., angustipes Mayr, L. uhleri Montd, and L. annulipes H. S. Of these L. annulipes and L. angustipes are listed as western. The others general. No complete life history has been recorded for any of these giant water bugs. The notes that havej been made concerning these large bugs are sometimes difficult to assign to this genus without the possibility that the observer was watching Benacus. Habitat. Uhler says americanus lives in quiet, fresh or brackish waters. It prefers larger bodies of water] however than the little Belo- stoma, which may be found in very restricted pools. Hibernation. We are indebted to L. O. Howard, 1900, for the record that L. americanus winters as an adult. It was found in water under the ice. The temperature of the water was 10° F. The adult Belostomatid was taken alive by H. J. Giddings, of Sabula, Iowa, in February. Oviposition. In 1876, Dr. Riley read a paper before the American Association for the Advancement of Science, "On the Curious Eggmass of Corydalus coruutus (Linn) and on the eggs which have hitherto been referred to that species." "In this he surmised," says Weed, "that the HUNGERFORD: AQUATIC HEMIPTERA. 149 supposed eggs of Corydalus figured in the Am. Entomologist, 1868, really belonged to Belostoma granclis." Weed, while collecting on the edge of a pond near Lansing, Mich., July 3, 1882, found a mass of eggs beneath a board lying at the water's edge. "They looked fresh and beside them was a living B. americanus." In Weed's "Life Histories of American Insects," .1897, he says: "The eggs of the American Belostoma are deposited on pieces of wood or reeds along the margins of ponds, apparently where they will be wet, but generally not directly in the water. They are laid in clusters with from 40 to 60 or more eggs in each. The eggs themselves are' about one-fifth of an inch long, oblong, ovate in form, with the general color brown, spotted with black; they are lighter colored below than above, and there is a whitish crescent near the top with a distinct black spot at its apex. This crescent indicates the margins of a little cap which comes off when the young bugs hatch. Green, 1901, figures and describes eggs of Amargius indicus, and Distant, 1903, egg laying of same species. Feeding Habits. There can be no doubt of the fierce predaceousness of these bugs. Marie Merian, 1726, figures the nymph of a giant water bug sucking the juices from a young frog. Weed records that, "In the breeding ponds of the Massachusetts Fish Commissioners these bugs destroyed so many young fish that the authorities had to take special pains to catch and kill them." Matheson in Ento. News, 1907, trans- mits a letter from Philip Lawrence telling of an attack upon a wood- pecker. A woodpecker (an ordinary flicker) was heard to utter cries of distress, and fluttered and fell down out of a tree. A very large bug was found attached to the woodpecker's head. Its beak was inserted in the back part of the woodpecker's head and its legs clamped tightly around the bird's beak. Britton, 1911, records L. americamis as cap- turing a young banded pickerel, Lucius AmeHcanits Gmelin, measuring 8% inches long. The writer has found that these bugs will, in the laboratory, make out on pond snails if there be no other fare. Behavior. The fact that these bugs are to be taken at the electric lights, sometimes far from water, indicates that they are strong fliers, and that they do their migrating fi-om pond to pond at night. DESCRIPTION OF STAGES. Egg. Weed gives the egg of L. americanus as about one-fifth inch long, oblong ovate in form, with the general color brown spotted with black, lighter below than above, and a whitish crescent near the top, with a distinct black spot at its apex. The writer has captured Lethocerus uhleri and secured egg clusters in the aquarium. One female taken in July laid 4 clusters of eggs one night, 7, 7, 6, and 3 in each cluster, the eggs of which were bound together by a clear, gelatinous material. These eggs are figured on plate XVII and from them may be given this description : Size. Length, 3.25 mm. to 3.75 mm.; greatest diameter, 1.75 mm. to 2.25 mm. Shape. Newly laid, irregular ovoid. 150 THE UNIVERSITY SCIENCE BULLETIN. C0I07: Newly laid, pale, grayish green, the outer end of egg blotched with patches of darker color due to a trace of brown. The surface minutely and irregularly hexagonally reticulate, not plainly visible even under low power binocular, but becomes apparent under low power com- pound. A bit of the chorion mounted on a slide and examined by trans- mitted light shows a series of irregular hexagonal figures of various sizes. The boundaries of the figures appearing as a tracery of fine white or transparent lines on a brown ground. The egg clusters are held together and to their support by irregularly globose masses of gelatinous like material. See plate XVII. Summary. These giant water bugs, distinguishable by the presence of a groove in fore femora, are fiercely predaceous creatures of our larger ponds. In their nocturnal migrations from one body of water to another they are frequently attracted to the lights. The eggs of L. americanus and of L. uhleri are now known. In nature they are laid on reeds above the surface of the water. Nothing is known about the length of the various stages. Genus BENACUS. Stal. 1861. There is the one species in this country, B. griseus Say. It is the larg- est of our electric-light bugs. It differs from Lethocerus in having less thickened fore femora which are not grooved to receive the tibiae when flexed. The biological notes of any extent (aside from collecting) consist of two papers; one by Brimley, Ent. Neivs, 1905, describing the walking of B. griseus, and the other by Needham, Ent. News, 1907. This second paper is a splendid paper, accompanied by remarkably clear photographs of the egg cluster, hatching eggs, newly* emerged nymph and adult. Oviposition. Weed, 1897, tells us eggs are laid in masses on sticks and other rubbish at margin of ponds. Needham, 1907, says that "the egg clusters are two or three inches long, and contain 75 to 100 eggs of a size that for insects is fairly immense. The eggs are attached by one end in more or less regular rows, and they cover in a single layer the broader, flatter side of the stem. They would be conspicuous but for their resemblance in color to the stem." The longitudinal streaking of brown upon a lighter ground, together with the way they are placed and spaced, makes them fall into line with the flutings of the stem, and greatly as- sist in the concealment of the cluster. The egg clusters are attached above the water line. The Egg. (Description from Needham.) Size. 5 mm. long; 2 mm. in greatest diameter. Shape. Oblong oval in form with very obtuse ends. Color. Each egg is marked longitudinally with 20 or more irregular stripes of brown (often interrupted, cleft, fenestrate, or anastomosing, and always with uneven margins) convergent toward the center of the free end upon the upper side. Under a lens the eggs remind one of a pile of Georgia watermelons. If the color were green instead of brown hungerford: aquatic hemiptera. 151 the resemblances would be perfect. Not only is the shape the same, the "blossom end" being plainly suggested, and the exposed upper side being slightly more convex than the lower, but the streakings fade out below in a very similar manner. However, a closer inspection reveals a different feature at each end. At the free end, just below the "blossom scar," there is an obliquely-placed white crescent, whose arms extend down upon the sides and mark out the cap that the young Benacus will later push off at hatching. The brown lines of the under surface stop short at the edge of this crescent; they are still more abbreviated at the opposite end of the egg. At the basal end the egg is broadly capped with uniform dark brown. Incubation. Complete period not determined. Dr. Needham found a cluster June 13. It began hatching the 23rd. Hatching. Dr. Needham secured a splendid photograph of the little bug emerging from the shell. They came out of the egg by lifting a de- tachable cap of the shell. "The embryo lies once folded within the shell, its head flexed upon its breast, and its beak and legs extended flat against the venter of the abdomen. Thus the dorsum of the prothorax abuts against the detachable crescentic groove. The eyes appear before hatch- ing as black spots upon the arms of this crescent. The back is almost invariably downward, as seen in the figure, though sometimes turned a little to one side. On account of the obliquity of the pale crescent and the constant position of the embryo in relation to it, these eggs might readily be oriented for section cutting in embryology." "The thin lateral margins of the abdomen unrolling at hatching, and the legs becoming extended, the fledgling at once assumes proportions seemingly wholly incompatible with the size of the egg from which it came." Family NEPID^ Latr. 1802. Lati-eille, Hist. Nat. Crust. Ins., Ill, p. 252 (Neparife). A. Taxonomy of Nepid^e. Family Characteristics. Interesting v/ater bugs, distinguished from all others by the presence of long, slender caudal filaments which are not retractile. The fore legs are raptorial. The middle and hind legs very little adapted for swimming. The tarsi are 1-segmented. The beak is short and S-segmented. The antennae are concealed and ocelli are absent. The wings are reticulately veined. Three genera in America north of Mexico, Nepa, Curicta, and Ranatra. Only the last genus named is credited with more than one species. It is given seven by Van Duzee. Histo7ncal Review. These strange-appearing bugs were among the first aquatics to be noted in the literature. Frisch, 1727, describes and figures both a Nepa and a Ranatra under the following names: "Von der breiten Wasser Wanze mit den zwen Fang-Klauen und der hintern Lufftrohre" and "Von der grossen schmalen Wasser-Wanze mit der Fang fussen und der hintern lufftrohre." This author says that Johnston and Franc Rhedi had mentioned these bugs. Swammerdam 152 THE UNIVERSITY SCIENCE BULLETIN. figures Ranatra and Nepa and discusses them under the title of "The Flying Water Scorpion." Thus from an early date we have biological notes on Ranatra, Nepa, Notovecta and Naucoris. KEY TO GENERA. A. Body broadly oval and flat; legs not extremely, long and slender; prothorax much broader than the head; anterior femora but little longer than tibiae. Nepa. AA. Body elongate oval; legs not extremely long and slender; pro- thorax little broader than head; anterior femora considerably longer than tibiae. Curicta. AAA. Body very elongate; legs long and slender; prothorax narrower than head; anterior femora considerably longer than tibiae. Ranatra. Genus NEPA Linn. 1758. Body of these bugs is very flat and broad, nearly truncate in front, but pointed behind. The srhall head is set deeply into the anterior border of the prothorax. The eyes are small but protuberant. Ocelli are lack- ing. The prothorax is much wider than the head, and roundly incised in front to receive the head. The wings are broad and the limbs short. The front femora being little longer than the tibiae. Nepa apiculata Uhl. 1862. Uhler ill Harris Treat. Ins. InJ. Veg. edn., 3, p. 12, pi. 1, fi?. 1. The following description is taken from the Standard Nat. Hist., vol. 11, p. 253, 1884: "Color dull fuscous grey, with the base of the abdomen above more or less tinged with reddish. It is of an elliptical form, blunt in front, with a ridged middle line on the vertex, and with three short raised lines on the prothorax, each side of a longer one on the middle. The sur- face and margins of the thorax and head are roughly granulated, while these, together with the scutellum and corium, are rough and closely covered with stiff, short pile. The anterior femora have no teeth on the inner angle, but instead there is a prominent elbow, forming a wide ex- pansion for the sides of the deep gutter. The wings are smoke brown, with darker veins. This species closely resembles the European one, and measures about two-thirds of an inch to the end of the abdomen; while the respiratory tubes are a little more than one-fourth of an inch in length. Montandon has shown the differences between our species and the European N. cinerea Linn." Curicta howardi, Montd. 1910. Montandon, Bui. Soc. Sei. Bucarest, XVIII, p. 181. 1910. "Of form elongate oval, visibly attenuate in front and behind, lateral edges not subparallel, its greater width situated toward the posterior third. Head quite enlarged, although a little narrower than the front part of the pronotum, as Icng as wide, including the eyes, longitudinally carinate throughout its length, the carina more obtuse on the posterior interocular portion. Interocular space more than three times as wide as the diameter of the eye. Eyes little, globular, anterior part of the head triangular, exceeding the anterior level of the eyes by a length equal to its width between the eyes in front. "Pronotum very visibly longer than its width behind, lateral edges sub- parallel on their anterior three-fifths, quite strongly widened on their posterior two-fifths; with four obtuse longitudinal carinas, little accen- hungerford: aquatic hemiptera. 153 tuated and subparallel, two each side on the anterior part, the posterior part with two oblique carin^e arising from the anterior median carina and quite divergent behind. The anterior depression of the pronotum largely semicircular, with the anterior angles quite narrowed, in almost right angles, subacute. "Scutum with three longitudinal carinae, the median continuing quite plainly clear to the apex of the scutum, the two lateral slightly di- verging behind, vanishing on the middle of the sides of the scutum, which are slightly sinuate before the end. "Coria insensibly and gradually widened behind on their basal halves, giving their greatest width behind the middle and narrowing thereafter; membrane well developed, regularly subrounded at the extremity. Com- missure of the clavus almost twice longer than the scutum. "Appendages short, quite robust toward the base, attenuated there- after, about half the length of the abdomen. "Anterior femora quite robust, as long as the pronotum on its lateral edges, with a single median tooth easily visible on the inner edge of the groove where the folded-up tibia is lodged, this tooth is very visibly closer to the base than the apex of the femur; the external side of the groove appears also denticulate, as if notched on the basal third of the femur. Neither teeth nor sinuosities toward the apex of the femur. "Anterior coxae half the length of their femora. Anterior tibia quite long, blackish, with a pale annulation toward the base and the apical thirds likewise pale; the extremity of the tarsi come to the basal third of the femur when the tibia is folded back against the latter. "Intermediate and posterior legs short, the end of the posterior femora, which are a little shorter than their tibise, do not reach the suture of the last abdominal segment. Intermediate tibije a third shorter than their femora. Intermediate and posterior tarsi with their claws less than half as long as their tibiae. "Median longitudinal part of the prosternum slightly saddle-backed, projecting in all its width, more elevated than the lateral pieces, a little flattened and traversed its whole length by a fine median groove; very obtusely tuberculate in its anterior part. "A greater space between the intermediate coxae (hanches) than the anterior or posterior coxae. "Length, 19 mm.; maximum width a little behind the middle of the corium, 4.5 mm.; at base of the pronotum, 3.8 mm.; length of appen- dages, 7.7 mm. "Victoria, Tex., a single specimen, U. S. N. M." Genus RANATRA Fabr. 1790. The bugs of this genus are long and very slender, resembling^the sticks and trash amongst which they lurk in the water. The body is cylindrical and elongate. The head small and triangular and the beak short. The eyes are prominent. The prothorax is elongate cylindrical, and not as wide as the width across the eyes. The fore legs are rap- torial, with the femur much longer than the tibiae. The middle and hind limbs are slender and long, and serve it well in creeping about in the submerged trash or vegetation. Van Duzee lists seven species for America north of Mexico. One of these, Ranatra grisea Bueno, has no description and is only a manuscript name. It appeared in Bueno's list of Heteroptera in Smith's Insects of New Jersey, 1910. On the other hand, Van Duzee places kirkaldyi Bueno as a synonym of R. fusca, and Mr. Bueno assures me it is a good species. The descrip- tion in literature is unsatisfactorily brief. 154 THE UNIVERSITY SCIENCE BULLETIN. Montandon says that R. annulipes is synonymous with R. fabHcii Guer, overlooking the dates in the matter. However, as the writer stated in the beginning, the responsibility for these matters rests with Van Duzee whom he has faithfully followed. Ranatra americana is the commonest one of these insects in the United States, says Montandon. In spite of the careful notes of com- parison made by the above-named writer, it is not possible to prepare a satisfactory key without carefully examining much material. The writer would refer his Ranatras to Bueno for determination. Ranatra fusca. P. B. 1805. Palisot-Beauvois, Ins. Rec. Afr. Am., p. 235. "Greenish fuscous, setae shorter than the body, wings reddish fuscous." Bueno says this latter character is quite noticeable and adds "that the anterior femora are narrow, smooth, save for the middle tooth; that R. fvsca can further be differentiated from R. quadridentata by the much longer legs, the tarsal claws reaching nearly to the extremity of the air tube and the extremities of the femora of the third pair of legs attaining to the end of thie penultimate abdominal segments; by the prominent eyes; by the prothorax being slimmer and longer and unisulcate beneath. Ranatra kirkaldyi Bueno 1905. Bueno, Can. Ent., XXXVII, p. 187. "Abdominis dorsum orange brown; eyes small, not very prominent; prothorax much constricted at the middle, bisulcate beneath; wings smoky; anterior femora bi-oad, with a prominent tooth near the middle, otherwise smooth; posterior tarsi extending beyond the middle of the air tube; air tube shorter than the length of the abdomen; legs banded; length from tip of abdomen to tip of rostrum, male 23 mm.; 26.4 mm.; female, 27-31 mm." Ranatra nigra H. S. 1853. Herri ch-Schseffer, Wanz., Ins. IX, p. 32. 1853. Montandon, Bui. Soc. Sci. Bucarest, XIX, p. 64. 1910. Montandon makes the following remarks regarding this species: "Size almost of R. linearis; darker; eyes no larger but more project- ing; vertex broader; structure of thorax and length of legs as in R. elongata. I know of no North American species with legs as developed as those of R. elongata Fabr. The posterior femora of which extend back- ward plainly surpassing the last abdominal suture." He concludes that it could not be confused with other species of North America. Ranatra americana Montd. 1910. Montandon, Bui. Soc. Sci. Bucarest, XIX, p. 65. "This is the species most common and widespread in a great part of North America, at least in the east and southern part of the United States. My collection possesses examples from Lowell, Mass., Pittsburgh, Pa., Long Island, N. Y., Lake Forest, 111., and Florida. It has been confused probablv by the maiority of authors with R. quadridentata Stal., with which it differs in the size, being a little more robust (forte), in the form of the eyes, which are a little larger, more promment and plainly transverse, as broad as the interocular space, which is also hungerford: aquatic hemiptera. 155 more convex than with the true R. quadridentata Stal., the cheeks sen- sibly more elongated and more prominent in front of the eyes, subparallel, a little attenuated in front, but not divergent at the summit, better applied against the tylus, M^hich surpasses it, also very sensibly in front, w^hich gives to the anterior part of the head a form a little more elongate in front of the eyes. "Pronotum very visivly narrow^ed in the middle, enlarging insensibly in the rear and in front. This character permits one to distinguish quite easily this form from the true R. quadridentata Stal., with which the median constriction of the pronotum is a great deal less marked (assuse) and the anterior part more cylindrical. "The majority of the examples of this species have the double tooth at the extremity of the anterior femur, which has confused it with the true R. quadridentata Stal.; but this double tooth is often very attenu- ated and sometimes even altogether atrophied. I have distinguished this latter example under the name of R. americamis var. edentula. It is represented in my collection by two single female examples, one from Pennsylvania, and the other from Texas." Bueno, in his "Three Ranatras of N. E. U. S.," states that the legs of R. quadridentata are not unduly long, the tarsal claws of the third pair barely going beyond the middle of the air tubes, and the extremity of the femora going but little beyond the anterior margin of the penultimate abdominal segment. The eyes moderately large and the prothorax more stoutly built and bisulcate beneath. Ranatra brevicollis Montd. 1910. Montd. Bui. Soc. Sco. Bucarest, XVIII, p. 184. "It is indeed regrettable that I have described this new form from one unfortunately unique specimen, very little dissimilar, at first sight, from R. quadridentata Stal., but its specific characters do not permit it to be confused with the other species, fusca or quadridentata, from which it differs by its anterior femora being very slightly sinuate toward their extremities. It also has a single tooth before the median sinus of the femur. A little more thick-set, of form less elongate than R. fusca Pall de B., which would bring it closer to R. quadridentata Stal. It is sep- arated as plainly from this latter form by the much shorter form of the pronotum. In fact, the insect is 34 mm. long, of which length the .head and pronotum have only 10 mm. The appendages of 22 mm. are sen- sibly shorter than the abdomen. The intermediate and short posterior femora, folded forward, scarcely surpass the head. "The pronotum very robust, about a third as long as the abdomen, quite strongly dilated in front, and very strongly enlarged behind, does not allow confusion with R. kirkaldyi T. B. It is, besides, marked by two longitudinal grooves, slightly oblique on the sides, behind the anterior dilation, not attaining behind the transverse grooves which limit in front the posterior dilated part of the pronotum. This latter marked by a longitudinal median carina disappearing behind, less emphasized in front, where it traverses the transverse groove which limits the posterior dilated part. "The legs are very slender, a little shorter proportionally than those of R. quadridentata Stal.; femora reddish, marked by pale, wide, little visible annulations. "Metasternum in a plate (metasternal plate) terminated in the middle behind by a narrowed prolongation between the posterior coxse, appear- ing more elevated than in R. fusca P. de B. and R. quadridentata Stal., but less, however, than in R. fahricii Guer. -annulipes Stal. "This species, however, is distinguished from the three other known 156 THE UNIVERSITY SCIENCE BULLETIN. forms of North America by the genital opercule extending a little under the base of the appendages. The ventral segment which precedes the genital opercule almost straight on its longitudinal summit, very little convex before the extremity. "The interocular space convex between the eyes, but without trace of tubercle, scarcely wider than one eye. The eyes very slightly transverse, San Diego, Cal., coll. Coquillet, U. S. N. M,, Washington. Ranatra jyrotensa Montd. 1910. Montandon Bui. Soc. Sci. Bucarest, XVIII, p. 185. "Almost of the same size as R. fusca and R quadridentata ; length, 36.5 mm., of which 12.5 mm. are for the head and pronotum together, and 24 mm. for the abdomen; appendages quite robust, much shorter than the abdomen, 18.8 not altogether 19 mm.; intermediate and posterior femora quite long, 16 to 17 mm. (They are spread out at the sides in the speci- men examined, but brought back behind the posterior one attain the last abdominal suture.) "Eyes visibly transverse, as wide as the interocular part which is not regularly convex, but very obtusely elevated in the middle, as for the base of a tubercle. Cheeks converging in front, fitting most closely at the extremity against the tylus, regularly narrowed, not protuberant, the tylus slightly surpassing them in front. This character of cheeks attenuate and converging in front distinguishes this insect from all other North American forms in which the cheeks project, almost diverging at the apex of each side of the tylus. "Anterior femora quite slender, but scarcely a fifth as long as their coxae, without trace of tooth or sinuosity near the extremity, and with the median tooth of the lower inner side very little elevated, obtuse and little distinct. The anterior coxae almost as long as the pronotum on the side; coxae and femur together scarcely longer than the intermediate or posterior femora; anterior tibia very short, scarcely a little more than a third of the length of the femur. "Metasternal plate a little convex, well prolonged behind where it is lost between the posterior coxse with the first abdominal segment which resembles in the middle a fissure, narrowed at the extremity of the metasternum, all as elevated as the plate. "Memes cories," with membrane covering up the suture of the last abdominal segment, as in the other American species. Pronotum quite dilated in front, not much more dilated behind than in front, feebly carinate on the anterior part. The prosternum is hollowed out in all its width clear to the middle of its length; the bottom of the hollow is flat without groove behind the coxse, the lateral sides elevated, vanishing behind. "The specimen, unfortunately unique, is pale yellowish ochre; the intermediate and posterior femora with some vague clearer annulations." Long Island, New York, U. S. N. M., Washington. "This species has a little of the appearance of R. brevicauda Montand. of South America, but in this latter the cheeks are projecting; almost diverging at the summit of each side of the tylus; the genital opercule surpasses sensibly the extremity of the abdomen and the more robust appendages are also proportionally shorter; but it has almost the same form of vertex; by contrast, the anterior femur has a median tooth indeed stronger on the lower inner side and the lower outer side, also has an obtuse prominence at the place where the end of the anterior tarsus comes when the tibia is folded back against the femur, and farther from the end of the femur than the lower inner tooth." hungerford: aquatic hemiptera. 157 Ranatra annulipes Stal. 1854. Of. Vet. Akad. Forh., XI, p. 241. B. Biology of Nepid^. General Notes. These water bugs are to be taken by raking the mud and trash out of the water. They swim but little, spending most of their time motionlessly awaiting the close approach of some unwary creature. Their raptorial fore legs are usually set before them, and are capable of striking forth with lightning rapidity. Once the insect or other little animal is caught in the vice-like grip there is little chance of escape. The broad flat Nejm is likely to be found in the mud or leaves at the edge of the pool, while the Ranatras may be taken in trash in waters of various depth. The flat, dirty, roughened coat of the former, and the long, slender shape of the latter give these bugs an aggressive resem- blance to mud and tangled trash respectively. When going through open water, the legs are moved alternately, making the gait, as Kirkaldy sug- gests, a paddle rather than a swim. Genus NEPA Linn. The one species in this country has a general distribution east of the Mississippi river. The writer has taken it at Ithaca, N. Y. Habitat. It is a mud-loving bug, and usually found in raking out mud and trash near the water's edge. Bueno (Can. Ent., XXXVII) says N. apiculata is found in shallow water, not much over two or three inches deep, concealed in the mud or in situations where grasses grow out of water clinging together. Hibernation. It winters as an adult, and has been taken in winter collecting. Mating. Roesel, 1755, said that Nepa remains paired two days and nights. Hewitt, 1906, figures and describes the mating of Nepa cinerea Oviposition. The peculiar eggs of these bugs bear seven filaments.* They are inserted in the tissues of decaying plants. These were figured many, many years ago by Swammerdam, 1737. Roesel, 1755, stated that they were dropped to the bottom. Geoffrey said the eggs were laid in the twigs of Scirpus or some other aquatic plant. Recently we have Wesenberg-Lund's statement, 1915, that the species of his country lays its eggs at night and he figures them in moss plants. Brocher, 1913, says their Nepa lays in April and can be found in October with eggs com- pletely formed ready to lay. The number of filaments he says are vari- able. "Authors have indicated seven, but the eggs which I have had the occasion to observe had eight or nine. The eggs are fixed in the skin of plants in or floating at the surface, only the filaments resting exteriorly." Hatching. Brocher says at the moment of hatching the anterior ex- tremity of the eggs is opened like a lid of a box and the larva comes forth. He figures the hatching process giving 6 figures. The larva * Our N. apieulata lays eggs bearing 11 filaments. 158 THE UNIVERSITY SCIENCE BULLETIN. lacks the siphon. De Geer said that the young come forth in the middle of the summer, the complete development taking two months. Number of Instars. We are indebted to Roesel, 1855, for figures of all five nymphal instars of the European bug. Food Habits. This bug does not pursue its prey to any great extent, but lies in wait for it. Its flat body enables it to float with more sta- bility on the surface film than its relative Ranatra. The photograph on plate V shows the result of placing two bugs in a deep aquarium with- out any trash for support. When the two bugs encountered each other at the surface the smaller Nepa won the fight. Wood, 1884, says its food is mostly the larvae of May flies and whirligig beetles. Kirkaldy, 1906, says they are seemingly content with Daphnia and Cyclops, but suck fish eggs, and even attack small fish and tadpoles. Behavior. Severin & Severin have studied the behavior of these in- sects somewhat, together with Ranatra. Nepa has interested biologists from an early date, for Mouffet, 1634, figured it. Frisch, 1728, also figured it. See plate IV. Description of Stages. The egg has been figured and described from Roesel's time to Brocher's. The nymph described by Roesel, 1746-'61; Burmeister, 1835; and Kirkaldy, 1911. Walter Dogs, 1908, gives some structural details in his "Metamorphose der Respirations organe Bel Nepa cinerea." The Egg. Brocher describes the egg of the European form as follows: Size. "2.5 mm. long. Color. "Whitish yellow. Rosette of filaments at the tip, number of these varies from 7 to 9." The writer has found as many as 11 well-developed ova in one female N. apiculata in July. On plate XVIII is a figure of one of these. The description follows: Egg of Nepa apiculata. Size. Length, 2.8 mm.; width, 1.35 mm.; length of filaments, .96 mm. to 1.05 mm.; diameter of the crown, .42 mm. Shaj)e. An elongate oval, irregular in outline; somewhat pointed at one end. The other end bearing on one of its slopes a crown of eleven slender filaments arranged in a circle. See the figure on plate XVIII. On one side near the pointed end and diagonally across from the center of the filamentous crown is a circular raised area. Color. Pale yellow; filaments whitish; the raised circular area dark. Genus RANATRA Fabr. We have here many more biological notes than for Nepa. Bueno has given us a fairly complete account of Ranatra quad7~ide7itata. In fact more has been written about the biology of this group of water bugs than any of the others. Aldrovandus, 1602, under the name of Tipula aquatica mentions it. Swammerdam calls it Scorpius aquaticus. Habitat. Found in the tangles of trash and vegetation in the water. Kirkaldy and Lucas both record that Ranatra is at home in the mud at HUNGERFORD: AQUATIC HEMIPTERA. 159 the bottom. Bueno says R. quadridentata frequents deep water, where it clings quite fast to the stems of rushes or grasses, with its air tube piercing the surface film. The writer has found this common enough in pools where weeds had lodged, and also upon the floating dead leaves and stalks of cattail, where they were basking in the sun and entirely dry. Hibernation. Bueno says that Ranatra winters as an adult and is sometimes found frozen in ponds. Marshall and Severin, 1904, note that they were found in mud at the bottom of pools or creeks in winter. This seems as good a place as any to record the splendid observations of Wessenberg-Lund "Uber die Respirationsverhaltnisse bei unter dem Eise uber winternden, luftatmenden Wasserinsekten, besonders der Wasser- kafer und Wasserwanzen (1910-'ll)." There is an English summary at the end of this interesting paper which is here quoted: "It is a well-known fact, that air-breathing insects, especially Dytiscidse, Hydroplnlidse and waterbugs hibernate beneath the ice. For several months these animals which, as far as we know, do not possess any other organ of respiration than the open metapneustic tracheal system, though totally excluded from the air, sustain life in the ice-covered lakes. Ob- servations through the ice as well as in ponds, from which the ice had been removed, show that the animals do not, like frogs, bury themselves in the mud, but at any rate, during the first winter months, are swimming about lively beneath the ice. "Now, it has been shown that water insects especially in the fall at night-fall, disappear from ponds with slight vegetation, where they often made their home in summer and have laid their eggs, now going in search of localities with rich vegetation, more especiallj'^ bubbling springs or ponds, where the beach is covered with green plants. Numerous observa- tions in nature further show that the green plants, especially during the first winter months, produce great quantities of oxygen. Like silvery bubbles the oxygen covers the plants and later on accumulates beneath the ice. According to experiments in the laboratory and observations in nature it may be supposed that this oxygen during the first part of the winter forms the respiration air of the animals. Later on, when the vegetation dies off, the production of oxygen decreases, and methane and carbonic acid accumulates beneath the ice, the bubbles will not suffice to meet the claims of respiration. In what manner then are the animals able to sustain life beneath the ice during the two or three last winter months? The present paper shows, that insects, which in summer die, when only for a few minutes or hours excluded from the air, in winter at a temperature near zero are quite able for months to support a total exclusion from air. When every possibility of getting air fit for breathing is excluded, it seems that the animals settle down in a winter sleep, or 'Kaltestarre,' in which respiration is extremely lowered. In our country this winter sleep principally takes place in the Fontinalis carpets, which cover the bottom of a great many ponds and small lakes. It has been supposed that respiration through the integument plays a much greater part than hitherto believed. It has been emphasized that the views and supposi- tions set forth in this paper should be subject to thorough experimental explorations in physiological laboratories." He saw an adult Ranatra swim under 3 cm. of ice; noted that other bugs also do this and also that the large fat bodies and small eggs coni- moniy noted in the fall are reversed in the spring. Mating. Bueno says that in mating the male is below and to one side of the female. The process as noted by the writer is a prolonged one. The sexes may be distinguished by the figures on plate XVIII. 160 THE UNIVERSITY SCIENCE BULLETIN. Oviposition. Wessenberg-Lund says that with Ranatras the eggs are laid in early morning. Fred Enoch, 1909, gives the most complete ac- count we have. His observations were upon R. liniaris: "Last week I had the pleasure of observing the female engaged in ovi- positing on a floating leaf of Alisma, the edges of which were tightly grasped by the second and third legs, while the first were held close to- gether, high up on a line with the body, which slanted down from the head at about an angle of 30 degrees, the head being an inch above the leaf. The ovipositor was extruded, and the tip pressed by a downward and forward movement into the leaf, until forced through, when it was partially withdrawn, opened, and an egg placed in the hole. The long lateral filaments sprung open as the ovipositor was withdrawn. She moved along a quarter of an inch, and the process of boring the hole repeated, the long respiratory tubes resting on the fork of the last laid, which was pressed home until the tip of the egg was just level with the surface of the leaf. The eggs are also laid in half decayed stems of Alisma, and sometimes, though not so frequently, in healthy green stems. I have several times bred Prestwichia aquatica Lubbock from eggs of Ranatra." The writer has not seen the process, though he has watched for it a number of times. He disturbed one in the act at Beebe Lake, July 11. Eggs were laid in large numbers in a pool on Six Mile Creek, near Ithaca, N. Y., during June. A visit to this pool June 4 found Ranatra eggs abundant on top of floating dead Typha, some of them showing the I'ed eye spots. The photographs on plate VII are of some of these. Pettit, 1902, gave some very good drawings of Ranatra eggs which he described. Incubation. Latreille said, "lis restent quinze jours au fond de I'eau." Kulgatz says R. linearis is in egg stage two weeks. Bueno gives two or three weeks for the incubation period. In one aquarium the writer found eggs deposited on May 11 hatched June 14. This was at Ithaca, N. Y. Hatching. Bueno says the young emerge through a round cap at the top, which bears the filaments. Brocher gives a similar brief account. In hatching the nymph casts a clear membrane, post-natal molt, which it leaves as a diaphanous mantle, crumpled into a shapeless mass, and clinging at its caudal end in the fissure of the shell. See plate XVIII. No hatching "burster" is discernible under high power binoculars. Holmes 1907, says "When one sees a Ranatra on emergence from the egg he can- not but be surprised that the young insect should have been inclosed in so small a receptacle. The body of the nymph is as broad as the egg and over twice as long." Number of Instars. There are five nymphal instars. Bueno reared one to the adult stage and found that the first instar lasted 8 to 14 days; the second 9 days; the third instar 7 days; the fourth instar 8 days; the fifth instar 8 days. "A total of 61 days from egg to adult." Fecundity. The writer believes that these bugs produce many eggs, because in one restricted pool where there were few Ranatra the eggs were very abundant. Food Habits. Here there is a long list of references dating to an early time. The food of the young, says Holmes, "consists chiefly of small hungerford: aquatic hemiptera. 161 swimming forms, chiefly small crustaceans and insects which come near the surface of the water. Like the adults, they are very efficient ene- mies of mosquito larvas. They do not pursue their prey, and seldom catch forms that keep close contact with solid objects. They are like so many traps set and respond to an impact upon the water." He observed one very young bug catch an Ostracod which closed up and escaped. Ormerod in the Ento., XI, p. 95, gives the economic side to the foraging of this bug. Record is made of its attack upon the spawn of fish. The only method of ridding the ponds was to drain them dry and restock with fish. Swammerdam's account still stands as a good one. "There is not perhaps in all the animal creation so outrageous or fierce a creature against those weaker than itself than the water scorpion. It destroys, like the wolf among sheep, twenty times as many as its hunger requires. I have often seen one of these when put into a basin of water in which were 30 or 40 of the worms of the middle Libella, which are at least as large as itself, destroy them all in a few minutes." Bueno has found that their food consists of those unwary insects that fall into the water. The writer thinks that much of their food consists of such May-fly nymphs * as clamber about in the same environment. These it captures as they swim by. Behavior. Holmes and Severin have studied the behavior of these insects. In Holmes' "Evolution of Animal Intelligence" are several notes. He finds it negative to light when first brought to light from the dark, but this soon gives way to a decided positive response. Bueno, 1903, published an interesting account of the stridulation of Ranatra. When one of these insects is lifted out of the water it often gives forth a peculiar squeaking sound. The writer has not found it very loud, and often the bug must be held to the ear to hear it at all. It resembles somewhat the hum of a muddauber wasp at its building. Bueno describes it as a "rasping, creaky chirp." This sound or chirp- ing is made by "holding the fore pair of legs in the same plane as the body, perfectly straight" and separated as far as the prothoracic shoulder will permit and then jerking these rigid limbs up and down. The sound- producing device is figured on plate XVIII. There is, on the inner face of the outer lobe of the prothorax surrounding the coxae, a stridular area as figured. A roughened spot on the coxa makes the rasp that completes the musical device. Kiritshenks in Rev. Russe Entom., X, p. 311, men- tions an interesting flight "en masse" of Ranatra linearis. DESCRIPTION OF STAGES. These are taken from Bueno and relate to Ranatra quadridentata. The Egg. Size. 3 mm. long; width, 1 mm.; appendages, 5 mm. Color. White at base, growing dark toward apex; when freshly de- posited, clear white. * Callibaetis and Blasturus, fov instance. 11 — Sci. Bui. — 1669 162 THE UNIVERSITY SCIENCE BULLETIN. Shape. Imperfectly oval, flattened at the upper end, from which arise two long thread-like processes, longer than the ovum, and thickened at the base, diminishing in thickness toward the apex. Markings. Surface of chorion thickly covered with irregularly cir- cular pits, in the middle of which is a point. The processes appear smooth. The writer has photographed an egg (see pi. VII), and adds the following description of them: Length, 2.86 mm.; greatest width, .86 mm. Filaments, basal, amber-colored part 1.35 mm.; the larger, opaque white part, 2.73 mm., the filament measuring a total of 4.1 mm. These filaments are placed at the cephalic end of the egg as shown in the drawing on plate XVIII. The filament is differentiated into two parts, a basal amber-colored part, and an outer, larger opaque white part. The basal part has a core of opaque white and a sheath of amber with the diameter of the cylinder uniform. The outer part is larger than the basal part, and tapers gradually to a point near the tip, where it again enlarges slightly. The tip is acutely rounded. The surface of the egg is finely but irregularly hexagonally reticulate, appearing punctate under low power. Surface is rough. Color is cream, at first light, darkening with age. Micropylar spot near fila- ments as shown in drawing. Clear, smooth and amber colored. The central spot very dark. This spot can be seen to be reticulate under certain lighting as can also the white part of the filaments. Here the reticulation is very fine. First Instar. 1 "Form in a general way resembles the adult. It is, however, broader in proportion to length. The head, including the eyes, is broader than long, excluding the rostrum. Each eye is less than one-third the width of the head, round and projecting beyond the thoracic margins. The thorax is a little under one-third the total length of the bug. It shows the three rings. "The rostrum is four-jointed, stout, the first joint stoutest, about twice as long as the second, and subequal to the third and fourth. The fourth or terminal joint is furnished with tactile hairs, as in the adult, the antennae are short, club-shaped, one-jointed, the extremity nearly as broad as the length, situated near the basal joint of the rostrum. The thorax is a little under one-third the total length of the bug, and shows the three rings. The bifid air-tube is absent, its place being taken by the blunt extension of the terminal abdominal segment, as described in connection with the respiratory system. The legs are comparatively stout, the second and third pairs being nearly as long as the entire bug. The tarsi of the first pair are one-jointed and entirely destitute of claws; those of the second and third pair are also one-jointed, armed with long claws. The tibise of these two pairs are armed with a comb-like row of stout spines going partly around at the distal end, at the tarsal joint, and are furnished with a few coarse hairs at this end also. The first pair of pedes is the counterpart of those of the adult, except that they are much broader in proportion, and do not show the blunt, so-called apical tooth in the femur. "Size: Long., 8 mm.; lat., 1 mm. at thorax; air-tube long., 1.5 mm. "Color: Brownish of varying shades, including the legs, which are banded with lighter rings. The eyes are black or dark brown. "Markings: None sufficiently definite to be called such. There is a lighter median line in the thorax." hungerford: aquatic hemiptera. 163 Second iTtstar. "Form as in the first stage, perhaps a little less broad in proportion to the length. Rostrum as before, except that it is perhaps a little less stout. Antennas still blunt, short and stout, but not so club-shaped. They now begin to show two equal joints. The legs as before, the first pair not quite so broad proportionally, with the blunt apical femoral tooth beginning to show as an undulation in the inner side of the femur. The tibiae of the second and third pair are better provided with spines, which increase in number distally. The terminal combs very apparent. "Size: Long., 13 mm.; lat. not measured, dimensions being taken from moulted skins. "Air-tube, 2.7 mm." Third Instar. "Form, not greatly changed from the preceding instars, except for slight variations in proportions. "Rostrum, much as before, but a little slimmer. In this instar the tactile hairs at the extremity of the proboscis are quite noticeable. "Antennae appear imperfectly three-jointed in this instar. The suture separating the basal joint is quite noticeable, and that between the second and third joints shows as an incision in the outer margin of the antennas, from which a little impressed line goes about half way across. Below and above this indentation are two prominences, the beginning of the lobes of the segments. Both prominences are ai'med with a stout spine, that of the third joint being about twice as thick as that of the second. The third joint appears to be pitted at the rounded end. "Thorax much narrower, distinctly trisegmentate. Head closer to the adult shape, the eyes flattened on the inner side, and quite prominent. The wing-pads first appear in this instar, though very small and rudimen- tary. "Legs and tarsi as before, with the spines of the second and third pair of tibi« stronger, and the tibial comb more developed. In this instar the fringing hairs of the second and third appear, scattered on the femora and sparse on the tibiae, but quite long. "The false stigmata are quite noticeable at the sides of the abdomen, as darkened spots in the integument. The legs are now shorter than the length of the bug, and reach but little beyond the extremity of the respira- tory tube. The first pair are not quite as broad proportionally as in the previous instars, and show the same undulations of the femora where the second tooth will be. "Size: Long, (extremity of the rostrum to end of siphon), 19 mm.; lat., 1.4 mm.; air-tube, long., 4 mm." Fourth lyistar. "Form as before. Rostrum but slightly changed. "Antennae evidently three-jointed, the prominences more developed, and the several spines on the third and second segments quite evident. "Legs and tarsi as before, with the peculiarities more accentuated. They extend only a litle beyond the siphon, and are therefore not as long as the body by the length of the thorax. "Colour more or less mottled, with banded legs. General tint grayish. "Size: Long., 30 mm.; lat. (not taken, specimen being only a cast skin in this instar) ; air-tube, long., 7 mm." Fifth Instar. "Form elongate as in the adult. Head, including eyes and exclusive of rostrum, broader than long. Rostrum as before, but nearer the adult shape. The second joint begins to show the basal constriction so notable in the adult. "The rostrum is shorter than the length of the head. Eyes trans- 164 THE UNIVERSITY SCIENCE BULLETIN. versely elongate, somewhat flattened on the inner margin, projecting beyond the expanded anterior portion of the prothorax. Antennae are still two-jointed, the basal joint extending into a process, nearly as stout as the terminal joint, and about three-fifths as long. The suture between the joints is very faint. The joints are now abundantly furnished with the tactile spines, which reach full development in the adult. Prothorax widened anteriorly by the sockets of the anterior pedes, gradually con- stricted towards middle, and expanding again basally, but not quite as broad as the anterior portion ; excavate for the insertion of the head and truncate posteriorly. Prosternum not sulcate, deeply excavate posteriorly. Mesothorax with long narrow wing-pads of the hemelytra, pointed pos- teriorly in the middle. Metathorax concealed. First abdominal segment • showing as a ring between the wing-pads of the posterior alae, which barely attain the extremity of the pads of the hemelytra. A straight suture marks off this segment from the next. The abdomen is more than twice the length of the thorax, the segment following the thorax slightly constricted. The sides of the abdomen are folded over itself, and are furnished with fringing hairs. There is an indentation in the edge at each segment that bears the thickening of the formative pseudo- stigmata. The abdomen has only six apparent segments and the siphon or air-tube. The false stigmata show in segments three to five, dorsally, as thickenings of the integument, darker than the surrounding skin. The siphon is jointed to the sixth segment, and freely movable. The abdomen is keeled beneath, the keel bearing a fringe of short hairs on each side, which meet those of the inflexed abdominal margin. The legs approach more closely to the adult. The second so-called tooth or prominence in the first pair is quite evident. The true tooth is large and triangular, and the clawless tarsus rests against it when the tibia is folded on the femur. The second and third pair are slender, ciliate, with globose coxas; the tarsus of the second pair does not quite reach and the second goes slightly beyond the end of the siphon. Both these are one-jointed, and armed with prominent curved double claws. "Size: Long., 44.4 mm. (from tip of rostrum to tip of siphon); lat., 2.9 mm. (at the thorax, but not at wing-pads). Siphon, long., 12.3 mm. "Colour: More or less luteous of varying degrees, without any special pattern. The legs, which in the preceding instars are banded, are ap- parently unicolorus in this. This, however, may be the peculiarity of the two individuals from which this description has been drawn up. The eyes are black and shining." Family NOTONECTID^ Leach 1815. Leach, Brewster's Edinbg. Encyc, IX, p. 124. A. Taxonomy of Notonectid^. Family Characteristics. Perfectly aquatic forms, differing from all others in the persistent habit of swimming on their backs. They are much deeper bodied than other Heteroptei'a which live in the water, and while being oval in form with the apex of the wing-covers conical, have the convexity of the surface above. Their eyes are large, reniform, twice sinuated on the outer side, and project a little way over the front margin of the prothorax. Ocelli are absent. Antennas 4-segmented, shorter than the head and partly concealed in depressions between the head and thorax. Rostrum 3- or 4-segmented. Hind limbs fringed for swimming (sometimes not conspicuous in museum specimens of Plea.) Tarsi 2- segmented (male of Anisops has one segmented tarsi on front limb.) Two tarsal claws present in all, but inconspicuous in the hind limbs of hungerford: aquatic hemiptera. 165 those with well-developed swimming fringes. Pronotum is transverse, moderately convex, and narrower in front than behind. The venter of the abdomen is equipped with a median longitudinal keel or carina and provided along the lateral margins with guard hairs for closing over the two longitudinal troughs, thus forming air channels. — From Uhler and Parshley. The family Notonectidse embraces, according to Kirkaldy, two sub- families: Pleinae and Notonectinse. In his "Revision of the Notonectidae, Part I," in Trans. Ent. Soc. London (3), vol. 35, p. 393-426, 1897, this author begins his systematic revision of the family. This is continued in a second paper which appeared in the "Wiener Entomologischen Zeitung" for 1904, and entitled "Uber Notonectiden." In the following year Bueno published "The genus Notonecta in Amer- ica North of Mexico." Kirkaldy lists six genera in the subfamily Notonectinse : Notonecta L. Ariisops Spin., Enithares Spin., Martarega B. White, and Nychia Stal. It is in his second paper that he erects the genus Buenoa which is allied to Anisops. In this country we have the three genera: Notonecta, Buenoa and Plea. These may be separated by the following: KEY TO GENERA. A. Legs are quite similar. Plea Leach. AA. Legs dissimilar, hind legs flattened and fringed for swimming. B. Last segment of antennae much shorter than the penultimate. Notonecta Linn. BB. Last segment of antennae longer than the penultimate. Buenoa Kirk. Of these three genera Notonecta is the commonest, being represented in this country by 12 species, the genus Buenoa comes next with 5, while the little Plea so far is credited in the literature with but one. Genus PLEA Leach. DESCRIPTION OF GENUS. "The thorax is obscurely hexagonal, with the hinder margin prominent and rounded; the head as broad as the broadest part of the thorax; the eyes are rather oblong, without the least tendency to converge behind; the hinder pair of legs not more ciliated'^ than the others, but are termi- nated by very strong and distinct claws; the tips of the elytra accumi- nated and entire." — Leach. One species so far listed for the United States, which is Plea striola Fieber. Kirkaldy, 1904, remarks: "Wahrscheinlich haben Uhler und champion zwei oder drei ai'ten hier vermischt." An examination of the material in various collections would suggest that we may have more than one species. Kirkaldy lists two genera in the subfamily Pleime — Plea and Helotr-ephes. To the first he ascribed 12 species, and to the lat- ter, 4 species. It is interesting to note that he considers the Plea minutis- sima of Leach and of Fieber under P leachi McGregor and Kirkaldy. * They are more ciliated in our own species. 166 THE UNIVERSITY SCIENCE BULLETIN. Plea striola Fieber, 1844. "Highly arched behind; wing covers pointed; forehead with brownish- red median stripe; eyes black; hind half of closing suture brown. From North America. "It is three-fourths lines long. Similar to the two preceding species, but noticeably narrowed and pointed behind. Grayish yellow. Over the front, a brownish-red median stripe. Eyes black. The entire dorsal sur- face is unflecked. The wing covers behind the suture are much higher arched than the other species. Posterior half of suture brown, darker at the margins. Legs yellowish, last tarsal segment brown at the tip. Femur dark brown at base. The sculpturing consists of an impressed point in the middle of the five or six covered reticulations clearly visible in the substance of the wing cover, a very short delicate seta arises from each puncture, which is visible only on close observation." — Fieber in Entomologische Monographien, 1844, pp. 18-19. Genus NOTONECTA L. "Head. Eyes not contiguous. Labrum attaining to about the middle of the second rostral segment. Last segment of antenna shorter than penultimate. "Thorax. Pronotum not very transverse. Alse present. Hemelytra divided into clavus, corium and membrane. Scutellum large and almost equal in length to the metanotum, except in N. mexicana, where it is only about half its length. Hind femora not attaining to the apex of hemely- tra. Posterior ambulacra practically contiguous. Intermediate am- bulcara not nearly contiguous. "Abdomen. Median ventral carina of the abdomen is thickly pilose, as are the lateral margins, thus forming a waterproof covered way over the 'gutters' which lie, one on each side of the carina, for the conveyance of air. The junctures of the connexival ventral segments are always covered with short thick hair, and the scutellum and hemelytra are generally clothed with short golden yellow pubescence. The sexes are almost indistinguishable in size, form, colour and general appearance, though, of course, the female, when full of mature ova, is dilated more than at other times. They can be readily separated by an examination of the last three or four abdominal ventral segments. These are horizontal in the female, rounded and anteriorly excavated in the male." Specific characters suitable for diagnosis are difficult to find. Kirk- aldy used head measurements. These were also employed by Bueno and are used in the following tables. Color does not furnish a reliable diagnostic character. Kirkaldy, in casting about for some specific char- acters, said: "Great hopes were entertained by me that the male genitalia would furnish a reliable diagnostic character, but in the few species {N. glauca, N. lutea, N. irrorata and N unduJata) , of which suitable material was available, these hopes have not been realized." The writer has examined the ovipositors of the females of most of the species in America and finds considerable specific difference in some. He is quite sure he could distinguish any one of the four species above men- tioned from one of the gonapophyses of the female, alone. Whether Dr. Kirkaldy studied them with the same care and discrimination that Dr. Harry Knight has used with the Miridae remains to be seen. hungerford: aquatic hemiptera. 167 KEY TO GENUS NOTONECTA LINN. Rearranged from Bueno's Notonecta of North America, 1905. A. Small species, subrobust. B. Vertex* twice or less than twice the synthlipsis.f C. Vertex 1^^ to 2 times the synthlipsis; width of pro- notum 1% times length; width of scutellum 1% times the length; length of insect 9.4 mm. to 11 mm. N. indica. CC. Vertex 2 times synthlipsis; width of pronotum 1% times its length; width of scutellum IVs times its length ; length of insect 10.2 mm. N. howardii. BB. Vertex more than twice the synthlipsis; vertex 2^/2 times synthlipsis; width of pronotum 2 times its length; width of scutellum IVs times its length; length of insect 10 mm. to 13 mm. N. undiilata. AA. Small, slender species. B. Vertex 3 times synthlipsis; width of pronotum 2 times its length; width of scutellum IVs times its length; length of insect 8.2 mm. to 10.2 mm. N. variabilis. BB. Vertex more than 3 times synthlipsis. C. Vertex 6 times synthlipsis; width of pronotum 1% times the length; width of scutellum IVi times the length ; length of insect 8 mm. to 8.8 mm. TV. raleighi. CC. Vertex 6 to 8 times synthlipsis; width of pronotum 1 % times its length ; width of scutellum 1 Va times its length; length of insect 10.7 mm to 12 mm. N. iihlef-i. AAA. Medium sized, robust species. B. Vertex at least 3 times synthlipsis. C. Vertex 3 to 41/2 times synthlipsis; width of pronotum 21/^ times its length; width of scutellum 1^/2 times its length; length of insect 11 mm. to 14 mm. N. mexicana. CC. Vertex 3 times synthlipsis; width of pronotum 2 times the length; width of scutellum IVt times its length; length of insect 12.1 mm. to 14.4 mm. N. irrorata. BB. Vertex less than 3 times the synthlipsis. C. Vertex 2 to 2^^ times the synthlipsis; width of pro- notum 2 times its length; width of scutellum IVs times its length; length of insect 12.1 mm. to 17 mm. N. lutea. * Vertex — distance between the eves at the front. t Synthlipsis — distance between the eyes at base of the head, at the most constricted part. 168 THE UNIVERSITY SCIENCE BULLETIN. AAA. Medium sized, robust species — concluded. CC. Vertex 2V^ times synthlipsis; width of pronotum 11/7 times its length; width of scutellum IVs times its length; length of insect 13.1 mm. to 14 mm. N. montezuma. BBB. Vertex not twice as wide as synthlipsis. C. Vertex 1% times synthlipsis; width of pronotum 1% times its length; width of scutellum 1% times its length; length of insect 8 mm. to 13 mm. N. shooterii. CC. Vertex but slightly wider than synthlipsis; width of pronotum 2 times its length; width of scutellum IV5 times its length ; length of insect 12.6 mm. to 15.5 mm. N. insulata. The following descriptions have been copied from Bueno, 1905. He used Kirkaldj's copy of descriptions, which appeared in his Revision of the Notonectidae, pt. 1, Trans. Ent. Soc. London, 1897, and added measure- ments, etc. I therefore credit them "Bueno and Kirkaldy." Notonecta indica Linne 1771. Linne, "Mantissa Plantorum," p. 534. "Head rather large, notocephalic lateral margins straight, not very divergent from the base; vertex varying from one and one half to twice as wide as synthlipsis. Scutellum rather shorter than in N. undulata Say. Hemelytra variable: (1) fulvous or dark stramineous, with a broad black fascia near the apex, occupying the basal two thirds of the membrane and the apex of the corium; (2) varying from bluish black to violet brown, the corial margins of the clavus and a broad irregular blotch about the middle of the corium, fulvous or dark stramineous. Otherwise like N. undidata Say. "Long., 9.4 to 11 mm.; lat., 3.4 to 3.6 mm. — Bueno and Kirkaldy. Distribution: Utah, Nevada, California, Arizona, Oregon and Texas. Bueno says that this bug is extremely abundant in Lake Texcoco, Mexico, where its ova, together with those of one or two Corixas, are used as food under the name "huantle." Notonecta howardii Buneo 1905. Bueno, Journ. N. Y. Ent. Soc, vol. 13, p. 151. "Notocephalic lateral margins of head curved; vertex twice as wide as synthlipsis; base of eyes about twice as wide as synthlipsis. Pronotum four-fifths broader than long, humeral and lateral margins sinuate. Scutellum one-fifth longer than wide, not concolorous. Hemelytra clouded with black going into smoky, and with a broad black band across the membrane and the apex of the .corium. Apex of the membrane smoky. Corium and clavus moderately clothed with a golden pubescence. Membrane lobes subequal. Pedes: Intermediate femoral spur small, rather blunt, concolorous. "Measurements: Vertex, 1 mm.; snythlipsis, 0.5 mm.; pronotum, lat., 3.5 mm., long., 1.9 mm.; scutellum, lat., 2.7 to 2.9 mm., long., 2.2 to 2.4 mm.; insect, long., 10.2 mm., lat. (pron.), 3.5 mm.; types. No. — , U. S. N. M. "Described from two specimens in the U. S. National Museum, col- lected by Dr. E. A. Mearns in Arizona." — Bueno and Kirkaldy. HUNGERFORD: AQUATIC HEMIPTERA. 169 Notonecta undulata Say 1832. Say, Disc. n. sp. Het. Hem. N. A. Fitch reprint, p. 813. Le Conte Ed. Comple. Writ. 1859, p. 368, vol. 1. "Head diverging curvedly (varying in degree) from the synthlipsis, which is not quite two and a half times less wide than the vertex. Pronotum very similar to that of N. glauca Linne, but the humeral margins as a rule not distinct. Scutellum not quite one-fourth shorter than the metanotum, varying in color from pale luteous to black, with divers intermediate arrangements of the two colors; similar hemelytrical markings occurring with dissimilarly colored scutella and vice versa. Metanotum varying from luteous to black, with three or more dark castaneous stripes; scutellar margin luteous. Hemelytra exceedingly variable, giving rise to a number of well-marked varieties, though these are linked together by intermediate forms. — Bueno and Kirkaldy. Distribution: General over United States — Kansas; Colorado; Mis- souri; Nebraska; Massachusetts; Rhode Island; New York; New Jersey; Maryland; Washington, D. C; Quebec, Canada; Illinois; Texas; Arizona; Idaho; Virginia; Iowa; Ohio; Tennessee; Indiana; Kentucky; Utah; Ontario; Maine; North Carolina; Florida; Louisiana; Minnesota; Mon- tana; New Mexico; California; Oregon; British Columbia; Vancouver Island; Manitoba; New Hampshire; Vermont and Connecticut. Notonecta variabilis Fieber 1851. Abh. Bohm. Ges. Wiss. (5), VII, p. 477 (in part). "Head, notocephalic lateral margins diverging curvedly from the nar- row base, vertex about three times as wide as synthlipsis. Pronotum, width of posterior margin not quite twice as great as the length of the pronotum. Hemelytra, clear white inclining to yellowish, with a golden pubescence. Alar nervures pale golden yellow. Pedes and abdomen as in N. inidulata Say. "Long., 8.2 to 10.2 mm.; lat., 3.2 to 3.7 mm." — Bueno and Kirkaldtj. Distribution: Kansas, Nebraska, Ohio, Michigan, Wisconsin, Rhode Island, Indiana, Maryland, Pennsylvania, Massachusetts, Illinois, New York, Quebec, Ontario, Maine, New Jersey, District of Columbia, North Carolina, Florida, Ohio, New Hampshire, Vermont and Connecticut. Notonecta raleighi Bueno 1907. Bueno, Can. Ent., vol. 39, p. 225. "Head: Notocephalic lateral margins nearly straight; vertex more than six times as wide as synthlipsis; base of eyes over four times as wide as synthlipsis. "Pronotum two-thirds broader than long; base and lateral margins nearly straight, humeral margin sinuate. Scutellum one-quarter broader than long, sides pronouncedly sinuate, caudal angle long. Hemelytra little longer than the body, moderately clothed with a silvery pubescence on the clavus and corium; membrane lobes unequal. Abdomen luteous, fringing ciliae black, sparse. Pedes luteous; intermediate femoral spur concolorous, long, thin and sharp. "Coloration: Eyes dark reddish-brown. Cranium and prothorax whitish. Scutellum ranges from pure light yellowish to black, disk margined with smoky orange-yellow on the hemelytral margins. Hemely- tra ranging from white with vague beginnings of the corial fasciae and black humeri with white membrane,' through all intergrades to a form with a blackish stripe along the anterior margin of the corium; black margins to the clavus along the scutellar edges; a blackish streak along the corium near to and parallel to the claval suture; black corial fasciae 170 THE UNIVERSITY SCIENCE BULLETIN. merging into the black membrane, which shades off into smoky and then white at the apex. One of the types is the most pronouncedly melanic specimen of the species in a series of 60 or so specimens. In this the extreme of scutellar darkness with orange-red edges obtains. The ex- ternal edges of the clavus are broadly black, shading into smoky to the corial suture; the dark band on the corium parallel to this suture is broad ; the humerus has a black streak running into the corium, which is dark luteous, except for the black fasciae which coalesce with the black membrane, which in turn lightens to smoky at the apex. The structural characters are the same as in the others. "Measurements. Vertex, 1 mm.; synthlipsis, 0.15 mm.; pronotum, long., 1.5 mm to 1.8 mm.; pronotum, lat. (at humeral angle), 2.5 mm. to 2.9 mm. (at base 2 mm.); scutellum, long., 1.6 mm.; scutellum, lat., 2 mm.; insect., long., 8 mm. to 8.8 mm.; insect, lat. (at humeral angle of pronotum), 2.5 to 2.9 mm. "Described from sixteen specimens from Raleigh, N. C. Types: Col- lections U. S. National Museum, American Museum of Natural History, C. S. Brimley, and mine. "This species very much resembles a dwarf variabilis, but it is easily distinguishable by the cephalic structure."- — Bueno. Distribution : Bueno gives it as locally abundant at Raleigh, N. C. He records it also from New Jersey, Illinois, Maryland and Washing- ton, D. C. Notonecta ithleri Kirk. 1897. Kirkaldy, Ann. Mag. Nat. Hist., (6), XX, p. 58. "Head: Notocephalon in the form of an inverted wine decanter, mar- gins greatly curved, widely diverging toward the vertex, which is six to eight times wider than the synthlipsis, at which point the eyes are almost contiguous; breadth of the eye about ten times as great as that of the synthlipsis. Pronotum : humeral angles acute, accentuated lateral margins sinuate, humeral margins little separate from the posterior mar- gin. Metanotum dark purple-brown. Hemelytra varying from dark brick-red to rich orange-yellow; a large irregular black blotch at the base of the corium extending transversely and nonacuminately from the apex of the clavus to the golden-yellow exocorial lateral submargin ; membrane dark red-brown, apically black — this tint encroaching more or less basally. Alar nervures brown. Pedes: Coxas blackish; intermediate tibial spur blunt, subcylindrical. Abdominis dorsum : first and second segments rufotestaceous, deeper marginally, the remainder flavotestaceous, lurid marginally; this latter tint encroaching more and more apically. Ab- dominis venter rufotestaceous, densely provided with greenish-black cilia." — Bueno and Kirkaldy. Distribution: New York, Massachusetts, Florida, New Jersey, Louisi- ana, and District of Columbia. This is a rare bug according to Bueno and the writer feels proud to have one specimen in his own collection — the gift of Mr. Bueno. Notonecta mexicana Amyot and Serville 1843. Aniyot et Serville, Hist. Nat. Ins. Hem., p. 453. pi. 8, fig. 7. "Head narrow at base, parallel for a short space, then sinuately di- verging; vertex from three and one-half to four and a half times as wide • as synthlipsis. Pronotum very transverse, about two and one-half times wider than long, lateral margins slightly sinuate, humeral margins gently and elongately curved, posterior margin not sinuate; humeral angles acute, accentuated. Metanotum not quite half as long again as scutellum, black (dark vars.) or violet brown margined luteous (pale vars.) Hemelytra varying in color, membrane lobes subequal. Alae hungerford: aquatic hemiptera. 171 semi-transparent, smoky, nervures brown (pale vars.), or semitrans- parent, smoky black, nervures blackish-brown (dark vars.">. Abdominis dorsum black (dark vars.), or rufoluteous with paler genital segments (pale vars.). Abdominis venter varying from black to testaceous. "Long., 11 to 14 mm.; lat., 4.5 to 4.8 mm." — Bueno and Kirkaldy. Bueno adds: "The shape of the head and the very transverse pronotum separate it very readily from the other species of the genus. In his revision, Kirk- aldy goes at length into the color variations, and since his remarks cover the ground exactly, I reproduce them here: 'The hemelytra are usually rich scarlet, vdth black membrane, but the latter hue often extends beyond the apical margins of the clavus and corium; the scarlet also varies much in shade, graduating in one direction to pale greenish-white through pale yellow, pale olive-green, deep yellow, orange, and pinlcish, and in the other through crimson and violet-red to deep violet-black, though in the last the sutures of the hemelytral divisions are usually narrowly violet-red ; in some specimens the apex of the corium is black, from the base of the membrane to the margins of the hemelytra in a straight line, and the rest of the hemelytra are rich crimson. The hemelytra are rarely maculate, occasionally the center of the clavocorial suture has a more or less pronounced black smudge about the center. It may be con- venient to propose the varietal names ceres for the pale-colored forms and. hades for the southern violet-black race. Herrich-Schaffer notes a variety with a large central ochreous stripe on the scutellum, while Fieber describes among the varieties with red hemelytra: (1) Schild schmut- ziggelb mit bramien grnud, and (2) Schild braun mit gelblichem rand' — these three varieties I have not seen. In the U. S. National Museum and Heidemann collections the specimens from Colorado Canon, Hot Springs and Catalina Mountains, Arizona, are var. hades, and above the average size and with more prominent eyes. In the National Museum there is a specimen from Mexico which has the scutellum with the yellowish base (or apex) mentioned by Fieber." Localities: Colorado, Arizona, California. Uhler gives its distribu- tion as "western states." Notonecta irrorata Uhler 1876. "Head small, notocephalic lateral margins diverging widely, vertex a little more than three times as wide as the synthlipsis; width of vertex and of the eye subequal ; eyes rather larger proportionally than in N. triguttata, etc. Pronotum much wider basally than apically, lateral margins not sinuate, humeral angles acute, humeral and posterior mar- gins sinuate. Hemelytra rich black, irrorated (especially on the clavus) with refulgent yellow brown, anterior lobe of membrane and apex of exterior lobe smoky. The irrorations vary greatly in different individ- uals; in some the corium and membrane are almost immaculate, in others the whole of the clavus and corium is irrorated, imparting a checkered appearance, while in others the clavus is rich (almost metallic) yellow- brown with faint, distant, narrow black lines. Alar nervures brown. Pedes: intermediate tibial spur small. Abdominsis dorsum: first to fifth segments black, sixth, seventh and eighth sordid grayish-brown. Ab- dominis venter black. "Long., 11.8 mm. to 14.4; lat., 3.6 to 4.7 mm." — Bueno and Kirkaldy. Localities: Illinois; Kentucky; Ohio; Tennessee; Montana; Quebec; Maryland; New York; Washington, D. C; Rhode Island; Indiana; New Jersey; Ontario; Maine, Massachusetts; Michigan; Florida; New Hamp- shire; and Connecticut. 172 THE UNIVERSITY SCIENCE BULLETIN. Notonecta lutea MuUer 1776. O. F. Muller, Zoologia Danise Prodromus, 1776. "Head large, notocephalic lateral margins slightly diverging from the base, vertex two to tvv^o and a quarter times as wide as synthlipsis. En- tirely luteous (except the dark claret eyes, occasional dark -brown mark- ings along the sutures of the clavus, etc., the bronze-brown sternal hair- tufts, the black unguiculi and venter). Scutellum a third wider than long. Exterior lobe of membrane about half the size of the interior lobe and obviously not so long. Alar nervures luteous. Pedes; spine on inter- mediate tibia large, acute, black-tipped. "Long., 13 to 17.1 mm.; lat., 4.5 to 5.5 mm." — Bueno and Kirkaldy. Localities: Bearfoot Mountains, B. C, North America. This is a Palearctic species noted for the first tim.e in this country by Bueno in the Ent. Neivs for June, 1904. Its former range in Europe is given as Lapland, Finland, where it is general but rare, Sweden, Bohemia and Austria. In Asia it is recorded for Siberia. Notonecta shooterii Uhler 1894. Uhler, Proc. Calif. Acad. Sci., 2d ser., vol. 4, p. 292. "Head short, notocephalic lateral margins slightly diverging from the base and slightly converging towards the vertex, which is about one-third larger than the synthlipsis. Pronotum large, rather longer in pro- portion to its width than in the other species, lateral and humeral mar- gins sinuate. Scutellum small, nearly one-third shorter than the meta- notum; black, base purple-brown. Sterna dull ivory-white, corium more or less concolorous, forming with the clavus a blotch of varying extent, and usually with a whitish spot along the apical margin, the claval and corial markings very similarly disposed to those of N. triguttata; apex of membrane, smoky. The hemelytra vary, however, very much, being quite violet black in some individuals (melsena, var. nov.), while in others they are concolorous pale luteous. Membrane lobes always subequal in ordinary forms; generally unequal in the leucochroic varieties (ochrothoe, var. nov.), and rarely subequal {tearca, var. nov.). Alar nervures I'ich brown. Pedes: intermediate coxae black, tibial spur small, rather blunt. Abdominis dorsum: segments 1 black, 2-5 violet-brown (the fifth apically black), 6 blackish, genital segments greenish-testaceous, all the segments more or less dull blackish laterally. Venter varying from green to black, carina and cilia black." "Long., 8 to 13 mm.; lat. pron., 4 to 4.7 mm." — Bueno and Kirkaldy. Localities: California, Mexico and Central America. Notonecta montezuma Kirkaldy 1897. Kirkaldj-, Tr. Ent. Soc. London, 1897, p. 402. "Head narrow at base, similar to that of N. mexicana, notocephalic lateral margins fairly straight, diverging from the base, vertex two and a half to three times as wide as synthlipsis. Hemelytra orange-red, suffused (especially marginally) with crimson, and sparingly and irregu- larly marked with black; membrane bluish-black, apex brownish-black, lobes subequal. Pedes: coxae brownish-black, intermediate tibial spur, small, rather blunt. Abdominis dorsum : segment 1 black, 2 sordid testa- ceous, suffused with crimson and margin with black. Venter black. "Long., 13.1 to 14 mm.; lat., 4,7 to 5 mm." — Bueno and Kirkaldy. Localities: California, Mexico. A rare species, only two specimens in collections, according to Bueno. The type is from Mexico. hungerford: aquatic hemiptera. 173 Notonecta insulata Kirby 1837. W. Kirby in Richardson's Fauna Boreali Americana Insects (Reprint in Can. Ent. 1878). "Head; notocephalic latei'al margins fairly straight and nearly par- allel, very slightly constricted near the base; vertex little wider than synthlipsis, which is about one-fourth less than the width of the base of the eye. Lateral and humeral margins of the pronotum sinuate. Scutel- lum varying slightly in length, but occasionally reaching and usually nearly reaching the base of the metanotum, black (Fieber in .V. rugosa records two varieties {coridgera and basalis) with yellowish scutellum, but I have not seen them) . Hemelytra variable in pattern and color . Alae, basal nervures crimson, the others yellow-brown. Pedes: 00X86 black, intermediate tibial spur small, slender, not tipped with black. Abdominis dorsum: segments 1 black, 2-6 brilliant scarlet, 7-8 reddish- testaceous. Abdominis venter black, connexivum and central carina green. "Long., 12.6 to 15.5 mm.; lat., 4.8 to 5.6 mm." — Bueno and Kirkaldy, Localities: Nebraska, Colorado, Arizona, New Mexico, New Jersey, Nevada, Connecticut, Indiana, Utah, Maine, Oregon, California, Quebec, Ontario, Massachusetts, New York, Montana, Dakota, Idaho, Vancouver Island, New Hampshire and Rhode Island. Genus BUENO^Kirkaldy. Named in honor of Mr. J. T. de la Torre Bueno. Similar to the genus Anisops, but the male is provided with two tarsal segments on the front legs, and the claws are differently formed. Head: Eyes not contiguous, but interior margins about parallel, their margins curving slightly, making distance at vertex greatest, and inter- ocular space long and narrow. Labrum reaching to apex of second rostral segment; last segment of antenna longer than the penultimate. Thorax: Pronotum not most transverse; alae present and the hemely- tra divided into clavus, corium and membrane, and more transparent and hyaline than in Notonecta. Hind femora not reaching apex of hemely- tra. The hind tarsi are provided with more conspicuous claws than Notonecta. The middle and front legs are armed with long spines and the males of Buenoa elegans and Biienoa, margaritacea at least are equipped on the front leg with a tibial structure borne on the inner face of a prominence, which is forced into a thin elongate spur by the eleva- tion of the inner angle or margin of the tibia near its base. Tarsi of front legs 2-segmented in both sexes. Abdomen : The abdomen is provided with a median ventral carina and the lateral margins of the venter are provided with guard hairs which cover the "gutters." The female has the last ventral abdominal seg- ments modified for sheathing the ovipositor, which consists in the main of a pair of somewhat spatulate chitinized gonapophyses for placing the eggs in the tissues of plants. KEY TO THE SPECIES OF GENUS BUENOA. A. Species over 6 mm. long. B. Pronotum in the male with four depressions, appearing tri- carinate in this sex. 174 THE UNIVERSITY SCIENCE BULLETIN. A. Species over 6 mm. long — conchided. C. Head, including the large eyes, nearly as wide as the pronotum in the male, a little narrower in the female. Body robust; legs stout, interocular space not very nar- row behind. Length, 7.5 to 9 mm. B. carinata Champ. CC. Head, including the large, somewhat flattened eyes, dis- tinctly narrower than the pronotum in both sexes; legs rather slender, and, like the greater part of the body, pale in color. Length, 6.5 mm. B. albida Champ. BB. Pronotum almost unimpressed^ though lateral carinte are well marked in some males. Length, 6.7-8.1 mm. B. margaritacea Bueno. AA. Species less than 6 mm. long. B. Eyes large and prominent; shape slender. B. 2ylutycnemis Fieb. BB. Eyes large, but not prominent; shape more convex. B. elegaiis Fieb. The above table is adapted from Champion and from Bueno to sepa- rate the species given in Van Duzee. Kirkaldy evidently did not recog- nize either of Champion's species, for he says of B. albida Champ. "Wahrscheinlich mit A. platycnemis identisch" and A. carinatus Champ, he makes a synonym of his own B. antigone. The writer has been in- terested in providing a- means of determining the bugs which he may meet in his biological studies. He feels that such guides should have been provided by those best acquainted with the groups, but where no keys are available he has improvised them from the literature and such ma- terial as has been authoritatively identified for him by such workers as Bueno, Barber, Gibson, Parshley, etc. If the keys include synonyms and false statements the reader is referred to Van Duzee's Catalogue and to the descriptive literature. The writer wishes most heartily that there were more papers dealing with the taxonomy of the aquatics, such as those of Uhler, of Bueno, and of Barber. Bnenoa carinata Champion. 1901. Biologia Centrali Americana, vol. 2, p. 372, 1901. "Elongate, robust, smooth, shining; head and pronotum sordid white, the color of the latter modified by that of the mesonotum showing through; the scutellum usually black in front and rufo-testaceous or testaceous behind, sometimes entirely pale; the elytra sordid white, the colour modified by that of the metanotum and the apex of the abdomen showing through, these parts being usually black and the rest of the upper surface rufo-testaceous or testaceous; the under surface, antennae, and legs testaceous, the venter black, the terminal segment and some spots on the connexivum excepted, the posterior femora beneath, and sometimes the anterior and intermediate tibiae externally, each with a dark streak down the middle. Head (with the large eyes) nearly as wide as the pronotum in the male, a" little narrower in the female; interocular space not quite twice as wide on the vertex as at the base, considerably narrowed beneath, the vertex sulcate down the middle. Pronotum about as long as the scutellum in the male, slightly shorter hungerford: aquatic hemiptera. 175 in the female; the disc in the male with two broad elongate depressions towards the middle and a very large subtriangular depression on each side, these latter almost enclosing an oblique oval elevation behind; the spaces between the depressions appearing raised and forming three longitudinal ridges. Legs stout, the four anterior tibi£e much widened, the anterior pair in the male angularly dilated on the lower edge at the base beneath, and also wider than in the female. "Length 7.5 to 9; breadth 2.25 to 2.5 mm." Localities: Florida, New Mexico and California. Buenoa albida Champion 1901. Biologia Centrali Americana, vol. 2, p. 373, 1901. "Elongate, narrow, rather slender, smooth, shining; sordid white, the scutellum more or less rufo-testaceous, the legs, antennte, and under sur- face pale testaceous ; the abdomen above testaceous, with transverse black bands, beneath black, with the median carina and some marks on the connexival segments pale testaceous. Head (with the eyes) narrower than the pronotum in both sexes; interocular space about twice as wide on the vertex as at the base, the vertex sulcate down the middle. Pro- notum (along the median line) about as long as the scutellum; the disc in the male with two elongate deep depressions towards the middle and a very large subtriangular shallow depression on each side, thus appear- ing tricarinate in this sex. Legs rather slender; the anterior tibiae in the male angularly dilated on the lower edge at the base, and also con- siderablv widened. "Length 6.5, breadth, 1.875 mm." Localities: Texas, (Mexico). Buenoa margaritacea Bueno 1908. G W. Kirkaldy, in his "Uber Notonectiden," gives a short descrip- tion in German of a species measuring 6.7 to 8.1 mm. in length and 2 to 2.3 mm. broad, which he says is the commonest North American species. The following is his description of this bug which he considered to be Buenoa platy,cnemis (Fieber) 1852: "Ventral carina pale. Pronotum of male and female not, or not clearly, carinated. Hind femur with some 100 bristles. Front tibia as long as the tarsus and claws together, first tarsal segment a half longer than the second, this twice as long as the somewhat pointed finger-shaped claw. Middle tibia a little longer than the tarsus, first tarsal segment tvnce as long as the second, which is double as long as the talon-shaped claws." Bueno, in Journ. N. Y. Ent. Soc. X, p. 236, also describes this bug under Anisops platycnemis but subsequently (1909, Journ. N. Y. Ent. Soc, XVII, pp. lA-11) recognizes it as a new species, to which he gives the name Buenoa margaritacea. Bueno in Jl. N. Y. Ent. Soc, vol. X, gives the following: "Head rather large, with prominent eyes, notocephalic lateral mar- gins slightly diverging from synthlipsis and again converging toward the vertex; to the naked eye, the notocephalon appears of equal width throughout. Pronotum overlapping base of head somewhat pointedly, and terminating in a point at the meeting of the hemelytra. Metanotum completely covered by the hemelytra. Hemelytra pearly, histrous, vary- ing in color when closed from pure white through a bluish to a blackish tinge; in this respect resembling strongly the shadings of mother-of- pearl. Alar nervures pale; alse hyaline. Abdominis dorsum, varying 176 THE UNIVERSITY SCIENCE BULLETIN. from testaceous base and blackish tip to nearly entirely black. Venter black. Pedes testaceous. "Length, 6.7 to 8.1 mm.; lat., 2 to 2.3 mm." Localities: Kansas, New York, New Jersey, Illinois, Florida, Ver- mont and Massachusetts. Buenoa platycnemis Fieber 1851. Rynchotographilla, 1851, p. 61 (described under genus A7iisops). "Dirty white. Eyes large. Connexivum narrow, whitish-yellow. Ven- ter black, sides yellowish with three-cornered black median flecks. Hemelytra with black margins (Randrippe.) Scutum black, with margin and tip yellowish. Scutellum ochre-yellowish, brown at base. Menta- notum black. Metanotum ochre-yellowish with brown median stripe. From America, Porto Rico and St. Thomas. Length, 2V^ lines. Dirty white. Posterior margin of pronotum above the scutellum scarcely over- lapping. The color of the pronotum (Schildes) varies; it is either black, with narrow or broad pale margin, or ochre-yellowish with the base brown. Hind back varies in color, as above mentioned. Dorsal segments blackish brown, next to last and the base of the last, dirty white. Front tibia very broad at base, on one side broadened out into a lobe, in the male a broader tooth toward the base. Front and middle femora on the inside and above, sides of the metathorax, blackish. Appendage of femur with a black spot." — Fieber. Localities: New York, New Jersey, District of Columbia, Illinois, Texas, California. Buenoa elegans Fieber 1851. Rhynchotographilen, 1851, pp. 61-62. "Milky white. Antennje black. Hemelytra without closing suture (Schlussnath.) Membrane with four-cornered black transverse fleck. Metanotum white. Abdomen black. From America. Length, 2% lines. "Head somewhat broader than pronotum, whose posterior margin is gently projecting. Fore edge projecting angularly. Front elongated, truncated and narrowed in front. Labrum longish. Third segment of beak above and fourth entirely black. Margin blackish brown. Hemelytra very finely haired. Breast yellowish. Abdomen black, three basal seg- ments of connexivum with yellowish white posterior margin. Fore tarsi somewhat shorter than the tibiae, appearing thickened on the inner side at the base with a saffron yellow finely indented wart. Fore and middle tibi« with a brown median stripe (apparently formed by the dried inner margins of the groove touching.) Margin of parapleura fringed with blackish brown. Foremargin of hind femur brownish transparent. Ap- pendages of femur with a brovraish spot. Middle tibia, above on the basal half brownish. Abdomen yellowish. Dorsal segments black, three of these with white median spots at base. Clavus without a trace of a suture fused with the corium. Anus dirty whitish, margin narrowly whitish yellow. Membrane with large, almost elongate, four-cornered blackish-brown opal colored iridescent transverse spot, extending from the outer basal angle to the inner margin." "Observation: Described by Blanchard and Brulle as Notonecta nivea in the Hist. Not. Tom., 3, p. 88, as follows: "Body of a somewhat moonlight color, short and somewhat convex, head and corselet of a dirty white without spots. Wings white, very transparent, entirely deprived of spots, legs and abdomen of a grayish yellow. Length, 3 to 4 lines." "It appears that Brulle had two species before him, which do not agree with the above description, but may belong to A. productus." Localities: Maine, New York and New Jersey. hungerford: aquatic hemiptera. 177 B. Biology of the Notonectid^. General Notes. Of all our American water bugs none are more gen- erally known in their native haunts than the back-swimmers. They are to be found in nearly every pool and pond, and afford most interesting objects for aquarium study. The fact that they swim on their backs readily distinguishes them from all other water bugs. Some of them spend much of their time hanging, back downward, just beneath the surface film, the tip of the abdomen in contact with the sur- face, the body, head downward, at such an angle that just the claws of the intermediate limbs may touch the surface and the hind limbs directed well forward of right angles to the body poised for a sudden rowing stroke. This, in fact, pictures our best known, and most widely dis- tributed Notonecta undulata. Others prefer to float submerged in open water or cling to the shelter and shade of aquatic vegetation. The predatory tendencies and daring attacks of these insects upon other animals of formidable size have been known from the first bio- logical notes concerning them. Records of the capture of fish and various insects, mature and immature, by members of the genus Notonecta are common. However, the intimate ecological connection of these insects with the life of the pool lies in the fact that a large part of the food of the young of all of them, and the adults of Buenoa and Plea, consists of Ostracods and other small Entomostraca. The adults of all the species observed in this country pass the winter, either hidden in the mud and other debris of the pool or remain more or less active, as conditions may permit. They have been observed swim- ming beneath the ice in spring-fed pools in midwinter. Mating occurs beneath the water in spring, and the females deposit their white oblong-oval eggs, either attaching them by means of a water- proof glue to the surface of sticks and brush in the water, as in the case of most members of the genus Notonecta, or inserting them in the tissues of water plants and the like, as in the case of Plea, Buenoa, and Noto- necta irrorata. There are one or more generations, depending upon the species and the climate. The details of life history and behavior are treated under the notes concerning the various species. Biological Notes on Plea striola. Aside from a few notes on habitat, little has been written regarding the biology of our tiny back-swimmer. This little fellow has been taken in tangles of aquatic vegetation, such as Elodea, Chara and the like, in widely separated parts of our country. Van Duzee lists it as occurring in the following states: Kansas, New York, New Jersey, Florida, Illi- nois, Texas, Iowa, Massachusetts and California. Even the suggestion concerning its feeding habit which has crept into a recent text on aquatic biology — information taken from a pub- lished inference to be sure — is erronous. The author of the suggestion that Plea apparently subsisted upon the juices of the plants, based it 12 — Sci. Bui. — 1669 178 THE UNIVERSITY SCIENCE BULLETIN. upon the fact that they were never seen to prey upon the little Crustacea present nor were these forms depleted in numbers appreciably. The writer has had them under close observation many times and has frequently seen them catch and devour Ostracods and other small Crustacea. The process has been observed under binoculars and differs little from that of any other back-swimmer. The prey is grasped by the fore limbs and the victim rolled about until the stylets locate a vul- nerable point. Several small creatures have been captured and destroyed one after another by some Pleas under observation. Their relation, then, to the aquatic complex of life is that of a consumer of small crustacean creatures that abound in the same shelter of the submerged vegetation. They do spend much time clinging closely to the plant filaments, and when they leave it they go clipping off in a manner indicative of a definite goal. Their locomotion is even and rapid, but the journeys not extended, for they are content, as a rule, to dodge from the shelter of one stem to another. Their hind limbs are not heavily fringed, as is the case with the other genera, and their gait through the water an even scoot, rather than the jerky motion of the others, which use only their hind limbs in strong propelling strokes.* The writer has read that the hind wings do not exist and that the front ones are united into one. According to this, their distribution would be restricted to perma- nent pools to which they had been carried, as adults, attached to transported mats of aquatic vegetation, or perhaps entangled in mud upon the feet of birds or beasts, or as eggs upon or within their sup- porting plant growth. However, the writer wonders if a few may not be found which have functional flying wings, for of two specimens placed in a glass tumbler in which the water was one-half inch from the top, one disappeared over night. A study of many specimens shows that the fore wings are not united along the median line. They meet and interlock by a device figured on plate XXV. The hind wings are always represented by distinct pads as shown in the figure on plate XXV. Sometimes these pads are of fair size, and until a very full series has been examined, the writer does not believe it can be said that they may not occasionally possess truly functional wings. A genus of Corixids was once described as having hind wings aborted, but among them the writer has found well- developed flying wings, a point confirmed by Dr. Abbott, who created the genus. The egg stage has not heretofore been observed. The writer brought in a number of Plea from the field station on July 17, and placed them in an aquarium with Elodea and Chara. Their eggs were inserted in the tissues of the plants as shown on plate XXV. A description of the egg follows : * Wefelsheid records a diurnal migration from 2 meters from shore in day time to near the bank in evening. hungerfo'rd: aquatic hemiptera. 179 The Egg. Size. Length, .598 mm.; diameter, .234 mm. Color. Very pale greenish. Shape. Elongate oval, but not regular. Viewed laterally the top line is nearly straight, while the lower line is curved. The anterior pole is flattened on the side bearing the micropyle, which is a slightly curved, cylindrical peg. The surface appears reticulated with irregular hexa- gons when seen under compound microscope. Most of our knowledge of these curious little back-swimmers comes from Heinrich Wefelscheid's paper, "Uber die Biologie und Anatomie von Plea viinutissima Leach," 1912. This writer made an extended study of the above species. He says it winters as an adult. That the female is larger than the male and that mating begins in May and reaches its height in early June. He figures a mating pair, and states that they may remain in copula as long as two hours. Eggs were found in the laboratory in decaying stems of "Ra- nunculus aquatiles." They were placed in the stem with the long axis parallel with that of stem, which agrees with our observation on Plea striola. Egg stage lasted three or four weeks, and the five larval stages took one and a half months. He says only one generation possible, though Kulgatz says apparently two. As to the life of the adult he remarks: "Die Imago kann mindestens noch ein zweites Mai uber win- tern und sich fortpflanzen." He found them preying upon Daphnians, and said they lived a week without food (most any predator will do this), and adds "Sie satzen dann meistens in den Blattescheln oder on den Stenglen und sangten offenbar die Pflanzen safte ein." In regard to its power to fly, he states "Dennoch scheint es mir nach dem verhaltnismassig kraftigen Bau der Flugel nicht sweifelhaft zu sein, dass das Tier, ebenso wie seine nahe verwandte N. glauca, noch die Fahigkeit des Fliegens besitzt." He notes also that in the British Mu- seum there is an example from Batavia taken at electric light. They are capable of making sounds under water and he reports finding "Reibleisten" on the sternum of the mesothorax "mit Hilfe deren das geriiusch wohl erzeugt wird," and finds a tympanal organ in the meso- thorax, as in Corixa. The remainder of his paper is devoted to many interesting structural studies which he has made. His paper is a doctorate dissertation and shows how much there is to be done with our own species. Genus NOTONECTA L. BIOLOGY. At the close of his "Revision of Notonectidse, Part I," Kirkaldy stated : "I had hoped to give an account in this paper of the metamorphoses of N. glauca L. Unfortunately my attempts of rearing this species from the ova during two seasons have been only partially successful. I have, how- ever, reared three larval instars from ova deposited in captivity, and am aware of two more, so that Notonecta has at least five larval instars. "In the ultimate and perhaps also the penultimate larval stage, the species can always be determined by the structure of the head; in the first three, however, the shape of the head and eyes does not resemble the 180 THE UNIVERSITY SCIENCE BULLETIN. adult at all, but is more akin to that of Corixa, and the entire form of the insect in these stages is very different from that of the adult." The above was written in 1897. Little more has been added since that time, due to the difficulty of keeping the nymphs alive under laboratory conditions. Bueno, 1905, reported his failure to get them beyond the second or third instar. Hoppe, 1912, in his paper on "Die Atmung von Notonecta glauca," makes a few remarks on the life history, noting five nymphal instars. The writer, 1917, published an account of the biology of Notonecta xmdulata, and during the year 1917 was able to study the biology of three other species, N. variabilis, N. insulata, and N. irorata, which are found in the waters about Ithaca, N. Y. The experience gained in studying the behavior of N. iindidata was found useful in bringing these species through their transformations. The behavior of the back-swimmers, especially vdth reference to respiration, has been quite fully treated, though even here there are problems as yet unsolved. Brocher, 1909 and 1913, and Hoppe, 1912, have made extended studies on the respiration of N. glauca and Christine Essenberg, 1915, of Berke- ley, Cal., has written upon the behavior of four California species. ECOLOGY. The members of this genus have been made the object of an ecological study by Bueno, who presented his notes in his "Notonecta of North America." He says in substance that N. undulata hangs from the sur- face almost constantly and its raptorial claws can be seen forming little elevations as it hangs head down. N. insulata seems to prefer to float in clear spaces in clear cold pools, about midway between the bottom and surface. "On the other hand, N. irrorata and N. uhleri appear to like to hide among the roots of plants growing at the water's edge, to which they cling. The former may at other times also be seen floating below the surface, in the shadow cast by bank or fallen tree or broken branch. The habits of N. vanahilis diff'er somewhat from the others, since this bug prefers to lurk among the water weeds at the bottom." Oviposition. Until recently there seemed to be a distinction between the manner of oviposition of the common European species and our American forms, the common glanca of Europe placing its eggs in the tisues of plants, as noted by Regembart in 1875, and our American species affixing them to the surface of plants, as noted by Bueno and Essenberg. The writer reviewed the question in the "Egg-laying habits of Buenoa margaritacea" at which time he supposed all American species placed their eggs upon the plants. In a footnote to his paper recording the "Life History of Notonecta xmdulata," he recorded the fact that N. irrorata places her eggs in plant tissues even better than N. glauca. In another paper appearing in the Entomological News "Concerning the oviposition of Notonecta," the writer presented the evidence as to the manner of oviposition of the various members of the genus, basing this evidence upon the study of the female ovipositors. The plates submitted with this paper are here reproduced to indicate the interesting study hungerford: aquatic hemiptera. 181 which they present concerning form and function. The following species were studied and figured: N. lutea, N. raleighi, N. undulata, N. varia- bilis, N. insxdata, N. glauca, N. mexicana, N. shooteni, N irrorata, N. uhleri, and N. indica. Sufficient material of N. undxilata, N. variabilis, N. insulata and TV. irrorata were examined to indicate that the ovipositors of these may possess specific differences. Kirkaldy long ago gave up the idea of distinguishing the males by their genetalia, but it would be worth while to look into this matter again. N. glauca, N. lutea, N. irrorata have long ovipositors and place their eggs in plant tissues. The others merely affix them to the surface, at- taching them there by means of a colorless, water-proof glue. See plates XIX, XXI and XXII with accompanying legends. Migrations. These insects habitually fly from their winter quarters to their breeding grounds in spring, as has been noted long ago. There are some very interesting notes on the migration of back-swimmers, one so curious that it is reproduced in substance here: "In evening twilight of a pleasant September day, 1846, Sir Geo. Simpson encamped for the night, on his route from Red river to the head- waters of the Mississippi, in the vicinity of latitude 48" north and longi- tude 95° or 96° west. While supper was preparing he perceived some- thing falling on his hat like drops of rain ; and as there were no clouds to be seen, presumed that it could not be rain. On looking on the ground near the fire he saw that the falling objects were winged insects, which, although unable to fly, had life and motion. The number rapidly in- creased so as to give great annoyance, and continued till the ground was covered by the shower. On the following morning Sir George found that this shower extended from 25 to 30 miles in the direction he was travel- ing. No information as to its extent other directions. It was ob- served that soon after the shower the weather changed from warm to cold. It is therefore probable that the whole of this immense swarm of insects encountered the cold current, and were paralyzed and precipi- tated thereby. They all died soon after falling. In no instance were they seen to revive after coming into a warmer atmosphere." — Amer. Journal of Science and Arts for November, 18U7. The above appeared in American Journal of Science and Arts for November, 1847, by Prof. Forrest Shephard. It relates to the same mi- gration that was mentioned by the writer in his quotation from S. G. Simpson in a former paper. Means of Defense. All collectors, from Frisch, 1728, to present day, testify to the stinging propensities of uncautiously handled back-swim- mers. If handled carelessly, they pierce one with the stylets of their beak, the burning, painful sensation of which may last for some time. Doctors Riley and Johannsen considered it of sufficient importance to figure the salivary apparatus of Notonecta in their "Hand Book of Medical Entomology." Some species, N. variabilis, for instance, secrete, when handled, a milky fluid which oozes from the sides of the thorax beneath the wings and at the base of the so-called coxal plates. This fluid reminds one of a similar secretion of Gyrinids. Enemies. Predators as they are, their lives are in constant peril. The newly hatched are eaten by their older brothers. Woe betide the 182 THE UNIVERSITY SCIENCE BULLETIN. helpless nymph caught by a hungry neighbor while disengaging himself from the integument of an abandoned instar. Other water bugs of his size and larger, with predatory tendencies, water beetles, etc., are his enemies. Needham figures a nymphal dragon fly in the process of de- vouring an unfortunate back-swimmer. In the matter of parasites, he is burdened with the usual Hydrachnid mites, and a tiny wasp parasitizes its eggs From the larger forms of life the back-swimmers enjoy considerable measure of immunity. Seldom, indeed, have they been taken in the stomach contents of fishes and the like. Little wonder that they are a dominant form of pond life. The abundance of back-swimmers and boatmen in the same pool has been difficult to understand until recent investigations into the habits of these two types have cleared up the question. Notonecta insulata. This large back-swimmer compares favorably with N. irrorata in size, yet even its largest varieties could be distinguished readily from the latter by the marked differences that exist in the shape of their heads and bodies. This fellow was less common at Ithaca than N. irrorata. It re- mains much submerged and this may account for the infrequency with which it was captured. On April 29, two mating pairs were taken in the west pool of Ringwood Hollow. They were brought to the laboratory, and when placed in a battery jar, mated again. They remained in copula as long as the observation was continued — a half hour or more. Since Hagemann, according to Wefelsheild, reports Corixa remaining in copula 1 to 2 days, and from our experience with other water bugs, we would not be surprised at a long duration for the process in this bug. During the day, April 30, 14 eggs were laid — large, white eggs, at- tached to the stems. These eggs are considerably larger than those of N. irrorata. Thirty eggs were present May 4. One of the males died May 6 and was pinned up. On May 10 there were 26 more eggs. Thus in the first twenty-four hours the two females averaged 7 eggs apiece, this average falling off somewhat later. On May 9 a few of the eggs were showing pink eye spots. Some of these were photographed and are shown on plate VIII. May 19 many of the eggs showed very dark red eye spots and gave evidences of hatching shortly. The first hatched on May 23. A careful study of these newly hatched was disappointing in a way. In- stead of coming to surface, they remained submerged. The newly hatched are white with transparent abdomen and limbs. The guard hairs of the abdomen hang limp. Two little fellows hatched at 1:10 p. m. They were active ten minutes later, making series of backward somersaults, then resting as though exhausted. All efforts appear to be to attain the sur- face film, but at 2:20 they were still unsuccessful, and when resting on the bottom of the jar were indifferent as to which side was up, back or venter. Five o'clock came and still they were below, the guard hairs hanging limp upon the venter. Finally the next day some fresh water was added and some bubbles left upon the surface. Into these I coaxed one nymph, with the result that it filled its guard hairs instantly and darted below! This fellow was transformed of a sudden into a very ac- hungerford: aquatic hemiptera. 183 tive creature. The other nymphs were still slow and inactive. On May 24, at five p. m., two were still alive, though their guard hairs were non- functional. This tardy coming to the surface seems to be a feature in the behavior of the newly hatched of this bug. The habits of the adult and the needs of the larvas appear to be different from the others studied. The last adult of the overwintering generation was taken early in July. The species was too rare to accord satisfactory study in nature. Here follows a description of the egg and young nymph: The Egg. Size. Length, 2.21 mm.; height, viewed laterally, .78 mm.; width viewed from above, .754 mm. Color White, with surface quite strongly reticulate so that surface is rough. The chorion is quite tough. Shape. Elongate oval, micropylar end somewhat truncate; caudal end more pointed. - As with other Notonectid eggs the micropyle is a curved truncate cylindrical peg. The egg is attached to the plant stem or other support by a trans- parent pad of mucilaginous material. This egg is proportionately quite large. See the drawings on plate XIX. They are drawn to the same scale and show how much larger this egg is than that of Noto^iecta ir- rorata, a bug of nearly the same size. First Instar. Size. Length, 2.73 mm.; width of both, 1.248 mm.; width of head, 1.092 mm.; width of front of head between the eyes, .546 mm.; distance between the eyes, .442 mm. Color. Body white and abdomen and limbs of newly hatched trans- parent, the hairs smoky, eyes red and prominent, antennae and beak dark. The limbs are also sometimes dark in the older nymphs. Structural Characters. The antennae are directed downward, 3-seg- mented, basal segment very short. The tarsi are 1-segmented and end in two claws each. The claws of the hind tarsi are not conspicuous. The middle femora have, on their posterior margin, at least 2 spine-bearing tubercles. The posterior femora have 10 or 11 stout spines (on posterior margin) plus 2 longer ones at distal end. Notonecta irrorata. Habitat. This is a handsome bug of velvety brick red and black, and one of the largest species of back-swimmers. Bueno tells us that it likes the shadows of the bank, of overhanging limb, or of aquatic vegetation. Surely its mottled pattern of dark colors would serve it well in such haunts. We have found it very abundant at the field station and in the Meadow pool at Ringwood Hollow, Ithaca, N. Y. Hibernation. It spends the winter months in the deeper ponds and spring-fed open pools, flying from these quarters to shallower waters for breeding. At Ringwood Hollow this bug was present in considerable numbers in the rather deep leaf-strewn pool just west of Winterberry 184 THE UNIVERSITY SCIENCE BULLETIN. pond in late autumn and early spring. The migration from this pool occurred in a very few days of warm spring weather. A few days after taking mating pairs in numbers on April 29, the pool was almost de- serted, scarcely one was to be found. An examination of the Meadow pool, a quarter of a mile away, found them very abundant. Subsequent surveys indicated that the latter pool was the breeding place of this bug, for nymphs of this species swarmed the pool, forming, in fact, the domi- nant type of insect life. Very few nymphs were ever taken in the winter-quarters pool. The migration to deeper ponds and pools is doubtless due to a desire to secure unfrozen waters. They have been observed swimming slowly beneath the ice at the Field Station, Ithaca, N. Y., in early February. Mating. The mating begins in early spring, and occurs in the water, the male usually occupying a position to the left side of the female. The pairs have been observed to remain in copula for two and three hours, swimming about in the water, and the female even catching prey. Mat- ing pairs may be taken over a considerable time, but about the last of April they appear to be most active. Oviposition. In the matter of oviposition this species is the most in- teresting of all the members of the genus in this country, for, as else- where stated, it inserts its eggs in the tissues of plants. On plates VIII and XXII are shown the photographs and the figures of the eggs in- serted in moneywort and in water-soaked typha blades. One figure shows two eggs inserted in a bit of water-soaked leaf of typha through one aperture. As a rule, however, they are imbedded singly, wholly or in part, depending upon the nature of the material serving for support. The cephalic end of the egg is directed toward the opening. Females deprived of vegetation of sufficient diameter to permit the insertion of eggs (such as Chara) will hide them in mud and debris lodged in the axils of the plant. In only two cases were they loosely affixed to the chara. Incubation. The first eggs discovered wei*e on May 12. They may have been laid before this date, for they began hatching May 18. In another aquarium some eggs were laid May 12, red eye spots were show- ing June 2, and hatched by June 8. Another lot, laid between May 25 and May 27, showed red eye spots June 11, and began hatching a few days thereafter. Thus the egg stage of this species is comparatively long — some two or three weeks, or even longer. Hatohdng. The time of hatching in the laboratory began May 18. The first nymphs were taken in nature during the first week in June. The hatching process has been outlined in connection with A'^. iindulata, but some special features that were observed in connection with this species are worth noting. In attempting to study the behavior of newly hatched nymphs, the eggs were kept under constant observation for many hours. One of the striking facts of interest is the activity of the nymph within the egg some hours before hatching. One evening when a number of eggs were expected to hatch they were hungerford: aquatic hemiptera. 185 watched closely for hours. One attracted attention especially because the embryo was seen to be moving within its shell. One observation found it in the position shown in the drawing on plate XXII, fig. 3. A little later the embryo had rotated upon its longitudinal axis so that the eye spot on the right side in the drawing was on top. Fifteen minutes later the right eye had continued its rotation until it held the position on the left side. In ten minutes more it was in its original position again. This movement of the embryo, as followed by the pink eye spots, continued at intervals for several hours. Emergence was expected at any moment, but did not take place for many hours after the writer had despaired of seeing the event take place. Number of histars. There are five instars, which after the first are much alike, and to be distinguished by the dark markings on the sides of the abdomen. Maturity. The overwintering adults mate and begin egg laying in May. The first nymphs in nature were noted in the first week in June. By the last of June they were in all stages up to the fourth. On July 1, they were coming into the fifth instar at the Meadow pool, where the nymphs were most abundant. Frequent visits were made to this pool at Ringwood to observe the first adults of the new generation. While there were overwintering adults alive in the laboratory, careful collect- ing showed they had disappeared from this pool, so great interest was aroused in the behavior of this species in this Meadow pool. On July 7 there were many fifth instar forms, but no adults. I brought some of these to the laboratory and placed them in an aquarium, where the first adult came forth July 18. The next day a trip was made to Ringwood, and the Meadow pool contained many newly emerged N. irrorata adults ! Beautiful fellows they were, too, with their velvety, richly-colored backs! There is no mistaking these fellows for the older generation. Now, the next step was to determine if these fellows would bring forth another generation. Adults were brought to the laboratory and confined in an aquarium. The writer left them in the care of a friend, who reported that no eggs were deposited, and some were alive on October 22, when the experiment was abandoned. Only three or four individuals were followed, and the sex of these not fully established, so little data can be given concerning any evidence of a second generation of this species in New York state. LABORATORY RE-\RING. One series will indicate the various stages and the duration of time required for each. On April 20, three N. irrorata taken at Six Mile pool were placed in a glass battery jar with some fresh sprigs of Money- wort taken from above the water line. On May 12 eggs were discovered imbedded in the stems of the plant. These began to hatch on May 18. Some of these changed to second instar June 1, to the third June 9, and to the fourth June 20, to the fifth July 1, and to the adult the middle of July. These nymphs had been isolated in small stenders and jelly glasses and fed Cyclops and Ostracods. The first-instar fellows were seen to eat Ostracods nearly as large as themselves. When first hatched the 186 THE UNIVERSITY SCIENCE BULLETIN. njrmphs are clear white, with red eyes as seen from above. The limbs are transparent as is the abdomen also. The antennae, claws and hairs are dark. In ten minutes the limbs begin to get smoky. When they have hatched within the water the guard hairs of the abdomen hang limp. The insect seems water-logged. It comes up to the surface head up, and repeatedly sinks back to the bottom exhausted. Finally a stronger effort than before enables it to hook the front claws into the film, then after a sudden turn it goes down with an air bubble imprisoned beneath the abdominal guard hairs. In a battery jar the adults were active for a long time. The adults liked to cling beneath the rubbish and Moneywort tangle. They were fed the nymphs of damsel flies and Corixids. On June 25 the eggs were present in all stages from those showing red eye spots to those newly laid. The last of the three backswimmers was alive and active July 9 and the notes fail to show her fate. This account shows that the egg laying can be carried out under laboratory conditions and that it lasts from early May to the end of June at least. Fecundity. On March 26 a female was dissected and found to con- tain 252 ova, several of which were nearly ready for laying. The period of oviposition lasts from early spring until into June, in the laboratory not more than a half-dozen eggs being laid on any one date. Longevity. Adults certainly are capable of living at least a year. There is evidence to indicate that adults of the previous year may oc- casionally live over until the new generation comes on in July. They are few, however. If cared for in the laboratory they might exist well through the second season. Food Habits. Like others of their kind, they are predators. In their first stages in the laboratory they were given Ostracods and other small Entomostraca, also Corixid nymphs. By the time they reach the third instar they can master adult corixids of Palmocorixa genus (when they can catch them.) As elsewhere noted, the adults show discrimination. They caught but immediately liberated some pink Phyllopods offered them. Behavior. The late instars are given to spending considerable time at the surface, like the N. undidata. The adults, however, are not so in evidence and come out in the sweepings of the net as pleasant surprises to add zest to the activity of the amateur collector. Description of Stages. Egg. Size. Newly-laid egg, length, 1.51 mm.; diameter, .572 mm. Shape. Elongate oval, but shorter in proportion to its length than N. variabilis, N. undidata or N. insulata. In lateral view the anterior end of the egg is seen to slope back from the base of the micropyle more than the others. (See pi. XIX, fig. 6.) It is this portion of the egg that is exposed as it lies in the plant stem. * Frisch, 1728, said that the young stages of N. glauca were more often seen than the adults. HUNGERFORD: AQUATIC HEMIPTERA. 187 Color. White when first deposited, then amber as the red eye spots begin to develop. The ventral surface of the embryo (upper surface of egg) begins to shovi^ sooty black. The micropylar plate darkens. The micropylar tube remains w^hite. Later the darkening embryo within lends a color pattern, to the outside. Structural peculiarities. Shell rough, tough, irregularly, hexagonally reticulate. The egg increases in size as embryo develops within. First Instar. Size. Length, 2 to 2.6 mm.; width of body, .99 mm.; width of head, .91 mm. ; width between the eyes at front of head, .494 mm. ; distance between the eyes, .364 mm. Color. Much darker than any other backswimmer nymphs examined. In ventral view, the legs, beak, hairs and venter, sooty black. Eyes dark red. Hind tarsi mai'ked transversely by a broad band of lighter color and the margins of first three or four abdominal segments lighter also. Frons lighter than beak. In dorsal view, the head is light between the eyes. Thorax and abdomen dark save where the light band of the head extends backward on the thorax to the abdomen. Margin of basal seg- ments of abdomen somewhat lighter. (See drawing, pi. XIX, fig. 2.) Structural peculiarities. Besides its much darker color, which readily separates it from the other nymphs, the posterior margin of the middle femur is equipped with only one well-defined, spiniferous tubercle. The first instar nymphs of the four species reared may be distinguished as follows:* A. Color dark, smoky testaceous. Posterior margin of middle femur with one long spine on a tubercle. N. irrorata. AA. Color light. Posterior margin of middle femur with 2 spines on tubercles. B. Length, 2.6 mm. or more. Posterior margin of hind femur with 10 to 11 stout spines, plus 2 longer ones at distal end. N. itisulata. BB. Length, less than 2.6 mm. Posterior margin of hind femur with 7 or 8 short spines, plus 2 longer ones at distal end. C. Legs conspicuously banded. Spines on posterior margin of hind femur not conspicuous. Margin of abdomen nar- row, rather slender body. N. variabilis. CC. Legs not conspicuously banded. Spines on posterior mar- gin of hind femur conspicuous. Margin of abdomen wide, robust nymphs. N. undulata. Second Instar. Size. Length, 3.27 mm.; width of body, 1.5 mm.; width of head, 1.2 mm. Color. For color pattern see later instars. Structural peculiarities The median abdominal carina is now present on the venter and margined with hairs. Posterior margin of mesothorax more arcuate than in first instar. The distance between the eyes at ver- * First instar Notonecta nj'mphs have no ventral abdominal median carina. 188 THE UNIVERSITY SCIENCE BULLETIN. tex plainly less than the width of one of the eyes. The femora of the middle legs now have two strong spines on the posterior margin. The basal one is borne upon a strong tubercle. Third Instar. Size. Length, 3.51 mm.; width of body, 2.21 mm.; width of head, 1.56 mm. Color. For color pattern see later instars. Structural peculiarities. Ventral view: The limbs are all equipped with spines. Some of these on the front and middle legs are arranged to effect a loose guard of hairs when the limbs are flexed. The front and middle limbs are also flat or concave on their posterior side and guarded on either margin by several spines. The front tibia has an irregular row of about six in the ventral edge of its posterior margin, and a definite row of the same number on the dorsal edge of this posterior margin. The tarsus is shorter than the tibia and has two spines on either margin and ends in two well-developed, subequal claws. The middle femur is thickened and on its posterior border are three long spines, the basal one on a strong tubercle and a short peg-like one. The middle tibia has 3 spines on its anterior margin, six short ones on the ventral margin of the postei'ior side, and three long ones on dorsal margin of this same side. The dorsal caudal margin of tarsus is provided with four spines and the tarsus is terminated, by two unequal claws, the upper one of which is nearly a half larger than the lower. The hind limbs are strong and furnished with many short spines. The posterior margin of hind femur has a row of these shoi't spines, eight or nine large ones quite evenly distanced one from another, and three spines are present at distal end of the ventral side of femur. Several rows of short spines on tibia and tarsus and swimming fringe on both of these segments. Dorsal Vieiv. Posterior margin of mesothorax more deeply arcuate, the wing-pads extending back more than one-third of the length of the margin of the mesothorax and metathorax together. Margins of abdomen barred with dark markings, base of second abdominal segment very dark also. Fourth Instar. Size. Length, 7 mm.; width of body, 3.12 mm.; width of head, 2.08 mm.; distance between eyes at vertex, .91 mm.; distance between eyes at closest point, .52 mm. Color. As in fifth instar, save the dark band on mesothorax. Wing- pad is single and bi-oad. Structural Peculiarities. Ventral view: General arrangement of spines on the legs about as in third instar ; front tibia as in third instar ; front tarsus shows the two spines on the dorsal edge of the posterior margin, the other spines obscure. Middle femur now shows a definite tuft of about four strong spines arising from the tubercle, two other strong spines (sometimes a weaker one also) and a black-tipped spur or tooth not far from distal end of femur. The middle tibia has six spines either side of the posterior surface and three or four on the rounded hungerford: aquatic hemiptera. 189 anterior surface. The middle tarsus has an irregular row on lower posterior margin and a definite row of four spines on the upper. Tarsal claws unequal as before. Hind legs as in the other instar in general equipment, posterior margin of hind femur with a row of about 30 short spines of nearly equal length, the distal pair being a little stronger than the others, and close together. Three spines mark the distal ventral margin of the femur. The hind tibia possess tibial combs each in two groups, one consisting of four stout spines, and the other of three. Dorsal View. The wing-pads of mesothorax extend back more than one-half the length of the margin of mesothorax and metathorax taken together. Fifth Instar. Size. Length, 10.6 mm.; width of body, 5.1 mm.; width of head, 2.86 mm.; distance between eyes at vertex, .936 mm.; distance between eyes at narrowest point, .52 mm. Color. In dorsal view, eyes dark red, thorax white with greenish tinge; prothorax with a smoky band near each lateral margin and parallel with it. Postero-lateral angle smoky. Mesothoracic wing-pad with two longi- tudinal smoky bands joined posteriorly by the dark band of the apical margin. Posterior margin of metathorax marked by a smoky line that diffuses into a band at lateral margins. The abdomen is chalky white, strongly marked bjT- transverse bands and spots of smoky black. Basal portion of abdomen is crossed by three rather wide bands. The following two bands are broken on the dorsum, but the two caudal transverse bands are broad and heavy. In ventral view, a median dark band divides the head longitudinally. The base of the beak and beak dark; limbs testaceous, equipped with black hairs, and femora with longitudinal stripes of darker color; con- nexivum with six pairs of dark rectangular spots; guard hairs dark. Struct2'.ral Peculiarities. Ventral view, median abdominal carina long, in three sections and extending nearly the length of abdomen; front femur with 4 strong spines on upper margin of posterior side; tibia, 6 spines on either edge; tarsus as in 4th instar. Middle femur now has, besides this clump of spines on the tubercle, four other spines and the spur, which is now longer than in previous instar. Posterior margin of hind femur with about 44 short spines plus three longer ones at distal end. Distal ventral margin of femur with five strong spines. Tibia with distal ventral margin equipped with two sets of four or five strong spines. Dorsal view: Wing-pads extend back to abdomen in this instar. Summary. This bug has been reported from New York. It prefers clear waters where it frequents the shelter of shaded places. The eggs are placed in the tissues of aquatic plants instead of upon the plant as is the case with the other members of the genus. Egg laying begins in May and the adults of the first generation come to the adult stage in mid July in New York. There is insufficient evidence to state whether a second generation appears. 190 THE UNIVERSITY SCIENCE BULLETIN. Biology of Notonecta undulata Say. Habitat. Notonecta undulata, besides being the most widely-dis- tributed form, seems to be able to adapt itself to a wider range of cir- cumstances than most of the others. The writer has taken it in clear spring-fed pools in New York and in the stagnant scum-covered waters of muddy ponds in Kansas. Uhler, 1876, says "it inhabits the foulest pools, in dirty slush and slimy ponds it revels in full enjoyment of the filth." Barber, 1913, in a popular paper on aquatic Hemiptera, makes a similar reference to its habitat. Thus it may be noted to be less sensitive than many others of its genus to its environment. When the small bodies of water recede during the prolonged period of dry weather, which we sometimes have in late summer in Kansas, it is among the last to take wing to more favorable situations, a fact which is not to be accounted for on the basis of weak powers of flight, for it does on occasion fly very well, as appears to have been noted for the European forms at an early date. Aldrovandus spoke of them as amphibious bees and Swammerdam, at the close of his discussion of the Notonecta, a name applied to them by Mouffet, 1634, makes the following interesting remark in regard to the migration of water bugs : "As all the insects hitherto enumerated have wings, some of them flying in the daytime and others at night, it is easy to conceive that they may be very speedily generated in all standing waters." In the first warm days of spring, the writer has observed them com- ing by the dozens and alighting in a small road-side pool. Thus their range, which was restricted by the drouth of the previous fall, was again extended to the many favorable pools of spring and early summer. There are several records of Corixid migrations in this country but only one, so far as the writer knows, for Notonecta. In September, 1846, near the head waters of the Mississippi, S. G. Simpson reported a swarm of "N. glauca" which extended over 25 or 35 miles. This species, if a Noto- nectid at all, was doubtless the common N. undulata. Hibernation. The adults may be taken any time during the winter when the waters are open enough to permit collecting. They pass the coldest portion of the year in the mud or among the rubbish and dead leaves in the pool. They can even spend as long as six weeks in damp piles of dead sticks, so it does not necessarily follow that they perish be- cause pools diminish during weather when they are but sluggishly active. Mating. Mating takes place with the first warm days of spring, and as with other water insects takes place beneath the surface and lasts for some time. Oviposition. The eggs are glued to supporting vegetation, sticks, posts, rocks, tin cans, or even to snail shells that lie submerged. A very satisfactory idea of the eggs may be obtained by viewing the photograph on plate XXI. Incubation. The egg stage varies from five days to two weeks, de- pending upon the temperature. hungerford: aquatic hemiptera. 191 Hatching and Behavior of Newly Hatched. Hatching takes place upon bursting the cephalic end of the egg as shown in the photograph. The nymph comes forth swathed in a clear membrane, gradually working its way, by backward and forward movements, till it is nearly clear of the egg shell, whereupon the embryonic sheath splits and slowly the new bug frees itself, the swimming legs being the last to leave the shell. As the legs are freed they spring out into position. When at last the little bug is clear, it rests as though exhausted, then it makes, during the next fifteen or twenty minutes, intermittent endeavors to attain the surface. In these efforts it approaches the surface head uppermost and is heavier than the water — dropping to the bottom as soon as its struggles cease. Finally it may succeed in hooking a front claw into the surface film where it will hang suspended for some minutes. Finally it turns on its side, pierces the surface film, then darts below, the guard hairs closed over a bubble of air. Up to this time the guard hairs of the abdomen have rested limp against the body. Number of Instars. There are five nymphal instars. Food Habits. The food habits of the first three instars are very in- teresting to watch. The Uttle nymphs make a specialty of Ostracods and other little Entomostracans. They will devour each other and thus each little nymph must be isolated if he is to grow up. Behavior. This species, more than any other, rests at the surface film. Christine Essenberg has written much concerning four species of Backswimmers. DESCRIPTION OF STAGES. The Egg. Size. Length, 1.625 mm. to 1.813 mm.; diameter, .5 mm. to .6 mm. Shape. Elongate oval; becomes plumper as embryo develops within. Color. White when first deposited. The embryo lies with its back to the attached side of the egg as a rule. After a few days incubation the eye spots begin to appear as faint pink blotches, darkening as de- velopment takes place, till shortly before hatching the black hairs bor- dering the various portions of the body of the nymph are visible through the chorion. The surface of the egg is tough and rough, due to the fact that it is sculptured in irregular hexagons. The micropyle is a curved tube arising from a circular differentiated area as shown in the drawings on plate XX. First Instar. Size. See table below. Color. General body white, eyes red, hairs and spines black, antenna smoky black. When first hatched the abdomen especially transparent and the movements of the organs plainly visible within. Tarsal claws all conspicuously black. Structural Peculiarities. The most characteristic feature of the first instar is the absence of the tuft of hairs which in all succeeding in- stars is found on a median ventral carina of the abdomen. The eyes are relatively far apart. The antennae are apparently 2-segmented and di- 192 THE UNIVERSITY SCIENCE BULLETIN. reeled downward (really three segments). The tarsi are all 1-segmented and end in two claws. The tarsi of the hind legs are fringed with hairs. The middle femora are furnished on their caudo-ventral margins with two strong bristles set upon elevations. Second Instar. The presence of the tuft and fringe of hairs on the ventral abdominal carina is the chief addition over that of the previous stage. The rear margins of the middle femora are now equipped with three strong bristles and there is a suggestion of the tooth or spine that becomes prominent in the succeeding instar. Antennae 3-segmented. First segment short, disc-like, second somewhat globose and third elongate. Third Instar. The caudal margin of the mesothoracic femur now carries a well- developed tooth as well as the three stout spines noted in the second instar. Tibia and tarsus of hind leg now fringed with hairs — wing- pads as in figure 4, plate XX. Fourth Instar. The middle femora now bear very stout processes in the line of the caudal row of spines. A series of short processes on the ventral side of this segment take the place of minute rugosities of the previous instar. Fifth Instar. The tooth or strong spine on the mesothoracic tibia is now extremely wide at its base. The limbs are stouter than previously and the vdng- pads now have the position shown in figure 4 of plate XX. In the table below the measurements are in millimeters and based on reared material. The adults are certainly smaller than those taken in Ithaca, N. Y., though practically the same as specimens from nature in Kansas. These figures are intended to help in determining an instar. The series measured is not large enough for purposes of generalization. TABLE OF MEASUREMENTS. General Measurements. HiN'D Leg. Middle Leg. Fore Leg. Stage. 3 E.' as: a. Between Eyes Syntbl. to Vertex . . . i so' Tarsus B c: c 3 c 05 1st instar .... 2.125 1.062 .833 ,43 .818 .687 .707 .875 .437 .437 .313 .37 .3/5 .275 2d instar 3.1 1.41 1.06 .395 .73 .975 .975 1.12 .63 .625 .437 ,5 53 .37 3d instar 4,66 2. 14 .4 .66 1.47 1.47 1,53 1. 1. .65 ,75 .762 .57 4t5 instar. . . . 6.125 2.75 1.87 .53 .66 2.125 2. 0 1 38 1.37 .93 1. 1.12 .75 5th instar . 8.5 3.5 2.5 .66 .582 3.1 2,89 2.75 2 1 2. 1.16 1,5 1 58 1.12 6th (male).... 11 4 4. 2.86 .4 .4 4.1 3,48 2. 86 2.68 2.57 1.43 1,94 2.28 1.26 6th (feTiale^ . 11.4 4.28 2.97 .42 .41 4,28 3.54 2.07 2.85 2.68 1 66 2, 2.28 1.43 General Notes on Development. There are certain constants of struc- ture that are carried through all the nymphal instars. The mesothoracic HUNGERFORD: AQUATIC HEMIPTERA. 193 legs may serve as an illustration of this point. In all the instars the tarsi end in unequal claws as in the adult, and the tibiae possess a row of five bristles on their caudo-ventral margin and the tarsi three such bristles. The metathoracic tarsi end in an unequal pair of claws which are prominent in the first instar (plate XX, figure 10), and which become less and less conspicuous as development proceeds till in the adult stage their similarity to the other structures of the swimming leg has led to the common statement that the tarsal claws of hind legs are ab- sent in the adult. Upon transforming to the adult stage the 1-segmented condition of the tarsi is replaced by a 2-segmented tarsus and the 3- segmented antennae become 4-segmented. (See plate XX, figures 6 and 7.) The eyes occupy an increasingly large proportion of the head in successive instars, a point not properly indicated in the drawings which were made from living bugs in the water. Summary. Notonecta undiilata is the most widely distributed of all our backswimmers. It lives well in the aquarium and may be reared from deposition of the egg to the adult stage in some forty days if placed in isolated jars and given proper attention. The young stages thrive on a diet of Ostracods and the advanced nymphs do very well on immature and small Corixids for a food supply. In Kansas there are two main broods in a season, one reaching the adult stage in June, the other in August. Since these insects draw quite largely in their young stages upon the Ostracods and similar organisms, which represent a chief food supply for young fish, as well as preying upon a small fish directly, as has been noted several times, they deserve more careful study. This task is greatly facilitated by a workable key to the species and by some knowledge of their feeding habits. Biology of Notonecta. Variabilis. This species was very abundant in the pools about the Field Station, Ithaca, N. Y. The writer has never taken it in Kansas, although it should occur there. It likes fresh water, and clings to submerged tangles of water plants. The Egg. The egg is deposited upon a pad of gelatinous material. This egg appears to be more truncate at anterior end than the other eggs. Size. Length, 1.69 mm.; width, top view, .65 mm.; width, side view ( heigh th), .78 mm. Color. Surface is hexagonally reticulate; pearly white when first de- posited, then turns first amber and then smoky as embryo develops, especially at anterior end. Micropyle tube is long and directed toward attached side of egg. Shape. As in other species. First Instar. Size. Length, 2.08 mm.; width of body, .936 mm.; width of head, .78 mm. l.-i — Sci. Bui. — 1669. 194 THE UNIVERSITY SCIENCE BULLETIN. Color. Dorsal color greyish white, eyes red, margin of abdomen and limbs pale testaceous banded with dull smoky brown or black. Venter. Hairs dull black, beak and part of frons very dark smoky, as are the antennas, which are directed downward. Coxse, trochanters and femora dark, fore and middle tibiae dusky, hind tibia darkest in middle, distal end light. Tarsi all dusky, with broad transverse median band of testaceous. The color marking of hind leg is distinct. The outer one- third of tibia pale, rest of segment smoky testaceous. Tarsus very dark smoky, almost black, with a wide transverse pale band occupying more than one-third of the segment. This leaves both ends of segment dark. Structural Peculiarities. No ventral abdominal median carina present. Distinguished from other first instar nymphs by table given under A^. irrorata. Biology of Bnenoa margaritacea Bueno. So far as the writer knows, there has not been an account of the biology of any species of either this genus or Anisops, its near relative, aside from his own notes published in the Entomological Nervs in 1917. In this paper he presented some observations on Buenoa. margaritacea Bueno. This is a slender silvery backswimmer, more or less of pink showing upon the dorsum of the thorax. The venter of the abdomen is a deep red in living specimens. This darkens in museum material, and has led to the error of the description in calling it black. Uhler said that Anisoqjs platijcnemis preferred the cold spring water in Maryland where he had taken it late in October after the frosts had set in. Bueno notes that it prefers the more open waters, and the writer has found it in muddy ponds in Kansas where it floats submerged in open water. Oviposition. Attempts to secure eggs of this bug failed until exami- nation of the ovipositor made it apparent that the eggs were hidden in plant tissues. They were then found in floating plants in the pond, and secured in the aquarium by providing cattail leaves and smartweed stems. One uprooted smartweed plant, floating in the Smith pond, was almost riddled with oviposition incisions. Not only were the stems swollen and distorted by the many eggs they contained, but the leaves were employed as nidi with varying degrees of success. The leaves were punctured, and the egg, when present, rested suspended beneath, attached by the collar shown in the drawing on plate XXIV, to the upper surface margins of the incision. The many perforations or slits through the leaves gave their testimony to the many failures in attempting to employ so thin a struc- ture for nidification. The eggs are placed in the plant tissue with one bit of surface exposed. Number of Instars. There are five nymphal instars, and the duration of the various stages is much the same as in other back-swimmers. Adults are to be taken from early spring to late fall. About the middle of June they are most abundant in all stages of development. Food Habits. One striking point in their biology is the adaptation of their two slender anterior pairs of limbs to food getting. The food of these insects consists of the small entomostracan Crustacea, and the four anterior limbs are margined with rather long spines which form when HUNGERFORD: AQUATIC HEMIPTERA. 195 flexed a splendid crib for the retention of these little animals. Some- times a half dozen or more are detained thus at one time. We have at- tempted to illustrate this device on plate XXIV, showing the limbs open in one drawing and flexed in another. They sometimes attack other insects, such as Corixids, but rely almost exclusively upon the little organisms named. Behavior. These insects do not rest at the top as does Notonecta undulata, but may be seen swimming slowly, or even poising in mid- water some distance beneath the surface. They do in fact seem in better equilibrium in the water than the Notonectse. They come to the sur- face and expose the venter of the abdomen by the spreading of the guard hairs, as do the other back-swimmers when in poorly aerated waters. The males possess stridular areas upon the inner faces of the femora and tibise, and also on the sides of the face at the base of the beak. These are shown in the drawings on plate XXIV. The tibial structure is borne on the inner face of a spur near the base of the anterior tibia. When the fore limbs are brought up to the head, it will be seen that the stridular areas of the limbs meet those on the base of the beak. See the figure on plate XXIV. The production of sound is doubtless the purpose of these structures. European workers have recorded Notonec- tids as capable of producing chirping sounds. Miall quotes Redfem to the effect that Notonecta makes a noise like the word "chew" repeated three times. The Egg. Size 1.125 mm. long by .406 mm. in its widest diameter. The size increases somewhat with the development of the embryo within, which causes a bulging of the stem in which the egg is inserted. Shape. The egg is elongate oval when seen in surface view with the cephalic end the more pointed. (Surface view — the side, a portion of which is exposed to view as the egg lies embedded in the stem.) In lateral view it appears nearly straight in the outline of its upper sur- face, while the lower is quite strongly curved. Color. Pearly white when first laid — the surface hexagonally reticu- late as in the eggs of Notonecta. A smooth and shiny elongate oval area occupies the anterior half of the upper surface. This is the portion exposed and is margined by a whitish band which marks the union of the egg with the surface of the stem when "in situ." As the embryo develops, the entire egg becomes deep greyish yellow and the red eye spots and other red mai'kings show through the chorion. The part exposed becomes dark amber in color and very shiny in appearance. The surface appears reticulate under magnification. First his tar Nymph Size. Body length, 1.85 mm.; body width, .625 mm.; head width, .5 mm.; distance between eyes, .156 mm. Fore limb: femur, .25 mm.; tibia, .35 mm.; tarsus, .25 mm. Middle limb: .387 mm., .333 mm., and .275 mm., and hind limb, .625 mm., .630 mm., and .625 mm. for femur, tibia and tarsus respectively. 196 THE UNIVERSITY SCIENCE BULLETIN. Color. Ventral aspect: White — the abdominal fringe of hairs, the ventral abdominal tuft, the hair tufts before the hind coxae and those of middle coxae — black. The hairs fringing the hind tarsi are smoky black as are the middle and fore tibia. Eyes dark red. No indication of the red pigment in the abdomen so conspicuous in older nymphs and adults. White with the red eyes — the only conspicuous marking. Structural Details. The absence of the median abdominal carina from the venter, as is the case also v^^ith N. undulata nymphs, is the first and most striking peculiarity. The interspace betw^een the eyes is large. Beak four-jointed as in adult. Tarsi all one-jointed, terminat- ing in two claws. The spiny armature of fore legs is more generalized than in later forms. The fringe of the hind legs confined to the margins of the tarsi. The Older Nymphs. In order that space may be conserved, a table of measurements for the various instars is presented below and a discussion of the changes in structure as development proceeds appended. MEASUREMENTS IN MILLIMETERS OF NYMPHS OF B. MAROARITACEA. Body Measurements. Leg Measurements. Instar. Length. Width. Width head. Fore Leg. MiDDi-E Leg. Hind Le;:. Femur. Tibia. Tarsi. Femur. Tibia. Tarsi. Femur. Tibia. Tarsi. 1st 2nd 3rd 4th 5th 6d^.... 6?.... 1.85 2.25 3.225 4.5 5.75 7.* 7.5 .625 .702 .938 1.625 C.3 2.2 2.2 .5 .625 .832 1.063 1.365 1.62 1.75 .25 3.75 .5 .625 .8 1 1. .35 .438 .62 .75 1.2 1.35 15 .25 .313 .487 .563 .81 1. 1. ..387 .5 .75 1.063 1.5 1.75 2. .333 .438 .625 .875 .625 1.37 1.5 ,275 3.75 .6 .725 1.125 1.25 1.3 .625 .75 1.1 1.625 2.25 2.5 3. .63 .76 1.1 1.375 1.85 2.25 2.62 .625 .81 .975 1.28 1.6 1.95 2.3 * Bueno gives length of species 6.7 to 8.1 mm.; lat., 2.23 mm. The adults of this species are separated in the synoptic table from the other two species on the basis of the body length, which is greater than 6 mm. This, with a diagnosis of the instars from structural characters, may serve to separate the nymphs of this species from those of the others. The table of measurements above is based on an average of ten specimens of each instar. A larger number would be desirable to obtain figures dealing with ratio of growth. The writer believes that an examination of a sufficiently large amount of material would show for head-widths and limb measurements a ratio of 1 : 1.25. That is to say, the width of the head of the second instar nymph would be ap- proximately 1.25 times that of the first Instar nymph. Upon attaining the adult stage a sexual dimorphism becomes appar- ent. Besides the structural differences of the genitalia, the anterior legs hungerford: aquatic hemiptera. 197 of the male possess on the inner faces of the femora and tibiae peculiar stridular areas. The tibial structure is borne on the inner face of a prominence, which is formed by the elevation of the inner angle or margin of the tibia nar its base into a thin but elongate spur. This spur is lacking in the female, and not discovered in the nymphs. (See pi. XXIV, figs. 5 and 6.) The Development Changes. Head. The notocephalic margins of the eyes, which are near together and nearly parallel in the adult, are relatively much farther apart in the first instar nymph. In the newly hatched bug, the distance at syn- thlipsis is nearly \z vddth of the head, with the margins of the eyes diverging broadly to the vertex. As the development proceeds from in- star to instar the eyes are brought nearer and nearer to their relations in the adult where the synthlipsis is reduced to about 7.14 per cent of the width of the head. The beak is 4-segmented and the antennse of the nymphs have much the form of those in the adults. Legs. The general form as in the adult. The tarsi of all legs 1-seg- mented and terminated by two claws. (The tarsi of the adults are 2-segmented and end in two claws.) Wings. The wing-pads are very conspicuous even in the later nymphal instars. By the third instar the pads appear on the antero-ventral mar- gins of the mesothorax as little flaps, the distal ends of which reach a position on a line with the trochanter of the fore leg when flexed. In the fourth instar they are much larger, the apices attaining to a position on a line with the distal end of the mesothoracic tibiae when the limb is flexed. In the fifth instar they are still closely applied to the side of the thorax, but the tips of the more opaque pads reach a point on a line with the distal ends of the hind coxae. Habits of the Species. Buenoa ynargaritacea is the common repre- sentative of its genus in the ponds and pools of eastern Kansas. It ap- pears to prefer the open water and is in much better equilibrium in its watery world than the Notovectie. Individuals of this species may be seen in large numbers swimming slowly or even poising in mid-water some distance beneath the surface. They abound in waters teeming with Entomostraca, upon which they largely feed, the crib formed by the closure of the anterior two spiny pairs of legs being nicely adapted to the retention of such prey. Their dexterity in the manipulation of this device and its efficiency in retaining small beings may be demonstrated quite readily under the binocular, and affords another of nature's illustrations of the fitness of form to function. Like others of the predatory class of water bugs, they do, on occasion, fall upon Corixids and other forms than the Entomostraca, but not with the regularity of many of the others. Adults appear from early spring to late fall. The eggs may be found in May, the nymphs begin to emerge by the middle of the month, and 198 THE UNIVERSITY SCIENCE BULLETIN. by the 15th of June form a dominant species to be noted in all stages of development, from egg to adult, in waters suitable to their needs. They are wilder and more difficult creatures to rear than the Noto- nectm, but no less interesting objects of study. So far as the writer is aware, there has been nothing noted hitherto concerning their biology, and he is glad to record for them something of the economy of their lives. Summary. This species is the common representative of its genus in Kansas ponds, whei-e it swims well out from the shore and some dis- tance beneath the surface. It feeds on the small crustacean life of the pool which it gathers in a spiny crib formed by the closing of the four anterior limbs. Its eggs are placed in the tissues of submerged plants fixed or floating in open water. Family NAUCORID^ Fall 1814. Fallen, Spec. Nov. Disp. Meth., pp. 3, 15. A. Taxonomy of NaucoridjE. Family characteristics. Broad, smooth bugs of moderate size, and greatly enlarged fore femora. The outer margin of the eye is continuous with the margin of the head, not protuberant, and caudal appendages are lacking. The antennae are shorter than the head and lie concealed. Ocelli are absent. The beak is 3-segmented. Membrane of the hemely- tra is without veins. The fore tarsi are 1-segmented; the middle and hind tarsi 2-segmented. The hind legs are not flattened for swimming. Aquatic, but little modified for such a life. KEY TO GENERA. A. Front margin of prothorax deeply excavated for the reception of the head. Amhrysus. AA. Front margin of prothorax not deeply excavated for the reception of the head. Pelocoris. Genus AMBRYSUS Stal. 1862. These Naucorids have the head set deeply into the prothorax. The body Is oval or sub-oval, and the head transverse, and truncate behind the eyes. Beak very short, lateral margins of pronotum entire, posterior angles, slightly retrorsely produced ; gular and prosternal carinas of equal height, continuous, middle of mesosternum longitudinally very obtusely elevated and subsulcate. Anterior femora very broad. Anterior tarsi single segmented. Claws lacking, tibias closely oppressed. The following adapted from Montandon: KEY TO AMBRYSUS. A. Pronotum smooth, shining, without punctation on the disc, some- times some rare indentations, set at regular intervals on the side. B. Head very wide — as wide, including the eyes, as half the width of the rear of the pronotum. C. With blackish spots or clouds. A. pulcheUus. CO. Without blackish spots or clouds. Head and pronotum entirely yellow, immaculate. A. jndchellus var. palHdulus. hungerford: aquatic hemiptera. 199 Key to Ambrysus — continued. BB. Head very sensibly narrower, including the eyes, less than half the width of the pronotum behind. Pronotum with a slight depression, sometimes very superficial, wrinkled trans- versely on the middle of the anterior border. C. Coloration darker, segments of connexivum darkened with posterior angle a little prominent. A. pudicus. CC. Coloration lighter, segments of connexivum not as above. A. drcumcinctus. AA. Pronotum densely punctate, especially laterally. B. Size small, below 8 mm. Median depression of the anterior margin of the pronotum feeble, transversely wrinkled. Color "claire." Width of the head, including eyes, a little less than half the width of the pronotum behind. Eyes con- verging in front. Length, 7.2 mm.; width, 4.5 mm. A. calif ornicus. BB. Size larger, above 9 mm. in length. C. Anterior margin of pronotum very visibly "reborde" (with a visible ledge) behind the eyes; depression of the middle of the anterior margin transversely wrinkled and punctate between the wrinkles ; interocular portion of the head narrowed in front; head with a very feeble longi- tudinal depression forming a median furi^ow, plainer behind. Length, 11.8 mm; width, 6.7 mm. A. ynelanoptenis. CC. Anterior margin of pronotum not or slightly visibly ledged (bordered) and then only in the middle. D. Anterior angles of pronotum very prominent, sharp. E. Average size larger (9.3 to 10.6 mm.) ; lateral sides of pronotum more dilated and more strongly arcuate without, dilation of embol- ium more pronounced. Coloration pale. A. 'mormon. EE. Average size smaller (8.6 to 10 mm.) ; lat- eral sides of pronotum less dilated and less strongly arcuate without; dilation of embol- ium less pronounced. Coloration deeper. A. heidemanni DD. Anterior angles of pronotum less prominent, almost right angles, scarcely pointed. E. Head narrow, as long as the width of the in- terocular space behind; length of the head and pronotum together a little greater than half the greatest width of the pronotum. A. punctieollis. EE. Head wide, length of the head and pronotum together equal to or a little less than half the greatest width of the pronotum. Pronotum 200 THE UNIVERSITY SCIENCE BULLETIN. Key to Ambrysus — concluded. equal to or imperceptibly longer than the head on its median line. F. Eyes very convergent toward front on almost their entire length, width of in- terocular space in the middle subequal to the length of the head, much narrower toward the front. Color de. r). Length, 13.3 mm. ; width 8.3 mm. A guttatipennis. FF. Inner edges of eyes subparallel or very feebly convergent toward the back, scarcely converging toward the front, only on the anterior third. Interocular space, even in front, wid'^r or subequal to the median length of the head. Color, clear yellowish, flecked with brown. Length, 13.7 mm.; width, 8.8 mm. A. signoreti. Genus AMBRYSUS Stal. Ambrysus pulchellus. Montd. 1897. Mont. Verb. Zool. Bot. Ges. Wien., XXVII, pp. 11, 16. "At first sight a little similar to A pudicus Stal. as to size and color, but proportionately a little less narrow; less narrowed behind; the small brownish spots a little more marked on the head and the pronot'im, which is not punctate on the margins, and without deoressions or wrinkles on the middle of the anterior border of the pronotum. The pronotum very little enlarged behind, the lateral margins almost parallel no'-te- riorly. With almost no transverse furrow; vei-y feebly marked on the margins. The posterior part behind the furrow pale, quite smooth, but covered by a few inconspicuous, very tiny black points. The head very notably punctate on each side near the eyes, these much larger pronor- tionately than in A. pudicus Stal, as wide with the eyes as half the width of the pronotum. Scutellum and elytra of a uniformly deep brown without spots or clear areas except the embolium, which is yellowish on the basal % for its entire width, the apical M bro^vnish. Margin of elytra is very slightly sinuate behind the em>"olium. Commissure of the clavus a little less than half the length of the scutellum. Connexivum yellowish with a slight amber band covering the tips and the bases of the segments. Posterior angles of the segments not prominent. Length, 8 mm.; width, 4.8 mm. Texas." Ambrysus pidchelhis Montd. 1897. Var. jiiiUididun Nov. var. "Length, 8 to 9 mm. Differs from the type by the complete absence of blackish spots or clouds. The head and pronotum entirelv yellow, pale, immaculate, smooth, shining, save some very superficial impressed • points, rare and little vis^iMe, near th^ anteriov fno;le of the pronotum and behind the eyes. The scutellum entirely yellowish, sometimes scarcely a little less clear than the pronctum. Corium of a dirty yellow or slightly brownish, quite strongly narrowing behind the embolium, although with- out apparent sinnositv, and leaving largel - uncovered the last segments of the connexivum, yellow, without spots or imperceptibly darker at their base. Posterior angles of the segments not protuberant. hungerford: aquatic hemiptera. 201 "Texas, Belfrage U. S. N. M., Washington and my collection. "This species in its form typical, of deeper color, is without any doubt very close to A. iiitidulus Montand, 1909, of Mexico. However, the corium appear always sensibly lefs developed, and the punctation of the anterior angles of the pronotum less accentuated." Ambrysus circwmcinctus Montd. Montaiuldii, Bui. Soc. Sci. Bucarest, XIX, No. 3, p. 5, 1910. "Form oval, hardly more attenuated in front than in the rear. Colora- tion dull uniformly yellowish on head and pronotum, a little infus- cated on the scntellum and the elytia. Length, 8 mm.; head medium rather weak, with the eyes quite convergent in front for almost their entire length, the convergence a little less accentuated behind. Anterior border of the head quite regularly arcuated and very narrowly blackish at the tip. which margin i= notably anterior to the level of the e^ es. The head above, at least, as long as broad, between the eyes behind, about three times wider between the internal posterior angles of the eyes than the width of the eye at the same level; posterior portion of the head sunken into the median incisui-e of the pronotum, visibly longer than the anterior portion behind the eyes; punctuation of the head very fine, rather dense, but irregular and inconspicuous. Hardly a little more accentuated near the eyes and in front. Vertex uniformly pale without apparent markings. "Pronctum with lateral margins feebb' but rather regularly arcuated and divergent behind for almost their entire length, save in region of the posterior angles where they are narrowly subparallel. The angles are almost right, or a little obtuse, and sightly rounded at the summit. The lateral margins are very narrowly blackish on their extreme lateral margin. Anterior angles of pronctum rather acute but not arcuate at the summit. Anterior margin of pronotum profoundly incised. The transverse median incisure is rather large, but quite profound, the lateral incisures well accentuated behind the e es. They are, however, a little less transverse than in A. puIchcUus. The entire surface of pro- notum rather uniformly yellowish, hardly paler on the narrow pos- terior portion, a little depressed but without an apparent furrow, the • denression almost lacking in the middle. Punctuation very fine, rather dense and irregular over the entire surface. Median sinuositv bordered bv a weak margin le?s accenuated and with very fine and superficial transverse wrinkles, that are not very visible, behind the middle of the anterior border without apparent depressions, although this median por- tion may be visibly limited on each side by a slightly depressed oblique line, irregular, appearing a little 'posselee.' "Scutellum slightly and rather uniformly darkened, with the basal angles and the summit paler, unpolished with the surface very finely granulated. "'^orium quite uniformly pale brownish, having the scutellum and embolium in large part pale, the external margin very narrowly blackish, slightly arcuated; margin of cerium behind the embolium very obtusely sinuated. Commissure of the clavus narrowly pale, near the middle shorter than the length of the scutellum; posterior margin of the corium with a semi-circnlar yellowish spot. Disc of the corium appearing cov- ered by a very fine pubescence almost clear. Membrane brownish con- colorous with the corium. "SegTnents of connexivum plainly visible behind the narrow elytral margin; unpolished, yellowish, without spots on the sutures, but with the extreme outer margin very narrowly blackish; posterior angles of the segments not projecting, following well the abdominal curve except on the last segment, who?e angle is a little prolonged behind, but scarcely acute at the tip on each side of the female genital pieces. 202 THE UNIVERSITY SCIENCE BULLETIN. "Body underneath yellowish ochreous, unpolished on the lower portion of the head, and the entire abdomen covered by a pubescence very dense and brilliant, almost golden. Legs pale, smooth, very brilliant. Labrum very obtusely angular in fi'ont, strongly punctured, yellowish with a strong brown tinge at the base; rostrum brownish, last segment darker. Texas." A. morvion Montd. Montandon, Bui. Soc. Sci. Bucarest, XVIII, No. 1, p. 48, 1909. "Oval, more attenuate toward front than rear; color of a yellowish ochre, little brilliant; very finely granulate on the head and pronotum, dull on the scutellum and the corium. "Head quite enlarged, a little narrower, eyes included, than half the greatest width of the pronotum, a little longer than the width of the intercular space, this latter very little convex, about three times wider than the width of the eye, pale yellowish with two brown spots sub- contiguous at the middle of the base. These two spots sometimes join in front and are prolongated longitudinally in a narrow brown band, which attains almost the anterior margin of the head. Eyes convergent in front on their anterior half, the inner edges posteriorly subparallel; little enlarged. "Pronotum deeply cut (scooped out) behind the head, this depression trisinuate, the median sinuosity behind the vertex larger and deeper, the two lateral sinuses narrower behind the eyes. Anterior angles of the pronotum sharp, lateral edges of the pronotum quite strongly arcuate with the posterior angle well rounded. Entire surface of the pronotum yellowish, paler on the posterior margin behind the transverse groove, quite plainly shown although vei'y superficial and narrowly interrupted in the middle; this groove sometimes slightly blackish. Disk of the pro- notum with six longitudinal, irregular, very poorly defined, little em- phasized, brownish bands, the two median slightly forked in front, leaving between them a clearer space, bipunctate on the posterior part of the disk; two others bent narrowly behind, one on each side beh'nd the eyes, attaining the middle of the disk, and two lateral ones, one on each side bounding the inner part of the margin: these brownish bands, for the rest, slightly visible, are without doubt very variable. "ScutePum clear brownish, with the lateral edges close to the basal aneles, and the apex pale. "Corium clear brownish like the scutellum with the external border of the embolium strongly arcuate, yellowish on the anterior two-thirds, more or less abundantly (largely) brownish on the inner edge and at the extremity; margin of the corium very obtusely sinuate, narrowing very sensibly the corium behind the embolium where it leaves the ab- dominal segments well exposed, these latter yellowish with the posterior external angle of each segment strongly acuminate in a sharp, rather long point directed backwards. Men^brane brown like the corium. "Under side of body pale yellowish, slightly ochraceous on the breast (sternum), sometimes slightly darker on the abdomen, the latter entirely pubescent velvety save the narrow band of the connexivum, which rema^"ns smooth. Legs pale yellowish with the extremi+y of the tibiae and tarsi narrowly and feebly darker. Length, 9.3 to 10.6 mm.; width, 5.8 to 6.2 mm. Utah." Also reported fi-om New Mexico. Atnbrysus signoreti Stal. 1862, Stal., Stet. Ent. Zeit., XXIII, p. 460. "Larger and broader than in the other species; length, 1.3.7 mm.; width, 8.8 mm.; coloration clear yellowish, with a great brown blotch on the elytra, which gives it a very easily I'ecognized appearance at first sight. The clavus pale yellowish, with a small brown Motch toward the base and another toward the tip. Elytral margin is obtus'^ly sinuate behind the embolium, this latter very broad, yellowish throughout its HUNGERFORD: AQUATIC HEMIPTERA. 203 width on the basal % ; brownish on the apical i/4 ; segments of con- nexivum brown on basal portion, yellowish behind. Transverse furrow of pronotum very plain, but somewhat superficial and a little interrupted at the middle; that portion of the pronotum behind the furrow very pale, smooth, having the punctuation very fine, concolorous and not dense.'" Reported from Colorado, New Mexico, Arizona and California. Ambrysus giittatipennis Stal. 1876. Stal., Enum. Hemip., V, p. 143. "Length, 13.3 mm.; width, 8.3 mm.; having the elytra darker brownish chan A. signoreti, Stal., having a small discal spot and a longitudinally elongated point at the middle of the corium yellowish; embolium yellowish on its entire width and on its basal two-thirds; brown on apical portion; entire c^avus brown except on the commissure where it is narrowly yellowish; elytral margin behind the embolium obtusely sinuate; seg- ments of connexivum brownish on the basal portion, yellowish behind; transverse furrow on the pronotum almost lacking; posterior portion of pronotum behind the furrow pale, finely scraped longitudinally, the scrap- ings well visible, less so on the posterior margin where the punctuation is very fine, concolorous and very dense throughout, or scrapings lacking." Found in Arizona. Arnbrysus puncticollis Stal. 1876. Stal., Enum. Hemip., V. p. 143. "Proportionately more slender than A signoreti or A guttatipennis. It is 13.7 mm. long and 8.2 mm. broad. Elytra and clavus entirely and uniformly darkened, having the commissure of the clavus narrowly yellowish and the embolium yellowish for its entire width on its basal half, and brownish on the posterior h?lf, excent a narrow yellowish border on the margin. Embolium less dilated than on the two species cited above; the external border of the elytra is not sinuate behind the embolium. The segments have the connexivum entirely yellowish, re- markable for the very acute teeth prolonged behind from the posterioi' angle of each segment. The transverse furrow of the pronotum is well marked, the posterior part behind the furrow pale, smooth, without appar- ent scrapings. Punctuation very fine and scarce but spread into very small rather dense black points." Found in Texas and Arizona. Ambrysus melanopterns Stal. 1862. Stal., Stet. Ent. Zeit., XXIII, p. 460. "Size, 11.8 mm. Icng; 6.7 mm. wdde. A little smaller than signoreti. guttatipennis, and puncticollis, but differs notably from these furthei' by the darker coloration on the pronotum, except a narrow clear band on the posterior portion by its less enlarged form and subparallel lateral margins; lateral margins of pronotum strongly arcuated and in front are as subparallel as their posterior portion; that is to say, the pronotum is net entirely narrowed in front on its entire length, the posteinor angles- are right angles, a little subrounded above. The hefd is smaller pro- portionately than in the preceding species cited, the width of the pronotum being proportionately equal in width, including the eyes, to that part of the width of the pronotum near it and the length a little longer than the width of the eyes behind. The latter are very convergent in front for their entire length, surface of head and pronotum punctured, with a small groove at the middle of the base of the head, having the appear- ance of an anterior prolongation of the longitudinal furrow. The body beneath and the legs are also les.s clear, yellowish brown." Found in Texas and Arizona. 204 THE UNIVERSITY SCIENCE BULLETIN. Amhrysus calif ornicus Montd. 1897. Mout., Verh. Zool. Bot. Ges. Wien., XXVII, pp. 12-18. "Form oval, head yellowish ochre, as long as wide between the eyes behind; interocular space with the lateral sides subparallel on the posterior half, progressively narrowed in front on the anterior half. Its width behind is equal to three times the transverse diameter of the eye on the same level. Surface of the head ver_ finely punctured, the punc- tuation a little less strong near the eyes. Vertex nearly smooth, finely rugulose, with the traditional spot of the genus a little broadened; very attenuated in front, "divided" at mid length, brownish, but very vaguely, poorly defined. "Pronotum a little longer than the head on the median line. The anterior angle almost right angles, a little acute, not acuminate. The lateral margins feebly arcuated, divergent behind on their entire length; posterior lateral angles broadly rounded. Transverse furrow vpry p^am, sunken, quite strong on the margin, narrowly interrupted on the median line; the punctuation fine and dense on the whole surface, a little more accentuated on the two anterior parts of the lateral margin. The anterior margin, which appears finely bordered between the eyes, is marked also behind the middle by fine transverse wrinkles that are rather crowded. The margin yellowish ochreous, rather broad; the disc and interior portion a little darkened, by the dots and small brownish blotches appearing poorly defined, the two m.edian longitudinal ones a little more visible, arcuated, converging in front and behind, but not con- fluent, allowing between them a pale median line, unspotted, narrowed in front, and behind, broadened a little beyond the middle. In front reach- ing the anterior narrow black border, and behind reaching the transverse furrow; the portion behind the furrow ver" pale yellowish, unspotted, finely and densely punctured. 'Scraped off' on a narrow margin, the length of the posterior border of the pronotum. "Scutellum yellowish brown, finely and densely punctured with the wrinkles very visible, little regular, and a little reticulated in places, especially toward the base. The principal wrinkle occupies the mid- length of the posterior half of the scutellum and is cut across a little before the summit by another transverse wrinkle. "Elytra very finely and densely punctulate, granulate, of a yellowish brown, quite uniform, with the margin of embolium clearer yellowish. Commissure of the clavus a little longer than the middle of the length of the scutellum. Membrane brownish, a little darker than the elvtra. Connexivum yellowish brownish, a little darker on a narrow band cover- ing the sutures; posterior angles of the segments almost right ang'les, very feebly acuminate, and not prominent. "Labrum very small, transverse, subrounded in front. Rostrum brown- ish, darker at extremitv. Under the body a large nart uniformly bro-^vn, legs yellowish, the femora paler than the tibiae; length, 7.2 mm.; width, '4.5 mm." Taken in California, as the name would imply. Amhrysiis pudicns Stal. 1862. Stal., Stet. Ent. Zeit., XXIII, p. 4G0. "Head and pronotum smooth; the latter with the sunken points scat- tered on the sides. Rather strong transverse wrinkles covering the slight depression at the middle of the anterior border of the pronotum. yellowish 'a dessins' the brown points les?= marked on the head and pro- notum; the transverse furrow on the pronotum well marked, the color clearer on the smooth region behind the transverse furrow. The pro- notum very much widened behind, having the lateral margins very con- vergent for almost then- entire length. Postero-la+^ral an^le quite broadly subtruncate, a little rounded. Eyes also quite strongly con- vergent for almost their entire length. The length of the head is much hungerford: aquatic hemiptera. 205 less than width. The interocular space behind and its width, including the eyes, is very much less than half of the ver large pronotum. 'E.ytra clear bi'ownish, a little darker on the middle of the disc. A small yellowish point on the middle of the posterior border of the elytra. Embolium yellow in all its width on the basal %,, brown at the extremity; elytral margin behind the embolium imperceptibly s.nuate, commissure of clavus a half shorter than the length of the scutelium; connexivum yellowish, hardly and very narrowly browned in the sutures of the seg- ments, with the posterior angles little prominent behind. Length, 7.7 mm. to 8 mm.; width, 4.8 to 5.2 mm. Mexico, Wyoming, California." Ambry sus heidemanni Montd. Moutandon, Bui. Soc. Sci. Bucarest, 1910, XVIII, p. 188. "Species very close as to form, mode of construction and design to A. mormon Montand, differing from it only m the size, a little more feeble. 8 6 to 10 mm.; in the lateral sides of the pronotum less dilated and less strongly arcuate without, as well as the dilation of the embolium a little less pronounced, the spines of the posterior angles of the seg- ments of the connexivum a little less strong and less projecting although always plainly visible, and in its deeper color, in design identical but more extended, sometimes nearly black on the head and pronotum; the scutelium and cormm uniformly more or less deeply brown, with the mar- gin of the embolium quite largely pale, poorly limited on its inner edge, the basai angles and the apex of the scutelium pale; the segments of the connexivum marked by a transverse black band covering up their basal thirds. "The longitudinal median b^ack band of the head quite enlarged, not reaching clear to the anterior border, but behind, it sometimes extends on all of the posterior part of the head from one eye to the other on a level with the posterior angles of the eyes. "Yellowstone Park in the puddles of water of the geysers. It is to the kindness of Mr. Otto Heiderr-an, the learned American Hemipterolo- gist, that I owe this species which has enriched my collection. I have also found a very dark specimen from the same locality in the material of the National Museum at Washington. "The darker posterior part of the vertex is more often marked by a median yellowish spot. The black blotches of the pronotum frequently form two more or less triangular figures on each side, these very unequal figures sometimes united, sometimes vrry vague, with only the contours ind'cated in places, but recalling always the same design as in A. mormon Montand., and always much Jess emphasizrd with deeper color. "The margins of the pronotum as also the posterior border always clear, the latter quite st^aieht. and marked sometimes by irregular black- ish spots." Taken in Wyoming. Genus PELOCORIS, Stal. 1876. Stal, Enum. Hemip., V, pp. 142-144. These bugs do not have the head so deeply set into the prothorax as the members of Amhrysus. Beak is very short. Posterior tarsi shorter than posterior tifcige. The latter outside and inside equally broad. Inferior side narrow, scarcely oblique. Eyes converging anteriorly, inner margin distinctly sinuated. Anterior angles of pronotum extending to the middle of the e; es. KEY TO SPECIES OF PELOCORIS. A. Ventral p^ate of the female genital segment "cleft" or emarginate at tip. Prothorax stout, densely punctate. (Length, 8.2 to 9.6 mm.). P. Caroline n sis. t 206 THE UNIVERSITY SCIENCE BULLETIN. AA. Ventral plate of female genital segment not emarginate at tip. Prothorax less densely punctate. (Length, 9 to 11.5 mm.) B. A dark streak on embolium, scutellum dark. P. biimpressus. BB. Not as above. P. femoratus. Pelocoris carolinensis Bueno, 1907. Bueno, Can. Ent., XXXIX, p. 227. "Head: Broader, including eyes, than long; front more or less re- motely punctuated and furrowed; width at base and at widest part sub- equal; eyes longer than wide, greateft width about one-third from the distal end; sinuate in the inner margin, converging toward the distal end more than toward the proximal end. Labrum broader at base than long; triangular in shape, with rounded apex attaining the middle of the third segment of the rostrum. Rostrum short, stout. "Pronotum about 2^/^ times as broad as long alcng the median line; broader at base than at distal margin; both basal and distal margins more or less sinuate ; edges curved regulai'ly from the eyes to the humeral angles, which are rounded; disc with indented lines behind the head, parallel to the anterior margin, the first line as long as the distance be- tween the e; es, and diminishing in length posteriorly, giving an obtusely triangular shape to the lined area, the remainder of the disk coarsely punctuated, caudad of the pronotal suture it is shagreened in wavy lines. "Scutellum about twice as long along the medial line; apex blunt; sides sinuate, shagreened. "Hemelytra narrower than abdomen, but extending to end of same. Membrane distinct, but merging insensibly into the corium. Embolium flattened and broadened marginally, extending beyond the abdomen. The three last connexival segments have prominent posterior angles. Entire hemelytra, including the membrane, covered with very short, sparse golden hairs. Mesosternal keel slightly raised, grooved longitudinally vdth hairs arising on either side, and nearly covering the groove. "Abdomen : Genital segments prominent in male, flattened and cleft in female. These segments are somewhat complicated, and no adequate description can be made without a dissection. "Pedes: First pair raptorial, with incrassate femora grooved for the reception of the tibiae, which are curved and furnished with a one-iointed tarsus, destitute of claws. Second and third pair cursorial, with normal femora and tibiae, with two-jointed tarsi, armed with moderately long, .slender claws. The tibiae are furnished with moderately long spines in two rows. "Coloration: Head flavous, with a dark median line of varying width, sometimes reduced to a triangle at the vertex, and at others entirely absent or very faint. Prothorax also flavous, the punctuations of the disk brown, the flattened outer margin much lighter in color; the area caudad of the suture, more or less variegated with perpendicular black lines of varying widths. Scutellum brown, the apex sometimes lighter in color, approaching to flavous; some individuals have lighter vermicula- tions in the disk. Hemelytra also brown, with lighter vermiculations, the ground color of var ing shades; the darker forms have two flavous spots on the corium at the edge next to the membrane, which disappear in the lighter forms. The embolium is testaceous, darkening caudad. The connexival segTnents are black posteriorly. The abdomen varies from testaceous to dark brown. The legs are concolorous except the spines, which are darker and black-tipped; the anterior legs are flavous, except the apex of the tarsus, which is dark. Labrum flavous; terminal segment of rostrum darker at the lip. "Measurements: Head — long., 1.5 to 1.7 mm.; lat., 2.6 to 2.9 mm.; long., 1.8 to 1.9 mm.; lat., 2.8 to 3 mm. Pronotum — long., 1.7 to 2 mm.; hungerford: aquatic hemiptera. 207 lat., 4 to 4.6 mm.; long., 1.9 to 2mm.; lat. 4.5 to 4.7 mm. Scutellum — long, (measured from prothoracic groove), 1.3 to 1.4 mm.; lat., 2.3 to 2.7 mm.; long., 1.4 to 1.5 mm.; lat., 2.7 to 2.9 mm. Insect — long., 8.2 to 9.3 mm.; lat., 5 to 5.5 mm.; long., 9.3 to 9.6 mm.; lat., 5.6 to G.l mm." Kan- sas, North Carolina and South Carolina ai'e localities from which this species has been taken. Peloeoris biimpressus Montd. 1898. Mont., Bui. Soe. Sci. Bucarest, VII, p. 285. Montandon and Champion both mention this as a variety of the species Peloeoris femorata, as set forth in the key. Stal says it is from North America. Peloeoris femorata, P. B. Palisot Beauvoris, Ins. Rec. Afr. Am., p. 'Jo 7. (The following from Uliler, 1884.) "Color more or less greenish tef^taceous. but after death it changes to a pale yellow, or horn brown. It has a black line across the base of the labrum; on the prothorax a dark brown quadrangular spot is seen on the middle next the front margin; each side of this is a wide triangle composed of scattered dots, flanked by larger and still more remote flecks, and vnth short, almost black lines in a series across the posterior submargin; while the lateral margins are broadly pale. The scutellum is rough, and almost covered by dark brown marbled lines. The slightly convex wing covers are livid brownish, with two pale dots inwardly next to the base of the membrane, and the base of the flat costal margin is broadly pale testaceous. On the venter is a faint trace cf silky hair, the sides of the abdomen are marked with six squarish, black spots, and the legs are ivory white, or yellowish. The anterior tibiae are strongly curved, tinged with piceous and there is a dot of the same color on the apex cf the pairs of posterior tarsi. It measures a little more than one- third of an inch." Distribution: "Mississippi, New York, New Jersey, Pennsylvania, Maryland, Florida, Illinois, Wisconsin, Minnesota, Michigan, Tennessee, Louisiana and Carolina." — Van Duzee. B. Biology o?' Naucorid^. General Notes. These flattened oval bugs are found amidst tangled growths of Nitella and other water plants. They seem to abound where there is a good shelter of water plants to which they cling. They swim through the water with an even, rapid gait, and catch their prey, which may consist of insects cast upon the water or any aquatic insects it can capture and overcome. Genus AMBRYSUS Stal. Habitat. Uhler says that Ambrysus signoreti dwells in the quiet waters adjacent to streams and in standing pools, especially such as are grassy. Another species is found in ponds in Dakota. No one seems to have noted the eggs or other biological matters concerning these insects. Genus PELOCORIS Stal. This genus, related to the European Naucoris of literature, has been more frequently studied. The notes on the European forms date back to an early time. De Geer noted their swimming ability and stated that they fly at night ; that they eat all sorts of little aquatic animals. Duf our described the eggs of two species, N. eimicoides and N. maculata. The 208 THE UNIVERSITY SCIENCE BULLETIN. latter species he said he kept confined for a long time, and that they lay their eggs toward the last of April "en les collant centre des brins de plantes aquatiques." Regimbart, 1875, said that N. cimicoides buried its eggs in plant tissues. Genus PELOCORIS Stal. The members of this genus and its European relative Naucoris of literature, are better known than those of Amhrysus. Frisch, 1727, under "Von der breiteren Wasser Wanze" says it is predatory and can chirp. Roesel, 1746, says that "Die breit leibige schwarz braune Wasser Wanze mit dem gelb eingefassten hinter leib und derselben Fortpflanzung" had an egg like the back-swimmer, only more rounded, and that the adults in August overwintered. De Geer noted their food and nocturnal flights. More recently we have Kirkaldy's notes on Ilycoris cimicoides and Bueno's history of Pelocoris femwata. Hihei-Tiation. As far as known all of these bugs winter as adults hidden in mud and trash. Uhler says that Pelocoins femwata hibernates at the bottom of pools and ponds, in places where it can find some depth of muck, and especially where reeds or water-plants remain rooted through the winter. Ovlpositioyi Roesel, 1746, Dufour, 1833, and Kirkaldy, 1905, describe the eggs of the European form cimicoides as placing its eggs upon stems. Regembart, 1775, said it inserted them in tissues of plants. In sup- port of Regembart, Wesenberg-Lund in "Fortpflarzungsverhaltnisse; Paa- rung und Eiablage der Suss wasserensekten" says: "In May, 1895, I found numerous eggs in the air spaces of leaves." Out in nature they were in old plant parts. From the ovipositor he thinks it is not likely that it just lays them on the plants. The American P. femorata, Uhler, 1884, says, glues its eggs to the sub- merged leaves and sprays of plants. Bueno, 1903, also finds this to be the case. He says, "The majority have been found attached axially to the stems or leaves of Ceratophyllum and secured to them by a glue in which the ovum is set and which surrounds slender stem or leaf to a variable extent." Incubation. Bueno has found the egg stage to last from 22 to 27 days. This was in early June. hluviher of Nymphal Instars: Five. Food Habits. The writer has fed them many different kinds of insects. They will also eat snails. Bueno fed his bugs one fly apiece each day. Behavior. These bugs like the dense cover accorded by water plants. In a series of "holes" in an intermittent creek bed near Coldwater, Kan.,* Naucoris carolinensis was taken in great numbers. These pools were spring-fed, and overgrown with a "water moss" (Nitella). This collection was made July 28, by the party under Mr. Reamer's direction. The description of the waters is taken from the collector's field notes. "The bottom was clay and sand, covered with 3 or 4 inches of soft, slimy mud, and above this was a great mass of moss. (Nitella.) We could not run the net through into it very far, but had good success pushing it into it as far as possible and then lifting and shaking the hungerford: aquatic hemiptera. 209 mass above the net. After prodding among this material and getting stung by Naucorids until a retreat was necessary, we would take the material to the bank and work it over, taking dozens on the way." The "sting" of this insect is indeed painful for a time, and it leaves a stinging, itching, burning sensation for some time, as the writer has found. DESCRIPTION OF STAGES. Pelocoris femoratax. The following is taken from Bueno, 1903. The writer has reared P. carolinensis in part, but has never had the time to describe the ma- terial: TAe Egg. Size. "Length, 1.4 mm.; width, .6 mm.; altitude, .7 mm. Shape. "From above, imperfectly oval; from the side somewhat flat- tened above, with a gradual rise toward the middle. The cephalic end is more rounded than the caudal, descending to the line of attachment with a shorter curve. This curve is somewhat depressed at the ex- tremity of the ovum, from which depression arises the micropylar boss. The form changes during incubation and just previous to emergence the ovum is larger and rounder than when first deposited." Color. "Translucent, pearly white when deposited, growing darker as development progresses. The surface is minutely punctulated in lines, punctures set close together, giving the appearance of meandering striations. As the time for emergence approaches, the character of the markings changes. The chorion is still punctulated, but at the same time engraved in distinct hexagons, produced by the punctulations." First Instar. Size "Length, 2.5 mm.; width, 1.5 mm. "Immediately after emerging from the ovum, the nymph is trans- parent, white and colorless, except that each abdominal segment has a broad, dark, luteous band at the connexivum. Also, the eyes are red and well-marked. The tarsal claws of the second and third pairs of pedes are dark and noticeable. The single claws of the first pair are colorless and transparent. The short rostrum is transparent pale luteous, darker at the tip. A seta issues from the posterior angle of each abdominal segment, at the connexivum, on the dorsal surface. About eight hours after emergence the insect is much darker in color. "In shape the young Pelocoris resembles nothing so much as the suctorial midnight prowler, at a superficial glance. Carefully examined, however, it is seen to resemble closely the adult in shape, allowing for the diff'erence in size and absence of wings. "When recently hatched its abdominal air coating is absent, and the young insect finds it difficult to reach the surface, which it succeeds in doing only by vigorous swimming. If it relaxes its efforts, it immedi- ately sinks to the bottom. Pelocoris swims back down when in this condition. "When still uncolored, the dorsal vessel can be plainly seen pulsating and the oily globules of the unabsorbed yolk moving in the abdominal cavity." Second Instar. Size. "Length, 3.25 mm.; width, .2 mm. "The appearance after the molt is practically the same as after emer- gence from the ovum, except that there is a dark, somewhat triangular- shaped blotch extending from the caudad margin of the thorax to the fourth abdominal segment, apparently produced by the abdominal con- 14 — Sci. Bui. — 1669 210 THE UNIVERSITY SCIENCE BULLETIN. tents. The pulsations of the dorsal vessel can also be seen in this instar under the same conditions as before, save that the yolk is, of course, totally gone." Third Instar. Size. "Length, 4.8 mm.; width, 3 mm." Fourth Instar. Size. "Length, 6.5 mm.; width, 4.2 mm. "Coloration and other peculiarities slightly more accentuated than in the preceding instars. I may here state that just previous to a molt the insect is very thick through, especially so in this and the succeeding in- stars, and looks fit to burst out of its skin, as it does." Fifth Instar. Size. "Length, 8.3 mm.; width, 5.5 mm. "I was fortunate enough to have the opportunity of observing the last moult in Pelocoris, which I will now describe from my notes taken during the process of the ecdysis. "The bug hangs from the surface, back up. The outer skin then splits along the thorax, and the scutellum of the emerging insect is seen. The opening enlarges as the insect gives rhythmical convulsive heaves. First the entire thorax comes out; then, with a jerk, the head. It now rests a moment, and in a short space again takes up its motion, withdraw- ing the body little by little from the cast-off skin. The dorsum, as yet uncovered by the still unexpanded ate and hemelytra, has a coat of air. The wings and hemelytra expand as the iftsect emerges, so that by the time it is entirely out they are fully developed, completely concealing the dorsum abdominis. It takes the insect about ten minutes to go through this final transformation. When it is entirely free, it turns quickly and hangs back down from the air-filled and buoyant cast skin for a moment, until the wings are perfectly expanded. Then it begins to swim about quite rapidly, coming to a rest once more, seemingly re- quiring something to hang to. There appears to be an undue amount of air under the insect's wings while it is in this condition, and it remains back up while swimming. The tracheal lining may be seen as Pelocoris emerges, connecting the sternum with the cast skin. "Pelocoris, immediately after the last ecdysis, is entirely of a beautiful light green-like aquamarine, including the hemelytra and the limbs excepting the tibias, which are dark from the swimming hairs. The eyes are a dark ruby-red. The insect gradually gTows darker, and about four hours after the change it is a mottled dark green. The full mature coloration is reached in about 12 hours." Stimmary. Bueno has presented the only account of the rearing of any Naucorid. The eggs of Pelocoris femorata were placed upon sub- merged plants. They hatched in about 24 days. The first instar lasts about 8 days; the second instar, 6 to 9 days; third instar, 8 days; fourth instar, 10 to 12 days; fifth instar, 16 days. A total, as Bueno tells us, of some 77 days for development. Nearly all stages may be taken in the summer time in a pool. At Coldwater, Kan., in July, all stages but the egg were noted. Family CORIXID^. A. Taxonomy of Corixid^. Family Characteristics. These medium-sized to small bugs are usually marked with bars of yellow and brown. The body is flattened above, and the head overlaps the thorax dorsally. The most peculiar thing about them is the structure of the beak, which is very short, scarcely if at all hungerford: aquatic hemiptera. 211 distinguishable from the face, the opening to the mouth being on the front of the so-called beak. The front tarsi are also peculiar, being 1-segmented, flattened and fringed with strong bristles. They are spoon- shaped, or palaeform. The middle legs are long, slender, and end in two long claws. The hind legs are flattened and fringed for swimming. Historical Review. "Corixa" means bug, and is a fitting name for these water bugs, for they have a buggy smell. They have been known by this name since Geoff'rey, 1762. Borner, 1904, in a study of the mouth parts of this group, separated these bugs off as a separate suborder, Sandaliorrhyncha. The other suborders he called Auchenorrhycha (Homoptera), Heteroptera and Conorrliyiicha. Bueno even gives them ordinal rank, but Reuter reduces the Sandaliorrhy^ncha to a series under the Heteroptera. Key to Genera. Doctor Abbott, of Washington University, has been working for several years upon a world monograph of these bugs. He expected to complete the systematic part two years ago, but the inter- ruptions of the times have kept him from so doing. It is a most difficult group, and it is to be hoped he can give the workers a practical means to determine their material.* For the present the writer gives a tenta- tive key to the genera. He knows of too much synonomy to waste time on specific keys to the large genus Arctocorixia, which contains some fifty species, for instance. Only the males are keyed out satisfactorily. The females look much alike. KEY TO GENERA OF CORIXID^. Males. A. Scutellum covered by pronotum only at the anterior margin, Pro- notum roundly emarginate behind. Tenagobia Bergroth. AA. Scutellum covered (except sometimes at posterior angle) by pro- notum. B. Strigil absent. Pronotum and tegima more or less rastrate. Conspicuous black spot usually present on hind tarsi. Callicorixa White. BB. Strigil present. C. Strigil on left side. Pronotum and tegmina smooth, shining, asymmetry on left side. Corixa Geoff. CC. Strigil on right side. D. Head of male sharply acumiate. Asymmetry right. Strigil small. Ramphocorixa Abbott. DD. Head of male normal. E. Hind wings usually aborted. Palar pegs in two series, or one crowded row. Palmocorixa Abbott. EE. Hind wings normal. Stridulatory palar pegs well developed, curved in single row. Arctocorixa Wallen. * Doctor Abbott has now given up this work, and the writer has the task of completing Doctor Abbott's work. He is permitting the keys to stand for the present as first written. 212 THE UNIVERSITY SCIENCE BULLETIN. Females. A. Scutellum covered by pronotum only at the anterior margin. Pro- notum roundly emarginate behind. Tenagobia. AA. Scutellum covered (except sometimes at posterior angle) by pro- notum. B. Face flattened, foveate, palse deeply furrowed. Ramphocorixa. BB. Face convex. C. Hind wings aborted usually. Pahnacorixa. CC. Hind wings normal. D. Pronotum and tegmina smooth, shining. Corixa. DD. Pronotum and tegmina not smooth and shining. E. Hind tarsi pale, fringing hairs dai'k in some species. Arctocorixa. EE. Hind tarsi usually marked by conspicuous black spot. Callicorixa. Genus TENAGOBIA Bergroth 1899. Minute species never over 5 mm. long. The scutellum is covered by the pronotum only at the anterior margin, and the pronotum is roundly emarginate behind. One species, Pacific. Genus CALLICORIXA White 1873. Three species of bugs, all from Alaska, are in our list. The scutellum is covered, except sometimes at the posterior angles by pronotum. Strigil is absent. A stridular area is present. The hind tarsi usually marked conspicuously with black. Three species, all from Alaska. Genus CORIXA Geoffrey 1762. Pronotum and tegmina are smooth and shining. The male asymmetry is on left side. Strigil is present. Scutellum is covered (except sometimes at posterior end) by pronotum. Palar stridulator never with bristles, al- though the "pegs" may be elongate. Genus RAMPHOCORIXA Abbott 1912. Peculiar in the sexual dimorphism of the head, the male very acumi- nate, the female normal. See plate XXVII. The asymmetry is right and strigil minute. The pronotum is lenticular rastrate. The male palae are dorsally deeply cleft, much longer than tibise, and terminated by a long serrated spine. Femur with large stridular area or of minute spines. Face of the female foveate. Genus PALMOCORIXA Abbott 1912. "Body elongate, tegmina tapered posteriorly, with vermiculate mark- ings. Male palse thin, plate-like, pegs variable. Large stridular area on femur. Meta thoracic wings aborted in both sexes (usually*). Male * The writer's insertion. hungerford: aquatic hemiptera. 213 asymmetry and strigil dextral; fifth tergite entire, sixth divided." — Abbott. The above description is taken from Can. Ent. for April, 1913. This is a revision of the original generic diagnosis. To date there have been described two species separated by the following table. KEY TO SPECIES. a. General facies dark. Tegminal lineations complete. Front femur of female oblong, 2V^ times as long as wide. Palar pegs of male 24-33* in crowded row the length of pala. P. bueuoi Abb. AA. General facies light. Tegminal lineations incomplete. Front femur of female trapezoidal, two-thirds as wide as long. Palar pegs of male in two rows confined to base of pala. P. gillettii Abb. Palmacorixa buenoi Abbott. Can. Ent., Apr. 1913. "Similar to P giUettei in size and appearance, in the flattened short pronotum, and large head, with prominent posterior angles. Dark yellow to smoky brown, and much darker than giUettei. The tegminal lineations are complete, more or less inosculated and confused, but without a marked tendency to longitudinal seriation. Lineations of clavus complete, i. e., not eff^aced on the inner anterior area as in giUettei. Head smoky brown; its length 1% in the width of the male, 2V4 in the female; interorbital width twice in the head length in the male, 1% in the female. Male fovea more prominent than in giUettei, reaching the middle of the eye, and clothed with delicate depressed hairs. Pronotum flattened, margined, lenticular in outline, evenly rounded posteriorly, dull and minutely rastrate, with % approximately parallel lineations, which are more or less broken, the lineations about as wide as the yellow interspaces. Posterior margin brown. Claval lineations delicate, vermiculate and inosculate, covering the whole clavus, fused externally to form a more or less definite oblique line parallel to the corio-claval suture. Clavus rather infuscated and clouded across the middle third. Markings of corium similar to those of clavus, running without interruption over the membrane ; inoscu- lated, but scarcely interrupted, sometimes fused into one or two rather indefinite longitudinal lines, which do not extend beyond the embolium. Surface of clavus and corium rather dull and rough, the clavus usually rastrate, the corium merely punctate. Margins of embolium and of clavus elevated. Lower surface and legs pale; posterior tibia fringed with brown hairs. Metaxyphus very short, acuminate. Strigil rounded, 5 striae, diameter 0.1 mm. "Male pate cultrate, somewhat produced at the base, the length three times the greatest height. Pegs blunt, elongate, 24-33 in number. The distal ones are somewhat longer and crowded, and may be displaced into two irregular rows. The main row begins midway the base and rises in a curve after the first half dozen pegs ; then follows the upper margin, but at some distance from it. A second row of peg-like spines along the lower margin, about iy2 to 2 times the length of the pegs. Tibia sub- globular, about as high as the pala. Femur oblong, a little less than twice as long as wide, the stridular area covering the proximal half and consisting of short spines set in transverse rows. Female palas cultrate, not produced at base, slightly more than three times as long as wide, broadly joined to the tibia. Tibia rounded oblong, tapered proximally, twice as long as high. Femur oblong, 2V2 times as long as wide (the width at base in P giUettei is two-thirds the length) with stridular spines* on the surface as in P. giUettei. Second leg, Femur 2V2 times * Number of pegs exceeds this in one series examined by the writer. * Through a lapstis calami these are called "spines" in the description of P. r/iUettii (1. c, p. 339). 214 THE UNIVERSITY SCIENCE BULLETIN. the length of the tibia, the latter equal to the claws, and IV3 the length of the tarsus. Length 5% to 6 mm.; width across pronotum ll^ mm. "Types 2 (male) and 2 (female), from White Plains, N. Y., collected in August and September by J. R. de la T. Bueno. Other specimens have been examined from Washington, D. C. (coll. W. L. McAtee) Oglethorpe, Ga. (coll. T. C. Bradley) Hadley, Mass., (coll. C. A. Frost) and Valhalla, N. Y. (coll. Bueno). The species, therefore, appears to be distributed pretty widely up and down the Atlantic coast of the United States. "Variation. Some twenty specimens have been examined in addition to the described types. These individuals show a wide range of varia- tion, such that the extremes would seem to belong to different species were it not for the intergradation. The writer has been unable to find any constant character, however, which would serve as a basis for discrimina- tion. The smallest (White Plains) measures but 4^/4 mm., the largest (same locality) 6V^ mm. The tegminal surface may be smooth and polished, or dull and rastrate, the lineaticns varying from the regular complete lines of the type to interrupted and confused markings, re- sembling those of P. gillettei; the inner angle of the clavus, however, is never bare of lineations. Pronotal lines 6-9, either entire or much broken and confused. The index of pronotal width divided by pronotal length ranges from 2.22 to 2.60 in the 5 , and 1.79 to 2.73 in the ^ ; that of the head width divided by the interorbital width ranges from 2.87 to 3.57 in the 0 and from 3.60 to 4.20 in the j ; that of the head width divided by the head length from 2.07 to 2.60 in the j and from 1.68 to 2.33 in the ^ . In the male the palar pegs are sometimes crowded into two rows at both ends of the series. The absence of functional wings in both sexes in this genus certainly interferes with the rapid dispersal or mix- ing of individuals from adjacent localities, and thus brings about a partial segregation which would preserve and intensify aberrant varia- tions. This possibly explains the very unusual range of variability above described." Palmacorixa gillettii Abbott. Ento. News, Vol. XXIII, p. 337, Oct. 1912. "Head pale yellow, vertex usually carinate, posterior angles rather acute and produced backward. Posterior margin emarginate. Inter- orbital space (posterior margin) about twice in the median length of the head in the male; one and a half times in the female. Inner margins of eyes parallel in facial aspect. "Pronotum lenticular, with a more or less definite median keel, rather strongly margined, the margin being marked by a narrow line of brown, the anterior line incised to correspond with the emargination of the head. Color, yellowish, paler at the sides, with eight to ten delicate broken and confluent lineations, some of the most posterior of which join the mar- ginal line. Surface of pronotum polished, minutely rastrate; it requires a compound microscope to resolve the rastrations. "Tegmina polished, nonrastrate, light yellowish with brown mark- ings. The latter are quite variable, usually not displaying the familiar cross-barred effect of the majority of the species in the family. Clavus more or less immaculate toward the inner angle as in mercenaria Say, the markings reduced to a more or less definite diagonal stripe following the direction of the corial suture. The inner edge of the clavus is margined with brown, and between this and the diagonal stripe mentioned are nu- merous lineations, ranging from isolated flecks in some individuals to interlocking and cross bars in others. Embolium immaculate, its inner edge strongly margined. Corium and membrane with vermiculate and, inosculate brown markings, usually arranged in two rather indefinite longitudinal stripes. A dark fleck on the outer edge of the membrane. "Metathoracic wings aborted in both sexes to a rudiment which ex- HUNGERFORD: AQUATIC HEMIPTERA. 215 tends from thorax to about the level of the third abdominal segment. Strigil ovate, about 0.3 mm. long, by 0.2 mm. wide, transversely placed, with 6 to 7 striae. Legs and entire under surface yellowish white. "Male palse very strongly compressed, plate like, the lower edge straight, the upper edge parabolic in outline; the surface covered with fine depressed spines. Toward the lower edge, next the tibial joint, are found the "pegs" in two rows, 5-6 in the upper row, 9-10 in the lower. These two rows seem rather sharply differentiated from the rest of the spines covering the face of the pala, yet it would seem to be not im- possible that the whole surface may function in stridulation. The lower edge of the pala is fringed, but there is no terminal spine. Tibia globular, about one-fourth the length of the pala. Femur oblong, as long as the pala, its width about one-half its length. Stridular area large, consist- ing of numerous rows of minute spines. Female palje short cultrate, triangular in section, the length a little less than three times the greatest height. Tibia rounded oblong, about as wide as the pala, its length a little more than twice its width. Femur trapezoidal in shape with a dis- tinct area of strong spines analogous to the stridular area in males. "Second leg: Spines about equal to tibia in length, the latter one-half the femur. Tarsus slightly shorter than tibia. Third legs: Femur and tibia subequal and about four-fifths the tarsus. Metaxyphus short, acute. "Length, 6 mm. ; width across pronotum, 1 Vo mm. "Described from three males and thi'ee females from Fort Collins, Colo., collected in May and June by Prof. C. P. Gillette, to whom the author is indebted for the specimens. Superficially the species resembles calva Say, vdth which it possibly has been confused. It is considerably larger than Say's species and structurally very different from any other Corixid with which the writer is familiar." Genus ARCTOCORIXA Wallen 1894. The scutellum is covered except sometimes at posterior angles by pronotum. Tegmina without short black hairs. Asymmetry on right side. Palor stridulator never with bristles although the pegs may be elongate. Strigil present. B. Biology of Corixid^. General Notes. The water boatmen spend most of their time upon the bottom of the pool, where they feed upon the flocculent deposits of ooze containing diatoms, desmids, filamentous algae, oligochetes, etc. This food they gather with their front legs. They fasten their yellow top- shaped eggs to submerged brush or vegetation. One species places its eggs upon crayfish. The adult males chirp by rubbing the front tarsi against the beak or the femur of opposite leg. The writer submits herewith notes on but three species. He has reared a considerable number, but intends to report upon them in an extended monograph of the Corixidje now in preparation. The three species chosen represent three genera and illustrate the diversity of habits in the group. Rnwphocorixa acuminata Uhl. Doctor Abbott has written two papers on the biology of this species, one dealing with the manner of its oviposition and the other some notes on the life history, together with a description of the instars. It is indeed a remarkable form and Doctor Abbott described it as a new genus and new species when it came to his hand. He has since decided that it is the same as Arctocorixa acuminata Uhl., though the bug is much more 216 THE UNIVERSITY SCIENCE BULLETIN. readily recognized by Abbott's description and figures. The dimorphism of the sexes is perhaps the most remarkable in the entire family, the head of the male being decidedly acuminate, while that of the female is normal. See figs. 2 and 3 on plate XXVIII. Habitat. This form is found in the muddiest of ponds in the middle west. No waters appear to be too stagnant for its abode, which may account for its strange habit of placing its eggs upon the carapace of crayfish. Hibernation. Females of this species have been taken by the writer in Kansas in winter collecting. Mating. Mating takes place in the same manner as with other Corixids and at about the same time. Oviposition. In a paper entitled "An Unusual Symbiotic Relation be- tween a Water Bug and a Crayfish," Doctor Abbott gives an interesting account of the strange habits of egg deposition of this species. The paper is accompanied by two photographs of crayfish laden with Corixid eggs. He describes the condition very accurately, noting that the re- ception of each egg cup, *'as if the affixing of the egg had either softened the chitin somewhat, or had taken place before the hardening subsequent to ecdysis had been completed." Forbes, in 1876, sefems to have been the first to note that crayfish carry Corixid eggs. He suggested that they were probably the eggs of Corixa. alternata Say, but since we know the habits of both species in question, it was without doubt Abbott's Ramphocorixa balanodis. While both Doc- tor Abbott and Doctor Forbes failed to find these eggs anywhere else in the water, the writer has occasionally found them attached to sticks and floating plants, but never in numbers. There is indeed a striking inti- macy between these animals. Doctor Abbott attempts to explain the "symbiosis" as follows: "The investiture of eggs commingled with debris certainly renders the crayfish less conspicuous and it probably profits by the arrangement in much the same way as do various shore crabs which are decorated with sponges, algae or coelenterates. Whether the water bug improves its chances against racial extermination by the adoption of such a pug- nacious protector it may be too much to assume, but at any rate, what- ever the utilitarian value of the habit, it must be of the same nature as that which obtains in the widely distributed genus 'Zaitha." In a study of a considerable series of crayfish carrying various num- bers of eggs, the writer believes he has found a plausible explanation for the unique support employed by this Corixid. A casual examination of many Cambarus immunis, together with the tabulation of the distri- bution of eggs upon a representative series, herewith represented, leads to the belief that it is a matter of aeration. An examination of the table shows that there was a marked tendency fo- the first eggs to be placed low on the pleurites of the first abdominal segment. That, after many eggs were thus deposited, they were placed upon the carapace near the lower posterior margin. In one case, num- ber 5, there were 13 eggs on top of the carapace behind the eyes. When we study the respiration of the crayfish we find that a current hungerford: aquatic hemiptera. 217 w < Pi a R o CM O m 2 o o 1 1 ■a -i til "3- Place .... No. eggs. . ft Place. ... No. eggs. . d e2 Place. . . . No. eggs. , c a 15 a 'a 0 -a -i !? a3 ■3. Place.. . . iJ No. eggs.. c^ c Place.... l-J l-J No. eggs. . CO c-1 c. 0 Place. . . . No. eggs. . a bO 0 CO £ 0 -cJ ■s 0 a5 Place hJ K^i kS No. eggs. . ■* CM ■a< ' 5. Place ... hJ ij No. eggs. . CD W cq 0 Place . . . No. eggs. . First abdominal segment. .4J "^ p. Place J hJ hJ hJ »J J h^ iJ ►-5 hJ No. eggs. . ^ 0 ?] C5 — ■ — VD t^ CO Oi □. Place.. . . hJ hJ H^ hJ J J ^J hJ iJ No. eggs.. t^ Ci ^ ■r}' 50 I-- -^ 00 CM d Place. . .. No. eggs.. 0, 0 Place.. . . No. eggs. . C<1 -^ 0 •^ bc-o 5'^ Place. . . . : S p- No. eggs. . 00 CO CO CI d 0 Place No. eggs. . « Sex of cravfisl 1 . . 1 1 Length crayfish in inches . c^i M c^^ ^ c c 1 c ^ ^ t* If 5 li 5 t- a 3 c i C C^ i 218 THE UNIVERSITY SCIENCE BULLETIN. of water is kept passing beneath the carapace and over the gills. This water enters the gill chamber from the rear, passing directly by the abdominal pleurites. The current would be strongest at the first ab- dominal pleurite, and it is just here that we find the first, eggs. Figure 1, plate XXVIII, attempts to illustrate this point. The eggs, therefore, are placed upon the crayfish in the region where there are the best chances for aeration. If only crayfish heavily burdened were examined, it would not be so apparent, but even the photographs of the one shown by Doctor Abbott, which must have carried some 3,000 eggs, the back of thorax and ab- domen were comparatively clear. On the other hand, if the oviposition be light, it is obvious at once that there is a choice of position in placing the eggs upon the crayfish, and that this choice is coincident with the region bathed with the freshest water. The crayfish studied were taken from the Griesa Pond on June 15 and 17, and from the Race Track pool, July 5. The series studied by Doctor Abbott were taken early in July and began to hatch the 8th. Incubation. No eggs have been observed from oviposition to hatch- ing, but since the eye spots show up about four days before hatching it would indicate that incubation is about the same as with other Corixids. Hatching. The process appears to be the same as with other Corixid nymphs studied, the egg splitting back in from six to eight lobes. Behavior of Newly Hatched Nymphs. The nymphs, upon hatching, keep close to the bottom and prefer the dark, according to Doctor Abbott. Their safety depends directly, in these early hours, upon inconspicuous- ness brought about by their transparency and tendency to remain quiet. Doctor Abbott's specimens were reared in a large zinc-lined aquarium, having a superficial area of 30 to 35 square feet. His attempts in small jars failed. The writer has carried a generation through in a common glass battery jar vnthout attention, the jar being prepared beforehand. While Doctor Abbott noted that mortality was high from third instar on, many being found dead in the morning, when combined with the observation that the nymphs were more active dull dark days, led him to believe they were more active at night. It might be added that there is a possibility that the activity or tendency to come to the surface at such times may be due to the need for air. On bright days the water plants add quantities of oxygen to the water, and it has been observed that they can be forcibly retained submerged in vessels containing water plants for longer periods than in clear water. In boiled water they become distressed rather quickly. Number of Instars. There are five nymphal instars which have been described by Doctor Abbott. The description of the egg and nymphal stages is taken from his paper. DESCRIPTION OF STAGES. The Egg. "Length about .9 mm. Breadth about .4 mm. Shape elongate-oval, bilaterally rather than axially symmetrical, i e., one side nearly straight, the opposite strongly curved. Colour grayish yellow (later stages only hungerford: aquatic hemiptera. 219 were observed) ; the surface ornamented with a delicate tracery in the form of interlocking hexagons like a honeycomb or the facets of a com- pound eye. The egg is fastened in a sort of shallow cup which is of a leathery texture and dark brown in colour. The distal end, through which the nymph emerges, is provided with six to eight short lobes arranged in a circle. The appearance of the whole egg is much like that of a minute Grantia sponge. Dufour described the eggs of striata and hieroglyphica as acuminate at the free end and placed on a pad. White speaks of the eggs he describes as pyriform and attached at the broader end. He does not mention the pad or cup, nor does Heidemann, of Corixa mercenaria. It would be of interest to discover if there is a difference in this regard between different species of Corixids or whether in some cases the pad or cup has merely escaped observation." It may be added that the ovum has a transparent button and tip, while the body of the egg is yellow. First Ins tar. "Length, about 1.15 mm. Width, about 0.55 mm. General appearance of adult, but wider in proportion to length. Head about three times as wide as long (dorsal aspect) ; distance from vertex to tip of beak about equal to the width between eyes (ventral aspect). Eyes promi- nent and conspicuous, deeply pigmented, facets relatively large. The beak is apparently 4-jointed, rather broad and conical. The black tips of the mandibles and maxillae project slightly between the two halves. The former are somewhat shorter than the latter, curved, with minute serrations at the tips, and may be seen to extend into the head apparently up to the level of the eyes. "The antennae are 2-jointed, inserted far down toward the beak, the last joint about one-third the interorbital width in length. Tarsi all 1- jointed. Those of first leg, when at rest, curved over beak as in imago. First tarsi triangular in section, about one-third as long as those of third leg, 3% times as long as broad, oblong-triangular, broadly rounded above, the comb of bristles prominent. Tibia of second leg three-fifths the length of tarsus and squarish in section with the anterior angles armed each with a row of short bristles. Intermediate tarsus nearly eight times as long as broad, with a ventral row of long bristles and several rows of much shorter ones; tarsal claws weak, variable in length. Third leg sparsely bristled, tarsal joint slightly longer than the tibia or the femur, which are subequal. Body a little less than twice as long as broad, the posterior angles not so truncate as in later instars, provided and armed each with a half dozen rather long bristles. Lateral margin of body with bristles on posterior half only. "The tracheal system is comparatively simple, consisting of two longi- tudinal trunks sending off laterals in each abdominal segment, and one stout branch to each leg. Anterior branches supply the brain and the eyes." Second Instar. "A marked increase in size is noticeable, the length being now about 1.9 mm., and the width about 0.9, roughly one-half as much. Head strongly convex, the frontal margin with a row of rather long bristles, longest in the middle, shorter toward the eyes. Posterior border deeply sinuate or arcuate. "Prothorax about as long as mesothorax, the two together a trifle longer than metathorax; the contour of the two together forming a narrow oval. Posterior margin of metathorax straight, anterior margin concave; its median length about equal to that of head. Abdomen trun- cate, 7-jointed, last joint about one-half as wide as first joint, termi- nated by two groups of rather long setae at the angles. "Tarsi all 1-jointed. First tarsus fringed with moderately long 220 THE UNIVERSITY SCIENCE BULLETIN. setae, about equal to tibia in length. Second legs; tarsus equal to tibia, both together about as long as femur. Third legs with femora, but slightly flattened, tarsus nearly as long as femur and tibia together, clothed with setae, these longest at the joint, becoming much shorter distally. Colour very transparent. A median grayish line on thorax." Third Ins tar. "Length, 2 mm. Width, 1 mm. Head as before. Eyes a little more than one-fifth the head-width in width. The wing-pads first appear; about three-fifths the length of thorax, sparsely hairy. Thorax one- half as long as wide. Abdomen as before, fringed on the sides by rather long setffi, the posterior angles with conspicuous tufts. Ventral surface sparsely pilose. "Tarsi all 1-jointed. The whole first leg about equal in length to the femur of second leg. Tarsus about three times as long as broad, termi- nated by a sharp spine. Second legs slender; tarsal claws as long as tarsus, other joints as in third leg, all feebly setose. Third legs ; tarsus 1 Va times the tibia, the latter equal to femur. Tibia and femur together about equal to femur of second leg. Abdomen strongly truncate." Fourth Instar. "Length, 3mm. Width, 1.2 mm. Very much more pigmented and less transparent than previous instars. Posterior margin of head, pos- terior angles of eyes, and posterior margin of thorax fuscous. Anterior margin of thorax and inner edge of wing-pads with rather dense brownish-black hairs. These together with the pigmented posterior mar- gin of the thorax form a square; a median patch of brown hair joining the band on the anterior margin. General surface of thorax smoky brown with narrow median clear line, and a paler transverse band in the middle. Head pale brown with darker shading on vertex. Whole dorsal surface of thorax and abdomen sparsely hairy, the abdominal segments faintly indicated by transverse brown stripes. A median longi- tudinal white stripe one-third the body-width in diameter runs the length of the dorsal surface of the abdomen. Within this is a series of large pale brown blotches, one on each segment, the third and fourth of these with a distinct crescent of chestnut brown, marginal third of abdomen smoky, fringed with cilia, but these less conspicuous because of the general hairiness of the body. The wing-pads hardly extend beyond the thorax. "Tarsi all 1-jointed. First legs as before. Second leg with femur as long as width of head, equal to tibia and tarsus together. Claws one-fifth longer than tarsus. Third leg with tarsus equal to width of head, feathered with dense hairs. Antennse one-half of the length of tarsus of first leg. Interorbital space two-thirds the width of head, and equal to three-fourths the length from vertex to tip of beak." Fifth Instar. "Length, 3.8 mm. Width, 1.4 mm. Dorsal marking as in previous instar, but more intensified. The two median dark brown marks of third and fourth abdominal terga oblong, surrounded by a larger oblong one of smoky brown. Hairy covering of wing-pads and thorax conspicuous, the median patch of the anterior border extending more than one-third the length of thorax down the median axis. Wing-pads extend half way to third abdominal segment. Beak brownish, with short pubescence. Legs pure white, antennae no larger than before, but fringed with short cilia. Tarsi of first two legs one-jointed; those of third leg two-jointed, otherwise legs as before. "In comparing the various larval stages one is struck by marked in- crease in the size of the eyes relative to the size of the head as de- velopment proceeds. Another point is of great theoretical interest. As is hungerford: aquatic hemiptera. 221 well known, there exists throughout the group an extraordinary sexual dimorphism, such that the uninitiated might be led to class males and females of the same species in different families, so great is the dis- similarity in structure. It is of interest to note that the larval stages up to the last instar, with respect to those structures (palse, frontal fovea, asymmetry of abdominal segments, etc.), that exhibit this dimorphism, are entirely of the female type. The writer has dissected the much larger Arctocorixa harHsii Uhl, during the last moults, and has found the same thing to be true. A specimen in the fifth instar just ready to moult may easily be 'shelled out' of its cuticle and, if a male, the irregular arrangement of the abdominal segments will be found fully developed, but entirely concealed by the regular and symmetrical ar- rangement, characteristic of the females and larvae." Summary . Ramphocorixa acimiinata Uhl., known in literature and in Van Duzee's checklist and catalogue as R. balanodis Abb., winters as adult, places its eggs upon crayfish in such a manner that they receive the maximum amount of fresh water. The species occurs in muddy ponds in the middle west and its eggs are found in June and July. Each instar requires about a week, adults being produced in some seven weeks after the deposition of the eggs. Palmacorixa buenoi Abbott. There have appeared life history notes on species of but two of the six genera of the family Corixidae in this country. The first of these was by Doctor Abbott, and dealt with the only species in the genus Rhampho- corixa. The second was a report upon Arctocorixa alternata by the writer. This present account considers the biology of a species of the genus Palmacorixa. There are only two species reported for this genus, P. gillettii Abbott, found in Colorado, and P. buenoi Abbott, reported for the eastern states. This latter species came to the writer's attention while collecting water bugs at the Field Station, Ithaca, N. Y., on January 19. The day was very cold and the net stiffened as soon as it came in contact with the air. All still waters were frozen over solidly, but on the south side of the station there was a cement walled ditch containing about two feet of water supplied from a strong spring. Near the spring there was but a thin coating of ice, easily broken. Amongst the dense tangles of Elodea many active Corixid adults of several species were taken. This was to be expected, for all the water bugs were supposed to pass the winter as adults. However, among this afternoon's catch were many strikingly marked nymphs of some Corixid, all in the same instar. This seemed so unusual that these nymphs were followed in nature and in the laboratory until the entire cycle was estab- lished. So exceptional in its seasonal appearance is this form that no attempt is made to follow the usual order in the discussion. Collecting throughout the remainder of the winter and early spring established the presence of only the nymphal form of this species. These nymphs were abundant in the pool above mentioned, in the slack waters of Cascadilla creek, known as "Dwyer's" pond, and in the quiet strip of water called "Bool's Backwater," which connects Bool's brook with Fall 222 THE UNIVERSITY SCIENCE BULLETIN. creek. Since this Bool's Backwater was surveyed nearly every day from earliest spring to near the end of the season, the field notes taken in that connection afford a splendid outline for the development of this species in nature. It would appear that this boatman prefers permanent and quiet but fresh waters, perhaps best suited to its needs if some part of the body of water has depth. Along the shores of Beebe lake, only a few hundred yards distant from Bool's Backwater, a large form of this same species was found. The two bodies of water are connected by Fall creek, and the presence of two very distinct sizes seems remarkable. The larger form was never taken in Bool's Backwater, but a very few of the smaller form were taken in Beebe lake, along with the much more abundant large variety. Aside from the decided differences in size, the females are much alike. The males, however, present differences in the arrangement of the palar pegs and in the strigil and abdominal segments. From the material examined, it would seem that the pegs of the smaller form show a greater tendency to crowd out of line, thus forming two lines at one or both ends of the series. The smaller species has a larger, coarser strigil than the other, while the right lateral margin of the abdominal segments are more spinously produced in the larger form. These points are figured on plate XXVII, which see. Life Cycle in Nature. Overwintering nymphs were so abundant in Bool's Backwater and other species so rare that it was determined to follow the development of this unusual Corixid in this way. Collecting in early April brought forth only fourth instar forms. April 18, while the waters were still quite cold, the A. alternata present were mating and the P. buenoi were still in their overwintering stage. There was no change in matters until May 2, when a few in the fifth instar were taken. A count of one catch showed 73 per cent still in the fourth instar. It was on this date I noticed the May fly nymphs, which I have called the "scooter." This nymph is mottled, with about the same shades as a Corixid nymph, and is fully as inconspicuous. They occupy the same foraging grounds, and it is the protective resemblance and agility in both that insure their perpetuity in the world. On May 9 adults of A. alternata and the over- wintering nymphs were notably "mited." A collection of the A. alternata showed 85 per cent of them to carry the water mites. By May 19 most of the nymphs were in the fifth instar. May 21, 97 per cent of the catch were in fifth instar. In a count of 300 nymphs, only one per cent of them were infested \vith mites, and in this case only one mite on each. Those infested with mites were delayed in molting. June 4 was a fine, warm day, following two or three before it, and the first adults of the P. buenoi were taken. There were 95 per cent still in the fifth instar. The first instar nymphs of A. alternata were taken on this date, which indicates the ease with which the overwintering species could be followed up to this time. Most of the adults of P. buenoi were new fledged, as indicated by the softness of their integument. In fact, some were creamy yellow, showing that transformation had just taken place. Another item of hungerford: aquatic hemiptera. 223 interest in regard to these early adults is that out of a catch of 29 speci- mens 22 of them were males. If percentage for so small numbers is worth anything it indicates that 79 per cent of those taken at this early emergence were males. In a collection made on June 8 were found 33 specimens — 12 fifth in- star nymphs, seven females, and thirteen males. It is worth noting that the mites that had been clinging to the fifth instar nymphs were molting to the free state at this time, just ahead of the time for these nymphs to become adult. June 13 found most of the individuals adult. One nymph in perhaps 200 adults. Eggs began to appear about June 20, which was a week later than noted in the laboratory. Most of the eggs had hatched July 11, and in a catch made July 13 there were: 4 first instar P. buenoi. 78 second instar P. buenoi. 83 third instar P. buenoi. 18 fourth instar Ai'ctocorixa alternata. 10 fifth instar Arctocorixa alternata. From this it is seen that to this date the two species have remained separate. These counts were made after the reared material had been studied and both species could be recognized readily. What happened in this pool after this date can not be determined, for no collections were made later than July 19. Life Cycle in the Laboratory. The development of this species in the various aquaria followed quite closely the changes taking place in nature, being, however, somewhat earlier. On April 20, a considerable number of nymphs were brought in from Bool's and placed in a large rectangular aquarium prepared for them. On April 28 two had molted to the next instar, and by May 15 they were all in the fifth instar and doing fine. Up to June 2 this aquarium was kept at a north window in an upstairs room, where no sunlight reached it. Since no adults appeared here, while they were doing so elsewhere, this was moved to a sunnier place outside, with the result that by June 4 many had tried to emerge, numbers dying in the attempt. Under labora- tory conditions, molting appears to be a precarious process. The first adults to appear during the spring from overwintering nymphs were a male and a female, which died emerging May 11. By May 15 several had made the transition successfully, and it was possible to determine the species presenting this peculiar wintering habit. It will be noted by field notes above that there were no adults in Bool's on May 21, so that those in the greenhouse were brought to maturity earlier than in nature. In another aquarium adults began to appear June 5, and were followed the next day by the majority of the others. The first eggs were noted June 13, and were numerous on the sides of the jar June 14, thus estab- lishing a maturation period of about eight days. A similar time is re- quired for incubation. 224 THE UNIVERSITY SCIENCE BULLETIN. In one large aquarium jar was placed ground cattail stems to the depth of one-half inch. The cattail had been soaking all winter in the pool and was readily reduced to a flocculent mass by passing it through a grinder. After drawing off the water two or three times, and replacing with fresh water, the jar was ready for use. Bugs of this species were placed herein and maintained themselves throughout the season without further attention. The overwintering nymphs became adult, mated, and laid their eggs, which hatched in due time. On July 6 all of the adults were dead and nymphs up to the sec- ond instar were noted feeding. The hot rays of the sun shining through the glass wall of the jar were not favorable to the bugs, though some survived, for by August 7 there were several nymphs in the fourth or fifth instars. August 21 three adults had arrived and the remaining nymphs were in fifth instar. These became adult sometime during the first week in September. The rearings were not followed closely from this time on, but the evidence on hand seems to show that these adults that emerge the last of August give rise to the nymphs that overwinter. Thus there are two generations a year, one overwintering as a nymph and becoming adult in June, the other coming on in July and emerging in late August. Some fifty pairs of new fledged adults of the first generation were placed in petrie dishes in an attempt to ascertain the number of eggs each female would lay. In every case the bugs died without laying a com- plete egg complement. Floating cages were placed in Beebe Lake in a like effort, but were disturbed, and after two or three attempts the project was abandoned. From the immense numbers of these bugs present in suitable waters, there is every indication that they are prolific and capable of foraging in close quaters. Since both nymphs and adults have been recovered from fish stomachs, they afford a possible source for the increase of a food supply by their artificial propagation. Of all the Corixids with which the writer is familiar this species presents some of the most likely possibilities in the regions where they may be found. The absence of functional wings in the majority of them and ability to forage in close quarters are factors quite in favor of their use in pools set apart for their artificial propagation. DESCRIPTION OF STAGES. The Egg. Size. Height, 0.546 to 0.572 mm.; diameter, 0.325 to 0.39 mm. The egg when first laid inclines to the minimum measurement, and when con- taining well-developed embryo attains the greater dimensions. Shape. Varies with development within, asymmetrically ovoid. An- terior end more slender and terminating in the usual micropylar tip. Greatest diameter about the middle of the egg. The shape of the freshly laid egg is more slender than that of the one ready to hatch. Color. Pearly white when first laid, darkening to yellow as embryo develops within. When ready to hatch the color is yellow, the base of the micropylar peg is black, and the claws of middle legs of the nymph within are visible as dark lines. The eyes are red, and the dorsal ab- dominal glands show through as faint pink blotches. hungerford: aquatic hemiptera. 225 The attachment disc of the egg is smaller than in some of the other species. Two eggs are figured on pi. XXVIII, fig. 15. These are drawn to same scale and show the difference in size and shape between the newly laid egg and the older egg. First Instar. Size. Length, 1.09 mm.; width of body, 0.65 mm.; width of head, 0.494 mm.; space between eyes, 0.299 mm. Shape. Flat, width of body greater than one-half the length. As time for first molt approaches the body becomes thicker in dorso-ventral line, a fact which holds for the other stages as well. Color. Eyes dark red, body mottled with smoky grayish-black. Pat- tern distinct, as shown in pi. XXVII, fig. 7. Pattern about as described for second instar, with the exception of mesothorax, where irregular blotches of dark pigment replace the transverse arcuate bands described below. Structural PeculiaHties. The limbs in this stage are proportionately larger than in following instars. The stout hairs fringing the limbs are not as definitely arranged for a given purpose as later. The fringe of swimming hairs on hind limbs made up of few hairs. The middle limbs, which in the adult are so slender and long, are thick and no longer than the hind limbs. The femur is as long as tibia and tarsus together, which are subequal. Tarsus is 1-segmented, and ends in two long slender claws, which nearly equal the length of tibia and tarsus together. Hind limbs not conspicuously flattened as in later forms, the swim- ming hairs few, perhaps a dozen in each row, and confined to the tarsal segment, which ends in a pair of almost spine-like claws. These claws are about half the length of tarsus, and straight, save for a slight devia- tion from a straight line at a point two-thirds the distance from their base. The dorso-caudal side of hind tibia with an irregular row of 10 to 12 short, stout spines. A few other less conspicuous spines upon this seg- ment and two longer ones on caudal margin of distal end of this seg- ment. Middle Leg. Two short spines on anterior margin of femur, and two long ones near distal end. Tibia sparsely covered with short, stout hairs, a long one on anterior margin near base, two near distal end. The marginal series of spines as delineated. Caudal Segment. Pair of short peg-like spines astride the median line. Caudo-lateral angle of body with five pairs of long spines, cephalad of which are two short ones. The penult segmental margin, 12 long spines cephalad of which are two or three short ones. The ante- penult segmental margin, a pair of subequal long spines and cephalad of these two or three shorter ones. Second Instar. Size. Length, 1.638 mm.; width of body, 0.858 mm.; width of head, 0.65 mm.; distance between eyes, 0.364 mm. 15 — Sci. Bui. — 1669 226 THE UNIVERSITY SCIENCE BULLETIN. Shape. A little more elongate than in first instar, the width now about half the body width. Color. Eyes very dark red, as are the dorsal abdominal glands. Cephalic aspect of head shows the cephalic end of the median dark longi- tudinal band, noted below. This band extends down upon the front to the level of the lower inner angles of the eyes. A dark spot lies lat- erad of the lower end of the median band, about three-fifths to two- thirds the distance to the inner angle of the eye. Dorsal aspect: head with median longitudinal smoky band visible from front to highest point of vertex. Between the caudal end of this line and the eyes lie two pairs of dark, more or less elongate, spots. The prothorax is marked on each side with two dark, roughly triangular spots of unequal size, their apices directed toward the margins. The smaller spots just laterad of median line and the larger ones laterad of these. The prothorax often marked by a transverse band on caudal margin. The mesothorax is marked by three pairs of very irregular and often indefinite, smoky blotches of unequal size. The abdomen is marked by reddish transverse bands that follow the abdominal sutures. These give way to triangular sooty blotches at the margins. The two large, dark dorsal glands have arcuate anterior margins and convex posterior margins. A dark circular spot marks the anal opening. The middle limbs have the joint between femur and tibia slightly smoky, and the tarsus is crossed by faint median band. The tibio-tarsal joint of hind leg is dark and a band crosses the middle of the tarsus. A dark spot on the hind tarsus is characteristic of all the nymphs of this species, and mark them Trom the nymphs of Arctocoi'ixa alternata taken at the same time. Structural Peeulianties. The hairs on limbs in more definite series. Swimming fringe of hind legs still confined to margins of tarsus for the most part, but composed of a larger series of more closely set hairs, some 40 in number. The claws of the hind tarsus are now one-third the length of this segment, and appear incised about midway of their length. The relative lengths of limb segments much as in the previous instar, but the entire limb more slender. The marginal series of spines as delineated in the figure. The pair of peg-like spines astride the median line on caudal margin in this and all other instars. A cluster of five long spines at caudo-lateral angle of last segment and about five short ones anteriorly. The penult segment of abdomen is margined by five spines, the second one from the caudal margin elongate. The ante- penult segment of abdomen is margined by about seven spines, the first, second and fourth longer than the others, the second one being twice as long as any of the rest Third Instar. Size. Length, 2.21 mm.; width of body, 1.04 mm.; width of head. 0.806 mm.; distance between eyes, 0.286 mm. Shape. Length now two and a fifth times the width. Color The face has the dark blotches between the lower inner angle of eye and the dark longitudinal median line of former instars. In dorsal view the head is marked either side of the longitudinal median HUNGERFORD: AQUATIC HEMIPTERA. 227 stripe by a spot of dark pigment. On the hind margin of the head there are two spots, visible only when the head is bent forward. The caudal margin of prothorax is margined with a dark band. Base of meso- thoracic wing-pads marked with dark irregular spot. Hind margin with arcuate band of color and two faint arcuate bands upoij the disc. The metathorax is marked with pairs of irregular smoky spots as de- lineated. Abdomen markings as in former instars. Structural Peculiarities. The wing-pads are now well marked and ex- tend back slightly more than half the length of the margin of the meso- and metathorax taken together. Tibia as well as tarsus of hind leg with swimming fringes. Claws of hind tarsus now not more than one-fifth the length of the tarsus. The claws present the peculiar incised ap- pearances as before. The middle femur is longer than the tarsus and tibia together. The marginal series of spines as delineated. Fourth Instar. Size. Length, 3.072 mm.; width of body, 1.43 mm.; width of head, 1.19 mm.; distance between eyes, 0.39 mm. Shape. About as in third instar. Color. The ground color is pale fuscous with darker markings ranging from smoky to reddish-brown. The face bears the pair of smoky rec- tangular blotches noted in former instars. From above the vertex is marked by three longitudinal stripes. The median one is slender and the lateral ones irregular in outline. The thorax is marked as delineated in the plate. The darker part reddish-brown, the scroll on the metathorax being the most characteristic. The abdomen is crossed by reddish-brown transverse bands, which at the margin of abdomen blend into triangular smoky spots. The body of abdomen is further marked by two longitudinal broken bands of fairly dark pigment, one either side of the dorsal glands. These converge from the base of the abdomen to the caudal end, where they meet. The caudal margin of hind tarsus bears a roughly triangular dark blotch, its apex reaching in some cases two-thirds of the distance to the cephalic margin. Structural Peculiarities. The wing-pads now extend more than two- thirds the length of the meso- and metathorax. The hind limbs are now well adapted for swimming, the hind tarsus being broad and flat, and the swimming fringe very complete. The claws are reduced now to perhaps one-seventh of the length of the tarsus, and are less conspicuous than formerly. There is a small tibial comb of six short spines at distal end of the tibia. This structure is present but inconspicuous in the previous instar. The marginal series of spines as delineated. Fifth Instar. Size. Length, 3.9 mm.; width of body, 1.7 mm.; width of head, 1.3 mm.; distance between eyes, 0.39 mm. Shape. As before, save that the length is greater in proportion to width. Color. Color pattern substantially as in previous instar. The long wing-pads, however, are darker. 228 THE UNIVERSITY SCIENCE BULLETIN. Structural Peculiarities. Wing-pads now long, reaching to the second abdominal segment. The hind tarsus is still 1-segmented, and claws re- duced. The tibial comb of hind tarsus is composed of longer spines than before. The neutrality of the caudal segments of the nymph, in contrast to those of the adults, is illustrated in the drawings on plate XXVTI, A study of specimens killed while emerging shows the marked transforma- tion that takes place between nymph and adult. The antennae of nymph are heavy blunt-tipped appendages, plainly 2-segmented, with a con- striction on the distal segment that may indicate that it is divided into two segments. See drawing on plate XXVII. Behavior of Adults There are some points in the economy of the lives of these insects worth noting. It is one of the very few water insects overwintering as a nymph. In fact, the only one known to the writer. For some time it was not clear as to why there should be this exception. It seems, however, that since the species seldom, if ever, flies, but lives in permanent waters, there is no occasion for the annual fall and spring migrations indulged in by other species. Most Corixids fly to larger pools to winter and in spring fly back to repopulate the shallower ones. The adults of this species are given to burying themselves in the floc- culent ooze on the bottom of the pool, and are thus difficult to locate. In common with other species, they come to the surface for air, and if in water of any depth are likely to head downward from the surface, swim- ming in a spiral to the bottom. In accounts dealing with the stridulation of the male Corixids it is stated they make their music at night. Some of these which were brought into the laboratory surprised us with their chirping one cloudy afternoon. Their stridulation was distinctly audible across the room and sounded somewhat like that of distant crickets, save that the chirps came forth in couplets. Sutnmary. The species here discussed winters as a fourth instar nymph, reaches the adult stage about the first of June, and after a matur- ation of eight days begins oviposition. This generation becomes adult during August and starts the generation that overwinters as nymphs. The species is capable of living in great numbers in a pool. The nymphs have been seen to strip the chlorophyll from filaments of Spi- rogyra and an examination of the stomachs of many of them shows that they consume quantities of living chlorophyll from the lower plant or- ganisms that make up the flora of the pool bed. This herbivorous ten- dency reduces the uncertainty of food getting and accounts in a measure for their success. It has further been demonstrated that they can complete their life cycle by foraging upon a flocculent mass of ground Typha and its attendant population. The facts above presented, when combined with the lack of functional wings, suggests the practicability of rearing them artificially. Since the nymphs of this species have been recovered from the stomachs of fishes, it may be that this form, easy to manipulate, can be utilized in increasing the food supply for young fish. hungerford: aquatic hemiptera. 229 Arctocorixa alternata Say. These are medium-sized Corixids, barred with light and dark brown, that are to be found in pools, ponds and quiet stretches of streams throughout the country. They present a perplexing range of variation in size and pattern and afford a most difficult problem in the fixation of the species. The writer published an account of the life-history of the form common in Kansas, and presents here some notes on the variety prevalent in the waters about Ithaca, N. Y.* Habitat. While this bug has a wide range of habitat, it is found perhaps more than any other in streams. About Ithaca it was often taken in Bool's Brook, while other species, taken in the upper spring-fed pool and in the fresh water at its outlet, were absent from the stream proper. • Hibernation. In common with many other Corixids this species is active in open water throughout the winter, the adults exhibiting con- siderable activity even in waters covered by a layer of ice. Mating. The first mating noted in nature took place April 17, in a pool by a railroad trestle. The water of this pool was still very cold. Pairing takes place in the water, and lasts for various lengths of time, often an hour or more, during which time the female continues to feed. The male mounts the female and clasps her vdth his forelegs while the tip of the abdomen is passed around the left side. The pegs on the male palse make the embrace more secure, while the peculiar structure called the strigil, upon the right side of the abdomen, vdthout doubt serves a similar purpose. This latter was considered by Handlisch as an instrument for stridulation, but this is denied by other workers. Although mating may take place any time during the day, it has most frequently been observed toward evening. Oviposition. The first eggs were taken April 19. There were 59 of them laid upon the sides of the aquarium during the night by five females. This is a little earlier than they were found in nature. In nature the eggs are attached singly to any available support in the water. They have been found on the stems and leaves of various water plants, upon sticks and boards, upon the stones, and even on the shells of living snails. Incubation. The duration of incubation of the eggs depends some- what upon the temperature of the water. Those laid earliest in the spring began hatching May 2, after a period of two weeks. In warmer weather the time may be reduced by half. Hatching. The process of hatching with the Corixids is diff'erent from that observed in the case of other water bugs. The egg shell breaks about the base of the micropylar peg and then splits into six or seven sections, each one of which curls outward and downward as the opening is enlarged. The writer has often had the eggs under observation at time of hatching. First the top of the egg bulges slightly, then there is a sudden giving away and the nipple-like tip of the egg pops loose * Although this was identified for me as the same as the Kunsns form. I :im satisfied from careful study that the varieties are distinct species. 230 THE UNIVERSITY SCIENCE BULLETIN. at its base and the loose ends peel back, one of them bearing the at- tached micropyle. The process is now best viewed from the side. First a clear bubble appears, bound by a delicate transparent membrane. This grows until it reaches a height about one-fifth that of the egg, and stops. Then gradually the head of the nymph comes up and fills the bubble. (See pi. XXVIII, fig. 12.) The process so far may have consumed some three or more minutes, but the nymph is not yet free. Another heave, the membrane that enclosed the bubble splits and a moment later the nymph, plastic and soft like a worm, swells the exposed part of the body repeatedly until it is all but free. Then it may lie exhausted a few moments, or even minutes, before a final kick sets it at liberty. As soon as it is liberated it is capable of swimming rapidly for several centimeters, and then appears exhausted. It begins feeding before the color pattern is complete. The hatching process takes place under the water, and the behavior of the new-fledged nymph in relation to an air supply is noted below. The time required for emergence from the egg ranges from four or five minutes to a half hour. One egg began hatching at 3.51 p.m. The parts of the shell peeled back in six divisions. Midway between the eyes at the apex of the hatching nymph there was an organ that pul- sated vigorously at times. At 4:15 the upper edges of the red eyes began to show and the part before the eyes was larger than the re- mainder of the head. One-half of the eyes was exposed at 4:25. Body completely out at 4:.31. The limbs of the nymph, incased in the shell, are stretched caudad upon the venter, and the margins of the body are rolled ventrad. The ventral side of the nymph is on the bulging side of the egg, and there is a deep transverse fold on the dorsum, so that the back of the head and dorsal abdominal glands are approximate. Figures of the hatching nymph are shown on pi. XXVIII, fig. 12. The remains of this thin embr^ onic sheath lie about the opening of the abandoned egg like a cast-off garment. (See fig. 12.) Behavior of Newly Hatched Nymphs. The nymph just freed from the egg shell presents little pigmentation. The limbs and the flat margin of the entii-e body are as transparent as glass. The head and central part of the body is pale yellow. The eyes are red and the two dorsal abdominal glands are a pale red. There are two faintly pale pink in- definite regions laterad of the middle line on the thorax. This transparency makes it possible to study the question of respira- tion, for as soon as the tracheje fill with air they become silvery. There is still a large problem to solve relative to the reception of the first air supply. Tillyard's work with the dragon-fiy nymphs suggests an inter- esting field of study with Corixid nymphs. A few observations were at- tempted in a preliminary way. Eggs ready to hatch were placed in a slide cell, the chamber filled with water and covered over with a glass cover slip. The only air then available to the nymph would be such as is found dissolved in water. By the time the nymph was a half hour old, however, there usually collected a bubble of gas somewhere under the slip. In those nymphs observed the tracheae remained undefined until the little bug made contact with one of these bubbles, whereupon they im- hungerford: aquatic hemiptera. 231 mediately became silvery. From the behavior of young Corixids, it would seem that respiration must take place through the skin for they seldom come to the surface, yet in the few experiments tried it was not demon- strated that air was taken up in that manner. The nymphs were able to survive for many hours in cloth covered jelly glasses submerged in water. Number of instars. There are five nymphal instars, which are shown on plate XXVI. Maturity. This could not be determined from the overwintering adults and was overlooked in the summer. The laboratory notes were obtained from a start of nine individuals that were placed in a large circular aquarium April 3. Seven of these were females. By the last of the month there were but three individuals remaining, and May 9 only two were left, but first instar nymphs had appeared. Some of these changed to second instar nymphs May 12, and reached the fourth instar June 2. The two overwintering adults were still alive and laying eggs. June 10 found all stages from first instar to the fifth present. June 14 the first one of the spring generation reached the adult stage, followed by another on the 19th. There were still first instar forms present. In fact, eggs and newly hatched were present up to July 18. Since the overwintering adults were not removed, it is impossible to say whether the young represent a second generation or merely a continuation of the first. The hot weather of the last week in July brought the rearing to a close, and was valuable only in giving all the nymphal instars for study and establishing the approximate time for the emergence of the spring brood. It is certain that the adults of one year may live to see adults of the next. Parasitism. In Bool's Backwater, where this Corixid was found throughout the spring in company with the nymphs of Pahnacorixa buenoi, the infestation of Hydrachnids was heavy. On May 9 a large catch of this species showed 85 per cent of the bugs infested with one or more mites, some of them with a dozen. May 15 there was not an adult to be found that did not bear mites. On June 8 the mites freed them- selves from their hosts in the laboratory, and on examination of the in- sects in the pond June 11 found the boatmen much less burdened than before and almost entirely free June 13. June 18 not a single "mited" Corixid was noted. DESCRIPTION OF STAGES. The following brief description of size and color is given for com- parison with P. buenoi of same pond. The structural comparative studies of nymphs of various species are reserved for a future paper. The Egg. Size. Diameter, 0.369 mm.; height, 0.372 mm. Shape. Variable, depending on development of embryo within. In general ovoid, but with the usual greater convexity of one side. Color. Pearly white when first laid, darkening to yellow. There is a hexagonal reticulation plain to see under high power and proper lighting. 232 THE UNIVERSITY SCIENCE BULLETIN. First Ins tar. Size. Length, 1.29 mm.; width af body, 0.754 mm.; width of head, 0.598 mm.; distance between eyes, 0.416 mm. Shape. Width greater than one-half the length. Body very flat in the newly hatched. Color. Newly hatched almost transparent, but in the course of a few hours assuming the color pattern delineated in fig. 8 of pi. XXVI. Gen- eral color is pale yellow, the darker pigment being smoky. The pro- thorax, mesothorax and metathorax each bear a pair of irregular smoky blotches. The pair on the metathorax being large and extending to lateral margins of the seg-ment. Part of the color of the abdomen is due to the food in the digestive tract vnthin. In the nymphs about ready to transform the entire body is darker. Second Instar. Size. Length of body, 1.77 mm.; width of body, 0,936 mm.; width of head, 0.78 mm.; distance between eyes, 0.442 mm. Color. Darker than in other instar. The body transversely banded with darker pigment. The transverse lines on thorax and abdomen are reddish-brown. The other dark areas smoky. A smoky band parallel with margin distinguishes this species from the same stage of Palma- corixa biienoi. The head is marked by three longitudinal smoky bands. Third Instar. Size. Length, 2.31 mm.; width of body, 1.19 mm.; width of head, 0.99 mm.; distance between eyes, 0.52 mm. Color. Third instar nymphs often darker than second and have a definite color pattern. The hair upon the wing-pads now appears, and enmesh the air. Head: eyes dark red, head pale, marked by a median longitudinal dark band; faint lines lie between this and the eye, one on either side. Rear margin of head fringed with black hairs especially near the dorsal median line. Margin of wing-pads dark and fringed with a pile of fine dark hair. Prothorax hidden. Mesothorax is traversed by a reddish-brown band near posterior margin. The hairy fringe of fore wing-pads continues across the dorsum. Metathorax pale with a smoky pattern of five spots, the median one crossed by the pale median streak that reaches the length of the thorax. These spots consist of crescentic patches in front, their inner horns almost touching the median triangular patch of color, on either side of which lie the right angled patches. Posterior margin reddish-brown. Abdomen; margin smoky gray, the suture between the tergites marked by dark reddish-brown bands; two rows of irregular quadrangular patches of smoky color lie on either side of median line, from third to sixth, inclusive. Three pairs of odoriferous pores, front ones on caudal margin of third segment small, the second and third pairs larger, and the very dark glands are apparent beneath the integument. Dark ring around auiiSr Legs for the most part pale; hair fringe dark. hungerford: aquatic hemiptera. 233 Fourth Instar. Size. Length of body, 2.86 mm.; width of body, 1.38 mm.; width of head, 1.2 mm.; distance between eyes, 0.494 mm. Color. Pattern distinct. Head with median dark longitudinal band. Wing-pads dark, covered with dai-k pile. Caudal margin of meso- thorax smoky. Metathorax with an arcuate band of reddish-brown inter- rupted on the median line. Two other pairs of smoky spots are upon the disc of the metathorax. A pair of small triangular spots separated by a narrow median line of pale and a larger pair of indefinite quadrangular smoky blotches laterad of these. The intersegmental lines of abdomen reddish-brown, very distinct. The large dark abdominal scent glands open by paired pores on caudal margin of the fourth and fifth seg- ments. The abdomen is marked by a smoky submarginal band and each segment bears two pairs of rectangular smoky gray spots, the outer ones forming distinct longitudinal rows. Structural Peculiarities. Wing-pads reach to the posterior margin of the metathorax, as in other Corixids. Fifth Instar. Size. Length of body, 4.21 mm.; width of body, 1.61 mm.; width of head, '1.46 mm. ; distance between eyes, 0.624 mm. Color. Pattern as in fourth instar, only more striking and darker. The two pairs of spots on disc of metathorax united to form a transverse arcuate band. Posterior margin of metathorax with broad reddish-brown band. Structural Peculiarities. Antennae 2-segmented. Wing-pads extended past the posterior margin of thorax, as in other Corixids of the same instar. Summary. Arctocori.va alteynata has the widest range of waters of any of the boatmen studied. It has been the only one commonly taken in flowing streams. The species winters as an adult and begins mating in the region of Ithaca, N. Y., about the middle of April, while the waters are still very cold. Copulation takes place under water and lasts some- times for hours. Oviposition begins shortly and continues until some of the young become adult, if not longer than this. The eggs hatch in from one to two weeks, depending on the temperature, and the instars require about one week for each stage. The last stage occupying a few days longer. The first generation emerges about the middle of June. Food of Corixids. INTRODUCTION. In a paper which appeared in the Journal of the New York Entomological Society, 1917, the writer called attention to the fact that the water boatmen gather their food supply from the ooze at the bottom of the pool. This flocculent material they sweep into their mouths by means of the flat rakes of their fore legs. In view of the discrepancy that exists between textbooks and the writer's notes on the subject, he deems it worth while to present under this chapter heading some of his data relating to the question, even at the expense of the general balance of the work. Therefore, material that would otherwise be presented in a single paragraph is given a larger treatment under the following outline : OUTLINE OF STUDY ON FOOD OF CORIXIDS. Historical sketch. General habits of Corixids. Structural adaptations. External. Internal. Studies relating to the food of Corixids. Object. General plan of experiments. Pure cultures and surveyed cultures to determine essential forage and selected forage. History of cultures. Survey of culture. Analysis of stomach contents. Technique. Special studies. (Selected as typical.) HISTORICAL SKETCH. De Geer, 1778, says that Corixids are carnivorous, arid Latreille, 1802, says, also, "Leurs habitudes sont carnassieres." Since that time all textbooks and treatises relating to the general habits of water bugs either state that they are preda- tory or are silent regarding their feeding habits. In a care- ful review of the literature the writer has been unable to find a suggestion on the part of any one to the effect that the (234) HUNGERFORD: AQUATIC HEMIPTERA. 235 water boatmen have any herbivorous habits. He believes, how- ever, that the posthumous paper of H. Rathke, 1861, sent in by his pupil H. Hagen, and dealing with notes on Hydrometra lacustris and Naucoris cimicoides, treats really of a Corixid and not an Naucorid. In spite of the fact that Kirkaldy, who must have had a good knowledge of German, for he wrote one large paper in that language, quotes from these "Studien Zur Entwicklungsgeschichte der Insekten" in his account of the life history of a Naucorid, the writer cannot accept the account as dealing with a Naucorid at all. The description of the eggs certainly applies to Corixid eggs, not to any Naucorid eggs the writer has ever seen described. Let the reader ex- amine the drawings of the eggs of the Corixids on plate XXV, and then read carefully the following : "Eier eines Insektes (Naucoris cimicoides). Es waren dieselben einzeln, doch mit unter in ziemlich grosser Zahl in der Nahe von e".nander an die untere Seite der Blatter von Polygonum amphibium angeheftet. Sie hatten eine Lange von Vz'" und beinahe die Form einer Citrone nur waren sie ein klein w^enig langer und gingen an dem einenende in einen sekr kurzen, aber auch sehr dicken Stiel iiber, auf dem sie angehftet waren, so dass sie mit der achse auf dem Blatte senkrecht standen Die Eischale war bedeutend dick, entweder rein weiss oder weiss mit einer Beimschlung von Lehmforbe, fast ganz undurchsichtig, starr und hart, so dass ich in ihr Kalk vermuthete. . . ." The eggs were lemon shaped. They were perpendicular to the support. The description fits the egg of some Corixids, but not of Naucorids. The notes go on to state that the eyes turned carmine red, that the head of the embryo lies always on the free end and comes out first, etc. Having concluded that Rathke must have been watching a young Corixid, the following note is indeed of interest here : "Die Jungen schwammen sehr schnell, waren uberhaupt sehr beweg- lich und frassen, obgleich sie einen kurzen Riissel hatten, zerbrockelte und zergangene Conferven und Pristleysche Materian, wodurch ihr gan- zer Dormkanal unrein griine Farbung erhielt." The larvae ate the Conferva until the intestine was green ! Now it may be that Nancorids do the same, though the writer is taking the liberty to transfer this note to the place where he thinks it belongs, and to credit to this scientist the first and only note on the herbivorous tendency of a water bug. As be- fore stated, all the others have classed Corixids as carnivorous. Thomas, 1871, gives the account of Corixa ovivara West., 236 THE UNIVERSITY SCIENCE BULLETIN. which lives in the rivers of Canara and which he says eats fish eggs, from which fact Westwood derived its name. The ob- servation follows: "I observed it myself in a still hollow in a rock, where the water was quite clear and only two or three inches deep. The insects kept tossing the ova up from the bottom and following them closely up to the surface whence they gradually subsided to the bottom of their own weight, the insects apparently adhering to eggs all the time, but the moment they were at the bottom they vigorously were tossed up again. I daresay it attacks other spawn also, but the ova I saw it engaged with were those of the Masheer barbas mosal, commonly called 'Masheer,' the most valu- able fish in the Indian rivers." Mr. Thomas sent an extract from the report of Pisciculture in S. Canara "detailing experiments made by an intelligent ob- server to test the destructive habits of this insect. In one instance a hollow was watched in which were many freshly deposited ova but no Corixse. The next morning the latter were there in large numbers, and nothing left but the empty egg shells. In another experiment the ova were placed in a finely woven basket and the Corixse immediately came in quantities and endeavored to penetrate from the outside." White, 1873, made careful studies of the behavior of Cor- ixids, and described their feeding movements but stated, "I have not been able to make out satisfactorily of what the food of these insects consists. (Westwood has recently described an Indian species which is said to feed on eggs of fish.) Evidently White doubts the occurrence of the observation. They often rest on a stone and seem to scrape its surface with the palse which they bring rapidly and alter- nately to the mouth. In the same manner they scrape a root of Lemnae passing it rapidly between the palae. On examining a stone from which a Corixa had apparently been obtaining food, a small alga and a few Rctifera and other animalcules were seen." Kirkaldy, 1905, came, through his observations of their be- havior, to state, "Dufour says they are carnasial. I think that small worms, Rotifera, etc., form a large part of their food. Kulgatz, 1911, in "Die aqatilen Rhynchoten Westpreussens" describes the front legs of Corixa as "Organe zum Packen und F'restholten der auszusaugenden Beute" and Brocher, 1913, says fore legs are for prehension "Si un petit animal, larve ou elles I'attrapent et le maintiennent applique contre leur bouche . . ." The writer has given at some length the observations of others. He has observed Corixids catch prey, but finds that hungerford: aquatic hemiptera. 237 the observations do not represent the usual feeding behavior, which is given elsewhere. GENERAL HABITS OF CORIXIDS. Buchanan White, 1873, gives us perhaps the best general account of the behavior of the Corixids. Johannes Hagemann, 1910, published an extended dissertation on the anatomy and behavior of these insects. White pictures them so well that his words are here re- peated : "The adult Corixa in swimming uses only the posterior legs. These legs are also used for cleaning the elytra. In doing this the animal uses one or both legs, brushing the pronotum, elytra, the underside of the hind body, and the long hairs at its end. To assist perhaps in this cleaning process, the inside of the hind tibia and the base of the first joint of the hind tarsus are provided with what may be called the comb or rake hairs. These are shorter and stiffer than the swimming hairs, and are widened and flattened at the extremity, being in fact somewhat oar-shaped, and truncate at the apex, which has five long teeth. These teeth are admirably adapted to rake out any particles of foreign matter which may have lodged in the fine rostrations with which the pronotum and elytra of many species are sculptured. The species which have no rostrations (such as Macrocorixa) are, equally with the rostrate species, provided with rake hairs. These rake hairs are not present in the young. The middle legs are used for standing on, the long claws clasping stones or plants, and the body of the animal remaining at some distance from the object rested on. The animal can also walk in a kind of way with these legs, its progress being at the same time assisted by short, jerking strokes of the hind legs through the water. When at rest and not clasping anything with the claws, the animal rises to the surface of the water. The front legs or palae are used for feeding. When in action they are brought rapidly and alternately to the rostrum. In action they hang downward, their tips approaching each other; in swimming they lie backward along the sternum." A glance at the photograph of the living bugs under water shown on plate III will indicate their characteristic poise. The boatmen spend most of their time in the shallow waters, where they rest upon the bottom, their mottlings of yellow and brown rendering them inconspicuous midst the flocculent bottom ooze. It might here be mentioned that the May fly nymph, living in the same situation, is similarly camouflaged. Now and then the boatmen swim quickly to the surface, ex- pose the thorax for a brief moment, and dart below again. In turbid waters the presence of the boatmen is determined only by the brief flashing of their bodies as they take air at the surface. 238 THE UNIVERSITY SCIENCE BULLETIN. STRUCTURAL ADAPTATIONS TO FEEDING. External. The Corixids possess the most obvious adaptations of their limbs to definite functions of any of the v^ater bugs. As early as 1833 Leon Dufour, in his "Recherches anatomiques et Physiologiques sur Les Hemipteres accompagnees de consid- erations relatives a I'histoire naturelle et a la classification de ces insectes," gave a detailed description of the various limbs of Corixids. In 1873 Buchanan White, to v^^hom we owe a great deal for a splendid series of notes regarding Corixids, mentioned the function of the different parts, based upon his personl observation. He states that the hind limbs are flattened and fringed for swimming, that the long, slender middle limbs anchor the bug to some submerged object, and the fore limbs are employed in food getting, though he con- fessed his uncertainty as to the forage gathered. Comstock, in his "Introduction to the Study of Entomology," also notes the differentiation of the limbs. The very unique mouth parts that led Borner, 1904, to place them in a suborder by themselves, and for which he proposed the name Sandalioi^^liyncJia, are well adapted to the unusual method of feeding practiced by these insects. There is no extended beak as in other bugs, yet a morpho- logical study of the various parts, such as those made by Metschniikoff, 1866, Giese, 1883, Wedde, 1885, Heymons, 1899, Bugnion and Popoff, Muir and Kershaw, and others indicate the close relationship of these with other bugs. The draw- ings on plate XXX show the mouth parts. The face of the bug is seen to be flat with the buccal opening on the front side rather than at the tip. Two triangular flaps, controlled by muscles, permit the enlargement of the orifice. The sty- lets are very short and stout, the outer pair blunt-tipped and notched on their outer margins. A condition quite different from the pointed and retrorsely-barbed stylets of Notonecta, for instance. The inner pair are broad, placed one above the other, and rolled into semi-cylinders. Bugnion and Popoff say of these internal stylets of Hemiptera: ". . . The internal stylets forming by their juxtaposition two conduits, very fine, one of which ordinarily placed on the dorsal side is the "Canal de succion" which is continuous from beak to HUNGERFORD: AQUATIC HEMIPTERA. 239 phamyx, while the other, situated on the ventral side, is the "canal of execution" (outlet of salivary glands.) With the Corixids the intake canal is relatively large, al- lowing the ingress of large solid particles. Internal. The oesophagus, as shown on plate XXX, is slender as in other Hemiptera, but the mid-gut is large, accommodating a considerable quantity of food. The length is not strikingly greater than that of other bugs, such as Notonecta. The slender oesophagus enlarges to form the oesophageal valve, and the tract greatly enlarges to form a series of pouches. It then narrows slightly to form a more even cylinder. At about the level of the fifth abdominal segment it turns to the right and folds forward to near the front margin of third abdominal segment, where it makes a dorsal turn and bends caudad in nearly a straight line to the anus. The mid-gut ter- minates shortly before the last bend, as indicated by the at- tachment at this point of the four Malpighian tubules. An elastic walled rectal pouch is present, on the dorsal wall of which terminates the Malpighian tubules. STUDIES RELATING TO THE FOOD OF CORIXIDS. Object mid General Plan. Having determined the source of the food supply of the boatmen, there yet remained the question of the exact nature of their forage. The results herein presented have been gath- ered from experiments to determine the usual and essential diet of these peculiar bugs. A solution of this problem has been attempted by feeding the insects upon surveyed mixed cultures and upon pure cultures. The former to indicate the existence of selection in their foraging, and the latter to deter- mine if possible the essential organisms of their diet. Thus the body of this paper consists of a report of the (a) history and diagnosis of the culture, {h) its survey, and (c) an analysis of stomach contents of Corixids after living within the cultures. Technique. In order to use due care in the manipulation of the ma- terials the following precautions are observed: A given lot of boatmen of some species is selected and placed in clear water for a time, to remove from their bodies any foreign 240 THE UNIVERSITY SCIENCE BULLETIN. matter. Now, these bugs, we will assume, have just been taken in nature. Their digestive tracts probably contain food ma- terial. A few are examined to determine this point. These are two factors at this beginning point to be considered. If the bugs have been feeding recently, the material in the diges- tive tract might be confused with food taken in from the food culture. Therefore the bugs must be divided into two lots. One placed in a sample of the given culture at once to serve as a check on normal (not starved) feeding, and the results observed. The other lot is then allowed to remain in the clear water for a time sufficient to clear much of the digestive tract. For this purpose fresh glass aquaria, with a few peb- bles placed on the bottom to which the bugs may cling, serve admirably. This lot, then, may be placed in another jar of the culture and allowed to remain for times varying from thirty minutes, for food selection, to weeks, for determining maintenance ability of the culture. In making the examina- tion the bugs are removed from the culture to distilled water for a few minutes. Petrie dishes do very well for this, be- cause they are shallow. By means of the forceps a bug is caught by one of its swimming legs and placed in a drop of water on a slide. After removing its head one dissecting needle is run through the thorax to hold it in position on its venter, and the other needle dissects out the digestive tract entire. The carcass of the bug is then removed, fresh, normal salt solution passed over the digestive tract, and notes made as to the general position of the contents, whether in some part of the stomach or in the intestine. Usually there will be two masses of material. The dissecting needle pricks the stomach wall to liberate the material, which promptly speads upon the slide. The other mass is removed in the same way, then the cover slip is added and both of these smears studied under compound. Since the food is likely to be deep green in color, due to the plant chlorophyll, or at least to contain unicellular plant cells, or even bits of Spirogyra or Zygnema still containing plastids, it is convincing to make permanent mounts. To do this the smear is fixed in 8 per cent formalin to which has been added enough copper acetate crystal to give it a pale greenish tinge. This preserves the green color. The mount is then made in glycerine jelly in the usual way and sealed with asphaltum. Mounts made in this way can be used hungerford: aquatic hemiptera. 241 in demonstration for a long time. For detailed studies of di- gestion the usual histological methods must be followed. SPECIAL STUDIES. Carmine Feeding. As stated under the heading of general habits, the use of the flat palse of the fore legs in feeding is easily observed. It occurred to the writer that if powdered carmine were sprinkled over the sediment on the bottom of the aquarium it might be taken up by the boatmen in their feeding and serve as an index to the time it takes for food to pass through the digestive tract. If found in the stomach in large quantities it would add further evidence to the belief that they scoop the food into the mouth in quantities. Several experiments and demonstrations have been made by placing the powdered carmine upon the sediment in the bottom of the jars and then turning in Corixids to feed. If hungrj^ the boatmen will begin at once, and a dis- section of one of them after ten or fifteen minutes feeding will prove that they take up the carmine and organic ooze in quantities. The digestive tracts have been found packed from end to end with the red material. On plate XXX is given a figure in color of the digestive tract of a Corixid after feeding upon carmine covered forage. Permanent mounts of digestive systems in balsam make useful slides foi demonstrat- ing this point, since the walls of the stomach become clear and the red material within gives striking preparations. This carmine-feeding experiment was attacked from every angle in order to avoid drawing any false conclusions, A care- ful reading of the notes obtained will indicate how easily one could fall into errors by superficial examinations. The experi- ment was planned and executed by the following outline : Typha Culture 17129. A. Survey of culture. B. Stender with culture and carmine. a. Survey culture after 24 hours. b. Place Corixids here that have been in clear water for 24 hours. 1. Forage 1 minute and examine. 2. Forage 5 minutes and examine. 3. Forage 20 minutes and examine. 4. Forage 20 minutes, remove to clear water for 30 minutes and examine. 5. Forage 20 minutes, remove to clear water for 130 minutes and examine. 16 — Sci. Bui. — 1669 242 THE UNIVERSITY SCIENCE BULLETIN. ' C. Check. a. Boil some of the surveyed culture to kill organisms. 1. Place carmine over this in stender and repeat the series under Bb. Culture 17129 was made by grinding M^ater-soaked leaves -of dead Typha. These grindings had reached a state of balance before using in this experiment. It had been used to rear Corixids and so v^as knov^n to contain the essential elements of the boatman food supply. A survey of the culture is given elsewhere, but it is well to recall that it consisted of ground- up bits of Typha tissue, a few Englenids, some Tetraspora, some algal filaments, live and dead rotifers, about equally divided, some nematode worms, and here and there various protozoans. Some carmine was then sprinkled over a layer of this ma- terial in a stender and allowed to stand for 24 hours to note the effect of the carmine upon the animal organisms. The animals were alive and the nematodes and rotifers and some of the pro- tozoa contained carmine, not in considerable quantities, how- ever. One dead Oligochseta was quite strongly stained. Adult Corixids of the species Palmacorixa buenoi, after 12 hours in clear water, were placed on this carmine forage, and began feeding at once. By the end of ten minutes the anterior end of the stomach of one af them was carmine red. Besides carmine grains, there were present some rotifer skins, one with red in it, open jaws of rotifers, and some green Englenids. Other specimens show the presence of considerable carmine mixed with plant matter some algae filaments, and here and there a nematode. In all, the digestive tracts were filled with red matter, a little of which could be traced directly to the animals consumed. The colored drawing of a nematode shows one source of the carmine. To determine whether Corixids were after live animals or would eat dead ones, too, some of the Typha was cooked. An examination showed dead rotifers and worms, etc. Added car- mine to this, with the idea that the animals being dead could not ingest it. Corixids began foraging at once. An examina- tion of their stomachs showed that they were taking up plant matter and carmine grains, also some of the dead rotifers, etc. After a few hours the dead animals had taken up the stain and in this way would account for some of the red in the Corixids, hungerford: aquatic hemiptera. 243 for they continued to sweep in dead rotifers and protozoa along with green plant cells. Spirogyra Culture. It has been stated elsewhere in this paper that Corixids are very largely herbivorous; that the digestive tracts have been found to contain much chlorophyll. But the finding of pebbles in the stomachs of fishes is not taken as conclusive evidence that pebbles form their food supply. So with the boatmen. The writer felt that chlorophyll might be eaten by herbivores and these herbivores by Corixids, and the digestive tracts of the boatmen would be green. Moreover, even the carmine experiment cited above might be subject to criticism by those who had not made direct observations. Such skeptics might say that the carmine could be ingested by worms, amoebae, etc., and thus, through the eating of these organisms by Corixids, get into the stomachs. The contention that Corixids are largely herbivorous, is obvious to BiXiy who repeat these ex- periments for themselves, but to the writer's mind, nothing seals the incontestibility of the facts like the following dem- onstration. This demonstration has been repeated a number of times with three or four species of Corixids. Here are the notes on the first experiment : Washed a species of Spirogyra repeatedly in tap water until every organism perceptible under the low-power compound was removed, then placed a few filaments of this in a small Petrie dish and added an adult Palmacorixa huenoi. It began feeding at once and worked contentedly. It gathered up the green filaments, singly or by the half dozen, and slowly worked them backwards, using its palse like hands, to manipulate the algal threads which it pressed to its mouth. So intent was this bug upon the business in hand, that it was content to lie upon its back and eat, so every detail visible with a high-power binocular was seen. For thirty minutes this bug fed most in- dustriously. The spiral filament, moved from front to rear by the hand-over-hand movement of the fore I'mbs, was pressed to the face, the cell punctured and the green matter with- drawn. See plate XXX. Thus the threads of Spirogyra that were passed between the mouth and the palse of the bug were transformed from threads bright with green spirals to empty and transparent filaments. After a half hour's feeding, the bug 244 THE UNIVERSITY SCIENCE BULLETIN. was killed and the stomach seen to be packed with green chlorophyll. The contents of this stomach were fixed in 8 per cent formaldehyde plus copper acetate, and mounted in glyc- erine jelly, together with mounts of the Spirogyra before and after being foraged over by the bug. Drawings of these prep- arations are shown on plate XXX. The next day the ex- periment was repeated with two first instar nymphs of the same species. They, too, proceeded to feed at once as the adult had done. Culture 16217. (Ground Elodea.) History and Diagnosis. Ground-up tips of E'odea and chano'ed water repeatedly to wash out the free green chlorophyll matter. Studies of the grindings show Elodea, bits of tissue and single cells. Scenedesmus, threads of Gonatozygon and Oscellatoria, diatoms, large and small, a few heterotrichs, etc. Corixids added. Every examination made of the stomach contents of the bugs after foraging here showed the tract packed with green ma- terial. This consisted of cells of Elodea, filaments of Oscellatoria and Gonatozygon, desmids and the like. One A. alternata contained a thread of Gonatozygon 1 mm. long. Splendid demonstrations, all of them, of the plant feeding tendencies of these bugs. Culture 17129. A. (Ground Cattail.) History and Diagnosis. Gathered some dead cattail leaves from the marsh by the Field Station. Soaked them in water for a few days and then ground them up by means of a meat grinder. The i-esult was a flocculent brown mass of fine matter. This material was ground up on May 9 and the water changed frequently until the 11th, when Corixids, adult and nymphs, were added. They began foraging promptly. Ten days later they were still doing nicely. Examination of the forage showed much finely divided tissue, some Algae, mostly unicellular, such as Tetraspora and Englenae. The rotifers, dead and alive, make up the bulk of the animals. There are plenty of the cellulose tissue of the cat- tail, bits no larger than the Algae. Corixids Added. The examination of the stomachs of the bugs always showed them filled with brownish material, superficially like the forage. A close examination, however, indicated the absence of Typha tissue, and the abundance of the ramate jaw parts of rotifers. Much brown matter that could not be analyzed, and mixed with it the green cells of the Tetraspora, Englenae and some filamentous Algse. Even the large Arcto- corixa intcrrupta avoided taking in the Typha tissue, although it ate bits of Algas of larger dimension. The ground Typha serves as a stock for the growth of organisms eaten by the boatmen. Culture 17129 B. (Ground Cattail, sterile.) History and Diagnosis. Same as in 17129A. Boiled this repeatedly to sterilize it. Did not use the sterilizer, however, so the ground Typha soon spoiled even if boiled. " hungerford: aquatic hemiptera. 245 Corixids Added The first two Corixids added refused to eat the stuff, although when placed in 17129A they began feeding promptly enough. After the material was cold and had been repeatedly washed, the bugs foraged upon it. The stomachs contained very finely divided brown matter with no animal remains. In this culture no rotifiers and the like had had any chance to develop. The brown grindings, only the finest of them, were swept in directly. Culture 16220 (Alfalfa base culture.) History and Diagnosis Doctor Embody had a large circular aquarium in which he had placed ground alfalfa and a little manure. The culture had reduced itself to a spongy mass in the bottom and the water was fairly clear, with duckmeat growing on top. The plant life is largely Oscillatoria, diatoms, etc. present also. Corixids Added. Bugs were kept here for more than a month, and did very well. Their stomachs were always full of dark green material, which often consisted of great skeins of Oscillatoria filaments and little else. In some of them this blue-gi'een could be traced from fresh material in the fore part of stomach to broken up, disorganized particles in rectal pouch. Culture C. (Bran.) History and Diagnosis. Ground-up bran. Added Corixids. This experiment was not a success at all. Fer- mentation made life untenable for the bugs. Culture 16221. (Euglenas.) History and Diagnosis. A large rectangular aquarium. The bottom contained sand and the aquarium had been in use a long time. A green growth covered the sides and bottom. The water itself was green, due to millions of Euglenids! Corixids Added. A great many Corixids were placed here and after- wards examined. Their stomachs were packed green with Euglenids and little else! . Culture 179. (Largely Mougeotia.) History and Diagnosis. A large aquarium jar had been sitting be- neath a constantly running tap. It contained quantities of oozy material, having a brownish tinge. This consisted of diatoms, Scenedesmus, Gleo- capsa and Mougeotia filaments. The last the dominant organism. Corixids Added. Examination of Corixids after feeding here proved that they were consistently gathering the Mougeotia after their stomachs were packed with it. Culture 17143. (Mougeotia.) History and Diagnosis. Placed sand in the bottom of a large rec- tangular glass jar. Added some green material from a jar in Doctor Embody's office, Corixids Added. After a couple of weeks added a number of fifth- instar nymphs of P. buenoi and some adult A. altemata. After a couple of days examined the stomach contents of the bugs. In every case the 246 THE UNIVERSITY SCIENCE BULLETIN. tract was packed with pale green matter like the culture! This proved to consist almost exclusively of the clear filaments of Mougeotia, the contents of the cells of which were in a state of disintegration. The free granular green matter was obviously derived from contents of the Mougeotia cells. No animal organisms or their remains found in these examinations. Culture 16126. (Rivularia.) History and Diagnosis. A porcelain-lined, granite-ware pan, which had been used for some time as a watering vessel for the birds and chickens, contained a layer of brownish material over the bottom and up the sides. Upon examination the material was found to consist of debris and Rivularia natavs, no animals present. Corixids Added. Eggs of an undetermined Corixid were added and reared to second instar, when all died. The experiment was repeated with similar results. The water was not changed as frequently as might have been desired. Adults of R. acuminata and .4. altemata failed to live more than a few days in this culture. Culture 1754. (Slime Diatoms.) History and Diagnosis. The rocks of upper Fall Creek were covered with long, brown strings of gelatin in March. This was found to con- sist of great quantities of the diatoms, Meridion, Fragilaria, etc., some filamentous Algae present but scattered. Placed some small stones, coated with this material, in a battery jar. Co^'ixids Added. Placed Corixids here and they promptly began feed- ing. When examined surprisingly few diatoms were present, but quan- tities of filamentous algas, Mougeotia and Zygnema. For example, one female A. altemata had the fore part of the stomach packed with filaments of Zygnema as long as the entire mid intestine. This series shows selection in favor of the filamentous algae with dis- crimination against the gelatin embedded diatoms. Culture 17144. (Ankistrodesmus.) History and Diagnosis. Removed the gold fish from a jar in which they had lived for a long time. The jar and rocks were covered with dark-green growths. The water was very green. This was replaced by fresh water. The green growth was dominantly AnkistrodesTnvs falcatus. Some Scenedesmus and diatoms present as well as Cosmarium and Tetraspora. Corixids Added. Twenty nymphs of P. buenoi added. Examined their stomach contents from time to tim.e and they were always full of green chlorophyll material with Ankist7-odesnuis dominant and other Algae present with an occasional rotifer. Green plants are taken first hand and in quantities. Culture 16169. (Botryococcus pure.) History ayid Diagnosis. Botryococcus (a little alga in gelatin.) This culture was pure and growing in Knap's solution. Corixids Added. The bugs always died within a day or so. HUNGERFORD: AQUATIC HEMIPTERA. 247 Culture 16168. (Oscillatoria.) History and Diagnosis. Pure culture of Oscillatoria obtained from water analysis laboratory. No animals in this culture. Corixids Added. Placed A. alfernata here July 28. On August 1 they were observed to work at food gathering. August 8 dissected the Corixids : One male. Digestive tract nearly empty. A brown mass of indeter- minate material in bend of mid-gut. Three females. Tracts nearly full of reddish brown material, indeter- minable. One male. As above, plus considerable number of Oscillatoria fila- ments, some of them still well preserved. Culture A, August 19. (Green pond ooze.) HistoTy and Diagnosis. Gathered some shiny, greenish ooze from the bottom of a mud puddle. This contains various species of Algae, especially the blue greens, and among the free moving Englenge and diatoms. Corixids Added. Several specimens of a small species of Corixid added. In twenty-four hours examined them. Their stomachs were packed with green matter. This consisted of much disorganized unicellular plant cells, Oscillatoria filaments so abundant that they bound the masses together, Englenae and diatoms. This one study would satisfy one beyond any question of a doubt as to the plant origin of their food. Culture B, August 19. (Water Bloom muddy.) History and Diagnosis Gathered some of the green scum from a stag- nant, muddy pool and placed it in a Petrie dish. It was teeming with life. Plants: Chlamydomonas, small species of Englena, large species Englena, diatoms, some Oscillatoria, and a few filaments of an alga. Englena dominant. Animals: Arcella abundant for this genus, Amoeba stuffed green with ingested unicellular plants. A few Paramecium and Heterotrichs. Corixids Added. A. alternata and R. acunmiata placed upon this cul- ture. Examined following day. 3 ^ J? acuminata nearly empty. An- other contained a small ball of yellowish green material in the bend of the mid intestine. This was dissected out entire and resisted separation as if held together by fibrous material. Most of this mass was dis- organized unicellular plant particles, such as noted in the Amoeba. Two clear shafts of some filamentous algae and a membrane of some Crustacea and A, alternata mid-intestine packed full of green material, which re- sisted separation like the above. Mostly bits of greenish material, parts of unicellular plants, many encysted, plenty of bright green cells nearly cir- cular in outline. Red spots of material from disorganizing Englense. Two filaments of Oscillatoria, a couple of diatoms. Most material is of Englena origin, as shown by the fact that fresh Englense still green are abundant, and all stages of disorganized material are to be found. Thus the yellowish granular material can be traced to its unicellular plant origin. 248 THE UNIVERSITY SCIENCE BULLETIN. Culture 17165. (Chironomus.) History aiid Diagnosis. Early in the studies on the boatmen, it was found that hungry bugs would eat Chironomus larvas. In this experiment some sand grains were placed in the bottom of a stender dish, and six Chironomus larvse added. Corixids Added. Placed six P. buenoi here that had been in clear water two days. In two hours only three Chironomus larvae remained. These were fortified beneath sand grains. These midge larvae live in the sludge where Corixids forage. They live in tubes of their own spinning, and occasionally are eaten by the boatmen when the bug comes upon them in the course of its feeding. Culture 1650. (Balanced Aquarium.) History and Diagnosis. Into a circular glass aquarium jar, 9%x8 inches, there had been placed about May 1 one of the Characeae (Nitella) and some clear pond water. The cultux-e came under observation the latter part of May, at which time the Nitella was still a thriving plant, and a small quantity of brownish sediment was upon the bottom of the jar (arranged in a ring perhaps two inches broad around it). The con- tainer was kept nearly full of water by additions from the top. Corixid nymphs in their first instar had hatched from eggs brought in on the Nitella, and continued their development till they became adults. Bits of the carapace of a crayfish bearing eggs of Ramphocorixa acwminata were then added, and this species brought to adult stage. This culture then has considerable interest from the fact that two generations of Corixids were reared in it, one of A. alternata, a clear-pool type, and one of R. acuminata, a stagnant-pool type. The Nitella gradually disintegrated, adding its parts to the deposits in the bottom of the jar, until by July 23 little was left of it. Surveys from time to time disclosed the following in the deposits: Much dis- organized plant matter, a few green spores of Algas, slender empty fila- ments of Algje, some Pediastrum, various diatoms (abundant), and now and then the shell of an Ostracod. Ostracods and snails the only forms of animal life noted. The sediment, notably clear of animal life, adds another feature to the interest of this study. Corixids were observed repeatedly to feed upon the brownish deposit. Corixids were maintained in this jar continuously for nearly four months. Corixids Added. Corixids of two species, A. alternata and R. acum- inata, were reared here. Some of the bugs were maintained here for four months. These bugs obtained their food from the deposits at the bottom. They did not prey upon the Ostracods feeding upon the sides of the jar. CONCLUSION. After carefully checking the results of feeding experiments it is safe to note the following : Corixids sweep in the organic ooze of the pool with its at- tendant populations, both plant and animal, the bulk of the hungerford: aquatic hemiptera. 249 material being of plant origin. The presence of long filaments of Spirogyra, Zygnema and Oscillatoria cannot be accounted for in any incidental manner. The deliberate action of the bug in feeding on the chlorophyll of Spirogyra, as indicated above, is conclusive evidence of the herbivorous tendencies of these creatures. The presence of oligochgetes, nematodes, roti- fers and protozoa indicates that they consume the little ani- mals along with the plant matter. As a basis for the propa- gation of Corixids in artificial quarters, it has been discovered by experiment that a satisfactory food supply can be obtained by grinding the water-soaked leaves of cattail that have laid in the marsh over winter and allowing them to reach a state of balance. A brown flocculent mass is thus produced, in which develop a flourishing population of tiny organisms, both plant and animal. In such a culture Pahnacorixa has been carried from egg to adult. General Review. In the pages preceding an attempt has been made to pre- sent the most important points now known about the biology of water bugs. It has been arranged to most readily determine what is known on any given form. To facilitate future work, the sexual differences of the various groups are figured. These, together with the drawings of the nymphs, permit a ready analysis of a survey of the pond at any time. The general reader is referred to the chapters on Ecologic and Economic Relations, and Form and Function, for matters of popular interest.- In the developmental studies there have appeared certain points of note. The developmental changes of these bugs fall into two categories : First, characters acquired by the adult ; second, characters lost by the adult. Under the first may be mentioned the fact that ocelli, as a rule, when present at all, are adult characters. The toad bug is an exception to this, the nymphs possessing ocelli. The tarsus when two or three segmented is usually an adult charac- ter, the nymphs having one-segmented tarsi. Sometimes the adult possesses more segments in the antennae, as in Corixids. The sexual dimorphism of the adults, such as the asymmetrj^ of male Corixids, etc., is, of course, attained only in the adult. On the other hand, in some instances of adaptation the adults lose structures present in the nymph. The best illus- tration, perhaps, is that of the Belostomatids, which have a single claw on front tarsus. The nymphs have two, one of which may get relatively smaller as later instars are reached. Another case is that of the hind claws of Notonecta and the Corixids. The first instar nymphs have two long claws, while those of adult are setaform and obscured by the swimming fringe. These various changes are fundamental and signifi- cant. In determining phylogenetic relationships, the internal organization, combined with developmental changes, are most important in forms with incomplete metamorphosis. No staple arrangement of the Heteroptera can be made until much more is known of the biology of the group. (250) Preliminary Bibliography to the Biology of Aquatic and Semiaquatic Hemiptera. (Partially annotated.) Abbott, James F., 1912. A New Type of Corixidse {Ramphocorixa hal- anodis N. gen., et. sp.) , with an account of its life history. Can. Ent. (April), pp. 113-120. 1 pi. Abbott, J. F., 1912. An Unusual Symbiotic Relation Between a Water Bug and a Crayfish. Am. Nat., XLVI, pp. 553-556. 1 pi. Abbott, J. F., 1913. Corixida^ of Georgia. Bui. Brooklyn Ent. See. VIII, No. 6, pp. 81-91. Abbott, J. F., 1913. The Variation of Aretocorixa interrupta Say. Wash. Univ. Stud., I, No. 1, pp. 10-21. Adams, C. C, 1913. Guide to Study of Animal Ecology. Macmillan. Aldrovandi, Ulysses. 1618. Historiam Natura . . . de animalibus. Insectes Libri septem), 1st ed., 1602 — is in Latin. Amans, p. Comparaison des organes de la locomotion aquatique. Ann. d. Sc. nat. Zool. (7) VI. Amyot et Serville, 1843. Histoire naturelle des insectes Hemipteres. Paris. (An indispensible work for the Hemipterist.) Annandale, 1907. Notes on the Fauna of a desert tract in Southern India. Pt. II, Insects and Arachnida. Mem. Asiat. Soc. Beng., I, p. 214. Calcutta. Arrows, 1895. Habits of Hydrometra stagnoriim. Science Gossop., II, pp. 201-203. ASHTON, R. I., 1837. On the Wings of Hemiptera. Trans. Ent. Soc. Lond., Ill, p. 95. Figures and described union of wings of No- tonecta. Bachmetjen, p., 1900. Der kritsche Punkt der Insekten und das Ent- stehen von Schmetterlings abberationen. Zeitschr, Ent., V, p. 86-89. {N. cimicoides lived at 16 degrees C.) Bade, E., 1909. Das Susswasser Aquarium. Berlin, 3d ed., pp. 647-657. Balassogls and Puton. Corisa assimilis Fieb. Shower during Storm in Turkestan. Rev. d. 'Ent., I, pp. 22 and 23. Ball, R., 1845. On the Noises Produced by one of the Notonectidse, Rep. of the British, 1845, p. 116. (From other writers.) Banks, Nathan, 1910. Catalog Nearctic Hemiptera-Heteroptera. Am. Ent. Soc. Phil., 1910. B/JiBER, H. G., 1913. Aquatic Hemiptera. Jr. N. Y. Ent. Soc, XXI, p. 29-32. (A paper of popular interest.) Barber, H. G., 1913. Descriptions of two new species of Ochterus Latr., with an arrangement of N. A. species. Can. Ent., XLV, No. 7, p. 213. Baumberger, J. P., 1917. Hibernation: a Periodical Phenomenon. An- nals Ent. Soc. Am., 10, pp. 179-186. (Insects hibernate as adult when food habits permit the proper oviposition at the earliest warm weather.) Baunacke, Walter, 1912. Statifche sinnes organe bei den Nepiden . . . Inaugural Dissertation zur Erlangung der Daktorwiirde der haben philosophischen Fakultat der Koniglichen Universtat zu Greif- swald. (See Zool. Jahrbucher, 89, XXXIV, pp. 179-346. Jena. (251) 252 THE UNIVERSITY SCIENCE BULLETIN. Behn, W., 1835. Deconverte d'une circulation de fluids nutritif dans les pattes de plusieurs Inseces hemipteres. Ann. Sc. natur. Zool. (2) IV. Bergroth, E., 1892. Rheumatobates rileyi. Insect Life, IV, p. 321. Bergroth, E. (For a key to species of Rheumatobates see Ohio Nat., Bergroth, E., 1899. A New Genus of Corixids. Ent. Monthly Mae- (2),X, p. 282. (Tenagobia n. g.) Bergroth, E., 1902. On the Thorax of the Gerrida?. Ent. Monthly Mag (2) 13 (38), pp. 258-260. ^ ^ Bergroth, E., 1906. Svstematische und synonymische Bemerkungen uber Hemipteren. Wien. Entom. Zeit. XXV, pp. 1-12. (Gerris has an unpaired stink gland.) V Berlese, Antonio Gli Insetti . . . 1909. (Figures Notonecta abd., pp. 265 and 299; figures Tibial Combs, p. 248; figures Nepa abdomen, p. 263 ; figures Nepa sexual armature, pp. 306 and 323 ; figures Rana- tra sexual armature, pp. 307 and 323; figures Naucoris abdomen, p. 322; figures Notonecta abdomen, p. 322.) Blanchard, E., 1840. Histcire naturelle des Insectes, vol. 3. Blanchard, E., 1868. Metamorphoses, Moeurs et Instincts des Insectes. Blanchard, R., 1902. Sur la piqure de quelques Hemipteres. Arch, de Parasitol, V. Nr. 1, pp. 139-148. Bordas, L., 1904. Anatomie des s:^andes salivaires de la Nepa cendree Compt. Rend. R. Soc. Biol., LVII, p. 667. Bordas, L., 1905. Les organes reproducteui-s males de la Nepa cendree. C. R. Soc. Biol., LVIII, p. 382. Paris. Borner, C., 1904. Zur Systematik der Hexapoden. Zoolog. Anz., XXVII, p. 511-533. Leipzig. (Makes 4 suborders of Hemiptera.) Brandt, A., 1869. Beitrage zur Entwlcklungsgeschichte der Lebellu- liden und Hemipteren. Mem. Acad. Sci. St. Petersbourg, (VII) 13. Brandt, E., 1878. Vergleichend anatomische Untersuchungen iiber das Nervensystem der Hemipteren. Horas Soc. Ent. Ross., 14, pp. 496-505. Brauer, 1909. Die Siiss Wasserfauna Deutschlands, VII, p. 37-110. Brimley, C. L., 1905. (For notes on Walking of B. griseus see: Ent. News, XVI, p. 88.) Britton, W. E., 1911. A Hemipterous Fisherman. Ent. News, XXII, pp. 372-373. (Lethocerus mnericana.) Brocher, F., 1909. Recherches sur la respiration des insectes aquatiques adults. Annals Biol. Lacustre, IV, p. 9; V, pp. 218-258; VII, pp. 5-39. Brocher, F. 1910. Observations biologiques sur quelques D'pteres et Hymenopteres dits aquatiques. Annales. Biol. Lacustre Bruxelles, IV, p. 170-186. (See, also, Zool. Jahr., 33 Band, 2 Heft.) Brocher, Frank, 1911. La ponte, the oeuf et le larve des Velies in Obser- vations Biologiques sur nnelqnes in<^ectes aquatiques. Ann. Biologic. Lacustre, IV, p. 369. (Eggs placed in heap on emergent vegetation above surface.) Brocher, Frank, 1911. La ponte I'oeuf et la larve du Limnobates. Ann. Biologie Lacustre, IV, p. 367. (Figures hatching egg and shows the "egg burster,") Brocher, Frank, 1911. Les phenomenes capillaires, Leur importance dans la biologie aquatique. Annales Biologie Lacustre Brussels, IV, 89-138. hungerford: aquatic hemiptera. 253 Brocher, F., 1913. E'Aquarium de Chambre. Introduction a 1' etude de I'Histoire Naturelle. Paris. (A fine book, much new material.) Brulle, a., 1836. Histoire naturelle des Insectes, vol. 9. Bruyant, Charles, 1894. Sur un Hemiptera aquatique stridulant Si- gara minutissima Compt. Rend., CXVIII, p. 299. BuDGEN AND GoODMAN, 1893-'94. Gerris najis-larva and habits. P. Croy- den Club. (Cannot locate this.) Burmeister, a., 1835. Handbuch der Entomologie. 2 vols. Berlin, v"' Butler, E. A., 1893. On the Habits of Mesovelia furcata Muls. & Key. Ent. Mag., XXIX, pp. 232-236. (A fine paper on habits.) Butler, E. A., 1918. On the Association between the Hemiptera, Heteroptera and vegetation. Ent. M. M., LIV, June. p. 132. (Nepa and Ranatra lays eggs in leaves of Alisma.) Bueno, J. R. DE LA Torre, 1902. Some Preliminary Notes on the Early Stages of Notonecta. Proc. N. Y. Ent. Soc, X; p. 250. (Eggs upon the stem.) Bueno, J. R. de la Torre, 1902. Notonectidje of New York. Jr. N. Y. Ent. Soc, X, p. 230-236. (Some good general notes. Thinks Plea is a vegetable feeder.) Bueno, J. R. de la Torre, 1903. A Day's Collecting in February. Can Ent., XXXV, p. 123. (Gerris eating a Perlid, Capnia.) Bueno, J. R. de la Torre, 1903. Brief Notes Toward the Life History of Pelacoris femorata. Pal. B., Jr. N. Y. Ent. Soc, XI, pp. 166-173. J'Bueno, J. R. DE LA Torre, 1903. Notes on the Stridulation and Habits of Ranatra fusca. Pal. B., Can. Ent., XXXV, p. 235-237. Bueno, J. R. de la Torre, 1905. The Hemiptera Heteroptera in "Ameri- can Insects." Can. Ent., XXXVII, p. 389. Bueno, J. R. de la Torre, 1905. The Three Ranatras of the N. E. U. S. Can. Ent., XXXVII, p. 187. (Keys out 3 species.) Bueno, J. R. de la Torre, 1905. The Genus Notonecta in America North of Mexico. Jr. N. Y. Ento. Soc, 13, p. 143-167. (Key to species and biological notes.) Bueno, J. R. de la Torre, 1905. Notes on Collecting, Preserving and Rearing Aquatic Hemiptera. Can. Ent., XXXVII, p. 138. Bueno, J. R. de la Torre 1905. The Tonal Apparatus of Ranatra quadri- dentata Stal., Can. Ent., vol. 37, p. 85. (Several sketches.) Bueno, J. R. de la Torre, 1905. Notes on Hydrometra martini Kirk. (L'neata Say), Can. Ent. XXXVII, pp. 12-14. (Gives rearing notes and figures male genitalia of H australis and H. martini.) Bueno, J. R. de la Torre, 1905. Nerthra styqica Say and some notes on the family Gelastocoridae. Ohio Nat., V, pp. 287-291 (with text figures) . -^f^^BuENO, J. R. DE LA ToRRE, 1906. Ways of Progression in Water Bugs. Ent. News., XVII, pp. 1-4. BuENO, J. R. DE LA ToRRE, 1906. Life History of Belostoma fluminea. Can. Ent., XXXVIII, pp. 189-197. (Includes description of Instars.) BuENO, J. R. DE LA ToRRE, 1906. Life History of Ranatra quadridentata. Can. Ent., XXXVIII, pp. 242-252. Bueno, J. R. de la Torre, 1907. Diplonychus, Laporte (Hydrocyrius, sn^noia) and its relation to other Belostomid Genera. Can. Ent., XXXIX, Oct., pp. 333-341. ^yBuENO, J. R. DE LA ToRRE, 1907. On Rhagovelia obesa Uhler. Can. Ent., XXXIX. pp. 61-64. 3 figs. (Describes and figures structure of middle tarsus.) 254 THE UNIVERSITY SCIENCE BULLETIN. BuENO, J. R. DE LA ToRRE, 1908. Broken Hemelytra in certain Halo- batinffi. Ohio Nat., IX, pp. 389-392, 4 figs. (Figures broken hemelytra and records this habit of self mutilation for Rheumato- bates and Trepobates.) BuENO, J. R. DE LA ToRRE, 1908. Concerning the Notonectidae and some recent writings on Hemipterology. Can. Ent., XL, p. 211. (Says Delcourt has solved food problem by feeding mosquito wrigglers.) BuENO, J. R. DE LA ToRRE, 1909. The Notonectid genus Buenoa, Kirkaldy. Keys 3 species.) BuENO, J. R. DE LA ToRRE, 1910. Life History of Microvelia americana Uhl., Can. Ent., XLII, p. 176. BuENO, J. R. DE LA ToRRE, 1911. The Gerrids of the Atlantic States (Subf. Gerrinae). Tran. Am. Ent. Sac, XXXVII, No. 3, pp. 243- 252. BuENO, J. R. DE LA ToRRE, 1913. Remarks on the Distribution of Heteroptera. Can. Ent., XLV, p. 107. (Gerris rufoscutellatus Latr. widest distribution of all Hemiptera save Nezara veridula ) BuENO, J. R. DE LA TORRE, 1915. Phototropism in Heteroptera. Bui. Brooklyn Ent. Soc, IX, p. 90-96. BuENO. J. R. DE LA ToRRE, 1915. Heteroptera in Beach drift. Ent. News, XXVI, p. 274-279. BuENO, J. R. DE LA ToRRE, 1916. Veliinas of Atlantic States. Bull. Brook. Ent. Soc, XI, p. 52. (Keys and biology.) BuENO, J. R. DE LA ToRRE, 1917. Aquatic Hemiptera, a Study in the re- lation of Structure to Environment. Ann. Ent. Soc. Am., IX, p. 353-65. BuENO, J. R. DE LA ToRRE, 1917. Life History of Gery-is remigis Ent. News, XXVIII, May, pp. 201, 208. BuENO. J. R. DE LA ToRRE, 1917. Life History and Habits of the Margined "Water Strider Gerris marginatus Say. Ent. News, XXVIII, p. 295. BuENO, J. R. DE LA ToRRE, 1917. Life History of the Northern Micro- velia. Microvelia borealis Buen. Ent. News, XXVIII, p. 354. 1 plate. (Gives four nymphal instars.) Calvert, P. P., 1898. The first filling of the trachese with air. Ent. News, IX, No. 3, p. 73. (In Odonata comes with first molt, V2 hour after hatching.) Camerano, Lorenzo, 1879. Gli Insetti. Introduzione alio studio dell y 'entomologia. Torins e Roma. (Have not seen.) ^ Carpenter, G. H. The Stridulation of Corixa. Irish Naturalist, III, No. 12, p. 253. Carpenter, G. H., 1899. Insects, their Structure and Life. Dent & Co. London (p. 188-191). Carpenter, G. H. Report on the marine Hemiptera (Halobates) col- lected lay Professor Herdman in Ceylon in 1902. R. Soc. Rep. Pearl Oyster, V. pp. 151-156. 1 plate. London. (Fig. male and female genitalia of H. Herdmani.) Champion, G. C, 1897-1901. Biologia Centrali Americana. Rhynchota, Heteroptera. (Water bugs in vol. II.) CoMSTOCK, J. H., 1887. Note on Respiration of Aquatic Bugs. Am. Nat., XXI, p. 577. CoMSTOCK, J. R., 1916. A Manual for the Study of Insects, by Comstock, J. H. and Comstock, Anna Botsford, 14th ed. Comstock Pub. Co., Ithaca, N. Y. Cowan, Frank, 1865. Curious Facts in the History of Insects. Lippin- cott. (See page 275, account of C. mercenaria.) hungerford: aquatic hemiptera. 255 Crampton, C. C, 1916. The Lines of Descent of the Lower Pterygotan Insects, with Notes on the Relationships of the Other Fornjs. Ent. News, XXVII, p. 301. (4 sub orders, Notonectid = Euhemiptera ; Capsid = (Mesohemiptera) ; Pentatomid = Metahemiptera ; Berytid = Apohemiptera.) Dalhne Uber die Kaltebestandigkeit der Wasserwanzen Zeitschr f. Naturwiss, LXXXI, p. 199. Leipzig. {N cinerea and N. glaiica frozen in ice.) Dahl, F., 1884. Beitrage zur Kenntnis des Baues und der Funktionen der Insekten beine. Archiv f. Naturgesch., 50, pp. 146-193. Delcourt, a., 1907. De la necessite d'une revision des Notonectes de France. Feuille jeun. Nat., XXXVII, p. 198. Paris. Delcourt, A., 1907. Quelques observations sur la variabilite de Noto- necta glauca C. R. Soc. Biol., LXII, p. 11-13. Paris. (Gives egg- laying of species.) Dexcourt, a., 190 — . Recherches sur la variabilite du genre Notonecta. Bull. Scientif. Fr. Belg. (7), XLIII, p. 373. (Gives biology.) Dexcourt, a., 1908. De I'influence de la Temperature sur le developpe- ment des Notonectes. C. R. Assoc, franc. Avanc. Sc, XXXVI, p. 244. (Reims.) DiMMOCK, G., 1886. Belostoniatidae and other fish destroying bugs. In Ann. Rept. Fish and Game Comm. {Zaitha flimiinea female places eggs on her own back.) Distant, Wm L., 1900. On the Egg Carrying Habits of Zaitha fluminea. The Zoologist (4), IV, pp. 93-94. (London.) Distant, W. L. Oriental Rhynchota Heteroptera. Ann Mag. Nat. Hist. (8), III, pp. 491-507. (London.) Distant, Wm. L., 1903. Report on Rhynchota Pt. I, Heteroptera. Fasci- culi Malay Zool. I., pp. 219-272. PI. XV-XVI. (London.) (Amorgius indicus egg laying.) Dog, Walter, 1909. Metamorphose der Respirations ortrane bei Nepa cinera. Greifswald-Mitt. Natw. Ver. 40, (1908, 1909, p. 1-55). 2 plates. DOHRN, A., 186,5. De anatomia Hemipterorum (Vratislaviae 1865). (From Berlese. Have not seen this.) DOHRN, A., 1866. Zur anatomie der Hemiptera. Stettin Entom. Zeit. 27, pp. 321-352. Douglas, J. W. (For Note on Gerris lacustns hibernating far from water, see Ent. M. M., XIX, p. 20.) Douglas, J. W., 1864-1868. On some peculiarities in the development of Hemiptera Heteroptera. Ent. Month. M. Ill, p. 26, p. 200; IV, p. 96; VI, 4-6. Douglas, J. W. and Scott, J., 1865. British Hemiptera. (Ray Soc. London.) Drake, Carl J., 1914. Food of Rana Pipiens. Ohio Nat. Mar. 1914. (A few Gerrids and one Notonectid taken.) Drake, Carl, 1915. Life History Notes on Gerris coriformis and Lim- nogonus hesione Ohio Nat., XV, p. 503. Drake, Carl J., 1917. A Survey of the North American Species of Merragata. Ohio Jr. of Sci., vol. XVII, No. 4. DuFOUR, Leon, 1821. Anatomie de la Ranatre lineaire et de la Nepe cendree. Ann. gener. d. sci. phys. Bruxelles, 7. DuFOUR, Leon, 1833. Recherches anatomique et philosophiques sur les Hemipteres, accompagnees de considerations relatives a I'histoire naturelle et la classification des insectes. Paris, 1833. 256 THE UNIVERSITY SCIENCE BULLETIN. DuFOUR, Leon, 1834. Resume des recherches anatomiques et physio- logiques sur les Hemipteres. Ann. Sc. Nat. Zool. (2), 1. DuFOUR, Leon, 1863. Essai monographique sur les Belostomides. Ann. Soc. Entom. de Fr., 1863, pp. 373, 400. DuFOUR, Leon. Essai sur les Belostomides. Ann. Soc. Ent. Fr. (4), IV, p. 219. Ege, R. On the respiratory function of the air stores carried by some aquatic insects. Zeitschrift fur Allegempine Physiologie. Jena XVII, 81-124. Embody, G. C, 1912. A Preliminary Study of the Distribution, Food and Reproductive Capacity of Some Fresh Water Amphipods. In- ternationale Revue der gesamten Hydrobiologie. (Back-swimmers eat Amphipods. Enock, Fred, 1900. On the oviposition of Ranatra linearis, Ent. Month. Mag. XXXVI; p. 161. London.) (See also Proc. Ent. Soc. London. 1900, p. XII. Erb, L., 1883. Uebersicht der Morphologic der Hemipteren (Halbflugler) nebst einer etwas eingehinderen Erorterung derselben an Vertretern der wichtigsten Familien dieser Insekten ordnung (Progr, Steyr. Ober-Realschule, 8, pp. 3-38. (Not available to writer.) \y EssENBERG, CHRISTINE, 1915. Habits of Water Strider Gerris remiges. Jr. Animal Behavior. Camb. V., pp. 397-402. ESSENBERG, CHRISTINE, 1915. Habits and Natural History of the Back- ^ swimmers. Jr. Animal Behavior. Camb. V., p. 381. Fabre, J. H. Souvenirs entomologiques series 7. Etudes sur I'instinct et le moeurs des insectes. Paris, p. 260 (6th ed.) (Meager informa- tion here.) Fletcher, J. E., 1884. A Water Insect Attracted by Glass (Gerris lacustris ) Ent. XVII, p. 21. Forbes, S. A., 1880. The Food of Fishes. Bull. 111. State Lab. Nat. Hist. I. Forbes, S. A., 1888. Studies of the Food of Fresh Water Fishes. Bui. 111. State Lab. N. H., III. Forbes, S. A., 1914. Fresh Water Fishes and Their Ecology. 111. St. Lab. Nat. Hist. Urtana, 111. * Frisch, J. L., 1727. Beschreibung, von allerlen Insecten in Teutsch- land VI. FURNEAUX, W., 1896. Life in Ponds and Streams. London and N. Y. Fuss, C, 1861. Verhandl. d'Siebenburg Ver. zu. Hermannstadt, XIII, p. 4. (Gives egg laying of Corixa Geoff royi.) Gadeau de Kerville, 1902. L'accoupliment, des Hemipteres Bull, Soc. Ent. Fr. 1902, p. 67, Figs. 1 to 4. (Notes mating of Gerris najas.) Garman, H., 1888. Bull. 111. State Laboratory of Nat. Hist. Ill, p. 174. Garner, R.. 1865. On the vocal organ of the Corixa, an Aquatic Insect. Rept. British Assoc. Note, P- 122. de Geer, Baron Karl, 1778. Abhandlungen zur Geschichte der Insekten. 5 vols. Niirnberg (see vol. 3, p. 250.) Geise, O., 1883. Die Mundtheile der Rhynchoten. Arch. Naturgesch Jahrg., 49, Bd. 1. (Long, section of Corixid head.) Geoffrey, M., 1774. Histoire abregee des Insectes dans laquelle ces an maux sont ranges suivant un ordre methodique. Vol. 1. Paris. (See, also, 1764, p. 474-481.) GiRARD, Maurice, 1885. Traite elementaire d'Entomolo^ie III. (Colored picture Nepa, Naucoris, Corixa, Ranatra, N. glauca. hungerford: aquatic hemiptera. 257 Glover, Townsend, 1876. Manuscript Notes from My Journal, or Illus- trations of Insects, Native and Foi'eign. Hemiptera, Washington. (A unique and exceedingly valuable work digesting the systems of classification and notes on biology. Rare. Available to writer in both Cornell and KansaS departmental libraries. Green, E. E., 1901. Biologic notes on some Ceylonese Rhynchota. Ento. XXXIV, p. 113., Fig. 1-4. (London.) {Amorgius indicus egg laying.) Griffini, 1894. Gli Insetti Acquaioli. (Turin.) Griffini, 1904. Gli Insetti Acquaioli. (Turin, 1894.) Griffini, A. Catalogus synonimicus et topographicus Rhynchotorum aquatilium hucusque in Italia repertorum. (Gives bibliography of Aquatic Rhynchota.) Haase, 1884. Zeitschr. f. Ento. Breslau. Hagermann, J. Biologie der bekanntesten wasserwanzen. Natur. Mun- chen, IV, p. 151-152. (Cannot locate this reference.) Hagermann, Johannes, 1910. Beitrage zur Kenntnes von Corixa. Zool. Jahr. Jena (Abt. f. anat.), XXX, pp. 373-426. Hahn, C. W., 1853. Die wanzenartigen Insekten abgebildet und beschrieben. (Fortgef. v. Herrick-Schaffer.) Vol. 9. Nurnberg. (Figures sexes of Zaitha, many colored plates.) Handlirsch, a. 1900. Neue Beitrage zur Kenntniss der Stridulations organe bei den Rhynchoten. Verb. Zool-bot Ges. Wien., 1, pp. 555- 560, figs. 1 to 7. (Gives Naucoris cimicoides.) ,^ANDLIRSCH, A. 1900. Zur Kenntniss der Stridulation organe bei den Rhynchoten. Ein morphologisch biologischer Beitrag. Ann. K. K. Naturhist. Hofmus Bd., XV, Heft 2, Wien 1900, p. 127. (Gives Corixa and Sigara.) Hart, C. A., 1895. Entomology of the Illinois River and Adjacent Water. Bull. 111. State Lab. Nat. Hist., IV. Harvey, G. W., 1907. A Ferocious Water Bug. Can. Entom., XXXIX, pp. 17-21. (Life History Notes on Pedinocoris macronyx.) (See,- also, W. Proc. Ent. Soc, VIII, p. 72-75.) Hausmann, S. F. L., 1803. De animamalium ex sanguineum respira- tione. Hanover. (Have not seen.) Heidemann, Otto, 1901. Eggs of Halobates in Papers from the Hop- kins Stanford Galapagos Expedition, 1898, p. 362. (See, also, Proc. Wash. Acad. Sc, vol. Ill, p. 364.) Heidemann, 0., 1905. Hydrometra martini. Jr. N. Y. Ent. Soc, XIII, p. 102. Heidemann, Otto, 1896. Winged Specimen of Rheumatobates rileyd Proc. Ento Soc. Wash., Ill, No. 5, pp. 317-318. Heidemann, O., 1911. Eggs of N. A. species of Hemiptera Heteroptera, Proc. Ento. Soc. Wash., 13, p. 128-140, pi. IX-XII. (Says eggs not described for Saldids, Gelastocorids, Gerrids, Mesoveliids, Hebrids, Ochterids.) Hentschel, Dr Ernst, 1909. Das Leben des Suswassers. (Little value.) Hewitt, C. Gordon, 1906. Some observations on the Reproduction of the Hemiptera Cryptocerata. London Trans. Ent. Soc, 1906, pp. 89-90. (Egg laying and mating of Corixa. Mating of Nepa cinerea.) Heymons, R., 1899. Der morphologische Bau des Insecten Abdomens. Zool. Ctrbl., VI, p. 357. Heymons, R., 1899. Beitrage zur Morphologie und Entwicklungsges chichte der Rhynchoten. Nova. Acta. Acad. Leop. Carol., 74, pp. 349-456. (Fine paper.) 17 — Sci. Bui. — 1669 258 THE UNIVERSITY SCIENCE BULLETIN. Heymons, R., 1906. Ueber einen apparat zum Oeffnen der Eischale bei den Pentatomiden. Zeitschr. Wiss. Insektenbiol, II, pp. 73-82. (De- vice similar to what I find in Gerris, Hydrometra, Hebrus, Micro- velia.) Heymons, Rich., 1896. Die mundtheile der Rhynchota. Entom. Nachr., XXII, No. 11, pp. 173, 175. Holmes, S. J., 1904. Phototaxis in Ranatra Jr. Comp. Neur and Psych. XV, p. 305. Holmes, S. J., 1907. Observations on the young of Ranatra. Biol. Bull. Woods Hole 12, pp. 158-164. (Behavior studies.) Holmes, S. J., 1911. The evolution of Animal Intelligence, 1911. Hoppe, Julian, 1911. Die atmung von Notonecta glmica Zool. Jahrb. 89, XXXI, 189-244. (Gets different results from Brocher.) HoRVATH, 1873. Corixa Frivoldskyi Horv. sine neue art von Pest., Berl. Ent. Zeitschr, XVIII, p. 336. Howard, L. O., 1900. Hibernation of Electric Light Bug in. U. S. Dept. Agri. Div. Ent. Bull. 22, n. s., p. 108. (Washington.) (B. ameri- cana taken under ice.) Howard, L. O., 1912. The Insect Book. Doubleday, Page & Co. Hungerford, H. B., 1917. The Egg Laying Habits of a Backswimmer. Buenoa margaritacea Ent. News, XXVIII, pp. 174-183, 1 pi. Hungerford, H. B., 1917. Notes Concerning the Food Supply of Some Water Bugs. Science, N. S. XLV, No. 1,162, pp. 336-337. Hungerford, H. B., 1917. Food Habits of Corixids. Jr. N. Y. Ento. Soc. XXV, No. 1, pp. 1-5, 1 pi. Hungerford, H. B., 1917. The Life History of the Backswimmer, Notonecta undtilata Say. Ent. News, XXVIII, pp. 267-278, 2 pi. Hungerford, H. B., 1917. The Life History of Mesovelia mulsanti White. Psyche, XXIV, No. 3, pp. 73-84, 1 pi. Hungerford, H. B., 1917. Life History of a Boatman. Jr. N. Y. Ent. Soc, vol. XXV, No. 2, June, pp. 112-122, 1 pi. Hungerford, H. B., 1918. Notes on the Oviposition of Some Semi- aquatic Hemiptera (Hebrus Salda, Lamprocanthia). Jr. N. Y. Ent. Soc. XXVI, No. 2, Mar., pp. 12-18, 1 pi. Hungerford, H. B., 1918. Concerning the Oviposition of Notonecta. Ent. News, XXIX, pp. 241-245, 1 pi. IMHOF, O. E., 1901. Mecanisme de la fermeture des ailes des Hemip- teres peu communs de M. Maur Royer. Bull. Soc. Entom. Fr. 1901, No. 10, pp. 191-192. Jewell, Minnie E. Survival of Certain Aquatic Animals in the ab- sence of Oxygen under different conditions of acidity and alka- linity. (Read before Ecol. Soc, Dec, 1916, in N. Y.) JOHANSEN, F., 1908. Denmark Ekspeditionen til Gronlands Nordontkyst, 1906-1908. (Copenhagen.) Meddelelser om Gronland, 337, V. 321- 337. (Fresh Water Life in Northeast Greenland.) (Have not seen this.) JOHANNSEN, O. A. & J. F. Lloyd, 1915. Genera of Plancton organisms of the Cayuga Lake basin. Limnological Lab., Ithaca, N. Y. (Used to aid in determining stomach contents of Corixids.) Keys, 1895. ^pophilus monnairii, habits. Ent. Mag. XXXI, p. 136. Kellogg, V. L., 1914. American Insects. H. Holt. Kirby, 1892. Text Book of Entomology. (London.) (Water Bugs, pp. 206-208.) Kiritshenks, a. N., 1911. Notices sur les Hemipteres Heteropteres de la faune russe. Rev. Russe. Entom. XI, pp. 40-43. (Petersburg.) hungerford: aquatic hemiptera. 259 KiRKALDY, G. W., 1896. Notenecta, oviposition. See Pro. Ent. Soc. Lon- don, 1896, p. 27. (N. glauca eggs on stem.) KiRKALDY, G. W., 1897. Notonectidae, Revision of. Pt. LI. Trans. Ent. Soc. London, 1897, pp. 393-426. (Mentions difficulty of rearing.) KiRKALDY, G. W., 1908. Notes on Corixidae, No. 1. Can. Ent., vol. XL, pp. 117-120. (Table to genera.) KiRKALDY, G. W., 1898. An Economic Use for Water Bugs. Ent. Mo. Mag. XXXIV, p. 173. (Review^s notes on Corixa and Notonecta eggs as food in Mex.) KiRKALDY, G. W., 1898 to 1908. A Guide to the Study of British Water Bugs. (Ent. XXXI, pp. 180, 203; XXXII, pp. 3, 108, 151, 200, 296; XXXVIII, p. 173, 231; XXXIX, pp. 60, 79, 154; XLI, p. 37. (A splendid series on Biology.) KiRKALDY, G. W., 1899. (For desc. of egg of N. americana see Rev, d'entom.. Franc, XVIII, p. 94. {N. americana undulata Say, Ent. XXXII, p. 79.) KiRKALDY, G. W., 1899. An Economic Use for Water Bugs. Ent. M. M. (2) IX, (34), p. 173. (Corixa eggs in Mexico.) KiRKALDY, G. W., 1900. Recent notes on Hydrometra martini Kirk. lineata Say. Ent. XXXIII, 1900, p. 175. y KiRKALDY, G. W., 1901. The Stridulatory organs of water bugs, especi- "^ ally of Corixidffi. Jr. Quekett Micro. Club (2), vol. VIII, pp. 33- 46, pi. 3-4. y KiRKALDY, G. W., 1904. Uber Notonectiden. Wien. Ent. Zeit., XXIII- VIL KiRKALDY, G. W., 1906. Gerridae and others. Catalogue of genera. Tran. Am. Ent. Soc, XXXII, p. 153. KiRKALDY, G. W., 1908. A synonymic Note on Certain Belostomidse. Can. Ent. XL, p. 164. (Response to Bueno in Can. Ent. XXXIX, p. 333. KiRKALDY and Bueno, 1909. Catalog of Aquatic and Semiaquatic Hemip- tera. Proc Ento. Soc. Wash., X, pp. 173-215. Knauthe, K., 1907. Das Siisswasser, chemisch, biologische und bakte- riologische Untersuchungsmethoden unter besonderer Berucksichti- gung der Biologie und der fischeriewirtschaftlichen. Praxis. Neu- damm. (Have not seen.) Kraepelin, K., 1882. Ueber die Mundwerkzeuge der saugenden Insekten. Zoolog. Anzeiger, 1882, pp. 574-579. KrecKer, F. H., 1919. Fauna of rock bottom ponds. Ohio Jr. Sci., Columbus, XIX, p. 427. Kulgatz, Th., 1911. Die aquatilen Rhynchoten Westpreussens Bericht d. westpreuss. Bot. Zool., ver. XXXIII, p. 175. Kunckel, d'Herculais J., 1866. Recherches sur les organes de secretion chez les Insectes de I'ordre des Hemipteres. Compt. rend. Acad. Sci., LXIIL Kunckel, d'Herculais, 1895. Etude comparee des appareils odorifiques dans les differents groupes d' Hemipteres heteropteres. Comt. Rend. Acad. Sci., CXX. Lachlan, M. For Notes on Halobates see Ent. M. M., VII, p. 208. Laker, A. G., 1879. Note on the Habits of Ranatra lincearis. Ent. 12, p. 142-145. (Swimming and feeding.) Lamark, 1816. Histoire naturelle des animaux sans vertebres. Vol. III. (Paris.) 260 THE UNIVERSITY SCIENCE BULLETIN. Lambertie, M., 1904. Note sur quelques Hemipteres nonveaux ou rares de la Geronde. Proc. Verb. Soc. Linn. Bordeaux LVIII, pp. 239-240. (Pelogoniis viarginatus Latr. in moist places.) Lampert, Dr. Kurf, 1899. Das Leben der Binnen gewasser. Leipzig. (P. 138-144, Water Bugs.) Lange, D., 1904. Flight of Corixa, Can. Ent. XXXVII, p. 364. (Thou- sands on sprinkled asphalt pavement.) Latreille, p. a., 1802. Histoire naturelle generale et particuliere des crustaces et des Insectes. Vol, XII. Latreille, P. A., 1803. Nouveau Dictionnaire d'histoire naturelle ap- plique aux arts, principalement a I'agriculture et a V economic rurale et domestique. Lefebvre, 1903. Observations sur 1' anatomie macroscopique de I'appareil salivaire de Nepa cinerea. Ann. Soc. Scientif. Brux., XXVII, p. 192 (Louvain) . •^ Leidy, Joseph, 1847. History and anatomy of the hemipterous genus Belostoma. Journal, Acad. Sci. Phila. (2), I, pp. 57-67. \/ LOCY, Wm a., 1884. Observations on the pulsating organs in the legs of certain Hemiptera. Am. Nat. XVIII, p. 14. (Concludes that these are distinct from musclature and that they influence circulation. Water bugs studied.) -yLocY, W., 1884. Anatomy and physiology of the family Nepidae. Am. Nat., 1884, p. 250. Low, F. For nocturnal flight of Corixa falleni Fieb., see Verh. Zool. Bot. Ges. Wein., XVI, p. 946. Lucas, N. J., 1900. Ranatra linearis, habitat. See Ento. XXXIII, p. 181. (London.) Lundbeck, W., 1914. Some remarks on the eggs and egg deposition of Halobates. Mindeskrift fur J. Steenstrup XX\II, Kohen havn., p. 13. (Report on collection of Steenstrup in Museum of Copenhagen.) LuTZ, F. E. Factors in Aquatic Environments. Jr. N. Y. Ento. Soc, XXI, pp. 1-4. LuTZ, F. E., 1918. Field Book of Insects. Putnam. Lyon, Mary B., 1915. The Ecology of the Dragon Fly Nymphs of Cas- cadilla Creek. Ent. News, XXVI, pp. 1-13. (Corixa nymphs eaten by dragon fly nymphs.) VMarshall, W. E. and Severin, H., 1904. Some points in the Anatomy of Ranatra fusca P. Beauv Trans. Wise. Acad. XIV, p. 487, plates XXXIV-XXXVI. Martin, Joanny, 1895. Origine et Formation de foux stigmates chez les Nepidae. Bull. Mus. H. N., Paris, 1895, p. 133. Martin, J., 1896. (Belostoma lamella supposed to be respiratory in larva see; Bull. Mus. N. H., Paris, 1896, pp. 234-235. Martin, J. O., 1900. A Study of Hydrometra lineata. Can. Ent., XXXII, Mar., pp. 70-76. (Life history, drawing of egg, etc.) Mason, Jas. Eardley. Aquatic habit of Salda. Ento. M. M., XXV, p. 236. (S. lateralis clung to plants and remained submerged beneath the tide.) Matheson, Robert, 1907. Belostoma eating a bird. Ent. News, XVIII, p. 452. (Publication of a letter from P. Lavvrence repoi'ting B. Amencana attacking a woodpecker.) Matheson. Robert and Crosby, C. R., 1912. Aquatic Hymenoptera in America. Annals Ent. Soc. Am., V, pp. 65-70. (With figures). (Proctotrypids from eggs of Gerris remigis and Notonecta.) Maulik, S., 1916. Respiratory system of Nepa linerea Linn. Jr. of Zool. Research, Vol. I, No. 2, p. 41. hungerford: aquatic hemiptera. 261 Mayr, Gustav, 1871. Die Belostomiden. (Verh z. b. Wien., XXI, pp. 399-440. (A monograph, includes key to genera and species and describes nymphs.) Meinert, 1887. Vandlberne, Hydronietridffi deres Farden og. Leven. Soertryk of Entomol. Meddelelser, I, p. 95. Meneville, Guerin M., 1829. Iconographil du regne animal de G Cuvier, 1829. (Vol. XIII, water bugs and Vol. XIV, colored plates of water bugs.) Merian, Marie Sybille, 1726. Dissertation sur la generation et les transformations des insectes de Surinam. La Haye (Id. Paris, 1771). Miall, L. C, 1895. The Natural History of Aquatic Insects. Macmillan. (For aquatic hemiptera see ch. X, p. 346.) Moleyre, L. Recherches sur les organes der vol chez les Insectes de r ordre des Hemipteres. Comptes rend, de I'Acad. des Sc, XCV. Montgomery, Thomas H., 1900. Notes on the Genital Organs of Zaitha. Am. Nat., XXXIV, pp. 119-121. 2 fig. (Male Zaitha 5 follicles. Belostoma 1 follicle. Zaitha related more to Nepa than to B. in this.) MouFFET, Thomas, 1634. Insectorum Theatrum (Insectorum sine mini- morum animalium Thsetrum.) See p. 320. Needham, J. G., 1903. New York State Museum Bulletin 68. (For a note on Corixa eaten by a nymph of the dragon fly Libelhda pul- chella, see p. 210.) Needham, J. G., 1903. (For Notonecta eaten by Aeschna constricta a dragon fly nymph, see N. Y. St. Mus. Bull. 68. Needham, James G., 1907. The eggs of Benacus and their hatching. Ent. News, XVIII, pp. 113-116, pi. 2. (Splendid photographs of eggs and hatching nymphs.) Needham, J. G., 1908. Notes on the Aquatic Insects of Walnut Lake. Rept. Board. Geol. Surv. Mich, for 1907. Needham, J. G., 1912. Fish Culture for Farmers. Farmers Magazine, June, 1912. Needham, James G. and Lloyd J. T., 1916. The Life of Inland Waters. Comstock Pub. Co. Needham, J. G., 1917. The Insect Drift of Lake Shores. Can. Ent. (Apr.) p. 120-137. (Saldids and Gerrids.) Needham, James G., 1918. Aquatic Insects in. (Fresh Water Biology, ch. XXVII, pp. 893-896.) wNicHOLS. Corixa. The discoverer of its stridulation. Irish Natural., *^ IV, p. 79. NOWROJEE, D., 1911. Life Histories of Indian Insects II. Some aquatic Rhynchota and Coleoptera in.: Memoirs of the Dept. of Agri. in India. Vol. II, No. 9, Ento. Ser. (London.) (Ranatra and a Notonectid, colored plate.) Oliver, M., 1811. Encyclopedie Methodique. Histoire Naturelle In- sectes, VIII. (Page 386 gives splendid habits of Notonecta.) Olsen, C. E., 1917. Concerning Gerris remigis Bull. Brooklyn. Ent. Soc, XII, p. 21. Ormerod, E. a., 1889. Ranatra linearis attacking small fish, Ent., XI, pp. 95, 119-120. OsBURN, Herbert, 1894. Phylogemy of Hemiptera. P. Ent. Soc. Wash., Ill, p. 185. (Considers water bugs highly specialized.) Packard, A. S., 1873. Our Common Insects. Packard, A. S., 1881. Half Hour Recreations in Natural History, Bos- ton, 1881. (See ch. 6, Insects of the Ponds and Streams.) 262 THE UNIVERSITY SCIENCE BULLETIN. Paiva, C. a., 1907. Notes on some Indian Hemiptera. Rec. Ind. Mus., I, pp. 174-176. Palumba, 1891. Gli amori del 1' Hydrometra stagnorium Revist. Ital. Sc. Nat., XI, p. 1. Parshley, H. M., 1917. Insects in Ocean Drifts. Can Ent. Feb. 1917. Parshley, H. M., Fauna of New England. List of H. Heteroptera. Boston Soc. Nat. Hist. VII. Patton, W. H., 1896. Rank of Water Bugs. Ent. News, VII, p. 202. (Considers water bugs highly specialized.) Pedaschenko, D., 1891. Sur la formation de la bandelette germinative chez Nontenecta glauca (in Russian) Rev. Sc. Natur. St. Petersbourg, I. (Not seen. Ref. from Belese.) Le Peletier de St. Fargeau et Serville, 1825. Encyclopedie Method- ique, Entomologie, X. (Paris.) Pettet, R. H., 1902. The Egg of the Water Scorpion. (Ranatra fusea.) Can. Ent., XXXIV, p. 213. (9 figures eggs.) Peytoureau, S. a. Remarques sur I'organisation et 1' anatomie comparee des derniers segments du corps des Lepidopteres, Coleopteres et Hemipteres. Revue biol. Nord. France, VII, pp. 41-72. {Velia curTens structure male abd.) Pierre, 1903. Note sur les moeurs d' Elasmostethiis griseus Linn. Bull. Soc. Ent. Fr., 1903, pp. 131-132. (Guarding eggs and young, nothing new.) Plateau, Felex, 1884. Researches experimentales sur les Movements respiratories des insectes. Mem. Acad. Sc. Lettres Beaux, arts. Belg., XLV, p. 1-219. PoRTiER, P. Recherches physiologuques sur les insectes aquatiques. Ar- chives Zoologie Experimentale et Generale, Paris, 73, VIII, pp. 89-379. V PouLTON, E. B., 1906. Predaceous Insects and Their Prey. London. Trans. Ento. Soc, 1906, pp. 403-408. {N. glauca preying on Donacia vulgaris.) Provancher, L'abbe L., 1886. Petite Faune Entomologique du Canada, vol. Ill, (Hemipteres.) (Water bugs, p. 187-203.) PUTON, 1882. Pluie de Corisa {assimilis Fieb. in Turkestan.) Revue d'entom, I, p. 22. Rathke, H., 1861. Studien zur Entwicklungs geschichte der Insekten. Ent. Zeit. Stetten, 1861, p. 169. (See for Notes on Hydrometra laciistris and Naucoria cimicoides, the latter probably a Corixid.) "^ Redfern, p., 1859. On the method of production of sound by a species of Notonecta. Rept. of the 29th meeting of the British Ass'n. for Adv. Science. Trans., p. 173. (Rubbed front legs together.) Regembart, M., 1875. Observations sur la ponte du Dytiscus marginalis et de Quelques autres Insectes Aquatique in. Ann. Soc. Ent. Fr. (5), V, pp. 204-220. (Eggs of N. glauca in stems.) Reuter, O. M., 1888. Nagra ord om Hydrometri-dernas ofoevintring. Ent. Med., pp. 123-124. Reuter, O. M., 1910. Neue Beitrage zur Phylogenie der Heteropteren Familien. Acta Soc. Scient. Fenn., XXXVII, pp. 2-172. (Helsing- fors.) Richardson, N. M., 1907. The migration of Aquatic Hemiptera. Ent. Month. Mag., XLIII, pp. 105-107. (Flight of Corixa.) Riley, C. V., 1892. Directions for collecting and preserving insects. Bui. U. S. Nat. Hist., 39, Part F. Riley, C. V. and Howard, L. O., 1893. An Interesting Water Bug, {Rheumatobates rileyi.) Insect Life, V. pp. 189-1894. (See Insect hungerford: aquatic hemiptera. 263 Life, IV, p. 189, for plate of figures on this bug. In vol. V are figures of male larvse and adult sexes. Notes by Heidemann on be- havior are given.) Riley, C. V., 1895. Notes upon Belostoma and Benacus. Proc. Ent. Soc. Wash. Ill, No. 2, Nov. 2, 1893, issued 1895, pp. 83-88. Figs. 4 and 5. (Proves generic differences are not sexual.) ^ Robertson, James, 1895. The Stridulation of Corixa. The Irish Natu- ralist, IV, p. 319. (See also III, p. 114.) ROESEL, A. J., 1755. Insecten Belustigung. Part 3, 1755. ROGENHOFER, CoHxa hieroglyphise Duf. Verh. z. b. Wein, XXI, p. 65, (Gives notes on enormous swarms at Vienna and elsewhere.) ROSSIAS, Petrus, 1807. Fauna Etrusca Helmstadii, 1807, p. 352. RUDOW, Dr., 1915. Die Schmaratzen der wanzenartigen insekten. Ent. Zeit. Frankfurt a. Main, XXIX, pp. 17-18. Sahlberg, J. Halobates, a larval description. Ent. M. M., VII, p. 303. (Places it between Hydroessa and Velia.) Savigny, Jules C^sar, 1816. Memoires sur les animaux sans vertebres. Paris, 2 vol. Say, Thomas, 1859. American Ento., I, p. 361-368. Schaefer, T. W., 1895. The poisonous sting of the Electric Light Bug or "Belostoma," as it is called by entomologists. Kansas City Nr., LXX, No. 8, p. 3. (Cannot locate this.) , Schmidt, 1895. (For the manner in which males participate with the female during oviposition, see S. B. Ges. naturf. Berlin, 1895, pp. 38- 44. (Summary in Ent. Nachr., XXI, p. 206.) Schmidt Schwedt, E., 1891. In Zacharias Tier und Pflanzenwelt des Susswassers. SCHUMMEL, T. E., 1833. Beitrage zur entomologie, II. (Breslau.) Scott, J. Mesovelia furcata Muls. in the south of England. Ent. M. M., XII, p. 79. Severin and Severin, 1910. Notonecta undulata Say. Preying upon the eggs of Belostoma flumineuvi Say. Can. Ent., XLII, p. ^40. Severin, H. H. P. and Severin, H. C, 1911. Exp. Study on Death Feign- ing of Belostoma flumineum and Nepa apiculata. Behavior mono- graphs. Boston. Mass. Vol. I, No. 3; p. 47. (See Jr. N. Y. Ento. Soc, XIX, pp. 99-108.) Sharp, J., 1890. On the structure of the terminal segment in some male Hemiptera. Trans, entom. Soc. London, 1890. (Descript. of male characters of Pentatomids.) Shelford, V. E., 1913. Animal Communities in Temperate America. Shepherd, Forest, 1847. On the Habits of N glauca. Silliman's Amer. Journal (2) 4, pp. 423-424. Also Ann. and Mag. Nat. Hist. (2), I, p. 158, 1848. Simpson, S. G., 1848. Quoted by Dr. Spence in Trans. Ent. Soc, London, V, Proc. p. 36. (Flight of N. glauca in upper Miss. Valley, 25 miles long. Slater, Florence Wells, 1899. The Egg Carrying Habit of Zaitha. Am. Nat., XXXIII, pp. 931-933. (Female places eggs upon the male; does not mention Schmidt.) Slosson, a. T., 1908. A Hunt for Saldoida Osb. Ent. News, XIX, pp. 424-428. Soar, C. D., 1909. Larval Mites on Aquatic Animals. Am. Monthl. Micro. Journal, XXII, pp. 323-324. Stavely, E. F., 1871. British Insects. (A text book with colored plates. See pp. 316-328.) 264 THE UNIVERSITY SCIENCE BULLETIN. Stokes, A. C, 1893. The structure of insect tracheae with special refer- ence to those of Zaitha fluminea. Science, XXII, p. 44. Summers, H. E., 1891. The True Bugs of Tennessee. Bull. Tenn. Agri. Exp. Sta., IV, No. 3, pp. 75-96. SwAMMERDAM, JoHN, 1737. Biblia Naturae Leyde. (See, also below.) SWAMMERDAM, JoHN, 1758. The Book of Nature or the History of In- sects. Hill's English Translation. SwiNTON, 1877. On Stridulation in the Hemiptera Heteroptera. Ent. M. ^ Mag., XIV, pp. 29-31. Taschenberg, Dr. E. L., 1879. Einfuhrung in die Insekten Kunde Bremen. (See page 209.) TiGNY, F. M. G. T. de, 1802. Histoire naturelle des insectes composee d'apres Reaumer, Geoffray, De Geer, Roesel, Linne, Fabricus, ridigee suivant la methode d' Oliver. Paris, 1802, IV. Todd, J. E., 1883. A small Belostoma captures a fish. Amer. Nat., XVII, p. 548. Turner, H., 1879. The Belostoma piscivorus. Am. Nat., XIII, pp. 585, 710-711. ^Uhler, p. R., 1884. In Kingsley Standard Natural History, Vol II, pp. 249-276. (Splendid for water bugs.) Uhler, p. R., 1886. Check list of Hemiptera Heteroptera of N. A. Brooklyn Ento. Soc, 1886. Ulmer, George, 1911. Unsere Wasserinsekten. (Leipzig.) Van Duzee, E. P., 1907. Notes on Jamaican Hemiptera. Bull. Soc. Nat. Sci. (Buffalo), VIII, No. 5, pp. 1-79. (Eggs and larva of Micro- velia pulchella West.) Van Duzee, E. P., 1916. Check list of the Hemiptera of America North of Mexico. N. Y. Ento. Soc, N. Y. Van Duzee, E. P., 1917. Catalogue of the Hemiptera of America North of Mexico. Univ. of California Press. Berkeley. Verhoef, C, 1893. Vergleichende Untersuchungen iiber die abdomenal segmente der weiblichen Hemiptera Heteroptera und Homoptera. Verh. naturh Ver Rheinl. Westf. Auch. Diss. Bonn. ■/ Verrall, G. H., 1906. The anterior and posterior legs of insects. En- tom. Record, XIII, No. 6, pp. 184, 185. Walchenaer, C. a., 1802. Faune parisienne Insectes, ou histoire Ab- gegee des Insectes des environs de Paris. Paris. See pp. 331-350. Ward, Henry B. and Whipple, George C, 1918. Fresh Water Biology. Wiley & Sons, 1918. Weed, Clarence, 1889. Studies in Pond Life in Bull, of the Ohio Agri. Exp. Sta. Tech. Series, Vol. I, No. 1, Oct. 1889. (One of the first studies of pond life in America. Includes feeding habits of Zaitha fiximinea and Notonecta unclulata and describes eggs of the giant water bugs. Weed, Clarence Moors, 1897. Life Histories of American Insects. Macmillan Co., 1897. (A Family of Water Kings, Ch. I, account of Benacus, etc.) Weed, Clarence, 1888. Zaitha oviposition. Borner. Soc. Ent., Ill p. 34. Wefelscheid, H., 1912. Uber die Biologie and Anatamie von Plea. Zool. Jahrb. (Jena), XXXII, pp. 387-474. Weiss, Harry B.. 1914. Notes on the Positive Hydi-otopism of Gerris marginatus Say and Dineutes assimilis Aube. Can. Ent., XLVI, No. 1, p. 33. (Lost bearings at 30 yards from water.) Welch, P. S., 1912. Insect Life of Pond and Stream. Nature Study Rev., VIII, pp. 139-144, 221-225. hungerford: aquatic hemiptera. 265 Wesenberg-Lund C, 1910-1911. Ueber die Respirationsverhaltnisse bei unter dem Else iiber winternden Luft atmenden Wasserinsekten, bes. der Wasserkafer und Wasserwanzen. Iiiternat. Rev. ges. Hydro- biol., III. Wesenberg-Lund, C, 1913. Fortpftanzungsverhatnisse. Paaring und Eiablage der suss wasserinsekten Fortschritte der Naturwissen schaftlichen Forschung, VIII, pp. 161-286. Wesenberg-Lund C, 1915. Insektlivet i ferscke Vande-Kobenhavn Cyl- dendal, XVIII + 528, 377 fig. (Fresh water insect life. Have not been able to get this.) Westwood, 1871. Corixa ovivora. Proc. Ent. Soc. London, IV. (Cor- ixid from Thomas with notes on eating fish eggs.) Wheeler, W. M., 1890. New Glands in the Hemipterous Embryo. Am. Nat., Feb. White, F. Buchanan, 1873. Notes on Corixa, Ent. Mo. Mag., X, pp. 60-63, 75-80. (Taxonomic and life history notes. Fine behavior notes.) White, Buchanan, 1883. Voy. of Chall. XIX. Whittaker, Osc , 1903. Aquatic Rhynchota about Bolton. Entom. Rec, XV, pp. 23-24. (Water bugs in winter.) Whittaker, O., 1910. Pairing of N. glauca. See Ento., XLIII, p. 97. (Mating in January.) WiCKHAM, H. F., 1894. On the Habits of Some Oceanic Hemiptera, Ent. News., V, pp. 33-36. (Gives progression and drowning of H. wuller- storffi, and mating of Rhagovelia coUaris. Witlaczil, 1886. Weinent. Zeitg. V, p. 233. 1887 Zool. Auz X, p. 338. WiLKE, Gottfried, 1908. Einiges iiber die Biologic und anatomie der Wasserliiufer. (Hydrometra.) Wochenschr, XXIII, pp. 209-213, 11 fig. WiLMOTT, C, 1889. R. linearis. Habits and Transformations. Sci. Goss., XV, p. 252. Wood, F. (For a note on Nepa cinera Linn, burying itself in mud, see Ent. M. M., XXI, p. 201.) ERRATA. In the survey of families of Hemiptera place the "Fulgoridae" with the "Auchenorhjmcha." Page 19, line 19. "Rawlins" instead of "Rawline." Page 30, line 10. "Gerridie" instead of "Veliidse" (above Genus Halobates). Page 108, line 30. Insert "G. remiges" after the statement follow- ing C. Page 121, line 46. "Obsolete" instead of "obselete." Page 127, line 1. "Microvelia marginata, Uhl." Page 142, line 15. "Belostomatidae." Page 157, line 37. "Is" instead of "are." Page 173, line 21. "Genus Buenoa, Kirkaldy." Page 181, line 7. "Genitalia." Page 243, line 37. "Color Plate I" instead of "Plate XXX." Page 244, line 6. "Color Plate I" instead of "Plate XXX." Description of Plates. (267) PLATE I. KANSAS PONDS. Photo I. Smith Pond, a muddy pasture pond, frequented by cattle. Here Biienoa was dominant in midsummer. Photo. II. The large barren Brick Plant Pool, clay bottom and clay sides, no vegetation and few insects. Photo. III. Rock Pool, a small temporary pool in which Notonecta undulata is dominant in early spring. They show as black specks upon the water in the photograph. Photo. IV. Another view of Brick Plant Pool. Photo. V. Bismarck Grove Pond, a permanent pond, suitable for winter quarters, but containing too little vegetation for many aquatic bugs. A few Belostoma were taken here. Photo. VI. A small pond at brick plant. This pond is overgrown with willows and cottonwoods. The bottom is thickly strewn with leaves and brush, ideal winter quarters for many bugs. Photo. VII. Cattail Pool from the west end. This end is invaded by cattail. The water here is six inches to a foot deep. Photo. VIII. Cattail Pool from the south. The invading cattail on left. Here is the home of Hydrometra. Upon the floating Spirogyra are found Hydrometra, Microvelia horealis and Mesovelia midsanti in great numbers. Gerris marginahis is here and there upon the surface. This temporary pool lies in a rock quarry and dries up in midsummer. (268) PLATE I. •If. ' -:-, -\ .,/^-1^ji •I" 1 3" (269) PLATE II. Upper picture shows the Smoky Hill river valley in Wallace county, Kansas. The lower photo is a close view of the Smoky Hill river in its sandy bed (Wallace county). The stream is "up" somewhat. (270) PLATE II. ■tfntlji «C ^'^ %. •»-i // i H -^ (271) PLATE III. Fig. 1. Side view of Corixid clinging by his long middle legs to a grass stem in the water. (This and the other pictures on this plate were photographed from life.) f Fig. 2. Corixid clinging to a vertical support in the water. Fig. 3. Corixids in water on horizontal support. Fig 4. Belostoma fiumiuea feeding upon dragon fly nymph. Fig. 5. Characteristic position of Belostoma linminea upon a support in the water, awaiting the approach of prey. (272) PLATE III. (273) PLATE IV. Tab. XIII. Back-swimmers: adults and nymphs. Tab XV. Nepa. Tab. XVI. Ranatra. Tab. XIV. Naucorid. The above are photographs of the plates in Frisch, an old text published in 1727. Among the first published illus- trations of water bugs. (Not the first, however.) Photo. 1. The toad bug resting upon sand. Photo. 2. Vential view of female Corixid. Note the peculiar beak and remarkable differentiation of the limbs. Photo. 3. Notonecta undulata. Say. Photo 4. Bucnoa margareiacea. Bueno. Photo. 5. Female Corixid — Ramphocorixa acuminata. Uhl. (274) PLATE IV. TiblKl: (275) PLATE V. Photo, l. Ventral view of a toad bug', Gelastocoris sp. new, showing him in possession of three lace bugs (Tingididae) . (Bug from Larned, Kan.) Photo. 2. Ventral view of another bug of the same species with a Mirid (Capsid). Photo. 3. The marshtreader, Hydrometra martini, from the Cat- tail Pool at Lawrence, Kan. Photo. 4. The end of a battle — photograph of Ncpa and Ranatra. These bugs were placed in a jar of water without supports and Nena proved to be the better able to control himself. (Ithaca, N. Y.) Photo. 5. Photograph of Salda anthracina from the lx)g pond. Ring- wood Hollow, near Ithaca, N. Y. (276) PLATE V. #;^v^v X 1 (277) PLATE VI. Fig. 1. Eggs of Salda aiitliracina in bog moss. Fig. 2. Photograph of egg of Hyd)-o»ictia )iia)i'.ni. Fig. 3. Eggs of Lamprocanthia crassicornis at the base of sho/e grass. Fig. 4. Microphotograph of the egg of Hydromeira attached to a sprout of cattail. Two sprouted seeds of cattail are shown. Note the superficial resemblance. Fig. 5. Gerris eggs laid in nature on the underside of grass blade floating out upon the water. On the upper grass blade the eggs have hatched. Note the longitudinal rent. Fig. 6. Eggs of Gerris marginatiis on upper surface of leaf blade in an aquarium containing very little water. (278) PLATE VI. MHIIIilM^HIltl (279) 1 PLATE VII. EGGS OF RANATRA. I. Photograph of Ranatra eggs in cattail leaf. The lower part of the leaf has been removed to show the eggs. II. Photograph of cattail leaf containing egos of Ranatru. III. Clo.-e view of the one shown in I. (280) PLATE VII. 1 (281) PLATE VIII. Eggs of Notcnecta ir)-o)-ata inserted in the stem of money- Egg of Notonecta undulata on edge of cattail leaf. Eggs of Notonecta insulata on Cham. Eggs of two species of Notonecta N iiisiilata above, N. variabilis below. Photo. 5. Corixid eggs on a submerged twig. They are often much more abundant than this. The twig here photographed was a part of a six-foot branch covered throughout. The twig is a fair sample. Photo. 6. Egg of Corixid enlarged. Photo. 1. wort. Photo. 2. Photo. 3. Photo. 4. (282) PLATE VIII. (283) PLATE IX. GELASTOCORID AND NAUCORIU. Fig. 1. Ventral view of Gehistocoris, female. Fig. 2. Antenna of Saldid. Note the extra intersegrnents. Fig. 3. Egg of Gehistocoris sp. yieiv. Fig. 4. A bit of chorion of the egg shown in tigure 3. Fig. 5. Ventral view of female ovipositor of Gelastocoris Fig. fi. Ventral view of abdomen of male Gelastocoris. Note asym- metry. Fig 7. Ventral view of ovipositor of Pelocoris corolinensis. Fig. 8. Ventral view of abdomen of female Pelocoris carolinensis. Fig. 9. Ventral view of abdomen of male Pelocoris carolinensis. (284) PLATE IX. (285) PLATE X. Fig. 1. Hebriis concinnus, ventral view of male abdomen. Fig. 2. Hebms egg partially dissected from bit of moss. Egg shows the red eye spots of embryo within. Fig. 3. Hebms, ventral view of abdomen of female. (Drawings 1, 2, 3, made to same scale. Note the relatively large size of the egg. Fig. 4. Hebms eggs in loose leaved moss, showing attempt to conceal by fastening the tip of one leaf to the one above it, with some gelatinous material. Fig. 5. Hebrus egg freshly laid, surrounded by the hyaline tissue of a moss leaf. Fig. 6. Lamprocanthia crassicornis, egg in situ between the leaves of moss. Fig. 7. Scvlda anthracina egg, same scale as figures 6 and 7. Fig. 8. Hebrus egg in situ between the leaf and stem of close grow- ing moss. Fig. 9. Lamprocanthia crassicornis, ventral view of abdomen of male. Fig. 10. Clump of sedges showing eggs of L. crassicornis in situ. Fig. 11. L. crassicornis egg. Compare with figure 7. Fig. 12. L. crassicornis, ventral view of abdomen of female. (286) PLATE X. H G Hoiso'^'-i- "/«/ (287) PLATE XI. HEBRUS AND RHAGOVELIA. Fig. 1. Adult female Hebims concinnus. Fig. 2. Antennae of Hehrus to show the five segmented condition plus the small segments. Fig. 3. First Instar nymph of Hehrus. Fig. 4. Fore and hind wings of Hehrus. Fig 5. Female Rhagovelia ohesa. Figs. 6 and 7. Tarsus of middle leg to show the cleft condition with its tuft of fringed hairs. These spread beneath the surface of the water, as in 7, and aid in rowing over rapid water. Fig. 8. One of the fringed hairs enlarged. (6, 7 and 8 from Bueno.) Fig. 9. Male Rhagovelia ohesa. (288) PLATE XL PW'' 4 ..^ / -•^2:= (289) 19 — Sci. Bui. — 1669 PLATE XII. MICROVELIA BOREALIS. 1. A single egg in its mass of adhesive material. 2. First instar nymph. 3. Second instar nymph. 4. Third instar nymph. 5. Adult apterous female. 6. Molted skin of third instar nymph. 7. Adult apterous male. 8. Last instar nymph. 9. Adult male winged. (Determined by Bueno, but does not show curved hind tibia.) 10. An egg shortly before hatching. The embryo usually lies with its dorsal surface to the support. The hatching device shows between the eyes. 11. Female winged. (290) PLATE XII. 'i« ■••■igj^.iY PLATE XIII. HYDROMETRA MARTINI. Fig. 1. Second instar nymph. Fig. 2. Third instar nymph. Fig. 3. Fourth instar nymph. Fig. 4. Fifth instar nymph. Fig. 5. First instar nymph. Fig. 6. Egg of Hydrometra martini. Fig 7. Hatching Hydrometra. H., hatching device on post-natal molt; a, coiled stylets; c, labrum; h, beak; d, antenna; e, legs. Fig. 8. Ventral view of abdomen of male Hydrovietra martini Fig. 9. Side view^ of same. Fig. 10. Hatching Hydrometra. Note the hatching device between the eyes. Fig. 11. Foot of Hydrometra. Fig. 12. Side view above. Dorsal view below of Hydrometra australis. Fig. 13. The same for H. martini, after Bueno. Fig. 14. Female Hydrometra, ventral view. Fig. 15. Ventral view of female abdomen. Cleared in cedar oil. Shows egg. (292) PLATE XIII. (293) PLATE XIV. MESOVELIA MULSANTI. Fig. 1. Mesovelia mulsanti, winged male with membrane of wings broken off. Fig. 2. Mesovelia mulsanti, winged female, wings entire. Fig. 3. Fifth instar nymph; note the dorsal pore on fourth abdominal segment. Fig 4. First instar nymph. Fig 5. Eggs in stem of sedge, surface view of the two at left. The other two seen in situ in stem when portion of stem is removed. Fig 6. Fourth instar, apterous form. Fig. 7. Two eggs, showing their connection with surface of stem; eye spot shows in the one to the right. Fig. 8. The embryonic membrane, cast by the hatching nymph; 2 "pegs" shown at the left enlarged. Fig. 9. Apterous male. Fig. 10. Apterous female. Fig. 11. Male genitalia from above. Fig. 12. Male genitalia from side, hooks in black. Fig. 13. Ventral view of female ovipositor in its sheath. Fig. 14. Ovipositor lateral shafts shaded. They slide up and down on the central shaft. Fig 15. Cephalic view of ovipositor, turned into position for action. Plate first appeared in Psyche XXIV. (294) PLATE XIV. (295) PLATE XV. GERRIS AND TREPOBATES. Fig. 1. Hatched egg of Gertis marginatus, showing the postnatal molt and the black chitinous "egg burster." Fig. 2. First instar nymph of G. marginatus. Fig. 3. Nymphal molt of Gerris. Fig. 4. Front foot of Gerris Fig. 5. First instar nymph of G. remigis. Fig. 6. Ventral view of male Gerris. Fig. 7. Dorsal view of male Gerris. Fig 8. Ventral view of female Gerris. Fig. 9. Dorsal view of female Gerris. Fig. 10. Mating Gerris. Fig. 11. Eggs of Trej)obates pictus on under surface of floating duck- weed. (Lemna.) Fig. 12. First instar nymph Trepobates pictus. Fig 13. Egg ready to hatch. Note the "egg burster" between the eyes. The small spots are red as well as the eyes. Fig. 14. Eggs of Trepobates pictus on underside of leaf blade. Note the gelatinous matrix. If disturbed the entire mass comes from the leaf intact. (296) PLATE XV. (297) PLATE XVI. RHEUMATOBATES RILEYI. Fig. 1. Ventral view of male. Note the peculiar formation of an- tennae and hind femora. Fig. 2. Antennae of female. •Fig. 3. Fore leg of Rheumatobates, inner view. Fig. 4. Dorsal view of tip of abdomen of female, dorsal abdominal wall removed to expose the base of the ovipositor. Fig. 5. The ovipositing device partly dissected. Figs. 6 and 7. Left side view of one of the drill parts. In Figures 4 to 7 the same letters are used to designate like parts. o. Dorsal abdominal plate. b. Ventral broad flat valve employed as sheath to the drill parts. c. The drill parts, flattened chitinous structures grooved to slide within d. d. Upper part of ovipositor parts. The heavily chitinized braces are shown at e. e. The chitinous braces of the dorsal pair of ovipositor parts. The ovipositor is made up of three pairs of shafts, a ventral broad flat pair serving as shields (b) . These are attached at their upper end to (c), the drilling parts which are strongly chitinized thin plates grooved to slide within (d) . Between the dorsal valves (d) is a membrane which forms the dorsal wall of the egg tube. This is attached to (i) . Fig. 8. Dorsal view of abdomen of female showing ova. There were eight well-developed ova. Fig. 9. Egg of Rheumatobates rileyi. (298) PLATE XVI. (299) PLATE XVIL BELOSTOMA. Fig. 1. First instar B. fluminea. Fig. 2. Second instar, B. fluminea. Fig. 3. Third instar, B. fluminea. Fig. 4. Fourth instar, B. fl^iminea. Fig. 5. Egg of B. fluminea. Fig. 6. Egg hatching. Note the red eye spots appearing. The thin margins of the nymph are rolled ventrally. Fig. 7. Fifth instar B. fluminea. Fig. 8. Front tarsus of first instar of B. fluminea. Note the size of the claws. Compare with figure 9. Fig. 9. Front tarsus of second instar of B. fluminea. The second claw diminishes in size till in the adult it is not present. Fig. 10. Antenna of first instar nymph B. fluminea. Fig. 11. Antenna of fifth instar nymph B. fluminea. Fig. 12. Ventral view of abdomen of female B. fliiminea. Fig. 13. Egg of Lethocerus Uhleri laid in laboratory. Fig. 14. Ventral view of abdomen of male B. fluminea. Fig. 15. Ventral abdominal view of Benacus griseus, female. Fig. 16. Single eggs of Benacus. Fig. 17. Ventral abdominal view of Benacus griseiis, male. (300) PLATE XVII. (301) PLATE XVIII. RANATRA AND NEPA. Fig. 1. Ventral view of the tip of abdomen of female Ranatra. Note the narrow carinated ventral plate. Fig. 2. Ventral view of tip of abdomen of male Ranatra. Note broad ventral plate. Fig. 3. Enlarged egg of Ranatra. Note micropylar area near the base of the filaments. Fig 4. Ventral view of head and prothorax of Ranatra to show tonal device. (See, also, figure 9.) The inner margin of the prothoracic shoulders (b) is roughened by a series of tiny ridges over which a roughened patch (a) on the outside of the coxa rubs. Fig. 5. Fore leg of Ranatra. Fig. 6. The cephalic end of a Ranatra egg, showing the post-natal molt and the rent in the egg shell through which the nymph emerged. Fig. 7. Fore leg of Nepa. Fig. 8. Cephalic end of Ranatra egg, side view. Note the micro- pyle (m). Fig. 9. Tonal device of Ranatra, (c) coxa outside view, with rougened patch (a). Shoulder of prothorax with rasp (?•) along its inner mar- gin. (See figure 4.) Fig. 10. Hydrachnid larva attached to caudal filament of Ranatra, thus making the tube nonfunctional to this point. Fig. 11. Ventral view of abdominal tip of female Nepa. Fig. 12. Egg of Nepa apicidata. Note that there are eleven filaments in our species. The European form has long been described as possess- ing seven. Fig. 13. Ventral view of abdominal tip of male Nepa. Compare with figure 11. (302) PLATE XVIII. A 1 1 ^ \| $~ \ \ ^ \ \ \" 1 4 ■ (303) PLATE XIX. NOTONECTA NYMPHS. Fig. 1. Dorsal view of Notonecta variabilis first instar nymph. Fig. 2. Dorsal view of Notonecta irrorata first instar nymph. Fig. 3. Dorsal view of Notonecta insulata first instar nymph. Fig. 4. Egg- of N. insulata. Fig. 5. Hind femur of first instar nymph of Notonecta variabilis. Fig. 6. Egg of N. irrorata. Fig. 7. Hind femur of first instar nymph of Notonecta insulata. Com- pare with fi.gure 5. Fig. 8. Egg of N. variabilis. Fig. 9. Middle femur (ventral view) of N. irrorata first instar nymph. Fig. 10. Egg of N. undulata. Figures 4, 6, 8 and 10 to same scale. Fig. 11. Middle femur (ventral view) of N. variabilis. Compare with figure 9. Fig. 12. Eggs of Buenoa margaritacea inserted in stem. Fig. 13. Hind leg of first instar nymph of N. variabilis. Note the banded leg. (304) PLATE XIX. (305) 20 — Sci. Bui. — 1669 PLATE XX. Fig 1. Ventral view of terminal abdominal segments of male No- tonecta nndnlata Say. Fig. 2. Fifth instar nymph. Fig. 3. Ventral view of terminal abdominal segments of female. Figs. 4a to Ae. Diagrams of dorsal view of meso- and metathorax of nymphs, first to fifth instars, respectively, showing the developing wing^ pads. Third instar nymph. Both rows of swimming hairs shown. ' Antennae of fifth instar nymph. Antennae of adult male. Second instar feeding upon an ostracod. First instar nymph, drawn by Miss Ellen Edmonson. Tar&us of hind leg of first instar nymph, showing the tarsal claws, which become less conspicuous as development advances. Fig. 11. Egg of Notonecta undidata, showing details of structure, drawn by Miss Ellen Edmonson. Plate first used in Ento. News, XXVIII. (306) Fig. 5. Fig. 6. Fig. 7. Fig. 8. Fig. 9. Fig. 10 PLATE XX. >y. e.-«"iet.»fii«<(. J.(. (307) PLATE XXI. Fig. 1. Two eggs of Notonecta undulata after hatching, showing the characteristic slit in the shell and the clear embryonic membrance shed by the nymph upon emerging. Fig. 2. Adult Notonecta undulata in the water. Fig. 3. Egg nearly ready to hatch. Note the red eye spot and the dark line at margin of the gelatinous substance which glues the egg to its support. Fig. 4. A freshly laid egg viewed from above. Fig. 5. A roadside pool in early spring. The back-swimmers were arriving in numbers, flying from some unknown quarters where they had passed the winter. Fig. 6. Eggs of Notonecta undulata, freshly laid upon old weed stems lodged in the waters of the pool. Gyrinid beetles lay somewhat similar eggs, which may be distinguished by their arrangement upon their sup- port and by the fact that the eye spots in advanced eggs are black instead of red, and farther from the end of the egg than in those of the back-swimmers. Plate first used in Ento. News, XXVIII. (308) PLATE XXI. ^1, ^t|, (309) PLATE XXII. NOTONECTA IRBORATA. Fig. 1. Ventral view of the genitalia of the female N. irrorata, showing the drilling parts of the ovipositor, indicated by V. It is one of these parts that is figured from three aspects in plate XXIII, figure 9. Fig. 2. A portion of water-soaked cattail leaf showing two eggs of N. irrorata deposited through one puncture. Fig. 3. Egg of N. irrorata in moneywort stem. The embryos usually develop with cephalic end at micropylar pole of the egg. This one is reversed, as shown by the eye spot of the developing nymph within. Fig 4. Egg in moneywort, showing the nature of the rent through which the nymph escaped. Postnatal molt removed. Fig. 5. Ventral view of the genitalia of the female N. insulata, show- ing the drilling parts of the ovipositor, indicated by V. It is one of these parts that is figured from three aspects in plate XXIII, figure 5. This plate appeared in Ento. News, XXIV. (310) PLATE XXII. (311) PLATE XXIII. OVIPOSITOR OF NOTONECTjE. This plate contains three views of the left member of the first pair of gonapophyses of the fem.ale of each of the species of the genus Noto- necta available in this country. Two species have been omitted because of the lack of material. The views ai-e from left to right, outside or lateral view; ventral view showing the organ on edge, inner view. All of the drawings were made with camera lucida and drawn to the same scale. The length of the adult, together with outside measurements of the ovipositor, are added for purposes of comparison of relative size of parts. The writer believes that a study of these organs should be taken into account in determining rela- tionship of species. A study of a wide series would certainly establish the range of variability in size and shape of these parts, and in some cases, if not all, aid in specific determinations. The drawings here pre- sented are, however, intended to indicate merely the correlation of this organ with the habit of oviposition. Fig. 1. Notonecta lutea. Size of adult, 13-17.1 mm ; valve of ovi- positor, 1.625 mm. x .725 mm. Specimen loaned by Mr. Gibson, of Nat. Mus. Taken in Finland by Sahlberg and determined by Kirkaldy. Fig. 2. Notonecta raleighii. Size of adult, 9 mm.; valve of ovipositor, .4 mm. X ,25 mm. Specimen given to me by Mr. J. R. de la Torre Bueno. Fig. 3. Notonecta undulata. Size of adult, 10-13 mm.; valve of ovi- positor, .5 mm. X .312 mm. Material from Ithaca, N. Y., and Lawrence, Kan. Fig. 4. Notonecta variabilis. Size of adult, 8.2-10.2 mm.; valve of ovi- positor, .4 X .312 mm. Fig. 5. Notonecta insulata. Size of adult, 12.6-15.5 mm.; valve of ovipositor, .7 x .425 mm. Material from Palo Alto, Cal. Fig. 6. Notonecta glauca. Size of adult, ?; valve of ovipositor, 1.125 x .55 mm. Loaned from Nat. Museum by Mr. Gibson ; a specimen from England, collected by Uhler. Fig. 7. Notonecta Mexicana. Size of adult, 11-14 mm.; valve of ovi- positor, .7 X .5 mm. Specimens from Arizona. Fig 8. Notonecta shooterii. Size of adult, 8-13 mm.; valve of ovi- positor, .65 X .375 mm. Specimen given to me by Mr. J. R. de la Torre Bueno. Fig. 9. Notonecta irrorata. Size of adult, 11.8-14.4 mm.; valve of ovipositor, 1.675 x .575 mm. Material taken at Ithaca, N. Y. Fig. 10. Notonecta uhleri. Size of adult, 12 mm. ; valve of ovipositor, .65 X .35 mm. Specimen given to me by Mr. de la Torre Bueno. Fig. 11. Notonecta indica. Size of adult, 10.5 mm.; valve of oviposi- tor, .5 X .375 mm. Material from Douglas, Ariz., collected by Doctor Snow. Plate first used in Ento. News, XXVI. (312) PLATE XXIII. H.6Hun6e/iFe/td. - Jel (313) PLATE XXIV. BUENOA MARGARITACEA, All the figures refer to Buenoa margaritacea unless otherwise stated. Fig. 1. Egg removed from the stem, showing the clear exposed area of the egg and its margin of white. Fig. 2. Eggs "in situ" in stem of Juncus. Fig. 3. A portion of the stem of Juncus removed to the egg in situ. Fig. 4. Ventral view of the female, showing the appearance of the ovipositor and the crib formed by the two anterior pairs of legs for the retention of entomostracans. Compare with figure 10. Fig. 5. Inner view of the stridular areas on the femur and tibia of the anterior leg of the male, greatly enlarged from figure 6. Fig. 6. Inner view of the anterior leg of male, showing the tibial prominence and stridular areas. Fig. 7. Eggs of Notonecta undulata glued to the stem of aquatic plant. Drawn from a photograph. Plate from Ento. News, XXVIII. (314) PLATE XXIV. //.flWuncEBFoBd i^l. (315) PLATE XXV. PLEA STRIOLA. Fig. 1. A sprig of water weed (Elodea) with the inserted eggs of Plea. An adult drawn to same scale as eggs shown. Fig. 2. Adult female Plea, with her ovipositor exserted. - Fig. 3. Egg of Plea, same scale as figure 2. Fig. 4. Side view of body of Plea, hemelytra removed showing the wing-pad. Some have the flying wings much better developed than this specimen. Fig. 5. Egg of Plea inserted in plant tissue. Fig. 6. Egg of Plea. Fig. 7. Ventral view of male abdomen of Plea. Fig. 8. The edge of the right hemelytron shown in figure 9. Note the white ridge with its irregularities that snap into irregularities of the open hemelytron, making a firm union of the two. This has led writers to state that the hemelytra of our Plea are soldered into one piece. Fig. 9. Hemelytra of Plea, showing suture clasping device. Fig. 10. Vential view of female abdomen of Plea striola. (316) PLATE XXV. (317) PLATE XXVI. ARCTOCORIXA ALTERNATA. — Kansas Material. Fig. 1. Egg of the Corixid species here considered. Fig. 2. Adult Corixid, Arctocorixa alternata. Fig 3. Egg of a smaller species. Fig. 4. First instar nymph. Fig. 5. Second instar nymph. Fig. 6. Tarsus and claws of hind leg of first instar. Fig. 7. Third instar. Note the fringe of black hairs on the wing-pads. Fig. 8. Egg shell after hatching, showing the characteristic rupturing of the egg for the egress of the nymph. Fig. 9. Fourth instar nymph. Fig. 10. Front leg of late fifth instar nymph, showing the tibia and tarsus of the adult within the terminal nymphal segment. Fig. 11. Fifth instar nymph. Fig. 12. The foreleg of the adult male. Fig 13. Ventral view of abdomen of female. Fig. 14. Antenna of third instar nymph. Fig. 15. Antenna of late fifth instar, showing the three distal seg- ments of the adult in the terminal nymphal segment. Fig. 16. Antenna of adult. Fig. 17. Ventral view of abdomen of male, showing the peculiar arctoco asymmetry of the segments. Plate appeared in Jr. N. Y. Ento. Soc, XXV. (318) PLATE XXVI. (319) PLATE XXVII. Fig. 1. Fifth instai" of Palmacorixa buenoi. Fig. 2. Male PalmacoHxa buenoi from Beebe lake. Fig. 3. Male PahnacoHxa buenoi from Bool's Backwater, nearby. These sizes are distinct. Fig. 4. Fourth instar nymph of PalmacoHxa buenoi. Fig. 5. Third instar nymph of Palmacorixa buenoi. Fig. 6. Second instar nymph of Palmacorixa buenoi. Fig. 7. First instar nymph of Palmacorixa buenoi. Fig. 8. First instar nymph of Arctocorixa alternata. N. Y. variety. Fig. 9. Fourth instar nymph of Arctocorixa alternata. N. Y. variety. Fig. 10. Third instar nymph of Arctocorixa alternata. N. Y. variety. Fig. 11. Second instar nymph of Arctocorixa alternata. N. Y. variety. Fig. 12. Fifth instar nymph of ArctocoHxa alternata. N. Y. variety, Compare the various instars of the two bugs as to color pattern. (320) PLATE XXVII. (321) 21 — Sci. Bui. — 1669 4- PLATE XXVIl/. CORIXIDjE. Fig. 1. Crayfish bearing eggs of the Corixid Rampfiocorixa acumi- 7iata. The arrows show the direction of the water current. The writer believes this accounts for the presence of the first eggs of the Corixid on the first abdominal pleurites. Fig. 2. Head of male of Ramphocorixa acuminata from above. Fig. 3. Head of female of R. acuminata. Fig. 4. Pala of male of R. acuminata. Fig. 5. Antenna of 5th instar nymph of R. acuminata. Fig. 6. Digestive system of a Corixid to show the termination of the malpighian tubules against the rectal pouch. Fig. 7. Front leg of male Palmacorixa huenoa found in Beebe lake. It is a much larger bug than is found in Bool's Backwater, nearby. See plate XXIV. Fig. 8. Egg of Ramphocorixa acuminata. Fig. 9. Front leg of male Palmacorixa gillettei. Abbott. Copied from Abbott. Fig. 10. Front leg of Palmacorixa buenoi. Abbott, from Bool's Back- water. Fig. 11. Same as figure 10. Note the variation. Fig. 12. The hatching of a Corixid. First a bubble appears after the egg bursts, then the nymph slowly fills the bubble. This postnatal molt bursts when the nymph is two-thirds way out. It remains as a cast and crumpled garment as shown. Fig. 13. Male pala of Corixid: Fig. 14. Eggs of various species of Corixids. Fig. 15. Corixid egg. Showing how the egg enlarges as embryo de- velops within. (322) PLATE XXVIII. 1 (323) PLATE XXIX. Fig. 1. Cephalic view of head and forelegs of a female Corixid. The left leg has been turned in a position to show the nature of the paler sur- face, which in the right leg is appressed to the face. Fig. 2. The extremity of the beak of a Corixid from a specimen cleared in caustic potash. It shows two of the stylets and the nature of their tips. It also reveals the fact that they are strongly chitinized only for a short distance. They afford a remarkable contrast to the stylets of Hydrometra, which are exceedingly long and capable of being exserted be- yond the tip of the beak a distance nearly as great as the length of the beak itself. Fig. 3. The tip of a stylet of Hydrometra to show its equipment for retaining prey. These stylets when not exserted extend well back into the peculiarly long head of the bug. Hydrometra spears its prey, and de- pends upon the effectiveness of its barbed stylets to hold, and its poison- ous salivary injections to subdue, the victim. Fig. 4. A view of the pala of the right foreleg of a female boatman. An efficient device for scooping up and bringing to the mouth the sedi- mentary material in the deposits on the bottom of the pool. Fig. 5. Lateral view of the head and forelegs of a male Corixid, to illustrate the process of food gathering. The arrows indicate the direc- tion of the food material. The stylets are shown exserted, one foreleg passing food material across the face and over the buccal opening, the other in the act of gathering material. Fig. 6. The right foreleg of a Naucorid seen in ventral view. This presents the usual modification of the foreleg for grasping, and is shown in contrast to the type of the foreleg of the boatmen, so long believed to be predaceous. Plate used in Jr. N. Y. Ento. Soc. XXV. (324) PLATE XXIX. (325) PLATE XXX. CORIXID MOUTH PARTS AND DIGESTIVE TRACT. Fig. 1. The digestive tract of a Corixid, showing the long green fila- ment of algje which it had eaten. Sometimes the boatmen fill their stomachs with great skeins of Oscillatoria. (The above drawing was made from a permanent slide, the green color being preserved by fixation in 8% formalin plus copper acetate.) Fig. 2. The tip of the so-called rostrum of a large species of Corixid. The median stylets and one lateral stylet (in black) are shown project- ing from the small oral opening (o). This opening is bounded by the membrane (m), which is provided with the chitenous trusses (I). These trusses are attached to the muscles (mu). Thus when the muscles con- tract the oral opening is considerably enlarged. Note the projecting, somewhat spoon-shaped guards, below (g). When the palte of forelegs sweep downward across the face these concave shields help to keep the food from passing beyond its objective. Fig 3. Digestive system of a Corixid. The inner surface is increased by diameter instead of by length. There are four malpighian tubules. This drawing is from the mount of the digestive tract of a bug that had fed for a few minutes over some sediment lightly sprinkled with carmine grains. Quantities of carmine were swept in with the organic ooze. Fig. 4. Ventral enlarged view of mouth parts dissected. The man- dibular stylets are on the outside. Fig. 5. Dorsal or cephalic view of mouth parts. Fig. 6. Stylets enlarged. a. right inner stylet. h. left inner stylet. c. left outer stylet. (See, also, figure 5.) Fig. 7. Shows left inner or maxillary stylet (6) and right outer or mandibular stylet. (326) PLATE XXX. (327) ERRATA. The color plates are the work of the Bureau of Engraving, Inc., Minne- apolis, Minn. For some reason their mark was omitted from the face of the plates. Color plate II was not reduced as ordered, therefore the magnifica- tions are incorrect. Fig. 1. Magnification 4.5 instead of 3.50 Fig. 2. Magnification 5.0 instead of 3.90 Fig. 3. Magnification .9 instead of .70 Fig, 4. Magnification 4.5 instead of 3.50 Fig. 5. Magnification ,9 instead of .70 Fig. 6. Magnification .9 instead of .70 Fig. 7. Magnification 2.1 instead of 1.66 Fig. 8. Magnification 2.8 instead of 2.20 Fig. 9. Magnification 1.8 instead of 1.40 (328) The Male Genitalia as Characters of Specific Value in Certain Cryptocerata (Hemiptera-Heteroptera). The use of the male genitalia in specific determination has been employed for a long time in certain groups of insects. For the most part their use has been limited to those forms possessing readily accessible and perfectly apparent genital parts. It has been demonstrated in recent years, by Doctor Knight in the Miridae and Crawford in the Homoptera, that a close scrutiny of the male genitalia of forms superficially difficult to separate affords a solution to hitherto perplexing problems. The writer published a study of the "Oviposition of the Notonectse" in the Entomological News, vol. XXIX, 1918. This was in no way a systematic paper and had in mind the relation of form to function only. It was stated, however, that the gonapophyses appeared to be specifically distinct in size and shape and the suggestion was made that a study of the males might be worth while. It was the writer's good fortune to be carrying on research work in the same quarters in which Dr. Harry Knight was working over his Miridae. It was upon his advice that the writer undertook to discover specific characters in certain of the water bugs. This undertaking was in the face of some discouragements, for Kirkaldy wrote : "Great hopes were en- tertained by me that the male genitalia (of Notonecta) would furnish a reliable diagnostic character, but in the few species (N. glauca, N. lutea, N. irrorata, and N. undulata) of which suitable material was available, these hopes have not been realized." Furthermore, Mr. J. R. de la Torre Bueno ad- mitted, when the problem was suggested to him, that he had long had in mind such a study but that the species in the genus Notonecta are most confusing. The writer, however, had before him the necessity of solv- ing some questions of specific determination that had arisen in connection with his biological work in the Corixidae. From these researches came his determination to master the tax- (329) 330 THE UNIVERSITY SCIENCE BULLETIN. onomy of this family and to prepare a monograph of it, a work in which he has been engaged for some time. A searching examination of some of the related families has shown some of them to possess quite specifically distinct genital characters. The males of Gelastocoridse, Notonectidae and Corixidae have the genital claspers attached to a capsule- like segment which is capable of being withdrawn into the body and thus lies hidden. This strongly chitinized capsule is but loosely attached to the body wall and can therefore be drawn forth and removed from the bug in toto without the least injury or mutilation to the external features of the specimen. For these studies the specimen was first relaxed, then held under the binocular while the genital capsule was removed, an operation requiring considerable skill in some Corixidae. The capsule was then placed in a vial of caustic potash and left until sufficiently clear for study. The drawings submitted herewith were made with a camera- lucida and all drawn to the same scale. The suranal plate and intromittent organ have been omitted in the drawings for sake of clearness. This paper is preliminary in nature and intended only to call attention to the possibility of using the genitalia of the males of some of the aquatic and semi-aquatic Hemiptera, a line of characters not hitherto used, in their taxonomy. The genitalia of the Belostomatidae and Nepidae are not used in these studies because these families are under investigation by others. The genitalia of Corixidae are not figured, for the reason that a completed study of the family by the writer will appear later. The genital segment bearing the male claspers in the Saldid is exposed and the removal of more than the claspers them- selves would mutilate the specimen. The Naurcorids ex- amined carry a relatively smaller capsule with claspers that, while different in shape in the two or three species studied, are not so strikingly distinct as in some of the other forms. Of the three families having the genital capsule entirely hidden, the Notonectidae have the simplest device. The capsule of a member of the genus Notonecta is erect and bilaterally symmetrical. The claspers, right and left, are about alike. The shape of the capsule itself as well as that of the claspers afford characters of specific value — as is shown by a study of THE UNIVERSITY SCIENCE BULLETIN. 331 the drawings on plate XXXI. In the genus Buenoa we find the beginnings of asymmetrical development in that the right and left claspers are unlike. (A faint suggestion of this is to be found in Pelocoris and Plea.) See the drawings on plate XXXI, figures 1, 2 and 4. In the families Gelastocoridse and Corixidae are found marked asymmetry, not only of the genital capsule and its parts, but of the abdominal segments themselves as well. The claspers of Gelastocoris are profoundly unlike — the ventral one (the right one) is large, stout, and equipped with short, blunt pegs or processes ; the other one is small and not greatly modi- fied in shape. See plate XXXII, figure 5, R. C. and L. C. The Corixid capsule and its parts are more complicated and per- plexing than the forms above mentioned, but have been used by the writer with success as an aid to the separation of difficult species. There are figured, herewith, the male genital segments of nine species in the genus Notonecta* — two in Buenoa, one in Plea, two species of Amhrysus, two Saldids, and two Gelas- tocorids. The reading of the discussion which follows should be accompanied by an examination of plates XXXI and XXXII. * The figures of Not07iecta raleighi Bueno, Notonecta shootcri, Uhl., Notonerta vhleri Kirk., Notonecta montezuma Kirk., and Notonecta Ivtea Mull, are not figured. Notonecta lutea from British Columbia, identified as such by Bueno, has a genital bulb much like N. irrorata. The ventral process is shorter and located farther cephalad. The fold of the lobe in front of the clasper extends to the ventral margin. The.se two species, N. irrorata and the so-called lutea, are quite related. The genital bulb of Notonecta shooteri re- sembles figure five very closely, and the bulb of Notonecta raleighi is very like that of Notonecta variabilis. PLATE XXXI. Figs. 1 and 4. Buenoa margaritacea, Bueno. Left and right view of the male genital segment indicates the marked difference in the shape of the claspers. All the material in this genus examined shows a similar asymmetry. The bulb here figured was taken from a specimen identified by Mr. Bueno. L. C. := left clasper. R. C. =: right clasper. Fig. 2. Buenoa elegans (Fieb). The genital bulb of this species differs from its larger relative figured as above by the slight constriction as shown in the lateral profile of the lower margin. The left clasper has a larger basal lobe than the Buenoa mar- garitacea Bueno. Th& drawing is partly free hand, and the view is from the left side. The specimen from which this drawing was made was determined by Mr. Bueno. C. = clasper (left): Fig. 3. Plea striola (Fieb.). This tiny back swimmer has a genital segment somewhat like its larger relatives. The drawing is made from the left side and shows the muscular base of the penis. The claspers are curved, the right one is slightly more slender and longer than the left — 'just a suggestion of asymmetry. This drawing is made from ma- terial taken in New York. A study of Kansas material shows a slight difference. Bueno has stated that he believes there is more than one species in the United States, and a careful study of the material of the country may prove his contention. The material in the Snow collections bears Bueno's label. C. =r clasper (left). Fig. 5. Notonecta — sp? The male genital bulb from a specimen that came to me among some Corixids. It lacks collector and locality label so it is not possible to say from whence it came. D. C. = dorsal collar. L. C. =: left clasper. Fig. 6. Notonecta indica Linn. The clasper is entire and the caudal margin of the capsule has not the same shape as that of N. variabilis. The clasper of N. glauca re- sembles it somewhat, but the capsule is very different in shape. Fig. 7. Notonecta irrorata Uhl. The genital bulb of the male of this species is very different from the others in possessing a conspicuous fingerlike process on the ventral side. This is usually lighter in color than the rest of the bulb. Material examined from Ithaca, New York, and Wellington, Ohio. Fig. 8. Notonecta sp. In this species the clasper is broad and massive and very shallowly bifurcate. From a study of some specimens collected by Chambliss at Knoxville, Tenn. These bugs in size and general appearance resemble JV. indica. The scutellum lacks the lighter margin, however. Fig. 9. Notonecta insulata (Kirby). Genital bulb from a male specimen taken in California. Note the singular shape of the capsule along its ventral line. In profile it makes almost a right angle. Material from California and New York examined. Fig. 10. Notonecta undulata (Say). Genital bulb a little stouter than the majority of the others. The claspers strongly bifurcate, the caudal branch thick and blunt, the other long, curved somewhat mesally at tip. Material examined from Kansas, Missouri, and New York state. Fig. 11. Notonecta variabilis (Fieb.). Genital bulb from a male specimen in the Snow collections at Kansas University bearing label of identification by Mr. J. R. de la Torre Bueno (specimen from Staten Island). Material also examined from Ithaca, N. Y. The rather slender clasper is bifurcate at tip; the caudal branch more slender than the other. The quite evenly rounded caudal margin of the capsule is also different from those nearest it in appearance. The ventral keel of the capsule is present and differs in shape from that of N. undulata. Fig. 12. Notonecta glauca. The genital bulb or capsule from a male specimen given to me by Mr. J. R. de la Torre Bueno and bearing the locality label of Milano, Italy. The direction of the dorsal collar (D. C.) is directed backward somewhat instead of up- wards as in most specimens. The clasper is entire and the bulb lacks the ventral keel possessed by N. indica, N. undulata and N. variabilis. The specimen was slightly damaged and the delineation may not be exactly true. (332) PLATE XXXI. (333) PLATE XXXII. Fig. 1. Amhrysus melanoptervs Stal. The genital segment from a specimen in the Snow collection determined by Van Duzee. The segment is more elongate than A.. signoreti and the claspers more slender and truncate at tip. Another character in this group that may have possibilities is a chitinized flap that is present on the margin of one of latter abdominal tergites. Its position is on the right side in the material of the two species examined and distinctly different in shape. Fig. 2. Saldid. The exposed genital segment of a species common in Kansas. Note the shape of the claspers and the tip of the genital segment as compared with Pentacora signoreti Giier., fig. 6. Fig. 3. Amhrysus signoreti Stal. The genital segment from a specimen in the Snow collection determined by Van Duzee. The segment is plump and the claspers broad. The drawing is partly free hand and from dorsal view. This bug was taken by Doctor Snow at San Barnardino Ranch, Arizona (Cochise county). Fig. 4. Notonecta mexicana. The male genital capsule of this species is much larger in proportion to the size of the insect than any other member of the genus examined. It differs from the others in having the cephalic end larger than the caudal end and in having a greatly developed lobe before the clasper. The drawing is to about the same scale as those on plate 1, and the insect about the size of N. insulata and N. irrorata, the genitalia of which are shown on figures 9 and 7 of plate XXXI. Fig. 5. Oelastocoris variegatus (Guer.). The specimen from which this drawing was made bears Uhler's determination and was loaned for study by Mr. E. H. Gibson, custodian of the Hemiptera in the National Museum at Washington. The drawing is made from a ventral view of the bulb. In this genus the genital segment is asymmetrical, the right clasper (R. C.) being much more developed than the left (L. C.) and armed with short peg-like processes. The segment has revolved a quarter turn to the right so that the tips of the claspers are directed to the right instead of dorsally. The general features of the genital ai-mature are the same for all, but the western and eastern forms fall into two distinct groups as regards the shape of the right clasper. The right clasper (R. C, see figure) is produced on its caudal margin into a flat plate which bears a curved more or less finger-like process. The distal angle (a) which this plate forms with the shaft of the clasper is acute in all the western material and obtuse and sloping in all the eastern material examined. In Kansas we have both forms. A series from western Kansas (Pawnee county) compare closely with this Uhler specimen. As a whole, they are pebbled and colored like the sand of the river flats upon which they live. A few speci- mens are more obscurely marked. There is no perceptible difference in the male genitalia of the whole series, however. In the Snow collections under G. oculatus there are speci- mens from Bill Wins Ford, Arizona, taken by Doctor Snow. Some are distinctly mottled and others more obscurely marked. The crenations and angles of pronotal margins are as in the G. variegatus (Guer.), determined by Uhler. The right clasper is acute angled, also. They are certainly the same as Uhler's G. variegatus (Guer.). Fig. 6. Pentacora signoreti. The genital segment of a species common in the western portion of Kansas. Determined material by Van Duzee. The two species are here shown to suggest that a study of these parts should be made in making a study of the family. They may have some taxonomic value. Fig. 7. Gelastocoris oculatus (Fabr.). The specimens of the material from eastern Kansas, Tennessee, etc., as a whole, are less variegated in color pattern and from Mr. J. R. de la Torre Bueno's notes (in litt.) are probably G. oculatus (Fabr.). These all agree in having the obtuse and sloping angled right clasper. Kansas is splendidly sit- uated for a study of geographical convergence. Western forms and eastern forms meet and Upper Austral and Lower Austral life zones are present. Dr. C. H. Kennedy's study of the dragon flies has directed attention to this interesting feature. One of our graduate students is now engaged in working over the distribution of the toad bugs with this point in mind. A study of a wide range of material of each form will always be essential to the establishment of the range of variation in the species, and any character which is specifically discontinuous and unique to a species is always a welcome, discovery. (334) PLATE XXXII. INDEX. A. Abbott, 211, 216, 218. Abedus, 142. Aldrovandi, 13, 158, 190. Alexander, 50. Algre, 24, 101, 137, 242, 244, 248. Alisma, 160. Amoeba, 247. Arabrysus, 198. Amhrysus californicus, 199, 204. Avibrysus circumcinctus, 199, 201. Amhrysus guttatipennis, 200, 203. Amhrysus heidemanni, 199, 205. Ambrysvis, Key to species, 198. Amhrysus melanopterus, 199, 208. Amhrysus mormon, 199, 202. Amhrysus puncticollis, 199, 208. Ainbrysus pudicus, 199, 204. Amhrysus pulchellus, 198, 200. Amhrysus pulchellus var. pallidulus, 198, 200. Amhrysus signoreti, 200, 202. Amyot & Serville, 15. Ankistrodesmus, 246. Arcella, 247. Arctocorixa, 211, 212, 215. Arctorixa alternata, 27, 229. Arrows, 92. Auhauhtli, 37. Axayactl, 37. Back swimmer, 24, 32. Back swimmers (see Notonectidee) . Barber, 51. Bastin, 38. Batrachidea, 50. Beamer, 106, 208. Belostoma, 30, 144. Belostoma flumineum, 144. Belostmatidse, 8, 11, 12, 13, 23, 30, 35, 40, 44, 141. Belostomatida), Biology of, 142, 151. Belostomatida?, Key to genera, 141. Benacus, 30, 150. Benacus griseus, 150. Blanchard, 15. Blasturus, 161. Boatmen (see Corixidae). Bog moss, 33. Borner, 211, 238. Botryococcus, 246. Brimley, 150. Britton, 149. Brocher, 16, 43, 44, 94, 117, 157, 160. 180, 236. Buenoa, 30, 32, 35, 41, 42, 173, 177. Buenoa albida, 175, 175. Buenoa carinata, 174. Btienoa elegans, 174, 176. Buenoa, Key to species, 173. Buenoa margaritacea, 33, 174, 175, 194. Buenoa plotycnemis, 174, 176. Bueno, 15, 36, 40, 43, 46, 92, 93, 95, 96, 116, 117, 118, 135, 137, 139. 144, 145, 154, 155, 157, 159, 160, 161, 180, 183. 208, 209. Bugnion and Popoff, 238. Burmeister, 15. Butler, 101. C. Callibffites, 161. CallicorLxa, 211, 212. Camharus immunis, 216. Capsids, 50. Caraphractus cinctua Walker, 32. Carmine feeding experiment, 241. Cattail 24, 26, 33, 34, 93, 103, 244. Ceratophyllum, 208. ChalcididK, 32, 101. Champion, 46, 51. Chara, 177, 184. Chiloxanthus, 55, 59. Chiloxanthus stelluta, 59. Chironomus, 248. ChlorophyU, 35, 228. Chlamydomonas, 247. Cicadellids, 34. Comstock, 228. Conferva, 235. Corixa, 211, 212. Corixa orivara, 235. Corixidfe, 8, 11, 23, 24, 26, 31, 32, 34, 35, 41, 43, 44, 96, 178, 180, 182, 186, 190, 193, 197, 210. CorixidsB, biology of, 215. Corixidas, Key to genera, 211. Corixid eggs, 25. Corixids as food, 37. Cosmarium, 246. Crambus, 101. 22 — Sci. Bui. — 1669 (337) 338 Index. Crayfish, 215, 216. Crustacea, 35, 102, 161, 178. Creeping water bugs (see Naurcoridse ) . Curicta hotvardi, 152. Cyclops, 35, 158. Daphnians, 34, 35, 138, 158, 179. Dawson, 35. DeGeer, 13, 14, 91, 117, 158, 208, 234. Diatoms, 35, 245, 247. Desmids, 35. Dogs, 16, 158. Duckmeat, 245. Duck-weed, 101. Dufour, 15, 117, 208, 219, 238. E. Ecology, 17, 28, 38, 180. Economic importance, 17, 35. Ege, 43. Electric light bug, 141. Elodea, 177, 221, 244. Embody, 245. Enoch, 160. Entomostraca, 35, 37, 42, 177. 186, 191, 197. Epistyllis, 146. Eschscholtz, 15. Essenberg, 117. Euglense, 35, 242, 244, 245, 247. P. Fabricius, 14. Fallen, 15. Feeding habits of aquatics, 33, 34. Fish, 177, 193, 228, 236. Fish eggs, 158. Fontinalis, 159. Forbes, 216. Form and Function, 38. Fragilaria, 246. Frisch, 13, 151, 158, 208. G. Gage, 36. Galgulidte (see Gelastocoridaj). Gelastocoridue, 8, 11, 20, 29, 39, 40, 42, 45. Gelastocorida', Biology, 49. Gelastocoridae, Key to genera, 46. Gelastocoris, 46. Gelastocoris, Key to genus, 46. Gelastocoris oridatus, 34, 4". Gelastocoris variegatvs, 47. Gelastocoris liciniis, 47. Geoffrey, 13, 14, 157, 211. Gerridas, 8, 11, 12, 24, 25, 29, 40, 106. GerridsB, Biology of, 116, 121. Gerridffi, Key to genera, 107. Gerris, 29, 32, 42, 107. Gerris argenticollis, 108, 111. Gerris buenoi, 108, 111. Gerris canaliculatus, 108, 112. Gerris conformis, 108, 109. Gerris gillettei, 108, 109. Gerris, Key to species, 108. Gerris marginatus, 25, 26, 34, 108, 110. Gerris orba, 108. Gerris remigis, 32, 34, 108, 116. Gerris robusta, 108. Gesner, 13. Giant water bugs (see Belostomatidm) . Gonatonzygon, 244. Gregarine, 32. Gyrinidw, 181. H. Hagemann, 16, 237. Halobates, 30, 107, 116. Halobates micans, 116, 120. Halobates sericevs, 116, 120. Harvey, 142. HebridcTB, 8, 11, 12, 29, 33, 39, 82. Hebrido?, Biology of, 88-91. Hebridae, Key to genera, 82. Hebrus, 29, 82, 85. Hebrus burmcistori, 85. Hebrus concivnus, 86, 87. Hebrus consolidus, 86. Hebrus sohrinus, 86, 87. Hebrus, Key to species, 86. Heidemann, 92. Heterotrichs, 244, 247. Hewitt, 157. Hibernation of Notonectids, 32. Holmes, 160, 161. I Hoppe, 43, 180. Howard, L. O., 148. Hydrobatidaa (see Gerridae). Hydrodictyon, 101. Hydrometra, 26, 39, 41, 91, 101. Hydrometra australis, 91, 92. Hydrometra, Key to species, 91. Hydrometra martini, 34, 91, 92. Hydrometra, parasite of, 32. H'ydrometridfB, 8, 11, 12, 25, 26, 29, 91. Hydrometrida:', Biology of, 92, 99. Hydrachnids, 31, 182, 231. Hydrophilidte, 159. I. loscytes, 56, 76. loscytus politus, 76. loscytus politus var. flavicoslo, 77. Jassids, 117. Johannsen, 181. Juncus, 34. Index. 339 K. Kennedy, 89. Key, habitat, 29. Kirby, 96. Kiritshenks, 161. Kirkaldy, 15, 31, 36, 37, 41, 79, 92, 96, 158, 165, 208, 235, 236. Kulgatz, 140, 160, 179. Lace bugs, 50. Lamarck, 14, 15. Lamprocanthia, 56, 77. Lamprocanthia crassicornis, 77, 80, 81. Laporte, 15. Latreille, 14, 79, 234. Leach, 15. Lemna, 92. Lethocerus, 30, 42, 148. Lethocerus americana, 40, 149. Lethocerus uhleri. 149. Limnobatidse (see Hydrometridse). Limnoporus, 107, 112. Limnoporus rufoscutellatus, 112. Limnodytes gerriphac/us March, 32. Limnodytes setosus, 32. Locomotion, 39. Lucas, 158. Lundbeck, 121. M. Macrovelia, 122, 127. Macrovelia hornii, 127. Marshtreader (see Hydrometra). Marshtreaders, 24. Martin, 92, 93, 95. Marsilia, 144. Mason, 40. Matheson, 149. Matheson and Crosby, 32. May fly larva, 158. Meneville, 15, 36. Meriam, 13, 36, 246. Merragata, 82, 83. Merragata brimnea, 83, 84. Merragota foveatn, 83. Merragota, Key to species, 83. Mesovelia, 39, 42, 99. Menovelia mulsanti, 24, 33, 34, 100. Mesoveliidse, 8, 11, 12, 25, 26, 29, 99 Mesoveliidee, Biology of, 101-106. Metrobates, 29, 107, 113. Metrobate.s hesperius, 114, 119. Miall, 195. Microcanthia, 56, 74. Micranthia hwnilis, 74. Micranthia pusillo, 75. Microvelia, 8, 25, 26, 39, 42, 122. Microvelia albonotata, 124. Microvelia americana, 125, 235. Microveiia atrata, 123. Microvelia horealis, 34, 123, 137. Microvelia frontinalvi, 125. Microvelia marginata, 127. Microvelia robusta, 126. Microvelia aignota, 126. Microvelia, Key to species, 122. Midges, 34, 99, 117, 248. Mites (see water mites). Moneywort, 33. Monony.x, 48, 51. Mononyx juscipes, 48, 51. Montondon, 46, 154. Mosquito larvae, 161. Mosquito wrigglers, 34, 96, 97. Moss, 93. Mouffett, 13, 158, 190. Mougeotia, 245. Mymaridse, 32. Naucoridae, 8, 11, 12, 31, 40, 42, 198. Naucoridce, Key to genera, 198. Naucoris, 208. Naucoris cimicoides, 235. Needham, J. G., 8, 11, 150, 151, 182. Nemotode worms, 242. Nepa, 13, 30, 152. Nepa apiculala, 152, 157, 158. Nepidje, 8, 11, 12, 40, 44, 151. Nepida?, Biology of, 157, 164. Nepidse, Key to genera, 152. Nerthra, 48. Nerthra stygica, 48. Nitelia, 208, 248. Notonecta, 13, 30, 32, 35, 41, 166, 179. Notonecta glauca, 179, 180. Notonecta howardii, 167, 168. Notonecta insidata, 168, 173, 180. Notonecta indica, 167, 168. Notonecta irrorata, 32, 33, 167, 171, 177, 180, 182, 183. Notonecta lutea, 33, 117, 172. Notonecta mexicana, 167, 170. Notonecta monteznma, 168, 172. Notonecta raleighi, 167, 169. Notonecta shooterii, 168, 172. Notonecta uhleri, 167, 170, 180. Notonecta undulala, 96, 167, 169, 177, 180, 190. Notonecta variabilis, 167, 169, 180. Notonectidffi, 8, 11, 12, 23, 26, 30, 31, 42, 44, 117, 164. Notonectidre, Biology of, 177, 198. NotonectidfB, Key to genera, 165. Notonectid eggs, 25. O. Ochteridae, 8, 11, 29, 39, 42, 51. OchteridsB, Biology of, 53. Ochterus americanus, 53. 340 Index. Ochterti,s banksi, 52. Ochterus flaviclavus, 52. Ochterus, Key to species, 51. 01igocha?tes, 35, 242. Oliver, 14. Ormerod, 161. Orthoptera, 39. Oscellatoria, 244, 245, 247. Ostrocods, 24, 26, 34, 35, 42, 96, 97, lO; 138, 161, 177, 186, 191, 193, 248. Oviposition of aquatics, 33. Palmocorixa, 186. Palmoeorixa, 211, 212. Palmocorixa, Key to species, 213. Palmocorixa buenoi, 27, 213, 221. Palmocorixa yiUettii, 213, 214. Palumba, 92. Paramecium, 247. Parasites, 182. Parasitism, 31, 32, 231. Parshley, 51. Pediastrum, 248. Pelocoris, 198, 205, 208. Pelocoris biimpressus, 206, 207. Pelocoris caroHnensis, 205, 206. Pelocoris femoratiis, 206, 207, 209. Pelocoris, Key to species, 205. Pelogonus, 51. Pentacora, 55, 56. Pentacora hiria, 57. Pentacora ligata, 58. Pentacora signoreti, 56. Pettit, 160. Phyllopods, 186. Plant lice, 101, 102. Plea, 12, 30, 35, 41, 165, 177. Plea minutissiina, 179. Plea striola, 33, 166, 177. Polygonum amphibium, 235. Potamogeton, 101. Prestwichia aquatica. 32, 160. Proctrotrypidre, 32. Protozoa, 242. Protozoa, 35. R. Ramphocorixa acuminata, 33, 211, 212, 215. Ranatra, 13, 30, 31, 32, 153, 158. Ranatra brecivolis, 155. Ranatra americana, 154. Ranatra annulipes, 159. Ranatra kirkaldyi, 154. Ranatra nigra, 154. Ranatra protcnsa, 156. Ranatra quadridentata. 158. Ranunculus aquatiles, 179. Rathke, 235. Reaumur, 13, 14, 15. Redfern, 195. Regembart, 180, 208. Respiration of aquatics, 43. Reuter, 9, 11, 54, 211. Rhagovelia, 30, 122, 128, 139. Rhagovelia armata. 128, 130. Rhagovelia distincta, 128, 129. Rhagovelia obesa, 40, 128. ^ Rhagovelia phimbea, 128, 130. Rheumatobates, 30, 33, 34, 42, 107, 115, 120. Rheumatobates, Key to species, 116. Riley, C. F. C, 117. Riley, C. V., 148. Riley, W. A., 181. Rivuiaria, 246. Ripsel, 13, 14, 157, 158, 208. Rotifers, 35, 242, 244. S. Salda, 55, 59. Salda anthracina, 61, 80, 81. Salda coriacea, 60. Salda littoralis, 59. Saldid!©, 8, 11, 12, 18, 26, 29, 33, 39, 42, 54. Saldidse, Biology of, 79. Saldinre, Key to genera, 55. Saldoida, 78. Saldoida cornuta, 79. Saldoida slossoni, 78. Saldula, 55-62. Saldula conflventa. 63. Saldula dispersa. 65. Sahhda elongata, 72. Saldula explanata. 64. S(ddiila interstitialis. 65. Saldula laticoUis, 69. Saldula luctxiosa, 73. Saldula higubris, 72. Saldula major, 62. Saldula opacula, 70. Saldula orbiculata, 63. Saldida pellita, 71. Saldula rcperta, 67. Saldula saltatoria. 73. Saldula scotica, 71. Saldida separata, 66. Saldula sphacelate, 69. Saldula pallipcs. 68. Saldula zanthoehila, 68. Savigny, 15. Say, 36. Scenedesmus. 35-244. Schmidt, 144. Schummel, 15. Scirpus, 157. Scott, 101. Sedge, 103. Severin & Severin, 145, 158. Index. 341 Shamrock (water), 101. Shephard, 181. Shore bugs (see Saldid»). Slater, 144. Smartweed. 93. Smith Pond, 17, 20. Smoky Hill river, 19. Snails, 149, 208, 248. Soars, 31. Sphagnum, 33, 93. Spike rush, 33, 34, 93. Spirogyra, 35, 37, 93, 228, 240, 243. Springtail, 101, 102. Striders (see Gerridse). Swammerdam, 13, 36, 91, 151, 157, 158, 161, 190. T. Tenagobia, 211, 212. Tenagogonus, 107, 112. Tenagogonus franciscanvs, 113. Tenagogonus hesione, 113. Tenagogonus hyalinus, 112, 118. Tettix, 50. Tetraspora, 242, 244, 246. Thomas, 36, 235. Tigny, 14. Tillyard, 230. Tingidida), 34. Todd, 145. Trepobates, 29, 42, 107, 114. Trepobatei pictus, 115, 119. U. Uhler, 15, 50, 51, 53, 54, 79, 80. 144. 208. Van Duzee, E. P., 9, 11, 153. Velia, 30, 42, 122, 131, 139. VeliidjB, 8, 11, 12, 29, 30, 40, 121. VeliidsB, Biology of, 134. VeliidiB, Key to genera, 122. Velia annuUpes, 131, 135. Velia australis, 131, 132. Velia braehialis, 131, 133. Velia, Key to species, 131. Velia stagnalis, 131. 132. Velia watsoni, 134. VorticeUa, 146. W. Walchenser, 1 4. Ward and Whipple, 32. Water mites, 31, 182, 222. Water scorpion, 13. 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VII. Nos. 1 to 17, price, $3; supply large. VIII. Nos. 1 to 10, price, $3; supply large. IX. Nos. 1 to 21, price, $3; supply large. X. Nos. 1 to 15, price, $3; supply large. XI. Price, $3; supply large. i BULLETINS OF DEPARTMENT OF ENTOMOLOGY. "Two Grain Insects." V, L. Kellogg (with F. H. Snow). "Common Injurious Insects of Kansas." V. L. Kellogg. "The Horn Fly of Cattle." V. L. Kellogg (with F. H. Snow) . "The More Destructive Grasshoppers of Kansas." S. J. Hunter (with F. H. Snow). "Scale Insects Injurious to Orchards." S. J. Hunter. "Alfalfa, Grasshoppers, Bees; Their Relationships." S. J. Hunter. "The Honey Bee and Its Food Plants in Kansas." S. J. Hunter. "The Green Bug and Its Natural Enemies." S. J. Hunter. "Report of Results of University Research Commission on Horse Plague." S. J. Hunter, A. L. Skoog, W. K. Trimble, N. P. Sherwood. "Orchard Problems and How to Solve Them." H. B. Hungerford. "Studies in Kansas Insects." 1. Grasshoppers; Melanopli of Kansas. P. W. Classen. 2. Grasshoppers; CEdipodina; of Kansas. R. H. Beamer. 3. Dragonflies of Kansas. C. H. Kennedy. 4. Scale Insects Injurious to Fruit and Shade Trees. P. W. Law- son. 5. Spring Cankerworm and Its Control. W. H. Wellhouse. Applications should be made to the State Entomologist, University of Kansas. UNIVERSITY GEOLOGICAL SURVEY OF KANSAS. General Stratigraphy of Eastern Kansas; exhausted. ,; General Geology of Western Kansas; exhausted. Special Report on Coal; weight, 4 pounds. Upper Cretaceous Paleontology; exhausted. Gypsum and Gypsum Cement Plasters; weight, 2 pounds. Carboniferous Invertebrates and Cretaceous Fishes; weight, 4 pounds. . Special Report on Mineral Waters; weight, 3 pounds. Special Report on Lead and Zinc; weight, 4 pounds. Special Report on Oil and Gas; exhausted. 1913. Special Report on Well Waters in Kansas; weight, 1 pound. 1915. Crystalline Rocks in Kansas; weight, 1 pound. 1917. Oil and Gas Resources of Kansas. MINERAL RESOURCES OF KANSAS. Report for 1897, 1898, 1900-'01, 1902; exhausted. Report for 1899, 1903; postage, 4 cents each. The reports and bulletins of the University Geological Survey of Kansas and the reports on the Mineral Resources of Kansas are for free distribution on receipt of the proper postage, or may be sent by express, charges collect. Where weights are given consult your postmaster for parcel-post rates. Applications should be made to the State Geologist. Volnnie I, 1896. n. 1897. III, 1898. IV, 1898. V, 1899. VL 1900. VII, 1902. VIII, 1904. IX, 1909. Bulletin 1, ti 2, a 3, Date Due