4 V ON AQUATIC CARNIVOBOUS COLEOPTERA y OR DYTISCID^. BY DAVID SHARP, M.B., HON. MEM. OF THE INSTITUTE OF NEW ZEALAND: MEMBER OF THE ENTOMOLOGICAL SOCIETIES OF LONDON, FRANCE, BERLIN, STETTIN, BELGIUM, AND SWITZERLAND, ETC., ETC. Plates VII. to XVIII. [FROJI THE SCIENTIFIC TRANSACTIONS OF THE ROYAL DUBLIN SOCIETY. VOL. 3. SER. IL} DUBLIN: PUBLISHED BY THE ROYAL DUBLIN SOCIETY. PRINTED BY ALEX, THOM & CO., 87, 88, & 89, ABBEY-STREET, THE QUEEN'S PRINTING OFFICE. FOR HER MAJESTY'S STATIONERY OFFICE. April, 1882. TABLE OF CONTENTS TO VOLUME II. (SERIES II.) Pages 1. — Ob.seivatious of NebiiliB aaJ Clusters of Stars made with the Six-foot aucl Three- foot Reflectors at Birr Castle, from the year 1848 up to the year 1878. By the Right Houourable the Earl of Rosse, ll.d., d.c.l., f.r.s. Plates I. to VI. Read Febi-iiary 18th, 1878. Published — Parts 1 and 2, August, 1879 ; Part 3, Juue, 1880, . . . . . . . . . 1 to 178 Appendix, . . . . . . . i to v 2. On Aquatic Carnivorous Coleoptera or Dytiscidse. By David Sharp, m.b., etc. Plates VII. to XVIIl. Read May 16th, 1881. Published— April, 1882, , 179 to 1003 II.— ON AQUATIC CARNIVOKOUS COLEOPTERA OR DYTISCID.E. Br David Sharp, m.b., Hox. Mem. of the Institute of New Zealand: Member of THE Entomological Societies of London, France, Berlin, Stettin, Belgidm and Switzerland, &c., &c. Plates VII to XVI fl. [Read May 16tli, 1881.] 1. Prefatory. Some years ago. I commenced a special study of the Dytiscidoe, with the object of increasing the recorded information about this family of beetles. I had been previously, for a considerable period, specially interested in the family, and when beginning my studies, I hoped particularly that I should be able to improve the very imperfect classification in vogue, and I also wished to know whether a detailed knowledge of the varied structural peculiarities of the species would be consistent with the belief that the present condition of these had been reached by a process of gradual modification or evolution, and whether an intimate acquaintance with the intricate relations existing between tbe diverse components of the family would render credible the hypothesis that these are descended from a few ancestors or even from a single very remote ancestor. Now that I am offering to the Royal Dublin Society the work that has occupied me for some years, I feel that I must in the first place make an apology for its imperfections and omissions. I have accomplished but little — so little that, in comparison with what I have left undone, I feel it to be almost as nothing. Our knowledge of the earlier stages of the life of Coleoptera, and of their meta- morphoses is very imperfect, and in the case of the aquatic species there are special difficulties in the way of acquiring information of this nature, thus it happens that we know very little of the life histories of the DytiscidjE — so little that it cannot aid at present in the classification of these insects, and I have therefore limited my efforts to producing an arrangement based on the structures of the perfect insect. Even as thus limited the work is very incomplete ; existing collections though tolerably numerous are very imperfect ; a large number of species are knc'Wii onlv by a single, or by very few individuals, and thus the basis of their taxonomy — ti <• accurate delineation of the characters of morphological species — is still very in- complete, while the important questions of the amount of variation exhibited by the different forms, and of the limits and nature of their distribution on the eaith's surface can be dealt with only in a very inadequate manner. Moreover, I have made no reference to internal anatomy, for in view of the present position of this department of entomology it is clearly premature to attempt to make a classification founded on both the internal and external structures ; and TSlAKS. rot. dub. 80C. N.S., VOL. II. 2 B 180 On Aquatic Caraivorous Coleopfera or Dytisc'ahe. I haw; not endcavoureu to explore the internal anatomy ut" the multitude of species, for to do this in such a way as to be trustworthy for taxouomical purposes would be more than the work of a lifetime. Thus the memoir I offer to the Society is a mere imperfect sketch of the characters of the species of aquatic carnivorous beetles, and a contribution to a synthetical or natural classification thereof based on tlie external structures of the perfect insects. I have commenced with a compai'ative sketch of the variations of structure exhibited in the family, and at the same time have touched slightly on its similarities to, and difierences from the terrestrial carnivorous Coleoptera. The next part is intended to characterize all the species I have examined, and to enable the name, and as far as possible the special characters of anj^ species to be recognized with facilit3\ For those using the work for these purposes it is an advantage to l)e as brief as possible, and I have consequently avoided lengthened descriptions of points common to a considei-able number of species, and have endeavoured to limit the diajT^noses and remarks to a combination of characters sufficient to distinguish a species from the allied ones known to nie. The DytiscidiB however offer in this respect a serious difficulty : owing possibly to the comparative want of variet}^ in the external conditions in which they exist, the species resemble one another much more closely than is the case in other families of beetles ; there is in fact less variety in such details of sculpture and colour as are found in other families to afford important assistance in the recognition of species ; there is too a great monotony of shape or form ; indeed we may say that just as the various ships and boats devised by man have a greater resemblance to one another than have the various carriaijes and machines for travellino- on land, so do the species of water beetles show a less variety in these respects than do the dwellers on land. The discrimination of the species of Dytiscidoe is therefore not an easy task, and recourse must be had for tlie purpose to differences in the minor structural peculiarities. I have found that as I'egards the structure of the feet and legs the distinctions between the sexes vary much from species to species, and I have accordingly given particular attention to these and other secondary sexual characters ; it has been the more advisable to do so because this has hitherto been much neglected, and because the sexes frequently differ so much in their characters that they cannot be recognized as one and the same species unless these distinctions are specially noted. The analytical tables are merely intended to facilitate the determination of the species by curtailing the number of descriptions to be perused, and with this object the characters used have been arbitrarily selected, and such as are easily observed have been preferred. I have not tabulated the species of each genus, because the attempts I made to draw up such tables satisfied me that in a great number of cases I could not do this in a manner likely to be practically useful. On Aquatic Carnivorous CoIeo2)tera or Di/tiscid(c. 181 Eleven hundred and seventy-one species are distinguished, in a more or less imperfect manner; and in addition to these there are recorded in the Munich catalogue of Coleoptera or in recently published works some three hundred or more names, a considerable proportion of which probably represent species unknown to me. As these descriptions are extremely scattered in works in various languages, and frequently rare or difficult of access, they are reprinted for the convenience of future workers {vide page 649). In the nomenclature of the species I have used the system of priority as set forth in my pamphlet on the object and method of zoological nomenclature. I treat the two words forming the name of each species as being practically one, and retain them unaltered, thus for the present abandoning the Linneean idea of making the name of a species indicate its position in classification. The arguments I have used in the paper referred to have not, so far as I am aware, been answered ; and further reflection on the subject has convinced me that the system is not only logically con- sistent, but is likely to be practically useful, and capable of serving as a permanent basis for a system of synthetical classification. A large and constantly increasing portion of the space of descriptive zoological works is occupied by lists of synonyms : this burden is already so great that it has become a serious question whether zoologists can reduce the extent of these synonyms without danger to the precision and continuity of their w^ork. The plan I have adopted of retaining as the name of the species, the original name, will serve the purpose of limiting future increase of synonyms ; for a very large proportion of those usually attachedto zoological descriptions consists in following the classificatory changes in the name of the species that inevitably result from the unfortunate method of making the name of the species dependent on that of the genus. Another aid is the relegation of pure synonyms (that is such as are not resultant from classification changes but from sheer error or accident) to catalogues published apart from descriptive works, where these synonyms may be recorded once and for all and then done with ; a catalogue should in fact serve as the place of final interment of these unfortunate results of accident, neghgence, or haste. We possess already in the Munich Catalogue of Coleoptera a work in which a large proportion of synonyms are well recorded, and I have considered the existence of this valuable production sufficient reason for omitting the synonymy already recorded therein, and have contented myself with citing in the alphabetical index of this work such names as are necessary to establish a harmony between it and the catalogue in question. For a similar reason it forms no part of my plan to give a history of the previous and present condition of the taxonomy of the family, nor a list of all the writers who have described species belonging to it : both of these can be gathered from the pages of the Munich Catalogue. The earlier descriptions are scattered in the pages of zoological and entomological works from Linnseus till the time of Aub^ ; special reference is due to the work of the last named author, who in 1S38 published the 3 B 3 1 82 On Aquatic Carnivorous Coleoptera or Dytiscidae. " Species gcndral des Colcopteres — Hydi-ocanthares et Gyriniens." The descriptions of this justly respected writer are very good, and may continue to be consulted with great advantage in respect to the shape, colour, sculpture, and similar specific characters of the 317 species known to him. A reference to each species described by Aube in the work alluded to, as well as to the species subsequently described by various authors, will be found in the Munich Catalogue. I would also specially call attention to the work of Schiodte (" Genera og Species af Danmarks Eleutherata") published at Copenhagen in 1841, because six of its valuable plates consist of figures of structural details of these water beetles. The carnivorous water beetles are included in the second volume of the Munich Catalogue which was published in the year 186 8, and in the period that has since elapsed several authors have given us works or notes relating to these creatures. Of such, Crotch " Revision of the Dytiscidje of the United States," (Tr. Amer. Ent. Soc. 1873), Sahlberg "Enumeratio Coleopterorum Carnivororum Fennise (Notiser ur Siillskapets pro Fauna et Flora Fennica Forhandligar, XIV, 1873), Regimbart Etude sur la classification des Dytiscidse (Ann. Soc. Ent. France 1878), and Bedel " Faune des Coleoptercs du bassin de la Seine," (published as a supplement to the Ann. Soc. Ent. France, IS SO,) deserve special notice, inasmuch as their works are of a systematic character, and contain a ([uantity of information arranged in such form that it may be easily consulted and used. Numerous entomologists and two museums have contributed to the completion of the work, by communicating to me either extensive collections, or a few rare and little known .species. The Musee Royal d'Histoire Naturelle at Brussels, and the Museo Civico di Storia Naturale of Genoa have allowed their collections of this family to remain in my hands for a considerable period, and the Comte Henry de Bonvouloir of Paris has entrusted to me for several years the whole of his collections of Dytiscidoe, comprising the larger part of Dejean's original collection of the family, and many of the specimens actually described by Aube, and for this assistance I offer him grateful acknowledgment. To Dr. Lcconte, of Philadelpliia, I am greatly indebted for the loan of a series of typical specimens of the species described and named by him in his numerous valuable entomological memoirs. Dr. Horn, of Philadelphia, M. Leon Fairmaire, of Paris, The Rev. A. Matthews, of Gumley, Leicestershire, Prof Sahlberg, of Helsingfors, and Herr Ernst Wehncke, of Harburg on Elbe, have all loaned nie specimens of which I had need and for doing this I heartily thank them. I will also mention here that I adopted the plan of determining collections and specimens sent to n)e by means of a number attached to the species instead of a name ; the number used by me for this purpose will be found attached to each species in the prestnt work, and is placed after the description of the habitat in each case. The concluding part of this memoir is intended to be a contribution towards a natural classification of the species previously characterized. This classification I On Aquatic Caniivorous Cohoptera or DytisciJcje. 183 have attempted to make on a purely synthetical method. Linnaeus and the more im- mediate of his followers made their classifications by a deductive or analytical method. Natural objects were taken for granted as forming three separate kingdoms, animal, vegetable, and mineral — and then each of these hypothetical or axiomatic kingdoms was divided and subdivided until the genus and species were reached and defined. This method — most useful in the early stages of scientific develop- ment— is being giadually replaced by an inductive or synthetic system. In other ■words species are studied and defined and then treated as units whose relations to one another may be exhaustively considered. This method has been clearly recognized by fTuxley as will be seen by consulting his paragraph on morphological groups ("Man. Anat. Invertebrated Animals," p. 17) : and it is quite evident that only by this synthetical method can we hope to ascertain whether genera and the more complex aggregates have any real existence in nature, or whether they must remain — as they undoubtedly are at present — merely conventional arrangements. On tlie Linntean method it may be said with perfect truth that the genera were made by the system, whereas it is clear that on a natural science method the system must be made and built up in accordance with the actual structures ascertained detail by detail. If there be an order in Nature our zoological systems must be made in accordance therewith, and representative thereof; if there be no such order, we may then revert to the Linnafjan method, for this is well adapted for purposes of artificial arrangement. At present I scarcely think there is any conscientious naturalist who after a careful review of facts would say whether there are or not in Nature, independent of classifications, such things as genera. I believe, if we limit our view to the creatures coexisting at the present moment, no naturalist could be found who would venture to deny the^existence of species as real and objective. It is in fact perfectly clear that the hosts of individuals livingaround us are arranged in clusters or groups, isolated from other clusters or groups ; and although there may be doubts as to the actual number of such clusters — and doubts as to whether certain masses of individuals form two isolated clusters or only one, yet no practical naturalist will be found who will deny the reality of the existence and isolation of such clusters, and it is these we call species. The nature of the connection between the individuals of these clusters, and the kind of isolation existing between them are most difficult questions, but their discussion has been commenced by Lamarck, Darwin and others; and these problems are now recognized as legitimate subjects for scientific investiga- tion, although perhaps but few perceive their excessively complicated and difficult nature. If, however, it be granted that species have a real existence, and if their characters have been well ascertained, it is clear that we may then deal with them as units to be classified and arranged, preliminary to considering the question whether these species are, like the individuals of which they are composed, arranged in naturally isolated clusters. This is evidently a much more complex question to deal winh 1S4 On Aquatic Carnivorous Coleoptcro. or Dtjtiscidie. than that of species; l)ut il" we suppo.se it to be answered in an affirmative sense^ we may then treat these complex aggregates as themselves units, and study them in the same way as we have supposed to be already done in the case of genera and species. Looking at taxonomy in this aspect, species are the units of the classifier, genera are aggregates of the fir.st degree, groups of genera aggregates of the second degree, and so on. Whatever view be taken as to tlie nature of genera, it will at least be admitted that there does not prevail among naturalists at present so great concord as to their limits, as that which we find to exist about species. It is undoubtedly the case that an attempt to define genera in a thoroughly natural manner is much more difficult than the study of species ; while an additional obstacle is thrown in our way by the fact that we are not yet acquainted with all existing species, so that any da}^ by the discovery of a new and intei'mediate form two apparently distinct genera may be connected together. This process of forming genera by synthesis — by the accord existing between species as to the whole of their characters other than specific — has notwithstanding its difficulties jirogressed in a more or less recognized manner, and is no doubt destined to su])plant completel}' the process of ai'tificial classification; and there can I think be but little doubt that the perfection of the miethod will be, for a while at any rate, accompanifd liy an increase in the number of primary aggregates recognized by zoologists. The enormous increase that has already occurred in the number of genera has occasioned much discussion and given rise to considerable complaint against those who make new genera ; and in point of fact the history of systematic zoology pi-esents us with a picture of constant protest by the older naturalists against the uuiltiplication of genera by their younger fellows. And it nuist be admitted that the increase has indeed been enormous ; Linnseus only admitted 354 genera as composing the whole animal kingdom (" Systema NaturiB," Ed. xii) ; the nuiuber at jiresent recognized could not be readily ascertained, but it is something enoimous ; there are I believe about ten thousand genera recognized merely among the beetles, and I anticipate that this number will increase to forty or fifty thousand. I do not myself feel alarmed at this extraordinary nuiltiplication, but there is one poini connected with it that is certainly to be regretted ; it is the corresponding increase in the number of generic names ; the enormous growth in this I'espect has already brought us to the unfortunate pass that few of us, even tliough we are specialists, recognize, much less understand, the generic names even of the depart- ment to M'hich we have given particular attention ; and thus the names of genera come to have but little value. Seeing then how uncertain are the limits of genera nt present, and iiow doubtful it is what kind of relation the genera we now adopt may bear to those of the future when systematic zoology shall have assumed a more periect form, we may Avell consider whether some method cannot be devised to limit the incnnise of generic names, or at any rate to render their recognition a (Jn. Aquid'tr Carnivorous Coleoptera or Di/ti-!cida\ 185 matter uf subordinate importance. And it seems to uie that a muiierioal linear arrangement might here be of assistance. If genera were numbered consecutively, ^nd the number habitually quoted, we should recognize tlie position of the genus much more easily by means of the number than we do by means of a name; for instance if we have the knowledge that there are about 700 genera of Longieorns and have an idea of the method on whicli they are arranged, and if we knew that in a numerical arrangement of the Coleoptera the Longieorns begin at 3,000, and run on to 3,700, it is clear that we shall at once recognize any number between the tuo just named as indicating a genus of Longieorns : and further that we shall be able to recall in a more or less vague manner, what part of the Longicorn family it belongs to ; whether it comes near the beginning or end of the family and consequently «ome ally with which we are specially familiar. There is a further advantage in a numerical expression of classification, inasmuch as it gives us a prospect of being -able in the futui-e to indicate in an exact manner, by means of a numerical formula the true systematic value of any aggregate we are required to deal with, and thus to ascertain for instance the true difference between the faunfe of two countries we might wish to compare in this respect. A numerical system applied in the way I have indicated, can however express only a linear arrangement, and as this can never be more than an approximation to a natural classification, it is clear that a simple numerical system can never do more than express feebly the complex, relations existing between animals ; moreover, it could only be of full service when applied systematically to all the animal kingdom ; and I have accordingly adopted it here as an adjunct of my classification without attaching to it any considerable present importance ; but still it seems possible that it is in the direction of numerical expression of classification that we may hope for real improvement. In the second synthesis the genera are treated as units to be arranged into groups ; and in the third synthesis these groups become the units of which tribes -are formed ; and this metliod of prooeiKling from the simpler to the more complex aggregates is carried on till ultimatel}^ such questions would come to be considered -as whether there really exists an isolation or division of organic beings into vegetable and animal kingdoms. In the present memoir this method of classifica- tion is carried only to the extent of a synthesis of the fifth degree. I have already mentioned that during the progress of the work I have had my -attention frequently directed to those problems as to evolution and descent in which naturalists at present are so greatly interested, and the points I have more particularly kept in view were these two. First, are the structures of iiiese creatures of such a kind as to make one believe they may have arisen by gradual modification of a precedent different structure ? and second, are the various re semblances, or affinities as they are called, among the different species such as to make it appear probable they are the results of genetic community of descent 186 On Aquatic Carnivorous Coleoptera or Dytiscidoe. from one ancestor or a few ancestors. The first of these questions I can answer decidedly in the affirmative. That these water beetles have arrived at their present condition by a process of gradual modification or evolution, seems possible and con- sistent with their structures ; indeed I may go farther and add that there are some points of their structure which are not comprehensible on any other hypothesis known to mc. On the second part of the problem I proposed to myself, viz, whether the great number of species of Dytiscidae now existing have probably descended from one or a few ancestors, 1 have come to a decidedly negative conclusion. After a care- ful study of the various affinities and points of structure, I cannot consider them as indicating genetic community, and I have come to think that it is more probable that each species has been evoluted along a distinct and separate line of descent. Thus I fancy I see in tliis mass of twelve hundred species, not a development from one ancestor but the results of twelve hundred lines of development. The numerous cross-7-elations between the various aggregates, and the points of re- semblance between different species seem when first examined almost irresistibly to suggest that they may be accounted for by assuming descent from a common ancestor, but more careful study instead of rendering this more probable has always had tlie opposite result. One conclusion, I think, I can state almost positively; it is this, that whatever may prove to be the connexion between existing and extinct morphological forms, there is no relationship of an ancestral or genetic kind to be traced between actually existing species. This result although negative is not without significance, for among these twelve hundred species there are many in a later or higher stage of evolution than others, and yet in no case have I been able to consider that a lower existing form is ancestral to a higher existing form ; the theory of descent from a few ancestors would however lead us to suppose that, in some cases at any rate, parental species and descendant species should for a time co-exist. In the various syntheses forming the third part of this memoir there will be found some sketches illustrating the kind of reasoning that has brought me to these conclusions. Although quite inclined to agree with Huxley's remark (" Manual of the Anatomy of Invertebrated Animals," p. 4) " that the growing tendency to mix up setiological speculations Avith morphological generalisations will, if unchecked, throw biology into confusion," yet 1 think it must be admitted that if there is ta be any expression of opinion on aetiology, it is well that it should be plueed in proximity with the observations on which it is founded, for only in such ca-e can its true value be appreciated, and I hope in the present instance it will be found that the few remarks I have made on these points in no way detract from the value of the observations with which they are associated. I will ask also per- mission to make now some brief remarks on these setiological problems, my object being not to advocate any particular theory, but rather to reiterate the extremely difficult, nature of these questions, and specially to point out that even if the theory On Aquatic Carnivorous Coleoptera or Dytiscidce. 187 of evolution be true, community of descent is not rendered probable thereby. I have already stated that the existence of taxonoraical seiies does not really lend any support to the theory of a few ancestors, and I would now add to this that similarity of structure as to some particular point also fails to establish the pro- bability of community of descent ; for if one hypothetical ancestor can have developed a point of structure, equally can two or more have done so. Semper has recently pointed out that " every character which can be regarded as a true sign of large groups of animal forms, may be ultimately traced to the stage at which it first appeared, and where it was a character of ada23tation " ("Animal Life," notes p. 407). This is perfectly correct, and to it may be added the fact that if we look at some character that is now ^Drobably in process of adaptation, we find that the adaptation is going on not in one favoured species, but in a number of allied species. For instance, it is the rule in the Dytiscidte that the meso- and metasterna are connected together in the central line of the body ; a considerable number of the group Hydroporini form however an exception to this rule, and one of these genera, Deronectes, differs only from Hydroporus by the fact that this connection is wanting in the former while it has been attained in the latter genus ; but a study of the species of Deronectes seems to show that the connection m question although not at present existing is j^i'obably being gained by many of the species if not actually by all of them. Now if a structure be acquired simultaneously by a number of distinct species, it is clear that similaiity of structure does not indicate community of descent. Again if I am right in supposing the species of Deronectes are acquiring this structure by the want of which they are solely dis- tinguished from Hydroporus, it is plain that these two distinct genera are, so far as can be seen, in process of becoming one : the real difference between them is in fact one of time — Hydroporus has gained a particular structure before Deronectes has done so. Such facts apjjear to me gravely opposed to the a priori probability of descent from a few ancestors. But if the resemblances between animals do not justify the theory, there remains on the other hand the important fact that the isolation of species from one another is gravely opposed to its probability. Huxley has pointed out in his essay On the origin of .species (" Lay Sermons, Addresses and Reviews"), that the term species expresses two different sets of facts ; first, a set of morphological facts, or the agreement of series of individuals in points of structure ; and second, the physiological inductions that animals consist of groups of individuals that are fertile inter se, but who do not produce fertile offspring when crossed with members of other groups ; and in the same essay he has stated that when we look at the facts from the point of view of the morphological agreement between indi- viduals then the theory of community of descent is possible or probable, while if we bear in mind the jihysiological isolation of species then the theory is unsatisfactory. The arguments of Huxley in this essay appear to me very good, except that as I have already pointed out the morphological facts do not when carefully considered sujjport TRANS. ROY. DL'B. SOC . N.S., VOL. II. 2 C 188 On Aquatic Carnivorous Colcoptcra or Dytiscidce. the hypothesis to any great extent. I think his argument might be carried a step farther, and it might be pointed out that whereas the acceptation of the theory of evohition in no way diminishes the importance of the physiological differences between species, it does on the other hand very much detract from the value of the morphological agreement between them ; at any rate it is I think clear that the physiological distinctions between different species may be real and permanent even though the structural characters by which they are represented in our classifications shall prove to have been fluctuating or temporary. We know from paleontology that the totality of the organisms of the present day is very different from what it was formerly as regards the morphological structure ; but we di not finrl traces of any facts that would lead us to believe that the earlier organisms were not isolated into separate species just as the present ones are. While the excessive resemblance between the ova of different animals coupled with the fact that these similar ova develope into totally distinct organisms, leads us to believe that distinctions of a most profound character may have been present in the earlier and simpler organisms even though the imperfection of our means of investi- gation would not allow us to assert this from the study of the organisms themselves. Thus it seems to be a perfectly credible theory that the isolation of species from one another is indicative of deej) seated distinctionsthatmayhaveexistedpriorto the more conspicuousmorphological differences ; and itappears probable that though the species of a late geological epoch may be the descendants of differently structured animals of a former epoch yet the physiological distinctions may have been more permanent, or in other words that the lines of descent have been perfectly distinct. It will at any rate be incumbent on those who advocate community of descent to show how and when the physiological distinctions became established, and at present, so far as I know, there is no evidence of the beginning of such distinctions ; we are not aware of any process by which a group of individuals fertile inter se, becomes divided into two or more distinct, mutually infei'tile groups. But those who maintain the community of descent tacitly assert that such a jirocess has been the order of Nature. There seems good reason for supposing that the physiological distinctions between species are correlative with molecular distinctions that we do not at present comprehend ; and if so we may hope that the advance of the science of pure molecular physics will help to solve these problems. But if we are not content to wait patiently for such a period, and at present allow our imaginations to attempt to penetrate very far back into the darkness of the past, we may well ask those who maintain the descent of organisms from one or a few ancestors, what reason have they for supposing — what satisfaction can there be in believing — that only one or two or a few primitive organisms or germs existed ? Surely, if the passage from matter in a state of inorganic arrangement to a state of more complex organic arrangement took place naturally — under the influence of On Aquatic Carnivorous Coleoptera or Dijtiscidce. 189 far reaching and enduring law — the transition must have been long enduring in time and wide spread in space. Can we believe it possible that universal law should have resulted in the production of a single inconceivably minute portion of organic matter, from which all the enormous aggregate of organisms now around us has been produced in its almost unthinkable variety by a process of simple reproduction? No, I think that whatever the mode or modes may have been by which inorganic matter became organic, it will surely prove more credible that the passage extended over a vast period of time, and occurred in numerous places, and was not limited to one instant of time and a single pin point of space. It we say this we admit that it is possible that there have existed distinctions in the individual masses of oi"ganic beings from their very beginnings, and it is quite conceivable that in these aboriginal molecular diflerences may have originated the present physiological species distinctions, — that these are in tact absolute and direct continuations of primeval molecular ditferences of constitution ; and it is credible that from such a myriad beginning, through the enormous ages of the woi'ld there have developed the vast multitudes of species of plants and animals amongst which we live. If anything like this has been true, we need not necessarily adopt any theory of community of descent, but we may believe that each species is a distinct record of the past conditions in which it has existed, and that resemblance in structure of two different species is the result of similar growth under similar conditions. I shall not at present allude farther to the difficulties that surround the theory of community of descent, but I may remark that even if it should prove that we must abandon the hope of tracing the pedigree of all creatures back to a single organism, this in nowise detracts from the importance of biology. We are not called on to abandon the attempt to understand the relations between existing and extinct morphological forms, species by species, and to trace the road by which existing structures have become what we see them. The theory of evolution is in no way connected with the hypothesis of common descent ; and by means of the perfected acquaintance with the structures of existing organisms we shall attain, and of the detailed knowledge we shall acquire of the special modifications that have taken place in myriad separate lines of descent on various parts of the earth's surface, we may well hope that we shall be able to read slowly but truly the great history of Nature. Bates has an admirable remark — (" Naturalist on the Amazons," Vol. II, p. 34.5) speaking of the local variations in the patterns on the wings of butterflies, he has said, " On these expanded membranes Nature writes, as on a tablet, the story of the modifications of species, so truly do all changes of the organization register themselves thereon. " By the evolutionist this sensitiveness thus truly claimed for the butterfly's wing, may logically be asserted to have always existed in all the structures of every species of the organic world. Every individual is a mass of 2 0 2 190 On Aquatic Carnivorous Coleoptera or Dijtiscidie. structures, each of which is a record of past action (of the discharge of function under curtain conditions) and thus in the structure of every organic being there is written a portion of the histoiy of the world. Just as the coarser facts of that great history are written in the forms of the hills and valleys, the shores and the abysses, so are the minute details recorded in the forms and structures of organic beino-s. To read that history and understand it, is the task of many generations, it is but recently we have learned that such a history exists to be read, and we have as yet scarcely mastered its alphabet. II. Comparative Review of the Structures of the Family.* Size. — The Dytiscidaj are of very variable size, Notomicrus brevicornis being only 1 mm. in length, while Megadytes ducalis attains nearly 50 mm. The most minute forms are found among the Noterides, Hydrovatini, Bidessini, and Hydro- porides ; the most massive amongst the Cybistrini and Dytiscini. The Noterides, Laccophilini, and Hydroporides, do not comprise within their limits any individuals so large as the smallest of the Cybistrini and Dytiscini ; and in respect of this point the Colymbetides and Hydaticides stand intermediate between the small insects and the large ones. The linear classification I have adopted agrees, as a whole, in a remarkable manner with the development in size of the individuals composing the groups : all the small forms come in the earlier half of the arrangement, while the massive Cybistrini terminate it. It may be truly said, in a generalized manner that the hiffher forms consist of individuals of much larsrer size than do the lower forms ; no doubt many exceptions to this generalization may be pointed out ; and much variety exists in respect of size within the limits of a single genus ; for instance, in Cy bister we have the little C. dehaani only 13 mm. long, while C owas attains 40 mm. of length. In Form the Dytiscidse show comparatively but little variety, in fact there is probably no other family of Coleoptera of equal extent so uniform in this respect. The outline is oval or oblong-oval, the grea,test breadth being usually attained a little behind the middle of the length of the body : considerable differences are found in the amount of elongation, sometimes the oval is so short that the outline approaches to the circular form, as is the case in many species of Hydrovatus and in Colpius, while in the case of Dyiiscus cicurus. Fab. (No. 95G, Ehantus,) the length is nearly 2^ times the greatest breadth ; all the intermediate grades of elongation occur. The extremely ^hort forms are found only among the smaller species. Sometimes the anterior extrem- lity of the body is broader than the apical, as in Matus, but more usually the reverse is the case, and in Thermouectes the hinder portion of the body is very much broader than the anterior half ; in certain rare cases the extremity of the body and the wing- * This sketch should form part of the fifth synthesis, but is placed in this position in conformity with the usual custom. On Aquatic Carnivorous Coleoptera or Djtiscidce. 191 -cases are so acuminate as to be spiiiose (Celina, Methles, some Hydrovati) ; this occurs only in species whose individuals are of small size, and in'all such cases the ■swimming legs are very feeble. The most remarkable peculiarity in the outline is its continuity, or freedom from interruption at the junction of the base of the prnthorax with the wing-cases : this continuity is frequently so perfect that no break in the regularity of the form can be detected at the spot indicated ; this is the case with all the higher forms, and the best swimmers. But there are in the family some exceptions in which there is a great break in the outline at this spot, the base of the thorax being much narrower than the base of the elytra (Vatellini, Tyndallhydrus, Andex, Anisomera) ; this discontinuity is always associated with a peculiarity in the sternal pieces ; in its extreme cases such as in the Vatellini, Andex, and Tyndallhydrus, the prosternnl process does not reach the mesosternal process, while in those cases where the discontinuity is less marked, it will be found that although the prosternal process ma}' attain the metasternum, the mesosternura is less completely vertical in its direction than usual ; this will be found to be the case in Agabus cephalotes and in Dytiscus dorsalis (No. 630, Hydroporus). In the genus Deronectes it frequently happens that there is a considerable difference between the .sexes of one species in respect of the continuity of the outline of the thorax and wing-cases and it is always in the female sex that the continuity is the more broken. {See gen. Deronectes, No. 454 Hydroporus lareynei. No. 455 Hydroporus opatrinus, No. 472 Dytiscus depressus, &c.) The group Noterides presents a constant difference in outline from the other Dytiscidae inasmuch as the greatest width is in front of the middle of the body instead of behind it, and the species of this group have consequently the posterior portion of the body narrower than the other Dytiscidse, so that in them this part is less broad than the anterior half, while, as we have just seen, in most other species of the family the reverse is the case. As regards the convexity of the body the Dytiscidae show a great deal of variation, they are either subdepressed or little -convex, or they may be very convex ; the flattest or most depressed forms are found in the tribes Colyuibetides and Hydaticides, especially in the genera Copelatus, Lacconectus, Platynectes, and (a few) Agabus, while the most convex species are all small insects, of short form, such as Colpius and Suphis among the Noterides, most of the species of the groups Hydrovatini and Hyphidrini, and many of the group Bidessini ; in the Hydroporini some of the genera consist of convex forms, as in Hyphoporus, Herophydrus, Coelambus and Chostonectes ; while Deronectes and Hydroporus comprise forms which as a rule are much more depressed. The larger .and more powerful forms are usually of moderate convexity. When the convexity is very great it is as a rule confined chiefly to the under surface ; this is shown in a very marked manner by Pach3^drus and Hyphydrus ; in the convex Hydrovatini the convexity is obtained by about equal curvature of both the upper and lower surfaces; the Noterides display another peculiarity in this respect inasmuch as being 192 On Aquatic Carnivorous Coleoptera or DytiscidcE. always convex insects, the convexity is chiefly exhibited by the upper surface, the lower surface being unusually flat ; this peculiarity is however reproduced in the Colymbetides by many species of the genus Th'bius. It will thus be seen that as regards foiTo the Noterides are more peculiar and isolated than any of the other Dytiscidfe they being peculiar in their outlines both in the perpendicular and horizontal directions. Although peculiarities of form are usually to a large extent constant in allied species and genera and are even found to be characteristic in some of the still larger aggregates, yet exceptions are of frequent occurrence ; thus although a certain peculiarity of form is very characteristic of the genus Ilybius, yet there are certain species of Ilybius in which this peculiarity is absent, and which would therefore at first sight be considered to belong to the genus Agabus. In other cases variation in facies goes to a still greater extent ; thus the species of Lacconectus resemble Laccophili in size, form, and colour (although they have no approximation to that genus in any natural classification) and would scarcely be considered to belong to the Colymbetides by any one who examined them for the first time ; so too in many species of the genus Copelatus we find in their appearance but little of the Colymbetides, they more resemble the Hydroporides ; while certain Noterides although they have no aflSnity with the Hydroporides have been actually up to the present time always classified with them, and indeed placed in the genus Hydroporus. In Colour the Dytiscidie show much less variety than do the beetles dwelling on land ; brilliancy of colour is indeed quite absent. The usual colour is black, or yellow, or a combination of the two, or else a colour intermediate as it were between the two ; faint greenish, olivaceous, and brassy tints appear in the Colymbetides, Dytis- cini and Cybistrini ; the gayest and most variegate colouration is found in the tribe Hydaticides, where a mixture of black and yellow, in conjunction with a very shining polished surface gives rise to a very agreeable appearance : the colouration of these Hydaticides seems however to be in many cases so very inconstant that it can scarcely be of much service in defining the species, or in assisting in their recognition. In the ColjTiibetini, especially in the genus Rhantus, the el}i;ra are frequently of a yellow colour, which is however greatly obscured by a vast number of minute black specks or dots, these become in some species so dense and numerous that the wing- cases appear nearly or quite black, though frequently their speckled nature may be detected on a closer examination, especially when the lateral portions are looked at, the specks being there always less dense than near the suture. Several species of Hydaticus have a similar system of colouration and indeed so much resemble these Colymbetini that the species of the two widely separated genera are still much con- founded together, even by entomologists of good repute. In the genus Hyphydrus and in many Hydroporini {e.g., Coelambus and Necterosoma) the prevalent colour is yellow or yellowish with black marks on the upper surface forming a very irregular pattern ; the black marks being usually more or less elongate longitudinal lines, which On Aquatic Carnivorous Coleoptera or DijtiscidcB. 193 frequently run into one another laterally, so as not to be readily distinguished. Many species of Deronectes are also variegate with black and yellow, but the colouration is less distinctly of a linear character than it is in the insects just referred to. The Laccophilini vary much in colour, and are usually pallid ; frequently they are marbled with darker tints in a very indefinite manner, but some species {e.g., Nos. 90 & 97) become definitely and prettily marked : a very curious colouration is found in several species of Laccophilus (No. 156 and allied species) consisting of numerous very waved longitudinal dark lines, such as I have not seen in any other beetles. The most pallid species of the family are the two Eretes; E. australis is of an entirely pale colour, except that the wing-cases are covered with numerous rather large punctures, each of which is black; the second species of the genus (Dytiscus sticticus L.) has the same peculiarity, but has in addition a black fascia on the wing-cases, and frequently also another on the prothorax. The colouration of the wing-cases in Acilius resembles that in Eretes, except that the punctures are not so large and definite and the black colour is not limited to a single puncture, but connects two, three or more punctures together, giving rise to an irregularly speckled appearance approximating to that which I have already described as existing in the genus Pihantus : the irregular black fascia on the wings of Dytiscus sticticus just alluded to is produced in a similar manner. An entirely black surface is quite frequent in the family, and is found iu Noterides (Hydrocanthus Australasioe and H. funebris) in Hydrovatus, Hydroporus, and in numerous species of Agabus, iu Copelatus, Ilybius, Meladema, Cybister, &c. One of the most marked features of the colouration of the DytiscidfB is the fact that the lateral margins of the thorax and wing-cases are very frequently of paler colour than the rest of the upper surface, so that the body bears a more or less definite band of pale colour defining the outline of the upper surface; this yellow band finds its greatest development in the genera Dytiscus and Cybister, where it very frequently forms a perfectly definite lateral stripe of yellow colour ; in other genera, however, the stripe is not so distinct and definite {e.g., Ilybius fenestratus) and even in Cybister there are some species where the lateral margin is only indefinitely paler. In Ilybius and numerous species of Agabi which have a very dark coloured upper surface, a minute dot or dash of pale colour (or both of these) exists on the wing-cases, near the apex and lateral margin. In the Hydaticides the head and thorax bear with great frequency transverse marks of pale and dark colour on the head and prothorax and in numerous species of Dytiscus the whole of the prothorax is definitely margined with yellow ; and this is found again in two species of Cybister (Nos. 1,154 and 1,155). Although the colour of the body is so frequently black, the antennae nearly always remain pale; and it is the rule in the family that the palpi and legs, as well as the antennae are paler than the rest of the body ; the swimming legs however -are very frequently darker in colour than the other legs. Another peculiarity of frequent occurrence in the family, is the existence of two 194 Oa Aquatic Carnii'orous Coleoptera or Dytiscidw. indefinite spots of pale colour on the vertex of the head. The upper and under- surfaces of an individual are frequently very different in colour, the one being often pallid while the other is entirely or in great part dark {e.g., Dytiscus rceselii, Cybister, No. 1,169) : it is, I believe, always the case, when such discrepancy pre- vails, that the upper surface is darker than the under, and the latter is never much variegate as the upper surface sometimes is. As a rule the colouration of the two sexes of one species is nearly or quite similar, but to this there are a few singular and interesting exceptions ; the colour of the ventral segments in Hydroporus bistri- gatus (Bidessus, No. 299) is red in the female, black in the male ; in other species of Bidessus the same fact is repeated but not in so conspicuous a manner ; and we find it again among the Hydroporini in Coelambus (flaviventris, pallidulus, &c.) and in Hydroporus (Dytiscus halensis, No. 528) and again among the Colymbetides in Lancetes (Colymbetes prsemorsus. No. 916). In all these cases it is the males that have the ventral segments dark ; the repetition of this character in a few widely separated members of the family is a very interesting fact and should engage the attention of those who are interested in the questions of sexual colouration and selection. Indeed the whole family of the Dytiscidae is one that seems peculiarly adapted for throwing light on the questions of development and correlations of colour in the insecta, owing to the comparative simplicity of the facts ; most of the other families of insects show such a variety of colour and pattern that these are quite bewildering to any one who wishes to comprehend their meaning ; but the facts in the Dytiscida3 are less complex, and appear to be capable of being generalized in such a manner as to lead us to hope we may some day understand them. In the Sculpture of the surface we find that the Dytiscidae show less vaiiety than the other families of Coleoptera : to this rule there is however one most interesting exception in the fact that difference — and frequently extreme difference— in the sculpture of the sexes is of very common occurrence. Leaving this for a while out of the question, we may note that in the larger and in the more highly developed forms the surface is remarkably smooth and polished, and punctuation is nearly absent. In these smooth species there exist, however, with remarkable constancy three longitudinal series of fine punctures on each wing-case ; the series are about equidistant from one another and from the suture and outer margin, but frequently the external one of the three is much more indistinct than the others ; the persistence of these punctures throughout the family is remarkable, and seems to indicate that they have some considerable functional importance. In the coarsely sculptured and punctate species, they are more difficult to trace than they are in the smoother species, not only on account of the roughness of the surface, but probably also because they are really less developed. Each of the })unctures in these series bears a very fine hair, and sometimes the series can only be detected by means of these hairs, which can be distinguished as forming a series, although the punctures them- On Aquatic Carnivorous Coleoptera or Dytisciclce. 195 selves are lost amongst the general punctuation of the surface : in some cases (Colpius inflatus e.g.) I fail however to find any trace of their existence, and in. other cases {vide Laccophilus) they are excessively fine and indistinct, and as a rule are most regular and highly developed in large and smooth species such as we find in the genus Cybister ; as already remarked the outer series is more irregular and less persistent than the others, the sutural series being the most permanent. In the great tribe Hydroporides, the rule is that the upper surface of the body bears a true punctuation such as exists in many other families of Coleoptera, while on the other hand in the Colymbetides and Hydaticides, the opposite of this is the case — punctate species being exceptional. When present, the punctuation is of various degrees of fineness and coarseness, of density and sparsity, and is more usually seen on the elytra than on any other parts ; in many of the genera of Hydroporides, however, the hind coxae are very persistently punctate. The most remarkable punctuation occurs in the genus Pachydi-us, where certain species have a deep coarse punctuation on the wing-cases, the punctures moreover being more or less elongate in a peculiar manner. In many species of the genus Hyphydrus the elytra have a double punctuation, very fine punctures being mixed with considerably coarser ones. In the Agabini punctuation is nearly absent, the surface being either smooth, or — and this is the more frequent — covered with a very fine reticulation, formed by fine scratches placed so as to form meshes of irregular shape, and varying much from species to species. In Copelatus the sculpture is peculiar, and in its highly developed form consists of numei'ous longitudinal grooves or stri;B on the wing-cases arranged in a very regular manner. In the Colymbetides the most peculiar sculpture of the family is found : in Colymbetes the wing-cases are marked with transverse scratches, striae or grooves, placed very near to one another, and varying greatly from species to species. In Meladema {vide M. coriacea No. 978) a still more remarkable sculpture exists ; the elytra bear a large number of crescentic marks, which at the base are readily distinguished as such, but towards the extremity of the body become somewhat changed in shape and are very densely placed, so that an appearance is caused somewhat as if the surface were covered with overlapping scales. In the Hydaticides the surface is usually smooth, but in Eretes the wing-cases are marked with rather large quite round punctures, and in Acilius both the upper and under surfaces of the body are much punctate. In some species of Noterus there exists a peculiar punctuattion consisting of large round isolated punctures placed chiefly on the hinder part of the wing-cases ; and in Synchortus there is a somewhat similar sculpture, except that the punctures have their front margins somewhat raised giving rise to a peculiar rough appearance. It is worthy of notice that when punctuation is absent from the greater part of TRANS. ROT. DUB. SOC, N.S., VOL. II. 2 D 196 On Aquatic Carnivorous Coleoptera or Di/tiscido:. the upper surface, it still often exists to a greater or less extent on the apical portion of the wiug-cases [vide gen. Dytiscus, numerous species) ; and in the case of many species where the sculpture is peculiar, it frequently loses its peculiar character to a greater or less extent on this part and approximates on it more or less to ordinary punctuation. The anomalous Amphizoa presents us with the only case among the Dytiscidee where sculpture approaching to what is so usual in the Carabidse exists. In the latter family the elytra very frequently bear each eight or nine rows of punctures or striae or punctate striae, and in Amphizoa something of the same sort is found, but the sculpture in this case is without the regularity and definiteness it possesses in the Carabidae. Elevated costae or ribs on the wing-cases are very rare in the Dytiscidae, but occur in Darwinhydrus in conjunction with a punctate surface. In many Hydroporini the surface bears an extremely fine, short, depressed pubescence, but this is an exception to the condition usually prevalent. It is worthy of note that in nearly all the cases in this family where we find a peculiar sculpture present and well developed, we may see in allied species such sculpture present in a more rudimentary manner, and thus, as it were, indicating the steps by which it has been developed : this is well exemplified in the genus Copelatus (for notes on the sculpture of which, see page 201). The most remarkable fact in the sculpture of the Dytiscidae is the sexual disparity found in numerous species. This sexual disparity when present is of such varied character that I can here only allude to a few instances. In the first series — Dy tisci Fragmentati — no instances of well marked difference in the sculpture of the sexes have been recorded, but it is possible that the peculiar punctuation observed in certain species of Synch ortus {vide Hydrocanthus asperatus No. 18) may prove to be confined to the female sex ; the differences existing in the sculpture of the prosternal process in the two sexes of some sjiecies of Hydrocanthus is accompanied by a change of form in the part, and is no doubt a phenomenon of a quite different category to the remarkable distinctions in the sculpture of the upper surface found in the Dytisci Complicati. In many species of Hydrovatus the distinct punctuation of the female is the same as in the male, but yet the former sex has the surface rendered dull (coriaceous) by a very fine additional sculpture. In Hyphydrus we find that the females have the punctuation of the upper sur- face very obsolete in comparison with the males, but, nevertheless, in the former sex there is a development of an excessively fine sculpture which renders the surface quite dull : in this genus we find that certain species have two forms of the female, one of them resembling the male in sculpture while the other is dissimilar in the manner just described ; and this phenomenon of dimorphism in the females continues to be of very frequent occurrence in the Dytisci Complicati. Passing to the group Hydroporini we find that in Coelambus certain species show great differences in the On Aquatic Carnivorous Coleoptera or Dytiscidce. 197 sculpture of the two sexes ; thus in Dytiscus parallelo^rammus (No. 416) the female differs from the male in that the punctuation is very much finer and less deep and the surface is dull, and on examination with a considerable power of the microscope it is seen that the dulhiess arises from the surface being covered with a very dense minute sculpture of a peculiar character, but a good deal similar to that which is seen on a larger scale in Meladema coriacea (No. 978). In another species of Coelambus (Dytiscus impressopunctatus No. 409) the phenomena are quite different ; here the female usually resembles the male in sculpture except that its punctuation is a little denser and finer : there occurs however very rarely a second form of the female (Dytiscus lineellus Gyll.) very different from the male, the surface being much more finely punctured and dull, and on examination with a considerable power of the microscope it is seen that the dullness arises from the surface being covered with an extremely fine obsolete sculpture of a reticulate nature such as is seen in Agabus. In the large genus Hydroporus the females frequently differ in sculpture from the males in a more or less conspicuous manner, and the difference is sometimes dimorphic {vide Hyphydrus memnonius No. 558). In the Agabini we find in the genus Agabus that sexual differences of sculpture are of frequent occurrence : the differences is sometimes slight as in the case of Dytiscus guttatus (No. 670) where the female has the sculpture a little coarser than in the male ; or it may be very considerable as in A. lecontei and A. griseipennis (No. 731 and 732), where the male is less but the female is more reticulate than is usual in the genus ; or the sexual differences of sculpture may be variable as in the cases of Dytiscus congener (No. 706), and Dytiscus bipustulatus (No. 751), and in these cases the variations seem to be, to some extent at any rate, dependent on the locality the specimens inhabit. In the genus Copelatus a difference in the sculpture of the two sexes is very fre- quent, and the differences are in some species very great, in others only slight, and are quite as frequently found on the surface of the prothorax as on the wing-cases ; they usually consist of very short linear impressions, or fine, rather irregular scratches, dimorphism of the females is occasional, and when it exists is strongly marked, the female being either similar to the male in sculpture, or having a large area of the surface covered with an additional sculpture (vide Copelatus neglectus No. 841). It should be remembered that this genus is unique among the Dytiscidae by reason of the existence in it of a remarkable sculpture common to the two sexes : this non-sexual sculpture is of quite a similar nature to the sexual sculpture of other genera : the impressions on the thorax of Colymbetes sulcipeunis (No. 895) and the regular grooves on its elytra are just such as would (from what exists in the females of other genera) make one suppose them to be a female sexual sculpture, and yet they are equally developed in both male and female ; it is further interest- ing to note, that the females of the species I am alluding to (and of other Copelati) have an additional sexual sculpture consisting of some extremely fine irregular a D 3 198 On Aquatic Carnivorous Coleoptera or Dijtiscidce. scratches on the wing-cases : it might therefore be roughly said that in Copelatus the males have gained a highly developed and pseudo sexual sculpture as ■well as the females, but that the latter have in addition to this a minute sculpture of a different character and confined to their sex. In the genus Coptotomus there exists a minute difference in the punctuation of a portion of the wing-cases, the punctures in the female being more elongate than in the male. And in Matus (Colymbetes bicarinatus No. 1)07) the females have the upper surface less shining than the males, owing to the existence of an extremely minute, almost impercep- tible, sculpture, which appears to be slightly more developed in the former of the two sexes. In the genus Rhantus sexual differences of sculpture are usually either absent or very slight, but in some species become important. Thus in Dytiscus bistriatus (No. 949) the female may on a very careful examination be seen to possess a slight develojjment of a more coarse reticulate sculpture than the male on certain spots situated along the lines of serial punctures ; and in Dytiscus pustulatus (No. 945) there are two small patches of a similar but deeper reticulation, one on the outer, and the second on the middle of the two rows of serial punctures, some little distance behind the base. In Pthantus anisonychus ? the sculpture on the outer and basal portion of the wing case, is a good deal deeper than in the male ; and in Rhantus discedens (No. 938) a deep coarse sculpture exists in the female on the part just mentioned ; while in Dytiscus notatus (No. 947) the whole of the wing- case, except a small portion at the outer and apical part, is covered Avith such sculpture : in this latter species however the female is sometimes smooth like the male, and individuals occur in which the sculpture is intermediate in extent between these two extremes. The peculiar sculpture of the genus Colymbetes exhibits some very interesting sexual peculiarities ; although in several species no appreciable difference between the sexes in this respect can be detected, yet in others very notable differences exist ; in Colymbetes sculptilis (No. 968) the peculiar transverse scratches of this genus are placed closer to one another in the female than they are in the male ; while in Dytiscus dolabratus (No. 971) and in D. striatus (No. 972) the female peculiarity is that the scratches are very much deeper than in the male ; in Colymbetes exaratus (No. 966) the strice or scratches are a little deeper and a little closer together in the female than they are in the male, and moreover in the former, the basal portion of the wing-case is rendered very dull, by the development of an excessively minute sculpture (consisting of very small longitudinal corrugations) which is quite absent in the other sex : in Colj'mbetes dahuricus* the sculpture of the female presents very exceptional peculiarities, it is decidedly finer than in the male, but it is more irregular, owing to the transverse scratches, being less elongate, and so running much more frequently into one another, and the surface is duller than in the male owing to the greater development of an exces- * There is some little doubt whotlier the specimens of this species I here allude to are really the sexes of one and the same species. On Aquatic Carnivorous Coleoptera or Dytiscidce. 199 sively minute interstitial sculpture, having a somewhat granular appearance. Passing to the Dytiscini we meet in that group with some most remarkable facts : in the genus Hyderodes the females are usually smooth and polished like the males, but they are dimorphic, inasmuch as a second form of the female is met with (apparently only rarely) in which the surface is excessively rough, the whole of the upper surface, except the head, being covered with deep coarse erosions or corru- gations, irregular in shape and direction. In the genus Dytiscus considerable dis- crepancies exist among the various species in the sexual sculpture ; in D. punctulatus the female has ten grooves on the basal portion of the wing-cases, and the whole of the rest of the upper surface, including the interstices of these grooves bears a close fine punctuation, while in the male the grooves are wanting, and the elytra are punctured only on the apical portions ; the female in this species has also even the undersurface rendered dull over a considerable portion of its area by the •existence of fine, short scratches or reticulations which are not found in the other sex ; in D. fasciventris the facts are similar except that the fine sculpture is less extensively developed, so that as regards this latter peculiarity the sexes are more alike than they are in D. punctulatus. In Dytiscus habilis, in D. hybridus, and in D. verticalis the females have no grooves on the wing-cases, but they differ from the males by a greater development of the punctuation on the apical portion of these parts, and also by possessing an additional fine punctuation on the lateral basal portion of the wing-case ; in D. verticalis this additional punctuation is very small and unimportant ; the females of these three species all possess too a con- spicuous special sculpture on each side of the prothorax ; in D. subllmbatus the female characters are approximately the same as in D. punctulatus and fasciventris, but in this species there also exist females differing in sculpture from the males only by their possessing a fine scanty punctuation on the lateral portions of the prothorax ; a similar condition is present in Dytiscus marginalis, the females differing greatly from the males by their grooved and much punctate surface, but individuals of their sex are found differhig from the males only by a slight punc- tuation on the thorax and a little greater development of that on the elytra. In D. circumcinctus we again find the females possessed of a grooved and much punctate surface, but here a second form of the female occurs quite without sexual punctuation or grooving of the wing-cases. The females in the genus Dytiscus differ then from the males by possession of a fine sexual sculpture, and by a groov- ing of the elytra, this latter feature is however not found in certain species, and in certain other species is sometimes present, sometimes absent, while the fine sexual sculpture of the females is more constant, but may also be occasionally quite absent, and is only present in its greatest development in such females as are sulcate. In the Hydaticides, we find certain species of Acilius possessing females with grooved wing-cases, but the grooves are very different from what exists in Dytiscus, they being but four (instead of nine or ten) in number, and furnished with a pubescence 200 On Aquatic Carnivorous Coleoptera or Dytiscidce. which is confined to them ; and the spaces between the grooves are without punctuation, while in the males all the surface is punctate ; the females of the difterent species of this genus differ much in their characters from one another as to the development of the grooves and the punctuation and pubescence, and in Dytiscus sulcatus (of the genus Acilius) we find a patch of pubescence occupying a depression on each side of the prothoras. In Thermonectes the surface is highly polished, and when the females possess a sexual sculpture, it consists of beautiful elongate punctures placed on the basal part of the wing-cases but not extending over a large part of their area. In Sandracottus the surface is very highly polished and the female is destitute of sexual sculpture. In Graphoderes the females are usually destitute of any sexual sculpture, except a slio-ht corrugation of the surface on each side of the prothorax, but in this genus we meet occasionally with a more extreme development of sexual sculpture than any found elsewhere in the Dytiscidee or indeed in the whole of the order Coleoptera, the surface of the wing-cases being rendered rough by a very coarse sculpture almost like tubercles (but not very different from what exists in Hyderodes) while the prothorax is covered with beautiful deep corrugations ; these exceptionally sculptured females are very rare and it has been thought they were only a second form of that sex in a species (D. zonatus) having usually smooth females, but I think more probably they belong to one or two distinct species of the genus. The Hydaticini are insects with a very smooth surface, and many species are without sexual sculpture, but others exhibit such well marked ; in this group the chief seat of the sculpture is a portion of the area of each side of the thorax, but sometimes also it is situate on the basal portion of the wing-cases ; it consists usually of coarse, short, irregular impressions, but little connected with one another, and sometimes there exists on certain individuals {vide in Dytiscus goryi No. 1020) only one or two such impressions ; in a few New World species however the sexual sculpture consists of a circumscribed, and remarkably well defined patch of quite fine sculpture on each side of the thorax, formed by very closely placed fine rugae {vide H. subfasciatus No. 1019). in the Cybistrini there is frequently present in the female, a highly developed sexual sculpture, consisting of fine anastomosing scratches, which frequently nearly cover the entire upper surface of the insect, but in other cases are restricted to a much smaller area, sometimes this sculpture is more developed on the thorax than it is on the elytra, while at other times we find the reverse of this ; in many species of Cybister there frequently exists a sexual sculpture so fine and slight that it can only be detected by a careful examination, and many females are quite smooth ; in this genus, great variation of the sexual sculpture is quite common in certain species : some species of Megadytes {vide M. steinheili No. 1108) show a most beautiful sexual sculpture, the prothorax being quite smooth, in great contrast to the wing-cases which are covered, at any rate on On Aquatic Carnivorous Coleoptera or Dytiscidce. 201 their basal portion, with regularly placed elongate Impressions ; the largest of the Dytiscidce, viz., Cybister giganteus No. 1117 and Megadytes ducalis No. 1118, have no sexual sculpture whatever : in Homoeodytes we find the females of two species to possess a most excessively fine sexual sculpture, consisting of extremely delicate, short scratches, giving rise to a silky appearance on the basal part of the elytra. From this imperfect review of the sexual sculpture of the Dytiscidas it will be gathered that much variety exists as to its character, and as to its degree of development, and that the occurrence of two forms of the female of a single species is not unfrequent in various portions of the family : there is considerable reason to suppose that the development of the sexual sculpture is to some extent connected with local and climatic conditions, and it may prove to be that it is of more frequent occurrence in temperate and cold climates than in warmer ones : if it serves any, or what purpose is still undetermined, but it is certainly amongst the most interesting peculiarities of the Dytiscidse, and of considerable importance in respect to its bearings on the questions of sexual variation and selection. The peculiar sculpture of the species of Copelatus is of much interest and well deserving investigation. In some of the higher forms of the genus (Col. sulcipennis. Lap. e.(j.) it appears as very deep and regular stria3 or grooves, to the number of 10, 11, or 12 on each wing-case, and extending neai'ly their whole length, but becoming finer at the extremity, where usually some of them are more abbreviated than others. In other species no trace of such striation can be detected ; but in some of these cases the fine punctuation of the wing-cases assumes the form of very short fine scratches, which while they may be very distinct in the female, can sometimes scarcely be traced in the male (C. simplex, Clk.) The scratches displayed in such cases frequently assume a different direction on the hinder portion of the wing-case, becoming transverse there, when they have a longitudinal direction in front (Celina australis No. 806) ; while in some other species only the transverse posterior scratches exist (as in C ferrugineus). In some of the cases where the elytra are truly striate, i.e. display elongate regular straight lines, it can be perceived that these are developed along the series of impressed punctures which are so constant a feature of the Dytiscidae ; this is not the case in those species, where the scratches are short, for they are not then naore developed near the series of the punctures than they are elsewhere ; so it would seem there are as regards the sculpture three ditFerent series of species, viz., 1, punctuation ordinary ; 2, punctuation elongate, and diffuse ; 3, punctuation -elongate, but only along the lines of serial (and secondarily of the interserial) punctures ; the punctuation of this latter category becoming in the most differentiated cases, highly developed symmetrical strise. It seems impossible to believe that the development of this beautiful sculpture can have been determined by the action of natural selection ; preserving those individuals of a species in which it was more developed than in others, for iu 202 On Aquatic Carnivorous Coleoptera or Dytiscidoe. certain species it is so excessively slight as to be almost iuappreciable, and the amount of variation to be detected in such cases being likewise very slight, one cannot believe in these slight differences of development exercising any appreciable effect on the existence of the creature. The sculpture however is most certainly cor- relative with sex even in its rudimentary forms; thus in Dytiscus agilis (No. 825) the female has the punctuation on the basal portion of the wing-cases more elongate than in the male ; and in the allied Copelatus atriceps the difference is exhibited in a still more rudimentary form : while in the very interesting C. dimorphus (No. 827) we have a species displaying true striation in a rudimentary form, and in the male in a much more rudimentary manner than in the female. And throughout the fjenus, wherever there is a difference it is that the females have the sculpture more developed than the males. We are entitled to believe then that whatever the influences may be that have brought about in Copelatus this peculiar sculpture, they are influences which have acted at first more strongly on the female than on the male, but that continued during a long period such disparity has disappeared, or tends to disappear. It may be thought that these strice were of assistance in giving holding to the claws of the male, and that their direction enabled the male tarsi to arrive at the position most convenient for supporting the insect during the process of fertilization, and that the sculpture first gained by the female, was transmitted by heredity to the other sex. But these suppositions do not seem to me very satisfactory. One does not see why the females should be in the scratched species more different from the males, than they are in the striate ones ; for certainly the influence of heredity or sexual transference must be acting constantly, and not confined to the higher forms of development of the sculpture ; and it is excessively doubtful whether the highly developed sculpture is as useful for this sexual function as the rudimentary form : for the beautifully perfect straight stria; and grooves do not seem to me adapted at all for serving a useful purpose of the kind above suggested; the twenty-four deep broad parallel striae on the wing-cases of Col. sulcipennis can scarcely serve as agents to direct the claws to their requisite position, and I am at a loss to see in what other way they would be useful. Besides this, it is worthy of remark that in numerous species where the striation has attained a great development (similar in each sex) there exists in addition a very fine true sexual sculpture, peculiar to the female. The generalization of the facts in accordance with any theory of common origin, or of natural selection does not seem therefore to be warranted ; but on the other hand the presumption that each highly developed sjDecies has reached its develojjment by passing through a series of lower stages similar to such as are found still existing as the maximum of development in other species, is perfectly satisfactory and indeed iserristible to the imagination ; and the conclusion I come to on this subject of striation is that if we could gradually subtract from a higlily developed species its On Aquatic Carnivorous Coleoptera, or Dytiscidw. 203 later acquisitions, and so go back step by step till we reached the striatiou in its rudimentary form, we should find it similar to, but not identical with, that of other species ; which is equivalent to saying that each species has had a truly separate line of development. As a striking instance of the probable truth of this statement, I would point to the New Caledonian Copelatus aubei — the species in which the striation of the elytra reaches its maximum. The locality where it is found is remarkably rich in possessing very diffei'ent forms of the genus ; one of these forms C. interruptus (No. 847) has a striation of the elytra quite peculiar to itself; the striae are twelve in number but they are fragmentary, and slightly irregular in a peculiar manner. Now the only other species having so many as twelve strios is the C aubei above alluded to, and on examining this species one is brought to remark that on the portion of the wing-case where the stritie are usually least perfect — the apical portion — they show a fragmentary condition similar to what exists over the whole elytra in C. interruptus. In addition to this there is a true highly developed submarginal stria in C. aubei, and in C. interruptus, this stria is not present but is represented by a regular series of punctures, which only require extension to form the stria as seen in C. aubei. Now both these species are highly developed ones, found in one (isolated) locality, and the conclusion that their similarities are due to similarity of environment, and their differences due to a different condition of more original punctuation, is perfectly satisfactory to my mind. 1 conclude that C. interrujjtus and C. aubei have been developed from similar (but not identical) primitive conditions ; and that the serial punctures which seem to determine the lines of development of the striation, were less regular in the primitive ancestors of C. interruptus, than they were in the primitive ancestors of C. aubei, and that as the resultant of this the former species as we now see it has less regular striation than the latter has. The Head in the Dytiscidee is of remarkably short, broad form, and is inserted on the prothorax in such a manner as to completely fill up the front part of the latter and so avoid any discontinuity of outline at the junction of the two ; it is considerably broader than long, and in Laccophilus, where the abbreviation is greatest, the width is about double the length ; its upper surface shows but little convexity, and is marked on each side, near the front, at a little distance from the inner margin of the eye, with an irregular depression or fovea ; and close to the suture with the labrum there is a transverse depression or short impressed line on each side; the clypeus is nearly always so completely joined to the posterior portion of the head, that the suture between the two is obliterated, although frequently its commencement can be traced near the eye, on each side, whence it extends inwards towards the anterior part of the irregular depression before alluded to ; in the genus Dytiscus (as also in Pelobius) the clypeal suture is distinct across all the width of the head, and in Meladema (especially in TRANS. BOY. DUB. SOC , N S., VOL. II. ' ^ 204 On Aquatic Carnivorous Coleoptera or DytisGid:ion is perfect. The side of the middle column is distinct in most of the Macro-Dytiscidse (see Dytiscus, Meladema, Ilybius), but when the mesothorax has lost almost absolutely its extension in the longitudinal direction and become merely a diaphragm between the meta- and prothoraces (Laccophilus, Hydrovatus, Hyphydrus), then the column is so compressed that it becomes a mere lamina, bearing two facettes for the accommodation of the front coxae ; the two sides which form the back of the column are quite concealed so that they can only be viewed by disarticulating the mesothorax, they form a part of the anterior portion of the articular cavities for the middle coxae. On Aquatic Carnivorous Coleoptera or Dytiscidoe. 225 The lateral wiiio-s of the medisternum are each very short in the lonoitudinal direction, and extend on each side so as to assist in forming the anterior portion of the middle coxal cavity ; they become each a little longer towards the outside of the coxa, where they terminate by the junction of the outer extremity with the lower portion of the epimeron ; throughout the family they are very constant showing no important variations in size and form. The larger portion of the area of the mesosternum is formed by the episterna ; each of which is a large piece rising from the upper edge of the side-wing of the medisternum directly over the middle coxa ; its upper extremity is shorter (in the true longitudinal axis) than the lower, and rises higher than the other parts of the mesosternum and plays an important jJart in the articulation of the wing-case ; the inner margin of the episternum is the border of the large foramen affording the means of communication between the prothorax and afterbody; this inner margin has the appearance of being a distinct piece, articulating at its lower part with the front piece of the middle column of the medisternum (referred to above as being probably a distinct piece) ; at its upper extremity this inner margin expands and becomes hollowed, in a more or less evident manner, and thus affords space for the expansion or play of the prothoracic stigma which lies immediately in front of it. The episternum although forming so large a portion of the mesosternum is of little taxonomic importance, as it varies very little throughout the family, it is remarkably large in the Noterides, and in Hydro vatus a large part of its area is impressed for the accommodation of the middle femur. It is on the episternum that the torsion by which the mesosternum becomes diaphragm-like, is effected ; the front edge always preserves the natural direction, but the episternum is more or less gradually bent, so that the hind part of the mesosternum is placed something like at right angles to the front edge, which thus appears to form a very short neck. The epimeron of the mesosternum is always smaller than the episternum, and its lower extremity always penetrates to the middle coxal cavity ; its inner (more correctly anterior) margin is closely connected with the episternum, the suture between the two being fine, but usually distinct, but in Bidessus and Sternopriscus it is most frequently very indistinct : the outer margin is applied to the front edge of the metathoracic episternum. The epimeron is always very short (in the truly longitudinal direction) at its lower part, but usually becomes broader as it reaches to the shoulder, and after its angle of junction with the humeral angle of the metathoracic episternum it again becomes narrower, so that it forms a rather irregular, narrow and elongate triangle ; in some cases, however, the epimeron becomes scarcely any broader at the metathoracic angle (Bidessus and Notei'ides) so that it may be described as linear, although in point of fact it always shows a well marked, sharply defined angle at its point of junction with the angle of the metathoracic episternum. In the Noterides the linear form of the epimeron is accompanied by a very large development of the episternum, but this is not the case 226 On Aquatic Carnivorous Coleoptera or Dytiscidve. in Bidessus, where the episternum and epiraeron are each small in area ; the Noterides are therefore distinguished by the sublinear epimeron and the fact that this is very small in comparison with the episternum. Although the epimeron is always smaller than the e2:)isternum, yet in the higher forms it increases so much in size that it becomes almost equal to the episternum in ai-ea {vide Laccophilus, Acilius, and others). Tlie upper extremity of the epimeron, extends the whole length of the mesosternal flank, terminating, at the upper articulation of the wing- case, behind the extremity of the episternum ; its upper edge is grooved to receive the margin of the inflexed base of the wing-case. There are some points specially characteristic of the mesothorax of the Dytiscidse, and a comparison of these with the Carabidte is of interest; they are — 1. The direction of the mesosternum ; 2. The magnitude of the anterior sternal pieces ; 3. The magnitude of the posterior piece ; 4. The separation of the middle coxee ; and 5. The penetration of the epimeron to the coxal cavity. 1. As regards the first of these, there does not exist to my knowledge any Carabid in which the direction of the mesosternum is so remarkably divergent from that of the meta- sternum as it is in most of the Dytiscidaj, and in the great majority of the members of the two families this difference is very considerable ; there are, however, some Dytiscidse — the Vatellini and Sternoprisciis, (and even a sjiecies of the genus Hydroporus, Dytiscus dorsalis No. 630) — in which the mesosternum has only to a comparatively slight extent assumed the diaphragmatic position it possesses in their allies ; and on the other hand in Systolosoma, Trachypachys and Cyclosomus of the Carabidfe, the direction of the mesosternum becomes to a great extent that of the DytiscidjB ; no absolute distinction exists therefore between the two families in this respect. 2. The medisternum, and the episternum are very much larger in the Carabidae than they are in the Dytiscidne (tlie head and prothorax must be separated from the afterbody before this can be appreciated). This distinction is remarkable and is no doubt correlative with, if not dependent on the fact that the presternum has a connexion with tliQ metasternum in the Dytiscidse, this being of course much facilitated by the abbreviation of the intervening mesosternum ; while as another explanation of the curtailment, we have the fact that the anterior part alluded to is prolonged to allow of a greater or less extent of rotation and nutation of the prothorax in the Carabidi:e, while in the Dytiscidse this power has been held in abeyance in consequence of the more supreme necessity for fixing and securing these parts to prevent the admission of water to the interior of the insect. Thus it is in the Carabidie where the head and prothorax are quite free and mobile that we find the greatest difference from the Dytiscidse in the point alluded to, while where there is a prosternal process in the Carabidge the medisternum and episternum become sliorter : Cyclosomus and Trachypachys, Systolosoma, with others of the fragmentary series of Carabidse (in which series it is that we find a prosternal process of not unfrequent occurrence) have therefore shorter anterior On Aquatic Carnivorous Coleoptera or Dijtiscidoe. 227 pieces to the mesotliorax than have the other Carabidse. In none of them, however, do I find the abbreviation to be so considerable as it is in the Dytiscidte; in Systolosoma for instance (the only one of the three genera just mentioned that I have been able to dissect) the middle of the mesosternum is decidedly more elongate than it is even in the most Carabid like of the Dytiscidaa — Amphizoa. In describing the medisternum {ante page 223) I remarked that its central column appeared to consist of two distinct parts, and fui'ther that the inner or front margin of the episternum had also the appearance of being a distinct piece connecting with the front jjiece of the central column. In the Carabida3 these pieces are still more distinct, and it is in fact by the much larger size of these front pieces of the medisternum that the mesosternum of the Carabidaj differs from that of the Dytiscidse. As the structure of the mesosternum in the Carabidee has not so far as I am aware been thoroughly examined, I must for the present leave this subject, merely remarking that in Carabus catenulatus the middle of the mesosternum appears certainly composed of three parts super- posed one on the other. The third point in which the mesothorax of the Dytiscidas differs from that of the Carabidaj, is the greater development of the posterior side piece in the former group ; this is, however, by no means constant, for in the whole of the ti'ibe Noterides, as well as in some Hydroporides, of the Dytiscidie, the epimeron is as small and linear as it is in most of the Carabidse ; and in Silphomorpha of the Carabidse, the shape and size of the epimeron is similar to the Dytiscidse, (except that it does not penetrate to the coxal cavity). Fourth^ the rule in the Carabidas is that the intermediate coxse are very distinctly separated, but in the Dytiscidse they are more approximate ; this however is liable to numerous exceptions ; in the Pseudomorphides (and according to Lacordaire in the Ozoenides), the middle coxse are very approximate as in the Dytiscidse, and the Dytiscidse themselves differ considerably in this respect, thus although the coxse are con- tiguous in Vatellini, they are in Hydrocanthini and Suphisini as widely separated as they are in Carabidse ; and even in some of the higher forms — as the Hydaticini — the separation of the middle coxse is moderately broad. Fifth, in the vast mass of the Carabidie, the mesothoracic epimeron does not penetrate to the coxal cavity, whereas in the Dytiscidaj it invariably reaches the cavity ; but the first, or fragmentary, series of the Carabidse resemble the Dytiscidse in this respect, the epimeron reaching to the cavity as in the water-beetles. Turning to the special points of approximation between the two families in respect of the mesosternum we find, first, that there is but little difference between the mesosternum of Systolosoma and Amphizoa, still the former is a little more Carabidiform than the latter in this respect ; and both differ but little from the Dytiscidse ; second, the mesosternum of Omophron is very similar to that of the Noterides ; third, although the Pseudomorphides resemble the Dytiscidse as regards the mesosternum, inasmuch as their coxse are approximate, and that sometimes TBANS. ROT. DUB. SOC, N.S. VOL. II. 2 H 228 On Aquatic Carnivorous Coleoptera or VytiscidoB. (Silphomorpha) its epimeron is Dytiscidiform in shape, yet the group differs widely from the Dytiscidce inasmuch as the anterior pieces are very large, and the epimeron does not penetrate to the coxal cavity. In Pelobius the mesothorax might pass as belonging either to Dytiscidse or Carabidae, the epinxeron being rather small and its superior metathoracic angle little developed, so that in this respect it is Carabidiform ; while as regards its direction it is indeterminate, and with respect to the size of the anterior pieces it is Dytiscid rather than Carabid. In the Haliplides too, the mesothorax fails to support their classification either with the Dytiscidse or Carabidse ; the epimeron is large, but quite different in form from any Dytiscidte, for it has no trace of any superior metathoracic angle, and its greatest length (in the true longitudinal direction) is not at the line of this angle, but near to the coxal cavity ; the anterior pieces are quite small, and different therefore from the Carabidse. The Metasternum. The metanotum is of much larger area than the mesonotum, but in those forms in which the mesothoracic scutellum is least developed (Hydro- vatini, Hyphydrini, Laccophilini, and, but not so markedly, Hydroporini) it is much smaller than in those having the scutellum largely developed and of very firm con- sistency, as it is in the Macro-Dytiscidse generally. It is of complex structure, and it appears to me very difficult to determine accurately of how many pieces it is essentially composed, and to decide as to their homologies. It is of course covered entirely by the elytra, and although it is horny, it is thinner than are the exposed parts of the skeleton. It is traversed in the middle, by a deep and broad longi- tudinal depression, into which is received an incrassation on the basal portion of the inner face of the suture of the elytra. In the middle in front it is armed with a small angular vertical projection, which acts to some extent as a support to the free extremity of the mesothoracic scutellum, and which probably represents a portion of the prrescutum, which is otherwise absent : this projection is not present when the scutellum is rudimentary (Hyphydrini, Hydrovatini, Laccophilini), and is small in the Noterides, and Hydroporini ; in fact its development appears to be strictly correlative with the growth backwards of the scutellum. The larger part of the metanotum is occupied by the scutum, which is divided in a more or less irregular manner, longitudinally and transversely so as to form four pieces. The anterior pieces — one on each side — are shining and glabrous, and are especially reduced in size in the Hyphydrini, Hydrovatini and Laccojihilini, while in the Noterides these plates are small, and placed chiefly in the vertical instead of in the horizontal direction. Behind these two anterior plates there are placed the two posterior plates of the scutum ; these are not shining like the anterior ones, but are dull and frequently bear a few hairs. Behind the scutum, the scutellum is visible as a transverse linear band on each side, but in the middle it has a considerable extension in the anterior direction, by encroaching on the hind border of the posterior plates of the scutum. The post scutellum is placed behind the scutellum, and on a rather On Aquatic Carnivorous Coleoptera or DytiscidcB. 229 lower level than it, it extends completely across the body as a horny band con- necting by its extremity with the metathoracic epimeron ; to its hind margin is attached the basal abdominal segment. In Hydrocanthus australasise this band is very peculiar, for instead of passing across the body in a straight line, it diverges backwards in the middle, so that between the scutellum and post scutellum there exists a large membranous space. The metasternum consists of two side pieces on each side, and a middle piece — the metasternum proper ; this last is of very peculiar form, its hind margin is very firmly connected with the front of the hind coxa3, so that these are frequently supposed to be a portion of the metasternum ; in the middle in front this latter stretches forward and extends between the middle coxse, so forming an intercoxal process ; on each side of this are the middle coxae ; an inflexed portion of the metasternum forms in fact the posterior half of the coxal cavity ; outside the coxae the metasternum comes in contact with its episternum, and forms a curved or oblique suture in adaptation with this part ; its hind border is encroached on by the exten- sion forward of the hind coxse, and thus between the episternum and the coxa, the metasternum is more or less — frequently excessively abbreviated — so as to form a wing, called the lacinia or wing of the metasternum ; in the posterior direction the metasternum projects farther back at the expense of the coxae, so forming in the middle behind a more or less acute angle ; thus the metasternum is elongate along its middle, but extremely short externally on each side. The intercoxal j^rocess in the majority of the Dytiscidis is connected in front with the fork of the metasternum, and when so connected it is marked in the prominent middle part with a groove or depression — the metasternal groove — for the reception of the apex of the prosternal process, which is usually lodged in it : the intercoxal process differs much in shape and in its various details, and is one of the best means of recognizing genera and species : when the mesosternal fork is not sufficiently elongate to reach the same plane as the front of the metasternum, then the apex of the metasternal process is curved or bent up, so as to enter the mesosternal fork (Dytiscus) or at least to touch it (Hyphydrus, Eretes) ; the nature of the intercoxal process seems chiefly to have been determined by the distance separating the middle coxae ; when the middle coxae are quite contiguous, and project from their cavities, then there is properly speaking no intercoxal process (Vatellini, Sterno- priscus) the middle of the metasternum showing merely a prominent angle behind, and in adaptation to the coxae ; where the middle cox^ are broadly separated (as in (Hydrovatini, Pachydrus) then the intercoxal process is correspondingly broad and short, and its connexion with the mesosternal fork is very intimate or exact, thus in Pachydrus each of its lateral angles projects and articulates with the raised angle of the extremity of the mesosternal fork, which in these cases is reduced, in the longitudinal direction, to a mere lamina, while the raised margin round the coxal cavity is continued inwards along the front of the intercoxal process ; in the 2 H 2 230 On Aquatic Carnivorous Coleoptera or Di/tiscidfe. Hydrocanthini and the Suphisini, the intercoxal process is very large, being both elongate and broad, and is nearly truncate in front, in adapatation to the broad truncate extremity of the prosternal process, the two edges of these pieces fitting together at their line of junction in a most perfect manner : usually the intercoxal process is impressed to receive the extremity of the prosternal process, and the metasternal groove thus formed, coincides in shape with that of the point of the prostei'nal process ; when the intercoxal process is very broad, (Hydrocanthini, Suphisini, Hydrovatini, Pachydrus) then it bears no groove, for the prosternal process is brought very closely into adaptation with the intercoxal process ; and there is in these cases excessively little mobility of the prothorax, these being the forms in which this characteristic of the Dytiscidae has become almost absolute ; when the intercoxal process is very naiTow, (as in many Agabi, especially group 12; Eretes, &c.,) then the groove is elongate, narrow, and indefinite, consisting of a mere depression along the middle of the process ; and when the prosternal process is short, feeble, and acuminate, which usually occurs in such forms as have the middle coxse rather approximate, and the intercoxal process more or less curved upwards at its extremity (as in Hyphydrus, Coelambus, and other Hydi-oporini in which the mesosternal fork is not connected with the intercoxal process) then it can scarcely be said that there is any metasternal groove present ; while its maximum of per- fection is attained in the Cybistrini, where it is deep, with very definite sides, and perfectly adapted to the prosternal process, but yet when the point of the process is slightly lifted allows some movement of extension between the prothorax and after- body. The central piece of the metasternum, is more or less produced behind between the front parts of the hind coxee, its sides usually meeting to form a more or less acute angle; in Hyphydrus however the posterior portion of the metasternum does not form an angle, but has a comparatively broad rounded extremity. From the front of the intercoxal process to its posterior angle the metasternum is usually elongate, but varies much in this respect and in Hydro vatus it is short and conse- quently its posterior angle is obtuse ; the greatest reduction of the middle of the metasternum occurs in the short globose Dytiscidse, and is exhibited by Suphis and Colpius, where its posterior part has scarcely any backward prolongation in the middle. Nearly always there is a fine longitudinal channel running along the middle of the metasternum, but this is frequently very obsolete. The most peculiar character exhibited by the middle of the metasternum, is that in the Noterini and Hydrocanthini, it is more or less raised or prominent, so as to form in conjunction with the prosternal process, and the middle portions of the hind coxae, a kind of broad flat keel, increasing in width as it progresses backwards; this peculiar structure reaches its greatest development in Hydrocanthus, and is without any jaarallel in other beetles. The laciniee or side wings of the metasternum are as it were compressed between the posterior coxse, lying behind them, and the episternum lying On Aquatic Carnivorous Coleoptera or DytiscidcB. 231 in front of them, and their form therefore depends largely on the shape of these adjacent parts : when the hind coxa, has become very large it forms an arch in front and thus encroaches on the lacinia, which suffers a corresponding diminution in area, but as its external extremity is fixed to the outer side of the coxa, and this does not grow forward so much as the middle does, consequently the outer portion of the lacinia extends backwards outside the arch of the coxa as a more or less slender band according as the coxa is more or less extremely developed ; the extreme forms thus assumed are very remarkable, (see Hyphydrus, Eretes, Laccophilus) ; in the genus Agabus great variation exists as to the size of these lacinise, and in most other genera considerable diversity exists on this point. Usually the outer extremity of the lacinia terminates as a more or less acute point, but in the Thermonectini and Eretes the lacinia becomes a little broader near its apex, thus giving rise to a peculiar shape, which in Eretes where it is most extreme, may almost be described as clavate, the extremity of the- wing appearing obtuse or almost rounded. In the Noterides the wing of the metasternum assumes a peculiar form characteristic of the tribe, but as this as well as some other variations, is cor- relative with the shape and development of the hind coxa, it will be better spoken of when those organs are described. In Pelobius and Amphizoa, the metasternum has near its hind margin in the middle a transverse line or suture, which is not present in any other of the Dytiscidae, although it is a nearly constant character of the Carabidfe. The metathoracic episternum is a large and conspicuous piece forming the shoulder of the metasternum ; it is nearly triangular in form, its front margin being in apposition with the hind margin of the mesothoracic epimeron ; the base of the triangle is adapted to the wing of the metasternum, and is curved in the Thermonectini and Eretes, Hyphydrus, Laccophilini, and in such other forms as have the hind coxae very largely developed, while in other groups it deviates but little from a straight line, till it is near the intermediate coxae, where it is always curved, sometimes (Hydaticus) abruptly so ; its inner angle penetrates to the middle coxal cavity in the Dytisci Complicati — a point of structure which has not yet been detected in any other Coleoptera — but in the Dytisci Fragmentati, it fails to reach the cavity, stopping short in the Vatellini at a considerable distance from the outside of the cavity, but in Laccophilus very nearly reaching to it. The posterior angle of the triangle extends as far backwards as, or even slightly farther than, the apex of the metasternal wing, and forms there a blunt, or rounded truncate angle, touching the margin of the elytron, or at a little distance from this : its third or humeral angle is covered by the wing-case ; the upper edge of the episternum just behind this angle shews a groove into which the inflexed edge of the epipleura fits. The anterior edge of the episternum is thickened so as to form a margin along its front, and when this margin is very large and much exposed as it is in Hydrovatus, and numerous others, it has 232 On Aquatic Carnivorous Coleo'ptera or DytiscidcB. extremely the appearance of being a distinct piece of tlie sternum, whicli however is not the case. The upper or outer portion of the episternum is, at any rate in its anterior portion, covered by the wing-case, and when the part covered by the wino--case is large, as in Hydrovatus, then the posterior extremity appears very slender and acuminate, but on the elytra being taken off it will be seen that in such cases the termination of the episternum is really obtuse, the greater portion of its area being turned upwards at an angle with the exposed portion ; this covered portion of the episternum may readily be mistaken for the epimeron, more especially as it is of a different texture from the exposed part, and is traversed by a sort ot line, having somewhat the appearance of a suture, between the covered and exposed portions. The epimeron of the metathorax, unlike the episternum — is very indistinct, and might on a careless inspection, be supposed to be absent ; it is however always present and is placed on the upper posterior portion of the episternum, but extends farther backwards, than this piece does ; the suture between the episternum and epimeron is covered by the wing-case, and is often very fine and indistinct, but is alwa3's conspicuous when the part is properly cleaned and exposed ; the episternum towards its extremity becomes, as above stated, narrower, and thus trenches away from the edge of the wing-case, and an angle is thus formed between it and the upper and outer portion of the hind coxae, and into this angle the epimeron protrudes, so that at this point it approaches more to the under surface than it does elsewhere, and in many forms (especially in Eretes, Thermonectini, and Cybistrini,) the epimeron becomes visible, even when the wing-cases are closed, as an acutely angular projection at the upper and hinder angle of the apex of the episternum. Behind this point the epimeron again completely covered by the wing-case, proceeds farther backwards along the external or upper part of the hind coxa, till it terminates behind by connecting with the side of the basal segment of the abdomen or hind body; sometimes the connexion between these two parts is effected not by actual contact, but by means of an intervening membranous space (Acilius, Hydaticus, and many others, but in other cases (Hyphydrus, Eretes) there is complete contact between the horny portions of the two parts ; between the extreme degrees of separation (as seen for instance in Coptotomus) and the absolute contact of Hyphydrus and Eretes, there exist every grade of connexion ; thus in Agabus it would be almost equally correct to describe the two parts as separated by a membrane or as in contact. The upper portion of the epimeron becomes membranous, and connects with the pieces of the metanotum. In those cases where the middle coxae are widely separated, and there is no mobility of the pieces of the thorax (Hydrovatus, Hydrocanthus, Pachydrus) there is a most extreme and perfect adaptation ot the inflexed edge of the epipleura, to the side of the body, and in these cases the epimeron remains nearly entirely membranous, a mere strip of semicorneous matter, along its lower edge and its extremity, serving for the suture with the episternum On Aquatic Carnivorous Coleoptera or Dytiscidce. 233 and hind coxa, while in Eretes where there exists considerable capacity for thoracic movement, and very little adaptation of the elytra to the sides of the body, the whole of the large epimeron is horny. The more important of the characteristics of the metasternum in the Dytiscidae are, 1 , the peculiarly formed side wings ; 2, the intercoxal process grooved for the reception of the prosternal process, and 3, the absence of a transverse suture on its posterior part. None of these characters however are constant enough to serve as marks of distinction between the Dytiscidte and Carabidas ; the first of them is excessively variable in the Dytiscida ; it is chiefly dependent on the great develop- ment of the hind coxae, and in Amphizoa and Pelobius, and even in Colpius and Suphis, the form of the metasternum is quite Carabideous. The groove of the intercoxal process too is far from being constantly present in the Dytiscidse, it is absent as we have seen in all cases where the middle coxse are widely separated, and all that can be said is that it never occurs in the Carabidte, but is present in the great majority of the Dytiscidas. As regards the transverse suture in the metasternum, it occurs in the Dytiscidse only in Pelobius and Amphizoa, while on the other hand it becomes indistinct in some Carabidae, although I have not succeeded in finding any in which it is effaced. The metasternum of the Haliplides has none of the peculiarities of the Dytiscidse ; the intercoxal process is not grooved ; the outline is completely Carabideous, and the transverse suture is present, though without dissection it is not easily apjireciated owing to a series of very large punctures placed on it. The contiguity or amount of separation of the middle coxse in the carnivorous Coleoptera appears to me to be dependent rather on the metasternum than on the mesosternum. In the Carabidte these coxas are nearly ahvays very considerably separated by the intercoxal process, so that the one group of that family — the subfamily Ozsenidse — in which the coxse are unusually approximate is, according to Leconte, well distinguished by this character from all the rest of the family. In the Dytiscidse, greater variety in respect to the contiguity of the middle coxse is found, but still the character appears to me to be one of great importance ; indeed if I might exercise my imagination I would suppose that in the early history of the Dytiscidse the fact whether the middle coxse were well separated, or were approxi- mate, exercised a most important, or indeed predominant influence on the future mode of evolution. When they were distant this fact appears to me to have facilitated rapid co-adaptation of the contiguous parts for the purpose of protection and keeping out water from entering the body by the great fissure between the prothorax and the after-body by a process of mere placing together of accurately fitting surfaces ; and this involved complete disuse of any mobility or extension between these parts, and rendered sedentary habits of advantage, for in all movements there was the danger of these parts becoming separated, and it was necessary to keep the pieces of this great joint without any motion, and yet they 234 On Aquatic Carnivorotts ColeojJtera or Dytiscidce. were not locked together by auy mechanical contrivance. But ia those cases where the coxse were more approximate, the accurate adaptation of the parts at this important spot was much less easily effected owing to the more complex faces to be co-adapted ; and the locking together of the pieces was effected by the more tardy but superior process of growth of the prosternal process to rest in a groove of the metasteruum, and by the fitting together of numerous less superficial parts and edges ; this plan probably placed the original developers of it for a period at a disadvantage, but permitted ultimately a development of the parts consistent with greater general activity and with a consequent general higher organization. In the cases where the coxse are absolutely contiguous (as in Vatellini, Andex and a few others) space was wanting to permit of the penetration of the prosternal process between the middle coxa3 and so the prothorax was fixed by a short process being received into the mesosternal fork, leaving a very incomplete joint; or (as in Sternopriscus the prosternal process grew backwards under the projecting middle coxjB (instead of between the coxa;) and so only connected with the metasternum in a very imperfect manner. However this may have been, 1 believe that the distance between the middle coxse has in each species been very constant during very long periods of its evolution, and may prove of much assistance in deciding as to the relationship of particular fossils to particular existing forms. Hind Cox^. — Although tinily a part of the leg, yet the hind coxa in the Dytiscidse is developed to such an extent that it frequently forms a considerable portion of the external skeleton, and is therefore actually a part of the body rather than of the limb. It is from a taxouomical point of view, the most important part of the Dytiscidte, and its various modifications are very interesting on account of their great variety in detail and uniformit}- in more important particulars. The pair of hind coxse extend all across the under surface of the body, and thus largely separate (when an undissected individual is looked at) the hind border of the metasternum from the ventral plates of the hind body. The coxa is completely destitute of mobility, for it is soldered in front, along its entire breadth to the metasternum, while behind it is accurately fitted to the basal ventral segment, and in the Bidessini is completely soldered thereto, so that in this group we find that the whole of the middle of the lower surface of the body — from the middle legs to the end of the third ventral segment, consists of a single, solid, hard piece ; in all other Dytiscidse, however, the ventral segments are not soldered to the coxsb ; althouoh the apposition between the two parts is so perfect that they look as if they were but one, yet really great mobility exists at this articulation. Each coxa articulates with five distinct pieces of the skeleton, viz., 1, its fellow coxa, 2, the metasternum proper, 3, the metasternal episternum, 4, the metasternal epimeron, and 5 the basal ventral segment. It consists of two distinct parts, viz., 1, the lamina interior, and 2, the lamina exterior. The internal lamina it is that carries the articulation of the swimming leg, and the two internal laminae are accurately On Aquatic Carnivorous Coleojytera or Dytiscidie. 235 fitted together, and more or less strongly soldered together on the middle line of tlie body by a straight longitudinal suture ; a suture or impressed line runs near the outer border of the internal lamina, and proceeding forward, either reaches the anterior border of the coxa (as in most Agabi), or becomes obsolete in front ; in this latter case no real line of demarcation exists between the external and internal laminre in front of the part where this line stops short ; this line I call the coxal line, or speaking of the two together, coxal lines. The hinder part of the internal lamina is prominent, and presents a free edge over which the trochanter of the swimming leg plays, and which by its shape determines to some extent the kind of motion made by the swimming leg ; this is the coxal process, or coxal lobe. This process or lobe usually has, at any rate towards its termination, a kind of external margin or border, marked off by the terminal portion of the coxal line ; this is the coxal border. The hinder edge of the coxal process is very frequently marked by a short closed suture (see Dytiscus) or a small notch or emargination ; this I have called the coxal notch. The external division or lamina of the hind coxa is always larger than the other, sometimes enormously larger ; its front border proceeding from the middle is directed outwards and at the same time more or less forwards, l)ut before reaching the side, turns more or less abruptly backwards, so as to form a sort of curve or arch of very diverse forms ; it is soldered to the metasternum, but it passes outwards beyond this latter behind the posterior point of the epister- num, thus reaching the margin of the epipleura ; it does not, however, there terminate but (as is seen on taking off the wing-case) is reflexed upwards passing behind the epimeron and terminating externally, in an either angulated or rounded form, by articulation with the outside of the post-scutellum, by the intervention of a small piece considered by Schioedte (Dan. El. p. 377) to be a trochantin. The hind margin of the exterior lamina (as seen where the specimen is entire) is likewise directed somewhat towards the front, and near the epipleura forms a considerable curve or sweep, which is continued under the wing-case, to the outside extremity of the coxa ; this apparent hind margin is not however the real hind margin, for on dissection it is seen that the coxa is to a large extent reflected in a very round curve upwards to the interior of the insect ; this reflected and concealed portion of the coxa may be called its abdominal portion, and in Hyphydrus is very distinctly marked off along the whole breadth of the coxa by a raised line or margin. The -exterior lamina of the coxa differs greatly in size and shape, and its variations offer one of the best modes of distinguishing the genera and species. The changes of form occur on its anterior portion. Tlrus in Pelobius and Amphizoa where the Dytiscid coxa is seen in its most rudimentary condition, the metasterno-coxal suture proceeds directly outwards, without stretching forwards at all, so that the two sutures together form a nearly straight line extending all across the under surface : we find the other extreme in the genus Eretes, where the metasterno-coxal suture proceeds almost directly forwards, thus the sutures of the two sides at their TBAItS. BOY. DUB. SOC, N.S, VOL, n. SI 23t) On Aquatic Carnivorous Coleoptcra or DytiscidcB. point of connexion form a very acute angle, and proceeding forwards like the branches of a letter V diverge but little till they have become quite near to the middle coxa when they are rather abruptly turned outwards. In Hydrovatus these sutures of the two sides diverge from one another only at a very obtuse angle, and therefore are directed but little forwards at first, but when rather near to the out- side of the body, the direction becomes more abruptly forwards, but only to be almost immediately even more abruptly bent back : a similar form of the coxa is pretty general in the Hydroporini. The anterior border of the coxa of the Dytiscidpe thus forms in front an arch which is very various in its form, in Eretes as we have seen it is a broad, very flat arch ; while in Hydrovatus a naiTow abrupt curve placed near the outside of the body is formed. Yaiious intermediates between these extremely different forms occur ; and it is only in the Noterides that we find a really distinct form of the coxa, owing to the fact that this part attains its greatest extension forwards near to the middle of the body, and then becomes shorter towards the side. In the Cjibistrini the coxa assumes in front a shape characteristic of the group, its greatest anterior extension being gained near the outside of the body, while external to this point it so abruptly retreats as to form almost a right angle. In size tlie external lamina varies even more than it does in foi'm; it is, compared with the average of other Coleoptera, always large, and within the bounds of the family is least in Pelobius and Amjihizoa; in certain species of Agabus (Dytiscus uliginosus. No. 694, Agabus maderensis No. 666), it IS not greatly larger than in Amphizoa, and with every gradation of growth in various species and genera, reaches a truly enormous size in Hyphydi'us, Eretes^ Acilius and Coptotomus. Though the external lamina is of much interest and importance, yet the internal lamina on account of its being the seat of the articulation of the portion of the leg used for swimming is much more important, and much more complex and varied. The base of each trochanter is placed in a kind of box, and the larger the opening of the box the greater is the range of motion of the limb, and the more powerful its sweep, and in the higher forms of the Dytiscida? the articulation is constructed so as to allow the leg to make a sweep extending round the complete half circum- ference of a circle, and yet the articulation is so well constructed that no water can obtain entrance by it to the interior of the body where the muscles ai'e situated. The socket is formed above by an arched plate, which appears to be merely a prolongation of the abdominal portion of the external lamina of the coxa, and below by the coxal lobe or process, there being left between these two parts a large circularly transverse cleft looking backwards and laterally ; the internal Avail is concealed owing to its being closely connected with its fellow of the opposite side of the body ; in fact in all the higher forms of the family, there seems to be only a single opening for the two legs — in other words the two transverse clefts appear joined into one — but when a dissection is made, it is seen that they On Aquatic Carnivorous Coleoptera or Dytiscidce. 237 are separated by a vertical wall, or plate ; this wall ascends from the common suture between the two coxte, and at its termination, spreads out above into a kind of winged or bifid process which completely fills up a gap that would otherwise exist between the arched roofs of the two cavities. The articular portions of the coxa project backw^ards, and on each side of the projecting portion there is a hollow or axilla which permits the base of the swimming leg to be rotated forwards till the front edge of the femur can quite attain the longitudinal middle line of the body. In the higher and larger forms of the Dytiscidre which I am now describing, the articular cavities are entirely concealed by the coxal processes, which project from the surface more or less slightly backwards, and are thus very consjiicuous on the under surface of the body, the swimming legs protruding as it were from the hind part of the projection, and being so close together that their inner margins touch one another at the point of articulation. This structure, with modifications in some details such as the size and form of the coxal lobes, prevails throughout the Macro-Dytiscidte, without any exception. But in the smaller Dytiscidse the articulation of the swimming legs is of a different and much less uniform nature. If a Hyphydrus be looked at — and with this object one of the two swimming legs should be carefully disarticulated — it will be seen that the swimming legs do not project from behind and above any prominent coxal processes, and that they are not contiguous, but are separated by a considerable space, and if the leg has been carefully disarticulated, without damage to the articular cavity it will be seen that this is a circular orifice, completely exposed and not concealed by any projecting lobe, and a farther examination renders it evident that the space separating the articulations of the two sides of the body, consists of the coxal processes. Here then we have the articular orifice exposed and placed outside of the coxal process, separated from its fellow and circular in form, instead of being placed above the coxal process, concealed by it, and contiguous with its fellow ; on separating the hind body from the coxa it is farther seen that the upper portion* of the articular box projects further back than the coxal processes, these latter, being adpressed to, and soldered to the former : thus the coxal processes, are not prominent from the level of the base of the abdomen, and there is no axilla formed to permit the flexion of the leg forwards : indeed the articular cavity being circular and exposed permits the leg to be rotated forwards even farther and more freely than in the Macro-Dytiscidae. This is the type of structure which admits of the greatest amount of motion of rotation for the swimming leg and it attains its maximum of develop- ment in the New-World genus Pachydrus, where it is accompanied by a consolidation of the coxa with the abdominal segments. Many of the Hydroporini have the articular cavities constructed in a manner that is intermediate between that just described, and that of the Macro-Dytiscidse ; as a good instance of an intermediate * I have in my descriptions occasionally spoken of this upper portion of the articular cavity, when it is visible under the name " pyxal process." 2 1? 238 On Aquatic Carnivorous Coleoptera or Dytiscidce. condition, Hydroporus gigas No. 427 (Chostonectes) may be mentioned. In Pelobius and the Hydrovatini we have another form of articulation of ihe swimming leg -. inasmuch as the coxal cavities are rather widelj^ separated, but yet are concealed by a coxal lobe; the inner termination of the articular cavity appears therefore in these cases in the form of an opening or excision on the hind margin of the internal lamina. I have already spoken of a mark which commonly exists on the hind margin of the internal lamina, either as a slight notch or interruption of the outline of the coxal process (C^^bister, Ilybius, &c.,) or as a closed shoi't suture (Dytiscus). This coxal notch is remarkably persistent, and indeed thougli it appears to be absent in many forms (Acilius e.g.) yet on careful examination I have alwaj's found some traces of it, it exists also in the Carabidse, and is perhaps an indication that this part of the coxa is formed by the coalescence of two distinct pieces ; its persistence is at any rate very remarkable, and is clearly an indication of some formerly different structural condition of these parts. I had thought at first that the articular opening existing in Pelobius and Hydrovatini was merely an enlargement of this coxal notch but such is not the case, for in Pelobius the coxal notch may be seen existing on the coxal process, just outside the articular opening. In the Noterides the coxal lobes are of large size and peculiar form, reaching furthest backwards at their outer angle, which is thus more or less acute, they are greatly prominent from the rest of the under surface, and thus form a deep elongate axilla, while the articular cavities them- selves are completely concealed ; in respect therefore of the development of the coxal processes, and concealment of the articular cavities, the Hyphydrini and the Koterides stand as the op^josite extremes of the family. In Amphizoa the articular cavities are widely sejDarated, and are concealed, but their inner termination is distinctly visible on the hind margin of the coxal process, the coxal notch being placed immediately outside of this opening : this differs from the articulation in Pelobius, inasmuch as the termination of the articular opening is not prolonged forwards, and thus forms a shallow emargination instead of a deep excision, if we suppose the space separating the two cavities in Amphizoa to be absent, the structure would not then differ materially from what exists in the Macro-Dytiscidaj. The structure of the hind coxa in the Dytiscidse may be summed up as differing from that of the Carabidce in the following points ; 1. The large size or area of the external lamina ; 2. The arched anterior border of this part ; 3. The accurate adap- tation and soldering of the two internal laminje together by a straight and perfect suture; and 4. The contiguity of the articular cavities. As regards the first of these points, it is certain that so far as the large majority of the Dytiscida3 are concerned, the greatly increased size of the outer lamina of the hind coxa is very remarkable and is one of the modifications of structure most characteristic of the family : it is however only a question of degree, and varies extremely in the different groups, so that Amphizoa and Pelobius, in which forms it is smallest, appear rather to be Carabidaj than Dytiscidee in respect of this peculiarity : I am not aware however of On Aquatic Carnivorous Coleoptera or DytiscidcB. 239 any Carabidaj, in which the area of the external lamina of the hind coxa is anything like as large as it is even in Pelobius and Amphizoa. In Trachypach3's and Systolo- soma of the Carabidne, the hind coxa is large, but it is made so by the increase in size of the internal rather than of the external lamina. In Silphomorpha the in- ternal lamina is very small, and the external one correspondingly large, thus making a slight approximation to the Dytiscidse. [Second, As regards the arched anterior border of the hind coxa in the Dytiscidse ; such a character is I believe absolutely unknown in the Carabid£e,but unfortunately it is not always presentin the Dytiscidse, being absent in Pelobius, Amphizoa, and Colpius, and very nearly absent in Suphis. Third, The accurate coadaptation of the two internal laminae at their junction on the middle line is quite characteristic of the Dytiscidse and is always present ; it is however approximated by some Carabidse, viz., the Pseudomorphides, Trachypachys and Sj'stolosoma ; but the only one of these that really makes any near approach in this respect to the Dytiscidte is Trachypachys. Fourth, As regards the contiguity of the articular cavities, this is very conspicuous and characteristic in the Macro- Dytiscidte, but in many other Dytiscidse it is not present (Pelobius, Hydrovatini, Hyphydrini, Bidessini, Colpius), indeed a slight separation of the cavities is so common in the lower forms of the various groups, as to strongly suggest the idea that all the species of Dytiscidaj have had ancestors with separated posterior coxal cavities like the Carabidae. The Haliplides show not the least approach to tlie Dytiscidfe in the structure of the hind coxae ; on the contrary they possess a peculiar development, which is not approximated by any Carabidse or Dytiscidae, of these parts. HiND-BODY, or Abdomex. — The dorsal plates of the hind body are eight in number, and they differ but little from one another in length : they are membranous in tex- ture, but usually dark in colour ; the seventh and eighth are a little thicker than the others, and have thus a leathery consistence, and they are also dull and more or less punctate, especially the eighth, while those in front of them are shining : in Dytiscus the two basal segments bear a large quantity of very fine, elongate hair, and other genera show sometimes a similar development though to a less extent. In Hydro- vatus the dorsal plates are very thin and delicate, and pallid in colour, and the apical one differs but little from the others. The basal segment is attached to the hind margin of the metanotum, and each segment is attached by its sides, b}' the intervention of a very delicate membrane, to the harder side pieces of the body. The metathoracic stigma is placed at the hind margin of the metathorax, at the side of the body, and may be either small and inconspicuous (Cybister), or elongate in the transverse direction (Dytiscus) : there are seven pairs of true abdominal stigmata ; the first abdominal plate is without a stigma, but each of the other plates bears at the outside a stigma placed in its delicate membranous border, the stigma of the eighth or terminal segment, is usually placed quite at its front edge, but in Cybister is placed near its hind margin. The stigmata vary greatly in their size and develop- 240 On Aquatic Carnivorous Coleoj^tera or Dytiscidce. ruent and are at their maximum in Dytiscus, where all are large, and those placed on the two apical segments are, contrary to the usual rule, larger than the others, and are of a transversely elongate, elliptical form. In Cybister and Megadytes the abdominal stigmata are all small, and the quite small apical one, passes through the segment in the form of a tunnel, instead of opening directly through it as it does in others of the family ; moreover in the two genera just named, the terminal segment appears to be much more retractile and mobile than it is in other forms. The side pieces of the hind body consist of a hard membrane, becoming externally harder and corneous, and attached to the side of the turned up edge of the ventral plates ; the side piece of the basal segment is marked in the Colymbetini and Dytiscini with transverse rugse, which do not occur in any other Dytiscidse, and are probably of some assistance in the process of respiration. The ventral plates or segments, are six in number, and are hard and corneous ; they are transversely arched and each one has its outer margin turned upwards, and even somewhat inwards, and this part is marked off from the rest of the surface by a raised margin, so that the upjser edges of the ventral plates look at first sight as if they did not belong to this part of the body, but were rather the abdominal side pieces ; the margin giving them this appearance is however nothing but a raised carina for the accommodation of the edges of the elytra, a similar margin being developed, on the outside of the hind coxa and even along the side pieces of the metasternum. The basal segment is very much modified in form to accurately adapt it to the hind coxa, and for this purpose its middle appears to be completely cut away, so that in an undivided insect, the first visible ventral segment appears to be separated into two pieces placed one on each side and separated in the middle by a considerable interval ; but on dissecting off the hind body it is seen that the two pieces are connected together by a slender isthmus, but that this middle piece or isthmus is concealed by being turned upwards at right-angles to the rest of the plate. The basal segment carries on its upper face (and therefore as it were in the interior of the body) a transverse corneous partition, extending all across the hind body, and adapted to the reflexed postei'ior portion of the hind coxa ; this concealed transverse partition is the true first ventral plate, the basal plate just spoken of being really a portion of the second segment : it results from this arrangement that the first dorsal plate is attached to what is truly the second ventral plate, the second dorsal plate to the third ventral, and so on ; but this nomenclature is not in use and the first visible ventral segment or true second plate is called the first plate. The second ventral plate is more or less slightly emarginate in the middle in front, by being adapted to the projecting internal laminte of the coxfe ; in some cases this emargination is but slight (Cybister, Dytiscus) but in others Dytiscus duodecim-pus- tulatus No. 462 e.g.) it extends nearly to the hind margin of the segment, so that in such a case if the ventral plates are counted along the middle line they appear to be only four in number. The sutures between the first and second, and On Aquatic Carnivorous Coleoptera or DijtiscidcB. 241 between the second and third segments are more or less fine and indistinct, these segments being in fact soldered together and immovable, but the remaining ventral sutures are distinct, the plates being mobile : the fourth and fifth ventral plates are shorter than the others, but usually not very greatly so ; the sixth or last plate is more elongate, more or less obtusely pointed, and with its hind edge more or less finely margined — very finely in Hydroporides, coarsely in Cybister ; in Ilybius this plate shows a considerable difference of form according to the sex, but this is a rare exception. The outer or upper portion of the ventral segments, placed under the wing-cases, and marked off as I have already described by a raised carina, varies a good deal in its width, especially on the last three segments ; It is broad in Hyphoporus and in the convex forms, such as Hydrovatus, and Hydro- canthus, and it is very narrow in Dytiscus ; in the Colymbetini this upper piece of the fourth and fifth segments is much narrower than it is in the Agabini. No important or constant character can be pointed out as distinctive of the Dytiscidte in opposition to tlie Carabidre as regards either the structure or con- nexions of the hind body. In the Dytiscidre owing to the great development of the hind coxte, the abdominal segments in the middle of the body are to all ajDpearance widely separated from the metasternum, whereas in the Carabidse it is quite frequently the case that the second ventral plate of the hind body, touches in the middle of the body the point of the metasternum ; but there are numerous Carabidse in which this is not the case (see especially Pseudomorphides and Trachypachys) .; the fact is not of any importance otherwise than as indicating the constant and complete apposition and union of the two internal lamince of the coxas in the Dytiscidse. Recollecting the aquatic life of the Dytiscidte, and their very peculiar method of obtaining a supply of air, we should expect to find some notable character in the breathing orifices or stigmata. Such is not the case however, and it is only in the few species constituting the group Dytiscini, that we meet with any peculiar development of the stigmata ; while in the larger portion of the family the stigmata show no character by which they can be distinguished from those of the Carabidee. Elytra or Wing-cases. — The elytra in the Dytiscidoe play a very important part, as it is by their means that water is excluded from all the dorsal portion of the body behind the pronotum. They are always hard and never abbi'eviate, and they fit so accurately to one another along their suture, and at the sides of the body, that the insect is enabled to carry about under them in the water a supply of air for respiratory purposes. They are never soldered together at the suture as is so frequently the case in the Carabidse, and they are kept in the closed position by an extremely beautiful combination of adaptations of various parts ; they lock together at the suture by a kind of joint similar to that called a rabit by joiners : a raised line is developed on their inner face which serves as a stop for the upturned edges of the ventral plates to repose against, while the inflexed epipleura rests its edge 242 On Aquatic Carnivorous Colcoptera or iJytiscidce. ou a raised carina developed near the borders of the ventral plates and the outside of the hind coxa, and at the shoulder is received in a groove on the upper edge of tho metathoracic episternum; the base rests directly on the vei'tical mesosternum, and the sutural angle is shaped so as to fit under the edge of the raised scutellum ; by these means accurate adaptation of the wing-cases to the after body is secured, and then the hind margin of the pronotum rests on the base of the elytra, while the prothorax itself is firmly kept in its position by its prosternal process being locked in the metasternal groove ; t'lis latter part in f;\ct plays the part of the keystone of the arch. Each elytron is articulated to the mesothorax by a projection from the base of the former about half way between the suture and outer margin ; external to the articular point the front margin is turned downwards, till it reaches the humeral angle, which is usually more or less prominent and nearly rectangular ; behind the shoulder the margin continues deflexed, and persists till towards the hind part, gradually becoming narrower, it ceases altogether at some distance before the hind sutural angle ; this deflexed portion of the wing-case is called the epipleura, its lower (or inner) edge is bordered by a very fine raised margin, and its junction with the upper surface is more or less distinctly marked by a raised edge, which forms the external outline of the body (after the prothorax). The epipleura attains its maximum of development so far as this family is concerned in some species of Megadytes (Cybister costalis, e.g.) while its minimum is found in Eretes and Ccelam- bus ; and in many of the family the epipleura becomes extremely slender behind the middle (Agabus, Ilybius, &c.) In some forms of Hydroporides (Hydrovatini, Hyphidrini, Ccelambus, &c.) there is more or less conspicuously marked off at the shoulder of the e^Dipleura a triangular space, which I have called the genicular or humeral area ; this receives the knees of the front and middle legs and permits these parts to be very closely packed away when not in use. The epipleura never extends so far as the hinder sutural angle, indeed the extremities of the wing-cases always terminate as a thin edge, and thus permit of the protrusion of the hind margin of the terminal segment of the hind body ; a supply of air is obtained during life by the insect separating these two parts which are protruded at the surface of the water, and are closed when under water by accurate apposition ; the inner face oi the elytra at this apical part is frequently pubescent (Ilybius, Cybister, Dytiscus) • the terminal portion of the wing-case is frequently slightly twisted or arched (Ilybius) and sometimes also slightly truncate (Lancetes, Dytiscus) : the sutural angle varies from being about rectangular, (Dytiscus) to very acute (Hj^drocanthus). On the inner face of the wing-case near the outer margin there frequently exists a ridge parallel to the margin, this is frequently absent (Eretes) or but slightly developed (Rhantus, Acilius) : this elytral ridge is wanting on the front part of the wing-case, only commencing about the middle or behind it, and usually does not extend to the extremity, but disappears a considerable distance before that ; in On Aquatic Carnivorous Coteoptcra or Dijliscidce. 243 A-gabus however it usually extends to the apex. In Hyphydrus the elytral ridge shows a very peculiar structure ; a little in front of the extremity there is an elongate prominent tongue, which projects towards the edge of the wing-case and even a little beyond it, leaving a small space between it and the inner face of the wing-case, and into tlie deep groove so formed fits the upper portion of the ventral plate ; as the result of this the two wing-cases at the extremity are so firmly locked together, that they can only be separated by first lifting them up from the body till the extremity of the ligula is free : a similar but smaller ligula is seen in Ccelambus, and in some other genera of Hydroporini it is found in a still less perfected state. In Queda and Pachydrus the elytral ridge attains its greatest development ; it is elongate, and for nearly its whole length forms with the face of the elytron a kind of groove into which are received the edges of the vertical segments ; near its extremity it becomes more prominent and thickened, and waved in such a manner as almost to form a broad double ligula, the elytra are thus locked together in an extremely firm manner. In Pelobius there exists two structui'es of an unique character on the inner face of the wing-case ; one is a raised longitudinal band at the extremity near the suture, on each elytron ; these bands are marked with transverse strife, and are a part of an apparatus for producing sound. The second is a large protuberance near the outer margin, just in front of the middle ; this protuberance forms a cavity into which is received a horny process on the upper edge of the basal ventral segment, and like the ligula in Hyphydrus serves the purpose of very firmly locking together the two wing-cases. WixGS. — Wings are always present in the Dytiscidse, and are well developed and large, except in a very few species (Colymbetes bifarius No. 75 7 e. g.) where they are rudimentary. They are folded in a complex manner, and placed in close adaptation to the inner surface of the wing-cases, not touching the body, and thus when the elytra are more than usually diaphanous (as in many Laccophili) the veins of the wings may be slightly visible through the wing-cases, giving the latter the appearance of being marked or coloured in an unusual manner. There are two different folds to adapt them to the size of the wing-cases ; one of these is a simple lapping over of the basal portion, but the other is a very complicated longitudinal and transverse fold and is situated on the front part of the wing just beyond the middle, and is exactly similar to the corresponding fold of the wing in the Carabidi« and Cicindelidoe. The costal and subcostal nervures are close together, and form the front border of the wing, the former of them is continued to the apex of the wing, and it is by traction on this costal nervure that the wing is unfolded, as may be readily ascertained by cutting off the wing of a freshly killed specimen, and then pulling the base of this nervure with a pair of forceps ; the subcostal nervure on the other hand is continued only as far as the transverse fold (or carpa) of the wing, when it is turned backwards, so as to leave an irregular cell or stigma immediately behind the costa ; this subcostal nervure is, when TRANS. ROY. DUB. SOC, N.S., VOL. II. ^ ^ 244 On Aquatic Carnivorous Coleoptera or Dytiscidce. traction is exercised on its base, of assistance in folding the wing. The median nervure is a broad one, and runs from the base oi the wing obliquely across it towards the hind margin in such a manner as to divide it into two approximately equal parts ; it does not however extend so far as the hind margin of the wing, but its extremity is connected with the hind part of a closed, oval cell extending forwards and connecting with the carpal cell (carj^a of Lacordaire, Int. a I'Ent. 1., p. 365). The submedian vein is a double one ; its two portions starting from the base of the Aving, run nearly parallel to one another about half across the wing, and are then connected by a short oblique nervule, and then some distance behind this converge, so as to form a narrow, elongate cell, from whose point a single nervure is continued to the hind margin of the wing ; near the base of the wing the inner portion of the submedian vein sends off an elongate accessory nervule, which extends nearly or quite to the hind margin of the wing. The anal nervure is simple and descends in a gentle curve to the hind margin, and mai'ks oflF very distinctly an anal area. At the place where the wing is transversely folded, there is situated a large cell, whose hinder part is connected with the cell placed on the extremity of the median vem ; and from the outer portion of this cell are sent off some veinlets towards the apex of the wing ; the anterior of these veinlets are more or less indefinite and tend towards the front margin, the lower one of them indeed runs more or less parallel with the apical portion of the costa and reaches (or very nearly) the apex of the wing : from the lower part of the carpal cell, a curved nervule proceeds outwards to the hind margin of the wing ; the lower of the ultra-carpal nervules is connected with the submedian cell, and is short and very curved. Between the subcostal and the median veins there is a more or less distinct accessory vein which runs from near the base of the wing to the inner angle of the carpal cell. The median vein gives off about its middle a nervule which starting at first towards the inner margin of the wing, is quickly curved towards the hind margin and bifurcates before reaching it, and thus makes with the margin a triangular space in which is placed obliquely an oblong patch of pigment near the middle of the posterior edge of the wing. The inner margin of the wing at the base is bordered by a more or less distinct fine vein; the median and submedian nervures are connected near their base, by a short, some- what indefinite transverse nervule; and rarely (in Noterus) the cell on the submedian vein at the point where it approaches very closely to the flexuous vein given oft' by the median, is connected to it by a very short transverse nervule. In Dytiscus marginalis this short nervule is present, but rudimentary. The wino-s of the Dytiscidse vary a good deal in form, and also in their pigmentation : tlie wing of Pachydrus is short and broad, and very rounded at the apex, while in Cybister the apex is acuminate. The pigmentation differs much even in the same genus ; in Eretes the membrane of the wing is quite colourless, while in Hydaticus flavolineatus (No. 1024) it is suffused with a smoky On Aquatic Carnivorous Colcopte7-a or Dytiscidce. 245 pigment, and has besides lai-ge sharply defined patches of nearly black pigment. In Pelobius the basal portion of the wing is pigmented with yellow, while the outer portion is smoky. The wings of the Dytiscidse in their neuration vary very little and are extremely similar to those of the Carabidse and Cicindelidee so that no certain character can be pointed out as distinctive. Usually the anal area is larger in the Dytiscidfe than it is in the Carabidse, but in the Noterides this part is quite as small as in the Cara- bidaa. The oblong pigment mark near the middle of the hind margin appears to be wanting in the Carabidre, but is also frequently absent in the water beetles (Bidessus, Eretes). In Amphizoa the pigment mark is very largely developed, but the anal area is rather small ; in Pelobius the pigment mark is absent, and the anal area is small as in the Carabidse. I have already mentioned that in one species of the family (Colymbetes bifarius No. 757 Agabus) the wings are rudimentary : on careful examination of this species, the costal, subcostal, and median veins are found to exist, as does also the accessory vein between the subcostal and median veins, and even the flexuous adjunct to the latter ; and the pigment mark is largely developed ; the interior portion of the wing is however scarcely represented, a portion of the submedian vein is indeed present and forms the boundary of the wing, but the parts that should lie internal to this are quite undeveloped. Although the Dytiscidoe live in watei", they are only adapted for aquatic life by modifications almost confined to their external structure. As however, owing to the modifications of their legs for swimming, they are very ill adapted for walking, it is highly important to them that they should possess wings to transport them to fresh localities when, as very frequently happens, the pools of water in which they have been living dry up. That these dwellers in the water should possess highly developed wings is not therefore so peculiar as it at first sight ajjpears ; but it certainly is a remarkable fact that their wings should be so extremely similar to those of the Carabidas and Cicindelidfe. The Cicindelidee especiall}^ are verj^ rapid runners, and take very frequent short flights, opening their wings with extreme haste, to enable them to pounce on their prey ; the Dytiscidse on the other hand, only very rarely fly, their flights are then probably for long distances, and the insect only takes to flight at all with difficulty and after a laborious preparation of itself for the jiurpose ; it is then certainly a most remarkable fact that the wings in these two families should be so extremely similar. The development of an elegant pigmentation on the wings of certain species of the family (especially Hydaticus flavolineatus No. 1024) is specially worthy of the attention of those who may be engaged in considering the origination of colour in insects ; the wings in the Dytiscidse ai'e completely withdrawn from all the external influences that may be supposed to regulate the development of colour and pattern, and yet they show extreme differences in the development of pigment, and when 2 K 2 246 On Aquatic Carnivorous Coleoptera or DytiscuUe. present in a high degree this assumes the form of complex patches or patterns. The explanation of this condition will probably therefore prove to be a physiological one. The Front Legs. — The front legs in the Dytiscidge are always short, so that when the insect is moving through the water, they, as well as the middle legs, are capable of being quite packed away into the large hollow on the undersurface of the body between the metasternum and j^rosternum, except in Amphizoa whei'e the front legs are longer than in the other Dytiscidse. The coxte are more or less conical, and are most elongate in Hyphydrus, but in the Noterides they are spherical ; owing to the peculiar form of the prosternum they are very much exposed, the cavities excavated for their accommodation on the sides of the projecting middle portion of the prosternum covering only the base and inside of the cone ; the muscles pass into the coxa at the base of the cone, so that the limb is capable of very free rotation. The articulation with the trochanter is at the apex of the coxa, and takes place by means of a slender neck, permitting of a great range of motion ; the trochanter is nearly triangular in form, and its broad base is attached to the base of the femur, but the connexion between these two parts is not a firm one, and the suture is frequently quite open behind, and at the lower part even altogether yawning. In the males of the genus Hyphydrus tlie anterior trochanters are the seat of extraordinary and incomprehensible modifications of form. The femur is short, and is thickest at its point of junction with the trochanter; usually it is not cylindrical, but more or less compressed from behind backwards, but in Colpius it is very nearly cylindrical ; its upper margin is slightly curved, and its lower is more or less hollowed for the reception of the tibia, when completely flexed ; the holloAV is greatest at the knee, and there, in consequence of it, both the front and hind faces of the femur present a free edge below, but towards the base of the femur, the hollow becomes less marked, and the front sharp edge quite disappears : this hollowing of the lower surface of the femur frequently differs much in the sexes of the same species, for in the males of many of the Macro- Dytiscidte, the tibite are greatly modified in form, and the under portion of the femur is shaped in accordance with these modifications. In the Dytiscini, Cybistrini and Hydaticides, the underface of the femur usually bears one or two pencils of setse just at its junction with the trochanter; in Eretes it is fringed with long dense cilitc, and in Thermonectes it bears a few isolated, rigid setae : the upper edge bears along its posterior margin a more or less conspicuous series of setse, of various lengths and degrees of coarseness. The tibia is about the same length as, or slightly shorter than, the femur, and is articulated with it in such a manner as usually to allow of very complete approximation of the two by flexion : the tibia is rarely nearly cylindrical (Hyphydrus), but usually compressed so as to show a flat face in front, and is broader at the apex than at the knee, so that it has thus the form of a more or less elongate triangle ; the outer lower angle of On Aquatic Carnivorous Colcoptera or DytiscicUe. '2i*7 this triangle is usually broadly rounded oft"; and as the inner edge of the tibia is longer than the outer one, the apex is oblique in its direction : the articular cavity for the tarsus cannot be seen from the front, being placed always on the posterior face of the tibia, and as the result of this the extremity of the tibia in front is a more or less chisel-like, or cutting, edge ; this edge being however always fringed with cilise, seta?, or spines. The tibise are very greatly modified in form according to the sex ; in the Dytiscini, Cybistrini and Hydaticides, the tibite are dilated, and in addition a greater or less extent of the outer part of their lower face is cut away, so as to create a hollow, which permits of the rotation of the dilated tarsus when its convex upper face is turned back, or when the tibia is pressed down on the tarsus : and the sexual change in form is accompanied by modifications in other respects as will be presently mentioned. The front face of the tibia is punctate and its posterior one smooth ; the outer edge bears setae, spines, or cilise of various lengths, and degi-ees of coarseness, and the front of the inner face usually bears a dense series of extremely short cilise. The extremity of the tibia is, as already remarked, not a truncature, but an edge, owing to the lower portion of the back of the tibia being more or less cut away, so that here there is seen a smooth polished space, and in this space is placed the cavity for the articulation of the tibia ; it is usually very near the extremity and quite close to the inner angle, but when the tibia becomes much modified in form (as in the males of Cybister) the cavity may be situated nearer to the outer than to the inner margin. Usually it is a simple circular depression but in Cybister i the lips of the orifice become prolonged into a circular neck, and a similar modification, though to a less extent, occurs in other genera where the males have highly modified tarsi. The hollowed space on the back of the tibia is an adaptation to the form of the tarsus and may be called the tarsal area. This tarsal area varies in size, as the tarsus varies in its development, as may be well seen by comparing a species of Cybister where the male tarsus is of small size (No. 1122) with another where it is large (C. owas No. 1135). The tibial spurs also vary greatly, they may be two in number, but so small and inconspicuous as to be readily overlooked, this is the case in the Hydrovatini ; and indeed in the whole family Hydroporides the spurs of the front tibite remain small and in this case are inserted at the inner margin of the tibia one at its front the other at its hind edge ; that in the latter situation being longer than the other and placed a little higher up on the tibia. In the larger Dytiscidae the spurs are much more developed and conspicuous, and in the females are placed in a similar position to that they occupy in the Hydroporides, but in the males where the tibia has much changed its form the spurs are apparently much changed in their position; thus in Cybister $ the anterior sptir is placed quite at the extremity of the tibia while the posterior one is far up on the inner edge ; in Dytiscus i the anterior spur is altogether absent, and the postei'ior one is placed on the inner edge a good distance above the extremity ; 248 On Aquatic Carnivorous Coleoptcra or Dijtiscidfp. ill the males of the Hydaticides both spurs are absent on the front legs. In the Noterides the front tibias undergo a modification of form, which attains its maximum of development in Suphis, where the tibia is changed in position owing to a twisting of the leg, the front face being turned outwards ; the anterior spur is developed into a thick, elongate, very curved, acuminate process, and being apparently soldered to the tibia gives rise to the appearance of a hooked tibia : the tarsus is inserted on the inner (now the lower) edge of the tibia just under a large prominence. In other members of the Noterides modifications similar to this may be traced, the most constant feature being the large curved anterior (or lower) spur; the structure of the primitive Noteride tibia still exists in Pronoterus, where we find a short very broad triangular tibia, with a rather small strongly curved spur at its inner angle. A very highly modified front tibia is found in the male of Eretes, where it is formed so as to allow of a maximum of rotatory motion over the tarsus when this is firmly fixed. The anterior tarsi of the Dytiscidfe belong to three quite distinct types ; in one of these they are five-jointed, the joints being more or less cylindrical and armed beneath with spines, between which the surface is shining and polished ; the four basal joints differing little inter se in length, the fifth more elongate ; this structure is however greatly obscured in the males as these in many species have the three basal joints dilated, sometimes enormously dilated, and clothed beneath with peculiar hairs or cups ; the number of joints is however always distinctly five : the Laccophilini, Amphizoa, Colymbetides, Dytiscini, Hydaticides, and Cybistrini possess tarsi of this structure, which is in fact, except as regards the extreme development in the males, that which exists in the Carabidte. The second type of structure of the front tarsi is likewise a pentamerous or five-jointed one, and the tarsi are spinose beneath, but they have the basal joint ver}'' much larger than the others, and greatly comj^ressed laterally, that is to say the joint is very deep from its upper surface to the sole, this latter being narrow ; this form of tarsus is peculiar to the Noterides ; the male tarsi though often a good deal larger than those of the female, are never highlj- modified, and they have only a very few cups on their under surface. The third form of tarsus exhibits only four joints, and of these the basal three are very different from the terminal one, being more or less broad and flat so as to present beneath a flat sole, wdiich is without spines but bears a dense spongy pubescence, the third joint is more or less deeply emarginate or bilobed, while the fourth or terminal joint is slender and cylindrical ; the male feet are not greatly different from those of the female, although frequently a good deal broader. This form of tarsus is found in the Hydroporides and Yatellini, and is not only in respect of the number of joints a tetramerous tarsus, but is essentially as regards both the form and clothing of the joints similar to what exists in the Tetramerous or Phytophagous (as opposed to the Carnivorous) Coleoptera. The modifications shown in the structure and development of the male tarsi in 0)1 Aquatic Carnivorous Coleoptera or DytiscidcB. 249 the Dytiscidse with five -jointed front feet are very interesting : in some of the Agabini tlie male front feet difter but little from those of the female, being always however something larger and more powerful owing to an increase in the bulk of the three basal joints, which moreover bear beneath a peculiar pubescence, having a sugary or glandular ajDpearance owing to the extremities of the hairs being peculiarly formed. In the Colymbetini there is usually a superior development of the male front feet to what we find in the Agabini ; the basal joints being more dilated and some at any rate of the hairs on their under surface furnished with hairs bearing paper-like expansions or cups, sometimes arranged in transverse series (Colymbetes). It is however in the Dytlscini, Hydaticides, and Cybistrini, that we find a truly wonderful development of the male tarsi ; in these groups, the three basal joints are not only enormously dilated, but are also accurately co-adapted with one another, so as to form a large circular (or transversely elliptical in Cy bister) disc or plate, the under surface of which bears larger or smaller stalked cups or palettes, and sometimes also fine pubescence, while the edges of the plate are regularly fringed with spines or densely placed fringing hairs. The hio-hest development is found in Dytiscus, Acihus, Cybister and Megadytes, where there are present on the under surface both fine hairs and very highly developed palettes. These remarkably constructed feet are powerful organs of adhesion to smooth surfaces and I believe also are highly developed sensitive organs. The claws of the front feet vary much, they are usually little developed in the Hydroporides, and are very delicate in Hyphydrus ; in the Macro-Dytiscidse on the other hand the front claws are always large, and are frequently remarkably constructed in the males, especially in the tribe Colymbetides. Deformity of the dilated tarsi of the males seems to be of frequent occurrence, I have observed it in several species of such different genera as Deronectes, Ao-abus, and Dytiscus. The Middle Legs are usually similar to, or differ comparatively slightly from the front ones, but their coxee are generally shorter and less conical, and the peculiar developments in the male sex are much less extraordinary. The coxse are usually deeply embedded in their cavities, and are then always nearly globose, and this is invariably the case when they are well separated from one another ; when however they are nearly contiguous they become more or less elongate and conical, and project from their cavities, as is especially the case in the Vatellini and Sternopriscus. The tx'ochanters and femora are very similar to those of the front legs, but nre not the seat of such great modifications in the male sex. The tibiae too are usually similar to the front ones, but often are slightly more slender and elongate ; their outer edo-e is always set with long cilise, and the front face in the Macro-Dytiscidte is nearly always roughened by bearing longer or shorter spines, the apex is always furnished with two spurs placed near one another at the inner margin : the extremity of the tibia is truncate nearly at right angles to its axis, and the edges of the truncature 250 On Aquatic Carnivorous Coleoptera or Dytiscidce. are set with spines of variable length, but which are absent from the hinder part ot the truncature. The tarsi also agree usually in structure with those of the front feet, except that they are less modified in the males ; the number of joints is the same as on the fi-ont feet ; where the middle tarsi are dilated (in the male sex of the Macro-Dytiscidte), the dilatation does not go to such a great extent, so that the three basal joints do not assume a disc-like form, but are always elongate ; they may be furnished beneath with a peculiar clothing of hairs or cups, but these are less developed than on the front feet : the claws are frequently elongate ; in the males of some species of Cybister there is a peculiar patch of hair on the under surface of the basal joint in the males, and in Homceodytes a similar peculiarity is found on the third joint. The remarkable Australian genus Sternopriscus differs from other Dytiscidce inasmuch as the males have the middle legs very much more modified than the front ones are. Hind or Swimming Legs. — The posterior pair of legs in the Dytiscidte are used only for aquatic locomotion, and are profoundly modified in accordance with their unusual function : no part of the structure of these water-beetles however varies so much as do the swimming legs ; the difterence between their feeble, and nearly useless condition in Hydrovatus and Methles, and their powerful and complex development in Cybister and Megadytes and their allies, being enormous ; in fact so great is the variety in the development and details of structure of these parts, that a very large proportion of the species of the family could be distinguished from other species by the swimming leg alone. An examination of this organ, and a comparison of it with the leg of a Cai'abid are sufficient to make it evident that the latter might possibl}' be modified so as to form the swimming leg of a Dytiscid ; while the study of the details of structure of the part in this latter family reveals so many cases in Avhich remnants of a Carabideous structure still exist as to make us believe that the swimming leg of the Dytiscidie may have previously been a leg for running like that of the Carabidas. The metamorphosis consists in an increase in the transverse dimensions of the pieces, and in a compression or flattening of them, so that one aspect of the limb presents a large surface, while another is reduced to a mere edge : at the same time there is a large growth of elongate cilia; or swimming hairs, which are very readily spread out to form a very large surface to be opposed to the water, and just as easily depressed so as to offer no resistance whatever to the return of the leg to a position for making a fresh stroke. The most powerful swimming leg exists in the Cybistrmi, the feeblest in Hydrovatini, and Suphisini, Pelobius and Amphizoa, and CeUna and Methles. The coxa has already been described in speaking of the under part of the body (page 234). The trochanter is never very large, and is usually, closely aj^ijlied to the base of the femur, so that the two almost appear to form one piece ; it does not vary greatly in size, and is not the seat of any remarkable developments, but is large and more globose and inflated in the Vatellini, while in the larger Dytiscidae On Aquatic Carnivorous Coleoptera or Dytiscidcp. 251 its apex becomes even very acute (Cy bister). The femur is short, rarely so long as to project at the sides beyond the edge of the wing-case, but it does so in Vatellini, Amphizoa and those species of Agabus at the commencement of the genus, and even in some of the species of Deronectes : it is more or less compressed or flattened so that it is elongate from front to hind edge, very short in the vertical direction, but in the lower forms it is much nearer to cylindrical in shape ; at the base its hind portion is cut away to admit the trochanter, to which the femur is attached only by a small piece at its base ; although frequently (especially in the Hydroporides and Cybistrini) the trochanter is very closely applied to the excava- tion in the femur, yet in other cases (Dytiscus) the fitting between the two is very imperfect. The front of the femur forms a sharp edge in the highly evoluted forms, but is blunter in the lower ones, where the femur is less blade-like, (Pelobius, Amphizoa, and Hydrovatini, &c.) ; its upper face is flat, smooth, but with a few "wrinkles, and in Pelobius with an obsolete series of distant punctures placed parallel with its hind margin, in Hydaticus with a closely placed series of setiger- ous punctures, and in Eretes with a band of densely placed fine cilipe ; quite in front it usually bears a series of very short seta3 or spines, which usually become longer on the basal portion ; from base to apex the femur is slightly curved, so that in this direction the upper face is a little hollowed, which permits it to be extended in the forward direction along the curved surface of the breast, with which it comes in close contact at the point of its greatest flexion ; the lower or free surface, is smooth in the higher forms, more or less roughened in the lower forms ; just where it is rounded oft' in front at the knee, there are frequently some coarse punctures bearing short thick spines (Dytiscus) ; sometimes a series of distant punctures each bearing a seta is placed along the lower face of the femur parallel with its hind margin (Noterides) ; and the hind margin itself bears in the Noterides a regular group of elongate setse, placed at the knee, and which attain a very remarkable development in Hydrocanthus ; in the Colymbetini and Dytiscini there is usually some punctures forming an indefinite group, at the outer extremity of the femur, and in Agabus there is a group of setse arranged in a short row near the hind margin at the outer extremity, which varymuch in their development according to the species. The posterior face of the femur is more or less hollowed for the reception of the tibia when this latter is flexed ; this hollow does not extend to the base, (where indeed the hind face of the femur is almost an edge), but is confined to a greater or smaller area at the extremity ; this hollow causes the upper and lower faces of the femur to terminate each as an edge, or lamina, of which the lower one is larger and projects farther back than the upper; the angle at the knee of the upper plate is always rounded, that on the lower plate frequently rounded, but in the higher forms more or less acute : in the lower forms of the family where the swimming legs are of inferior structure, these laminse are scarcely to be detected : in the higher Noterides, the lower lamina is excessively developed. TKANS. ROY. DUB. SOC, N.S. VOL. U. 2 1" 252 On Aquatic Carnivorous Coleoptcra or Dijtiscidce. The liind tibia is in the Noterides alone so long as or a little longer than the femur, but is sometimes much shorter (Cybister) ; this part varies extremely in its development ; in the feeble swimmers (Hydro vatini, &c.,) it is elongate, many times longer than broad, and increases very slightly in diameter from the knee to the extremity, a transverse section being nearly cylindric ; in the higher forms, the tibia is much broader, and thousrh when dissected off it is found to be always narrow at the knee, yet it attains its great breadth almost immediately below this, so that in Cybister, the articular cavity is situated on an exti-emely short neck placed at the anterior and outer extremity of the tibia; the tact that the greatest breadth of the tibia is gained immediately at the knee is characteristic of the Cybistrini, and the higher Hydaticides ; in the Dytiscini and Colymbetides, this abrupt spreading out of the tibia immediately at the knee does not occur, but the tibia increases in breadth by a gentle curve on its inner edge behind the knee, and gains speedily its greatest width near to the base, thence continues nearly parallel sided to the extremity, or indeed slightly diminishes in width towards the apex owing to a slight curving inwards of its outer margin. In Bidessus and Sternopriscus, the tibia is of peculiar form, being a little crooked owing to its being bent a little outwards some distance below the knee, and a slight bending outwards of the tibia likewise exists in many Hydro2Dorides, especially in Ccelambus. Usually three faces are well defined on the tibia, viz. an upper, a lower, and an inner one, but in Cybister where the metamorphosis of the tibia is extreme, the inner face has entirely disappeared at the base, and is only tolerably well defined at the apex, so that the tibia in such case forms a flattened upper face, and a curved or slightly arched lower face ; and in Hydrocanthus the tibite are so flattened that they form a plate whose two faces are only very slightly arched ; the lower face of the tibia shows a varied sculpture, being sometimes polished and with only a series of punctures placed near its outer edge (Noterides), sometimes dull and with a dense series of sette running its whole length parallel with the outer edge (Vatellini and many Hydroporini) sometimes densely punctate (Deronectes, group 1); but more usually the interior portion of the face is smooth and polished, while the exterior portion has large punctures bearing spines, (Cybister and many Colymbetides), while in other cases these large punctures have to a great extent disappeared but leave a marginal series along the outer margin; the outer and inner edges of the lower face of the tibia are armed with a series of spines. The upper face of the tibia bears, quite at the outer edge, elongate fine cilire or swimming hairs, which however are almost absent in Hydrovatus and Methles ; its surface is, like the lower one, either polished or dull, but bears some large punctures furnished with spines, which assume a very remarkable development in the higher forms ; the usual arrangement of these spine-bearing punctures is that there is a longitudinal series parallel with the outer margin, while the rest of the face external to this series may be quite smooth (Ilybius) or bearing numerous large, irregularly On Aquatic Carnivorous Coleojitera or Dytiscidce. 253 placed punctures armed with short acuminate spines (Hyderodes) ; in Dytiscus the surface is smooth with an irregular double row of large punctures arranged alono- its middle and each bearing a rather elongate spine, with a peculiar flattened and bifid extremity ; in Hydaticus there is a single series of such spines along the middle, and in Thermonectes this series becomes oblique in direction and the punctures approximated ; this is also the case in Acilius where moreover the peculiar spines become very elongate, and in Eretes this peculiar oblique series is much more developed and placed near the apex of the tibia ; in Cybisterthese peculiar long spines with bifid extremities form a dense tuft placed at the hinder outer angle of the upper face of the tibia, the rest of the surface towards the base bearing also scattered short spines ; the series of developments exhibited by these spines, and their culmination in the highest forms indicate that they have some functional importance, though it is difficult to imagine what this may be. The inner edge of the upper face beai's a series of sj)ines, and the outer edge is fringed with dense elongate swimming hairs. The inner face of the hind tibia is without sculpture, and its inferior margin bears elongate swimming hairs, which however are sometimes very scanty and are never so largely developed as the swimming hairs on the outer side of the tibia ; as before remarked, in Cybister this inner aspect of the tibia is only indefinitely distinguished from the upper face, while in the Noterides it is nearly absent, owing to the com- pression or flattening of the limb. The apex of the tibia is fringed densely with spines of variable lengths, and degrees of regularity, and bears two spurs which ai-e always largely developed, and are placed on the inner side one at the upper, one at the lower angle : in proportion as the swimming legs become largely developed so do thesq spurs become remarkable, so that in Cybister they are about so long as the tibia itself : they become bifid at the extremity in Laccophilus, and the Thermonectini; in the Cybistrini the lower of these spurs becomes broad and flattened, while the upper one is canaliculate along its lower aspect, and in Megadytes is frequently bifid or even trifid at the apex; it is probable that the dilated lower sj)ur in Cybistrini gives support and strength to the tarsus, and it is rendered additionally useful for this purpose, by being itself supported by a prolongation backwards of the lower face of the tibia immediately below this spur. The tarsus, like the other parts of the swimming leg, is the seat of great variation in its development ; in the higher species it has undergone a great change by which it is well adapted to serve its purpose as a means of locomotion in water but in the lower forms, Hydrovatus, Celina and Methles, and more especially in the last two, little or nothing can be pointed out to distinguish it from the tarsus of the Carabidse. It is invariably five jointed and does not, as do the other feet, ever show any diminution of the number of its joints. In the higher forms, it has undergone a process of lateral compression so that it is flattened and presents only two faces, the joints are accurately coadapted in form and rigidly fixed together, even the claws become straight and rigid ; and at the same time it is 2 L 2 254 On Aquatic Carnivorous Colcoptera or Dytiscidce. so articulated that it undergoes a process of semirotation when moved through the water, as the result of which when acting as a propeller it presents a broad face to the water, but when it is jsassive or is moved through the water for the purpose of attaining a position from which to commence another stroke it presents an edge ; in other words, what rowers call feathering the oar is performed by the tarsus of the Dytiscidse in a most perfect manner. Both the true upper, and the true lower, surfaces of the tarsus are mere edges, and the former bears elongate swimming hairs, which are depressed Avhen the limb is at rest or moving forwards, but are spread out when the foot is acting as a propeller ; the latter or lower edge being closely set with spines. In Pelobius, however, the sole of the tarsus still exists as it does in the Carabidse ; that is to say the lower face of the foot bears two series of spines and between these series a considerable space intervenes. It is an interesting fact that in many of the higher Dytiscidte there are remnants of this structure still to be seen in the highly changed tarsus ; the sole it would seem, disappears, at any rate in some cases, not by any diminution or degeneration but by a process of growth of the tarsus and concomitant modification of form by means of which the sole becomes j^art of the inner face ; in other words the inner face of the tarsus in the higher Dytiscidse is homologous with both the inner and lower faces of the tarsus of Carabidfe. In the Carabidse the tarsus has two sides curving into one another so that an arch forms the upper portion of the tarsus, and a sole, this latter being bounded on each side by a series of spines. In Pelobius the two sides of the Carabid tarsus and the sole still exist, as in the Carabidse, but form a triangle, of which the outer face is the longest side, and the true inner face of the tarsus is quite narrow, not so broad in fact as the sole, which is still marked off by a series of spines extending the whole length of the foot; in Dytiscus Sturmi (Agabus No. 737) where the tarsus is thoroughly Dytiscideous in form, there may be seen on the inner face of the basal joint a series of three or four spine bearing punctures, placed at a distance from the edge and evidently representing a remnant of the series of spines which serves as the inner boundary of the sole in Pelobius and the Carabidte ; in Scutopterus there is a similar series of punctures on the first and second joints ; and in the interesting Australian genus Hyderodes, this series of spine-bearing punctures actually still exists along the whole length of the four basal joints of the tarsus, on its inner face. Besides these sjaines which exist occasionally, there are on the inner side of the tarsus, other spines more constantly present ; these consist of three or four spines placed on the hind margin of each joint, near the lower edge, and of some others similarly placed close to the upper margin ; in Cybister the lower of these series of spines is reduced to a pair placed on each of the second, third and fourth joints ; in Laccophilus this series is entirely absent, and the upper series consists of a pair of suberect spines, on the first, second and third joints, one of which being much longer tlian the other, projects beyond the lower margin so that its On Aquatic Carnivorous Coleoptera or Dj/tiscidce. 255 extremity is conspicuous even when the tarsus is looked at from the outside ; quite close to the lower edge theie are irequently placed some swimmino- hairs, which however, are sometimes present only in the male (most Cybistrini, Agabus), &c. ; in the Hydaticides, Laccoj^hilus and a few species of Cy bister they are present in both sexes, but are never quite so developed as those on tlie opposite edge of the tarsus. The outer face of the tarsus is that which is usually turned upwards ; its outer margin (forming the true lower edge of the tarsus) is densely set with more or less elongate stout spines, and these are continued for a little way round the corner of each joint along its hind margin. In the Hydaticides the hind portions of each joint are fringed with densely set, adpressed ciJiae which laji over the face of the following joint, and which exist also on the inner face of the tarsus ; and in Eretes the outer and innei- faces of the tarsal joints bear shallow punctures, each of which is filled with a transparent, adpressed cilia or scale : except for these peculiarities the outer face is bare and polished. The joints of the hind tarsus are, in the higher forms such as Cybister and the Hydaticides, shaped so that they shall form together a compact piece to press against the water ; each joint is about the same width at the base as the extremity of that preceding it, and the hind margins are the most prominent part of the joint so that ^the base of each joint is received into the concave extremity of that preceding it : and thus both edges of the tarsus show a continuous or little broken outline ; it is the rule however that the outer (or lower) edge of the tarsus is (as is the case in the Carabidfe) much more broken and interrupted in its outline than is the opposite edge ; and in the genus Methles the tarsal joints are as loosely articulated and the tarsus as discontinuous in outline as in the Carabidse. In Laccophilus the tarsal joints are peculiarly shaped, inasmuch as the lower part of each joint is- more elongate than the upper part, and so projects backwards over the following joint, so that when the foot is looked at from the outside the joints have a peculiar lobed apjjearance ; a somewhat similar formation is found in the genus Ilybius, and in the group Colymbetini there is frequently a greater or less prolongation backwards of the hind margin of the lower part of each joint; by this structure the tarsus is strengthened so as to offer a greater resistance when used as a pi'opeller. The claws of the hind tarsus are very variable in their condition ; in the lower forms the}'- are two in number, equal in size, curved, small and moveable, and the under surface of the apex of the last tarsal joint has a distinct triangular excision for the accommodation of each claw. In proportion to the change and development of the tarsus so do the claws become altered, till in Cybister we find the foot terminated by a single, stout, straight, acuminate, fixed spine which has lost all resemblance to a claw, and for whose accommodation there is a large triangular excision in the material of the under (inner) face of the hind margin of the last tarsal joint. Between these extremes of development there exist numerous transition 256 Cn Aquatic Carnivorous Coleoptcra or Dytiscidce. torms, and considerable variations in the details. Looking at these stages we find that as the tarsus becomes compressed laterally the two claws necessarily become approximated, and as the sole of the tarsus changes its direction to become a part of the inner face of the tarsus, so does one of the claws get drawn above the other, till ultimately the two claws instead of being placed side by side are situated one over the other, the inner claw becoming the upper one ; this inner claw which thus changes its position, at the same time enlarges, and becomes straighter, so that the two claws may be very unequal in size, it being always the upper or inner one that is the larger ; this condition may be seen in the Hydaticides : the lower claw is frequently more curved than the upper one, or in other woi'ds retains to a greater extent its primitive form ; and frequently there is a considerable difference in this respect in the sexes of one species (Ilybius, many species). The most changed claws are found in Hyphydrus, Laccophilus and Cybister, in all of which the lower claw has disappeared, and the upper one is straight (or nearly so) and immobile. In the genus Megadytes the two claws are present in very different degrees of development in the sexes of the same species ; and it has been supposed that the two claws are not really two but are a divided or split single claw, and this statement has been repeated by some of the best entomologists ; there is, however, no ground for the assertion, which is based on the supposition that the single claw of the allied genus Cybister really consists of the two claws consolidated into one ; a careful examination, however, of a series of species shows that this is not the case, but that in Cybister, where there is only one claw present, this is because the second claw is undeveloped or atrophied. On the single claw of Cybister there exists a longitudinal channel, looking something like a consolidated suture, and this has been cited as a proof that this single claw is a united double one ; as, however, where there are two claws present (in Megadytes), each of them presents this channel very distinctly, it is quite clear that it is no indication of the claw possessing it being a double one, for if so Megadytes has really four claws. The relative length ot the joints of the hind tarsus is rather constant in the family, the rule being that the basal joint is distinctly longer than the second and that the third and foui'th are each a little shorter than its predecessor, the fifth being again more elongate, so as to equal or surpass in length the basal joint, but in Hyphydrus the terminal joint is shorter than usual. In the Noterides, however, these proportions do not hold good, and the basal joint of the tarsus is nearly or quite as long as the four following joints together. It is worthy of remark that in the Noterides the tarsus does not, as in the other Dytiscidse, develope, ■pari jxissu, with the other parts of the swimming leg, but evidently is of less functional importance, so that in Hydrocanthus we find that whereas the femur and tibia are more highly metamorphosed than in any other Dytiscidte, the tarsus on the contrary remains small, and can be of comparatively little use as a propeller. In Pelobius the legs are, as regards their structure, but On Aquatic Carnivorous Coleopfera or Dijtiscid(p. 257 little adapted for swimming orgacs, but both the iuner and outer margins ot the tibiae and tarsi are abundantlj'- provided with swimming hairs. In Amphizoa the hind legs are remarkable, inasmuch as they are completely destitute of ciliee or setse, and are elongate and slender, and not at all modified for swimming. Although the swimming legs of the Dytiscidse in the higher forms are so remark- able and characteristic, yet there is not one of their many peculiarities sufficiently constant to serve as a character by which the family may be distinguished from the Carabidse : it is in fact only in the coxa that any peculiarity of structure can be pointed out as capable of serving as a test-mark for the family. It is true if Amphizoa were excluded from the Dytiscidte, that we might define the family as possessing posterior tibipe provided with elongate cilice ; but then many species of Scarites in the Carabidre have the same parts quite as densely ciliate as have tha Dytiscidse ; Avhile if we try and seek for a character in any of the changes ot form and size of the various parts of the leg below the coxa, w'e find these to be so extremely variable as to be incapable of exact definition ; and if we descend to the feebler forms of swimming leg, and compare the leg of a Methles ia the Dytiscidse with that of a Trachypachys, or of other Carabidte, we find it impossible to discover any difference of importance in the shape and form of the various parts. The phrase " pedes natatorii" or " legs natatorial" commonly used as the definition of the family, is valueless for the purpose of a truly scientific taxonomy, although useful in conveying a vague general impression, as to one ot the most marked peculiarities of the family as a whole. III. — The Morphological Specific Chabacters. THE FAMILY DYTISCID^.* The Dytiscidse are beetles, having the antennae eleven jointed, glabrous, and shining, entirely destitute of exserted sette or sensitive pubescence, and inserted on the inflexed margin of the side of the epicranium, very close to the eye, and quite close to the upper portion of the base of the mandible. The maxillae provided with two elongate free lobes, the inner acuminate and curved at the extremity, ciliate or spinose along a portion of its inner margin, the outer slender, curved and palj^iform, divided into two pieces by a transverse suture in all the species except those of the genus Amphizoa. The presternum forming in the middle, behind, a process which jarojects horizontally backwards, behind the front legs, towards the metasternum. The hind coxse of large size, intimately soldered with, and appearing part of the * The abbreviated systematic characters in this part of the work are intended merely to serve as a guide in the search for particular species, and do not of themselves give a correct idea of the classification adopted. Tlie definition of the family should form a part of the fifth synthesis, but is placed here for the convenience of those who have no knowledse as to what constitutes a member of the faniilv. 25 S On Aquatic Carnivorous Coleoptcra or Dytiscida. metasternum, and actually forming a considerable portion of the part of the skeleton placed between the middle and hind legs, extending at the sides so as always to reach the martrin of the wingf-case when this is closed : the inner portions of the two coxaj, connected accurately together along the mesial line of the body by a straight suture of considerable length, so that the middle of the base of the abdomen (or hind body) is largely separated from the true extremity of the metasternum. The posterior legs modified for swimming, though in an extremely variable degree, by the ciliation of the tibioe and tarsi with elongate, depressable, swimming hairs, and by a compression of the femora, tibire and tarsi, by which these parts become less cylindric, but broader and flatter. Posterior tarsi always five-jointed ; the anterior and middle ones either four, or five-jointed. The family as known to me comprises nearly twelve hundred species, arranged in two series, viz. : — Series I. — Dytisci Fragmentati. Metathoracic episternum not reaching the middle coxal cavity; {vide below). Series II. — Dytisci Complicati [vide p. 317). Metathoracic episternum reaching to the middle coxal cavity. IV. I. — Dytisci Fragmentati. The episternum of the metathorax does not penetrate so far towards the middle of the body as to reach the middle coxal cavity, but is separated therefrom by a process of the mesothoracic epimeron which articulates with the side wing of the metasternum. Four divisions of very different values, and very distinct inter se can be distin- guished as follows. Metasternum quite straiglit iu the~\ middle behind, and with a dis- I Drr/^DTTT-cr / •? n^n\ ^. , , ' , , . yPELOBIvS (vide p. 2o9). tmct transverse suture marking I \ l / off a supplemental y piece. ) Metasternum more or less pointed ) in the midtUe behind, and not VNOTEEIDES (i-iWe p. 2G0). marked by a transverse suture. j ' Prostemal process not reaching the ) -TT- . ,,,, , ., „„.-.. . . ^ f- V ATELLiKi (vide p. 282). metastemimi. J \ l / L-nal process reaching the me- ) t / • ? n^^^ ^ ^ " > Laccophilini (vide p. 286).* •mum. ) \ I / * In this group the metathoracic episternum very nearly reaches the middle coxa, while in the other components of the series it is widely separated thei'efrom. Greatest anterior extension of the hind coxa is near the middle (longitudinally) of the body. Greatest anterior extension of the hind coxa is nearer to the epipleura than to the mesial line of the body Proster tastemum, On Aquatic Carnivorous Coleoptera or Di/tiscidce. 259 I. I.— Genns PELOBIUS. Posterior coxse separated from the metasternum by a suture which extends directly outwards, not at all forwards ; metasternum in the middle behind with a piece marked off by a distinct suture ; swimming legs slender, but with long cilise, their tarsi elongate and slender ; prosternal process, elongate, bluntly acuminate at the tip. This genus comprises only three species, one of them European, the others Australian ; the European species, has the scutellum quite exposed, but in those from Australia this part is nearly covered by a prolongation of the base of the prothorax. 1. Dytiscus tardus, Herbst. Hyclrachna tarda, M.C.* — Convexus, sine pubescentia fere opacus, ferrugineus, capite utrinque, prothoraceque anterius et posterius nigricantibus, elytris fuscis, marginibus irregulariter late dilutioribus, corpora subtus ex parte nigro, antennis pedibusque testaceis : prothorace basi et apice elytrisque punctato-rugulosis ; corpore subtus dense subtilissime punctato. Long. 10, lat. 6 m.m. The male has the three basal joints of the front and middle tarsi a good deal dilated, and furnished on the under side with tomentum, the dilated joints are a good deal compressed at the sides. Central and Southern Europe, Corsica and Algeria ; common in isolated spots. Not found in Scotland, Denmark, Finland or Scandinavia. 235. f 2. Pelobius australasise, Clark. Ilydrachna Australasice, M.C. — Convexus, sine pubescentia, sat nitidus, niger, thorace, elytris, antennis pedibusque ferrugineis; prothorace dense subtiliter, asqualiter punctato, elytris dense subtiliterque punctato- rugulosis ; corpore subtus fortiter punctato. Long. 10, lat. 6 m.m. In the male the basal joints of the front and middle tarsi are slightly dilated and are furnished beneath with tomentum, Australia, (Melbourne). 23G. The two Australians differ from D. tardus, by the small scutellum and obsolete frontal suture. *The name followed by the letters M.C. is that under which the species is recorded in the Munich Catalogue of Coleoptera (Catalogus Coleopterorum, autoribus Dr. Gemminger et B. de Harold, Tom. II. Monachii, 1868). Such specific names as are not recorded in the Munich Catalogue will be accompanied by a reference to the actual work in which the original description appeared. Both these references are a-bsent in the case of species here named and characterised for the first time. I The number placed in this position is that which I have used for labelling specimens and collections submitted to me for determination during the progress of the work. It may therefore be quite disregarded except by those who have from me specimens bearing these numbers. 2 M TBANS. HOT. DUB. SOC, N.S. VOL. II. 2G0 On Aquatic Carnicorous Coleoptera or Dytiscidce. 3. Pelobius niger, Clark. Ilydrachna nujva, M.C — Convexus, sine pubescentia, sat nitidus niger, antennis pedibusque ferrugineis, prothorace dense fortiter punctato ; elytris crebre punctatis, basi rugosis ; corporc subtus fortiter punctate. Long. 9, lat. 55 m.m. I have seen only females of this species. Australia, (Queensland). 237. III. 1.— Tribe NOTERIDES. Scutellum quite invisible ; internal lamina of posterior coxa very differentiated from the exterior lamina, the two separated by a nearly longitudinally straight demarcation which extends the whole length of the coxa : the anterior border of the hind coxa gains its nearest approach to the middle coxa before it has extended in the lateral direction half way towards the epipleura : Front and middle tarsi conspicuously five-jointed. Anterior tibia frequently with a hook or curved spur at the extremity. ( Note. — In Notomicrus theanterior border of the hind coxa cannot be made out, the suture between it and tlie metasternum being quite obliterated, but the peculiar form of the internal lamina cannot be mistaken.) Coxo-metasternal suture obliterated ; hind ] coxal cavities little separated; no coxal ,■ NOTOMICRUS (vide helovf). W I— I w H O line or border. i § g 8 u 2 '-3 to ' ^ C3 C i p O K. «3 o g 2 Hind coxal cavities much separated ; coxal | hYDROCOPTUS (vide p. 2G1). line and border present, although line. j \ i / Prosternal process rounded behind; hind 1 -^ - i .■ ? 9r'?\ femora without angular ciliie. j ' ^ i • ~ /• Prosternal process truncate behind; hind ] femora with angular cili;i? ; hind coxal > cavities separate. SuPiiisiNi (viile p. 267). Prosternal process truncate behind ; hind 1 femora with angular cilise ; hind coxal HYDROCANTnisi (vtrfe p. 268). cavities contiguous. j I. 2.— Genus NOTOMICRUS. Anterior tibia destitute of a curved spur, and with iuduBnite outer apical angle; posterior coxal cavities but little separated, coxal notch scarcely visible. The extremely minute species are found in Australia and South America. 4. Notomicrus loBvigatus, n. sp. — Ovalis, ;ingustulus, subdepressus, per-nitidus, Ifevigatus, impunctatus, testaceus, pectore abdominisque basi fuscis ; tarsis posterior- ibus filiformibus, tibiis longioribus. Long. \\, lat. I m.m. I see no sexual differences in the few specimens I have seen of this minute beetle. Australia, (Rockhampton, Brisbane). 4G8. On Aquatic Carnivorous CoJeoptcra or Dytisddo'. 261 5. Notomicrus suturalis, n. sp.— Oralis, angustulus, pernitidus, Itevigatus, livide testaceus, pectore abdominisque basifiiscis; elytris serie suturali punctorum sub- obsoleta ; tarsis posterioribus filiformibns, tibiis longioiibus. Long. If, lat I. m.tn. This insect is very lilje the preceding one but has an indistinct series of puncture>s along the suture of the elytra. Australia, (Rockliamptoii). 469. 6. Notomicrus brevicornis, n. sp. — Ovalis, subdepressus, pernitidus, Isevigatus impunctatus, capite, elytrorum basi, pectore abdomineque obscurioribus ; tarsis posterioribus debilibus. Long, ll, lat. f m.m. I have seen only five individuals of this minute insect, and see no sexual differ- ences among them ; it is the smallest of the Dytiscidre, and is indeed amono-st the most minute of the Coleoptera as it attains only the size of the larger Trichoptery- gidse. Brazil, (Boa Sorta, No\t. 1850, Dr. Sahlbei-g). 470. 7. Notomicrus traili, n.sp. — Ovalis, angustulus, subdepressus, pernitidus, testaceus, elytris proesertim ad basin obscurioribus, capite pectoreque fuscis ; anterius Icevigatus, elytris apicem versus dense, omnium subtilissime, vix perspicue punctu- latis; tarsis posterioribus elougatis, filiformibus. Long, li m.m., lat. f m.m. This species resembles extremely Notomicrus Itevigatus (No. 4) in size, form, and appearance, but it is readily distinguished from it by the fact that the apical half of the elytra is covered by a close excessively fine punctuation, instead of being polished and shining. The antennte are rather elongate and slender. I have seen but two individuals, they have the anterior tarsi quite slender, but I can form no opinion as to their sex. South America, (Rio Tapajog, above Itaituba, 13. 3. 1874, Dr. Trail). 1109. L 3.— Genus IIYDROCOPTUS. Anterior tibise destitute of a curved spur, with sharply defined, rectangular, outer apical angle ; posterior coxal cavities very distinctly sepai'ated, coxal notch broad. The five species* occur in the tropics of the Old World. 8. Hydrocoptus subfasciatus, n. sp. — Oblongo-ovalis, transversim sat convexus, subnitidus, testaceus, elytris fusco-testaceis, fascia subbasali interrupta maculaquf * In addition to these the following also belongs to the genus, viz : — Hydrocoptus rufulus, Motsch. (No. 1,334, huj. op.); very possibly identical with No. 9 ; Burmah. ana 262 On Aquatic Carnivorous Coleoptera or Dytiscidce. ante-apicali pallidioribus, seriebus 5 vel 6 punctorum impressorum minus regulari- bus ; corpore subtus impunctato ; antcnnis brevibus, simplicibus, articulis baud trans versis. Long. 23, lat. Is m.m. I can see no sexual difterences among the few individuals at my disposal ; the pale marks on the elytra are ill-defined, and sometimes scarcely to be distinguished. Australia, (Rockhampton). 464. 9. Hydroporus rubescens, Clk. M.C — Oblongo-ovalis, transversim sat convexus, nitidus,testaceus,elytris seriebus subregularibus punctorum impressorum minutorum; corpore subtus impunctato ; antennis brevibus, articulis 4 — 10 leviter transversis. Long. 2, lat. 1 m.m. I see no sexual diflferences amonop the small series I have examined: It is possibly the insect Motschulsky intended to name Hydrocoptus rufulus. Etudes Ent. IS 59 p. 44. Siam, (Bangkok, Castlenau) ; Java (fide Clark). 465. 10. Hydrocoptus vittatus, n. sp. — Oblongo-ovalis, transversim minus convexus, nitidus, testaceus; elytris fuscis, vitta iudeterminata marginalialiaque juxta-suturali abbreviata pallidis, seriebus obsoletissimis punctorum impressorum ; corpore subtus impunctato; antennis brevibus, articulis]4 — 10 leviter transversis. Long. 2, lat. 1 m.m. Though apparently very closely allied to Hydroporus rubescens (No. 9), this species is very easily distinguished by the colour of the elytra. Northern India, (Boyd) ; Sarawak, (Marquis Doria). 466. The individual from Sarawak differs slightly from the type from Northern India : it has the punctures of the elytra scarcely so fine, and the antennae not quite so short. 11. Hydrocoptus seriatus, n. sp. — Oblongo-ovalis, transversim sat convexus, pernitidus, testaceus, elytris castaneis, seriebus punctorum impressorum cons|)icuis ; corpore subtus impunctato ; antennis brevibus, articulis baud transversis. Long. 2\ m.m. The larger size and the much more consjiicuous series of punctures on the elytra readily distinguish this from the preceding species Hydrocoptus vittatus (No. 1 0) ; it is much smaller than Hydrocoptus bivittis and has the series of punctures more regular and distinct. Madagascar, (Wehncke). 608. 12. Hydrocoptus bivittis, Motsch. Hydroporus bivittis, M.C. — Oblongo-ovalis, On Aquatic Carnivorous Colcoptera or Dytiscidce. 263 transversim sat convexus, nitidus, rufo-testaceus, tliorace anterius et posterius vao-e infuscato ; elytris nigro-fuscis, vage rufo-signatis, seriebus punctorum abbreviatis ; corpore subtus nitido, processubus coxalibus sparsim punctatis ; anteunis brevibus, articulis baud transversis. Long. 3, lat. ij m.m. The yellow marks of the elytra consist of the outer margin, an abbreviate vitta near the suture, an indistinct small mark between it and the shoulder, and another indistinct subapical one. The series of punctures are numerous and distinct, moderately regular, but becoming obsolete before the base and apex. I have seen but a single individual. Northern India, (coll. Bouvouloir). 4G7. 11. 1. Group NOTERINI. The posterior femur destitute of group of cilite at the extremity of the hind margin ; anterior tibia with a curved apical spur ; prosternal process rounded behind (or obtusely acuminate, not truncate). This group comprises only three genera. Anterior tibia short, broad, and " siibtriangular, with well-marked below.) outer apical angle ; the curved spur short and inconspicuous. A single South American species. f PRONOTERUS, {vide Anterior tibia, with indefinite outer angle, and bearing a very - distinct curved spur. The spur moderately large, hind 1 tibife, but little flattened and ( YOTFPf^^ I 'rl ''fi'i ^ dilated. European aud Mediter- | ' ^ \- " ■) ranean species. J The spur very conspicuous ; hind ' tibise markedly flattened and dilated. Madagascar and African species. SYXCnORTUS, {vide p. *" 2G4.) I. i.— Genus PRONOTERUS. Anterior tibia with acute outer apical angle ; the curved spur small. The single species is South American. 13. Pronoterus punctipennis, n. sp. — Oblongo-ovalis, transversim convexus, nitidus, testaceus; elytris castaneis, serie abbreviata subregulari punctorum majorum, et versus apicem crebrius, sat fortiter, irregulariter punctatis ; corpore subtus impunctato, nitido ; antennis brevibus. Long. 2?, lat. If m.m. I have seen only three individuals; they are males and have the basal joint of the front tarsi much thicker than those following it. Brazil, (Santa Rita, August and September, 18.50, Dr. Sahlberg). H 264 On Aquatic Carnivorous Coleoiotrra or Dytiscidce. ]. 5.— Genus SYNCHORTUS. Anterior tibipe with indefinite outer apical angle, with elongate curved spur; antennas slender ; hind tibia) broad and flattened. The six species* occur in Madagascar and tropical Africa. 14. Synchortus simplex, n. sp. — Ovalis, sat convexus, castaneo-testaceus, nitidus, fere Isevis, elytris punctis 25aucis subtilissiniis. Long. 2l, lat. 1| m.m. The single male individual, which is all I have seen of the species, has the basal joints of the front and middle tarsi dilated, the latter furnished underneath with a very large cupule. Africa, (Gaboon). 516. 15. Synchortus aciculatus, n. sp. — Ovalis, sat convexus, castaneo-testaceus, nitidus, Isevis, sed elytris versus apicem et exterius punctis imbricatis sat approxi- matis. Long.' 2s, lat. ll m.m. The only individual I have seen is a female, and differs from Synchortus simplex only by the tarsi and the elytral sculpture, so that I believe the two are probably the sexes of one species. Africa, (Gaboon). 517. IG. Synchortus sparsus, n. sp. — Ovalis, sat convexus, castaneo-testaceus, nitidus, Isevis, sed elytris apicem versus et exterius punctis parvis sub-asperatis, baud numerosis. Long. 3s, lat. ll m.m. The single female I have seen of this species differs from Synchortus aciculatus, by its rather larger size, and the much smaller punctures on the elytra. Africa, (Gaboon). 518. 17. Synchortus duphcatus, n. sp. — Ovalis, sat convexus, castaneus, nitidus, laevis, elytris punctis paucis subtilissimis. Long. 3^, lat. 2 m.m. I have seen only males of this species, they are extremely similar to Synchortus simplex but are twice the size. Madagascar. 519. 18. Hydrocanthus asperatus, Fairm. Ann. Soc. Fr. 18G3 p. 199.— Ovalis, sat * The following also belongs to Synchortus :—Noterus imbricatus, King, (No. 1,498, hiij. op.), near No. 18; Eastern Africa. On Aquatic Carnivorous Coleoptera or Dijtiscidce. 265 convexus, castaneus, nitiJus, lajvis, sed elytris punctis magiiis, imbricatis, numerosis, basin versus evanescentibus; sutura Igevi. Long. 85, lat. 2 m.m. I have seen only females, they are perfectly similar to Synchortus duplicatus except in the tarsi, and in the sculpture of the elytra, and I have little doubt the two are the sexes of one species. Madagascar. 520. 19. Hydrocanthus rugoso-punctatus, Wehncke, Berh Zeit. 1876, p. 221. — Ovalis, sat convexus, castaneus, nitidus, elytris punctis magnis, imbricatis numerosis, basin versus hand subtilioribus ; sutura Isevi. Long. 3f m.m. lat. 2 m.m. I have seen a single specimen, it is a female, and distinguished from Hydrocanthus asperatus (No. 18), by the fact that the punctures on the basal portion of the elytra are as coarse as those on the apical portion. Madagascar, (Wehncke). G09. I. 6.— Genus NOTERUS. Anterior tibia with indefinite outer apical angle, and with rather long curved spur ; antennae more or less incrassate ; hind tibial rather slender, scarcely flattened. The six species are found in the Eurojiean region and Japan. 20. Dytiscus clavicornis, de Geer. Noterus clavicornis, M.C. — Ovalis, sat convexus, fere angustus, sat nitidus, testaceo-castaneus, elytris punctis magnis, anterius subseriatis, ante basin desinentibus. Long 4, lat. 2s m.m. Mas, antennis incrassatis, irregularibus, articulis quinto et sexto pra^sertim majori- bus, illo quam hoc (quo valde transverse) duplo longiore ; capite subtus prosternoque utrinque nigro-maculatis, hoc medio deplanato. Fcm., antennis fere regularibus, corpore subtus concolore ; prosterno medio trans- versim convexo. This species varies but little ; the elytra and ventral segments are sometimes of more obscure colour. Europe. From Scandinavia to Portugal. Not common. 521. 21. Dytiscus capricornis, Herbst. Noterus semipunctatus, M. C. — Ovalis, convexus sat nitidus, castaneus, antice dilutior ; elytris punctis magnis, profundis, basin versus desinentibus; prosterno medio carinato. Long. 4i, lat. 2h m.m. Mas, antennis incrassatis, irregularibus, articulis 5" et 6° longitudine subtequalibus haud transversis ; capite subtus prosternoque latius nigricantibus ; femoribus cum •2G(j On Aquatic Carnivorous Coleoptera or Dytiscidie. tibiis anterioribus femoribusque intermediis versus apicem nigris, pectore abdomiiie- que fuscis. Fern., antennis fere regularibus ; corpora subtus conclore. Europe : including Coraica, Sardinia, and Capiia ; an abundant species. 522. 22. Noterus convexiusculus, Reiche, M.C. — Mas, mari D3'tiscic apricornis omnino similis, sed elytris punctis vix magnis, parcioribus, anterius seriatis et desineutibus. Long. 4i, lat. 2j m.m. I think it probable this will prove to be a variety of Dytiscus capricornis (No. 21). I see nothing to distinguish it except the diminished punctuation of the elytra. Syria. 523. 23. Noterus ponticus, n. sp. — Ovalis, latiusculus, sat convexus, nitidus, testaceus, elytris castaneo-testaceis punctis tantum minutis munitis ; prosterno medio subtilius carinato. Long. 4i, lat. 21 m.m. Mas, antennis incrassatis, irregularibus, articulis 5° et 6° longitudine subsequalibus baud transversis ; genis prosternoque utrinque nigris ; pedibus anterioribus magis obscuris. Fcm., antennis fere regularibus ; oorpore subtus concolore. This species resembles Noterus lasvis (No. 25), but is very distinct from it by the male antennas which are formed as in Dytiscus capricornis (No. 21) and by the absence of the pubescent spot on the hind femora ; it is readily distinguished from Dytiscus capricornis, by the absence of the large punctures on the elytra, and by the more finely carinate prosternum ; the antennae of the male although similarly formed to those of Dytiscus capricornis are slightly broadei*. Mesopotamia. G 1 5. 24. Noterusjaponicus, Sharp, Tr. Ent. Soc.Lond., 1873, p. 52. — Ovalis, latiusculus, convexus, nitidus, castaneus, antice dilutior ; elytris apicem versus punctis minutis anterius seriatis. Long. 43, lat. 22 m.m. Mas, antennis paulo iucrassatis, articulis G — 10 magnitudinibus subtequalibus ; capite subtus utrinque, prosterno anterius abdomineque colore obscurioribus, femoribus tibiisque anterioribus nigris ; prosterno medio baud carinato. Fern., corpore subtus pediljusque ferrugineis concoloribus, prosterno medio sat carinato. Though very similar to Noterus lasvis (No, 25) the species is readily distinguished by the absence of the pubescent spot on the hind femora, and by the different characters of the male. Japan. 525. On Aquatic Carnivorous Coleoptera or Dytiscida. 267 25. Noterus Ifevis, Sturm, M.C.— Ovalis, latiusculus, sat convexus, nitidus, castaneus, antice dilutior ; elytris apicera versus punctis minutis ; prosterno medio carinato ; femoribus posterioribus subtus apice macula densa pubescentige. Long. 4^, lat. 2\ m.m. Mas, antennis breviusculis, irregularibus, articulo quinto maximo, quam sexto valde transverso latiore et duplo lougiore, articulis 7 — 10 longitudine latioribus ; corpore subtus femoribusque colore obscuriore ; tibiis posterioribus intus densissime ciliatis. Fem., antennis fere regularibus, corpore subtus ferrugineo, fere concolore. Southern Euvojie, and Algeria. 524. II. 2. — Group SuPHisiNi. Swimming legs very feeble, rather widely separated at their articulation ; the femora with elongate cilise at the extremity of their hind margin ; front coxse placed very near the front edge of the prosternum, this latter thickened along the middle longitudinally ; front tibia3 very twisted, with an extremely large terminal hook. The group comprises only two genera ; they are remarkably globose insects, although distinctly acuminate behind. Prosternum forming a prominent angle in front of anterior ) ^„r zjT-T-rc / -j i i % coxse. A single North American species. / ^ ^^^^ ^^^ (''*«« below.) Prosternum flexed in a gradual curve in front of anterior ( r-Trnrjrc/ -i coxEe. South American and West Indian species. ]'^'^^ ^'^^^ (''■^''^ P- 26»-) I. 7.— Genus COLPIUS. Middle of the prosternum so prominent in front that it forms a conspicuous outstanding rectangle ; epipleurre abruptly inflexed, horizontal through their whole length. The unique species is North American. 26. Colpius inflatus, Leconte, M.C. — Convexus, ovalis, postering sat acuminatus, sine pubescentia, opacus, niger, antennis pedibusque rufis, supra sanguineo- maculatus, subtus capite thoracisque lateribus rufescentibus ; elytris fortiter punctatis ; corpore subtus opaco, coxis punctis paucis magnis, abdomine impunctato, margine apicali setoso. Long. Si, lat. 2i m.m. United States, (Louisiana, Florida, fide Crotch). 463. TRANS. BOT. DUE. SOC, N.S. VOL. n. 2 N 268 0?i Aquatic Carnivorous Coleoptera or Dytiscidce. I. S.— Genus SUFIIIS. Middle of presternum not prominent in front ; epipleurse althougli abruptly inflexed, not comi^letely horizontal but only obliquely so (except at the humeral angle). The three species are found in South America and the Antilles. 27. Suphis cimicoides, Aube, M.C. — Valde convexus, ovalis, posterius acumi- natus, sine pubescentia, nitidus, ex ferrugineo-sanguineo nigroque vage variegatus, antennis jDedibusque rufis ; densius fortiterque punctatus ; antennis elongatis ; corpore subtus nitido, abdomine minus conspicue punctulato. Long. 4 m.m., lat. 21 m.m. South Amei-ica ; Cayenne, Antigua, (Brazil fide Aubc). The specimens from Antigiia ai-e smaller, and have the antennae a little shorter than the type from Cayenne. 4G1. 2S. Suphis subtilis, n. sp. — Valde convexus, ovalis, posterius acuminatus, sine pubescentia, nitidus, rufo-ferrugineus ; supra vage irregulariterque nigro- sio'natus dense sat subtiliter punctatus; antennis minus elongatis, corpore subtus nitido, abdomine minus conspicue punctulato. Long. 3's, lat. 2^ m.m. Very closely allied to S, cimicoides, but rather smaller, with the antennae shorter, and the punctuation of the thorax finer. South America ] Ne-\^' Granada, Cumana. 462. 29. Suphis difformis, n. sjj. — Valde convexus, ovalis, posterius acuminatus, sine pubescentia, nitidus, rufo-ferrugineus, supra irregulariter vageque fusco-signatus ; elytris crebrius et evidenter, quam thorace densius punctatis ; antennis elongatis ; corpore subtus nitido, abdomine inconspicue punctulato. Long. 4, lat. 2f m.m. This species is extremely similar to Suphis cimicoides, but has the antennte a little longer, and the punctuation of the thorax is more sparing and not so coarse, especially towards the front and sides. South America; Bahia ; Santa Rita, September 1850, Sahlberg; (Oiinoco, King, in Dejean's collection). 460. 11. 3. — Group Htdeocanthini. Prosternal process broad, and with broad, subtruncate hind-margin ; posterior femora with a conspicuous group of cilia; at their outer angle. On Aquatic Carnivorous Coleoptera or Dytiscidce. 269 This group comprises only two genera ; both have a very wide geographical distribution. Prosternal process very broad behind ; bind tibife very broad ; ) EYDROCANTHUS, size 4-7 m.m. of length. | {mde p. 279.) Prosternal process moderately broad behind; hind tiljire raihev \CANTHYDRUS, slender ; size less than 4 m.m. of length. j (vide below). I. 9.— Genus CANTHYDRUS. Prosternal pi'ocess only moderately broad, not broader than long ; swimming legs rather slender. The numerous species* inhabit the warmer parts of the Old and New Worlds ; they are but little understood as yet, and very similar to one another. 30. Canthydrus sculpturatus, n. sp. — Ovalis, sat convexus, nitidus, ferruginous, elytris abdomineque fuscis ; illis crebre profunde arguteque punctatis, punctis elongatis, versus apicem densioribus. Long, 2|, lat. If m.m. The punctuation of the elytra makes this a very easily distinguished species. The only individual I have -seen is a female, and has the apical ventral segment almost without impression. Brazil, (Santa Rita, August, 1850, Dr. Sahlberg). 515. 31. Canthydrus vicinus, n. sp. — Ovalis, sat convexus, nitidus, ferrugineus, elytris sat crebre punctatis; prosterni jirocessu parce punctate. Long. 2f, lat. If m.m. Extremely similar to Canthydrus sculpturatus but not so broad, and with prosternal jsrocess and coxal laminaa more sparingly punctured. The two individuals before me are male and female. The male has a small indistinct oblonar flattening or depression at the base of the apical ventral segment in the middle ; in the female there is a very obscure indication of carination along the middle of the hinder part of this segment. The male specimen has the elytra more closely and coarsely punctured than in the female, but I do not know whether this is sexual or merely an individual variation. Brazil, (Santa Rita, August, 1850, Sahlberg). 514. * In addition to those enumerated in the text, the following species should probably be placed in Canthydrus. Hydrocanthus auritus Regt. (No. 1,324 huj. op.) ; Manilla. — Hydrocanthus lineatus, Wehncke (No. 1,326), near No. 49; Mexico. — Hydrocanthus rubripes. Boh. (No. 1,328), 1 near No. 45; Uruguay. — Hydrocanthus testaceus, Boh. (No. 1,330), near No. 70; China. — Suphis puncticoUis, Crotch, (No. 1,506), near No. 48; North America. — Supliis semiiaunctatus, Lee. (No. 1,507); North America. — Whether Hydrocanthus nanulus, Lee. (No. 1,327, North America) belong to the genus, is somewhat doubtful. ■ - 2 N 2 270 On Aquaiic Carnivorous Coleoj^tera or Dytiscidcp. 32. Canthydrus ovatus, n. sp. — Breviter ovalis, sat convexus, nitidus, ferrugineus, elytris obscurioribus, crebre fortiter punctatis. Long. 2 1, lat. 1| m.m. This species is intermediate between Suphis gibbulus (No. 38) and Canthydrus insularis (No. 35), it is smaller and shorter than the former, and has the coxal laminas more sparingly punctured ; while it is less short and rotund than Canthydrus insularis, and has the antennge shorter. I have seen only one female ; it has the apical ventral segment impressed on each side so as to appear distinctly carinate along the middle. BrazD, (Santa Eita, September, 1850, Dr. SaUberg). 513. 33. Canthydrus grossus, n. sp. — Ovalis, posterius acuminatus, convexus, nitidus, testaceus, elytris sordidis, cum thorace sat crebre fortiter punctatis. Long. 4 m.m., lat, 2| m.m. In this species the thorax is even more closely and distinctly jjunctured than are the elytra. The large size I'eadily distinguishes the species from its allies. The only specimen I have seen appears to be a female, and has the apical ventral seg- ment simple. Brazil, (Pemambuco, Brussels Museum). 512. 34. Canthydrus I'otundatus, n. sp. — Subrotuudus, convexus, testaceus, nitidus, elytris sordidis, obsolete punctatis ; prosterni processu profunde canaliculato ; coxarum laminis parce punctatis. Long. 1| m.m., lat. ll m.m. I have seen but a single individual of this minute species, its very short rotund form, and the diminished punctuation readily distinguish it. Brazil, (Pemambuco, Brussels Museum). 511. 35. Canthydrus insularis, n. .sp. — Brevis, rotundato-ovalis, convexus, nitidus, rufo-testaceus ; elytris obscurioribus, crebre, fortiter sed baud argute punctatis. Long. 2, lat. li m.m. The male has the apical ventral segment nearly simple. Though I have seen but a single individual I have no doubt it is distinct from though very closely allied to the preceding, being larger, of more rotund and convex form. San Domingo, (Coll. Bouvouloir). 510. 36. Canthydrus punctipennis, n. sp. — Ovalis, brevis, latiusculiis, sat convexus, nitidus, ferrugineus, elytris crebre fortiter jDunctatis. Long. 2|, lat. If m.m. The sexual characters appear to be the same as in Noterus bicolor (No. 37) ; On Aquatic Carnivorous Colcoptera or Dytiscidce. 271 but I think the specimens indicate a distinct species, as besides being pale in colour, they are larger and a good deal broader, and have the hind le^^-s more elongate. North America, (CarolLaa). 509. 37. Noterus bicolor, Say. Su2)his bicolor, M.C. — Ovalis, brevis, latiusculus sat convexus, nitidus, ferruginous ; elytris nigricantibus, crebre fortiter punctatis, corpore subtus nigro-rufo. Long. 2i, lat. Ik m.m. This species scarcely differs from Suphis gibbulus (No. 38) except by the sexual characters, and that it generally has the elytra and under surface dai-ker in colour. In the male the apical ventral segment is without evident impressions, but in the female it is rather deeply impressed on each side so as to appear somewhat cariuate along the middle. United States, (Carolina). 508. 38. Suphis gibbulus, Aube, Spec. p. 414. — Ovalis, brevis, latiusculus sat con- vexus, nitidus, ferruginous, elytris crebre fortiter punctatis. Long. 2|, lat. vix 1| m.m. In each sex the apical ventral segment is depressed on its middle portion, so that the sexes are difficult to distinguish, the depression however is a little greater in the male than it is in the female. North America. 507. 39. Hydrocanthus tenuicornis, Chev. M.C. — Ovalis, sat convexus, nitidus, ferruginous, crebi-e fortiterque punctatus. Long. 2j m.m., lat. 1| m.m. This species is very close to Suphis gibbulus (No. 38), but is more elongate and the punctation of the elytra is deejDor. I have seen but one individual, which is a female, and has the aj^ical ventral segment rather deeply impressed on the middle. Cuba, (Brussels Museum). 50G. 40. Canthydrus subsignatus, n. sp. — Ovalis, sat convexus, baud curtus, nitidus, castaneus ; elytris fusco-castaneis, vage testaceo-signatis, crebre fortiter punctatis ; prosterni processu canaliculato ; coxarum laminis parcius punctatis. Long. 21, lat. ll m.m. The marks on the elytra are ill-defined ; the lateral margin is yellow, as are also two spots on the middle of each, and some indistinct marks near the suture. '2 1 2 Oil Aquatic Carnivorous Coleoptcra or DijtiscidcB. The only individual I have seen is a female, and it has an oblong depression on the apical ventral segment, -which at the extremity is divided by a short plica. Panama 527. 41. Canthydrus dilutus, n. sp. — Ovalis, sat convesus, posterius acuminatus, testaceus, nitidus, elytris crebre obsolete punctatis. Long. 2f, lat. 1\ m.m. Though the species is pretty closely allied to Hydrocanthus tenuicornis (No. 39), it is of narrower, more elongate, and convex form, and the elytra are much more obsoletely punctured : there does not appear to me to be any difference in the sexes, except in the tarsi. Brazil ; Bahia. 505. 42. Noterus buqueti. Lap. Hydrocanthus huqueti, M.C. — Ovalis, latus, minus convexus, breviusculus, pernitidus, sanguineo-rufus, elytris iridescenti-fuscis, maculis subdistinctis quatuor apiceque rufis ; prothoracis margine laterali lato. J,ong. 3, lat. ]f m.m. I have seen but a single individual from Dejean's collection, the sjDecies is readily distinguished from the allies by the broad thoracic margin, which is formed as in the genus Hydrocanthus. The spots on the elytra are not very distinct ; besides the four which form a transverse row across the middle, there are other two near the apex which are scarcely to be distinguished owing to the more dilute colour of the hind part of the elytra. The individual (in M. de Bou- vouloir's collection) is 1 think a female, but shows no apparent peculiarity. ijouth America, (Cayeime). 504. 43. Canthydrus remator, n. sp. — Ovalis, sat convexus, et sat elongatus, uitidus, ferrugineus ; elytris vix obscurioribus, fere impunctatis, seriebus punctorum duabus sat distinctis ; prosterni processu dense punctato, canaliculato. Long. 3, lat. If m.m. South America, (Uniguay). 526. 44. Canthydrus curtus, n. sp. — Ovalis, latiusculus, minus elongatus, sat convexus, uitidus, rufus ; elytris iridescenti-fuscis, serie punctorum sat distincta ; prosterni processu canaliculato. Lung. 3, lat. 1| m.m. This species is shorter, and so comparatively broader than its allies, and the under surface is pale and unicolorous. In each sex the apical abdominal segment On Aquatic Carnivorous Coleoptcra or Dytisache. 273 is somewhat flattened or depressed, except at the extreme base ; so that the sexes can only be distinguished by the structure of the tarsi. South America ; Amazons. (Pampas Germain). .503. The individual from the Pampas in M. de Boiivouloir's collection is slightly larger and more convex, and elongate, but if a distinct species it must be a very closely allied one. 45. Canthydrus brevicornis, n. .sp. — Ovalis, convexus, nitidus, supra nigricans, capite thoracisque lateribus picescentibus, antennis fuscis, basi testaceo ; corpore subtus anterius rufescente, posterius nigricante ; elytris obsoletissime punctatis, seriebusque punctorum subdistinctis ; prosterni processu canaliculate. Long. 2f , lat. li m.m. Closely allied to Hydrocanthus nigrinus (No. 47), but not half the size, and Avith the penultimate joints of the antennas much shorter. The only individual I have seen is I think a female, but has only an indistinct impression on each side of the apical ventral segment, BrazO, (Parana). 502. 46. Canthydrus rufipes, n. sp. — Ovalis,sat convexus et elongatus, pernitidus,piceo- rufus, elytris nigricantibus, antennis testaceis; corpore subtus anterius rufo, posterius nigricante ; elytris seriebus duabus sub-distinctis punctorum. Long. 3^ lat. 2 m.m. Extremely similar to Hydrocanthus nigrinus (No. 47), but rather less convex, a little paler in colour, and the prosternal process without channel. The female has the apical ventral segment impressed on each side. Cuba ; Amazons ; (Parana ?). 501. 47. Hydrocanthus nigrinus, Aube, M.C.— Ovalis, convexus, sat elongatus, pernilidus, supra niger, capite thoraceque versus late ra picescentibus, antennis fuscis, basi testaceo ; corpore subtus anterius rufescente posterius nigricante ; elytris serie punctorum distincta, preterea fere impunctatis; prosterni processu canaliculate. Long. 3i, lat. 2 m. The female has a large impression on each side of the apical ventral segment, of which there is no trace in the male. South America ; Bahia, (Antilles and Brazil fide Aube). 500. 48. Suphis lineatus, Horn, Tr. Am. Ent. Soc. 1871, p. 329.— Ovalis, sat convexu.s, nitidus, rafescens, prothorace medio fusco ; elytris sutura vittisque tribus lalis (externa interrupta) nigris; elytris crebre sat fortiter punctatis. Long. 3, lat. ll m.m. 274 On Aquatic Carnivorous Colcoplera or Dytiscida. The disposition of the marks on the elytra is quite similar to that existing in Canthydrus grammicus (No. 50), but the black marks are broader ; the difference in the punctuation of the elytra renders the two very distinct. I have seen only a single individual, which is probably a male, it has the apical ventral segment, flattened or depressed except at the base. South California, (Cape St. Lucas). 499. 49. Canthydrus centralis, n. sp. — Ovalis, sat convexus, pernitidus, testaceus prothorace disco infuscato ; elytris uigris, vittis tribus testaceis, subseriatim punctatis. Long. 3, lat. ll m.m. In this species the black colour on the wing-cases predominates the yellow, so that this latter forms three rather narrow longitudinal stripes ; these commence at the base, and are there broadest, the internal one becoming gradually more indistinct behind, does not reach the extremity, the second is shorter and extends but little beyond the middle, the third extends to the apex, and in front sends off a branch to the shoulder, which is thus largely yellow ; besides these stripes the lateral margin in the middle is yellow. Although the surface is very polished, the subseriate punctuation of the elyti'a is very distinct, and on careful examination traces may be discovered of an irregular very obsolete punctuation. The sexes show little difference except in the tarsi, each having the greater part of the last ventral segment a little hollowed. Guatemala, (S. Geronimo, 1879, Champion). 11G8. 50. Canthydrus grammicus, n. sp. — Ovalis, latiusculus, sat convexus et elongatus, pernitidus, rufo-testaceus ; elytris sutura vittisque tribus (externa interrupta) nigris ; elytris j^unctis paucis subseriatis. Long. 3|, lat. 2 m.m. The sutural vitta extends to the apex, the one next to it nearly to the apex, while the middle one is considerably abbreviate, the outer one does not reach the shoulder, but there is a short humeral stripe which overlajis it. I have seen only four individuals, which are all females, and have the last ventral segment impressed on each side so as to make the middle part ajjpear prominent. South America; Amazons. 498. 51. Canthydrus concolor, n. sp. — Oblongo-ovalis, posterius acuminatus, convexus, nitidus, fulvus, elytris sparsim inconspicue punctatis. Long. 2|, lat. 15 m.m. This species resembles the larger individuals of Hydrocanthus flavus (No. 70) exactly, but appears to me to have the posterior tarsi, shorter and thicker. Madagascar. 491. On Aquatic Carnivorous Coleoptera or Dytiscidce. 275 52. Hydrocanthus semperi, Wehncke, Berl. Zeit. 1876, p. 223.— Ovalis, sat couvexus, posterius atteuuatus, pernitidus, niger, capite protlioraceque ad angulos anteriores rufo-testaceis, illo posterius infuscato ; antennis testaceis, pedibus obscure rufis. Long. 2| m.iii., lat. Ih m.m. This is a small and rather short species, distinguished from H. luctuosus (No. 60) and allies by the unspotted elytra. Philijipiiie islands ; Luzon. G14. 53. Canthydrus arabicus, n. sp. — Breviter ovalis, convexus, posterius attenuatus, pernitidus, piceus, capite protlioraceque lataribus testaceis ; elytris guttula parva pone medium testacea, omnino Itevigatis ; antennis testaceis, pedibus rufis. Long. 3*, lat. If m.m. This species is very closely allied to Hydrocanthus guttula (Xo. 54), but is rather smaller, and besides the colour differences, is remarkable for being without any punctures on the wing-cases. Immature individuals are entirely yellow. Arabia, (Hedjaz, Millingen). lliT. 54. Hydrocanthus guttula, Aube, M.C. — Ovalis, convexus, posterius attenuatus, pernitidus, niger, capite anterius, thoraceque ad angulos anteriores rufo-testaceis ; elytris guttula parva pone medium testacea, punctis sparsis sat conspicuis ; antennis testaceis; pedibus rufis, posterioribus magis obscuris. Long. 3, lat. 15 m.m. This species is broader and more convex than Hydrocanthus notula (No. 55), and has the yellow colour at the anterior angle of the thorax much less extended ; the punctures on the elytra are more conspicuous. Madagascar ; Mauritius. 490. 55. Hydrocanthus notula, Er. M.C. — Ovalis, sat convexus, posterius attenuatus, pernitidus, niger, capite anterius, prothoracisque lateribus rufo-testaceis, elytris guttula parva pone medium testacea ; antennis testaceis, pedibus rufis, posterioribus magis obscuris. Long. 3g^, lat. l| m.m. The red colour on the head and thorax, is more extended in the male than in the female ; there is sometimes a minute yellow dash at the base of the elytra close to the outer marofin. o Egypt ; Tangier ; (Angola fide Erichson). 489. 56. Canthydrus ornatus, n. sp. — Ovalis, sat convexus, posterius attenuatus, pernitidus, niger, capite, prothoracis lateribus, elytrorum macula humeral! aliaque TRANS. ROT. DUB. SOC, U.S. VOL, II. 3 0 276 On Aquatic Carnivorous Coleoptera or Dytisciche. pone medium rufo-testaceis ; pedibus rufis, posteriorlbus magis obscuris ; antennis testaceis. Long. 3h, lat. 2 m.m. The yellow colour at the sides of the thorax is here very broad ; the spot at the shoulder of the elytra is also large, and between it and the suture there are obscure traces of another basal spot, the spot behind the middle is rather small. Persia. 488. 57. Hydrocanthus morsbachi, Wehncke, Berl. Zeit. 1S76, p. 222. — Ovalis, sat convexus, posterius attenuatus, pernitidus, nigei-, capite anterius anguste, prothorace ad angulos anteriores, elytris niaculis duabus ad basin, aliaque transversa pone medium rufo-testaceis ; antennis testaceis, pedibus rufis, posteriorlbus obscurioribus. Long. 3 m.m., lat. l§m.m. The yellow colour on the head and at the anterior angle of the thorax is very small in extent, on the other hand the two basal spots on the elytra are rather laro-e, and the post-medial spot is broad, so as to form a transverse mark. I have seen but one individual. Cochin China, ("Wehncke). G13 58. Canthydrus frontalis, n. sp. — Ovalis, sat convexus, posterius attenuatus, pernitidus, niger, capite anterius, prothorace ad angulos anteriores, elytris maculis duabus magnis ad basin fasciaque pone medium rufo-testaceis ; antennis testaceis, pedibus rufis, posteriorlbus obscurioribus. Long. 2|, lat. 11 m.m. In this species the limit between the colours on the head is angular : the marks on the elytra are a longitudinal oblong one at the shoulder, a rather large spot between that and the suture, and a transverse spot or short band beyond the middle. Arabia ; Bombay. 487. 59. Canthydrus sexpunctatus, n. sp. — Ovalis, sat convexus, posterius attenuatus, pernitidus, niger, capite anterius rufo, prothorace ad angulos anteriores, elytrisque maculis sex testaceis, pedibus rufis, posteriorlbus obscurioribus : antennis testaceis. Long. 21, lat. It m.m. The smaller extent of the yellow colour on the thorax seems to be almost all that distinguishes this species from Hydrocanthus luctuosus (No, 60). India ; Tranquebar. 486. 60. Hydrocanthus luctuosu.s, Aube, M.C. — Ovalis, sat convexus, posterius attenua- tus, pernitidus, niger, capite et prothoracis lateribus rufo-testaceis, illo vertice magis On Aquatic Carnivorous Coleoptera or Dytiscidce. 277 obscuro, elytris guttis duabus basalibus, aliaque post-medium testaceis ; pedibus rufis, posterioribus obscuris, antennis testaceis. Long. 3i, lat. If m.m. East Indiaj (Bombay fide Aube) . G 1 2. 61. Canthydrus angularis, n. sp. — Ovalis, convexus, posterius attenuatus, perni- tidus, niger, capite anterius, prothorace ad angulos anteriores, maculis duabus ad elytrorum basin alteraque pone medium rufis ; antennis testaceis, pedibus quatuor anterioribus rufis, posterioribus piceis. Long. 31, lat. If m.m. Siiiga23ore. 485. 62. Hydroporus Isetabilis, Walk. M. C. — Ovalis, minus latus, posterius attenuatus, sat convexus, pernitidus niger, capite, thorace pedibusque rufo testaceis, antennis testaceis ; thorace anterius et in basi obscure nigro ; elytris maculis duabus pone basin aliaque transversim elongata pone medium testaceis. Long, vix 2, lat. 1^. m.m. East India, (Ceylon fide Walker). 484. 63. Hydrocanthus weisei, Welincke, Berl. Zeit. 1876, p. 222. — Ovalis, posterius attenuatus, sat convexus, pernitidus, testaceus, prothorace versus basin infuscato, elytris nigricantibus, fascia interrupta pone medium, vitta longitudinali ab humero ad fasciam postmedialem descendente, maculaque magna basali testaceis ; pectore fusco, abdomine nigro. Long. 2h m.m., lat. vix Ih m.m. Closely allied to Hydrocanthus politus (No. 69) and much resembles the dark varieties of that species, but it is smaller and narrower, and has the apex of the elytra dark. Cocliin China, (Welincke). Oil. 64. Hydrocanthus quadrivittatus, Boh. M. C. — Ovalis, convexus, breviusculus, posterius acuminatus, nitidus, Isevis, rufo-testaceus, elytris obscurioribus, vitta laterali obliqua aliaque abbreviata prope suturam testaceis ; abdominis lateribus leviter infusoatis. Long. 3, lat. if m.m. The stripes on the elytra readily distinguish this species ; they are not sharply defined ; the exterior one starts from the humeral angle, and then leaves the outer margin and extends along the middle of the wing-case reaching the apex ; the inner mark is shorter and runs parallel with the suture, but does not extend much beyond the middle. Cape Good Hope, (Cafii-aria fide Boheman). 610. 278 On Aquatic Carnivorous Colcoptera or Dijtiscidce. 65. Canthydrus proximus, n. sp. — Ovalis, sat latus, posterius atteniiatus, convexus, pernitidus, niger, capite thoraceque minus la^te rufis, hoc macula magna anteriori basique transversim nigris, elytris maoulis duabus pone basin, aliaque pone medium transversis rufis ; antennis testaceis, pedibus quatuor anterioribus rufis, posterioribus piceis. Long. 3, lat. ll m.m. This species is very closely allied to Canthydrus nitidulus, but is not so broad and is more obscurely coloured. Siam, (Bangkok). 483. G(). Canthydrus nitidulus, n. sp. — Ovalis, robustus, posterius attenuatus, convexus, pernitidus, capite thoraceque rufo-testaceis, hoc basi maculaque in medio anteriori nigris ; elytris fere impunctatis, nigris, maoulis duabus pone basin, aliaque transversa recta pone medium testaceis ; subtus abdomine, pectoris prosternique medio nigricantibus, lateribus rufis ; antennis testaceis, pedibus rufis, tarsis tibiisque posterioribus piceis. Long. 3l, lat. if m.m. Northern China, (Kiu Kiang, G. Lewis) ; Formosa. 482. G7. Canthydrus flammulatus, n. sp. — Ovalis, posterius attenuatus, convexus, perni- tidus, rufo-testaceus, prothorace basi medio elytrisque nigricantibus, his fere im- punctatis, apice plus minusve dilutioribus, ad basin macula laterali longitudinali aliaque versus suturam in-egulari, et fascia transversa mediali angulata ad suturam latius interrupta testaceis ; abdomine plus minusve nigricante : tarsis posterioribus piceis. Long. 2|, lat. li m.m. Closely allied to Hydrocanthus haagi (No. 6S), but larger and more elongate, and with slight difterences in the colour and markings. Siaui, (Bangkok) ; Celebes, (Macassar, Beccari). 481. GS. Hydrocanthus haagi, Wehncke, Berl. Zeit. 1876, p. 222. — Ovalis, brevis, posterius attenuatus, convexus, pernitidus, rufo-testaceus, prothorace basi medio elytrisque nigris, his impunctatis apice late rufescentibus, macula laterali longitudinali, aliaque transversa versus suturam ad basin, et fascia transversa mediali valde undulata ad suturam augustius interrupta testaceis. Long. 2, lat. Ij m.m. This sjDecies is pale beneath ; its small size, and the much waved transverse fascia on the middle of the elytra distinguish it amongst its allies. Siam, (Bangkok). 480. 69. Hydrocanthus politus. Sharp, Tr. Ent. Sec. Loud. 1 873, p. 51. — Ovahs, posterius On Aquatic Carnivorous Colcoptcra or Dtjtiscidce. 279 attenuatus, convexus, pernitidus, Isete rufo-testaceus, Isevis, elytris nigris, maculis duabus magnis ad basin, fascia mediali interrupta apiceque testaceis ; abdomine utrinque infuscato ; prosterni pectorisque medio et laminis coxaruin dense punctatis. Long. 2f, lat. If m.m. In the markings of the elytra, the size of the spots varies, so that the yellow colour sometimes predominates over the black. Japan ; China. 479. 70. Hydrocanthus flavus, Motsch. M.C. — Oblongo-ovalis, posterius acuminatus, sat convexus, pernitidus, fulvo-testaceus, elytris fere impunctatis, prosterni pectorisque medio et laminis coxarum crebrlus punctatis. Long 2|, lat. if m.m. The small size and pale unvariegate unicolorous surface are the chief characters of this species. China : Siam, (Bangkok) ; Formosa : (East India fide Motschoulsky). 478. The specimens from Formosa are larger, and have the sides of the ventral segments infuscate, but 1 do not think it advisable to consider them a distinct species Avithout further evidence. I. 10.— Genus HYDROCANTHUS. Prosternal process extremely broad, broader than long ; swimming legs very stout. Species are found in most of the warmer parts of the world, but not in Europe.* 71. Hydrocanthus australasife, Wehncke, Berl. Zeit. 1876, p. 223.— Oblongo- ovalis, posterius acuminatus, transversim sat convexus, minus latus, pernitidus, uiger, antennis rufis, pedibus corporeque subtus piceis, elytris seriebus punctorum obsoletis, pone humeris leviter sinuatis ; spatio inter coxas anteriores sat lato ; prosterni pectorisque medio et laminis coxarum crebrius punctatis. Long. 5i, lat. 2«- m.m. The only difference between the sexes is the two or three cups on the under side of the front tarsi in the male. Northern Australia, (Rockhampton). 47G. 72. Hydrocanthus indicus, Wehncke, Berl. Zeit. 1876, p. 223.— Oblongo-ovalis, posterius acuminatus, transversim sat convexus, minus latus, pernitidus, castaneus, elytris vix perspicue punctatis ; spatio inter coxas anteriores sat lato ; prosterni pectorisque medio et laminis coxarum crebre punctatis. Long 5, lat. 2t m.m. * In addition to those enumerated in the text, the two following species may be referred, although with doubt, to the genus. Hydrocanthus fasciatus, Steinl. (No. 1,325 huj. op.). Hydrocanthus socius, Sahl. (No. 1,329) ; both fi-om South America. 280 On Aquatic Carnicorous Coleoptcra or hytiscidce. Closely allied to Hydi-ocanthus australasite, but not so elongate, and of a different colour. Siam, (Bangkok); (Cochin China fide Wehncke). 477. 73. Hydrocanthus oblongus, n. sp. — Oblongo-uvalis, sat convexus, pernitidus, castaneo-ferrugineus, elytris subiridescentibus, fere impunctatls. Long. 4, lat. 2 m.m. In the male the prosternal process is deeply hollowed out, and is nearly im- punctate ; and the apical ventral segment has an oblong dull patch in the middle at the apex ; in the female the prosternal process is flat and is punctured in a variable manner ; and the apical ventral segment is quite smooth and shining. North America. 492. 74. Hydrocanthus iricolor, Say. M.C. — Ovalis, sat latus, pernitidus, castaneo- ferrugineus, elytris subiridescentibus, seriebus tribus fere irregularibus et subdis- tinctis punctorum ; antennis minus brevibus. Long. 41, lat. 2^ m.m. Larger than Hydrocanthus oblongus, especially broader, and with the antennae more developed, and the elytral series of punctures not altogether effaced. North America, (Massachusetts). 493. 7.5. Hydrocanthus texanus, n. sp. — Ovalis, convexus, pernitidus, ferruginous, elytris nigro-iridescentibus ; corpore subtus posterius plus minusve nigricante. Long. 4i, lat. 2i m.m. This species is comparatively more convex than Hydrocanthus oblongus, and H. iricolor, and has the elytra blackish ; in respect of the antennae and elytral punctuation, and of the size it is intermediate between the two. Nortli America, (Texas). 404. V6. Noterus laevigatus, Brulle. Hydrocanthus IcBvigatus, M.C. — Ovalis, pernitidus castaneo-ferrugineus, elytris paulo obscurioribus indistincte pallido-reticulatis, seriebus punctorum subtilissimis. Long. 5, lat. 2h m.m. This species is extremely similar to Hydrocanthus iricolor, but the elytra instead of being concolorous are variegated by irregular pale marks forming a sort of coarse reticulation, this character is not however very conspicuous till the elytra are opened so as to show the light through them. South America ; Bahia, Orinoco. 495. 77. Hydrocanthus atripennis. Say. M.C — Ovalis, sat latus, valde convexus, On Aquatic Carnivorous Coleoptera. or Dijtiscidcp. 281 pernitidus, capite thoraceque rufis ; elytris iridescenti-nigricantibus, seriebus punctorum distinctis, lateribus pone humeros profundius excavatis ; corpore subtus rufo-obscuro, capite thorace(jue dilutiovibus, prosterni processu latissimo. Long. 41, lat. 24 m.m. Very similar toHydrocantlius texanus, but larger and much more convex, and with the thorax more dilated so that the elytra are more excavate at the sides, and the prosternal process is broader. In tire male the prosternal process is closely and finely punctured and a little hollowed in the middle ; while in the female it is flat, shining and impunctate. I have not seen any specimen of this species from Mexico, and there is thus some doubt whether it is really the H. atripennis, Say, which was described from Mexican individuals. Brazil, (Santa Eita, September, 1850; Boa Sorta, November, 1 850, Sablbcrg) ; (Mexico fide Saj-). 496. 78. Hydrocanthus debilis, n. sp.— Ovalis, sat convexus, pernitidus, castaneo- testaceus, elytris indistincte undulatim fusco-variegatis, fere omnino impunctatis. Long. 3i, lat. 2S m.m. The small size readily distinguishes the species from its allies as yet known to me : the elytra appear at first to be concolorous, but when opened are seen to be variegate by very undulated fuscous marks. The male has the prosternal process densely and finely punctured, and a little impressed, while in the female it is flat, and is coarsely and not densely punctured. South America ; Baliia ; Amazon's Valley. 497. 79. Hydrocanthus funebris, Fairm. Ann. Soc. Fr. 18G9, p. 187. — Ovalis, pos- terius acumiuatus, sat latus, pernitidus, niger, pedibus piceis, antennis rufis ; elytris seriebus tribus obscuris punctorum, lateribus sat sinuatis, spatio inter coxas anteriores sat lato ; prosterni pectorisque medio et laminis coxarum sat crebre punctatis. Long. (!i, lat. 31- m.m. There is but little difference between the sexes of this species ; the male has two or three cups on the under side of the second and third joints of the front tarsi. Madagascar. 475. 80. Hydrocanthus advena, n. sp. — Minus latus, convexus, pornitidu.-?, piceus, antennis rufis ; elytris pone humeris vix sinuatis, subUievigatis ; spatio inter coxas anteriores lato, baud elevato ; prosterno impuuctato ; coxarum posticarum parte elevata crebre punctata. Long. f)l m.m., lat. 2^ m.m. Basseterre {^ Guadeloupe). The only individual I have seen is in the collection of the Musee Eoyal at Brussels, and is labelled " Basseterre " I am not at all sure what locality is thus intended. 474. 282 On Aquatic Carnivorous Cnleoptera or Di/tisculce. 81. Noterus grandis, Lap. Hydrocanthus grandis,M.C. — Minus latus, convexus, pernitidus, piceus, capite thoraceque quam elytris dilutioribus, antennis rufis ; elytris pone humeros sinuatis, sublEevigatis ; spatio inter coxas anteriores minus lato, subelevato ; prosterno medio, pectoris coxarumque parte elevata crebre punctatis. Long. 7, lat. Zh m.m. In the male the apical ventral segment is very little if at all compressed towards the apex. Africa, (Senegal, Gaboon). 473. 82. Hydrocanthus deyrollei, n. sp. — Crassus, robustus, latiusculus, sat nitidus, niger, antennis rufis,pedibus piceis, elytris seriebus duabus punctorum sat distinctis,et versus latera punctis sparsis, lateribus pone humeros, vix sinuatis ; coxis anterioribus late separatis ; prosterno, pectore medio laminisque coxarum impunctatis. Long. 8 m.m. (vix), lat. il m.m. The male has the hinder part of the apical ventral segment much compressed so as to form a ridge terminating in a point. Africa, (Gaboon, Brussels Museum ; found I believe by H. Deyrolle). 472. II. 4. — Group Vatellixi. Prosternal process not reaching the metasternum, but terminating in front of and between the middle coxeb; front andmiddle tarsi four jointed, frequently very elongate ; outline of body discontinuous at junction of thorax and elytra. S^Yimraing legs slender. This group represents in the Dytisci Fragmentati series the Hydroporides of the second series. The three genera are South American, and very rare in collections, except Derovatellus. Ventral sutures very deep, YATELLUS,{mde\>.2ib) Ventral sutures normal, Mesostemum very largely visible ; \ MAOROVATELLUS, size moderate (G-8 m.m. long), j (vide below). Mesostemum but little yhMe;} DEROVATELLUS, .size small (4 m.m. long). J (yide p. 286). L II.— Genvis MACROVATELLUS. Mesostemum largely exposed between the prothorax and metasternum. Outline of thorax and elytra very discontinuous. The Macro vatelli are moderately large insects (6 — 8 m.m. long). The species* are very similar to one another and extremely rare in collections. ♦Vatellus grandis, Buq. (No. 1,511, luij. op.), from Cayenne is probably another species of the genus. On Aquatic Carnivorous Colcopiern or DytiscidcB. ■■2S:i 83. Macrovatellus lateralis, n. sp. — Oblongo-ovalis, fere sine pubescentia, opacus, densius punctatus, fuscus, pedibus antenuisque l:jete rufo-testaceis, capite, thoracis lateribus, elytrorumque signaturis marginalibus ferrugineis ; thorace elvtris angustiore, lateribus baud sinuatis,angulis posterioribus fere rectis, fortiter et crebrius sed baud profunde puuctato ; elytris punctatis, scabriusculis; coxis posterioribus for- titer, sed subobsolete punctatis, abdomine obsolete punctate. Long. Gh, lat. 3h in. in. The male has the front and middle tarsi broader than the female, the second joint of the front ones being scarcely so long as its greatest width ; the middle trochanters and the basal portion of the femora are set with a ridge of dense yellow pubescence. In the female when the sole of the front tarsus is looked at, it is seen that the length of the third joint is quite twice as great as its breadth. South America, (Uruguay). 438. 84. Macrovatellus rudis, n. sp. — Oblongo-ovalis, fere sine pubescentia, opacus, densius punctatus, piceus, pedibus antennisque obscure rufis, capite ferrugineo, prothorace elytrisque lateribus vage et obsolete ferrugineo-signatis ; thorace elytris multo angustiore, lateribus haud sinuatis, angulis posterioribus fere rectis, fortiter et crebrius sed baud profunde punctato ; elytris dense punctatis, scabriusculis ; coxis posterioribus fortiter, sed subobsolete punctatis ; abdomine obsolete punctato. Long. 62, lat. 3h m.m. This species is distinguished from Macrovatellus lateralis only by the rather more obscure colour, slightly broader elytra, and by the joints of the front and middle tarsi being just a little broader in proportion to their length : the distinctions between their structure in the two sexes being the same as in M. lateralis. South America. 439. 85. Macrovatellus sahlbergi, n. sp. — 6 Oblongo-ovalis, fere sine pubescentia, dense fortiter profundeque punctatus, piceus, capite antennisque minus diUite ferrugineis, elytris ad latera signaturis minus distinctis rufescentibus ; prothorace fortiter transverse, pone medium leviter angustato, ante basin evidenter transversim dej^resso, lateribus obsolete explanatis, opaco, crebre punctato ; elytris subnitidis, dense fortiter profundeque punctatis ; coxis jiosterioribus ruguloso-punctatis, abdomine indistincte punctato. Long. 62, lat. 3f m. In the male the front and middle tarsi are moderately broad, the third joint however being of the same width as the basal joint; the trochanters and the basal portion of the femora of the middle legs bear a ridge of dense yellow pubescence. The species resembles M. rudis greatly, but is readily distinguished by its broader and more transverse thorax, and the more shining, and more coarsely and distinctly punctured elytra. I have seen two males. South America. Found at Petropolis iii March, 1850, by Dr. F. Sahlberg, and sent me by his son, Dr. J. Sahlberg. 440. TRANS. BOY. DUB. SOC, M.S., VOI.. II. 2 I" •25 4 On Aquatic Cavaivorous Coleoplera or Dijtlsddce. 8G. Macrovatellusmarginalis,n.s}). — ? Oblongo-ovalis,fere sinepubescentia,densius punctatus, opacus, piceus, antennis pedibusque rufis,capite ferrugineo,elytris adlatera rufo-signatis ; prothorace quam his luulto angustiore, lateribus subsinuatis, angulis posterioribus acute rectis, anto basin sat distincte depresso, crebre punctato ; elytris dense minus argute punctatis, scabriusculis; corpore subtus obsolete punctato. Long. Q\, lat. Zl m.m. I have seen only two females of this species, they have the front tarsi long and slender, and when looked at beneath it is seen that the third joint is a little narrower than the first, and is more than twice as long as broad. At the side of the apical ventral segment there is to be seen only a narrow linear depression close to the edge of the elytron ; this character will distinguish the species from the three preceding species, for in them this depression is broader and more conspicuous and not linear. South America: Santa Rita, August, 1850, Dr. F. Salilberg. 441. 87. Macrovatellus mesicanus, n. sp. — i Oblongo-ovalis, fere sine pubescentia, d.ensius punctatus, opacus, piccus, antennis pedibusque minus Ifete rufis, capite rufo, elytris ad latera obsolete rufo-signatis ; prothorace brevi, elytris multo angustiore, lateribus sinuatis, angulis posterioribus acute rectis, ante basin sat distincte depresso, cr.ebre obsolete punctato ; elytris dense punctatis, scabriusculis ; coxis posterioribus, subobsolete ruguloso-punctatis ; abdomine crebrius subtiliter scabro. Long. 5j, lat. y m.m. The male has the front and middle tarsi moderately long and not very broad, and the middle trochanters and basal portions of the femora with a ridge of sliort not very conspicuous pubescence. I have seen only a single individual ; the species is allied to Macrovatellus marginalis, in the form of the thorax, and the linear impression at the side of the last ventral segment ; but it is considerably smaller, and the roughness or punctuation of the ventral segments is much more con- spicuous. Mexico. 442. 88. Vatellus haagi, Wehncke Stet. Zeit. 1876, p. 357. — Oblongo-ovalis, minus elongatus, fere opacus, fusco-rufus, elytris ad latera obsolete rufo-signatis, antennis pedibusque rufis ; capite anterius fere impunctato ; prothorace valde transverse, lateribus vix sinuatis, angulis posterioribus obtuse rectis, parce punctato, ante basin fortius transversim depresso ; elytris sat dense punctatis, scabriusculis ; coxis posterioribus subobsolete punctatis ; abdomine obsolete punctato. Long. 5 m.m., lat. 2i m.m. This species is allied to M. marginalis, and M. mexicanus, but is considerably smaller, and has the prothorax shorter and more sparingly punctured. I have seen On Aquatic Carnivorous Coleoptcra or Dijtiscida;. 285 but one individual which is a female ; and has the structure of the last ventral segment much as in the same sex of M. marginalis, the front and middle tarsi on the other hand are more slender. BrazU, (Weliiicke). 60G. 89. Macrovatellus ventralis, n. sp. — Oblongo-ovalis, parce pubescens, vix opacus, crebre punctatus, fuscus, uiarginibus minus distincte rufescentibus, antennis pedi- busquerufo-obscuris ; capite crebre a?qualiter punctato ; prothorace valde transverse, lateribus sinuatis, angulis posterioribus acutis, parce punctato, ante basin obsolete transversim depresso ; elytris elongatis, deplanatis, minus fortiter et dense punctatis, parcius pubescentibus ; coxis posterioribus sat crebre fortiter punctatis. Long. 6i m.ni., lat. 3^ m.m. The elongate and flattened elytra, the more obscure colour, tlie less dense and less scabrous punctuation of the elytra, and the different punctuation of the head characterize this species ; the punctures on the head show no diminution on the front part. The individual described has lost its tarsi, but is, I think, a male ; the front femora in the middle are subtuberculate, and near to the prominent part are densely ciliate (these characters exist to a slight extent in the other species but are more distinct in the present one) ; the ajjical venti'al segment is remarkably short. Brazil, (Wehncke). 607. I. 12.— Genus VATELLUS. Ventral sutures extremely deep ; anterior tarsi extremely elongate and slender. The only s^Decies known is very rare in collections. 90. Hydroporus tarsatus. Lap. Valellus tarsatus M.C. — Oblongo-ovalis, sub- tiliter sed evidenter pubescens, dense fortiterque punctatus, opacus, niger, antennis pedibusque piceis, femoribus dilutioribus, prothorace transverse, elytris multo angustiore, lateribus sinuatis, angulis posterioribus acutis, sat fortiter punctato ; elytris densius fortiterque punctatis, scabris ; coxis posterioribus fortiter profundeque punctatis ; abdomine sat fortiter punctato, suturis profundis ; tarsis a.nterioribus, elongatis, angustis, articulo 3° quam 2° vix angustiore. Long. 5, lat. 21 m.m. The tarsi differ but little in the sexes, but they are not quite so slender in the male as in the female ; the hind trochanters in the male are peculiarly globular and swollen. Cayeune. 443. 2P2 286 On Aquatic Carnivorous Colcoptera or DytiscidcB. I. VS.— Genus DEROVATELLUS. Mesosternum not much exposed between the prothorax and metasternuni : ventral sutures ordinary : size less than 4 m.m. Only one species is known ; it has occasionally been found in some numbers in the New World. 91. Vatellus lentus, Wehncke Stet. Zeit. ISiG, p. 357. — Oblongo-ovalis, subtiliter sed evidenter pubescens, fortiter punctatus, subnitidus, rufescens, capite, thorace, pedibus antennisque rufo-testaceis, elytris plus minusve nigricantibus ; capite parvo, oculis magnis ; prothorace trans verso, elytris angustiore, lateribus subsinuatis, fortiter punctato ; elytris crebrius fortiter punctatis ; coxis posterioribus fortiter punctatis ; tarsis anterioribus elongatis, gracilibus, unguiculis minutis. Long. 3f, lat. 2 m.m. In the male, the two basal joints of the front and middle tarsi are a good deal dilated, so that the third joint appears very slender in comparison to them ; in the female the three basal joints are all very slender and very compressed laterally. The species varies a little, more especially in the colour of the elytra, which are sometimes black, and vary between that colour and obscure reddish. South America, and the Antilles ; Santa Rita, August, 18.50, Sahlberg ; Santa Cruz, 10 to 17, 10, 1872, Van Volxem ; Porto Rico fide Wehncke. 444. II. 5. — Group L.\cco?niLiNr. Sciitellum quite concealed ; front and middle tai'si conspicuously five-jointed ; posterior tarsi with the hind margins of their joints lobed externally ; prosternal process acute behind ; wings of metasternuni very slender, arcuate ; size of the individual small. Only two genera are included in the Laccophilini, and one of these (Neptosternus) has yet but a single species, while the other (Laccophilus) has very numerous species. They may be very readily distinguished. Prosternal process simply acuminate ; hind angles of thorax ] LAOCOPIIILUS, rectangular or obtuse. j {vide p. 287). Prosternal process acutely tridentate ; hind angles of thorax 1 XEPTOSTEIiXUS, elongate, acute. | [vide p. 317). On Aquatic Carnivorous Coleoptera or Dytiscidce. I. IL—Geims LACCOPHILUS. Prosternal process with unispinose extremity; spurs of hind tibiae emarginate at their apex. Head ver}' short. The species* forming this aggregate are numerous and of extreme difficulty to study and discriminate. Tlie most useful and natural method of arrangement 1 can suggest at present is one based on the length of the prosternal process, and on the presence or absence of a coxal file ; and in order to further facilitate reference I have combined with this ai-rangement the fact whether the species are found in the New or in the Old World. The species seem to inhabit more especially the warmer parts of the world, and as I feel sure that not one-fourth of those existing are known to us, I do not think it worth while at present to try and effect a more detailed or truly natural classification of the species of the aggregate. The coxal file when present consists of a series of very fine ridges, placed on a segment of a circle, commencing near the middle of the body just where the coxal lines start from the extremity of the metasternum, and from this point they extend outwards and backwards so as to form a curved series of parallel furrows. The prosternal process has the extremity very slender, so that in the species where it is elongate it is not unfrequently broken off, but even in such a case its length can be estimated by that of the groove for its reception on the anterior portion of the metasternum. * In addition to those enumerated in the text, tlie following also belong to the genus : — Hydroporus inefBciens, Walk. (No. 1,382 huj. op.) ; Ceylon. Laccophilus adspersus, Boh. (No. 1,474) ; Caffraria. Laccojjhilus baeri, Regt. (No. 1,4T5); Manilla. Laccophilus cayennensis, Aube (No. 1,47G) ; South .\iiioriea. Laccophilus decoratus. Boh. (No 1,477); Manilla. Laccophilus flavescens, Motsch. (No. 1,478); Ceylon. Laccophilus hydaticoides, Regt. (No. 1,479); Manilla. Laccophilus Uneatus, Aube (No. 1,480) ; Mauritius. Laccophilus mexicanus, Aube (No. 1,481), 1 near No. 100; Mexico. LaccophUus orientalis, Aube (No. 1,482), ? near No. 161 ; Java. LaccophOus ornatus, Aub6 (No. 1,483), 1 near No. 118 ; South America. Laccophilus poecilus, Klug (No. 1,484); Egj-pt. Laccophilus proteus, Regt. (No. 1,485); Manilla. Laccophilus pumilio, Lee. (No 1,486) ; North America. Laccophilus quadrisignatus, Aube (No. 1 ,487) ; South America. LaccophUus rivulosus, Klug (No. 1,488), 1 near No. 148 ; Madagascar. Laccophilus strrehmi, Th. (No. 1,489), 1 No. 128 var. ; Finland. Laccophilus transversalis, Regt. (No. 1,490); Manilla. Laccophilus transversus, Motsch. (No. 1,491); Burmah. Laccophilus umbrinus, Motsch. (No. 1,492); Egypt. Laccophilus uniformis, Motsch. (No. 1,493) ; India. Laccophilus vermiculosus, Gei-st. (No. 1,494); East Africa. Laccophilus yvictse, Le Guill. (No. 1,495 ; Chili. 288 On Aquatic Carnivorous Coleoptera or Di/tisciJce. Group 1. — Prosternal process short ; male with a coxal file : species found in New World, Nos. 92 to 109. A. Species inhabiting the northern half of the New World. Nos. 92 to 104. B. Species inhabiting the southern half of New World. Nos. 105 to 109, N.B. — The coxal file is sometimes very fine and easily overlooked ; in some species it exists in the female as well as in the male, but then it is finer than in the latter sex. Certain species, of which the male is unknown, and at present placed in Group 2, may perhaps have to be transferred to this group. Group 2. — Prosternal process short ; no coxal file ; species found in New World. Nos. 110 to 127. N.B. — Of some species included here the male is unknown, and may possibly prove to possess a coxal file, and thus belong to Group 1. L. gentilis is only imperfectly known and as it appears to have a longer prosternal process than the allies, should perhaps be placed in Group 4. Group 3. — Prosternal process short, 6 with coxal file ; species inhabiting Old World. No, 128. Group 4. — Prosternal process short ; no coxal file : species inhabiting Old World, Nos. 129 to 135, Group 5. — Prosternal process with elongate extremity ; no coxal file : species inhabiting the New World, Nos. 136 and 137. Group 6. — Prosternal process with elongate extremity; no coxal file; species inhabiting the Old World ; the wing-cases without markings or with markings, but in the latter case the marks are never formed by undulating longitudinal lines. Nos. 13S to 145. Group 7. — Prosternal process with elongate extremity ; no coxal file ; species inhabiting the Old World, and with markings on the wing-cases consisting of more or less undulating longitudinal dark lines ; these lines maybe more or less interrupted transversely so as to leave pale fascite, or may extend the whole length ; in certain cases where these dark lines become very thick they are amalgamated or coalesce and then their undulating nature can scarcely be detected. No. 155 (Dytiscus variegatus) is the extreme of this case. Nos. 146 to 174. On Aquatic Carnivjrous Coleoptera or Bi/tiscidce. 289 Group I. A. 92. Dytiscus maculosus, Germ. Laccophilus maculosus M.C. — Ovalis, latiusculus, nitidus, testaceus, elytris fere impunctatis, pallidis, sed conspicue nigro-ornatis ; coxis posterioribus plus minusve infuscatis. Long. 5|, lat. 3i m.m. The markings of the elytra are more distinct in this species than in the allies ; their ground colour is pale yellow, but they are made dark by numerous minute dots, these dots are absent from some places which thus form yellow spots, while at the margins of these yellow spots the dark dots are condensed so as to form black marks ; the pale marks form a fascia at the base which is, however, much interrupted and rendered very irregular by longitudinal prolongations of the dark marks ; at the side of each elytron are four very conspicuous pale marks, the second from the base being largest, and the fourth is apical. In the male the four front tarsi are a good deal incrassate, and are furnished beneath with hairs bearing cupules at their extremities ; the hind coxa bears a curved series of fine lines or ridges commencing at the extremity of the metaster- num : in the female there are also traces of this file, but they can only be detected in this sex by a careful examination with a good glass. North America ; Lake Superior, Massachusetts, Hermit Lake, Pennsylvania, Georgia. (? South America ; Ega, Amazons). 528. The specimens supjiosed to have been found at Ega by Mr. Bates are a good deal narrower than those from North America, but I am unable to find any other difference : and I believe they are really from North America. 93. Laccophilus decipiens, Lee. M.C. — Ovalis, latus, minus depressus, nitidus, testa- ceus, elytris fere impunctatis, gequaliter fusco-irroratis, maculis paucioribus minus distinctis. Long. 5f, lat. 3 J m.m. The species is closely allied to Dytiscus maculosus (No. 92) but is rather larger, broader and more convex, and is readily distinguished by the less variegate elytra, from which the basal marks are entirely absent, and the marginal and sutural ones are much less conspicuous. The sexual differences are very similar in the two species. North America : California, Utah ; (Amer. lluss. teste Mannerheim). 529. 94. Laccophilus proximus, Say. M.C, — Ovalis, latiusculus, nitidus, testaceus, elytris fere impunctatis fuscis, signaturis pallidis minus distinctis. Long. 5^^, lat. 3 m.m. In the three individuals I have examined I can find no distinction from Dytiscus maculosus (No. 92) except the darker colour and more indistinct markings of the 290 On Ai^uatic Canticoivas Coleopteni or Dytiscidce. elytra, which however are so similar in the two that I am inclined to think them one species. Xortli America ; Nebraska, Sept., 1874 ; (Iowa, Texas, Florida, Illinois, Canada, fide Crotch). 530. 95. Laccophilus fusculus, n.sp. — Ovalis, minus latus et depressus, nitidus,testaceus, elytris fere impunctatis, fusco-irroratis, maculls paucioribus minus distinctis ; vertice capitis prothoracisque disco obscurioribus ; coxis posterioribus fuscis. Long. Si, lat. 3 m.m. Though I have seen only a single female of this species I think it distinct ; it is very much narrower than Laccophilus decipiens^ and appears intermediate between it and L. atristernalis Crotch. North America ; Nevada. 531. 9G. Laccophilus pictus. Cast. M.C. — Ovalis, latiusculus, minus depressus, sat nitidus, rufo-testaceus, capite thoraceque testaceis, illo vertice, hoc basi in medio nigris ; elytris fere impunctatis, nigris, maculis irregularibus nuraerosis testaceis. Long. 5, lat. 3 m.m. In the male of this species the marks forming the coxal file are not quite so deep and distinct as they are in Dytiscus maculosus (No. 92) : in the female the external edge of the elytra is dilated at a little distance before the apex, but this is also seen in some individuals of the same sex of Dytiscus maculosus. Mexico; Guatemala, (San Geronimo, Champion). 532. 97. Laccophilus insignis, n.sp. — Ovalis, minus depressus, sat nitidus, rufo-testaceus, capite thoraceque testaceis, illo vertice hoc basi in medio nigris ; elytris fere impunctatis, nigris, fasciis duabus transversis maxime irregularibus, maculisque versus apicem testaceis. Long. 5i, lat. 3i m.m. Closely allied to Laccophilus pictus, but larger and of more elongate form, and with the yellow marks on the elytra more extensive, so that a very irregular basal and a medial fascia is formed Ijy them. The tarsi of the male are thicker, and the marks forming the coxal file in the same sex are coarser and more conspicuous. North America, Texas ; (Lower California fide Crotch). 533. 98. Laccophilus fasciatus, Aubu, M.C. — Ovalis, depressiusculus, sat nitidus, testaceus, elytris impunctatis, minus distiucte fusco-irroratis, maculis lateralibus et apice testaceis, fascia lata ante apicem nigra ; prothorace basi in medio breviter lobato ; pectore ssepe infuscato. Long, vix .5, lat. 21 m.m. On Aquatic Carnivorous Coleoptcra or Di/tiscidce. 291 The markings in this species are similar in their general character to those of Dytiscus maculosus (No. 92), but are more indistinct, and there is a large dark mark before the extremity while the apex is entirely pale and unspotted : in the male there can be generally distinguished obscure basal marks, somewhat as in D. maculosus, in the female these are even more indistinct. The sexual characters are much those of D. maculosus ; the coxal file in the male is rather coarse, and is quite distinguishable in the female. o North America; Philadelphia; (Georgia, Indian Territory, Califoi-nia, fide Crotch). 534. 99. Laccophilus apicalis, Sharp, Ent. Mo. Mag. x, p. 53. — Ovalis, satconvexus et nitidus, testaceus, elytris nigro-suftusis, versus apicem late nigris, apice pallido, lateribus basique testaceo-signatis ; pectore utrinque parum obscuriore. Long, vix 5, lat. vix 3 m.m. This species is very closely allied to Laccophilus fasciatus, but is broader and more convex, and the dark colouration of the elytra has a greater extension; the base of the thorax is more produced in the middle : the male characters are much the same in the two species, the tarsi being much incrassate and the coxal file coarse ; in the female I am scarcely able to see any traces of the file. Central America; Nicaragua, Chontales; Guatemala, S. Geronimo, Champion. 535. 100. Laccophilus salvini, n. sp. — Ovalis, sat convexus et nitidus, testaceus, elytris nigro-sufl:usis, versus apicem nigris, apice pallido, lateribus basique testaceo- signatis; pectore abdomineque nigricantibus. Long. 4^, lat. 2| m.m. Closely allied to Laccophilus fasciatus, rather narrower and more convex, and with the under surface darker ; the front portions of the elytra are darker, so that the transverse black band is less distinctly defined in front ; the thorax in the middle of the base forms a slightly more acute angle. The male has the coxal file much finer than it is in the same sex of L. fasciatus ; in the female it appears to be entirely absent. The species is quite distinct from L. apicalis, by the darker colour, by the smaller size, by the finer coxal file ; none of the individuals have any trace of pale longi- tudinal marks on the basal pai-t of the wing-cases, and the apical pale spot is smaller than in L. apicalis. A variety occurs in which the hind legs are pitchy in colour. Guatemala. (Found by Osbert Salvin, Esq., at an elevation of 5,000 feet ; Guatemala city, Duenas, and S. Geronimo, Champion). 536. 101. Laccophilus americanus, Aube, Spec. p. 422. — Ovalis, sat latus, minus convexus, nitidus, testaceus, elytris impunctatis, fusco-irroratis, maculis irregu- laribus ad margines magis conspicuis testaceis. Long. 4i, lat. 2i m.m. TBANS. EOT. DUB. SOC, N.S , VOL. U. 2 Q 292 On Aq'iatic Carnivorous Cohoptera or Dyliscidce. This species is very closely allied to Dytiscus maculosus (No. 92), but is much smaller, and the markings of the elytra are much less distinct. It is a variable species in size, and the individuals from the United States are generally smaller than those from the Antilles. The sexual characters are much the same as in Dytiscus macu- losus ; the coxal file is rather coarse in the male, excessively fine in the female. North America and the Antilles ; Alabama, Louisiana, Texas, Mexico ; Antigua, Cuba. 537. 102. Laccophilus confusus, n. sp.— Oralis, breviusculus, parum convexus, nitidus, testaceus, elytris adspersim infuscatis, margine lateral! anterius apice siguaturisque minutis testaceis. Long. 4, lat. 21 m.m. This insect is much smaller than the preceding ones (L. americanus, &c.), to which it is allied ; the infuscate dots, though denser behind and ceasing abruptly before the apex, do not form a distinct band, the yellow marks formed by the absence of the dots from several places are of the same nature as in the allied species, and are principally distinct near the base. The male has the front and middle tansi much incrassate, and the coxal file although distinct is quite fine ; the female I have not seen. Although very similar to L. americanus the species is distinct by the much smaller size and finer coxal file in the male. Mexico. 1171. 103. Laccophilus terminalis, n. sp. — Ovalis, minus latus, sat convexus, nitidus, testaceus, elytris impunctatis, intricater nigro-signatis, signaturis pone medium fasciam transversam sat distinctam formantibus. Long. 4f , lat. 2l m.m. This species is larger than Laccophilus americanus, and of more elongate form, the yellow portions of the elytra arc more extensive being especially broad at the sides anterior to the dark band. Tt is quite as difficult to distinguish from Laccophilus fasciatus (No. 98), but it is narrower in fi'ont, more convex, with the black marks on the anterior portions of the elytra more developed, and the transverse posterior fascia less complete. The sexual differences seem the same as in the allied species. Nortli America; Texas, Belfrage. 538. 104. Laccophilus atristernalis. Crotch, Tr. Am. Ent. Soc. IV., p. 400. — Ovalis, sat convexus, nitidus, testaceus, elytris impunctatis, fere a3qualiter fusco-irroratis, pectore abdomineque nigricautibus. Long. ') m.m. lat. 3 m.m. The elytra in this species appear at first sight nearly unicolorous, this is caused by their being densely irrorated ^\■ith brownish dots ; the margins and apex are however paler, and there may be distinguished at the sides two extensions of the unspotted marks, forming indistinct lateral spots. On Aquatic Carnivorous Coleoptera or Dytiscido'. 29.^ It is very variable in size. The sexual characters seem quite the same as in the aUied species. I think it probable this will prove to be the Laccophilus mexicanus, Aube, (Spec. p. 420). California and Mexico. -539. Group 1. B. 105. Laccophilus chilen^is, n. sp. — Ovalis, minus convexus, latiusculus, subnitidus, testaceus, supra plus minusve vage fusco-suftusus, abdoniine pectoreque nigricanti- bus. Long. 5, lat. 3 ni.m. This is a rather large species, of sordid colour, owing to the upper surface beinw more or less suffused with fuscous, though not in a manner to give rise to any distinct pattern. I have seen only females, they have a very line coxal file ; which will no doubt prove to be more conspicuous in the male. The species seems closely allied to Laccophilus atristernalis, but is smaller and more depressed ; no doubt a sufficient; series would enable better marks of distinction to be detected. Chili. G19. 106. Laccophilus tarsalis, n. sp. — Ovalis, sat latus, subdepressus, nitidus, testaceus, prothorace anterius et posterius in medio, elytris, abdomine pectoreque fuscis ; elytris fere impunctati-^, signaturis testaceis. Long. 4, lat. 21 m.m. The elytra are irroratetl with fuscous dots, which leave a pale humeral mark and souie slender longitudinal marks between it and the suture, the lateral margin is very narrowly pale and on the middle has a pale spot, the apex also is dilute, and there are moreover some slender longitudinal pale marks, forming the rudi- ments of a transver.se fascia, some distance before the apex. The only individual I have seen is a male, it has the front and middle tarsi a good deal incrassate, and has a very distinct but short coxal file formed by deep impressions, about twelve in number. The apical ventral segment has its outline entire and uninterrupted. South America ; Parana. 5iC. 107. Laccophilus suftusus, n. sp. — Ovalis, baud elongatus, subdepressus, j^erni- tidus, testaceus, elytris fere impunctatis. castaneo-testaceis, signaturis irregularibus (quarum fascia basali conspicua) apiceque pallidis. Long. Si, lat. 2 m.m. The colour seems to be variable in this species ; the pale brown tint with which the elytra are suffused extends over their greater part, but leaves numerous irregular, pale, variable marks ; there is a more or less interrupted, basal, pale fascia, sometimes broken up into separate marks, and behind the middle there is a transverse fascia of longitudinal pale marks which are sometimes quite in- conspicuous : the dark colour extends quite to the sides, but leaves the apex pale ; 2 Q3 294 On Aquatic Carnivorous Coleoptera or Dijtiscidw. the hind coxse are infuscate to a variable extent. The male has a conspicuous coxal file of unusually coarse impressions. There is no sinuation of the apical ventral segment in either sex. South America ; Bahia. 542. 108. Laccophilus badeni, (Wehncke), n. sp. — Ovalis, latiusculus, sat convexus, minus nitidus, fusco-testaceus, pectore nigricante, elytris fuscis, prothorace lateribus elytrisque signaturis (quarum fascia subbasali flammulata conspicua) testaceis. Long. Al, lat. 3 m.m. There is in this species, near the base of the elytra, a conspicuous yellow band •which in two or three places is more or less completely divided by prolongations of the dark colour, and with the band is connected a very slender longitudinal pale •stripe near the suture ; there is also a pale mark at the side near the middle, and several irregular pale marks forming a transverse interrupted fascia in front of the apex, and the apex itself is pale. The elytra have rather a dull silky appearance. The male shows an excessively fine coxal file (it is as difhcult to see as that of the female Dytiscus maculosus) ; its apical ventral segment is not sinuate at the sides ; the front and middle tarsi are distinctly thickened. In the female the epipleurse are not inflexed near the apex, but become broader at some distance before the apex, and then rather abruptly narrow, so that when looked at from the side, the edge of the wing-case appears sinuate near the apex. Brazil, (fide Welincke). 552. 109. Laccophilus nigricans, u. sp. — Ovalis, angustulus, sat convexus, nigricans, antennis, pedibus, capite anterius, et prothoracis lateribus testaceis ; elytris fere impunctatis, lateribus anterius dilutioribus, ad humeros testaceis. Long. 31, lat. 2 m.m. The small size and dark colour of this species readily distinguish it. The only individual I have seen is a male, it has the front and middle tarsi a good deal incrassate ; there is a fine, indistinct coxal file ; the apical venti'al segment is not at all sinuate at the sides. Soutli America ; Parana. 553. Group 2. 110. Laccophilus quadrilineatus, Horn. Tr. Am. Ent. Soc. 1S71, p. 330. — Ovalis, elongatus, sat convexus, nitidus, testaceus, elytris Isevigatis, late irregulariter fusco-signatis, signaturis antice in lineas divisis ; prothorace basi medio acutius producto. Long. 6 m.m., lat. 3 m.m. In this species the marks of the elytra consist of some longitudinal linear marks. On Aquatic Carnivorous Coleoptera or Dytiscidce. 295 which are separate at the base but on the middle are coalesced, the sides are broadly yellow but beyond the middle a dark patch reaches the lateral margin, the aj^ex is quite pale. In the male the front and middle tarsi are much thickened : there is no trace of a coxal file in either sex. North America, Texas ; (Colorado fide Crotch). 540. 111. Laccophilus bifasciatus, Chev. M.C.— Ovalis, latiusculus, subdepressus, glaberrimus. pernitidus, testaceus, pectore, abdomine, prothorace medio elytrisque piceis, his fascia basali lata, altera pone medium apiceque pallidis. Long. 4, lat. 2\ m.m. I have examined six specimens of this species ; the sexes are very difficult to distinguish, the male having the tarsi almost as slender as they are in the female, the last ventral sesfment is however not so elonfjate in the former sex as it is in the latter. Cuba ; St. Domingo. 541. 112. Laccophilus simplex, n. sp. — Ovalis, nitidus, rufo-testaceus, capite thoraceque dilutioribus, elytris vix obscurioribus, impunctatis. Long. 3|, lat. 2 m.m. There is no coxal file in the male of this species, and the apical ventral segment is also similar, and without sinuation or truncation in either sex ; the male can only be distinguished from the female, by the slightly incrassate front and middle tarsi. Brazil, (Sauta Rita, August, 1850, Sahlberg). 543. 113. Laccophilus i-emator, n. sp. — Ovalis, minus latus ct convexas, nitidus, rufo- testaceus ; elytris fere concoloribus, creberrime subtilissime punctatis. Long, 4, lat. 2 m.m. This is a species very destitute of any salient points ; the elytra are without markings, and scarcely differ in colour from the other parts ; the punctuation on the front parts of the elytra can scarcely be distinguished as definite punctures. The only individual I have seen is a female, and has the apical ventral segment quite simply rounded. The species much resembles L. simplex, but is narrower in front, and has the elytra much less smooth. South America; Bahia. 554. 114. Laccophilus traili, n. sp. — Ovalis, sat convexus, nitidus, testaceus, elytris paulo obscurioribus, impunctatis, stria suturali sub-obsoleta. Long. 3f, lat. 2 m.m. 296 On Aqucxtic Carnivorous Coleoptcra or Dt/tiscidce. The male is without coxal file, but the last abdominal segment is deeply and broadly excised, while in the female it is excised on each side, the middle part forming a somewhat plicate projecting lobe. Although excessively similar to L. simplex, this species is very distinct from it by the sexual structure of the last abdominal segment. It possesses also on the elytra an obscure sutural stria, formed by nearly or quite coalescent impressed punctures ; the under surface is perfectly smooth, even the basal abdominal segments possess no visible scratches. South America ; Amazons, Montealagre, 1-13, 11. 1873, Professor Trail. 1121. 115. Laccophilus venustus, Chev. M.C. — Ovalis, fere angustus, subdepressus, pernitidus, loevigatus, testaceus, prothorace anterius in medio triangulariter infuscato, elytris fasconebulosis, fascia maculari subbasali signaturisque parvis testaceis. Long. 3f m.m., lat. 2 m.m. In this species the elytra are suffused with dark colour in an unequal or spotty manner, and there is a conspicuous pale fascia composed of united spots near the base, there is also a pale mark at the sides and a very broken fascia of pale marks before the apex. The only individual I have seen is the type from Chevrolat's collection ; it is a female and apjiears to be very closely allied to L. sufFiisus (No. 107), but is narrower, and the colouration is a little different. Cuba, (Coll. Brussels Mus.) ; (Mexico ?). 560. IIG. Laccophilus subsignatus, n. sp. — Ovalis, sat latus, minus convexus, perni- tidus, rufo-testaceus, prothorace basi medio elytrisque fuscis, his fascia subbasali aliaque ante-apicali et apice testaceis ; corpore subtus plus minusve infuscato. Jjong. 3f, lat. 2| m.m. The markings of the elytra in this species are rather vague and indistinct ; besides the two irregular fasciae the lateral margin is paler. The sexes are very difficult to distinguish, there being scarcely any incrassation of the male tarsi, and the ventral segment is simply curved at the sides, and similar in the two sexes. The species bears a very great resemblance to L. sufFusus (No. 107) so that I was long before I discriminated them ; the present species is however rather larger, has the prosternal process much longer, and the male has no coxal file. >South America, and the Antilles ; Venezuela. Guadeloupe. 571. 117. Laccophilus notatus, Boh. M.C. — Ovalis, sat latus et convexus, nitidus, testaceus, prothorace anterius in medio et posterius elytrisque fuscis, his fere impunctatis, fascia subbasali conspicua maculisque ad latera testaceis. Long. 4, lat. 2h m.m. On Aquatic Carnivorous Coleop/cra or Dytiscidw. 297 In. this species the elytra are suffased with dark colour, but there is a very- distinct yellow band near the base formed by united (or nearly united) transverse spots, there is a yellow spot close to the side about the middle, and generally another lateral mark extending more towards the suture between this and the apex. The species however is either a very variable one, or the specimens before me from several localities represent more than one species. There is a very slight oblique sinuosity in each sex, on either side of the middle of the last ventral segment ; the male has the front and middle tarsi rather thick : the female has an excessively fine groove on the under edge of the epipleura before the apex. There is no trace of coxal file in either sex. South America ; Monte Video, Urugiiay, Parana. 547. lis. Laccophilus fumatus, n. sp. — Ovalis, fere angustus, subdepressus, pernitidus, testaceus, el^^tris fuscis, impunctatis, fascia flammulata subbasali, macula laterali apiceque testaceis. Long. 4i, lat. vix 2^ m.m. In this species the thorax in the middle of the front and at the base is a little darker. The elytra owing to very diffused irrorations appear brownish ; they have a very distinct yellow band near the base, a yellow mark on the middle of the side margin, another small one on the middle of the suture, and some very minute indistinct pale marks elsewhere, the apex also being pale : the under surface is quite pale. The only individual I have seen is a female, and has the apical ventral segment rather long in the middle, and its outline uninterrupted by any sinuation. There is not the least trace of any coxal file. Brazil. 548. 119. Laccojihilus fractu.s, n. sp.— Ovalis, latiusculus, sat convexus, minus nitidus, rufescens, capite thoraceque dilutioribus, hoc anterius et posterius in medio, elytrisque fusci.s, his impunctatis, signaturis longitudinalibus testaceis. Long. 4|, lat. vix 3 m.m. The yellow marks of the elytra consist of a humeral spot and some longitudinal marks internal to it disposed so as to form an interrupted band, of a longitudinal mark near the suture, of some longitudinal marks behind the middle forming an obscure fascia, and of an obscure spot near the lateral margin about the middle, the apex also is paler. The only specimen I have seen is a female ; it has the epipleura quite simple : the last ventral segment is long, and has no sinuation at the sides. The coxas are infuscate in this individual. South America; Santa Rita, August, 1850, Sahlberg. 549. 120. Laf'cophilus vagepictus, n. sp. — Ovahs, subdepressus, minus nitidus. rufescens. 298 Gn Aquatic Carnivorous Coleojjtera or Dytisciche. thorace anterius in medio et postorius magis obscuro, elytris fuscis signaturis lono-itudi.iialibus testaceis. Long. 41, lat. 2i m.m. The marks of the elytra are rather indefinite, they consist of some longitudinal marks forming an ill-defined pale broad band, descending in an oblique manner from the shoulder towards the suture ; the apex is pale but in front of it the colour is darker than elsewhere ; there is also a pale mark near the side about the middle : the upper surface is rather dull, but the elytra show scarcely any traces of punctuation. The only individual I have seen is a female ; the epipleura bears 3^ groove on its under edge, which commences broadly and abruptly, and so causes the margin of the elytron when viewed from one side to appear a little dilated at a spot some distance before the extremity. The apical ventral segment is rather long, and without any sinuation of its outline. South America ; Santa Rita, August, 1S50, Salilberg. 550. 121. Laccophilus rotundatus, n. sp. — Ovalis, convexiusculus, minus nitidus, sub- sericeus, testaceus, prothorace in medio, pectore, abdomine elytrisque fuscis, his fascia subbasali signaturisque post medium testaceis. Long. 4, lat. 2i m.m. Near the base of the elytra there is a rather narrow, somewhat irregular, pale band, indistinctly interrupted at the suture ; there is also a pale mark at the side near the middle, and several large, coalescent, pale marks, forming a broad, flammulate mark behind the middle, and the apex itself is also pale. In the male, I can see no trace of a coxal file ; the front and middle tarsi are distinctly incrassate. The female differs in the simple tarsi; but very little in the structure of the epipleurse. The species is very similar to L. sufiusus (No. 107), but is much smaller. Brazil. G18. 122. Laccophilus bicolor, (Cast.) Aube, M.C. — Ovalis, sat latus, subdepressus, minus nitidus, rufescens, elytris fascia lata transversa fusca. Long. 4, lat. 2| m.m. The elytra in this species are quite -pale at the base and apex, and are broadly darker across the middle ; in the dark band there is an obscure pale spot near the margin ; I find in the individual examined only very indistinct signs of the second subapical band mentioned by Aube in his descri^ition. The only individual I have seen is a female, and has the epipleura nearly simple, and the apical ventral segment rather long, and without any sinuation. South America ; (Cayenne, Coll. Bouvouloir). 551. 123. Laccophilus undatus, Aube, M.C. — Ovalis, sat convexus, minus latus, nitidus, rufo-testaceus, elytris dense subtiliter puuctulatis fusco-testaceoque varie- gatis ; antennarum apice infuscato. Long. 4, lat. 2 m.m. On Aquatic Carnivorous Coleoptera or Dytiscidce. 299 The marks of the elytra in this species are distinct and complicated, hut vary- somewhat ; the basal portion of the elytra is pale, but has a dark spot near the shoulder and another near the suture, the pale basal portion is very irregular in form, and the dark spots in it are more or less connected by prolongations with the medial dark marks, at the middle of the side the dark part is encroached on by a pale spot, and there is a very irregular more or less interrujjted pale fascia beyond the middle, and the apex itself is pale. The margins of the dark portions are darker than their centres, the colour there beinof more dilute. The male has the front and middle tarsi rather distinctly incrassate, but has no coxal file. In each sex the apical segment is without sinuation at the sides. North America, Pennsylvania ; Amazons Valley : but there is doubt whether tliis latter locality be correct. 55-5. 124. Laccophilus obesus, n. sp. — Ovalis, latiusculus, sat convexus, pernitidus, supra creberrime sub-obsolete punctulatus, castaneus, capite thoracenue rufo-testa- ceis, hoc anterius medio obscuriore, elytris signaturis apiceque pallidis. Long. 4, lat. 2t m.m. The pale marks of the elytra consist of some large basal spots which form a transverse fascia, of a spot on the middle of the lateral margin, of a larger transverse mark between this and the apex, and the apex also is pale. The only individual I have seen is no doubt a male, though it possesses only very slight external distinctions, its front tarsi, and the apical ventral segment being nearly simple, though there is an excessively slight sinuation on each side of the middle of the latter. In the collection of the Brussels Museum there exists however a female from Minas Geraes , v/hich is either a variety of this species or a very closely allied one ; it has the apical ventral segment more elongate and without the least sinuation, and the epipleural fold shows a depression for some distance before the apex. South America, Caj-enne. .544. 125. Laccoi^hilus latipes, n. sp. — Ovalis, sat convexus, pernitidus, supra obso- letissime punctulatus, piceus, antennis, pedibus anterioi'ibus, capite, prothoracis lateribus elytrisque signaturis conspicuis apiceque testaceis. Long. 4, lat. 2| m.m. The species is closely allied to the preceding, but is darker in colour, with the upper surface less visibly punctulate, and the markings of the elytra (which are however quite the same in their distribution) very conspicuous. The pale colour at the sides of the thorax extends in a very indistinct manner across the middle. I have seen only two individuals, which are males, and show quite the same characters as L. obesus. South America, Parana. 545. TBAN$. KOT. DUB. SOC, N.S. VOL. II. ' E 200 On Aquatic Carmcorcus Cohoptcra or Dyiiscidce. 1 26. Laccophilus quadrivittatus, Aube., M.C.— Ovalis, minus latus, subde2:>ressus, pernitidus, Isevigatus, rufo-testaceus, thorace anterius in medio et posterius, ulytris- que summa basi iufuscatis, his fascia lata mediali nigro-fusca. Long. 3^, lat. vix 2 m.m. In this species, the broad yellow apical portion of the elytra is more or less infuscated across its middle portion, so as to give the appearance of a subapical yellow fascia ; the male has the tarsi but little thickened ; in this sex the apical ventral segment is rather more truncate than in the female, and appears slightly sinuate-truncate on each side. The species is a very smooth and shining one, and the oblique striae or scratches on the ventral segments are not conspicuous. Antilles, Porto Rico. 55 G. 127. Laccophilus gentiUs, Lee, ]\I.C. — Ovalis, angustulus, subdepressus, nitidus, rufo-testaceus, prothorace anterius in medio et posterius obscuriore, elytris sub- tiliter punctulatis, fuscis, vage rufo-signatis. Long. 3^, lat. 1| m.m. In this species the markings are ill defined ; there is on the elytra a more or less complete sub-basal pale band, and a spot on the middle of the side, and another subapical one, the apex also being pale. The sculpture of the elytra though very fine is distinct, and the scratches on the ventral segments are rather conspicuous. The male has the front and middle tarsi rather thicker than in the female. There is but slight sexual difference in the form of the apical ventral segment. A female specimen (from Cuba ?) in the collection of the Brussels Museum, is rather larger and shows some other slight differences, so that it may prove to be another species. Korth America, Louisiana. 557. • Group 3. 128. Dytiscus interruptus, Panz. Laccophilus ininutus, M.C. — Ovalis, sat latus, minus convexus, pernitidus, Irevigatus, testaceus, elytris plus minusve infuscatis, cum sio-naturis testaceis plus minusve indistinctis ; prothorace basi in medio brevius producto. Long. 45, lat. 2| m.m. In the male the front and middle tarsi are only very slightly incrassate ; the apical ventral segment is rather more truncate in the male than it is in the female and is very slightly sinuate on each side. There is a coxal file, composed of rather numerous strife, which are separated by wide but only very slightly elevated spaces. This file is about equally as distinct in the female as it is in the male. The species varies in colour, and when the infuscation of the elytra is very slight the yellow marks are of course less evident. The darker specimens come from Corsica, Sardinia, On Aquatic Carnivorous Colcoptera or Diji.i.scidce. 301 and the Canary Islands, (L. iaflatus, Woll.) The species also varies in breadth and size ; the larger and broader individuals are found only in the more southern parts of its area of existence, and were considered a distinct species by Aube, (L. testaceus). Europe (Corsica and Sardinia), Algeria, Canary Islands ; extends in the north as far as Lapland. 5G1, Group 4. 129. Laccophilus lewisius, Sharp, Tr. Ent. Soc. Lond., 1873, p. 52. — Ovalis, sat latus, minus convexus, nitidus, prothorace anterius in medio et in basi brevissime nigricante, elytris longitudinaliter fusco signatis, signaturis prgesertim posterius contluentibus, ad basin, ad latera et ad apicem areis esignatis ; antennis palpisque apicibus angustius fuscis ; prothorace basi in medio breviter producto. Long. 4|, lat. 2| m.m. In this species the reticulation of the upper surface is quite distinct ; the male has the front and middle tarsi much incrassate, and the last ventral segment more truncate than in the female. The markings of the elytra give this very distinct species a resemblance to Dytiscus maculosus, Germ. (No. 92), but Laccophilus lewisius is smaller and has no trace of a coxal file. Japan. 616. 130. Dytiscus obscurus, Panz. Laccophilus hyalinus, M. C. — Ovalis, sat angustus, minus convexus, nitidus, testaceus, antennis palpisque apicibus infuscatis ; elytris aliquando fusco-variegatis ; prothorace basi in medio minus breviter producto. Long. 4, lat 2| m.m. The male has the front and middle tarsi much incrassate. There is no trace of a coxal file in either sex. The species varies as to colour ; the elytra sometimes being infuscate in such a way as to leave a rather complicated set of pale marks. The species may always be at once distinguished from Dytiscus interruptus (No. 128), by the absence of the coxal file, and by the thicker male tarsi, as well as by its narrower form, more acute angle at the base of the thorax in the middle, and the infuscate apices of antennte and palpi. The apical ventral segment of the male is not truncate, and its form differs only very slightly from that of the female. Europe, (Corsica and Sardinia), Algeria and Syria; extends as far as Laiiland in the north. 5G2. 131. Laccophilus diflficilis. Sharp, Tr. Ent. Soc. Lond. 1873, p. 53. -Ovalis, sat latus, minus convexus, nitidus, testaceus, antennis palpisque apicibus infuscatis ; prothorace basi in medio minus breviter producto. Long. 4i, lat. 2i m.m. The male has the front and middle tarsi much incrassate. The species differs from the preceding, by its form, which is broader in the middle, and so appears more 2 R 2 302 On Aquatic Carnivorous Coleoptcra or Dijtiscidce. narrowed in front and behind ; the reticulation of the elytra is even more indistinct, but there are some very fine punctures visible, especially near the suture towards the extremity : the infuscation and variegation of the elytra is excessively reduced, and is only to be perceived by expanding them. Notwithstanding its near approach to Dysticus obscurus, (No. 130), I feel pretty sure that this is a distinct species. Japan ; China. .563. 132. Laccophilus Uobensis, Sharp, Tr. Ent. Soc. Lond. 1873, p. 53.— Ovalis, minus elongatus, sat convexus, nitidus, testaceus, antennis palpisque apicibus angustissime infuscatis, elytris sat distincte fusco-variegatis; prothorace basi in medio minus breviter producto. Long. 31, lat. 2i m.m. The male has the front and middle tarsi much incrassate. The species is extremely closely allied to the two preceding, but the smaller size and shorter form make it easy to be distinguished from them. Japan. 564. 33. Laccophilus sordidus, n. sp.— Ovalis, convexus, sordide testaceus, fere unicolor, antennis testaceis ; prothorace basi in medio elongato, acuto ; elytris sub- tiliter sed evidenter reticulatis, stria suturali punctorum. Long. 5, lat. vix. 3 m.m. The male has the front and middle tarsi distinctly a little incrassate ; the last ventral seo-ment is simple and entire in each sex, slightly longer in the male than in the female. The two individuals before me are in bad condition, and perhaps darker in colour than is natural ; there is no trace of any markings, and the species should be readily identified by its moderately large size and obscure colour, by the simple structure of the last segment in each sex, the very acutely angled base of the thorax, and by the reticulation of the elytra, and the obscure series of impressed punctures alonof the suture. Arabia, (El Hedjaz, Dr. Millingeu). 1173. 134. Laccophilus elegans, n. sp. — Ovalis, parum elongatus, subdepressus, nitidissimus, testaceus, elytris nigricantibus, signaturis magnis testaceis. Long. 4, lat. 2^ m.m. The yellow marks on the wing cases are in this species large and definite, there is a laro-e irregular transverse yellow band very close to the base, a yellow .spot on the lateral margin about the middle, another large irregular transverse band in front of the apex, and the apex itself is also pale. The species bears much resemblance to Laccophilus bifasciatus (No. Ill), from the Antilles ; it is remarkable On Aquatic Carnivorous Coleoptera or Dytiscidai. ;303 from the fact that the prosternal process is flatter and less compressed laterally than is usual. The only individual I have seen is a female ; it has the terminal abdominal segment entire and simple. Andaman Islands. 1172. 135. Laccophilus unifasciatus, (Wehncke), n. sp. — Ovalis, subdepressus, nitidus, testaceus, elytris castaneis, fascia sub-basali, maculaque ad latera testaceis ; prothorace basi in medio evidenter ^Jroducto. Long. 3, lat. It m.m. This is one of the smallest species of the genus, and is easily recognized by the dark elytra, with a narrow fascia near the base. In the male the hind margin of the apical ventral segment is rather obscurely truncate, and projects a very little in the middle ; in the female it is without sinuation or peculiarity of form : the male tarsi are but little incrassate. Australia, (Rockliamptou). 56". Group 5. 136. Laccophilus latifrons, n. sp. — Ovalis, minus latus et convexus, pernitidus, testaceus, elytris fusco suffusis, testaceo-variegatis, fascia flammulata basali cons^jicua. Long. 4, lat. 2i m.m. In this species there is on the elytra a yellow fascia near the base, reaching from the side margin to the suture, tliere is a yellow spot on the side about the middle. a very irregular interrupted pale fascia behind the middle, and the apex itself i.s rather pale, but is infuscate yellow : the dark colour is irregular, being formed by extremely bent and almost diffused lines, so that the spaces separating them are very indistinct. The male is more elongate than the female, has the front and middle tarsi a little incrassate ; and the apical ventral segment is truncate and distinctly produced in the middle so as to appear sinuate on each side. The female has the epipleura dilated some distance before the apex, tlie dilatation being so disposed as to form a plica or compressed fold. The apical ventral segment is so deeply sinuate on each side of the middle at the apex, as to appear trilobed, th^' middle lobe beinsf however much longjer than the lateral ones. South America ; Santa Rit:i, Augt. 1850, Salilbcrg. 558. 137. Laccophilus ovatus, n. sp. — Ovalis, minus latus et convexus, 23ernitidu8, testaceus, elytris fusco-suffusis, nunus distincte testaceo-signatis. Long. 3ri, lat. 2 m.m. The infuscation of the elytra is formed by very indistinct and waved lines, which indeed have almost tlie appearance of irroi-ations ; the pale spots left unencroacheJ on are small and indistinct, and also variable. The male has the front and middle 304 On Aquatic Carnivorous Coleoptera or Dytiscidce. tarsi a little incrassate, the apical ventral segment is truncate, but distinctly jiroduced in the middle and thus slightly sinuate on eacli side. In the female the epipleurc^ are simple, and the last ventral segment has a much produced middle lobe, and the portion on each side of this is nearly truncate. Brazil. 5.59. Group 6. 138. Laccophilus pellucidus, n. sp.— Latus, parum convexus, testaceus, unicolor nitidior, subtilius reticulatus ; prosterno basi in medio perparum elongate. Long, 5t, lat. 3t, m.m. This species is as long as L. luridus, but is quite different in form being very much broader in front and comparatively little convex. The base of the thorax in the middle is very little acuminate ; the hind tarsi are very broad. The male tarsi are not much incrassate, but their clothing beneath is more largely developed than usual, the palettes of the under surface being quite conspicuous, and placed on elono-ate hairs, and form four transverse series ; the apical ventral segment is much abbreviate, the hind margin rather deeply sinuate on each side, and very broadly rounded in the middle, The female I have not seen. South Africa ; Bedford district, Caffraria. 1 1 75. 139. Laccophilus luridus, Schaum, M.C. — Late ovalis, apice latius rotundatus, sat nitidus, testaceus, elytris vix obscurioribus, immaculatis. Long. 5J, lat. 3i m.m. The male has the front and middle tarsi a good deal incrassate ; the apical ventral seo-ment is truncate, but a little produced in the middle and sinuate on each side ; in the female the central lobe of this segment is elongate, and its hind margin is very slightly reflexed. The broad form, large size, and almost completely immacu- late elytra, make this species distinguishable at a glance. Eg}T)t. 5G5. 140. Laccophilus immundus, n. sp. — Ovalis, elongatus, sat angustus, minus nitidus, fusco-rufus, supra coriaceus, et in elytris subtilissime punctulatus. Long. 4i, lat. 2| m.m. I have seen but a single female of this very distinct species, the sculpture of it resembles that of Laccophilus undatus, (No. 123) the prosternal process is ho-svever elono-ate in the present species : the apical ventral segment is truncate and but little produced in the middle. Cape of Good Hope, (Capetown) from Castleiiaii's collection ; I do not feel quite sure that the label of the locality of this species is correct. 595. On Aquatic Carnivorous Coleoptera or Dytiscida. 305 141. Laccophilus sublineatus, n. sp. — Ovalis, convexus, subtilius reticulatus, nitidus, ferrugineus, fere unicolor, elytris dorso lineis fuscis, abbreviatis, rectis, tegre discernendis, stria suturali punctorum sat conspicua; prothorace basi in medio perparum elongate. Long. 4, lat. 2^ m.m. The convex form and obscure colour give this some resemblance to Laccophilus luridus, but it is not half the size, and the base of the thorax is less prolonged in the middle than it is in that species ; the lines of dai-ker colour on the elytra are so obscure that they are more easily overlooked than detected. I do not know the naale ; the female has the apical ventral segment obliquely sinuate on each side the middle, the middle of the hind margin being obtusely pointed. Ai-abia, (El Hedjaz) ; Mesopotamia : found by Dr. Millingen. 1174. 142. Laccophilus pictipennis, n. sp. — Ovalis, sat latus et convexus, nitidus, rufo- testaceus, prothorace anterius in medio elytrisque fuscis, his orgute testaceo- maculatis. Long. 4?, lat. 2i m.m. The yellow marks on the elytra are large and distinct in this species, and consist of a large humeral mark extending inwards and nearly joining a sutural spot, a mark on the side about the middle, and a very waved sub-apical band of nearly united spots, there is also a yellow mark at the apex, but the suture and extreme apex are fuscous ; there is also a longitudinal vitta extending backwards from the anterior sutural spot. The species is just about the size of Dytiscus interruptus, (No. 128), but is more rounded at the sides, and the markings of the elytra are nmch more conspicuous. In the male there is scarcely any incrassation of the tarsi, but the apical ventral segment is largely truncate, and is emarginate on each side, the two emarginations being not quite similar, the one on the right side being rather deeper than the one on the left side. In the female the apical ventral segment is not truncate, and is scarcely sinuate on each side. Arabia and Abyssinia, (El Hedjaz, Dr. Millingen). 5G6. 143. Laccophilus discretus, n. sp. — Rotundato-ovalis, convexus, nitidus, fusco- ferrugineus, elytris obsolete testaceo-maculatis, antennis testaceis, pedibus rufis; elytris stria suturali plus minusve conspicua. Long. 42, lat. 21 m.m. This species is of an infuscate reddish hue, with obsolete yellow marks on the elytra, these consist of an interrupted irregular basal band, very large at the shoulder, and of a second interrupted irregular band behind the middle, the apex itself is also more or less indistinctly pale, there is generally also a very indistmct narrow longitudinal stripe near the suture and connecting the two transverse bands. The sutural impressed stria seems always to be present though sometimes very indistinct; it appears as if formed by numerous approximate punctures. The male has the last ventral segment much truncate, and very slightly emarginate 30G On Aquatic Carnivorous Coleoptera or Dytiscidce. on each side of the middle, the emargination however is very slight especially on tlie left side. In the female the apical segment is much less truncate, but still it is a little abbreviated, and is scarcely sinuate on each side. Arabia, (El Hedjaz, Dr. Millingen). 1170. 144. Laccophilus wehiickei, n. sp. — Eobustus, ovalis, latus, sat convexus, nitidus, testaceus, elytris vage castaneo-saturatis, sed basi late pallidis. Long. 4i, kit. vix 3 m.m. In this species, the elytra are suffused with a darker colour in such a way as not to give rise to any well defined mark : a stripe along the suture is dark, the large dark cloud scarcely mixes with the sutural stripe, and leaves a broad space at the base quite i)ale, and though the limits of this cloud are very ill defined it does not extend either to the sides or ajiex. I am acquainted only with the female ; the apical ventral segment is elongate in the middle so that it is very oblique on each side, and has no siauation, it is a good deal compressed longitudinally in the middle towards the apex. Africa; Zanzibar. 620. i45. Laccophilus sianiensis, n. sp. — Ovalis, subdepressus, pernitidus, testaceus, elytris castaneis, ad latera et ad apiceni fasciaque subbasali lata testaceis ; l)rothorace basi in medio minus jiroducto. Long. \Vi, lat. 2 m.m. In this species the elytra are dark across the middle, and the dark colour invades in an irregular manner the apical yellow portion, so as to give rise to some appearance of a suba[)ical pale fascia ; the broad p.\le fascia near the base is very di.stiuct. The male has the front and middle tarsi but little incrassate : the hind margin of the a})ical ve"ntral segment is truncate, and a good deal sinuate on each side, the sinuation being most abrupt near the outer angles ; in the female the central lobe is very elongate, and the lateral angles are also distinctly projecting. i?irtm (Bangkok). 568 GUOCP 7. 146. Laccophilus grammicus, n. sp. — Ovalis, sat convexus, nitidus, testaceus, jarothorace basi in medio, elj'trisque sutura et lineis latis ad basin abbreviatis et ultra medium plus minusve interruptis, nigris. Long. 4, lat. 2t m.m. The elytra are marked with thick straight black lines, the edges of which, how- ever, are irregular, so as to form more or less distinct transverse connections between the lines ; the suture is black from beginning to end, the second line from the sucuro is longer than the other, and reaches nearly or quite to the base ; the On Aquatic Carnicorous Coleoptera or D>jlisddw. 3o7 lines are interrupted beyond the middle (exce^Dt the one next the suture), and where they reappear beyond the interruption, are more irregular and mixed together, and do not extend quite to the apex. The male has the front and middle tarsi a little incrassate ; the apical ventral segment is abbreviate, and its hind margin nearly straight, being scarcely produced in the middle and not at all at the sides. In the female it is a good deal longer in the middle than it is at the sides, so as to form a sort of indistinct middle lobe, but the lateral parts are not at all produced. Abyssinia. .569. 147. Laccophilus brevicollis, n. sp. — Ovalis, .sat convexus, nitidus, testaceus, pro- thorace anterius et posterius in medio, elytrisque sutura et lineis latis baud undulatis fere confluentibus, ante basin et ultra medium plus minusve interruptis, nigris. Long. 4, lat. 2^ m.m. This species i.s very similar to Laccophilus grammicus, but is smaller and the dark marks on the thoi-ax and elytra have a greater extension. The male is unknown to me ; the female has the apical venti-al segment elongate in the middle, but not forming a lobe, the sides forming very nearly a sioaple curve. Cape of Good Hope. 570. 148. Laccophilus lateralis, n. sp. — Ovalis, sat convexus, minus nitidus, rufo-testa- ceus, prothorace anterius et posterius infuscato, elytris nigro-suffusis, lateribus signaturisque paululum conspicuis testaccis ; abdomine pectoreque nio-ro-suffusis.. Long. 4, lat. 21 m.m. In this species the dark marks of the elytra are confluent so as to render the wing: cases nearly entirely dark except at the sides ; in some specimens there are traces of longitudinal pale marks. The male has the front and middle tarsi much incrassate, and the apical ventral segment truncate but distinctly sinuate on each side, the lateral angles projecting almost farther backwards than the middle part;, in the female the hind margin of the last ventral segment forms a slender, but rather elongate lobe in tlie middle, and the lateral angles are about similar to those of the male. Madagascar. 572. 149. Laccophilus luctuosus, n, sp.- — -Ovalis, convexus, nitidu.s, testaceus, pro- thorace anterius et posterius in medio infuscato, elytris fuscis, fascia sub-basali ad suturam anguste interrupta testacea ; pectore nigricante, abdomine fusco. Long. 3.S, lat. 2 m.m. A small and comparatively convex species ; the fuscous colour with \\hich the TRANS. ROT. DVD. SOC , U.S., VOL. II. 2 S 308 On Aquatic Carnivorous Coleoptcra or Dijtiscidce. elytra are suffused leaves, besides the fascia near the base, some small obscure variable marks behind the middle pale, and the dark colour scarcely reaches the ejiipleurfe. The male has the front and middle tarsi but little incrassate ; and has the apical ventral segment subtruncate, with a slight acuminate projection in the middle ; in the female this projection is more acute and longer, and the hind margin is rather oblique on each side, and close to the side is rather deeply sinuate. I have seen but one pair of the species, in rather bad condition. Madagascar. CI 7. 150. Laccophilus cyclopis, n. sp. — Ovalis, sat latus et convexus, nitidus, testaceus, elytris lineis hand interruptis sed ad latera disintegratis nigris. Long. A\, lat. 2r m.m. In this species the lines of the elytra are straight lines with irregular edges, and are not interrupted so as to give rise to any appearance of transverse pale bands ; the lines towards the sides are, however, more or less broken up into irregular irrorations. The yellow interstices are irregular being greatly broken up by the black marks especially near the extremity. In the male the front and middle tarsi are distinctly incrassate ; and the ajtical ventral segment is truncate, and but slightly sinuate on each side ; in the female it is deeply sinuate on each side, so that the middle part forms a very broad lobe. The species seems to be very variable in the dark lines of the elytra which are sometimes very black and approximate, though alwaj-s distinctly separated, while in other cases they are so diluted as to appear merely lines of irrorations. Southern Africa, (Graham's To^vn, Cape Town, Caffraria, N'Gami). 573. 151. Laccophilus coniplicatus, n. sp. — Ovalis, sat latus et convexus, nitidus, testaceus, elytris lineis undulatis, baud interruptis nigris. Long. 4i, lat. vix 2| m.m. In this species there is a small infuscation of the anterior and posterior margins of the thorax in the middle ; the lines of the elytra are very waved, and are evenly distributed, those near the suture not approaching in their character to straight lines ; b)^ this it is easily distinguished from the closely allied Laccophilus cyclopis, the ventral segments are more or less infuscate. In the male the front and middle tarsi are much incrassate, and the apical ventral segment is truncate but the middle part is evidently produced, so that the hind margin is distinctly oblique on each side ; in the female the middle part is more produced so that it forms a broad short lobe. Madagascar. 574. On Aquatic Carnivorous Coleoptera or Dytiscidce. 309 152. Laccophiliis posticus, Aube. M.C. — Ovalis, sat latus et convexus, iiitidus, rufo-testaceus, pi-othoraoe anterius et posterius in medio infuscato, elytris lineirs undulatis, baud interruptis, conflueutibus, nigris; abdoaiine pectoreque nigri- cantibus. Long. 4, lat. 21 m.m. This species is closely allied to I,accopbilus complicatus, but is much smaller, and has the black marks on the elytra more confluent, and the breast darker. Tiic male has the front and middle tarsi much inci-assate ; the structure of the last ventral segment so far as I can see in the very imjaerfect examples at my disposal is pretty similar in each sex to what it is in Laccophilus complicatus. Madagascar. 575. 153. Laccophilus irroratus, Aube. M.C. -Ovalis, sat latus, subdepressus, pernitidus, rufo-testaceus, prothorace anterius et posterius longius infuscato, elytris lineis undulatis nigris ; abdomine pectoreque nigricantibus. Long, il, lat. 2i m.m. In this species the infuscation of the thorax is extensive so that the marks on the front margin nearly or quite connect. The black marks of the elytra are very waved, and cover it pretty equally, except that at the base they are more or lessi abbreviated, so as to give rise to a more or less distinct appearance of a pale fascia there. In the male the front and middle tarsi are but little incrassate, and the last ventral segment is truncate, bat a little produced in the middle : in the female this segment has the middle part very broad, but it is sinuate on each side, althouy'h the side angles are not produced. Mauritius. 570. 154. Laccophilus medialis, n. sp. — Ovalis, subdepressus, pernitidus, testaceus, elytris in medio fascia lata fusca et ad apicem parcius fusco-irroratis. Lono-. 3r, lat. 2 m.m. In this species the dark marks of the elytra are so much abbi-eviated that there is a very broad pale fascia occupying the base, and only very slightly divided at the suture ; the apical jiortion of the elytra is broadly pale, but the dark marks again appear near the extremity in the form of some irregular irrorations. I have seen only the female, in which the sides of the last ventral segment have the appearance of being simply curved, owing to the middle part being very prominent, and sub- compressed laterally. Siam, (Bangkok). 577. 155. Dytiscus variegatus. Germ. Laccophilus variegatus, M.C. — Ovalis, angu?- tulus, minus convexus, nitidus, rufo-testaceus, prothorace anterius et posterius in 2 S 2 .310 On Aquatic Carnivorous Coleoptera or Dytiscidce. medio infuscato, elytris nigro-suffiisis, lateribus, fascia obliqua basaii alteraque ultra medium ad suturam interruptis, testaceis ; antennis extrorsum infuscatis. Long. 4, lat. 2| m.m. The marks of the elytra vary somewhat in this species, the pale marks on them being sometimes much reduced ; when the undulated dark marks are very confluent it is only by opening the elytra that the undulated yellow spaces separating them can be traced. The male has the front and middle tarsi a good deal incrassate, and the last ventral segment is much produced in the middle ; and in the female the form of tliis part differs comparatively little from the other sex. Europe ; Coraica. Not common, imd in tlie Xorth altogether wanting ; extends to the Soutli of England. 578. 156. Laccophilus flexuosus, Aube. M.C. — Ovalis, minus latus et convexus, nitidus, testaceus, prothorace anterius et posterius in medio brevissime infuscato ; elytris lineis flexuosis duplicatis minus confluentibus, ad basin ct ultra medium plus minusve interruptis nigris. Long. 4, lat. 2i m.m. This species is closely allied to Dytiscus variegatus. Germ. (No. 155), but is a little larger, and the dark colours of the upper surface are less extensive so that the lines on the elytra are more distinctly separated : these marks are however variable, being sometimes so much reduced that the elytra ajipear pale ; generally there are pale marks left at the base and before the apex similar to those of Dytiscus variegatus, but in some specimens the dark lines are very little interrupted, and then the pale spots alluded to are correspondingly reduced : the under surface is nearly always pale, but occasionally the breast and ventral segments are infuscate. The male has the front and middle tarsi a good deal incrassate, and the apical ventral segment is but little produced in the middle. In the female this segment is produced in the middle, and oblique, and a little sinuate on each side : but in this sex the sexual characters are instable, sometimes the form of this segment is different on the two sides, the sinuation being then very deep on the right side, while the left remains as usual ; the structure of the epipleurte of the elytra is subject to much variation in this sex, for in some individuals the inflexed portion of the wingcase becomes broader before the apex, and is then deeply impressed, while in other individuals, it does not depart from the form that exists in the male. The variation of the epipleurse appears to occur throughout all the area in which the species is found ; but the females with the peculiar unsymmetrical last ventral segment, I have only found to occur in the western part of the area of distribution. Widely distributed in Asia, from Mesopotamia to Japan : Persia, Northern India, Sumatra, Hong Kong, Formosa. 579. On Aquatic Carnivorous Coleoptera or DytiscidcB. 311 157. Laccopliilus ponticus, n. sp. — Ovalis, sat latus, minus convexiis, pernitidus, rufo-testaceus, prothorace anterius in medio dilute infuscato, elytri.s lineis undulatis nigris, ad basin maculatim interruptis. Long. 4, lat. 21 m.m. The specimens of this species at my disposal are in bad condition, and theii- colour therefore rather indistinct : the prothorax is only indistinctly infuscate on the front margin, and at the base there seems to be a small spot on each side of the middle. The lines on the elytra are thick lines extremely waved, not interrupted beyond the middle, but more or less broken near the base so as to cause there some spots. The male has the front and middle tarsi a good deal incrassate : and the apical ventral segment truncate but much produced and acumi- nate in the middle, so as to appear rather deeply sinuate on each side ; in the female the middle part of the segment is still longer, and the lateral oblique sinua- tions are not very distinct. Mesopotamia. .580. 158. Laccophilus obtusus, n. sp. — OvalLs, minus convexus, angustus, nitidus, testaceus, elytris lineis flexuosis ante basin desinentibus, ultra medium interruptis et versus apicem irregularibus fuscis. Long. 3|, lat. 2 m.m. The thorax is immaculate ; the elytra are marked with flexuous lines, which leave the basal part untouched, though near the shoulder and the suture they reach close to the base ; these lines in their front portions consist of pairs, but towards the apex are irregular and become more like irrorations, before the aj^ex they are interrupted by a pale space extending from the sides but not reaching the suture. The male has the front and middle tarsi much incrassate, and the apical ventral segment a good deal produced in the middle and sinuate on each side : in the female the middle portion of the segment is still more elongate. Singapore. 581. 159. Laccophilus derasus, n. .sp. — Ovalis, minus convexus, hand elongatus, vix angustus, nitidus, testaceus, elytris lineis flexuosis sat vagis, ante basin late desinentibus, ultra medium interruptis, fuscis. Long. 3l, lat. vix 2 m.m. This species is broader in front than Laccophilus obtusus. It has the prothorax immaculate ; the elytra marked with dai'k waved lines, which become dilute anteriorly and are altogether wanting on the basal portion, they also scarcel}' extend to the apex, and are interrupted beyond the middle by a pale space extend- ing from the sides. I have seen only the female, which has the apical ventral segfment forming a broad lobe in the middle and sinuate on each side much as in L. obtusus. Siatn, Bangkok. 582. 312 On Aquatic Carnirorovs Coleoptera or Dijtiscidce. 160. Laccophilus pcarvulus. Aube. M.C. — Ovalis, minus convexus, nitidus, testaceus, elytris disco lineis undulatis valde abbreviatis suturaque fuscis, abdomine obscuro. Long. SA, lat. 2 ni.m. This is a small species, comparatively little narrowed in front, and with the dark marks on the elytra reduced to some (about five) very short flexuous lines on the middle, so that they leave a considerable space at the base, and all the apical half immaculate, the suture however is dark for the greater part of its length ; and in some specimens these marks take a much greater development, so that there may be a subapical patch of small marks, and also some small irregular marks close to the base, the central batch of marks still remaining more or less distinct from the smaller basal and apical ones. In the male the front and middle tarsi are moderately incrassate and the apical ventral segment is a good deal produced in the middle and sinuate on each side ; in the female the apical portion of the segments forms a broader and more prominent lobe in the middle than it does in the male, and is a little more distinctly sinuate close to the outer angle. I am by no means sure that this is really the species described by Aube as L. parvulus. Sumatra. G21. 161. Laccoj^hilus, dispersus, n. sp. — Ovalis, sat latus, brevis, nitidus, testaceus ; elytris lineis flexuosis ante basin late desinentibus, ultra medium interruptis fuscis. Long. 3, lat. If m.m. This species is again closely allied to L. derasus, but is considerably smaller and less elongate ; the marks on the elytra are well defined, but similar to those of L. derasus. I have seen but a single male ; it has the front and middle tarsi distinctly incrassate, and the apical ventral segment is a good deal produced in the middle, and sinuate on each side. Siam, Bangkok. 583. 162. Laccophilus undulifer, Motsch. M.C. — Ovalis, minus convexus, nitidus, testaceus, elytris lineis duplicatis undulatis, minus abbreviatis fuscis, lateribus immaculatis ; corpore subtus leviter infuscato. Long. 3i m.m. lat. 1| m.m. In this species the lines of the elytra consist of distinct pairs, and nearly attain the base and the apex, the sutural one being however more abbreviate in front than the others ; these lines are quite wanting at the sides. I have seen only one individual in very bad condition ; it is a female, and has the a^jical ventral segment forming a very broad and very short projection in the middle, so as to be slightly sinuate on each side, but the outer angles do not appear to be projectino-. Madras, (Wehncke). 622. On Aquatic Carnivorous Coleojptera or DytiscidoB. 3] 3 163. Laccophilus clarki, (Wehncke), n. sp. — Ovalis, minus convexus, angustus, uitiJus, testaceus, protliorace anteiius et posterius in medio nigricante, elytris lineis undulatis fere integris. Long. 3|, lat. vix 2 m.m. This is a small narrow species, witli the dark marks on the elytra largely developed and distinct ; they consist of thick lines waved at their edges, and only separated by very narrow yellow marks, and are indeed here and there quite confluent ; near the base and beyond the middle in some places the black marks are somewhat reduced however so as to give rise to a slight appearance of a pale spot or two near the base and of a pale fascia beyond the middle ; the under surface is more or less infuscate. The male has the front and middle tai'si a crood deal incrassate. and the apical ventral segment somewhat produced in the middle and sinuate on each side ; in the female the hind part of the segment forms a broad much produced lobe, and the extreme sides are slightly prominent, so that close to the sides the hind mai'gin appears deeply sinuate. Australia ; Rockhampton, Gayndah, Moreton Bay. 581. 164. Laccophilus quadrimaculatus, (Wehncke) n. sp. — Ovalis, convexus, nitidus, testaceus, niger, capite, thorace, antennis pedibusque quatuor anterioribus testaceis, thorace basi breviter nigro ; elytris in medio macula parva laterali, aliaque post medium majore rufis, apice piceo, pedibus posterioribus piceis. Long. 31, m.m., lat ll m.m. I have seen only a single female of this easily distinguished species, the apical ventral segment is prolonged so as to be very oblique on each side. Australia (Wehncke). 623. 165. Laccophilus lituratus, n. sp. — Ovalis, sat latus, subdepressus, nitidus, testaceus, elytris fuscis, fascia sub-basali conspicua, maculisque duabus ad latera, testaceis. Long. 3, lat. If m.m. The elytra are in this species fuscous without trace of irroration or flexuous lines, there is a very conspicuous pallid fascia near their base, a pale spot at the side about the middle, and a pale s2)ot beyond this which extends further inwards towards the suture. The male I do not know ; the female has the last ventral segment elongate, not at all truncate, and the outline of its hind part at the side a simple curve. Siam. 592. 166. Laccophilus pulicarius, n. sp. — Ovalis, sat latus et convexus, nitidus, testaceus, abdomine elytrisque nigricantibus, his faciis duabus transversis, apiceque testaceis. Long, (elytrorum) 2 m.m. 314 On Aquatic C. 336.) HVPHYDRINI. ( Vide p. 370.) STERNOPRISCUS. (F«/ep. 384.) Hydroporini. ( Vide p. 389.) CELINA. (Videy). 487.) II. 6. — Group Hydrovatini. Prosternal process almost triangular, its posterior margin forming the base of the triangle, hind coxal cavities not contiguous, with broad coxal processes incised behind by a distinct coxal excision, external to which is a free, prominent, portion of the process (= extra-rimal lobe,) There are only two genera included in this family ; they may be readily dis- tinguished as below, one is an autogenus, the other is rich in species. Coxal excision longer in the longitudinal than in the transverse direction ; labrum visibly exserted. Numerous species. Coxal excision .shorter in the longitudinal than ] the transverse direction ; only the I labiiim visible. A single ] species. J in fringes of HYDROVATUS. {Vide p. 321.) QUEDA. {Vide p. 336.) On Aqnaiic Carnivorous Coleoptera or Dytiscidce. 321 I. 17.— Genus HYDROVATUS. Coxal excision longer in the longitudinal than in the transverse direction ; labrum visibly exserted ; length not exceeding 5 m.m. Numerous species, of short convex form, from various parts of the world.* 179. Hydrovatus clypealis. Sharp, Pet. Nouv. II, p. 61.— Brevissimus, minus dense et distincte punctatus, livide ferrugineus, coxis fortiter minus crebre punctatis. Long. 2i-2j, lat. li m.m. Mas, nitidus, clypeo medio leviter producto ettruncato, utrinque obsolete sinuato ; antennis crassis. Fern., subopaca, clypeo rotundato, antennis sat crassis. AntennEe short, joints 4-10 differing but little from one another, in the male transverse, in the female about as long as broad. In the male the basal joints of the front and middle tarsi are much dilated. This species is closely allied to Hyphydrus cuspidatus, but is rather smaller, and is readily distinguisbed by the difference of the antenna? and the sexual characters, by its less distinct punctuation on the upper surface, and the much less closely and regularly jJunctured coxae. Europe. South of England, (Portsmouth), France, (Kouen, Bourgogne, Landes), Algeria, Corsica, (Porto Yecchio, Reveliere), Sardinia. 1. 180. Hyphydrus cuspidatus, Kunze, Oxijnoptilus cuspidatus, JI.C. — Brevis, latus, rufescens, prothorace basi medio elytrisque obscurioribus, his fascia interrupta subbasali sat distincta alteraque obsoleta pone medium rufescentibus, versus suturam sat crebre et fortiter lateribus obsolete punctatis ; coxis posterioribus fortiter crebreque punctatis. Long. 2|-3, lat. If m.m. The male of this species has the basal joint of the front and middle tarsi dilated. * To this genus the following species, unknown to me, should probably be assigiaed : — Hydroporus carbonarius, Clk. (No. 1,349 huj. op.); Java. Hydroporus orientalis, Clk. (No. 1,411), near No. 200; China. Hydroporus portmanui, Clk. (No. 1,418); Mexico. Hydroporus pudicus, Clk. (No. 1,422), near No. 192; Java. Hydrovatus ferrugatus, Regt. (No. 1,450); Manilla. Hyih-ovatus hornii. Crotch (No. 1,451), near No. 221 ; Texas. Hydrovatus maculatus, Motsch. (No. 1,452) ; India. Hydrovatus obscurus, Motsch. (No, 1,453), near No. 193; Ceylon. Hydrovatus punctipeimis, Motsch. (No. 1,454) ; India. Hydrovatus rufescens, Motsch. (No. 1,455) : India. Hydrovatus seminarius, Motsch. (No. 1,456) ; India. Hydrovatus subrotundatus, Motsch. (No. 1,457) ; India. 322 On Aquatic Carnivorous Coleoptera or DytiscidcB. that of the middle foot more distinctly than that of the front one. The female is generally dull and not at all shining, while the male is shining, but individuals of the female occur similar in sculpture to the male. This species varies in colour, the spots on the elytra being sometimes distinct, while in other specimens they can scarcely be seen, and the upper surface becomes sometimes of a nearly unicolorous castaneous shade. It is possible that further specimens may show I have included more than one species under this name. A single female from Abyssinia, in the collection of the Genoa Museum, differs little from the European specimens, but I think a knowledge of the male would most likely show it to be a distinct species. Europe. (France, Belgium, Corsica, Sardinia, Germany, Dalmatia, Italy.) 2. 181. Hydrovatus flammulatus, n. sp. — Brevis, latior, rufotestaceus, prothorace basi in medio elytrisque fuscis, his fortiter puiictatis, margine externo iasciisque flaramulatis parum discretis, testaceis, coxis posterioribus fortiter crebreque punc- tatis. Long. 3 lu.m., lat. If m.m. The species is very similar to Hyphydrus cuspidatus, but is considerably broader, and the elytra are more coarsely jnmctured. The only individual 1 have seen has the upper surface shining, and is probably a male ; its antennae are more slender and a little longer, than in the corresponding sex of H. cuspidatus. The anterior tarsi do not appear to be dilated. South Africa, (Eastcourt, 27. 3. 1875). 1123. 182. Hydrovatus maculatus, n. sp. — Brevis, latus, nitidus, rufo-testaceus, pro- thorace basi in medio elytrisque fuscis, his signaturis testaceis magnis parum discretis ; versus suturam sat crebre lateribus obsolete punctatis ; coxis posterioribus fortiter crebreque punctatis. Long. 2f, lat. vix. 2 m.m. This species is excessively similar to such broadest specimens of Hyphydrus cuspidatus, (No. 180) as have the yellow spots on the elytra large and conspicuous ; it is however broader, and the male has the antennas slender. The four individuals before me are exactly similar to one another, all have the surface shining, and the basal joints of the front and middle tarsi appear to be without dilatation. Mesopotamia, (Dr. MilUngen). 1121. ] 83. Hydrovatus simplex, n. sp. — Brevissimus, sat latus, convexus, castaneus vel piceus, sat nitidus ; elytris versus suturam sat crebre et ibrtiter, lateribus obsolete jHinctatis ; coxis posterioribus fortiter crebreque punctatis. Long. 2i, lat. Is m.m. The male differs from the female by the basal joint of the middle tarsus being a little dilated ; the first joint of the front tarsus is also very slightly dilated. On Aquatic Carnivorous Coleoptera or Dytiscidte. 323 This species is extremely similar to the small dark varieties of Hyphvdrus cuspidatus (No. 180), but is rather narrower, and the front tarsi in both the sexes are more slender, and the basal joints of the front and middle tarsi are less dilated in the male ; the female seems to be nearly as shining as the male. The spotting of the elytra is more indistinct than in Hyphydrus cuspidatus. Europe. Corsica, M. Damry, Elmas, Sardinia, 9. 5. 73, Gestro. Malaga. 1.52. 184. Hydro vatus longicornis, n. sp. — Brevissimus, sed posterius conspicue attenuatus et acuminatus, ferrugineus, elytris crebre fortiter punctatis ; clypeo vix perspicue emarginato. Long. 2l m.m., lat. !§ m.m. Mas, antennis perelongatis, articulis 5-7 latioribus, clypeo utrinque sinuato. Fern., antennis sat elongatis, tenuibus, simplicibus. The species has no trace of spots on the elytra ; the male will be readily distin- guished by its very long antenna?, with the middle joints dilated. In the female the antennte are very much shorter than in the male, but still they are elongate, each joint being longer than broad. About the size of Hydrovatus clypealis (No. 179), but very distinct by the form of the front of the head as well as by the elongate antennae ; the coxae are wider than in H. clypealis and are more sparingly punctured, and their intra- rimal portions arc more depressed, so that a greater approximation of the base of the trochanters is possible ; the legs are longer and more slender than in H. clypealis, but the general structure of the undersurface except in these points is very similar. Egypt, (Dr. C. Millingeu). 3 185. Hydrovatus pictulus, n. sp. — Latus, brevissimus, convexus, nitidus, ferrugineus, supra fusculus, elytris evidenter rufo-signatis ; thorace crebre, elytris sparsim punctatis. Long. 2i, lat. 2 m.m. Scarcely longer than Hyphydrus cuspidatus (No. ISO), but a good deal broader, and so with the sides more curved, and easily distinguished from the other species by the very distinct red markings on the elytra. The antennae are very short, and rather stout, the joints being rather compressed, and transverse. The mare"in of the clypeus is quite distinct and is most evident in the middle, this part being rather produced and truncate. The under side is very similar to H. cuspidatus but the coxte are not quite so closely punctured. Madagascar, (coll. Bonvouloir, and Bi-ussels Museum, under the name of Hydroporus fasciatus Chev.) 4. 186. Hydroporus pustulatus, Melsh., Oxynoptilus cuspidatus, M.C. — Brevissimus, latus, convexus, alutaceus, fere opacus, ferrugineus, supra rufo-testaceus, prothorace TRAN9. ROT. DUB. SOC, N.S., VOL. II. 2 O 324 On Aquatic Co.rnivoroiis Coleoplera or Dytiscidtr. Iiasi medio elytrisque nigricantibus, his maculis niagnis rufis ; prothorace subtiliter fere obsolete punctato ; elytris crebre subtiliter, coxis crebre fortiter punctatis. Long. 21, lat. ll m.m. The male differs from the female only by the considerable dilatation of the basal joint on the front and intermediate tarsi. The spots on the elytra sometimes nearly disappear, and it is then of a more or less unicolourous castaneous hue. This species a good deal resembles the European Hyphydrus cuspidatus (No. ISO), but is really very distinct therefrom. It is rather broader, the thorax in the middle is longer, the surface is nearly ojiaque in both saxes, and the punctuation of the elytra is more even, being if anything lather finer at the suture than near the sides, whereas in Hyphydrus cuspidatus it is coarse near the suture but becomes quite obsolete towards the sides. In the male of the North American species the front tarsi are broader and flatter, (or less compressed laterally) than in the corresponding sex of the European species, and the dilatation of the basal joint of the front tarsus is a good deal greater. North America, (Michigan, Massachusetts). 147. 187. Hydrovatus brevipes, n. sp. — Brevissimus, latus, convexus, piceus, sub- opacus, antennis pedibusque rufis ; elytris sat crebre et vix subtiliter, coxis crebre fortiter punctatis. Long. 21, lat. vix H- m.m. The male is scarcely more shining than the female, but has the basal joints of the front and middle tarsi rather strongly dilated. This species is smaller, narrower and darker than Hyphydrus cuspidatus (No. ISO), and the punctuation of the elytra is a little coarser, more sparing, and less evenly distributed : the structure of the tarsi proves it to be undoubtedly a distinct species, for they are considerably shorter in H. brevipes, and the joints are of a difterent shape. North America, (California). 148. 188. Hydrovatus compressus, n. sp. — Brevissimus, latus, convexus, piceus, sub- opacus, capite prothoraceque rufescentibus, antennis pedibusque rufis, elytris sat crebre subtiliter, coxis posterioribus crebre fortiter punctatis. Long. 2j, lat. Ij m.m. This species is extremely closely allied to Hydrovatus brevipes, and is per- haps scarcely distinct therefrom, the punctuation of the upper surface however is finer, and the thorax is longer in the middle, so that it forms a more marked and distinct angle over the scutellum. I have seen only two males ; the tarsi in that sex differ but little from those of H. brevipes, but the front ones are scarcely so short and broad. North America, (New Orleans). 149. On Aquatic Carnivorous Coleoptera or Dytiscidce. 325 189. Hydrovatus caraibus, n. sp. — Brevior, convexus, nitidus, ferrugineus, elytris pectoreque fuscis, illis basi crebre fortiter, versus apicem obsolete parcissime punctatis. Long. 2?, lat. If m.m. This species is convex, and not very broad ; the front of the head is very dis- tinctly margined, the surface of the head impunctate. The thorax is at the base closely and rather coarsely punctured, elsewhere the punctures are indistinct. The elytra at the base are deeply and closely punctured, but the punctures become finer and more scanty behind so as to be altogether wanting at the apex ; they are dark in colour, without spots, but the apex is pale. The hind coxge are coarsely punc- tured. The individual described is no doubt a female as it has the tarsi quite small ; the wing-cases are, however, shining. It is larger than H. brevipes (No. 1 87), and distinguished from it by the closer punctuation of the base of the wing-cases, which also in the female of H. brevipes are dull. Guadaloupe. 1177. 190. Hydrovatus aristidis, Lep. Ann. Soc. Fr., 1879, p. Ixxxii. — Crebre punctatus, brevissimus, ferrugineus, elytris thoraceque infuscatis, hoc medio late rufo, illis obscure rufo-signatis ; prosterno medio ti'ansverso. Long. 2-2-, lat. if m.m. Mas, antennis deformibus, articulis intermediis dilatatis, 8-10 simplicibus, 11° iterum dilatato. Extremely similar at first sight to Hyphydrus cuspidatus (No. ISO), but with the punctuation of the upper surface rather closer and coarser ; the clypeus is margined, but the margin in the middle is more depressed than in H. cuspidatus, and therefore not so distinct. The front and middle tarsi are a good deal longer than in H. cuspidatus, and the process of the prosternum is transverse instead of triangular, the front part being truncate instead of acuminate : the punctuation of the coxae is less close and rather coarser. I have only seen a single specimen of this species, which I have no doubt is a male : the structure of its antennae is very remarkable : the first and second joints are simple, the third is broader than second, the fourth is broader than the third, very short, and slightly produced on the inner side, the fifth is extremely short and very broad, being much produced on the inner side, the sixth is very transverse, being just of the width of the fifth, but rather longer than it, the seventh is very laro-e and is dilated both on the outer and inner sides, eight to ten are simple and rather elongate, while the apical joint is again dilated, being about as long as, but not so broad as, the seventh. Egypt. 5. ^^^ 326 " On Aquatic Carnivorous Coleoptera or Dytiscidce. 191. Hydrovatus acuminatus, Motsch., M.C. — Brevis, sat latus, parce subtiliterque punctatus, testaceo-ferrugineus, supra magis castaneus, antennis tenuibus, simpli- cibus. Long. 2, lat. vix. H m.m. Very closely allied to Hydrovatus clypealis (No. 179), but smaller and narrower, and with the front and middle tibias, only about half as broad, the antennas more slender but scarcely longer, the hind coxte are also a little broader. If, as I suppose, I have both sexes before me, these only differ by the male being slightly more shining than the female. China, (Kiu Kiang, Lewis), Formosa, Celebes, Lombock, Sumatra. 6. 192. Hydrovatus fulvescens, Motsch., M.C. — Oblongo-ovalis, brevis, sat latus, valde nitidulus, castaneo-testaceus, sparsim subtiliter punctatus, antennis brevibus simplicibus ; coxis posterioribus sat fortiter sed sparsim subincequaliter punctatis. Long. If, lat. li m.m. A very small species, distinguished by its very shining surface, and sparse fine punctuation : the front tibiae are comparatively slender. I have seen only two individuals, which have the antennae short, the penultimate joints being not so long as broad ; the species is most allied to Hydrovatus acuminatus, but is considerably smaller, narrower, and less convex in form, more shining and more sparsely punc- tured. East India, sent by Wehncke. 450. 193. Hydrovatus fusculus, n. sp. — Brevis, sat latus, nitidus, confertim sat fortiter punctatus, castaneus, antennis tenuibus simplicibus ; coxis posterioribus fortiter crebre punctatis. Long. 2i, lat. l| m.m. This species is rather smaller and narrower than Hyphydrus cuspidatus (No. 180), and is of more obscure and uniform colour ; it has the front tibicB much thinner, and the antennae rather more slender. The sexual differences appear to be ex- tremely slight. Macassar, Jan., 1874, (Beccari), Formosa, China. Though the specimens from these different localities differ slightly, I cannot notice anything to distinguish them as species. 7. 194. Hydrovatus fasciatus (Wehncke), n. sp. — Brevis, sat latus, nitidus, confertim minus fortiter punctatus, ferrugineus, prothorace (lateribus exceptis), elytrisque piceo-castaneis ; antennis tenuibus simplicibus ; coxis posterioribus fortiter crebre punctatis. Long. £2, lat. 1§ m.m. Extremely similar to Hydrovatus fusculus, but slightly larger and more elongate, a little different in colour, and with the elytra more finely punctured. Australia, (Brisbane, Rockhampton). 446. . On Aquatic Carnivorous Coleoptera or Dijtiscidce. 327 195. Hydrovatus sumatrensis, n. sp. — Brevis, sat latus, nitidus, piceus subtus dilutior, antennis pedibusque testaceis, sat crebre minus fortiter punctatus ; antennis tenuibus simplicibus ; coxis posterioribus fortiter sed minus crebre subinsequaliter punctatis. Long. 2h, lat. iS, m.m. This species is not quite so clo.sely punctured on the hind coxae as H. tusculus, and H. fasciatus, to which it is extremely closely allied, and it is also darker in colour. I detect no distinct sexual differences. Sumatra, (ten individuals sent by Welmcke). 447. 19G. Hydrovatus ovalis (Wehncke), n. sp. — Ovalis, brevis, sat latus, minus con- vexLis, subnitidus, castaneo-ferrugineus, elytris basi sat crebre, subtiiiter punctatis ; antennis sat crassis, coxis joosterioribus dense fortiter punctatis. Long. vix. 2+, lat. 11 m.m. The antennae are rather stout, but are simple and not elongate. The surface of the thorax and elytra although little shining, is not evidently coriaceous ; the punctuation of the thorax is very fine, and that of the elytra is also rather fine. Australia, (Brisbane). 156. 197. Hydrovatus sordidus, n. sp. — Brevis, latus, nitidus, sat convexus, po.stice acuminatus, testaceo-ferrugineiis, elytris magis castaneis, confertim subtiiiter punctatis ; antennis tenuibus, simplicibus. Long. 2i, lat. If m.m. Very similar to Hydrovatus simplex (No. 183), hardly as large, slightly broader in proportion, rather less convex, with the punctuation of the upper surface finer, the autennte scarcely more slender and about the same length ; the front tibiae are rather more slender than in H. cuspidatus (No. 180), and the punctuation of the under surface is less dense and distinct. Also very similar to Hydrovatus fusculus, but larger, broader, and less convex, the outline more acuminate and prolonged in its hinder part, the front legs rather broader, and the antennae a little longer. I have examined twelve individuals, but find no differences by which I can with certainty distinguish the sexes. Mesopotamia, Egypt, Arabia (El Hedjaz). 8. 198. Hydrovatus humilis, n. sp. — Brevis, sat latus, convexus, vix nitidus, castaneus, elytris magis fuscis, sat crebre punctatis ; antennis vix tenuibus ; coxis posterioribus crebre punctatis. Long. 21, lat. It m.m. Very similar to Hydrovatus simplex, (No. 183), but rather narrower, not so shining, and with the elytra not quite so coarsely punctured, and the front tibiae rather more slender. The only two individuals I have seen have the tarsi quite 328 On Aquatic Carnivorous Coleoptera or Dytiscida. simple. 'Hie species is also closely allied to H. sordidus (No. 197), but is a good deal narrower, and the antennae are not so slender. Madagascar, (fide Wekncke). 153. 199. Hydrovatus elevatus, n. sp., — Subrotundatus, convexus, ferruginous, nitidus, crebre subtiliter punctatus, in elytris obsolete reticulatus ; antennis brevibus simpli- cibus, coxis posterioribus sat fortiter sed minus crebre punctatis, nitidulis. Long. 21, lat. Ism.m. I have seen only three individuals, which show me no sexual differences ; the antennae are short and rather slender, the joints from four to ten being about as long as broad. The species is a little longer than Uyphydrus cuspidatus (No. ISO) and a little more convex, the punctuation is less deep, and the anterior tibiae are slightly broader. Celebes, (Macassar, Jan., 1874, Beccari). 449. 200. Hydrovatus tinctus, n. sp. — Sat latus, nitidus, ferrugineus, supra fusco- castaneus, subtiliter vix crebre punctatus ; antennis tenuibus simplicibus ; elytris ad apicem sub-obtusis ; coxis posterioribus fortiter sed minus crebre subinaequaliter punctatis. Long. 2^, lat. \\ m.m. Rather smaller than Hyphydrus cuspidatus, (No. 1 SO) especially narrower and more parallel, darker in colour, more shining, more finely punctured; the coxae much more sparingly punctured ; the antennae rather shorter and a good deal thinner. The species is excessively close to H. sumatrensis, (No. 195) but is a good deal smaller, and has the punctuation of the elytra more obsolete. Siam, (Bangkok). 9. 201. Hydrovatus cribratus, n. sp. — Ferrugineus, latus, elytris fortiter crebriusque punctatis, prothorace basi subtiliter punctato, coxis parce punctatis. Long. 21, lat. li m.m. Mas, antennis elongatis, articulis intermediis latioribus, unguiculis anterioribus elongitis. Fem., antennis tenuibus, simplicibus, sat elongatis. Clypeus very distinctly margined, especially in the male, in which sex it is scarcely rounded, but is very slightly emarginate on each side. The antennae in the male are rather stout, and the intermediate joints, especially the sixth and seventh, are a good deal thicker than the others ; in the female the antennae are very slender. The punctuation of the elytra is close and very distinct. This species is closely allied to Hydrovatus longicornis, (No. 184) but is narrower. On Aquatic Carnivorous Coleoptera or DytiscidcB. 329 the antennae of the male are not quite so greatly developed, and the front of the head departs much less from the form of H. cuspidatus ; the punctuation of the elytra is closer and much more distinct. Africa, (Gaboon). 10. 202. Hydrovatus confertus, n. sp. — Brevissimus, latus, brunneus, subopacus, evidenter reticulatus, elytris crebre (fere dense) punctatis ; clypeo medio sub- emarginato. Long. 2t, lat. It m.m. Mas, antennis crassiusculis, medio leviter incrassatis. Fern., antennis tenuibus simplicibus. Smaller than Hyphydrus cuspidatus, very similar to H. clypealis (No. 179), even slightly shorter in proportion to its length ; the whole of the upper and under surface is covered with a fine distinct dense reticulation, which makes it opaaue ; the thorax bears scattered extremely fine punctures, and the elytra are more closely punctured than in the other species of the group, the punctures being rather deep and distinct but not coarse ; the punctures on the coxje are not dense. The margin of the clypeus is very indistinct, and the front of the clypeus appears a little emarginate in the middle. The antennae of the female are about as long as in H. cuspidatus, (No. 180) but considerably thinner than in the same sex of that species. The antennae in the male are a little thinner at the base and apex, but slightly thicker in the middle than in the male of H. cuspidatus. The male tarsi have the basal joint only slightly dilated, with the front claws not elongate, the tibiae are not quite so broad as in H. cuspidatus. Siam. 1 3. 203. Hydrovatus subtilis, n. sp. — Ferrugineus, latus, subtiliter reticulatus, sub- opacus, subtiliter sat crebre punctatus : clypeo obsolete marginato, subtruncato. Long. 2i, lat. li m.m. Mas, antennis crassiusculis, medio incrassatis. About as large as H. clypealis (No. 179) ; not so broad in the middle as is H. cuspidatus (No. 180), and so more parallel. Very closely allied to H. confertus, but rather larger, and more parallel in form, and the punctuation less close, and the reticulation of the surface less evident ; in the male the tarsi are a good deal broader and the antennae are a little longer and stouter, and there is an increase in the size of the joints towards the extremity, commencing at the sixth joint, the fifth and sixth joints are however only slightly enlarged, but the seventh and eighth are much more distinctly so, the ninth is a good deal narrower than the eighth. Siam. U. 330 On Aquatic Carnivorous Coleoptcra or DijtiscidcB. 204. Hjdrovatus acutus, n. sp. — Latus, subtiliter reticulatus, subopacus, in elytris crebre evidenter punctatus, testa ceo-ferrugineus supra leviter infuscatus ; clypeo indistincte marginato, subtruncato; coxis posterioribus minus crebre fortiter punctatis. Long. 22, lat. l5 ni.m. Mas, antennis longioribus ante medium incrassatis. Extremely similar to H. subtilis (No. 203), but with the incrassate joints of the male antennce different, the fourth and fifth joints being thicker than the others, while the sixth is a little and the seventh decidedly narrower than the preceding ones : the extremity of each wing-case is very slender and acuminate so as almost to form a spine. Celebes, (Jan., 1874, Beccari). Sumatra. 448. 205. Hydrovatus fractiis, n. sp. — Ferrugineus, latus, subnitidus, crebre fortiter punctatus, prothoracis lateribus subparallelis. Long. 2^, lat. 1| m.m. The mai'gin of the clypeus is extremely obsolete ; the elytra are closely and coarsely punctured, the coxre not closely, and not so coarsely. The size is nearly that of H. cuspidatus (No. 180) but the form is not quite so broad in the middle. The antennae are very slender and quite simple ; the front tibiee not quite so broad as in H. cuspidatus. The species may be readily distinguished from its allies by the diff'erence in the outline when looked at from the sides, it is then seen that this insect has the thorax a good deal more parallel-sided, and the elytra are more curved in and contracted at the shoulders, so that the lateral outline of the thorax and elytra is less continuous. T am not at all sure of the sex of the individual described, the front tarsi are broad, but the basal joint is scarcely so broad as the following one. Siam. 15. 20G. Hydrovatus crassulus, n. sp. — Ferrugineus, nitidus, crebre fortiter punc- tatus, convexus, sat latus, postice acuminatus. Long. 2h, lat. ll m.m. A very convex species, a good deal smaller than H. clypealis (No. 179). The antennoe are modei'ately long and stout. The thorax becomes but little broader towards the base, and the epipleural line of the elytra is much curved behind the shoulder. The coxae arc closely and coarsely punctured. Brazil, (Santa Rita, August 1850, Dr. E. F. Salilberg). 17. 207. Hydrovatus parallelus, n. sp. — Angustulus, subparallelus, minus convexus, testaceus, subnitidus, sparsim punctatus, ad apicem breviter acutus. Long. 2, lat. 1b m.m. • : On Aquatic Carnivorous Coleoptera or DijtiscidcB. 331 Antennae rather short, and stout. Clypeus extremely obsoletely margined. Thoracic punctuation very slight. Elytra rather sparingly but distinctly and evenly punctured. Ccjxce sparingly punctured. This species is intermediate in form between Hydrovatus and a small Hydroporus, but in its structure it departs but little from Hydrovatus clypealis (No. 179). Australia, (Rockhampton). 18. 208. Hydrovatus pumilus, n. sp. — Oblongus, minus couvexus et elongatus, sat nitidus, testaceus, sparsim subtiliter punctatus, ad apicem breviter acutus ; coxis posterioribus sparsim obsolete punctatis. Long. IJ, lat. 1 m.m. Though very closely allied to H. parallelus, this is a little smaller and decidedly shorter. It is the smallest species of the genus and the one in which the articula- tions of the hind legs are least separate. Sumatra, (two individuals sent by Wehncke). A specimen from " India " sent also from Welincke differs in being a little less shiuiog. 451. 209. Hydrovatus opacus, n. sp. — Latus, brevis, ferrugineus, evidenter reticulatus, subopacus, crebre fortiter puncfcatus ; antennis sat elongatis ; processu prosternali antice obtuso et apice leviter deflexo. Long. 2f, lat. Ij m.m. Mas, antennis crassiusculis, medio leviter incrassatis. Fern., antennis sat tenuibus simplicibus. Longer but not at all broader than H. cuspidatus, (No. ISO), and with closer and more regular, and rather coarser punctuation, and with the front tibiaj rather lono-er and more slender ; in the female the antennae are rather longer than they are in H. cuspidatus ; and in the male they are a good deal longer than in the female, and the middle joints (especially 4-6), are rather thicker than the others, the tarsi in this sex are also a good deal more dilated than in the other : the form of the point of the prosternal process distinguishes the species from H. confertus (No. 202), and its allies, which it greatly resembles. Australia, (Rockhampton). 12. 210. Hydrovatus obtusus, Motsch., M.C. — Testaceo-ferrugineus, minus latus, ad apicem minus acuminatus, crebre evidenter reticulatus, subtiliter sat crebre punctatus. Long. 2i m.m., lat. Ij m.m. Smaller and a good deal narrower than H. cuspidatus, (No. ISO), and much less acuminate behind, and with the punctuation i-ather finer and more evenly distributed. The large punctures on the coxaj are rather sparing and subobsolete, being but little impressed. The only specimen I have seen of this species is in the collection of the Brussels TOANf. ROT. DUB. SOC, N.S., VOL. H. J X 332 On Aquatic Carnivorous Coleoptera or DytiscidcB. Museum ; it was obtained from Chevrolat's collection, and is I believe an authentic individual received from Motschoulsky : a second specimen associated with it in Chevrolat's collection is a female of H. confertus. Hydrovatus obtusus much resembles H. confertus, (No. 202), but is narrower and more parallel, considerably less acuminate behind, and has the surfiice less densely and distinctly punctured ; it is also peculiar in form, the narrowing of the elytra commences nearer the apex than in the allied species, so that the form is broader and more truncate behind. India. IG. 211. Hydrovatus politus, n. sp. — Ferrugineus, nitidus, convexus, prothorace crebre subobsolete punctato ; elytris obsolete punctatis, seriebus punctorum sat distinctis, coxis fere impunctatis. Long. Zl, lat. 2l m.m. Clypeus almost without margin ; antennre slender and rather short. Thorax with numerous but indistinct punctures. Elytra with the punctuation very obsolete, except that each bears some moderately evident traces of series of longitudinal punctures, one of these series, along the suture, is only distinct towards the apex ; the second series is the most distinct, while the third and fourth are very indistinct. The hind coxae are almost impunctate, and the hind trochanters rather close to one another. This .species is very closely allied to H. castaneus, Motsoh. (No. 217), but is rather broader, and a little more acuminate behind ; the sculpture of the surface is more obsolete, but the sutural series of punctures is more distinct, and the antennae are rather shorter. Aiistralia, (Port Bowen). 11. 212. Hydrovatus nigricans, n. sp, — Nigro-piceus, nitidus, convexus, latus, dense fortiter punctatus, antennis pedibusque rufis ; trochanteribus posterioribus valde distantibus. Long. 4|, lat. 2| m.m. Antennae rather long, and slender. Thorax closely and distinctly punctured. Elytra rather coarsely and closely punctured, and with rudiments of one or two longitudinal series of punctures. Coxce rather closely but irregularly punctured. Middle and hind legs very widely separated. The only difference I see between the sexes of this species is that in the male the basal joints of the front and middle tarsi are broadly dilated. Madagascar. 19. 213. Hyphydrus uniformis, Fairm. Ann. Soc. Fr. 1869, p. 185. — Nigro-piceus, subopacus, latus, subrotundatus, convexus, dense fortiter punctatus, antennis pedibus- que rufis, illis crassiusculis. Long. 41 m.m., lat. 3 m.m. On Aquatic Carnivorous Coleoptcra or Dytiscidce. 333 Closely allied to H. nigricans, but broader and with the upper surface nearly opaque ; but readily distinguished by its shorter, broader antennse. I have seen only a single male, whose front and middle tarsi are distinctly dilated. Madagascar. 150. 214. Hydrovatus badeni, (AVehncke), n. sp. — Nigro-piceus, latus, convexus, dense fortiter punctatus, antennis pedibusque rufis. Long. 4?, lat. Ss m.m. Mas, nitidus, antennis sat elongatis et gracilibus, tarsis anterioribus et inter- mediis dilatatis. Fern., opaca, magis obsolete punctata, antennis paulo brevioribus, tarsis latius- culis, sed articulis basalibus haud dilatatis. Allied to Hydrovatus nigricans, (No. 212), but a good deal larger and with great differences between the two sexes. Madagascar. 151. 215. Hydrovatus compactus, n. sp. — Convexus, ferrugineus, nitidus, lateribus valde rotundatis, crebre sat fortiter punctatus ; trochanteribus j)osterioribus valde distantibus. Long. 3^, lat. 2i m.m. Antennre rather long and slender ; clypeus with a distinct and uninterrupted margin. Thorax closely and distinctly punctured. Elytra rather closely and coarsely punctured. Coxpe externally rather closely punctured. The general form is very convex and compact, and greatly rounded at the sides, so as to be much narrowed in front and behind. This species is closely allied to Hydrovatus nigricans, (No. 212), but is paler in colour and much smaller, it is even more convex and the elytra are less elongate. The individual described is a male but the tarsi are only about half as broad as in the (J of H. nigricans. In my collection there is a specimen which, from its resem- blance in form, I believe to be the female of this species, but it differs remarkably from the S by its sculpture, the whole of the upper surface being quite dull, densely reticulate, and with the sculpture obsolete, and the punctuation of the coxae is finer and more sparing. Africa, (Gaboon). 20. 216. Hydrovatus nigrita (Wehncke), n. sp. — Nigro-piceus, nitidus, convexus, latus, dense fortiter punctatus, antennis pedibusque rufis ; trochanteribus posterioribus bene distantibus. Long, fere 4, lat. 22 m.m. Extremely like Hydrovatus nigricans, (No. 212), but rather smaller and distinctly narrower, the antennse slightly shorter, the hind and middle legs not quite so widely 3X2 334 On Aquatic Carnivorous Coleojjtera or Dytiscidce. separated, and the hind legs rather more slender. In the male the basal joints of the front and middle tai'si are a good deal more dilated than in the female, but are not so broad as in the corresponding sex of H. nigricans. The only specimen I have seen from the Philippine Islands was sent me by Herr Wehncke, it appears to agree entirely with the Australian individuals. Australia, (Cape York, Rockhampton). PLUipiiines. 21. 217. Hydrovatus castaneus, Motsch., M.C. — Castaneus, nitidus, oonvexus, sat angustus ; prothorace crebre punctato ; elytris obsolete punctatis, seriebus puncto- rum sat distinctis, coxis parce obsoleteque punctatis. Long. Si, lat. 2i m.m. This species is very convex, and rather narrow in proportion. The clypeus is without distinct raised margin, and a good deal emarginate over the labrum ; the punctures on the thorax are distinct and rather dense about the middle : the punc- tuation of the elytra is more sparing and indistinct than that of the thorax. The hind trochanters are moderately widely separated, and the punctuation of the coxae is very scanty and rather indistinct. A specimen sent from Celebes (Macassar, Jan., 1874, Beccari) is rather more distinctly punctured, while one from Rangoon, (Wehncke), is smoother than the t3'pe. Ind. or., Burmah. 22. 218. Hyphydrus rufo-niger, Clark, M.C. — Nigricans, subtus piceus, pernitidus, oonvexus, angustulus ; prothorace crebre, subtiliter obsoleteque punctato ; elytris fere impunctatis, sed seriebus punctorum impressis distinctis ; coxis parce punctatis. Lonsf. 3i, lat. 2 m.m. The most shining and most indistinctly punctured, and comparatively the narrowest (with the exception of the little H. parallelus), of all the species. Very closely allied to Hydrovatus castaneus, Motsch. The antennce are rather long. The punctuation of the coxte though sj^aring is more distinct than in H . castaneus ; and the raised margin of the clypeus is not interrupted in the middle. Siam, (Bangkok). 23. 219. Hydrovatus picipennis, Motsch., M.C. — Piceus, subtus dilutior, nitidus, con- vexus, robustus, sat latus, prothorace elytrisque crebre subobsolete punctatis, illis seriebus punctorum parum distinctis; coxis parce punctatis. Long. 4, lat. vix. 2^ m.m. In this species, although the front margin of the head is but little distinct, it is more defined in the middle than at the sides ; tlie upper surface of the head is almost impunctate, the antennse are rather long and slender, their shortest joint (the tenth), being much longer than broad. The thorax has a distinct though rather ill-defined punctuation on the disc, but at the sides it is most obsoletely On Aquatic Carnivorous Coleoptera or Dijiiscidce. 335 punctured, in fact almost impunctate ; the elytra have a rather coarse, but very- little impressed and therefore obsolete punctuation ; the more internal of their series of punctures can be distinguished at the base only, and the more external series are extremely indistinct. The species is larger and broader than Hyphydrus rufo-niger, Clk. (Xo. 218), and has the elytra more punctate, but with the inner series of punctures on the other hand more indistinct. In form and sculpture it is nearer to Hydrovatus castaneus, JVIotsch,, but it is larger and darker, and the margin of the clypeus is less obsolete. It is the largest East Indian species here described. I have seen only a single individual in bad condition ; it is I believe a female. Siam, (Bangkok), Castlenau. 1153. 220. Hydrovatus bonvouloiri, n. sp. — Ferrugineus, latus, convexus, nitidus, pro- thorace crebre punctato ; elytris fortiter sat crebre punctatis ; coxis parcius distincte punctatis. Long. 3^, lat. 2^ m.m. Antennae rather long and slender, simple. Clypeus without margin, and very slightly emarginate over the labrum. Head completely destitute of sculpture. Thorax rather closely and somewhat finely punctured. Elytra with numerous scattered, distinct punctures. Coxte very shining and with very distinct but sparing punctures. India bor, (coll. Bonvouloir). 24. 221. Hydrovatus major, n. sp. — Rufescens, supra piceo-rufus, capite, thorace, elytrorum maculis dilutioribus ; elytris fortiter punctatis, anterius ad latera impressione longitudinali profunda. Long. 3f, lat. 2j m.m. This species is of broad form ; the head has very little punctuation, but the thorax is rather closely and distinctly punctured ; the elytra are strongly punctured, the punctuation being very coarse and close near the sides, and obsolete at the apex, a little behind the shoulder near the epipleura there is a deep elongate depression. The posterior coxse are^very coarsely punctured. The species is remarkable by the impressions on the sides of the elytra ; the colour of the upper surface is variable, and the red spots on the wing-cases are in some instances much'more conspicuous than in others. The sexual ditierences seem to be extremely slight , the antennae are slender and rather short, and in the male are slightly more serrate internally than they are in the female ; and in this latter sex the jDunctuation on the wing-cases seems to be just perceptibly denser than it is in the male. It is closely allied to Hydrovatus horni, Crotch. Duenas, Guatemala, G. C. Champion, 1879. 1122. 336 On Aquatic Carnivorous Coleoptera or Di/tiscidce. 1. 18.— Genus QUEDA. Coxal incision shorter in the longitudinal than in the transverse direction : only the fringes of the labrura visible; length G m.m. A single South American species. 222. Queda compressa, n. sp — Picea, nitida, convexa, lata, posterius angustata, et sat acuminata, elytrorum humeris rufis, antennis pedibusque rufo-testaceis ; dense sat furtiter punctata. Long. 5^ m.m., lat. 3^ m.m. Mas, antennis articulis 3-5, ceteris longioribus et latioribus. Fern., antenni.s articulis 3-5 ceteris longioribus haud latioribus. Of a compact and peculiar form, very broad in front and acuminate behind. Clypeus distinctly margined. Head finely and closely punctured. Thorax closely and rather finely punctured, the punctuation extending quite to the sides. Elytra closely, distinctly and evenly, but not coarsely punctured. Under surface distinctly punctured, the punctures on the hind coxse coarser than elsewhere, those on the ventral segments fine but numerous. A specimen in Bonvouloir's collection, labelled " fulvipes Reiche Columbia," is possibly a distinct species, being entirely black, and slightly longer. Brazil, (Santa Rita, August and Sept. 1850, R. F. Sablberg). 25. II. 7. — Group BiDESsiNi. The posterior border of the hind coxa? is completely soldered to the first ventral segment. The hind coxal cavities are separated and not j^rotected by the adpressed coxal processes. Tlie soldering of the hind coxa to the ventral segment is peculiar to these insects, and occurs in no otlier Coleoptera. Except for this the other characters of the group are much the same as in the Hyphydrini. { On the iindersurface of head \ IIETEEIl YDRUS, (vide p. tlie labrum is exserted. j" 337). Prosternal pro- cess attaining - the metaster- num. Middle coxoe conspicu- ously separated, pro- sternal process broad and short with obtuse hind margin. ^Middle coxm more ap- "| proximate, prosternal | process rhomboidal. ■ with acute termin- ation. ProsternalproccEsoblong. - Only the anterior border and fringes of labrum visibly exserted on under- side of the head. PACHYDRUS, {vide p. 338). Prosternal pro- cess notreach ing to the me- f tasternum. J _ \ DESMOPA CURIA, (vide p. j 340.) Coxal lines longer than pro- 1 j>jj)ESSUS, (vide p. 344.) sternal process. J ; v r / Coxal lines shorter than the ) IIUXELnTDRUS, {vide p. prosternal process. 3G9). ) TYXDALLHTDRUS, {vide / p. 370.) On Aquatic Carnivorous Coleoptera or Dijtiscidie. 337 I. 19.— Genus EETERHYDRUS. Labrum conspicuously exserted on under surface of head ; middle coxse rather widely separated ; prosternal process broader than long, its obtuse hind margin reaching the metasternum. Hind tibite straight, the basal portion not con- spicuously narrower than the apical one. A single species forms this genus. 223. Hyphydrus senegalensis, Aube, M.C. — Ovalis, subtus convexus, subopacus, niger, antennis rufis, pedibus piceis ; elytris sat crebre et sat fortiter punctatis ; pectore parce subtiliter, abdomine crebrius et niagis distincte punctato. Long. 6 m.m., lat. 3i m.m. Antennse moderately long and slender ; clypeus broadly rounded in front, with a sharply defined edge, indistinctly margined ; the surface of the head finely and rather sparingly punctured, and with no distinct depressions. Thorax very short and broad, but little longer in the middle than near the sides, the front angles, however, very produced, the lateral margins distinct, the surface rather finely, irregularly and sparingly punctured. The type of Heterhydrus agaboides communicated to me by M, Fairmaire has the surface dull and rather strongly punctured, and is perhaps a female ; if so the specimen in my collection, (for which I am indebted to Herr Wehncke), must be the other sex, for it is shining and but little punctate. On the other hand it is possible that these individuals may belong to difliercnt species : the latter individual, (the shining one), seems to agree exactly with a specimen from Senegal, now in the collection of Count Mnizech, who obtained it from Dupont's collection, it being one of the individuals on which Aube described his Hyphydrus senegalensis : this individual agrees exactly with Aube's description and measurement, but it does not accord very well with Laporte de Castlenau's few words of hurried description, nor with his measurements, (Et. Ent. p. 106), and it is possible that Laporte may have had some other insect in view ; as however bis description is insufficient for independent recognition, and we have no idea where his type was preserved, I have cited Aub^ as the authority for the species name, and the reference to Laporte de Castlenau should for the future pass unnoticed. Madagascar. 154. 338 Oil Aquatic Carnivorous Coleoptcra or Dytiscidw. I. 20.— Genus PACHYDRUS. Labrum concealed, only its front margin and fringes being visible ; middle coxae rather widely separated; prosternal process broader than long, its obtuse hind margin reaching the metasternum ; hind tibia3 straight, their basal portion not conspicuously narrower than the apical one. Five species from tropical America and the Antilles are included in this genus ;'"' they are very similar to one another in most respects ; the punctuation of their wingcases is much coarser than is usual in the Dytiscidse, and the species are best distinguished from one another by a reference to this character. 224. Pachydrus punctatus, n. sp. — Ovalis, nitidus, convexus, latus, piceus, capite thoraceque dilutioribus, antennis pedibusque rufo-testaceis ; prothorace superficie subintequali, fortiter irregulariter punctato ; elytris crebre, grosse punctatis, ]")unctis elongatis. Long. 4, lat. 2| m.m. Head somewhat finely, but quite distinctly and moderately closely punctured. Thorax with the surface obscurely wrinkled, and distinctly and rather coarsely punctured, the punctures being irregularly distributed, so as to leave small, smooth spaces. Elytra very coarsely punctured, the punctures being elongate in the longitudinal direction, this is most strikingly seen on their basal half, the punctua- tion at the sides is finer and dense, the humeral portions are paler than the rest. The outer portions of the hind coxse are somewhat coarsely j^unctured : the metasternum is only very obsoletely punctured. In this species and its allies I have not detected any external marks to distinguish the sexes. Brazil. (Santa Eita, September, 1850, Sahlberg; Rio de Janeiro). 48. 225. Pachydrus cribratus, n. sp. — Ovalis, subopacus, latus, brevis, piceus, capite thoraceque dilutioribus, antennis pedibusque rufo-testaceis ; prothorace superficie subinjEquali, crebre irregulariter punctato ; elytris dense, fortiter profandeque punctatis. Long. 3|, lat. 2^ m.m. This species is a good deal shorter than P. punctatus, to which it is very closely allied, but is very readily distinguished by the sculpture of the upper surface, which is closer, the punctures on the elytra show no elongation. Mexico ; Castleton, Q. U. S., N. America) ; Guadeloupe. 49. • The following two species' descriptions probably refer to insects of this genus ; Hyphydrus cayennensis Cast., (No. 1461 huj. op.) ; South America. — Hyphydrus globosus Aube, (No. 1403); Antilles. On Aquatic Carnivorous Coleoptcra or Dytiscidoe. 339 226. Hyphydrus obniger, Chev., M.C. — Ovalis, nitidus, convexus, sat angustus et elongatus, piceus, capite thoraceque dilutioribus, antennis pedibusque rufis ; prothorace crebre, irregulariter, subtiliter punctato ; elytris sat sparsim et subtiliter punctatis. Long. 4i m.m., lat. 2| m.m. This species is narrower than P. punctatus, and readily distinguished by the much finer punctuation of the elytra ; this towards the sides is a good deal closer and coarser than it is on their sutural portion. The species is very closely allied to P. obesus, but is more elongate, the punctuation of the thorax is coarser, while that of the elytra is rather finer (especially on the sutural portion), and less close and distinct. Cuba. 50. 227. Pachydrus obesus, n. sp. — Ovalis, nitidus, convexus, sat latus, piceus, capite thoraceque dilutioribus, antennis jDedibusque rufis ; prothorace irregulariter, sub- tiliter, sparsim punctato; elytris crebre vix fortiter punctatis. Long. 4, lat. 2f m.m. The surface of the thorax in this species is but little uneven, but the punctures are scattered in an irregular manner, and are quite fine, being not at all coarser than those of the head. Tlie punctures of the elytra are rather small, but rather deep and distinct. The species is slightly narrower in its form than P. punctatus, but is very readily distinguished therefrom by its punctuation. Venezuela, (Cumana). 51. 228. Pachydrus brevis, n. sp. — Ovalis, sat nitidus, latus, piceus, capite thoraceque dilutioribus, antennis pedibusque rufis ; prothorace superficie vix intequali, sparsim punctato; elj'tris crebre sat fortiter punctatis. Long. 4, lat. 2f m.m. This species is intermediate in form and sculpture between Pachydrus cribratus and Hyphydrus obniger, (No. 226). It is rather more elongate than Pachydrus cribratus, and is readily distinguished by the much less dense sculpture of the elytra ; it is a good deal less elongate than Hyphydrus obniger, and has the sculpture of the upper surface much coarser, deeper and closer ; it differs from Pachydrus cribratus very slightly, except in the sculpture, the distinction in this respect being however very conspicuous. Porto Eico. Antigua. 158. TRANS. EOT. DUB. SOC, N.S., VOL. II. 2 T 340 On Aquatic Carnivorous Coleoptera or Dijtiscidw. I. 21.— Genus DESMOPACHRIA. Front coxse almost reaching the front border of the prosternum ; prosternal process minute, rhomboidal, about as broad as long, its extremity sharply angulate • intercoxal process of metasternum connected with the mesosternal fork ; hind tibiae straio-ht, their basal portion not conspicuously narrower than the apical one. Thirteen species are included in this genus ; they are insects of peculiarly broad short form, the breadth being nearly as gi-eat as the length. Nearly all the species are at present rarely represented in our collections ; they are peculiar to the New World. 229. Desmopachria suturalis, n. sp. — Brevis, lata, subrotundata, sat convexa ferrugiuea, crebre sat fortiter punctata, elytris stria suturall distincta ; prothorace basi utrinque sinuato, angulis posterioribus acutis. Long. 2s, lat. 2 m.m. The head is rather narrow, the clypeus in front somewhat produced, the surface finely and moderately closely punctured. The thorax is distinctly punctured, the punctures along the whole breath of the basal portion being dense. The elytra are distinctly and closely punctured, and along the basal portion of the suture are marked by a stria formed by elongate punctures. The hind coxse, except in their hinder portion, are rather coarsely punctured ; the metasternum is impunctate. Brazil, (Santa Rita, August 1850, Sablberg). 52. 230. Desmopachria ovalis, n. sp. — Brevis, lata, subrotundata, convexa, ferruginea, crebre sat fortiter punctata ; prothorace basi utrinque leviter sinuato. Long. 21, lat. 1» m.m. Closely allied to D. suturalis, but only half the size, rather more convex, with the front and middle tarsi much less elongate, but stouter, and with no sutural stria on the elytra ; the sinuation of the base of the thorax near the hind angles is less distinct. Brazil, (Santa Rita, August 1850, Sahlberg). 53. 231. Desmopachria concolor, n. sp. — Brevis, lata, subrotundata, sat convexa, ferruginea, crebre vix fortiter punctata, prothorace basi utrinque leviter sinuato. Long. 2t, lat. \l m.m. Very closely alUed to Desmopachria ovalis but slightly broader and less convex, less acuminate behind, and with the punctuation of the elytra rather finer, and the posterior tarsi rather longer. South Amcrioi, (Uruguay). 56. On Aquatic Carnivorous Coleoptera or Dytiscidce, 341 232. Desrnopachria varians, Wehncke, Stet. Zeit. 1877, p. 151. — Brevis, lata, subrotundata, convexa, testacea, prothorace basi medio elytrisque nigro-signatis ; crebre fortiter punctata, elytris stria suturali impi'essa. Long. 2^, lat. if m.m. Closely allied to Desrnopachria suturalis (No. 229), but smaller and differently coloured ; the ground colour is yellow, and the base of the thorax is black, and the elytra are marked along the suture with black, and external to this have some large confluent, longitudinal black marks. This insect at first sight bears a good deal of resemblance to Dytiscus inasquahs, (No. 381), but it is broader and rather less convex, more finely punctured, and has the antennae shorter and finer. Brazil, (Bahia). .57. 233. Desrnopachria laevis, n. sp. — Brevis, lata, subrotundata, pernitida, im- punctata, castaneo-testacea, pectore abdomineque nigris. Long. If, lat. li m.m. The head is very broad and short, very gently rounded in front, and very finely margined. The thorax is slightly sinuate on each side near the hind angles, and is quite impunctate. The elytra are also impunctate, as is the under surface. Although this species is excessively similar to Desmopachria nitida (No. 236), and allies, it is readily distinguished by the dark colour of the under surface, and the polished, shining, almost absolutely impunctate upper surface. In this species the prosternal process takes two difterent forms; in one it is similar to that of Desmopachria nitida, viz., it consists of an anterior part, formed by two raised margins joined to form an acute angle in front, and a posterior part which projects from between these as an acute point ; in the other it is a bifid or furcate process ; the change is effected by the diminution of the central and posterior portion, the greater elevation of the raised sides of the anterior portion and their not being joined in front ; the character is I have little doubt truly a sexual one. Brazil, (Santa Rita, August 1830, Sahlberg). 59. 231. Desmopachria subtilis, n. sp. — Brevis, lata, subrotundata, sat convexa, ferruo-inea, sat crebre et fortiter punctata, prothorace basi utrinque leviter sinuato. Long, fere 2 m.m., lat. 1-J m.m. Very closely allied to Desmopachria ovalis, (No. 230), but a good deal smaller and with the punctuation more distant and rather finer : the form of the prosternal process is the same in both species, but I can scarcely think these two forms will prove to be but one species. This is one of two species confounded by Aube and described as one species under the name of Hydroporus convex us. Brazil, (Campos). 54. S^Jli2 ^On Aquatic Carnivorous Coleoptcra or DytiscidcB. 235. Hydroi'orus gran um, Lee, Proc. Ac. Phil. 1855, p. 294. — Breve, latum, sub- rotundatuin, sat convexum, Ditidum,rufo-testaceum; elytris versus suturam subtiliter punctulatis, lateribus apiceque cum prothorace et corpore subtus fere omnino Isvigatis. Long, is, lat. 1 J m.m. This species is very closely allied to Desmopachria nitida, Bab., but is a little smaller, and the punctuation of the upper surface is rather less close and distinct. I um not quite sure that the Brazilian specimens will prove to be conspecific with the North American ones,but the resemblance is excessive, and I have failed to detect any satisfactory distinctive character. North America, Brazil, (Santa Rita, Aug., 1850, Sahlberg). 153. 236. Desmopachria nitida, Bab., Tr. Ent. Soc. Lond. Ill, 1841, p. 17. — Brevis, lata, subrotundata, sat convexa, nitida, rufo-testacea ; elytris sat crebre, distincte sed subobsolete punctatis. Long. \l, lat. 1 m.m. The clypeus is broadly rounded in front with the margin fine, the surface of the head is impunctate. The thorax is only indistinctly punctured. The under surface is very nearly impunctate, the coxte exhibiting only a few obsolete fine punctures. 'I'he species is very closely allied to Hydroporus granum (No. 235), but is a little larger, and is a little less indistinctly punctured ; on the other hand it is decidedly smaller than Hydroporus convexus, and its punctuation is less distinct; it thus appears to be about intermediate between these two closely allied species. Brazil, (Rio de Janeiro). 55. 237. Hydroporus convexus, Aube, M.C. — Brevis, latus, fere rotundatus, sat convexus, ferrugineus, sat crebre subtiliter j^unctatus ; prothorace basi utrinque vix sinuato. Long. \l, lat. If m.m. The clypeus in front is broad and gently rounded, extremely finely margined ; the punctuation of the hind coxse is sparing and fine, but quite distinct. I have seen only one specimen from Brazil, and am by no means sure it will prove to be conspecific with the North American individuals, although I cannot at present point to any satisfactory distinctive character. United States of North America ; and Brazil, (Santa Rita, Sahlberg). 58. 238. Hydroporusbryanstoni,Clk.,M.C. — Brevis, latus, subrotundatus,satconvexus, pallidecastaneus, nitidus, elytris suturainfuscata; prothorace fere la^vi, basi utrinque i-inuato, angulis posterioribus acutis ; elytris crebre obsolete punctatis. Long. 21, lat. Ig m.m. Head with rather sparing and fine, but quite distinct, punctures. Thorax with only some indistinct punctures at the base in the middle. Elytra with numerous On Aquatic Carnivorous Coleoi^teixi or Dijtiscidce. 3^3 fine punctures, which are distinct on the sutural portion, and more obsolete towards the sides. Under surface impunctate and very shining. Also in this species the prosternal process takes two forms, in the one it is rhomboidal with the margins raised, and in the other a deeply bifid process. Brazil, (Bahia). (Mexico, _/rcZe Clark). 60. 239. Hyphydrus mendozanus, Steinheil, Atti. Soc. Ital. Sci. Nat. XII, p. 249. — Brevis, latus, sat convexus, ferruginous, vix nitidus, dense sat fortiter punctatus, prothoracis angulis posterioribus acutis. Long. 23, lat. if m.m. Closely allied to Desmopachria suturalis (No. 229), and D. ovalis, but distin- guished by the much denser punctuation ; there are only very indistinct indications of a sutural stria, the sinuation of the base of the thorax on each side is close to the hind angles, and is not very distinct, because the side of the thorax is a little depressed. The hind coxae are coarsely and deeply punctured. I am indebted to Herr Steinheil for the only specimen I have seen of this species. South America, (San Carlos). 78. 240. Hydroporus latissimus, Lee, M.C. — Latissimus, brevis, nitidus, sine pubes- centia, crebre sat fortiter punctatus, ferrugineus, prothorace basi infuscato, elytris testaceis, sutura late irregulariter maculaque externa nigricantibus ; clypeo acute marginato, j^rothorace utrinque plica curvata ; elytris stria suturali sat distincta, lateribus foveolatis ; coxis posterioribus fortiter punctatis. Long. 2, lat. ]f m.m. The fovea of the elytra is placed quite at their edge so that it may easily escape notice. California. 170. 241. Hydroporus dispersus. Crotch, Tr. Am. Ent. Soc. IV, p 358. — Latissimus, brevis, nitidus sine pubescentia, crebrius sat fortiter punctatus, ferrugineus, prothorace basi infuscato, elytris testaceis, sutura signaturaque externa nigris ; prothorace utrinque plica curvata ; elytris stria suturali distincta ; coxis posteriori- bus sparsim sat fortiter punctatis. Long. 2, lat. 1| m.m. Very similar in form to Hydroporus latissimus, (No. 240), but readily dis- tinguished by the more finely and densely punctured thorax, the absence of fovea on the elytra, and the less extent of the dark markings, and the less distinctly punctured coxae. It also a good deal resembles D. varians, (No. 232), but is shorter and broader, and has the punctuation of the coxae less developed than that species. California. 171. 344 Ori Aquatic Carnivorous Coleoptera or Dijtisci'a'. I. 22.— Genus BIDESSUS. Prosternal process longer than broad, parallel-sided, but with a more or less acute extremity which attains the metasternum ; intercoxai process of metasternum not attaining the mesosternal fork, so that when the prothorax is taken away it may be seen that the middle coxfe touch one another ; posterior tibire with the basal portion much more slender than the apical one. Cosal lines longer than prosternal process. These insects are of small size, (2 or 3 m.m. long.), and are found in most parts of the world. More than 80 species are included in this genus * ; this renders it necessary that an arrangement of the descriptions should be made to facilitate reference ; and in order to do this as naturally as possible, I have separated from the bulk of the species four natural groups, and left together the remainder of the genus in one group, which I have artificially divided into two sections according to whether there is present or not a sutural stria on the wing case. This grouping may be thus tabulated : — Group 1. — Head with an even, distinct, raised front margin : in the other gi'oups (except in Nos. 256 and 257) the head is without a definite margin. Species Nos. 242 and 243. Gkoup 2. — Thorax with a minute basal plica or impression, which is not in the least continued on to the elytra ; apex of elytra very acuminate. Species 244 to 246. * Besides these eighty species, the following descriptions may, (with the exception of the first of them), be assigned with considerable certainty to the genus : — Hydrogly]ihus flaviculus, Motseh. (No. 1,335 huj. op.); Ceylon. — Hydroponis adumbratus, Clk. (No. 1,338), near No. 308 ; Mexico. — Hydroponis amandus, Lee. (No. 1,339), Group 5 B. ; North America. — Hydroporus angularis, King. (No. 1,340) ; Nubia. — Hydroponis atomus, Eegt. (No. 1,342), ? near No. 307; Manilla.— Hydroponis charlotti, Clk. (No. 1,350), ?=No. 318; Mexico.— Hydroporus elegantuliis, Boh. (No. 1,36G), 1 near^No. 252 ; Caffraria. — Hydroponis emiliauus, Clk. (No. 1,3G7), ?=No. 318; Mexico. — Hydroponis evanescens. Boh. (No. 1,308); Caffraria. — Hydro- ponis fryi, Clk. (No. 1,372),? near No. 256; Mexico. — Hydroporus intirmus. Boh. (No. 1,385), near No. 269 ; Caffraria. — Hydroporus magensis, Clk. (No. 1,396) ; Mexico. — Hydroponis nico- baricus, Redt. (No. 1,403) ; Nicobar Islands. — Hydroponis obscurus, Bab. (No. 1,407), ?=No. 313 ; Brazil. — Hydroponis pseudo-geminus, Regt. (No. 1,420) ; Manilla. — Hydroponis seminulum, Lee. (No. 1,431), 1 Group 2 ; North America. — Hydroporus subtUis, Lee. (No. 1,436), Group 5, B ; North America. — Hydroporus tetragrammus, Hoch. (No. 1,441), near No. 270 ; Caucasus. On Aquatic Carnivorous Coleoptera or DytiscidcB. 345 Group 3. — Short broad species without pubescence, but with a tuost remarkably- sculptured surface, the punctures on the under surface being especially large, the plica at the base of the thorax is continued on to the elytra in so conspicuous a manner that it forms a sort of elongate- carina extending half the length of the wing cases. Species 247 to 254. Group 4. — Hind coxae not longer than broad ; surface not entirely glabrous, plica OQ elytra not extending one-half of length of the wing cases ; under surface with an extensive development of moderately coarse punctuation. Species 255 to 268. N.B. — The species placed at the end of this group connect it with the following one. Group 5. — Hind coxpe longer than broad, under surface with but little coarse punctuation, apex of elytra but little acuminate ; elytra with a basal plica, which is continued (except in two species, Nos. 291 and 292), on to the base of the elytra either as a short punctiform impression or as a distinct line. Species 269 to 325. This group is further sectionized thus : — A. Each wing case provided with a distinct sutural stria. Species 269 to 292. B. Wing cases destitute of a distinct sutural stria. Species 293 to 325. Group 1. 242, Hydroporus cribrosus, Schaum, M.C. — Ovalis, brevis, latus, convexus, elytris creberrime fortiter punctatis, vix nitidis ; pectore crebre sequaliter fortiter punc- tato. Long. 23^, lat. ih m.m. Egypt, (Cairo). 98. 243. Bidessus migrator, n. sp. — Ovalis, brevis, latus, convexus, elytris crebre fortiter punctatis, subnitidis ; pectoris lateribus fortiter, medio obsolete, punctatis. Long. 2, lat. It m.m. Very closely allied to Hydroporus cribrosus, Schaum, but rather narrower, and with the punctures on the elytra not quite so close, and slightly coarser : the punc- tures on the hind coxae are finer, and those on the middle of the sternum much finer than in the Egyptian species. Australia, (Rockhamptou). 9P. 346 On Aquatic Carnivorous Coleopiera or DijtiscidoB. Grocp 2. 244. Hydroporus apicatus, Clk., M.C. — Brevis, latus, ovalis, posterius valde acuminatus, castaneo-testaceus, nitidus, glaber ; prothorace basi utrinque strlola subtili ; elytris crebre subtiliter sed distincte punctatis. Long. It, lat. 1 m.m. Head very broad, impunctate, clypeus not margined. Thorax almost impunctate, with the hind angles indistinct but a little obtuse. Elytra with fine punctures, which become very indistinct at the sides and extremity. Hind coxce with some moderately coarse punctures, middle of breast quite impunctate. I am not quite sure as to the locality of this peculiar little species, but I believe it is St. Domingo. I have only seen two individuals of it. 75. 245. Bidessus borrei, n. sp. — Brevis, latus, ovalis, valde convexus, posterius acuminatus, nitidus, glaber, castaneo-testaceus, elytris obscurioribus ; prothorace basi utrinque stria subtili, elytris sat crebre subtiliter punctatis ; coxis posterioribus fere impunctatis. Long. 1^ m.m., lat. I m.m. This species seems closely allied to Hydroporus apicatus, but it appears to me to have the prosternal process rather broader, it is also considerably smaller, narrower, and more convex, and the elytra are more obscure in colour. I have seen only a single individual which is in the collection of the Brussels Museum. It is I believe from Pemambuco, and beai-s a label, " fuscipcnuis, Chev." 76. 24G. Il^'phydrus acuminatus, Steinheil, Atti. Soc. Ital. Sci. Nat. XII, p. 249. — Brevis, latus, ovalis, convexus, posterius acuminatus, nitidus, glaber, ferrugineus, elytris obscurioribus, prothorace basi utrinque stria subtili ; elytris sat crebre sub- tiliter punctatis ; coxis posterioribus, sparsim distincte punctatis. Long. H, lat. 1 m.m. Closely allied to Hydroporus apicatus and Bidessus borrei, (Nos. 244 and 245), but has the antennee a good deal thinner than in H. apicatus, and is rather larger and a good deal broader than Bidessus borrei, and has the hind coxse distinctly punctured. I am indebted to .M. Steinheil for an authentic example of this interesting species. Buenos Avres. 77. Group 3. 247. Hydroporus bicarinatus, Clairville, M.C. — Breviter ovalis, subtus convexus, sine pubescentia, nigricans, thorace medio rufescente, elytris testaceis, sutura fasciisque nigris ; supra dense subtiliter sed evidenter, subtus fortiter profundeque On Aquatic Carnivorous Colcoptera or Dytiscida. 347 punctatus ; elytris cristis duabus abbreviatis elevatis ; antennis pedibusque testaceis, plus minusve infuscatis. Long. 2, lat. li m.m. I see no external sexual distinctions in this species. This species varies greatly as to the general colour and markings ; in Corsica very dark specimens are found, the elytra in some of them being nearly entirely black, this is the var. obscurior, Desb. Central and Southern Europe, and North Africa ; lUyria, on the banks of the Isonzo ; Switzerland, France, Spain, Corsica, Algeria and Marocco. 124. 24S. Bidessus bicristatus, n. sp. — Breviter ovalis, latus, subtus convexus, sine pubescentia, testaceus, prothoracis marginibus anterioribus et posterioribus, elytrorum sutura maculisque nigris ; elytris fortiter crebre punctatis, cristis duabus elevatis ; corpore subtus fortiter profundeque punctato. Long. 2, lat If m.m. Closely allied to Hydroporus bicarinatus, but broader and more coarsely punctured, and with the dark marks less : those on the elytra consist of a stripe along the suture which on the middle is dilated so as to form an angular mark, and of a small round mark just at the termination of the inner crista. Found at Jeddah in Western Arabia, by Dr. ]Millingen. 125. 249. Hydroporus porcatus, Klug, M.C. — Oblongo-ovalis, subtus convexus, sine pubescentia, testaceus, prothoracis basi elytrorumque signaturis nigris ; elytris ci-ebre fortiter punctatis, crista unica elevata ; corpore subtus ferrugineo, fortiter punctato. Long. 2i, lat. 13 m.m. In the male the front and middle tarsi are rather longer, and have the basal joint a little more dilated than in the female. Egypt. 126. 250. Hydroporus dohrni, (Wehncke), n. sp. — Breviter ovalis, latus, subtus convexus, sine pubescentia, testaceus, elytris lineis abbreviatis fere parallelis nigris, corpore subtus ferrugineo, fortiter punctato ; elytris fortiter, crebre punctatis, crista longitudinali elevata, alteraque externa obsoleta. Long. 2j-, lat. If m.m. South West Africa. 127. 251. Hydroporus costiponnis, Fairm. Ann, Soc. Fr. 18G.9, p. 1S7. — Breviter ovalis, latus, subtus convexus, sine pubescentia, subtus ferrugineus, supra testaceu^^, sat nitidus, elytris sutura signaturisque transversis nigris; thorace parce puiictato, striga valde obliqua ; elytris fortiter crebre punctatis, cristis duabus elevatis ; corpoir subtus fortiter profundeque punctato. Ste. Marie, Madagascar. 146. TBANS. ROY. DUU. SOC , N S., VOL. II - 2 Z 348 On Aquatic Carnivorous Coleoptera or Dytiscida;. 252. Bidessus insignis, n. sp, — Ovalis, latus, subtus convexus, capite thoraceque rufescentibus, elytris testaceis, basi plagaque magna irregular!, pectore abdomineque nigricantibus, antennis pedibusque testaceis; thorace crebre, basi fortius, punctate ; elytris striis duabus sutiiralibus abbreviatis punctorum impressorum, plica discoidali ultra medium ducta sat elevata, prsetereaque subobsolete punctatis ; coxis posteriori bus punctis magnis. Long. 2 1, lat. \h m.m. This species by its form and sculpture suggests itself as a connecting link between the very dissimilar Dytiscus geminus(No. 269) and Hydroporus bicarinatus,(No. 247). There seems to be scarcaly any difference between the sexes. Western Arabia, (Hedjaz). 1131. 253. Bidessus (Anodochilus) maculatus, Bab. Tr. Ent.Soc. Lond. Ill, 1841, p. 16. — Brevis, sine pubescentia, rufo-testaceus, elytris fuscis, indeterminate testaceo-signatis; prothorace brevi, fere impunctato, basi plicula utrinque fortiter elevata, inter pliculas canalicula profunda transversa ; elytris sat crebre, fortiter, irregulariter subseriatim punctatis, crista tenui elongata; subtus pectore abdomineque basi utrinque grosse punctatis. Long. 2, lat. li m.m. Brazil, (Santa Rita, Aug., 1850, Sablberg). 128. 254. Hydroporus exiguus,Aube, Spec. p. 490. — Brevis, sine pubescentia, rufo-testa- ceus, elytris obscurioribus indeterminate fusco-maculatis ; prothorace brevi, fere im- punctatOjlateribus rugulosis,basi utrinque pliculafortiter elevata, inter pliculas canali- cula profunda transversa ; elytris crebre fortiter punctatis, crista tenui elongata ; subtus pectore abdomineque basi utrinque grosse punctatis. Long. If, lat. 1 m.m. Closely allied to Bidessus maculatus, but rather shorter and broader, and with the elytra a good deal more regularly and evenly, and not so coarsely punctured. United States of North America. 136. Group 4. 255. Hydroporus cinctellus, Lee, M.C. — Obi ongo-ovalis, fere sine pubescentia; sat nitidus, ferrugineus, capite elytrisque infuscatis, his fascia interrupta sub-basali, signaturaque ante-apicali testaceis ; thorace crebre evidenter punctato, elytris et coxis crebre fortiter punctatis; antennis fusco-testaceis. Long. 2, lat. Is m.m. North America. 137. 256. Hydroporus pictodes, n. sp. — Sat latus, ovalis, convexus, subtilissime et omnium brevissime pubescens, vix nitidus, piceo-rufus, thorace testaceo, basi late On Aquatic Carnivorous Colcojjtcra or DytiscidcB. 349 infascato; elytris nigro-fuscis, fascia lata interruptasub-basali,maculaque magna ante- apicali testaceis ; elytris cum thorace dense, distincte, fere oequaliter punctatis ; coxis posterioribus crebre fortiter punctatis ; clypeo anterius marginato. Long. 2, lat. li m.m. North America. 138. 257. Hydroporus plicipennis, Crotch, Tr. Am. Ent. Soc. IV, p. 388. — Oblongo- ovalis, sat latus, fere opacus, brevissime pubescens, fuscus, thorace testaceo, basi et margine anteriore fuscis ; elytris fliscia lata, interrupta, sub-basali, et macula magna ante-apicali testaceis, cum thorace asqualiter dense et distincte punctatis, sutura sat elevata, disco plica longitudinali, lata, elevata ; antennis jjedibusque obscure rufis ; pectore rufo, dense fortiter punctate ; clypeo anterius marginato. Long. 2, lat. It m.m. The only specimen I have seen is a male, and has the front and middle tarsi rather strongly dilated. California. 139. 258. Hydroporus flavicollis, Lee, M.C. — Oblongo-ovalis, opacus, brevissime evi- denter pubescens, testaceus, elytris fuscis, fasciis latis duabus interruptis testaceis ; elytris cum thorace densissime subtiliter punctatis, coxis posterioribus crebre fortiter punctatis. Long. 1#, lat. 1 m.m. The outline of this peculiar little species is much that of Dytiscus duo- decempustulatus, (No. 4G2) ; in the male the front and middle tarsi are distinctly dilated : the hind tibite seem to approximate to those of Deronectes and Hydroporus ; in the only individual I have been able to examine the wings are abortive, so that this will probably prove to be a very distinct and important species. The hind tibiae seem to make a link between Bidessus and Deronectes ; in the specimen I broke up, the wings as stated were undeveloped. North America, (Illinois, Pennsylvania, Massachusetts). 141. 259. Bidessus obesus, n. sp. — Latus, ovalis, convexus, brevissime pubescens, fere opacus, obscure testaceus, elytris obsolete fusco-signatis, thorace et elytris dense subtiliter, fequaliter punctatis ; coxis posterioribus dense fortiter punctatis ; clypeo minus distincte marginato. . Long. 2, lat. 1| m.m. This species is similar in appearance to Hydroporus cribrosus, Schaum, (No. 242), but the upper surface is much more densely, finely, and evenly punctured. The male has the front and middle tarsi distinctly dilated. North America, (Texas). 142. ■ 350 On Aquatic Carnivorous Coleoptera or Dyliscida. 260. Bidessus discretus, n. sp. — Oblongo-ovalis, brevis, sat convexus, fere sine pubescentia rufo-testaceus, elytris fuscis, signaturis magnis pallide testaceis, abdomine plus minusve iiifuscato ; elytris crebrius fortiter punctatis, prothorace minus distincte punctato ; coxis posterioribus fortiter punctatis. Long. 2, lat. li m.ni. The male is shining and has the front and middle tarsi distinctly dilated : of the female there are two forms, one similar to the male in sculpture, the other dull and with the punctuation of the upper surface more obsolete. The plica (or basal im- pression) on the elytra is very distinct, and is about as long as that on the thorax. The colour of the elytra is somewhat variable ; the base is fuscous, but a slight distance from it there is a very broad pale yellow band, which externally reaches as tar forward as the shoulder, and internally is interrupted at the suture, across the middle there is a dark band which indeed extends nearly to the apex, except that there is a very large subapical mark ; the yellow colour, however, at the base and apex is sometimes more extensive owing to the comparative obliteration of the dark marks. North America, (Texas, Belfrage). 1130. 261. Dytiscus unistriatus, Schranck, Bydroporus unistriatiis, M.C. — Ovalis, piceus,vel fuscus,vel rufescens, thorace rufescente, subtiliter sed distincte jiubescens, subnitidus; elytris crebre, distincte, basi sat fortiter punctatis, stria sutunili abbreviata. Lonof. 2, lat. 1 m.m. The male has the front and middle tarsi distinctly dilated. There are two forms of the female, one is quite dull, and has the punctuation quite obsolete ; the other difters but little from the male so far as the sculpture is concerned. This is a very variable species, the colour is sometimes nearly black, with the margins of the elytra, and an interrupted obscure basal fascia pale, the thorax being nearly red : sometimes the general colour is of an obscure red with the suture slightly darker. In Finland is found a variety which is more shining and less pubescent, and has the punctures of the elytra more distinct and distant : I have seen from Lanaeken, in Belgium, two specimens closely approaching this Finland form. Europe, from Lapland to Corsica ; Britain, Belgium, France, Germany. 1 1 G. 262. Hydroporus goudotii. Lap., M.C. — Ovalis, nitidus, tenuissime pubescens, antennis, pedibus, capite thoraceque testaceis, hoc basi infuscato ; elytris fusco- testaceis, signaturis externis indeterminate pallidioribus; crebre punctatis, punctis ad basin versus suturam f ortioribus ; pectore abdomineque piceis. Long. 1 1, lat. 1 ni.m. I do not see any characters by which the male can be distinguished from the On Aquatic Carnivorous Coleoptera or Di/tiscidce. 351 female in this species ; the front and middle tarsi are slender in all the specimens I have examined. This species is very closely allied to Dytiscus unistriatus, but is rather paler in colour than oven the palest varieties of that species ; the male tarsi are undilated ; and the fossa (or transverse depression) behind the middle coxal cavities is much deeper than in that species. Southern Europe : Sicily, Southern France, (Nimes, Beziers, Biaritz and Pyrenees). Algeria, Marooco, 117. 263. Hydroporus pumilus, Aube, M.C. — Ovalis, brevis, latus, sat nitidus, fere nudus, rufo-testaceus, pectore elytrisque infuscatis, his fortiter punctatis maculis tribus externis rufo-tesiaceis. Long. 2, lat. li m.m. In this species I see no sexual difference, the tarsi being slender in all the individuals I have seen. Near Vienna is found a form which may perhaps prove to be a distinct species ; it is considerably narrower in proportion, and has the sculpture of the upper surface less dense : I have not however seen sufficient, individuals to enable me to form a positive opinion. Southern France, and Spain. 118. 264. Hydroporus exornatus, Keiche, M.C. — Ovalis, subtilissime pubescens, tes- taceus, pectore, thoracis basi medio elytrisque infuscatis ; his crebre fortiter punctatis, maculis jalurimis pallidioribus. Long. 2, lat. li m.m. The male has the front and middle tarsi a little dilated ; of the female there are two forms, one quite dull and with the punctuation of the upper surface less distinct, while in the other the sculpture scarcely differs from that of the male. Syria, (Beyrouth), Crete, Turkey. 119. 265. Bidessus coxalis, n. sp. — Ovalis, fusco-niger, thorace testaceo, basi medio infuscato, elytris fasciis interruptis testaceis ornatis, antennis fuscis basi testaceo, pedibus testaceis tarsis obscurioribus ; elytrorum lateribus distincte curvatis ; coxis posterioribus medio sparsim, fere fortiter punctatis ; elytris dense subtiliter punctatis. Long. If, lat. 1 m.m. This species is allied to Hydroporus minutissimus, Germ., (No. 267) but is shorter in form, darker in colour, and has the punctuation of the hind coxae coarser, more distinct and less dense, the sculpture of the upper surface is also less fine and dense. Spain, (Madrid). North Africa, (Tangiers). 120. 352 On Aquatic Carnivorous Colenptcra or Dytiscidce. 266. Hydroporus saucius, Desb. Mitt. Schweiz. ges. Ill, p. 33S. — Ovalis, nigri- cans, thorace in .medio elytrisque maculis parvis externis testaceis, pedibus fuscis, antennariim basi dilutiore ; elytrorum lateribus distincte curvatis ; coxis pos- terioribus medio sparsim fere fortiter punctatis ; elytris dense subtiliter punctatis. Loner, vix 2, lat. 1 m.m. Very closely allied to Bidessus coxalis and probably only a variety of it, but rather larger and darker in colour, .so that the pale marks on the elytra have nearly disappeared. Corsica. 12i. 267. Hydroporus minutissimus. Germ., M.C. — Angustulus, suboblongus, tes- taceus, subtus leviter infuscatus, prothorace basi medio elytrisque fasciis transversis nigris, elytrorum lateribus sat curvatis ; coxis posterioribus medio crebre subtiliter punctatis ; elytris dense subtilissime punctatis. Long. 1§, lat. 1 m.m. I have from Switzerland a pale variety which in some respects is intermediate between this and Hydroporus delicatulus. In Corsica there occurs a dark variety with the black marks of the upper surface much extended. Europe, from South of England to Algeria ; Corsica, and Canary Islands. 122. 268. Hydroporus delicatulus, Schaum, Stet. Zeit., 1844, p. 198. — Elongatus, anp-ustus, depressus, testaceus, elytris fasciis transversis fuscis ; elytrorum lateribus vix curvatis ; coxis posterioribus medio crebre subtiliter punctatis ; elytris omnium dense subtilissime punctatis. Long, if, lat. I m.m. Very closely allied to Hydroporus minutissimus but rather smaller, narrower, and paler in colour, with the punctuation of the coxae and elytra a little finer ; the basal fascia of the elytra indistinct : it is possible that in Switzerland specimens may be found to connect these two forms. Schaum did not distinguish Bidessus coxalis from this and the preceding species, and consequently considered Hydroporus minutissimus as an intermediate form of Bidessus coxalis and Hydroporus delicatulus. Europe, (Germany). 123. Group 5. (A. Each wing-case with a sutural stria). 269. Dytiscus geminus, Fab., Hydroporus geminus, M.C. — Niger, vix nitidus, thorace in medio rufescente, elytris testaceis plaga magna irregulari nigra ; thorace sparsim subtiliter punctate : elytris crebre subtiliter punctatis, et pubescentibus, On Aquatic Carnivorous Coleoptcra or DytiscidcB. 353 antennis basi testaceo apice fusco, pedibus testaceis, tibiis posterioribus apice fusois ; coxis posterioribas sparsim obsolete punctatis. Long. 2h, lat. li. m.m. The sexes differ very little externally, in the male, however, the front and middle tarsi are slightly broader than in the female. The specimens found in Algeria are rather smaller and broader, and have the mark on the elytra rather less in extent, and the punctuation of the elytra more sparing ; but they cannot be considered a distinct species, as intermediate forms occur in Spain. Europe : apparently rare iii Northern Europe, but recorded from Gl" in Finland by Sahlberg. Algeria, Syria. 64. 270. Hydroporus confusus, Klug, Symb.. Phys. IV, t. 34, f 4. — Oblongo-ovalis, subparallelus, testaceus, vertice, prothoracis basi medio, pectoreque infuscatis, abdomine nigricante ; elytris fusco-signatis, signaturis anterius divisis et pro- longatis, sparsim obsolete punctatis ; coxis posterioribus obsolete punctatis. Long. 2, lat. 1 m.m. This species is very closely allied to Dytiscus geminus, (No. 269), but is smaller, narrower, and more parallel, and is more brightly coloured. Though the Hydroporus confusus Klug, was considered by Schaum as not suffi- ciently different from Dytiscus geminus, it appears to me probable that it is really a distinct specie?. Egypt, (Cairo). GG. 271. Hydroporus pentagrammus, Schaum, M.C. — Oblongo-ovalis, testaceus, pro- thorace basi medio, abdominis pectorisque lateribus plus minusve infuscatis ; elytris sutura lineisque duabus posterius conjunctis fuscis, crebre obsoletissime punctulatis, subopacis : coxis fere impunctatis. Long. 2, lat. 1 m.m. Closely allied to Hydroporus confusus, but yet narrower, and more brightly coloured, the elytral markings consist of two dark lines, which are joined together behind, but are throughout quite distinct from the sutural mark. Egypt. 66. 272. Hydroporus thermalis, Germ., M.C. — Oblongo-ovalis, testaceus, pectore abdomineque infuscatis ; elytris sutura lineisque duabus fuscis, interna apice hamata, externa valde abbreviata, sparsim obsolete punctatis ; coxis posterioribus parce obsolete punctatis. Long. 2, lat. 1 m.m. Li this species the thoracic line can scarcely be said to be continued on to the elytra; the continuation is, however, represented by a small fovea or elongate 354 On Aquatic Carnivorous Coleoptera or DytisciJ(s. puncture. The external dark line on the wing case though very short, is generally- very distinct and definite, but sometimes becomes connected with the more elongate internal line. Arabia, Persia, Egyjit, Algeria, Southern Europe. 68. 273. Bidessus major, n. sp. — Oblongo-ovalis, subtus niger, supra nigro testaceoque variegatus, antennis pedibusque testaceis ; prothorace sparsim distincte punctato, medio testaceo, basi margineque apicali fuscis ; elytris versus suturam distincte sat crebre punctatis ; coxis posterioribus parce subtiliter punctatis. Long. 3, lat. If m.m. This species is very similar to Dytiscus geminus, (No. 269), but is more than twice as large, and the punctuation of the upper surface is rather coarser. Arabia ; Persia. 69. 274. Hyphydrus hamulatus, Gyll., Hydroporus hamulatus, M.C. — Oblongo- ovalis, opacus, testaceus, abdomine infuscato, elytris lineis duabus crassiusculis fuscis, interna apice hamata, externa abbreviate ; elytris densissime fequaliter subtiliter punctatis : coxis posterioribus obsolete punctatis. Long. 2, lat. 1 m.m. The pubescence of the upper surface is very fine but distinct ; the thorax is rather closely, finely and evenly punctured, but not so densely and finely as the elytra. This species is excessively rare ; I am indebted to Dr. J. Sahlberg of Helsingfors for the only individual I have seen. Its structure appears very similar to that of Dytiscus geminus and its allies ; mj' specimen is probably a male, for the four front tarsi are rather broad. Scandinavia, among marine Confervre. 71. 275. Bidessus lajticulus, n. sp. — Oblongo-ovalis, nitidus, fere ItBvis, rufo-testaceus, subtus lateribus infuscatis ; elytris signaturis fuscis, punctis impressis distantibus, subtilibus sed distinctis ; coxis posterioribus paicissime subtiliter punctatis. Long. 2, lat. 1 m.m. The thorax is almost impunctate. The markings on the elytra are a dark transverse angulated one at thejextreme base, a dark common line on the suture, a longitudinal line outside the sutural one and Avhich is at its hind part thickened externally, a smaller dark mark near the outer margin, and a mark near the humeral angle connecting the basal mark with the others. The species much re- sembles Hydroporus japonicus, (No. iJSG), but is readily distinguished by the abbreviated impressions of the elytra and thorax. I see no sexual diflferences. Siam, (Bangkok) : Celebes, (Macassar, Jan. 1874, Beccari). 72. On Aquatic Carnivorous Coleoptera or Dytiscidce. 355 276. Hydroporus strigicollis, (Fairm.), n. sp. — Sat angustus, minus convexus, opacus, subtiliter pubescens, fuscus, thorace in medio pallidiore ; elytris subtiliter fere dense punctatis, coxis posterioribus sparsim sub-obsolete punctatis. Long. 2, lat. ll m.m. I have seen only two individuals (in bad condition) of this species, and do not know their sex. It is readily distinguished from Dytiscus geminus, (No. 269), by the narrower form and darker colour ; and by the basal striga of the elytra, which is excessively short. Madagascar. 145. 277. Bidessus sordidus, n. sp. — Oblongo-ovalis, subopacus, pectore abdomineque nigris, prothorace testaceo, basi margineque apicali nigris ; elytris testaceis minus discrete fusco-signatis, sat crebre sub-obsolete punctatis ; antennis pedibusque testaceis, illis apicem versus plus minusve infuscatis ; coxis posterioribus obsolete punctatis. Long. 21, lat. 1^ m.m. Very closely allied to D. geminus, (No. 269), but larger, and longer in proportion to the width. The markings on the elytra are indistinct and confused, and consist of some longitudinal marks more or less confluent, much as in Hydroporus confusus, (No. 270). In the male the front and middle tarsi are a good deal broader than in the female. Abyssinia. 73. 278. Hydroporus lineolatus. Boh., M.C. — Oblongo-ovalis, nitidus, testaceus, pectore abdomineque nigris ; elytris disco irregulariter minus discrete fusco, sparsim subtiliter punctatis tenuissimeque pubescentibus ; coxis posterioribus fere impunc- tatis. Long. 2\, lat. I3 m.m. I have seen only two individuals (in very bad condition) of this species, which appears to me to be very closely allied to Dytiscus geminus, (No. 269). It is however rather larger, and narrower in form, more shining and more sparingly punctured, and has the dark marks on the elytra very indistinct. The thorax is nearly entirely reddish, and there is no distinct dark mark at the base of the elytra. I am not at all sure whether this is really the species described by Boheman under this name ; he describes an insect having four distinct lines on each wing case ; the two individuals I have described scarcely agree on this point, in one of them scarcely any trace of dark lines is to be seen, while the other might be described as having two or three indistinct dark lines on each wing case. South Africa, (Cafii-aria ; Cape Good Hope). 74. TBANS. BOY. DDB. SOC, N.3., VOL. II. J A 356 On Aquatic Carnivorous Coleojjtera or Dyliscidae. 279. Bidessus striola, n. ,sp. — Oblongo-ovalis, subopacus, testaceus, sutura elytrorum, pectorp. abdomineque infuscatis ; crebre obsolete punctatus, subtus fere iinpunctatus. Long. 23, lat. Ij m.m. Var. Elytris fascia basali maculaque magna communi nigricatitibus. The head is impunctate, and the thorax has only a few very indistinct punctures ; the punctures on the elytra are close, but very indistinct ; the striola at the base of the elytra is fine and very short, being rather shorter than that of the thorax, the thoracic striola itself is short, reaching not quite half way to the front. The coxse are almost impunctate. In the male the front and middle tarsi are a little broader than in the female. Celebes, (Wallace). The variety with a pattern on the elytra found at Macassar, January 1874, by Beccari. 79. 280. Hydroporus basalis, MacLeay, Tr. N. S. W. 1871, p. 124. — Oblongo-ovalis, brevis, nitidus, capite, thorace, antennis pedibusque testaceis, thoracis basi medio fusco, elytris longitudinaliter fusco-signatis, crebre obsoletissime punctatis ; abdomine pectoreque fuscis. Long, if, lat 1 m.m. This species is rather similar to Hydroporus confusus, (No. 270), but is a good deal smaller. I have no doubt that I have the sexes before me, but they show very slight distinctions. Australia, (Gayndah, Rockhampton). 91. 281. Bidessus signatus, n. sp. — Oblongo-ovalis, rufo-testaceus, nitidus, elytris sparsim subtiliter punctatis, thoracis basi medio, pectore abdomineque nigricantibus, elytris sutura lineisque duabus longitudinalibus (interna extus hamata, externa abbreviata) nigris. Long. 21^, lat. li m.m. This species is very closely allied to Hydroporus thermalis, (No. 272), but is rather larger, and has the elytra more sparingly punctured. I have seen but two specimens which are I think males, though they have the four front tarsi slender. Australia, (Brisbane). 92. 282. Bidessus godeffroyi, (Wehncke), n. sp. — Oblongo-ovalis, subopacus, testaceus, thoracis basi medio elytrisque fuscis, his basi lateribus apiceque testaceo-maculatis, -dense obsoleteque punctatis, subtiliter distincteque pubescentibus. Long. 2, lat. \\ m.m. Though I have examined several specimens, I see no sexual distinctions. Australia, (Gayndah, Rockhampton, Melbourne). 93. On Aquatic Carnivorous Coleoptera or Dyliscidce. 357 283. Bidessus daemeli, (Wehncke), n. sp. — Oblongo-ovalis, sat elongatus, sub- opacus, rufo-testaceus, prothorace basi medio nigro, elytris fusco-variegatis, dense subtiliter punctatis, distincteque pubescentibus ; coxis posterioribus subtiliter ^ed perspicue punctatis. Long. 2|, lat. It m.m. Mas, tarsis anterioribus et intermediis mediocriter dilatatis, abdomine infuscato. Fern., tarsis simplicibus, abdomine riifo. Australia, (Cape York, Port Denison, Rockhampton). 94. 284. Hydroporus mastersi, MacLeay, Tr. N. S. W. 1871, p. 123.— Oblongo- ovalis, elongatus, subopacus, rufo-testaceus, thorace basi medio elytrisque nigro- signatis, pectore abdoiuineque fuscis ; elytris dense subtiliter punctatis, coxis posterioribus crebre fortiter punctatis. Long. 3, lat. IJ m.m. In the male the front tarsi are distinctly broader than in the female, and the hind tarsi are slightly longer. Australia, (Gayndah, Rockhampton). 95. 285. Bidessus orthogramraus, n. sp. — Oblongo-ovalis, elongatus, subopacus, rufo- testaceus, thorace basi medio elytrisque nigro-signatis ; elytris dense subtiliter punctatis, coxis posterioribus crebre sat fortiter punctatis. Long. 2f, lat. ll m.m. I have seen only a single female individual, and it is just possible it may not be distinct from Hydroporus mastersi ; it is brighter in colour, and unicolorous beneath, the markings on the elytra are less confused and more linear longitudinally, the punctuation of the upper surface is a little more dense, and that of the hind coxae not quite so coarse. North-west Australia. 96. 286. Hydroporus japonicus. Sharp, Tr. Ent. Soc. Lond. 1873, p. 54. — Oblongo- ovalis, supra rufo-testaceus, capite prothoracisque basi plus minusve infuscatis, elytris sat crebre distincte punctulatis, signaturis longitudinalibus plus minusve coalescentibus nigris ; subtus piceus, coxis posterioribus parce et subtiliter sed distincte punctatis. Long. 2, lat. 1 m.m. Rather narrower and more parallel than Dytiscus geminus, (No. 269), more brightly coloured, and with the punctuation of the upper surface more distinct, and the sides of the thorax a little curved. The external sexual characters seem to consist only in a very slight dilatation of the front and middle tarsi in the male. ■ This species varies a good deal in size and colour, and in the markings of the 3 A3 358 On Aquatic Carnivorous Coleoptera or DytiscidtB. elytra. The Chinese specimens are smaller and paler and less variegated in their marks than those I have seen from Japan, but I have no doubt all are one species. Japan, China, (Kiu Kiang, Mr. Geo. Lewis). 65. 287 Hydroporus orientalis, Clk., M.C. — Oblongo-ovalis, subopacus, rufo- testaceus, elytris fuscis, testaceo-signatis, crebre, subtiliter, sub-obsolete punctatis distincteque pubescentibus. Long. \i, lat. 1 m.m. The elytra have a pale lateral border, which behind the base is greatly dilated and extends inwardly nearly to the suture, it is also broader and more projecting inwards at the apex, and again at an intermediate spot. The male differs from the female by having the front and middle tarsi moderately dilated. The species is extremely similar to a variety of Bidessus striola, (No. 279), which has the elytra similarly marked, but that species has the under surface more obscurely coloured. Siain, (Bangkok, Castlenau). 104. 288. Bidessus transversus, n. sp. — Oblongo-ovalis, rufo-testaceus, nitidus, elytris fuscis, testaceo signatis, sat crebre, minus subtiliter punctatis, sparsim subtiliter pubescentibus, stria suturali basin versus obsoleta ; coxis postei'ioribus medio sparsim distincte punctatis. Long. 1|, lat. 1 m.m. The pale marks on the elytra consist of a narrow lateral margin, with a broad patch extending inwardly behind the base, and a much narrower process behind the middle, the terminal portion of which is abruptly turned forwards. The only individual I have seen is I think a male, if so the front and middle tarsi are only slightly dilated. Siam, (Bangkok). 105. 289. Hydroporus intermixtus. Walk. (?), M.C. — Oblongo-ovalis, sub-brevis, sat nitidus, tenuissime pubescens, capite, thorace, antennis pedibusque testaceis, elytris sordide testaceis, sutura infuscata ; pectore fusco-testaceo, abdomine nigricante ; elytris minus dense obsolete punctatis; corpore subtus fere impunctato. Long. Ij, lat. 1 m.m. This species is closely allied to Bidessus striola (No. 279), but is much shorter and has the elytra more sparingly punctured. I have seen three individuals. Sumatra, (sent by Wehncke). 455. On Aquatic Carnivorous Coleoptera or Dytiscidce. 359 290. Bidessus fuscipennis, n. sp. — Oblongo-ovalis, angustulus, rufo-testaceu^, sat nitidus, elytris abdominisque lateribus infuscatis ; elytris fortiter sat crebre punctatis, stria suturali profunda ; coxis posterioribus medio sparsim, obsolete punctatis. Long. 2, lat. I m.m. The pubescence on the elytra of this species, though scanty is rather long, and distinct ; the elytra have no defined mai'ks, but the sides just behind the shoulders are rather paler, and behind this rather darker than elsewhere. I do not know the sex of the only individual I have seen. Siam. lU. 291. Bidessus denticulatus, n. sp. — Oblongo-ovalis, elongatus, sub-opacus, rufo- testaceus, elytris nigro-signatis, cum thorace dense (Bqualiter sat subtiliter punctatis ; coxis posterioribus subtiliter sed perspicue punctatis. Long. 3, lat. IJ m.m, I have seen but two individuals of this very distinct species, and I have no doubt they are male and female^ though the characters that distinguish them are very slight, the male tarsi being only slightly broader than those of the female. The prosternal process is broad, the stria on the thorax is minute, and the elytra are denticulate near the extremity. Australia, (Rockhampton). 97. 292. Bidessus flammulatus, n. sp. — Oblongo-ovalis, angustulus, capite, thorace, antennis pedibusque testaceis, thorace basi medio infuscato, pectore, abdomine elytrisque fuscis, his pone basin, lateribus apiceque testaceo-signatis, crebre, subtiliter, sub-obsolete punctatis, distincte pubescentibus. Long. 2i, lat. \\ m.m. The pale markings of the elytra consist of a waved and angulated fascia behind the base, which extends somewhat backwards along the sides, of an apical mark, and of a lateral mark between these. The punctures of the coxae are sparing, and extremely obsolete. The male has the front and middle tarsi rather strongly dilated ; the female I have not seen. China, (Kin Kiang, Mr. Geo. Lewis). ] 03. (B. no sutural stria on wing cases). 293. Hydroporus amabilis, Clk., M.C. — Oblongo-ovalis, lasvigatus, pernitidus, fuscus, pedibus testaceis, cajiite thoraceque ssepe rufo-testaceis ; elytris fusco- testaceis, versus suturam distincte punctatis, humeris et lateribus Itevigatis ; thorace basin versus fere paulo latiore. Long. 3i, lat. \\ m.m. 360 On Aquatic Carnivorous Coleoptera or Dytiscidai. This species varies in colour, form and punctuation, and also in size, and even a little in the thickness of the antennae. The male has the front and middle tarsi rather broader than in the female. Australia, Tasmania ; apparently common, (Melbourne, Port Denison). 80. 294. Bidessus inornatus, n. sp. — Oblongo-ovalis, angustulus, Isevigatus, pernitldus, rufo-testaceus, elytris obscurioribus, subtus lateribus infuscatis ; elytris apice et versus suturam crebre subtiliter punctatis ; thorace basi quam medio fere angus- tiore; antennis tenuibus Long. 2|. lat. 1| m.m. Closely allied to H. amabilis, readily distinguished by its more parallel and narrower form, and the more parallel-sided thorax. I have seen only one individual, which is a male, and has the front and middle tarsi (especially these latter) very much broader than they are in H. amabilis. West Australia, (Duboulay). 81. 29.5. Bidessus impressus, n. sp. — Oblongo-ovalis, laBvigatus, pernitidus, testaceus, subtus nigricans, elytris fusco-testaceis ; his crebre distincte punctatis, punctis versus latera apicemque obsoletioi'ibus ; prothoracis lateribus fere parallehs ; antennis (preesertim in femina) crassiusculis. Long. 3, lat. vix li m.m. Closely allied to Hydroporus amabilis, but with the thorax narrower behind, the punctures of the elytra more distinct, and the prosternal process narrower and less parallel. The male has the front and middle tarsi moderately dilated, and the antennae longer and more slender than in the female. The specimens in my collection labelled Australia bear no special locality and may perhaps be actually from New Zealand. New Zealand, and Australia. 82. 296. Bidessus plicatus, n. sp. — Oblongo-ovalis, laevigatus, nitidus, castaneo- testaceus ; elytris sat crebre et fortiter punctatis, punctis lateribus et apice sub- tilioribus ; prothoracis lateribus subparallelis. Long. $ 2i, p 21, lat. li m.m. Closely allied to Bidessus impressus, but smaller, and more pallid, and with the antennae of the female considerably more slender. The male has the front and middle tarsi a good deal more dilated, and the elytra are more elongate ; the breast and abdomen are black. In the female the elytra are short, and not so parallel-sided, the colour of the breast and ventral segments is more or less infuscate testaceous, and the antennae are rather shorter than they are in the male but not stouter. The specimens gent by Mr. Lawson, from Auckland, are females, and are slightly On Aquatic Carnivorom Coleoptera or Dytiscidce. 361 larger and more distinctly punctured than those sent by Capt. Broun : the specimens from the Southern Island also depart considerably from the type in some of the details, and possibly there may prove to be more than one species. New Zealand, (North Island, Capt. T. Broun and R. Lawson ; Cliristchurch, Wakefield ; Otago, Prof. Hutton). 83. 297. Bidessus huttoni, n. sp. — Oblongo-ovalis, supra testaceus, subtus nigricans; -elytris versus suturam vix fortiter punctatis ; prothoracis lateribus subparallelis. Long. 3, lat. I3 m.m. The male is moderately shining on the wingcases, and has the front and middle tarsi but little dilated. The female has the upper surface dull, and the elytra rather shorter and broader than in the male, and its antennae are stouter. Although very similar to B. plicatus, the two species are easily distinguished when the corresponding sexes are compared ; the male of B. huttoni has the anterior and j^articularly the middle tarsi almost without dilatation, and can thus be distinguished from the corresponding sex of B. plicatus ; while the female of B. huttoni, is readily recognised by its dull upper surface and incrassate antennae. New Zealand, (Otago, a pair sent by Prof. Hutton in 1877). 1127. 298. Hydroporus shuckhardi, Clk., M.C — Oblongo-ovalis, capite thoraceque rufo- testaceis, sparsim obsoleteque punctatis ; el3ftris fusco sub-nebulosis, crebre punctatis. Long. 2i, lat. Ij m.m. Mas, major sat nitidus, autennis mediocribus, tarsis anterioribus et intermediis fortiter dilatatis, pectore abdomineque nigricantibus. Fern., minor, opaca, antennis crassis, tarsis simplicibus, pectore abdomineque rufescentibus. This species is allied to Hydroporus bistrigatus, but is smaller, and the sexual disparity is greater. Aiistralia, (from Melbourne to Queensland, but apparently rare). 85. 299. Hydroporus bistrigatus, Clk., M.C. — Oblongo-ovalis, elytris dense sub- tilissime punctatis, pone medium fusco-nebulosis ; pectore nigerrimo ; coxis posterioribus sparsim distincte punctatis. Long. 3, lat. \\ m.m. Mas, sat nitidus, tarsis anterioribus et intermediis fortiter dilatatis, abdomine nigro. Fern., fere opaca, antennis paulo crassioribus et brevioribus, tarsis simplicibus, abdomine lagte rufo-testaceo . Australia, (apparently common and widely distributed). 84. 36iJ On Aquatic Carnivorous Coleoptera or Dytiscidce. 300. Hydroporus compactus, Clk., M.C. — Ovalis, Isevigatus, pernitidus, rufo- testaceus, elytris paulo obscurioribus, his versus suturam crebre sat fortiter puiic- tatis, humeris et lateiibus impunctatis. Long. 2,, lat. li m.m. This species is readily distinguished by its peculiar form, giving it somewhat the aspect of one of the Noterini ; the elytra continue the outline of the thorax almost without any interruption, and their hinder part is attenuate and narrow. The prosternal process is broader than it is in the allies. In the male the antennee are more slender than in the female, and the front and middle tarsi are slightly broader. This species varies in form; some specimens (especially those from Brisbane) being more elongate than others. Eastern Australia, (from Melbourne to Brisbane). 86. 301. Hydroporus gemellus, Clk., M.C. — Oblougo-ovalis, angustulus, subopacus, rufescens, elytris vix obscurioribus, abdomine pectoreque nigricantibus ; elytris versus suturam crebi-e punctatis ; tibiis anterioribus tarsisque posterioribus gracilibus. Long. 3, lat. l\ m.m. This species is distinguished amongst its immediate allies, by its narrower form, and its slender front tibiae, and slender and elongate tarsi. I have only seen two individuals of this species, which I believe are both females ; both have lost the anteunpe except that in one the six basal joints remain, these are rather slender. Australia, (proljubly the western portion ; South Australia, fide Clark.) 87. 302. Bidessus muudus, n. sp. — Oblongo-ovalis, sat angustulus, subopacus, rufescens, elytris vix obscurioribus, pectore nigricante, abdomine piceo ; elytris crebre punctatis ; tibiis anterioi'ibus crassiusculis, tarsis posterioribus sat gracilibus. Long. 3, lat. I5 m.m. Intermediate between Hydroporus gemellus and Bidessus biformis, distinguished from the latter by its rather smaller size and narrower form, by the less obsolete punctuation at the base of the elytra, and rather more slender legs. I believe I have the sexes of this species before me, and if so they are very similar, the tarsi indeed show no difference, but the antennae of the male are slightly more elongate ; in both sexes they are rather slender. Australia, (probably the west). 88. 303. Bidessus biformis, n. sp. — 6 Oblongo-ovalis, nitidulus, fusculus, capite thoraceque rufescentibus ; elytris basi sparsim apice crebre punctatis ; antennia On Aquatic Carnivorous Coleoptera or Dytiscicfce. 363 gracilibus, tibiis anterioribus sat latis ; tarsis anterioribus et intermediis fortiter dilatatis tarsis posterioribus gracilibus. Long. 3, lat. vix I2 m.m. P Oblongo-ovalis, sericeo-subopaca, rufescens, elytris pectoreque obscurioribus ; elytris basi sparsim apice crebre punctatis ; antennis brevioribus, crassiusculis, tibiis anterioribus latis, tarsis posterioribus crassiusculis. Long. 2$ m.m. The sexes of this species have the appearance of being quite distinct species. Australia, (King George's Sound, Swan River.) 89. 304. Bidessus dispar, n. sp. — Oblongo-ovalis, brevis, obscure castaneus, elytris crebre punctatis, tibiis anterioribus et tarsis posterioribus sat gracilibus. Long. 2i, lat. 1 m.m. Mas, nitidulus, elytris sat fortiter punctatis, antennis gracilibus, tarsis anterioribus et intermediis leviter dilatatis. Fern., (a.) subopaca elytris subtiliter punctatis, antennis crassis. (b.) opaca elytris obsolete punctatis, antennis crassis. In this species there exists two forms of the female and the sexual characters are very remarkable ; besides those mentioned above, the hind legs of the male are a little lonsrer and more slender than those of the female. Australia, (Swan River). 90. 305. Bidessus occultus, n. sp. — Sub-oblongus, parum elongatus, castaneo- testaceus, capite obscuriore ; elytris crebre subtiliter punctatis ; coxis posterioribus paxce subtiliter punctatis. Long. 1|, lat. 1 m.m. This little species differs from Hydroporus lacustris (No. 319), by its smaller size more strongly punctured el}i;ra and paler under surface. It is still closer to some of the smallest varieties of Hydroporus affinis (^No. 318), but it is still smaller, and is of different form, its upper surface being flatter, and the outline much less acuminate behind and the wing-cases are without paler markings. I have seen only a single individual. Arabia, (El Hedjaz. Dr. C. jSIillingen). 1128. 306. Bidessus perforatus, n. sp.^-Clypeo antice incrassato, sed vix marginato ; oblongo-ovalis, brevis, rufo-testaceus, elytris sordide testaceis obsoleteque parce fusco-adspersis, fortiter sat crebre punctatis, fere nudis : coxis posterioribus abdom- inisque segmentis basalibus utrinque fortiter punctatis. Long, vix 2, lat. 1 m.m. The only two specimens I have seen of this distinct little species, have the front and middle tarsi very slender, and are probably females. The prosternal process is strongly margined at the sides. China, (Kiu Kiang, Mr. Geo. Lewis). 106. TRASS. BOY. DITB. SOC. S.S., VOL. n. 364 On Aquatic Carnivorous Coleoptera or DytiscidcB. 307. Bidessus dilutus, n. sp. — CljiJeo antice submarginato ; oblon;^o-ovalis, brevis, minus latus, rufo-testaceus, elytris sordide testaceis obsoleteque parce fusco- puactatis ; coxis posterioribus abdominisque segmentis basalibus utrinque fortiter sat profunde punctatis. Long. If, lat. 1 m.m. Closely allied to Bidessus perforatus but a good deal smaller and rather narrower, and with the punctuation of the under surface less developed. Siam, (Bangkok). 107. 308. Hydroporus pulicarius, Aube, Spec. p. 494. — Oblongo-ovalis, subtiliter pubescens, supra opacus, testaceus, elytris obscurioribus obsolete punctatis ; coxis posterioribus medio sparsim sat fortiter sed minus profunde punctatis. Long, if, lat. 1 m.m. This species is variable, and it is possible I have mixed more than one under the name ; but 1 do not see any characters sufficient to distinguish the two Brazilian from the two North American individuals I have seen. America, North and South, (Florida ; Santa Rita, Brazil). 143. 309. Hydroporus caraibus,Chev.,M.C. — Oblongo-ovalis, subtiliter pubescens, supra opacus, testaceus, elytris obscurioribus, externe indistincte fuscomaculatis, obsolete punctatis; coxis posterioribus medio sparsim obsolete jjunctatis. Long. 2, lat. 1 m.m. Closely allied to Hydroporus pulicarius, but rather larger and more elongate, and with the coxae more obsoletely punctured. Cuba. 144. 310. Hydroporus chilensis, Sol., M.C. — Oblongo-ovalis, sat latus, subtus niger, aiitennis pedibusque testaceis, capite thoraceque fusco-testaceis, hoc lateribus dilutioribus, elytris testaceis, fusco signatis, dense sat fortiter punctatis; coxis posterioribus fortiter punctatis. Long. 2, lat. li m.m. The male is more shining than the female, and has the punctuation of the upper surface deeper and more distinct, and the front and middle tarsi are slightly broader. Chili. 101. 311. Hydroporus flavofasciatus, Steinheil, Atti. Soc. Ital. Sci. Nat. XII, p. 249. — Oblongo-ovalis, minus latus, sine pubescentia, sat nitidus, .subtus niger, antennis pedibusque sordide testaceis, supra fusco-niger, prothoracis lateribus obscure dilutioribus, elytris fascia lata sub-basali plus minusve interrupta testacea ; thorace elytrisque dense profunde punctatis ; coxis posterioribus fortiter punctatis. Long. If, lat. 1 m.m. On Aquatic Carnivorous Coleoptera or Dytiscidce. 365 This species is very similar to Hydroporus cliilensis, but is a good deal smaller and narrower. I have seen only a single individual, for which I am indebted to Herr Steinheil. South America, (Achiras). 454. 312. Bidessus uruguensis, n. sp. — Oblongo-ovalis, nitidus {$), vel opacus (p), obsoletissime punctatus, parcissime brevissime pubescens (fere nudus), fuscus, capite, thorace, antennis pedibusque testaceis, thorace medio infuscato, elytris obsolete et minus late testaceo-signatis ; coxis posterioribus impunctatis. Long, vix 2, lat, 1 m.m. The fuscous colour by which the elytra are suffused, leave some ill-defined small pale marks. The male is shining and has the fine and scanty punctuation of the elytra distinctly visible, while the female is dull and without distinct sculpture : the tarsi of the male are rather broader and shorter than in the female. The species is scarcely distinct from some of the varieties of Hydroporus affinis (No. 318), but the male is more obsoletely punctured, and the female has the upper surface dull, without sculpture. South America ; Uruguay. 109. 313. Bidessus nitidus, (Bab). — Oblongo-ovalis, nitidus, nudus, fuscus, capite, thorace, antennis pedibusque testaceis, elytris indeterminate testaceo-signatis, interne crebre fortiter punctatis, lateribus fere impunctatis ; coxis posterioribus medio parce sub-obsolete punctatis. Long. 2, lat. 1 m.m. The male has the front and middle tarsi slightly dilated. This is extremely closely allied to some of the varieties of Hydroporus affinis (No. 318), but it is a little broader than any of them, and the punctuation of the elytra is coarser and more sparing ; and the few punctures on the coxse are less obso- lete ; it is still more similar to Hydroporus liliputanus (No. 316), but the impression on the elytra is more elongate and the punctures on the coxse fewer and smaller. This species was described by Babington under the name of Hydroporus nitidus, but this name cannot be used on account of the prior Hydroporus nitidus, Sturm. Brazil. (Petropolis, May and December, 1850 ; Santa Rita, August, 185U, R. F. Sahlberg.) 110. 314. Bidessus crassus, n. sp. — Brevis, latus, nitidus, nudus, testaceus, pectore abdomineque infuscatis ; elytris indeterminate fusco-punctatis et lineatis, circa suturam basin versus fortiter minus crebre punctatis, lateribus apiceque Isevigatis ; coxis posterioribus omnino Isevigatis. Long. If, lat. 1 m.m. This species is distinguished among its immediate allies by its very short, broad 3 B 2 '666 On Aquatic Carnivorous Coleoptera or Dytiscidce. form ; the dark markings on the elytra consist of one or two lines and several spots, or thickened and interrupted lines : the hasal ventral segment of the hind body shows a single series of punctures on each side and elsewhere is quite smooth. The only specimen I have seen is, I think, a female. Brazil, (Santa Rila, August, 1850, E. F. Sahlberg). 111. 315. Bidessus atomarius, n. sp. — Ovalis, angustulus, Isevis, nitidus, impunctatus, rufo-testaceus, elytris infuscatis, pone basin et ad apieem testaceo-signatis. Long, la, lat. Im.m. This minute species looks like a Laccophilus. 1 have seen only three individuals, all of which have the front and middle tarsi quite slender. Brazil, (Petropolia, May, 1850, R. F. Sahlberg). 112. 316. Hydroporus liliputanus, Aube. M.C. — Oblongo-ovalis, sat latus, nitidus, fuscus, antennis pedibusque testaceis ; elytris versus suturam crebre sub-obsolete punctatis, stria discoidali impressa ; coxis posterioribus omnino Isevigatis. Long. 2, lat. 1 m.m. Aube's unique type i.s a little paler than the specimen above described, but otherwise I see not the least difference. BrazU, (Bahia). 113. 3 1 7. Bidessus texanus, n. sp. — Oblongo-ovalis, angustulus, sub-depressus, dense subtilissime pubescens, sub-nitidus, testaceus, abdomine pectoreque nigricantibus, ■elytris sutura fasciisque transversis fuscis, dense subtilius punctatis ; corpore subtus fere irapunctato. Long. \l, lat. 1 m.m. This species is very similar in appearance to the European Hydroporus minutis- simus, (No. 267) ; I have seen only two individuals, both of which have the front and middle tarsi quite slender. North America, (Texas, scut by Belfrage). 456. 318. Hydroporus affinis Say, M.C. — Oblongo-ovalis, sat angustus, sat nitidus, fere nudus, fuscotestaceus, pedibus, capite thoraceque testaceis, hoc disco infuscato ; elytris plus minusve distincte pallido-signatis, mediocriter punctatis ; coxis posterioribus medio parce obsolete punctatis, vel Icevigatis. Long. l|, lat. 1 m.m. Obs. species statura, pictura, punctatura coloreque corporis variabilis. This species is very variable, and I had at first separated the variations as dis- tinct species, but after a repeated study I have been unable to detect any definite characters to distinguish the varieties. On Aquatic Carnivorous Coleoptera or DytiscidcB. 367 BVom Sitka I have seen a small variety, (Hydroporus erythrostomus, Mann.), in which the elytra are largely pale with a few fuscous vittse, this form is narrow and the punctuation fine, and the colour beneath is dark. In California there is a variety, (H. obscurellus, Lee.) which is very dull, and of an obscure fuscous red colour, almost without markings on the elytra, and the colour of the under surface dark. In Nevada occurs a variety in which the elytra are much variegate, and the colour beneath is between black and yellow. In Utah the specimens I have seen are large, with much variegate elytra, and black beneath. H. macularis, Lee. is entirely pale beneath, it is of small size, and I can see nothing to distinguish it from the Sitka specimens except the rather paler colour of the under surface. In Central America the colour is dark, and the punctuation of the elytra scanty. The specimens from Chili are variable in colour and punctuation, but I cannot find any constant distinction from the North American specimens : and the same remark applies to H. bonariensis, Steinheil. H. strobeli, Steinl. from S. Luis, differs but little from the North American type. North and South America, from Sitka to Buenos Ayres. 102, 115, 129, 130, 132, 135. 319. Hydroporus lacustris, Say, M.C — Oblongo-ovalis, nitidulus, parce subtiliter pubescens, testaceus, abdomine pectoreque nigris ; elytris ochraceis, sat crebre sub- tiliter punctatis ; coxis posterioribus nitidis, impunctatis. Long. 1|, lat. 1 m.m. The punctuation of the upper surface in this species is finer than in any of the North American immediate allies. The colour of the under surface varies, some- times the ventral segments are black, sometimes yellow. The tarsi are slender in all the specimens I have examined, (eight in number), and I see no sexual characters. The species is easily distinguished from Hydroporus affinis, and H. fuscatus, by the stria at the base of the elytra being rather longer than the thoracic stria ; it has also traces of a sutural stria on the elytra. North America, (Massachusetts, Texas). 133. 320. Hydroporus fuscatus. Crotch, Tr. Am. Ent. Soc. IV, p. 391. — Oblongo- ovalis, minus angustus, nitidulus fere sine pubescentia, rufescens, elytris fusco- signatis, sat crebre fortiter punctatis, striga basali brevissima vel omnino nulla ; coxis posterioribus medio sparsim fortiter punctatis. Long. 2, lat. 1 m.m. This species is readily distinguished from all the varieties of Hydroporus affinis, (No. 318), by the comparatively coarse punctuation of the hind coxse, and the very 368 On Aquatic Carnivorous Cokoptera or Dyiiscidce. short impressed stria at the base of the elytra. It varies a little in colour and size, some individuals haviug the hind body and breast infuscate. The length of the striga also varies a little, it is sometimes so abbreviated as to be scarcely perceptible. Atlantic States of North America: "from Lake Superior to Florida," Crotch. 131. 321. Hydroporus pullus, Lee, M.C. — Elongato-ovaUs, nitidulus, tenuissime pubescens, testaceus, elytris vittis elongatis fuscis tribus, crebre distincte punctatis ; coxis posterioribus pectoreque impunctatis, nitidis. Long. 2, lat. 1 m.m. In this species the apical ventral segment is a good deal broader and larger than in its allies, and by this character it may readily be distinguished from varieties of other North American species which resemble it in appearance : it has moreover an indistinct dorsal stria extending about half the length of the wing-case. The tarsi are rather long and slender, but I see no differences between the sexes. North America, (Red River, Pennsylvania, Louisiana). 134. 322. Hydroporus granarius, Aube, M.C. — Breviter ovalis, latus, subtus convexus,. subtiliter pubescens, nitidus, ferrugineus, elytris obscurioribus ; prothorace obsolete punctato, elytris crebre distincte punctatis ; coxis posterioribus nitidis, sparsim, subtiliter sed distincte punctatis ; abdomine fere impunctato ; antennis fuscis, basi testaceo. Long, if, lat. ll m.m. This species has the form of a minute Hyphydrus, the elytra continuing the outline with the thorax. I see no sexual characters among the five specimens I have examined, all of which have the tarsi small and rather slender. United States of North America, (Massachusetts). 140. 323. Bidessus lynceus, n. sp. — Brevis, ovalis, fere sine pubescentia, nigricans, capite fusco, prothorace ad angulos anteriores late testaceo, elytris fasciis duabus, transversis, flaminulatis, testaceis ; prothorace basi et disco punctatis ; elytris^ crebrius sat fortiter, pectore fortiter, punctatis ; antennis testaceis, apicem versus plus minusve infuscatis. Long. 2, lat. ll m.m. The male has the upper surface a little shining, the anterior and middle tarsi are but little dilated : in the female the upper surface is dull. The species is allied to Hydroporus cinctellus, Lee. (No. 255) but it is a good deal broader and shorter, and the fasciae on the elytra are very irregular, being irregularly angulate ; these yellow marks are variable in their extent, sometimes occupying nearly half the surface of the wing-cases, and at other times diminished in size, and broken into more or less separated marks. Central America, (Guatemala City, E. C. Champion). 1129. On Aquatic Carnivorovs Coleoptera or Dytiscidce. 369 324. Bidessus discoidalis, n. sp. — Oblongo-ovalis, ferrugineo-testaceus, nitidus, nudus, elytris testaceo nigroque liiieatis, prothoracis marginibus anterioribus et posterioribus anguste nigricantibus ; elytris crebre, subtiliter, sed distincte et sequaliter punctatis, stria discoidali iinpressa ; coxis posterioribus laevigatis, ab- dominis segmentis basalibus utrinque fortiter punctatis. Long. 3, lat. ll m.m. The only specimen I have seen of this species has the tarsi quite slender and is probably a female. It seems to be allied to Hydroporus pullus, Lee. (No. 321) but is very much broader. South America, (Parana). 108. 325. Hydroporus duponti, Aube, M.C. — Oblongo-ovalis, niger, supra in capita, thorace et elytris signaturis testaceis ; prothorace elytris angustiore, lateribus versus basin fere angustioribus, utrinque striola obliqua jjrofunda impresso, inter striolas transversim depressiusculo ; elytris versus suturam crebre fortiter, versus latera obsolete, punctatis ; corpore subtus nitido, coxis posterioribus fortiter punctatis. Long. 3 m.m., lat. 1? m.m. I have seen only a single individual — one of Aube's types — of this very distinct species ; I do not know its sex, the tarsi are not dilated, but the last ventral segment is prominent at the apex and foveolate. The form recalls Huxelhydrus syntheticus. The yellow marks on the upper surface are, a transverse line on the vertex, a yellow band across the thorax near the front, interrupted in the middle, and four or five, small, isolated markings on the elytra, all distant from the suture. Brazil, (Coll Mnizech). 1132. r. 23.— Genus HUXELHYDRUS. Prosternal process elongate, parallel-sided ; intercoxal process of metasternum not attaining the mesosternal fork ; hind tibiae with a distinct, slender, basal portion. Coxal lines shorter than the prosternal process. A single species, (and of that only two or three individuals) is known. 326. Huxelhydrus syntheticus, n. sp. — Niger, antennis pedibusque rufis, capite piceo, thorace elytrisque testaceis, thorace marginibus anterioribus et posterioribus nigricantibus, elytris indeterminate nigro-lineatis, dense obsolete punctatis, apice subtruncatis, utrinque obtuse angulatis, stria discoidali impressis ; corpore snbtiis dense sequaliter subtiliterque punctato. Long 3i, m.m., lat. !« m.m. I have seen only three individuals of this small but most interesting insect ; one, 370 On Aquatic Carnivorous Cokoptera or Dytiscidce. a very old individual was contained in Chevrolat's collection, with the label " Hydro- porus apicalis, Chev. Australia, bor." ; the other two were in Andrew Murray's New Zealand collection, labelled " nov. spec. New Zealand." The true habitat is there- fore still to be ascertained. Northern Australia ; (Mus. Chevrolat). New Zealand, (Mus. Murray). 100. I. 24.— Genus TYNDALLHYDRUS. Prothorax narrowed behind, prosternal process prevented by the contiguous and intervening middle coxse from attaining the metasternum. This is an autogenus of which only an unique individual is known. 327. Tyndallhydrus caraboides, n. sp. — Oblongo-ovalis, breviusculus, sine pubes- centia; dense punctatus, opacus, testaceus, elytris signaturis interruptis nigris ; prothorace valde transverso, elytris angustiore, posterius angustato, utrinque striga obliqua profunde impressa ; elytris densius sat fortiter punctatis ; coxis posterioribus fortiter punctatis; abdomine impunctato. Long. Z\, lat I5 m.m. I have seen but a single specimen of this species, and am uncertain about itssex„ the front tarsi are rather broad, though the joints are not at all dilated. Africa, (Algoa Bay). 445. II. 8. — Group Htphidrini. Hind coxal cavities separated, quite exposed, being not at all protected by the coxal processes, the apices of which are rounded t)r obtuse, and are closely ad- pressed to the level of the ventral segments. One genus — liyphydrus — is rather widely distributed in the eastern hemisphere^ and is well known by numerous species ; the other genera are all auto-genera^ confined to South Africa, and very rare in collections. Epipleura gra- ' dually nar- rowed liom [ — _ _ _ DARWINHYDRUS shoulder to ' ( Vide p. 373.) extremity. J On Aquatic Carnivorous Coleoptera or DytiscidcB. 371 'Prostemal "i process not I touching I metaster- I num. J Epipleura nar- rowed from shoulder to hind margin of first vent- ral segment; after that veiy slender and neces- sarily, thenre- fore, nearly parallel. Prostemal process touching metaster- num. Terminal joint of front tar- sus elongate ; intercoxal process of metasternum not connect- ing with me- sosternal fork. 'Last joint ofj front tar- sus about i as long as the third | joint. J Last joint of front tar- sus twice as long as third joint. L Terminal joint "l of front tar- sus short ; intercoxal process of me- [■ tasternum touching me sosternal fork. 'Elytra with- ovit definite genicular fossa. Elytra with definite ge- nicular fossa at shoulder of epipleura. . AKDEX ( Vide below). CCELHTDRUS {Vide p. 373.) PRIMOSPES {Vide -p. 372.) UYDROPEPLUS (Vide p. 372.) HYPHYDRUS (Vide]). 374.) I. 25.— Genus ^iVi)^X Prostemal process abbreviate ; its concealed extremity not extending outside the middle cox^, and not reaching the metasternum. Prothorax much narrower than the after-body, so that the outline at the shoulders is very interrupted. A single South African species is the only one yet known. 328. Andex insignis, n. sp.— Depressiusculus, subopacus, sine pubescentia, capite nigricante anterius ferrugineo, thorace ferrugineo, medio maculis duabus vage fuscis, elytris obscure ferrugineis, pectore abdomineque nigris, hoc apicem versus ferrugineo ; antennis pedibusque rufescentibus ; thorace elytrisque sparsim subtiliter punctatis, illo medio ante basin transversim depresso ; pectore abdomineque opacis sed vix punctatis. Long. 5i, lat. 3 m.m. TSAK9. BOT. DUB. SOC, U.S., TOI.. U. 372 On Aquatic Carnivorous Coleoptcra or Dijtii>cid(je. This species is very distinct by the prosternal process, and by the form of the thorax which is much narrower at the base than are the elytra. In the male the two basal joints of the front and middle tarsi are much dilated, the basal one beinor elongate as well as broad. Cape of Good Hope, (found by Drege). 1G8. 1. 26.— Genus HYDROPEPLUS. Terminal joint of front tarsus quite twice as long as the third joint ; head rounded in front; elytra at the shoulder of the epipleura with a fossa limited behind by a distinct raised line. 329. Hydroporus trimaculatus, Cast., M.C. — Ovatus, crassus, subdepressiusculus, dense subtilissime punctatus, opacus, sine pubescentia, supra tuscus, infra niger ; an tennis pedibusque obscure testaceis ; capite nigro in vertice macula minima ferruginea ; thorace ad latera paulo rotundato, marginibus late rufo-ferrugineis, macula oblonga ferruginea in medio postice notato ; abdomine rufo-nigro vel nigro. Long. 5i, lat. 3^ m.m. Mas, tarsis anterioribus et intermediis fortiter dilatatis, intermediorum articulo basali secundo evidenter latiore. Fern., tarsis anterioribus et intermediis sat dilatatis, intermediorum articulo basali secundo paulo latiore. Soiithevn Africa, (Cape Town, Caffraria). 1G7. I. 27.— Genus PRIMOSPES. Terminal joint of front tarsus quite twice as long as the third joint; head subtruncate in front ; the depression at the base of the elytral epipleura not limited behind by a raised line. A single South African species is the only one known. 330. Primospes suturalis, n. sp. — Ovalis, sub-opacus, subtilissime punctatus, sine pubescentia, niger, antennis pedibusque rufis, prothorace testaceo, medio maculis duabus fuscis, elytris fusco-testaceis, sutura margineque externo dilutioribus, lineis On Aquatic Carnivorous Coleoptera or Di/tiscidce. 373 duabus punctorum sat distinctis ; prothoracis angulis posterioribus acutis. Long. 4|, lat. 2 J m.m. Mas, tarsis anterioribus et intermediis valde dilatatis. Fern., tarsis anterioribus et intermediis latis. This species has a good deal the form and appearance of a Laccophilus ; the excessively fine punctuation is an important diagnostic of the species. South Africa, (Cape Town). 169. I 28.— Genus CCELHYDRUS. Epipleura much narrowed from the shoulder to the hind margin of the first ventral segment, behind that very slender, and therefore necessarily nearly parallel. Last joint of the front tarsus about as long as the third joint. Prosternal process reaching intercoxal process of the metasternum. A single South African species is the only one known. 331. Coelhydrus brevicollis, n. sp. — S Ovalis, crassiusculus, parumelongatus, subtus convexus, supra sparsim punctatus, ferrugineus, capite thoraceque nitidis, elytris subopacis, pectore nigricante ; coxis posterioribus sparsim sat fortiter punctatis ; tibiis posterioribus calcaribus subsinuatis. Long. 3|-, lat. 2i m.m. This species has much the form of Dytiscus confluens {No. 423), but it is larger, more strongly built, comparatively a little broader, and more convex. The three individuals before me, appear all to be males, the front and middle tarsi are rather short, broad, and flat, the basal joint of the front ones is distinctly, of the middle ones strongly dilated. The head has no trace of margin in front, and has only a very scanty punctuation. The thorax is sparingly punctured along the base, almost without punctuation along the middle ; the punctures on the elytra are distant from one another and not coarse, and have some finer very obsolete punctures mixed with them. South Africa, (Port Elizabeth, 28th February, 1875, Geo. Lewis). 1138. L 29.— Genus DARWINHY DRUS. Epipleurse of elytra becoming narrower in a regular and gradual manner from the shoulder to the extremity ; outline of thorax and elytra quite continuous, the latter acutely costate. A single peculiar South African species* is the only one known. * It is just possible this may be an Australian species. 3 C 2 374 On Aquatic Carnivorous Colcoptera or Dytiscidce. 332. Darwinbydrus solidus, n. sp. — Latus, sat convexus, fere opacus, sine pubes- centia, ferrugineus, supra fusco-testaceus, fortiter punctatus, elytris costis tribus elongatis elevatis. Long. 3|, lat. 2i m.m. Head broad and short, rather ooarsely punctured, the clypeus completel}^ rounded in front and finely margined. Thorax very short, very closely adapted to the base of the elytra, the lateral margins strongly elevated, moderately coarsely punctured. Elytra with large distinct punctures rather closely placed, and each with three elevated ribs, the inner one placed at a considerable distance from the suture, the outer one rather near to the pleural margin and curved so that it joins the inner line close to the extremity of the elytra, the middle rib does not join the others. Coxae coarsely, moderately closely, punctured. I have seen only one individual, of whose sex I feel doubtful. South Africa, (Cape Town). 188. I. 30.— Genus HYPHYDRUS. Tntercoxal process of metasternum obscurely but decidedly connected with the mesosternum : its extremity being turned upwards so that it rises into the mesoster- nal fork. Terminal joint of the front tarsus very obscure and but little exserted from the third joint. This genus consists at present of about twenty-five species* ; they are very simi- lar to one another, and their determination is not easy ; no doubt many more species exist undescribed and an attempt to discriminate by means of a table the species here described would not be likely to prove of use. The punctuation of the wing- cases is very useful for distinguishing many of the species ; it consists often of a double punctuation viz, (o) coarse and few, (6), fine and numerous, punctures; the com- parative development of these two forms of punctuation .should be noticed. The distinctive characters of the sexes are also very important aids. The species do not occur in the Xew World. * In addition to these the following descriptions probably refer to species of this genus. Hydroporus tifasciatus, Macl. (No. 1345 huj. op.) ? = No. 358 ; Australia. — Hydroporus coquereli, Fairm. (No. 1355), ? = No. 34G; Madagascar. — Hyphydrus caffer, Boh. (No. 1460) ; CafTraria. — Hyphydrus circumflexus, Klug, (No. 1462), near No. 345; East Africa.— Hyj.hydi-us illigeri, Perrd. (No. 1465)1 = No. 358; New Caledonia. — Hyphydrus higubris, de Borre. (No. 1467) ; Sinai. — Hyphydrus maculatus, Bab. (No. 1468) ; ? South America. The genus to which the following two descriptions should be referred is doubtful, Hyphydrus austro-caledonicus, Perrd. (No 1459) ; New Caledonia. — Pachytes elegans, Mont. (No. 1499) ; New Caledonia. On Aquatic Carnivorous Coleoptera or Di/liscidcB. 375 :^33. Hyphydrus grandis, Cast. M.C.— Ovatus, brevis, crassus, thorace basi elytris angustiore, dense punctatus, rufescens, thorace antice et postice nigro, elytris irre- gulariter nigro-signatis, stria discoidali basi distincta. Long. 6, lat. 4 m.m. Man, nitidulus, fortiter punctatus, tarsis 4 anterioribus deplanatis, trochan- teribus anterioribus valde elongatis. Fern., subopaca, sat fortiter punctata, tarsis 4 anterioribus comprcssis, trochan- teribus anterioribus brevibus. In this species and H. major, the front legs are more elongate, and the outline of the body is much interrupted at the junction of the thorax and after body. Africa, (Gaboon). 26. 334. Hyphydrus major, n. sp.— Ovatus, latus, sat brevis, thorace basi elytris multo angustiore, dense, oequaliter, sat fortiter punctatus, rufescens, thorace antice et postice nigro, elytris irregulariter nigro-signatis, stria discoidali sat distincta. Long. 6i, lat. 4 m.m. Ma,s, nitidulus, fortiter punctatus, tarsis 4 anterioribus deplanatis, trochanteribus anterioribus valde elongatis. Fein., subopaca, minus fortiter punctata, tarsis 4 anterioribus compressis, trochan- teribus anterioribus brevibus. Differs from H. grandis, only by the rather more elongate form, the rather longer and thinner front legs, and slightly more even and finer sculpture. The sexual characters are quite the same, and I cannot feel sure whether this be more than a local form of H. grandis. Lower Egypt, and "Nubia. 27. 335. Hyphydrus parvicollis, n. sp. — Ovalis, sat latus, valde convexus, ferrugineus, thorace antice et postice nigro, elytris nigro-signatis, thorace parvo, basi elytris angustiore; fortiter crebre, sequaliter punctatus. Long. 5, lat. 3 m.m. Head small, rather coarsely and closely punctured. Thorax very transverse, the sides strongly oblique, of a dark yellowish colour, black in front and behind, rather coarsely and moderately closely punctured. Elytra rather coarsely punctured, the punctures rather close, much finer towards the sides, the punctures, except for this, are all of one size ; they are of a yellowish or tawny colour, black along the suture, outside this with a black band, and external to this with one or two other black marks. The under surface is reddish and shininc ; the prosternum bears on the front a small acute tubercle. I have seen only three individuals of this species, they all agree exactly, and are I believe males, though they have the tarsi slender, the joints compressed laterally and not dilated ; the shape of the front tibia is ^^eculiar, it is slender, and on the inner side is slightly dilated above the middle, and thence obliquely narrowed to the knee. Gaboon ; found by Henri DeyroUe. 28. 37 , Tangiers, and formerly found at "Vienna. 39. On Aquatic Carnivorous Coleoptera or Dytiscida. 381 341). Hyphydrus japonicus, Sharp, Tr. Ent. Soc. Lond. 1873, p. 54. — Ovalis, latus, convexus, testaceus, thorace basi, elytrisque fusco-signatis, vertice maculis duabus parvis fuscis ; elytris stria discoidali ad basin sat distincta, sutiirali subobsoleta. Long. 43, lat. 3 m.m. Mas, nitidulus, crebre inoequaliter punctatus, tarsorum quatuor auticorum articulo basali posterius valde (prsesertim intermediorum) dilatato, abdominis segmento basali medio tuberculo crasso subelevato. Fern., pedibus paulo magis gracilibus, (a.) ut in mare nitidula subtilius punctata ; paulo minor. (b.) opaca, obsolete punctata ; evidenter minor. In this species the sculpture of the elytra consists of large and small punctures mixed together, the large ones are rather numerous and are conspicuously diiferent in size from the smaller ones, which are very fine ; the ground colour in this species is a peculiar clay yellow, on which the dark markings are displayed in a very con- spicuous manner. Japan. 40. 350. Hyphydrus frontalis, n. sp. — Ovalis, latus, convexus, nitidus, confertim, fortiter, inaequaliter punctatus, ferruginous, vertice maculis duabus minutis et prothorace basi medio fuscis ; elytris testaceis fusco-signatis, stria discoidali ad basin sat distincta, suturali subobsoleta. Long. 4i, lat. 3 m.m. Mas, tarsorum quatuor anticorum articulo basali posterius valde (prsesertim intermediorum) dilatato, abdominis segmento basali medio vix tuberculato. Fern., paulo minor, pedibus paulo magis gracilibus. This species is much allied to the H. japonicus, but the ground colour is redder, and the punctuation is rather coarser, which is especially to be remarked when the fine punctures of the elytra in the two are compared ; the basal segments of the hind body are finely punctured on the middle. Japan. 41. 351. Hyphydrus Iseviventris, n. sp. — OvaHs, latus, convexus, nitidus, sat confertim, iniBqualiter punctatus, punctis majoribus (elytrorum) conspicuis, ferruginous, prothorace basi medio elytrisque fusco-signatis, his stria discoidali ad basin sat distincta, suturali fere omnino nulla ; abdomine medio laevi, impunctato. Mas, tarsorum quatuor anticorum articulo basali sat dilatato ; major. Long. 5, lat. 3i m.m. Fern., pedibus paulo magis gracilibus, minor. Long. 4^ m.m. In this species the large punctures of the elytra are strongly developed so as to be in conspicuous contrast with the finer ones : though extremely similar to H. 3 D J 382 On Aquatic Carnivorous Coliuplcra or /-'yti.scida;. japimicus, and H. frontalis, this species is easily distinguished when the two are compared by the more slender and elongate third joint of the front tarsi, this difference beingf more striking;' in the males than in the females. Japan. 42. 'A52. Hyphydrus oiientalis, Clk., M.C. — Ovalis, latus, convexus, nitidus, confertim fortiter subinggqualiter punctatus, ferrugiueus, supra rufo-testaceus, prothorace basi medio elytrisquo fusco-signatis, his stria discoidali ad basin sat distincta, suturali subobsoleta ; abdomine segmentis basalibus medio subtiliter punctatis. Long 43, lat. vix 3 m.m. Mas, tarsorum quatuor anticorum articulo basali sat dilatato ; abdomine segmento basali medio macula rotunda, opaca (?glandulifera). Fern., paulo subtilius punctata, pedibus paulo magis gracilibus. This species in its general appearance much resembles H. frontalis, (No. 350), but the male tarsi are similar to those of H. Iseviventris. Although I have not been able to examine the tarsi of the specimens in the British Museum of Hyphydrus eximius, and H. pulchellus, Clark, I believe they will prove to belong to this species. China, (Kiu-Kiang). Also from Formosa ; tlie specimens from this locality are rather more coarsely and distinctly punctured on the elytra, but as the structural and sexual characters seem to be quite the same as in the Chinese specimens, I cannot consider them a distinct species. 43. 353. Hyphydrus indicus, n. sp. — Ovalis, brevis, .sat convexus, testaceus, prothorace nigro, laterihus late testaceis, elytris nigro-signatis, pectore abdomineque fuscescentibus, tarsorum articulo tertio nigricante ; dense sequaliter punctatus, parum nitidus, elytris stria discoidali sat distincta. Long. 4, lat. 2l m.m. Mas, tarsis quatuor anterioribus angustis ; trochantei'ibus anterioribus parum profunde mcisis sed extus spina tenui fere recta armatis ; abdomine segmento apicali apice transversim tuberculato. The single individual I have seen of this species indicates it as being very distinct from the others known to me : its form, size, rather dull surface and narrow simple tarsi, would lead one t(j think the male to be rather the other sex, but on careful comparison the characters point it out as allied to H. lyratus, and H. xanthomelas, but undoubtedly connecting them with the African H. crassus and its allies. The close even punctuation is similar to that of the corresponding sex of H. lyratus and H. xanthomelas, while by the structure of the trochanteis it approaches the African species ; the front and middle tarsi are less compressed than in fl. crassus, but much less flat and broad than in H. lyratus and H. xanthomelas, from which species it also departs by its considerably shorter form. East India, (ex. coll. Murray). 1 1 25. On Aquatic Carnivorous ColeojJtera or Dytiscidce. .S83 354. Hyphydrus lyratus, Schartz, M.C — Oblongo-ovalis, sat latus et convexus, dense aequaliter punctatus, subtus ferrugineus, supra rufo-testaceus, prothorace basi medio nigricante, elytris longitudinaliter fusco vel nigro-signatis, stria discoidali ad basin sat distincta. Long. 4^, lat. 3 m.m. Mas, fortiter punctatus, sat nitidus, tarsis quatuor anterioribus dilatatis et deplanatis, abdomine segmento baaali medio spina crassiuscula oblique erecta, segmento apicali medio quadrato-impresso, apice summo bi-denticulato. Fern., anterius angustior, opaca, subtiliter punctata, elytris versus latera fovea elongata impressa. This species ajij^ears to be a variable one. Hyphydrus nigro-notatus, Clk., is the Formosan variety of the species. Australia, Formosa, China, New Guinea, Pulo-penang. (Sidney, Port Denison, North- West Australia ; Dorey). 44. SS."). Hyphydrus xanthomelas, Regt. Ann. Soo. Fr. 1877, p. Ixxx. — Oblongo- ovalis, sat latus et convexus, piceus, capite et prothoracis lateribus ferrugineis, elytris nigricantibus testaceo-signatis, dense sequaliter punctatus, elytris stria discoidali ad basin sat distincta. Long. 4^, lat. 2| m.m. Mas, fortiter punctatus sat nitidus, tarsis quatuor anterioribus sat dilatatis et deplanatis ; abdomine segmento basali margine posteriore medio acute denticulato, apicali medio leviter longitudinaliter inipresso, apice summo bi-denticulato. Fern., r This species is very closely allied to IL lyratus, but the intermediate tarsi are not so much dilated, and the male sexual abdominal characters are less developed ; the darker colour is perhaps not constant ; indeed M. Regimbart's description indicates an insect less marked with black than the one I have described — the only one I have seen. Philippine Islands, (ManDla). 45. 356. Hyphydrus decem-maculatus, Wehncke, Stet. Zeit. 1877. p. 151. — An^uste ovalis, sat convexus, piceus, capite ferrugineo plus minusve infuscato, elytris ferrugineo-maculatis ; confertira fortiter aequaliter punctatus, elytrorum stria discoidali obsoleta. Long. 4^, lat. 21 m.m. Mas, trochanteribus anterioribus valde elongatis, subtus sinuatis, dextro apice acuminate, sinistro apice dilatato ; tarsis anterioribus leviter, intermediis fortiter dilatatis et deplanatis. Fern., paulo minor, pedibus simplicibus. This species is variable in the colour. The structure of the male trochanters, which is different on the two sides of the body, is highly remarkable. Australia, (Cape York, Rockhampton). 46. 384 On Aquatic Carnivorous Cohoptera or Dytiscida;. 357. Hyphydrus contiguus, Wehncke, Stet. Zeit. 1877, p. 150.— Anguste ovalis, sat convexus, testaceo-ferrugineus, elytris nigris testaceo-signatis, confertim fortiter aequaliter puuctatus. Long. 3|, lat. 2^ m.m. Mas, trochanteribus anterioribus elongatis, subtus sinuatis ; tarsis anterioribus et intermediis dilatatis. This species is very closely allied to Hyphydrus decem-maculatus, but is smaller, and different in colour. The coxa? are more densely punctured, and the front tarsi of the male are a little more dilated. I have seen but a single male of the species, and have not been able to see exactly the form of the front trochanters. Australia. 157. 3.58. Hyphydrus australis, Clk. M.C. — Oblongo-ovalis, sat latus et convexus, nitidus, infra colore variabilis, supra rufo-testaceus, prothorace basi medio elytris- que nigro- vel fusco-signatis, confertim, aequaliter fortiter punctatus, elytris stria discoidali ad basin vix distincta, suturali subobsoleta. Mas, tarsis anterioribus fortiter dilatatis, subdeplanatis, articulo tertio quam basali fere latiore ; intermediis subdilatatis, lateraliter compressis. Long. 5, lat. 3 m.m. Fern., pedibus minoribus, tarsis simplicibus. Long. 4^ m.m. Though the male of this species a good deal resembles the male of H. lyratus^ the two species are found to be very distinct when the corresponding sexes of each are compared together. The structure of the front tarsi in the male of the present species is peculiar, the second joint is of an irregular, somewhat rhom- boidal form, and when the soles are looked at it is seen that the posterior portions of the second and third joints are on a different plane to the anterior portions, and that only the anterior portions of these two joints are clothed with tomentum. Australia, (apparently throughout), New Oaledouia. 47. I. 31.— Genus STERNOPRISCUS. Anterior and middle tarsi with the fourth joint distinctly visible between the third and fifth joints. Mesosternum intervening in a conspicuous manner between the pro- and metasternum, its epimera extremely short, almost linear; ventral seg- ments not soldered with the coxse. Hind coxal cavities not contiguous but pro- longed inwards over the coxal process, so as to become nearly connected by these prolongations. On Aquatic Carnivorous Coleoptera or Dytiscidce. 385 The species are best distinguished by the sexual characters, which are frequently- extraordinary ; the males of some species are twice the bulk of the females, and may be the possessors of extraordinary structures on their antennae and middle legs. They are peculiar to Australia.* 359. Sternopriscus browni,n.sp. — Oblongo-ovalis,subopacus, dense siibtiliter punc- tatus subtiliterque pubescens, nigricans, capite fusco obscure testaceo-maculato, prothorace testaceo medio late infuscato, utrinque striga impressa, elytris fuscis indistincte testaceo-raaculatis, antennis pedibusque fusco-testaceis ; corpore subtus dense gequaliterque punctate. Mas, major, (long. 3s m.m.) antennis articulis 2 et 3 elongatis, 4 et 5 brevibus, 6 sat elongate, 7-11 distortis ; tibiis anterioribus leviter curvatis, intus emarginatis ; pedibus intermediis elongatis, femoribus longius ciliatis, tibiis curvatis, tarsis articulis 4 et 5, (4° magno, 5" dilatato) externe spongiosis interne glabris; tarsis posterioribus crassis utrinque longius ciliatis. Fern., minor, (long. 2| m.m.) antennis pedibusque simplicibus. Head very finely but somewhat closely punctured, fuscous but with some indistinct spots on the front, and a still more indistinct one on the vertex, yellowish. Thorax and elytra densely and finely punctured ; sides of the thorax nearly straight, the middle of the base forming a very evident angular projection. Elytra rather rounded at the sides, and deflexed towards their apex which is rather pointed. Avistralia, (King George's Sound). Given by the lamented Edwin Brown. 159. 360. Sternopriscus obscurus, n. sp. — i>, Ovalis, opacus,densesubtilissimepunctatus subtiliterque pubescens, nigricans, capite, prothorace, antennis pedibusque obscure fusco-rufis ; corpore subtus dense, sequaliter, subtiliterque punctate. Long. 3 m.m. I am only acquainted with the female of this species, which is very similar to the female of S. browni, but differs as follows : S. obscurus is rather larger and broader, and more obscurely coloured, and rather more finely punctured, and the antennae and the apical joints of the front and middle tarsi are more elongate. The male will probably prove to have some difference in its sexual characters from those of S. browni. Australia, (King George's Sound). 160. • In addition to the ten species of which descriptions follow, there is yet another that should be included in the genus, viz., Hydroporus hansardi, Clk., (No. 1,37G huj. op,), near No. 361. 386 On Aquatic Carnivorous Coleoptera or Dytiscidce. 361. Sternopriscus clavatus, Wehnckc, n. sp. — Ovalis, sat angustus, sub-opacus, dense subtiliter punctatus, brevissiineque pubescens, rufo-testaceus, pectore infuscato ; prothoraco marginibus aaterioribus (in medio) et posterioribus nigris, striga utriuque obsoletissima ; elytris nigricantibus, testaceo-maculatis ; auteanis in medio fuscis; elytrorum apice subobtuso. Mas, major (long. 4 m.m.) antennis ultra medium distortis ; tibiis anterioribus curvatis ; pedibus intermediis leviter elongatis, tarsis crassiusculis Fern., minor (long. 3^ m.m.) antennis tibiisque simplicibus. Australia, (Sidney). 161. 362. Sternopriscus tarsalis,n. sp. - Ovalis, angustulus, sub-opacus, testaceus, pectore obscuriore, vertice prothoracisque medio infuscatis, elytris fuscis macidis parvis irregularibus testaceis ; elytris thoraceque dense subtiliter punctatis, hoc utrinque plica distincta, corpore subtus dense punctato. Long. 2|, lat. If m.m. In this species there is no trace of any constriction across the middle of the thorax, the base of which is quite as wide as the elytra, the plica on each side is distinct, but not strongly elevated, and there is no transverse depression between the two. The only individual 1 have seen of this species is I have no doubt a male. The front tibiae are curved, the front tarsi are distinctly 5-jointed, the three basal joints being dilated ; the middle legs are long, their tibiae slightly curved and their tarsi greatly elongate, the five joints of these are very distinct, the 4th being about as large as the third ; the antennae are rather elongate and slender. Australia, (Sidney). 1 62. 363. Sternopriscus signatus, n. sp. — Ovalis, subopacus, testaceus, prothoracis marginibus anterioribus et posterioribus anguste fuscis, elytris nigro-testaceoque variegatis ; prothorace lateribus rectis, utrinque plica minus distincta, medio obsolete transversim depresso ; corpore toto dense subtiliter punctato, elytris subtiliter pubescentibus. Long. 2^, lat \\ m.m. This species is allied rather closely to Sternopriscus tarsalis, but is smaller and less elongate, and the yellow colour is more predominant, and the punctuation is somewhat denser and finer. I do not Isnow the sex of the only individual I have seen ; it has the front tibiae rather short but simple, the three basal joints of the front tarsi dilated, the fourth joint short but distinct, the fifth moderately long ; the middle tibiae are rather stout, the basal joints of their tarsi dilated, the fourth joint distinct but not elongate, Oil Agnatic Carnivorous Coleoptera or Di/tiscidce. 387 the fifth rather long; the anteniite are slender and quite simple; altogether it is highly probable that this is the female. Australia, (Murray River). 1G3. 364. Hydroporus meadfooti, Clk., ^l.G. — Ovalis, subopacus, nigricans, capite fusco obscure testaceo-maculato, prothorace lateribus rufis, medio fusco, elytris fuscis vage testaceo-maculatis, antennis fusco-testaceis, pedibus obscure testaceis ; prothorace utrinque plica bene elevata, inter plicas transversim sat depress© ; corpore dense subtiliter punctato, elytris evidenter subtiliter pubescentibus. Long. 2], lat. li m.m. ^las, prothoracis lateribus rectis ; antennis paulo elongatis medio leviter incrassatis ; tarsis anterioribus articulis basalibus bene dilatatis ; tarsis intermediis elongatis, articulis basalibus sat dilatatis. Fcm., paulo minor, prothoracis lateribus pone medium vix distincte constrictis, antennis gracilibus, tarsis anterioribus ct intermediis articulis basalibus sat dilatatis ; tarsis intermediis baud elongatis. Australia, (Melljourue). IGl. 365. Hydroporus multimaculatus, Clk., M.C. — Ovalis, subopacus, testaceus, ab- domine pectore thoracis medio elytrorumque maculis numerosis nigricantibus; elytris dense subtiliter sed subscabroso puuctatis, brevissime pubescentibus ; prothorace utrinque plica valde elevata, inter plicas transversim depresso. Long. 2i, lat. li m.m. Has, prothoracis lateribus rectis ; antennis paulo elongatis ; tarsis anterioribus articulis basalibus bene dilatatis. Fern., prothoracis lateribus medio constrictis, antennis simplici bus ; tarsis an- terioribus articulis basalibus minus dilatatis. This species is ea.'sily recognized by the peculiar dense rough punctuation of the elytra. The female was described by Ciark as a distinct species under the name of Hydroporus sinuatocollis. Australia, (Adelaide and West Australia). 165. 366. Sternopriscus wehnckei, n. sp. — Ovalis, subopacus, testaceus, pectore ab- domine vertice prothoracisque medio elytrisque fuscis, his maculis parvis irrcgularibus testaceis ; antennis fusco-testaceis, basi dilutiore ; prothorace utrinque plica, bene elevata, medio leviter transversim impresso ; corpore dense subtiliter punctato, elytris subtiliter pubescentibus. Long. 2i, lat. li m.m. TRANS. KOT. DUB. SOC, N.S., VOL. II. 3 E 388 On Aquatic Carnivorous Coleoptera or DijtiscidiP. Mas, antennis apicem versus incrassatis ; tibiisanterioribus leviter curvatis, tarsis articulis basalibus fortiter dilatatis ; tarsis intermediis clongatis, articulis basalibus subdilatatis. Fem., antennis ijracilibus ; tarsis auterioribus et intermediis basi sat dilatatis. Intermediate between Sternopi'iscus tarsalis, and H3'droporus multimaculatus (No. 365), smaller than the former, and with the antennae of the male not so long, and the middle tarsi much less elongate : rather broader than Hydroporus multimaculatus, with the yellow colour more predominant on the head and thorax, the sculpture of the elytra not quite so fine ; with the antennae of the male having the apical joints thicker than the middle ones, and the intermediate tarsi a good deal more elongate. Australia, (received from Herr Welmcke). IGG. 367. Sternopriscus oscillator, n. sp. — Ovalis, subopacus, densissime punctatus, niger, supra testaceo nigroque irregulariter variegatus, pedibus testaceis, antennis basi testaceo, apice fusco ; prothorace utrinque plica bene elevata, medio leviter transversim impresso. Long. 2f, lat. If m.m, $. Mas, major, antennis longioribus, fere simplicibus, tibiis auterioribus leviter curvatis, tarsis evidenter . 5 -articulatis, articulis basalibus dilatatis; tarsis intermediis elongatis articulis basalibus leviter dilatatis. Fcm., antennis gracilibus brevibiis, tarsis auterioribus et intermediis brevioribus basi fortiter dilatatis. Allied to S. wehnckei, but witli the sexes more different ; the male is larger and more elongate than in that species, and the antennae are more elongate and appear therefore less thickened towards the apex, the front tarsi are larger and more distinctly 5-jointed, and the middle legs are considerably longer and thicker. The female is much more like S. wehnckei but the upper svirface is of more obscure colour, the form is narrower, and the surface not so dull. Axistralia, (Adelaide). 1133. 36S. Sternopriscustasmanicus,n.sp. — Oblongo-ovalis,subopacus,densiuspunctatus, niger, supra testaceo-varicgatus, prothoi'ace lateribus late testaceis; hoc utrinque plica sat elevata, ante basin in medio deprcsso ; antennarum basi j^edibusque testaceis; antennis versus apicem incrassati.s, articulo ultimo prcesertim latiore, angulo apicali interne producto acuto, tibiis anterioribus intus minute emarginato, tarsis evidenter 5 -articulatis, articulis 3 basalibus dilatatis; pedibus intermediis elongatis, parum crassis, tarsis elongatis, superne longe ciliatis. Long. 21, lat. \h m.m. T have seen only a single male of this species ; it may be readily recognized by the peculiar incrassation of the terminal joint of the antennas. Tasmania. 1134. On Aquatic Carnivorous Colcoptera or DytiscidcB. 389 II. 9. — Group Htdroporini. Front and middle tarsi 4-jointed (with a small additional joint occasionally visible at the base of the terminal joint) ; mesosternum but little visible, being placed at such an angle with the metasternum that it is much concealed between this and the prothorax : hind coxal cavities nearly or quite contiguous; ventral segments not soldered to coxe&; prosternal process acuminate behind. There are ten genera comprised in the Hydroporini. I find it difficult to make a dichotomous key that woukl be practically useful for their identification, and have therefore drawn up the following series of abbreviated characters ; these can be glanced through in a few minutes and the genus in this manner ascertained with certainty. Elytral ligula free and abrupt, terminal joint of front tarsus very sliort in 1 comparison witli tlio third joLut. Three species from the eastern \ portion of the INIediterrauean region. J HYPUOPORUS. (Vide^. 390.) Elytral ligida free, ahrupt, terminal joint of front tarsus not very sliort in ] comparison with the third joint, although often much concealed by | CCELAMBUS. the deep fissure of the latter. Numerous species in the European and j {Vide \). 394.) North American regions. J Elytral ligida abrupt on the posterior fiice, gradually raised in front ; hind ] coxal cavities approximate ; posterior portion of epipleuras very .narrow ; humeral area of epipleura limited behind by a well-marked raised line. Six sjiecies, extending from Madagascar to Southern Europe. J Elytral i-idge very little developed ; posterior coxal cavities much exposed and a good deal sej^arated ; posterior portioir of epipleura veiy narrow ; hind tibia with only the serial punctures on the infero-extemal face. Three species peculiar to Australia. Elytral ligula absent ; posterior portion of epijileura comparatively Ijruad ; ") hind tibia with only the serial ^junctures on the infero-external ftice ; | posterior femora slender, with rounded outer angle. Four species f found in Australia and Tasmania. J Posterior portion of epipleura comparatively on the infero external aspect ; the trii scarcely visible. Eight species found in Australia and New Zealand. J jroad ; hind tiljia [iimctured "I the true foui-th joint of front tarsus j- True fourth joint of front tarsus quite conspicuous, distinctly disengaged ^ from the lobes of the third joint : (this structure more exaggerated in ! the males than in the females). Eight species found in Australia and , Tasmania. J Hmd tibia only with serial punctures on the infero-external aspect. Terminal poi-tion of epipleura rather broad : posterior femora stout ; their postero-external angle sharply defined. Six species found in Australia and Tasmania. IIEROPHYDRUS. {Vide IX 392.) PAROSTER. {Vide^. 391.) CIIOSTONECTES. {Vide\x 408.) ANTIPORUS. {Vide IK 410.) NECTEROSOMA. (Fj'rfep. 412.) MACROPORUS. {Videp. 416.) 3 E 2 390 On Aquatic Carnivorous Coleoptera or Dijtiscidu;. No ligula on inner face of elytrou ; terminal portion of epipleura narrow ; "] Immeral area of elj'tra not limited Ijeliind by a raised lino. Fifty i DERONECTES. species, princii)ally inliabiting the European and Mediten-anean region, [ (Vide vi. 418.) with a few in the nortliern half of America. J Mesosternal fork connected with the intercoxal process of metasternum ; "| (in all the preceding genera of Hydroporini this connection does not 1 IIYDROI'OECS exist.) One hundred and fifty species, nearly all peculiar to the j" (TiWep. 43.5.) European and North American regions. J I. 32.— Genus HYPHOPOIWS. Ligula on inner fixce of elytron abrupt and prominent. Terminal joint of front tarsus very short in comparison with the third joint. Mesosternal fork not con- nected with intercoxal process of metasternum. The three species * have much the appearance of the Hyphydri, to which genus they are allied by the tarsal structure. They are all Asiatic, but one extends to Egypt. 369. Hyphoporus elevatus, n. sp. — Ovalls, crassus, brevis, convexus, ferrugineus ; elytris vage nigro-signatis, punctis majoribus et minoribus dense munitis, majoribus ad apicem disinentibus ; corpore subtus grosse punctate. Long. 4f, lat. 3 m.m. This species has quite the thick convex form of a Hyphydrus, but structurally it is closely allied to Hydroporus soheri, (No. 371). The only individual I have seen is, I believe, a male, the front and middle tarsi are short and broad, the three basal joints being of about one width ; the apical joint is very short. Northern India, (found l.y Captain Boyd). 172. 370. Hyphoporus aper, n. sp. p. — Ovalis, brevis, latus, convexus, ferrugineus, sine pubescentia, opacus, prothorace basi elytrisque fusco-signatis, his fortiter profundeque punctatis ; corpore snbtus fortiter punctate. Long. 3|, lat. 2| m.m. This species has much the appearance of a rotund Hyphydrus, it is similar to Hydroporus solieri, but is readily distinguished by its much shorter form, and the coarser punctuation of the elytra. The only individuals T have seen are females. Northern India. 173. * The following two species .should also pretty certainly be referred to Hyphoponi.s. Hydroporus interpulsus. Walk., (No. 1387); Ceylon.— Hyjihydrus rufus, Clk., (No. UG9), near No. 371 ; China. Oil Aquatic Carnivorous Coleoptera or Di/tiscitke. 39 L 371. Hydroporus solieri, Aubc, M.C. — Ovalis, sat brevis, convexus, sine pubes- centia, testaceus ; elytris lineis quatuor pluries valde interruptis nigris, dense punctatis; corpore subtus fortiter punctate. Long. 5, lat. 3 m.m. 3fas, supra fortiter punctatus sat nitidus, tarsis anterioribus et intermediis fortiter dilatatis, tibiis intermediis ad basin angustis, dimidio inferiore lato iutus sub- angulatim dilatato. Fern., subtiliter punctata opaca, pedibus simplicibus. This species varies greatly as to the black markings, which are sometimes nearly entirely absent. Egypt, Persia, Arabia, Northern India. 174. I. 33.— Genus PAROSTER. The longitudinal ridge on inner face of wing-case very little developed ; posterior coxal cavities much exposed and a good deal separated; posterior portion of epipleura very narrow ; hind tibia with only the serial punctures on the infero- external face. Mesosternal fork not connected with the inter-coxal process of metasternum. The three species have the hind coxal cavities more exposed and separated than any other Hydroporini, and in this respect approach Bidessus of the Bidessini. They are found in Australia. 372. Hydroporus nigro-adiimbratus, Clk., j\f.C. — Ovalis, convexus, sine pubescentia, nitidus, fuscu.s, antennis, pedibus, tliorace in medio et ad latera elytrisque testaceis ; prothorace anterius et postering subtiliter punctato, medio impunctato ; elytris parce, subtiliter sed evidenter punctatis ; corpore subtus fere impunctaco ; tibiis anterioribus apicem versus latis. Long. 3f, lat. 2 m.m. Mas, tarsis anterioribus dilatatis, unguiculis valde elongatis. I have seen but a single individual of the species. Australia, (Adelaide). 419. 373. Paroster pallescens, n. sp. — Ovalis, convexus, sine pubescentia, vix nitidus, fuscus, supra cum antennis pedibusque testaceus, capite magis obscure ; thorace elytrisque sparsim subtilius punctatis ; corpore subtus fere impunctato ; tibiis anterioribus versus apicem latis. Long. 3f, lat. vix 2 m.m. .■)D2 On Aquatic Carnivorous ColeojAcra or Jhjtiscidce. This species at first sight exactly resembles Hydroporus nigro-adumbratus, (No. 372) but it has the punctuation of the upper surface less ; the only individual I have seen, I judge, from its short broad front tarsi, to be a male ; the claws are quite small. West Australia. 420. 374. Hydroporus insculptilis, Clk., M.C. — Ovalis, convexus, sine pubescentia, uitidus, piceas, capite pedibus antennisque rufis, his versus apicem fuscis ; thorace elytrisque sparsim subtiliter punctatis ; coxis posterioribus fere impunctatis. Long. 2i, lat.l.^i m.ra. I have seen but a single individual of uncertain sex, it has the front tarsi moder- ately broad. The species has the front tibiie more slender than the two preceding species, and has quite the appearance of a small Hydroporus such as H. melanarius (No. 555). Australia, (Victoria). 421. I. 3A.— Genus HEROPBYDEUS. Elytral ridge gradually raised till near the extremit}', then suddenly diminishing ; hind coxal cavities approximate ; hind portion of epipleura very narrow, humeral area limited behind by a well marked raised line. Mesosternal fork not connected with the intercoxal process of the metasternum. Only six species are known, they inhabit Madagascar and continental Africa, and one extends its range to southern Europe. 375. Herophydrus heros, (Dej.) n. sp. — Sat angustus, convexus, nitidus, piceus elytris rufo-signatis, crebre fortiter puuctatus, antennis jDedibusque rufis ; clypeo immai'ginato, thoracis angulis posterioribus obtusis. Long. 6, lat. 3i m.m. The head is finely and moderately sparingly punctured, rather paler in colour than the other parts. The punctures of the thorax are coarse and numerous. The el3't)a also are evenly and rather coarsely punctured ; the red marks on them are variable, and consist chiefly of a larger irregular mark near the shoulder, and a smaller one near the apex, with one or two otliers near the outer margin between them. The On Aquatic Carnivorous Colcoptera or Dytiscidce. 393 coxse, except their hind niai-gin, bear very coarse punctures, as do also the latera parts of the metasternum ; the ventral segments are also rather coarsely punctured. Madagascar. Gl. 376. Herophydrus verticalis, n. sp. — Latior, parum elongatus, convexus, piceus, sat nitidus, prothorace transversim in medio elytrisque lateribus obscure pallido- signatis, antennis pedibasque fusco-testaceis ; thorace elytrisque crebre fortiter sequaliter punctatis ; clypeo conspicue marginato, margine in medio parum interrupto. Long. 43, lat. 3. m.m. This species is remarkable for its appearance, which is quite that of a Hyphydrus, its tibice and tarsi are slender, and the small size of the later suggest it as approaching Hydrovatus, but so far as I have been able to examine, it undoubtedly is allied to Herophydrus spadiceus and Hyphydrus guineensis, Aube, (No. 378). I have seen but one individual which is very fragile and mutilated ; and I do not know its sex. It is much broader and a little longer than Hyphydrus guineensis, audits head and thorax are rather more regularly and strongly punctured ; the head has a trans- verse pale mark quite at the vertex ; the thorax is broadly pale at the anterior angles, and this pallid colour extends as an excessively obscure band across the middle of the thorax ; the elytra have a pale humeral mark, and their apical portion is marked with several irregular indistinct, longitudinal pale marks ; these marks are ill defined and probably very variable. Interior of Madagascar. 11G7. 377. Herophydrus spadiceus, n. sp.— Sat angustu.s, convexus, nitidus, piceus, elytris rufo-signalis, crebre fortiter punctatus, antennis pedibusque rufis ; clypeo utriuque marginato, thoracis angulis posterioribus obtusis. Long, i}, lat. 2if m.m. Very similar to H. heros but a good deal smaller, and readily distinguished by the very distinct margin of the clypeus, which however is interrupted in the middle. The red marks on the elytra are smaller and more numerous, the punctuation is not quite so coarse, and the front legs are rather more slender. Madagascar. 62. 378. Hyphydrus guineensis, A.ube, M.C. — Satangustus, convexus, nitidus, piceus, vel piceo-ferrugineus ; dense fortiter punctatus ; antennis pedibusque rufis ; clypeo utrinque marginato, thoracis angulis posterioribus obtusis. Long, il, m.m, lat. 2f m.m. This species is very closely allied to Hydroporus spadiceus, but is rather smaller, is a little more densely punctured, and the elytra are without any distinct markings. Senegal, Arabia, Egypt, Algeria, Corsica. G-3. 394 On Aquatic Carnivorous Coleoptera or DytiscidcB. 379. Hero2:)hydrus obscurus, n. sp. — Ovalis, convexus, fere sine pubescentia, ferrugineus, thorace crebre distincte, elytris crebre fortiter punctatis ; clypei margine medio breviter interrupto. Long, ih, lat. 21 m.ni. Mas, nitidus. Fern., opaca. This species is very close to Heroj:)hydrus oscillator and is just possibly a variety of it, but the upper surface is nearly unicolorous, and the punctuation of the elytra is rather denser. South Africa, (Cape Town). 187. 380. Heroi)hydrus oscillator, n. sp. — Ovalis, convexus, nitidus, sine pubescentia, ferrugineus, prothoracis inarginibus anterioribus et posterioribiis nigricantibus, elytris testaceis siguaturis nigris, antennis pedibusque testaceis ; prothorace crebre distincte, elytris crebre fortiter punctatis ; clypei margine medio breviter interrupto. Long. 4^^, lat. 2f m.m. The markings on the elytra are the suture and a long line near it black, with some shorter black lines outside these, all more or less confluent and confused. The punctures on the elytra are of one size except close to the base where the punctures are more distinct, and a few smaller ones are mixed with them. This species is about intermediate in form between Hjdroporus musicus (No, 300), and Dytiscus parallelogrammus, (No. 416). South Africa. (Atloo Lush, Caflraria). 18G. I. 35.— Genus CCELAMBUS. Ligula on inner face of elytra free and abrupt ; terminal joint of front tarsus not very short in comparison with the third joint, although frequently concealed by the deep fissure of the latter ; humeral area of epipleura limited behind by a well marked line : mesosternal fork not connected with intercoxal process of metaster- num. The numerous species* are usually pale in colour, with dark markings on the * In addition to tliose the characters of which are now given, the following should also be referred to this genus: — Hydroporus Cleopatra;, Peyr. (No. 1351), near No. 390; Syria. — Hydroporus discoideus, Leo. (No. 13G3), near No. 399; North America. — Hydroporus fractilinea, Solsky, (No. 1371); Turkestan. — Hydroponis infacetus, Clk. (No. 1383), near No. -101 ; Mexico. — Hydroporus masculinus Crotch, (No. 1397), near No. 403; North America. — Hydroporus pectoralis, Motsch. (No. 1412); Siberia. — Hydroporus sellatus, Lee. (No. 1429), near No. 401 ; North America. — -Hydroporus tauricns Motsch. (No. 1439), near No. 420; Russia. — Hydroporus unguicularis. Crotch, (No. 1447), near No. 403 ; North America. — Hygrotus impressifons, Motsch. (No. 1458); California. The generic position of the following is doubtful Init probably is near, if not actually in, Coelambtis : Hydroporus inquinatus Boh. (No 138G);Caffraria. On Aquatic Carnivorous Colcoptera or DytiscidcB. 395 wing-cases. They may be arranged in three groups as follows ; (but the distinction between the groups is not very marked, many of the species of the third group approximating to the preceding ones by the labrum being more or less retracted, and the front of the head not very distinctly emarginate). Group. 1. — Labrum much concealed, head rounded in front, and with a more or less distinct raised margin : form usually very short, (the margin on the head is always fine, sometimes very indistinct and obsolete). Species 381 to 3S9. Group. 2. — Head rounded in front, and with a thick, but little elevated margin j labrum moderately concealed, approaching so nearly to the upper- surface of the head, that there is a slight interruption in the middle of the thickened margin. Form short or rather short. Species 390 to 392. Group. 3. — Front of head without margin, and truncate-emarsfinate in the middle in front, labrum little concealed or quite conspicuous ; form oval, more or less elongate. Species 393 to 423. Group 1. 381. Dytiscus insequaJis, Fab., Hydroporus incequalis, M.C. — Brevis, convexus, sat latus, nitidus, sine pubescentia, ferruginous, prothorace basi apiceque nigro, elytris nigris margine externo signaturisque ferrugineis ; capite thoraceque crebre subtiliter, elytris crebre fortiter punctatis ; pectore fortiter, abdomine sat fortiter punctatis. Long. 3, lat. 2 m.m. The markings on the elytra are variable, the sutural portion is always black and the external portion yellowish ; sometimes the black portion is broken by some yellow irregular marks. A variety nearly black in colour from Armenia is in the collection of Wehncke. Abundant in Northern and Middle Europe ; (Algeria, Wehncke). According to Crotch the species has also been found in Illinois, North America. 1 7.5. 382. Hydroporus punctatus. Say, M.C. — Brevis, convexus, latus, sine pubes- centia, ferrugineus, prothorace basi elytrisque obscurioribus, his margine externo dilutiore, capite thoraceque crebre punctatis ; elytris crebre fortiter punctatis ; pectore fortiter, abdomine sat fortiter punctatis. Long. 3, lat. 2 m.m. Closely allied to Dytiscus ina^qualis, (No. 381), but rather different in outline, being broader in the middle and so less parallel in form, with the punctuation of the elytra I'ather dense, and the upper surface without distinct contrasts of colour. United States of North America, (Middle and Western States). 17G. TRANS. BOY. DL'B. SOC, N.S., VOL. II. 3 F 306 On Aquatic Carnivorous Coleoptera or DytiscidoB. 383. Hydroporus hydropicus, Lee, M.C. — Brevis, convexus, sat latus, sine pubescentia, ferrugineus, prothorace basi apiceque elytrisque fuscis, his signaturis vagis pallidioribus ; elytris dense fortiter insequaliter punctatis ; corpore subtus dense fortiterque punctato. Long. 3, lat. 2 m.m. This species is very Uke Dytiscus in^quahs, (No. 381), but the punctuation of the elytra is denser and more uneven, consisting on the basal portion of coarse and fine punctures mixed together ; the species is however readily distinguished by the dilated tarsi of the male. The female I have not seen; according to Crotch it is opaque. California, (San Diego'*. 177. 384. Hydroporus farctus, Lee, M.C. — Subrotundatus, convexus, opacus, sine pubescentia, ferrugineus ; prothorace dense subtilissime punctato ; elytris dense subtiliter reticulatis, punctis adspersis parvis ; pectore dense sat subtiliter rugoso- punctato ; abdomine baud punctato sed alutaceo, opaco. Long. 28, lat. li m.m. I have seen of this species only a typical individual transmitted to me by Leconte, and which has lost its head ; according to Crotch the clypeus is not margined, the species may be easily recognized by its rotund form and peculiar sculpture. The individual I have examined has the front and middle tarsi, short and rather broad, but I am in doubt as to its sex. North America, (^Massachusetts, New Jersey). 179. 385. Coelambus discedens, n. sp. — Ovalis, convexus, nitidus, subtilissime pubescens, brunneo-ferrugineus, prothoracis marginibus elytrisque signaturis vagis pallidioribus ; elytris crebre fortiter punctatis, punctis ad apicem obsoletis ; pectore abdominisque lateribus basi grosse punctatis. Long. 3i, lat. 2 m.m. Antennae slender and elongate. Thorax rather sparingly punctured about the middle, but more closely at the margins. Elytra at the shoulders and base with a large irregular pale mark and another near the extremity ; their punctuation is rather coarse and not dense, at the apex the punctures are nearly Avanting ; the elytra bear a sparing, very fine pubescence. The sternum and coxae and the sides of the abdomen at the base with excessively coarse deep j^unctures. The only individual I have seen, has the three basal joints of the front tarsi elongate, but scarcely or not at all dilated ; I am in doubt as to its sex. I am not sure that it is rightly placed in Ccelambus. China, (Kiu Kiang, found by Mr. Giorge Lewis). 180. On Aquatic Carnivorous Colcoptcra or Di/tistuhr. 397 386. Dytiscus versicolor, Schall. Act. Hal. S13, Hydroporus reticulatus, M.C. — Breviter ovalis, convexus, sat nitidus, sine pubescentia, ferrugineus, elytris vittis interruptis nigris ; creberrime subtilissime punctatus, elytris punctis majoribus adspersis ; processu prosternali antice acute elevato. Long. Si, lat. 2 m.m. The black marks on the elytra of this species consist of interrupted lines, and vary greatly in their extent. I do not see any sexual distinctions. Northern and Middle Europe : ascends, according to Sahlberg, to 65° 55'. 181. 387. Hyphydrus quinquelineatus, Zett., Hydroporus quinquelineatus, M.C. — Breviter ovalis, convexus, nitidus, sine pubescentia, ferrugineus elytris lineis elongatis nigris ; prothorace parce subtiliter punctato, elytris sat crebre et fortiter punctatis, punctis minutis inter majores adspersis ; processu prosternali antice depresso. Long. 3, lat. vix 2 m.m. Europe; Lapland, South Scothxnd, South Ireland, Belgium, Alsace, (Kasan, Wehnckc). Ascends to 68° 30', according to Sahlberg. 182. 388. Hyphydrus decoratus, Gyll., Hydroporus decoratus, M.C. — Brevis, ovalis, latus, convexus, sine pubescentia, nitidus, piceo-ferrugineu«, el3^tris obscurioribus, lateribus maculisque indistincte rufescentibus ; elytris minus crebre sat fortiter punctatis, j^unctiscjue minoribus inter majores adspersis. Long. 2a, lat. li m.m. INIiddlo Europe, (South S\vedcn, England, Germany, France). Not a common species. 184. 389. Hydroporus acaroides, Lee, M.C. — Subrotundatus, subtus convexus, sine pubescentia, ferrugineus, pectore abdomineque jilus minusve infuscatis (vel etiani nigris), elytris nigro-signatis ; elytris dense fere subtiliter punctatis, versus latera plicula elevata abbreviata ; pectore dense fortiter punctato, abdomine baud punctato sed alutaceo, opaco. Long. 2s, lat. if m.m. The colour in this species appears to be variable, especially on the ventral segments ; the species may be readily distinguished amongst its allies by the elytral fold, and the peculiar sculpture of the ventral segments. The tarsi of the male though not broad are distinctly dilated ; the female I am unacquainted with. North America, (Western States). 178. Group 2, 390. Hydroporus musicus, Klug, M.C. — Breviter ovalis, convexus, nitidus, sine pubescentia, ferrugineus, elytris lineis plus minusve interruptis nigris, prothorace crebre evidenter punctato, elytris crebre fortiter fere sequaliter punctatis. Long. 3l, lat. 2\ m.m. 39S On Aquatic Caruicorous CoUoptera or DytisciJte. This species is closely allied to Hypliydrus qiiinquelineatus, (No. 387), but the punctuation of the thorax and elytra is denser, and the punctures on the latter differ little from one another in size. Tlie fovea at the shoulder of the elytra also is less deep. Egypt aud Mount Siiiai. 183. 391. Ca'lanibiis iuterruptus, n. sp. — Breviter ovalis, convexus, nitidus, sine pubescentia ; testaceus, elytris lineis fractis, nigris ; elytris fortiter sub-irregulariter punctatis. Long. 3, lat 2 m.m. Mas, abdomine nigi-icante. This species is very similar to Hyphydrus quinquelineatus (No. 387), but it is j)aler in colour, and the elytra have their black lines more disintegrated, and the punctuation coarser : in colour and the marks of the elytra it greatly resembles Hydroporus musicus, but it is smaller aud narrower, and the punctuation of the elytra is distinctly unequal, the punctures on the basal portion of the wing-cases being a mixture of coarse and fine ones. The front and middle tarsi are slender in each sex, and I can see no sexual difference in the sculpture ; some of the females are not very much smaller in size than H. musicus. Mesopotamia, Dr. Milliiigen. 1137. 392. Coelambus muticus, n. sp.— Ovalis, convexus, pernitidus, sine pubescentia, niger, prothorace medio anguste lateribusque rufescentibus, elytris testaceis lineis latis nigris ; femoribus piceis, tibiis tarsisque rufis, antennis testaceis articulo ultimo fusco; prothorace crebre distincte punctato ; elytris basi subtiliter apice crebrius et fortius punctatis, stria disooidali punctorum; clypei margine cra.sso sed medio interrupto. Long. 4, lat. 2h m.m. This species is about intermediate between Hydroporus musicus (No. 390), and Dytiscus parallelogrammus (No. 416); the marks on the elytra are, the suture and an elongate line near it, and some more irregular marks external to these, black. The breast is impunctate in the middle, coarsely punctured at the sides. The ventral segments are rather closelj' punctured. I see no sexual distinctions. Abyssiiiia, (fouud by Eaffray at Goumdet, Agaos, and Lake Tzana). 185. Group 3. 393. Coelambus chinensis, n. sp. — Oblongo-ovalis, convexiusculus, nitidus, sine pubescentia, pectore abdomineque nigris, capite thorace pedibusque ferrugineis, hoc f;asi nigricaute, elytris obscuris, basi parce apice crebre punctatis, basi seriebus On Aquatic Carnivorous Coleoptera or Dytiscidce. 399 punctoruin impressis obsoletis ; corpore subtus nitido, coxis posterioribus anterius sat crebre profunde punctatis. Long. i\, lat. Ig m.m. Mas, tarsis anterioribus unguiculo externo leviter incrassato et abbreviate. This species approaches extremely near to the sparingly punctured forms of Dytis- cus impresso-punctatus (No. 409), but the under surface is quite polished and shining, whereas it is dulled in all the varieties of D. impresso-punctatus I have seen. The male tarsi are not dilated, but I find that in some European males of D. impresso- punctatus they also are scarcely if at all broader than in the female. The North American Hydroporus disimilis is very closely allied to this species. Nortli China, (Kiu Kiang, found by Mr. Lewis). 206. 394. Hydroporus turbidus, Lee, M.C. — Ovalis, subtus convexus, sine pubescentia, nitidus, pectore abdomineque nigricantibus ; elytris sat crebre et fortiter, intequaliter punctatis; coxis posterioribus punctis magnis et profundis. Long. 3, lat. 1| m.m. This species in size and general appearance approaches Dytiscus insequalis (No. 381), and its allies, and the front tarsi (of the only individual I have seen) are scarcely so developed as in that sjiecies ; the front of the clvpeus is, however, quite without margin, and is distinctly notched in the middle. North America, (United States, Boston'). 394. 395. Hydroporus wardi, Clk., M.C. — Ovalis, sat elongatus, sine pubescentia, sat nitidus, testaceus, pectore abdomineque nigris, elytris vage infuscatis, crebre sat fortiter, sequaliter punctatis, serie punctorum impressa ; coxis posterioribus abdomineque basi utrinque dense punctatis. Long. 4, lat. 2i m.m. ^[as, tarsis anterioribus leviter dilatatis, unguiculo interno leviter incrassato. Mexico. 217. 396. Hyphydrus marklini, GylL, Hydroporus Marlclini, M.C. — Ovalis, leviter convexus, sine pubescentia, nitidus, abdomine pectoreque nigris, prothorace basi apiceque obscurioribus, elytris fusco-testaceis, sutura angustissime nigra, basi sat crebre, apicem versus crebrius et fortius punctatis. Long 3^, lat. 2 m.m. Mas, tarsis anterioribus vix dilatatis, unguiculo interno paulo crassiore. The sexual differences in this species are extremely slight, the punctures on the coxra vary a little, but do not cover so large a part of them as in many of the N. American allies. Lapland, and Kirghiz Steppes. 218. 400 071 Aquatic Carnivoroxos Coleoptera or DijtiscidcE. 397. Coelambus funiatus, n. sp. — Ovalis, angustulus, testaceus, abdomine pectoreque nigricantibus, prothorace basi elytrisque infuscatis, bis dense sequaliter subtiliter punctatis, stria punctorum irapressa distincta ; coxis posterioribus fere crebre punctatis. Long. 3l, lat. 2 tn.m. The only individual I have seen is a female, it is extremely closely allied to Hydroporus lutescens (No. 39S), but is a good deal smaller, the punctures on the coxa are not quite so dose, and the tarsi are much smaller tlian in the individual described of that species. North America, (United States). "216. 398. Hydroporus lutescens, Lee, M.C. — Ovalis, angustulus, elongatus, testaceus, abdomine pectoreque nigricantibus, prothorace basi elytrisque infuscatis, his dense sequaliter subtiliter punctatis, stria punctorum impressa distincta ; coxis posteriori- bus crebre punctatis. Long. 4, lat. 2s m.m. This species is smaller than H. nubilus (No. 403), and more finely and closely punctured : I am not sure as to the sex of the only individual I have seen, the claws of the front tarsi being equal though the tarsi are rather broad ; the shape of the front and middle tarsi is however quite different from what it is in either sex of Hydroporus nubilus. The determination of the name is not certainly cori'ect, as I have seen no typical specimen of this species. Culifoniia, (San Francisco). 215. 399. Hydroporus patruelis, Lee, M.C. — Ovalis, sat elongatus, sine pubescentia, sat nitidus, testaceus, pectore abdomineque nigris, elytris apicem versus vage infus- catis, prothorace basi obscuriore ; elytris minus fortiter, basi minus crebre sub- insequaliter, apice fere dense punctatis ; coxis posterioribus crebre punctatis. Long 4, lat. 2^ m.m. Mas, tarsis anterioribus fortiter dilatatis, unguiculo interno crassiore. Very closely allied to Hydroporus nubilus (No. 403), but less elongate with the male front tarsi rather broader and shorter, and the colour and sculpture not quite similar. According to Crotch, H, discoideus, Lee. (Proc. Ac. Phil. 1855. p. 299), is a male of this species. North America, (United States). 214. 400. H3'droporus suturalis, Lee, M.C. — Ovalis, sine pubescentia, nitidus, testaceus, abdomine pectoreque nigricantibus, prothorace basi et in medio infuscato, elytris On Aquatic Caruivorotis Coleoptera or Dytiscidre. 401 ])allidis plus minusve iufuscatis, sat fortiter fere dense sub-ingequaliter punctatis ; coxis posterioribus punctis densis profundis ; abdominis lateribus ad basin dense confluenter punctatis. Long. 3*, lat. 2 m.m. Tiie only individual I have seen is an immature female. It is extremely close to H. medialis, but is more regularly oval in form, and shows some slight distinctions of colour and sculjiture. North America, (Lake Superior). 213. 401. Hydroporus medialis, Lee, M.C. — Ovalis, sine pubescentia, nitidus, abdomine pectoreque nigris, capite, thorace, antennis pedibusque testaceis, elytris pallidis plaga magna vaga fusca, crebre sat fortiter oequaliter punctatis, stria discoidali punc- torum impressa obsoleta; coxis posterioribus punctis magnis et profundis fere densis, abdominis lateribus ad basin fortiter confluenter punctatis. Long. 3b, lat. la m.m. The sexual difterences are very slight. The male front tarsi are slightly dilated, and the internal claw is a little thicker than the outer. Nortli America, (San Diego, California). 212. 402. Hydroporus ovoideus, Lee, M.C. — Ovalis, sine pubescentia, nitidus, abdomine pectoreque nigris, supra rufescens ; elytris pallidioribus sutura angustissime nigra, sat crebre et fortiter fere sequaliter punctatis ; corpore subtus nitido, coxis posteri- oribus sat crebre punctatis. Long. 32 lat. 2 m.m. I have seen only a single specimen of this species which is closely allied to- Hyphydrus marklini (No. 396), but is a little broader and has the punctuation of the elytra and thorax more sparing : the two may, however, perhaps prove to be one species. North America, (Lake Superior). 210. 403. Hydroporus nubilus, Lee, M.C. — Ovalis, angustulus, elongatus, fere sine pubescentia, sat nitidus, testaceus, pectore abdomineque nigris ; elytris siguaturis coalescentibus plus minusve distinctis fuscis, crebre aequaliter fere subtiliter punc- tatis, coxis posterioribus crebre punctatis. Long. 4g, lat. 22 m.m. The male has the front and middle tarsi distinctly dilated, and the internal claw on the front ones thickened. The female is not quite so shining as the male, and has the middle tarsi elongate and much compressed. North America, (Massachusetts, PhUadelpliia, Texas, Colorado). 208. 404. Coelambus infuscatus, n. sp. — Oblongo-ovalis, fere sine pubescentia, testaceus, abdomine pectoreque nigris, elytris signaturis magnis coalescentibus fuscis, dense. 402 Oil Aquatic Carnivorous Coleopteia or Di/tiacidie. sequaliter subtillter punctatis, serie punctorum impressa minus distincta ; coxis postcrioribus externe minus crebre punctatis. Long. 5, lat 2i m.m. This species is readil}^ distinguished from Hydroj^orus nubilus (No. 403), by its larger size, and more finely and densely punctured elytra. I have seen only two individuals, both of which are females, one is shining, the other dull ; the front tarsi are less compressed and are broader than in the corresponding sex of Hydroporus nubilus. North America, (Nevada). 209. 405. Hydroporus fraternus, Lee, M.C. — Ovalis, sine pubescentia, nitidus, ferruginous, abdomine pectoreque nigris, elytris signaturis fuscis, fortiter crebre ffiqualiter punctatis, punctis apicem versus fere densis ; coxis posterioribus, abdomineque ad basin punctis magnis profundis densis. Long. Sh, lat. 28 m.m. Mas, tarsis anterioribus fortiter, intermediis sat dilatatis, illis unguiculo interno paulo crassiore. I have seen only a single male of this species. North America, (California). 219. 406. Hydroporus polonicus, Aube, M.C. — Ovalis, fere sine pubescentia, sat nitidus, testaceus, abdomine pectoreque vel nigris vel testacies ; elytris creberrime subtiliter punctatis, punctis ad basin insequalibus ; prothorace elytris evidenter angustiore, lateribus leviter obliquis. Long. 4^, lat. 2? m.m. 31 as, tarsis anterioribus et intermediis valde dilatatis, anterioribus unguiculis crassis, elongatis, subrectis, externo paulo breviore ; abdomine coxisque posterioribus nigris. Fern., abdomine coxisque posterioribus testaceis. According to Aub^ there is a female form of this species which is quite dull and more finely punctured. Europe, (Poland, Southern Russia). 220. 407. Ccelambus sahlbergi, n. nom. — 3. Ovalis, fere sine pubescentia, sat nitidus, testaceuS; abdomine pectoreque nigris ; elj'tris creberrime subtiliter punctatis, punctis ad basin insequalibus, prothorace elytris evidenter angustiore, lateribus leviter obliquis ; coxis posterioribus parce sat fortiter punctatis. Long. 4j, lat. vix 2^ m.m. Has, tarsis anterioribus et intermediis articulis 1 et 2 leviter dilatatis ; anterioribus unguiculis crassis, elongatis, subrectis, externo paulo breviore. I have seen but one individual which scarcely difters from the male of H. polonicus, except by the little dilated tarsi. On Aquatic Carnivorous Coleoptera or Dyiiscidce. 403 This species was described by Sahlberg as Coelambus unguicularis, but as Crotch had recently described another species under that name, I have been obUged to find a new one for Sahlberg's species. Siberia, (Jenisei, July, 187G, Dr. J. SahU.erg). 458. 408. Hydroporus dissiinilis, Har., M.C. — Ovalis, convexiusculus, nitidus, sine pubescentia, ferrugineus, abdomine pectoreque nigris ; elytris sat crebre insequahter punctatis; corpore subtus nitido, coxis posteriori bus fortiter punctatis. Long. 4, lat. 2| m.ni. I have seen but a single female of this species which is very close to the more sparingly punctured forms of Dytiscus impresso-punctatus, (No. 409), but is very shining beneath. North America, (Illinois, Lake Superior, New York). 207. 409. Dytiscus impresso-punctatus, Schall., Hijdroporus picipes, M.C. — Oblongo- ovalis, sat angustus, convexiusculus, glabriculus, pectore abdomineque nigris, supra obscure ferrugineus, vertice utrinque, prothorace basi elyfcrisque lineis indistinctis nigricantibus ; elytris basi fortiter profunde infequaliter punctatis, stria suturali aliisque duabus externis punctorum ad basin impressis, apicem versus dense fere gequaliter punctatis ; coxis posterioribus crebre, fortiter profunde punctatis. Long. 5, lat. 2 1 m.m. Mas, tarsis anterioribus et intermediis bene dilatatis, anterioribus unguiculo interno leviter incrassato. Fern., (a) ut in mare punctata et nitida. (6) omnino opaca, elytris dense gequaliter magis subtiliter punctatis, seriebus punctorum impressis obsoletis. This species varies greatly in size, colour, and in the punctuation of the upper surface ; in some of the varieties the impressed series of punctures are scarcely to be distino-uished. H. decemlineatus, Mann, and H. picatus, Kirb. , are North American varieties. Europe and Asia Minor, Siberia, Sitka, and United States of North America. 205. 410. Coelambus elevatus, n. sp. — Ovalis, convexus, breviusculus, nitidus, testaceo- ferrugineus, elytris lineis elongatis, alternis ad basin abbreviatis, fuscis; coxis posterioribus externe parce punctatis. Long. 4, lat 2i m.m. This species is very similar to H. saginatus, Schaum, (No. 412), but is much shorter, and the under surface is pale : the only individual I have seen is a female, the wing-cases are shining at the base, and the punctuation there consists of not TBANS. HOT. PUB. SOC, U.S., VOL. II. 3 G 404 On Aquatic Carnivorous Coleojjtera or Diitisciia;. very close coarse punctures, and finer ones mixed with them, behind the middle the punctuation is closer, and the punctures of one size, and on this part a fine short pubescence may be detected ; at the base there may be seen indistinctly two irregular stria?, simi'ar to those which are much more distinct in Dytiscus impresso- punctatus, (No. 409). Egyi^t, (Dr. Millingen). 113G. 411. Hydroporus corpulentus,Schaum, M.C. — " Ovalis,convexus, parce punctatus, supra testaceus, infra niger, fronte juxta oculos, prothoracisque puncto medio nigro-fuscis, elytris prgeter suturam lineis quatuor, secunda quartaque basin attingente, lineoli.sque externis tenuibus nigris. Long. "\, lin." (Schaum). Coxis posterioi'ibus externe parce punctatis. Long. 5, lat. 2i- m.ui. I have seen only a single female of this species, it is of very much broader form than D. parallelogrammus (No. 416); the punctuation of the wing-cases is rather coarse, and not dense, the intermixed fine punctures are indistinct. Schaum says nothing of the male characters. It appears to be very like H. saginatus, but to be very much broader. Europe, (Crimea). 1135. 412. Hydroporus saginatus, Schaum, M.C. — " Ovalis, convexus, punctatus, nitidulu s, supra testaceo-ferrugineus, infra niger, capite postice obscuriore, prothoracis lateribus obliquis vix rotundatis, puncto medio fusco, elyti'is prreter suturam lineis quatuor, secunda, nonnunquam etiam quarta basin attingente lineolisque duabus externis nigris. Long. 21 lin." (Coxis posterioribus externe parce minus fortiter punctatis). Long, ih, lat. 2| m.m). J/as, " valde nitidulus, femina minus nitida crebrius et subtilius punctata," (ex Schaum). I have seen only one individual of this species. It is shorter than Dytiscus paral- lelogrammus (Xo. 416), with the punctuation of the elytra consisting of moderately large not dense punctures, which at the base are more distant and have on the interstices not very distinct finer punctures : this individual appears to be a female, and differs from D. parallelogrammus, independently of its size and i^unctuation, by the more ^jrolonged black lines on the elytra. Greece, (Nauplia, Kiesenwetter). Asia IMinor? 204. 4 1 3. Coelambus inscriptus, n. sp. — Ovalis, sat angustus, sine pubescentia, nitidus, testaceus, abdoraine pectore, elytrorum sutura, linea postice dilatata, maculisque duabus nigris ; elytris sat crebre et fortiter punctatis ; coxis posterioribus parce fortiter punctatis. Lorg. 3l, lat. 2 m.m. On Aquatic Carnivorous Coleoptera or Dytiscidie. 405 Mas, tarsis anterioribus sat latis, unguiculo interne sat abbreviato et incrassato. This pretty little species is readily distinguished from its allies by the extreme minuteness of the fovea on the middle of the thorax, and by the markings of the elytra. The elytra are pale yellow, with the suture narrowly black, and with a black line near the suture which reaches neither to the base nor the ajiex, and is thickened at its termination, while outside this line are two black spots. I have seen only two males. Persia, MesoiJOtamia, (Dr. 0. Millingeu). 203. 414. Coelambus orthogrammus, n. sp. — Oblongo-ovalis, sat elongatus, sine pubescentia, nitidus, testaceus, abdomine, pectore elytrisque lineis elongatis nigris ; prothorace medio foveola minuta ; elytris basi obsolete, apicem versus crebre subtiliter punctatis ; corpore subtus fere opaco, coxis posterioribus parce subtiliter punctatis. Long. 41, lat. 21 m.m. This species is very much smaller than D. parallelogrammus (No. 416), and is more finely and sparingly punctured ; it resembles Hydroporus lernteus extremely but is broader in proportion to its length, and more finely and sparingly punctured. The only individual I have seen is a female. Persia. 202. 415. Hydroporus lernieus, Schaum, M.C. — Oblongo-ovalis, elongatus, angustulus, sine pubescentia, nitidus, testaceus, abdomine pectoreque, thoracis macula media elytrisque lineis elongatis nigris ; prothorace medio foveola minuta ; elytris pone basin dense, basi insequaliter (punctis majoribus parcis), punctatis ; corpore subtus subopaco, coxis posterioribus sat crebre punctatis. Long. 41, lat. 21 m.m. Mas, tarsis anterioribus et intermediis sat dilatatis, anterioribus unguiculo interne minuto, crasso, valde curvato. Very closely allied to Dytiscus parallelogrammus (No. 416), but smaller and narrower, and with the elytra at the base only bearing a few large punctures. According to Schaum, the female is shining like the male. Greece, Egypt, Syria. 201. 416. Dytiscus parallelogrammus, Ahrens, Hydroporus parallelogrammus, M.C. — Oblongo-ovalis, elongatus, sine pubescentia, testaceus, abdomine jiectoreque, thoracis macula media elytrisque lineis elongatis nigris ; prothorace medio foveola parva ; elytris dense punctatis, punctatura basi intequali, punctis majoribus parcis ; corpore subtus fere opaco, coxis posterioribus sat crebre sed sub-obsolete punctatis. Long. 4?, lat. 21 m.m. 3 6a 40G On Aquatic Cnrnivorons Cohoptcra or Di/titscidui. Mas, supra nitidus, tarsis anterioribus et intermediis dilatatis, anterioribus unofuiculo interno crassiore et masfis curvato. Fern, (a) fere ut in mare punctata et nitida. (h) omnino opaca, obsolete punctata. The two forms of the female seem to have a different geographical distribution. In the northern part of its area it is cliiefl}^ if not solely, the dull form that is found, while in the south this form seems to be absent. In Central Europe both forms are found. Europe ; Corsica, North Africa. In brackish aud fresh waters, widely distributed, Init absent from tlie north of Europe. 200. 417. Hydroporus novemlineatus, Steph., M.C. — Ovalis, sat elongatus, sine pubes- centia, testaceus, thoracis macula media, elytroruna lineis quatuor elongatis, pectore abdomineque nigris ; elytris dense subtiliter sed distincte punctatis ; prothorace medio foveola minuta ; cosis posterioribus crebi-e sat subtiliter punctatis. Long. 4, lat. 2 m.m. il/a.% supra sat nitidus, tarsis anterioribus et intermediis fortiter dilatatis, anterioribus unguiculo interno breviore et crassiore, magis curvato, apice acuminato. Fern., (a) supra omnino opaca. (h) ut in mare punctata et nitida. In Scotland I have found only the dull form of the female; but of two specimens of that sex sent me from Karelia by Dr. Sahlberg, one is the dull form, the other the shining one. Nortliern Eiu'ope. (Found in hikes in Scothxnd and Lapland). 109. 418. Hydroporus lautus, Schaum, M.C. — "Ovalis, oonvexiusculus, supra testaceus, capite postice prothoracisque puncto medio nigris, elytris j^arce subtiliter punctulatis, lineis quatuor nee basin nee apicem attingentibus nigris : pectore utrinque sparsim sat fortiter punctate. Long. If, lin." 3'- m.m. 3Ias, nitidus, tarsis anterioribus et intermediis fortiter dilatatis. Fern., " opaca subtilius punctata." (ex Schaum.) The claws on the front foot of the male are very fine, but the anterior one is stouter than, aud twice as long as the minute hinder one. The comparatively short broad form of the species gives it some resemblance to Dytiscus confluens, (No. 423). Europe : Germany. (This species was found in brackish water near Halle, about thii-ty years ago ; a single pair is all I have seen of it). 198. 419. Hydroporus enneagrammus, Ahrens, Hydroporus nigro-linentus M.C. — Oblongo-ovalis sat convexus, sine pubescentia, testaceixs, pectore abdomineque On Aquatic Carnivorous Colcoptera or Dz/titicida'. 407 nigris; elytris lineis quatuor integris nigris ; omnium subtilissime densissimeque punctatus fere Isevis, (corpore subtus impunctato). Long. 3->, lat. vix 2 m.m. Mas, nitidulus, tarsis anterioribus leviter dilatatis. Fern., opaca. Var. Lineis nigris elytrorum alternis abbreviatis. Europe. (Transylvania, South Eussia.) The variety is from the Caucasus and Persia. 197. 420. Hydroporus flaviventris, Motsch., M.C. — Ovalis, minus convexus, sine pubescentia, nitidulus, supra capite tboraceque rufo-testaceis, elytris pallide testaceis lineis abbreviatis nigris ; capite evidenter punctato, thorace fere impunctato, elytris omnium subtilissime, densissime vi.x; visibiliter punctulatis, corpore subtus fere impunctato. Long. 3f, lat. 2| m.m. il/os, pectore abdomineque nigris, hoc apice rufescente. Fern., subtus rufo-testacea. This species is very similar to Hydroporus pallidulus, Aube (No. 422), but is rather more elongate, and is readily distinguished by its more obsolete sculpture ; the punctuation on the wing cases is so fine that it is not very easy to detect it, and the punctures of the undersurface are also obsolete. Western Asia, (Soiigoria, Indersk). 19G. 421. Hydroporus caspius, Wehncke, Deutsch. Ent. Zeit. 1873, p. 234. — Ovalis, supra minus convexus, sine pubescentia, nitidulus, niger, supra cum antennis pedibus- que testacei.s, vertice lineisque elytrorum nigris ; elytris crebre obsoletissime punctatis, versus suturam punctis sparsis sat distinctis, serie discoidali obsoleta ; coxis posterioribus sparsim obsolete punctatis. Long. Ss, lat. li m.m. This species (of which I have seen but a single example) is even more elongate than II. pallidulus (No. 422), and is readily distinguished from it and Dytiscus confluens (No. 423), by the obsolete punctuation of the hind coxiB, as well as by the black colour on the head. Europe, (Astrakan). 195. 422. Hydroporus pallidulus, Aube, M.C. — Ovatus, crassus, sat convexus, supra pallido-testaceus, infra (ex parte) niger ; elytris quatuor lineis abbreviatis prater suturam utrinque nigro-ornatis, subtilius punctulatis ; coxis posterioribus crebre fortiter punctatis. Long. 3h, lat. 2 m.m. Mas, pectore abdomineque nigris. Fern., pectore nigro, abdomine pallido. Very similar to Dytiscus confluens (No. 423), but narrower and less convex. 4JS On Aquatic Carnivorous Coleoptera or Dytiscithe. I have seen only a single pair of this species ; the male has the breast and hind body black beneath, while in the female the ventral segments are pale red ; the sides of the metasternum, and the hind coxte except their posterior portion, are rather coarsely punctured. The punctuation of its elytra consists of numerous extremely fine punctures, evenly distributed as in Dytiscus confluens, but the larger punctures which are sparingly but distinctly to be seen in the conunon species, are reduced to three or four punctures at the base and along the suture in Hydroporus pallidulus ; it possesses however a distinct discoidal line of fine impressed punctures on each wing case. Aube says the female is opaque but in the individual before me the elytra of that sex are about as shining as in the male, though just perceptibly more finely punctured ; it is probable therefore that there are two forms of the female in this species. Southern Europe, (Sicily and Andalusia) and Nortli Africa, (Algeria, Bune, ^Morocco). 194. 423. Dytiscus confluens, Fab., Hydroporus conjluens, 31. C. — Ovalis, brevis, subtus sat convexus, sine pubescentia, sat nitidus, subtus niger, supra testaceus, elytris pallidis, sutura lineisque abbreviatis nigris, antennis pedibusque testaceis ; elytris punctis parcis sat magnis, aliisque densis minimis ; coxis posterioribus crebre fortiter punctatis, metasterno medio nitido fere impunctato. Long. 31, lat. 2 m.m. The external difference between the sexes seems to be extremelv slight. Middle and Southern Europe, North Africa, and Canary Isles. 193. I. 3G.— Genus CIIOSTONECTES. The rido-e on the inner face of the wing-case shows no lignla near the apex ; the posterior portion of the epipleura is rather broad, and the genicular area is not limited by a raised line ; the hind tibia shows on its infero-external face only the serial punctures ; the posterior femur is slender and its outer angle rounded. The mesosternal fork is not connected with the intercoxal jirocess of the metasternum. The four species * are found in Australia and Tasmania ; they are broad, robust, compact insects. 424. Chostonectes sharpi, (Wehncke), n. sp. — Ovalis, sat latus et convexus, posterius subacuminatus, opacus, evidenter pubescens, fusco-nigei-, capite, thorace * In addition to these four species another but imperfectly known to me should be referred to Chostonectes, viz., Hyphydrus johnsonii, Clk. (No. 1149 huj. op.), near No. 425; Australia. The position of the fvjllowint' is doubtful, but may be iii Chostonectes, Hydroporus bakewelli, Clk. (No. 1343); Australia. On Aquatic Carnivorous Coleoptera or DytiscidcB. 409 transversim in medio, elytrorum signaturis, f.nteanis pedibusque rufescentibus ; clvpeo antice rotundato, sed vix marginato, cajiite dense strigoso-punctato ; thorace elytrisque crebre fortiter punctatis ; corpore sultus fortiter punctato. Long. 3 J, lat. 2 m.m. The marks on the elytra consist of a broad irregular sub-basal fascia which does n.)t quite reach the suture, and some irregular marks towards the extremity which vary in their extent. The four individuals I have examined all have the tarsi simple. Australia, (New South Wales, Sidney). 190. 425. Chostonectes latus, n. sp. — Ovalis, latiusculiis, sat convexus, posterius sub- acuminatus, subopacus, evidenter pubescens, nigricans, eapite, thoracis lateribus, elytrorum signaturis basalibus et externis, antennis pedibusque feiTugineis ; clypeo antice rotundato sed vix marginato, eapite crebre punctato ; thorace elytrisque crebre sat fortiter punctatis ; corpore subtus fortiter punctato. Long. 4t, lat. 2 1 m.m. Mas, tarsis anterioi'ibus et intermediis articulis sat fortiter dilatatis. Fern., tarsis anterioribus et intermediis latiusculis, articulis basalibus baud dilatatis. Australia, (Victoria, Mens Miicedon). 191. 426. Hydroporus nebulosus, MacLeay, Tr. N.S.W. 1871, p. 123. — Late ovali-s, brevis, sat convexus, opacus, evidenter pubescens, ferrugineus, elytris ferrugineo fuscoque obscure variegatis ; clypeo rotundato, sat distincte marginato, eapite subtiliter striguloso ; elytris crebre fortiter minus profunde punctatis, corpore subtus fortiter punctato. Long. 31^, lat. 2|-, m.m. The three individuals I have seen of this species have the tarsi slender, and are perhaps females. Australia, (Sidney). 189. 427. Hydroporus gigas, Boh., M.C. — Ovalis, sat latus et convexus, subnitidus, evidenter pubescens, pectore abdomino, antennis pedibusque rufis, supra nigricans, eapite anterius et in medio, prothorace lateribus, elytris fascia interrupta basali maculisque externis ferrugineis ; corpore creberrime sat fortiter fere cequaliter punctato ; clypeo anterius subrotundato, indistincte incrassato, sed baud marginato, Long. 61, lat. 3|, m.m. Mas, tarsis anterioribus et intermediis bene dilatatis parallelis, unguiculis (prEesertim anterioribus) magis elongatis. Australia and Tasmania, (Clarence River, INIelbourne, Sidney). 192. 410 On Aquatic Carnivorous Coleoptera or Dytiscidce. I. 37.— Genus ANTIPORUS. Posterior portion of epipleura comparatively broad ; hind tibia punctured on the inf'ero-external aspect; the true fourth joint of front tarsus is scarcely visible. The mesosternal fork is not connected with the intercoxal process of the metasternum. The eight species * are found in Australia, Tasmania and New Zealand. 428. Hydroporus femoralis, Boh., M.C. — Ovalis, latiusculus, brevissime pubescens, dense fequaliter, sat subtiliter punctatus, subopacus, niger, prothorace utrinque, pedibus antennisque rufo-testaceis, his versus apicem infuscatis, elytris versus latera signaturis obsolete rufescentibus ; corpora subtus densissime fequaliter 2)unctulato, opaco. Long. 5, lat. 2f, m.m. In the male the front and middle tarsi are broader than in the female, and the front ones bear only one claw, which is moderately long and bears a tooth at its extreme base ; the middle tibia3 are slightly curved ; the hind femora have a large angular dilatation near the apex, on the outer side the sinus of this tooth is not angulated. In the female the elytra are sinuate-truncate at the apex. Although Boheman describes his H. femoralis as having the abdomen yellow, I believe it will prove to be a vai-iety of this species. Tasmania, Australia. 422. 429. Hydroporus interrogationis, Clk,, M.C. — Ovalis, brevissime pubescens, dense sequaliter sat subtiliter punctatus, subopacus, niger, antennis pedibusque testaceis, supra fusgo-niger, signaturis magnis testaceis ornatus ; corpore subtus densissime fequaliter punctulato, opaco. Long. 43, lat. 2^ m.m. This species is closely allied to Hydroporus femoralis (No. 428), but is narrower, and is more oi'namented with yellow, and the male characters show some slight differences ; the unguiculus of the anterior tarsus, is more thickened in the middle ; and the large dilatation of the hind femora takes the form of a tooth in consequence of its sinus externally being angulated. The female has the front tarsi more slender. All these characters vary somewhat in the small series of the two forms before me, and I fancy both may prove to be but one species. Australia. 423. 430. Hydroporus wakefieldi. Sharp, Ent. Mo. Mag. XIII, p. 20. — Oblongo- ovalis, vix pubescens, dense sequaliter sat fortiter punctatus, subopacus, niger, supra * In addition to them, the following should be refen-ed to the genus : Hydroporus gravidus, Clk. (No. 1374 huj. op.) near No. 434 ; Australia. On Aquatic Carnivorous Coleoptera or DijtisciJcii. 411 plus minusve testaceo-ornatus, antennis pedibusque rufo-testaceis, illis versus apiceni plus minusve infuscatis, corpore subtus densissime sequaliter punctato, subopaco. Long. i\, lat. vix 2i m.m. The male has the front and middle tarsi rather broader than in the female ; the front ones with a single uiit>'uiculus, which bears a tooth at the extreme base, the middle tibise are a little curved, and the hind femora have a large triangular dila- tation near the extremity. The species though extremely similar to Hydroporus inter rogationis can scarcely be considered a variety of it, as the sculpture is very distinctly coarser. New Zealand, (Canterbury). 424, 431. Hydroporus duplex, Sharp, Ent. Mo. Mag. XIII, p. 21. — Oblongo-ovalis, vix pubescens, dense requaliter sat fortiter punctatus, subopacus, niger, vel fuscus, antennis, pedibus protlioracisque lateribus testaceis, elytris obsolete testaceo-ornatis, corpore subtus densissime cequaliter punctato, subopaco. Long. 4f, lat. 2i- m.m. This species is extremely close to Hydrojiorus wakefieldi, but is a little larger, and more indistinctly ornamented with yellow, and the thorax is a little more rounded at the sides ; the male characters are the same as in H. wakefieldi, and it is possible that specimens from other localities may prove the two not to be distinct. New Zealand, (Auckland). 425. 432. Hydroporus uncifer, n. sp. — Oblongo-ovalis, brevissime pubescens, dense sequaliter sat subtiliter punctatus, subopacus, niger, supra testaceo fuscoque variegatus, antennis pedibusque testaceis ; prothorace elytris angustiore ; corpore subtus densissime sequaliter punctulato, fere opaco. Long. 5, lat. 2i m.m. The male is larger than the female, and has the front and middle tarsi broadly dilated, the front ones bear each a single claw, which is abruptly curved and has a tooth at the extreme base ; the middle tibice arc a little curved ; and the hind femora have near the extremity a large angular dilatation the apex of which is acute and often a little hooked. Though the species is in most respects allied to H. wakefieldi, yet it differs by the prostei'nal process being broader and much less compressed towards the extremity. New Zealand, (Wellington and Dunedin). 42G. 433. Hydroporus gilbertii, Clk., M.C. — Oblongo-ovalis, brevissime pubescens, densissime subtiliter punctatus, opacus, ferrugineo-testaceus, elyti'is minus distincte nigro-lineatis, thorace basi utrinque rugositatibus distinctis ; corpore subtus omnium densissime subtilissimeque punctato, opaco. Long. 5l, lat. 2! m.m. TRANS. ROT. DUB. SOC, N.S., VOL. II. 3 U 4!2 On Aquatic Cariticoivus Culeoptera or VytiscidoB. In the male the front and middle tarsi are rather elongate and moderately broad, the front ones furnished with a single abruptly curved claw, which bears a tooth at the base ; the hind femora are dilated towards the extremity and furnished with a sharp hooked tooth. In the female the front tarsi are very slender and com- })ressed, the second and third joints showing a well marked constriction, or neck, at the base. Australia. 427. ' . 434, Hydroporus blakei, Clk,, M.C. — Oblongo-ovalis, latiusculus, brevissirao pubescens, densius subtiliter punctatus, opacus, ferruginous ; elytris fuscis, signa- turis externis lineaque suturali vage ferrugineis ; prothorace basi sequali ; elytris apicibus subprolongatis, sinuatim truncatis ; corpore subtus densius punctato, opaco, coxis posterioribus interne fortius punctatis. Long. 4s, lat. 2-J m.m. In the male the front and middle tarsi are a good deal dilated, the third joint is divided nearly to the base so that the lobes are elongate and slender ; on the front feet there is a single unguiculu3, which is short, thick, and sinuate, and has a sharp tooth at the base ; the intermediate tibias are curved and incrassate, and bear a large angular projection on the middle externally. Austi-alia and Tasmania. 428. 435. AntijDorus curtulus, n. sp. — Latus, brevis, omnium brevissime pubescens, densissime subtiliter punctatus, opacus, testaceus, prothorace anterius et posterius infuscato, elytris nigro-fuscis, sutura, margine externo signaturisque versus latera testaceis ; elytris apicibus sub-prolongatis, emarginato-truncatis ; corpore subtus densissime subtilis.sinie punctato, opaco. Long. 3s, lat. vix 2 m.m. I have seen only females, which are very similar to that sex of Hydroporus blakei, but the species is readily distinguished by the smaller size and shorter and broader form, the distinct markings of the elytra, and the rather finer and denser punctuation of the under surface. It is possible that this species may prove to be the Hydroporus bakewelli, Clk. Australia, (Sidney). 429. I. 3 S.— Genus XECTEROSOMA. The true fourth joint of the front tarsus is conspicuously exposed at the base of the terminal joint. This character is more conspicuous in the males than in the females, and is frequently accompanied by a great elongation of the terminal On Aquatic Carnivorous Coleuptera or Dijtiscidw. 413 joint. The mesosteriuil fork is not connected with the intercoxal process of the metasternum. The species ' are Australian and Tasmanian. It should be noted that the Australian and Tasmanian genus Sternopiscus likewise has the front tarsi evidently five-jointed, but it has a very different structure of the mesosternum, (see p. 384). 4oG. Hydroporus penicillatus, Clk., M.C. — (Species pervariabilis) — Brevis^sime pubescens, supra et infra densissirae subtiliter punctatus, subopacus ; elytris ssppius longitudinaliter carinatis, sed interdum omnino requalibus ; tarsorum anticorum articulo tertio brevi. Lono-. 4, lat. 24 m.m. The male is usually rather larger than the female, and has the front and middle tarsi moderately dilated, the front tibiae are slender, and have a slight but distinct notch in the middle of the inner edge, the middle tibiaa are a little curved. The species is excessively variable, in colour, sculpture, and even in outline. Individuals from Tasmania ai'e black, with the head yellow, and the sides of the thorax and the outer margins of the elytra also of that colour, the legs and antennae are also yellow with the outer portion of the latter infuscate : these dark individuals have an acutely elevated carina on the middle of the elytra. Individuals from West Australia present the other extreme ; they are entirely pale yellow, with the base of the thorax and some lines on the elytra black, and there is no trace in some of these individuals of any unevenness on the elytra. Intermediate specimens in all these points are found, the variations being ajtparently rather constant in each locality. The male characters do not vary much, but the Tasmanian individuals of that sex have the front tarsi broader than those from Swan River. The female always has the front tarsi rather broad ; each of the three basal joints being as broad as, or rather broader than long. Tasmania, and Australia. 430. 437. Hydroporus darwinii, Bab., M.C. — Ovalis, omnium densissime brevissimeque pubescens, densissimeque punctatus, opacus, sordide rufus, prothorace basi elytrisque signaturis confluentibus nigris ; corpore subtus densissime punctato, omnino opaco : tarsorum anticorum articulo tertio elongato, basi tenui. Long. 41, lat. 2| m.m. The male has the anterior and middle tarsi moderately broad ; the front tibiae are moderately broad, and have a deep notch on the middle of their inner edge, * In addition to those of wliich the characters are now given, tlie following also belong to the genus : Necterosoma flavicolle, Macl. (No. 1496), ? = No. 441; Australia. — Necterosoma vittipenne, Macl. (Nc. 1497),!= No. 43G; Australia. 3 H» 414 On Aquatic Carnivorous Colcoptera or DytiscidcB. the middle tibiae are greatly curved. The female has the second and third joints of the front tarsi each longer than broad, and slender at the base. The species much resembles those oval varieties of Hydroporus penicillatus in which the elytra are quite even, but is readily distinguished by the diflerences in the front tarsi, and the more developed sexual characters. The female is broader behind the middle, and is subsinuate at the sides before the extremity. Australia, (King George's Sound). 431. 438. Necterosoma schmeltzi, (Wehncke), n. sp. — Ovalis, baud latus, brevissime pubescens, densissime punctatus, fere opacus, niger, pedibus antennisque rufes- centibus, capite anterius, prothorace lateribus elytrisque signaturis transversis undulatis testaceis ; capite angustulo ; prothorace icedio baud omnino subtiliter punctato ; corpore subtus densissime punctulato, fere opaco. Long 4i, lat. 2i ni.m. The male has the front tarsi moderately, the middle ones broadly dilated, the front tibia3 are only moderately stout, and have a moderately deep notch in the middle of the inner edge, the middle tibite are a little curved. In the female the front tarsi are slender with the second and third joints elongate. The species is readily distinguished by the colour and markings. Australia, (Sidney). 432. 439. Hydroporus undecimlineatus, Bab., M.C — Ovalis, brevissime pubescens, densissime punctatus, opacus, rufus, elytris lineis maculisque interjectis nigris ; corpore subtus densissime punctato, opaco. Long. 4, lat. 21 m.m. In the male the front and middle tarsi are much dilated, but the third joint of the front ones is longer than broad, the front tibiae are very thick, and have a large excision in the middle of the inner edge, the middle tibiae are a little curved. In the female the front tarsi are elongate and slender, the second and third joints having a peculiarly elongate and slender basal portion. The species is very close to Hydroporus dispar, and is just intermediate between it and H. wollastoni ; but is rufous beneath, and has tbe marks of the elytra more separate than in H. dispar, the front tibiai are not so extremely Isroad in the male and have the notch less ; and in the female the second and third joints of the front tarsi are much more constricted on their basal portion, than in H. disjmr female. The male is readily distinguished from that sex of H. wollastoni, by the thick front tibiae with very large excavation ; the female appears to differ from the corresponding sex of H. wollastoni only by the rather more coarsely punctured upper surface. Australia. (Clyde River). 433. Hydroporus undecimlineatus, Bab., was stated bj- its describer to have been found in South America, but I i'eel no doubt that this locality was given in error. On Aquatic Carnivorous Coleoptera or Dytiscidce. 415 440. Hydroporus dispar, Germ., M.C. — Ovalis, brevissime pubescens, densissime punctatus, opacus, nigricans, antennis, pedibus, capite, thorace elytrisque testaceis, thorace medio latius infuscato, elytris lineis undique confluentibus obscuratis ; corpore subtus densissime punctato. Long. 4|, lat. 2? m.m. In the male the front and middle tarsi are broad, and the front tibiae are extremely thick, and have a very large excision in the middle inwardly : the middle tibise are a little curved. The front tarsi of the female are elongate and slender. Australia, (Adelaide). 434. 441. Hydroporus wollastoni, Clk., M.C. — Ovalis, brevissime pubescens, densis sime punctatus, subopacus, ferrugineo-testaceus, antennis, pedibus, capite thorace- que testaceis, elytris lineis plurimis nigris, ad latera et inter lineas primam et secundam maculis interjectis ; corpore subtus densissime punctato, opaco ; tarsis anterioribus et intermediis elongatis. Long. 4t, lat. 2l m.m. In the male the front and middle tarsi are broad ; the front tibias are moderately broad, but their lower part is not thick, so that the notch on the inner edge appears to make only a shallow excision : the middle tibite are a little cui'ved. In the female the thorax forms a more continuous line with the elytra than it does in the male, the surface is duller, and the front and middle tarsi are slender. Though the species varies a good deal, I have not quite been able to connect H. undecimlineatus, (No. 439), with it. Australia. 435. 442. Necterosoma regulare, n. sp. — Ovalis, brevior, convexus, omnium brevissime pubescens, subopacas, densissime, sat subtiliter ruguloso-punctatus, testaceus, pectore abdomineque fuscis, thorace anterius et posterius elytrisque lineis latis nigris ; corpore subtus densissime punctato, coxis fortiter rugulosis ; prothorace lateribus ante medium obsoletissime angulatis. Long. 31, lat. 2s m.m. Ths male at first sight differs but little from the female ; it has however the front and middle tarsi slightly broader, and the front tibise have a sliglit emargination near the extremity, the middle tibix' also have their lower portion somewhat excised. Australia, (Port DenLson, and North West Australia). 436. 443. Necterosoma arcuatum, n. sp. — Ovalis, brevior, sat convexus vix pubescens, opacus, densissime sat subtiliter ruguloso-punctatus, ferrugineus, prothorace anterius et posterius nigro, elytris lineis nigris ; corpore subtus densissime punctato, coxis sat fortiter rugulosis. Long. 3f, lat. 2i m.m. 416 On Aquatic Carnivorous Coleoptera or Dyti.scidce. In the male the front and middle tarsi are a good deal broader than they are in the female, and the front tibiae have a slight excision on the inner edge below the middle ; the middle tibiae also have their lower portion excised inwardly. The species is very closely allied to Necterosoma regulare, but is less convex, has the sides of the thorax quite simple, and the male characters rather more developed. Australia, 437. I. 39.— Genus MACROPORUS. The hind tibia has oidy the serial punctures on the infuro- external aspect ; the swimming legs are well developed, their femora being stout, and their postero- external angle sharply defined ; the terminal portion of tlie epipleura is rather broad, and the genicular area is not limited by a raised line. The mesosternal fork does not connect with the intercoxal process of the metasternum. The six species are found in Australia and Tasmania ; they are robust and large insects for the tribe ; and have the best developed swimming legs of any Hydroporini. 444. Hydroporus howittii, Clk., M.C. — Ovalis, minus latus, anterius angustatus, nitidus, tenuiter brevissime pubescens, testaceo-ferrugineus, elytrorum sutura plagisque posterius coalescentibus nigris ; elytris basi sparsim obsolete, apicem versus dense subtiliter punctatis ; coxis posterioribus sat fortiter punctatis. Long. 5i, lat. 3 m.ra. In the male the front and middle tarsi are much dilated ; the first joint of the front ones is particularly broad, the second strongly transverse, the third broad and not greatly developed, the claws of the fourth joint are very unequal, the anterior one being much the shorter and very abruptly curved. The female is not quite so shining as tlie male and has the punctuation of the elytra denser. The species does not appear to be a very variable one, though the colour of the under surface varies from clear unicolorous red, to a red clouded with infuscations here and there. Tasmania, Australia. 413. 44.^. Hydroporus hamatiis, Clk., M.C. — Oralis, robustus, tenuiter pubescens, dusniti vel opacus, colore variabilis, pedibus antennisque riifis, his versus apicem fuscis, elytris fere sequaliter, subtiliter sat crebre punctatis ; coxis posterioribus sat fortiter punctatis; abdoniiiie obsolete punctate. Long. 5j, lat. 3J m.m. On Aquatic Carnivorous Coleoptcra or Dytiscidce. 417 This species is closely allied to Hydroporus howittii, but it is always different in colour, and may be readily distinguished by the more even punctuation of the elytra, the punctures being more distinct at tlie base, and less dense towards the extremity ; the colour is blackish, with the head red, the thorax varying from red to fuscous black, the elytra black, often with the outer margin and two longitudinal stripes yellow, the undei'side blackish more or less diluted with red. The male has the front and middle tarsi dilated ; the third joint of the front one being rather larger in comparison with the basal ones than in H. howittii, the claws are less unequal than in H. howittii. There are two forms of the female, one with the surface differing but little from that of the male, while the other is dull and more densely punctured and pubescent. Tasmania and Soutliern Australia. 414. 446. Macroporus lateralis, n. sp. i^ — Ovalis, robustus, tenuiter pubescens, dense punctatus, subopacus, fusco-ferrugineus, capite, pedibus thoraceque rufescentibus, hoc medio late infuscato, elytrorum limbo fusco-testaceo, antennis rufo-fuscis basi rufo ; coxis posterioribus sat fortiter punctatis ; abdomine obsolete punctato. Long. 5f, lat. 3 A m.m. The only individual I have seen seems to indicate a species distinct from H. hamatus ; it is rather larger and is intermediate in appearance between the two female forms of that species ; the tarsi are rather differently formed, the terminal joint on the front and middle ones being less elongate than in H. hamatus. This individual had been named H. gardnerii by the late Mr. Clark. West Australia. 415. 447. Hydroporus gardnerii, Clk., M.C. — Ovalis, robustus, tenuiter pubescens, crebrius sat fortiter punctatus, subnitidus, nigricans, capite thorace, antennis pedibus que rufis, antennis versus apicem, vertice, et thorace anterius et posterius fuscis, elytris margine sordide pallido ; coxis posterioribus fortiter punctatis ; abdomine evidenter punctato. Long. Q\, lat. 3f m.m The front and middle tarsi are dilated in both sexes ; but are broader in the male than in the female, and in the former sex the claws of the front ones are unequal, the anterior one being rather shorter and more curved than the hinder one. There are two forms of the female — a dull one and a shining one. The species is distinguished from H. hamatus, by its larger size and coarser punctuation. It varies in colour, but probably never has stripes on the elytra ; these are in some cases infuscate yellow, while in others the yellow colour is limited to the side margin. The tarsi are much broader in the female than they are in that sex of H. hamatus. Tasmania, New South Wales, (Adelaide). 416. 418 On Aquatic Carnivorous Coleoptera or Di/tiscid(e. 448. Macroponis solidus, n. sp. — Oralis, robustus, latus, minus elongatus, tenuissime pubescens, crebre fortiter punctatus, subnitidus, fusco-piceus, capite, thorace, elytris lateribus pedibusque minus Isete rufis, antennis fuscis, basi rufu, thorace auteriu.s et posterius fusco ; coxis posteriovibus fortiter punctatis ; abdomine sat evidenter punctate. Long. .5^, lat. 31 m.ni. 1 have seen but two mules of this sj^ecies, they are shorter in form, and smaller than that sex of Hydroporus gardnerii, and the tarsi are not quite so broad, so that I think the specimens indicate a distinct though very closely allied species. Australia, (King George's SotihiI). 417. 449. Macroporus ruficeps, n. sp. — Ovalis, minus latus, tenuissime pubescens, sat nitidus, crebre evidenter punctatus, piceo-rufus, capite pedibus antennisque rufis, elytris piceis, thorace ad latera et in medio plus minusve dilutiore ; coxis posterioribus sat fortiter punctatis ; abdomine subobsolete punctato. Long. 5t, lat. vis 3 m.m. In the male the front and middle tarsi are broader than in the female, they being in the latter sex rather slender, the claws of the front ones are but little unequal. The species varies a little in colour, size and punctuation. It closely resembles II. hamatus (Xo. 44.5), but is smaller and more obscure in colour, rather more closely punctured, and with the front and middle tarsi much more slender. I have only seen one form of female, which differs but little from the male except in the tarsal structure. Austnilia. -118. I. 40.— Genus DERONECTES. The ridge on inner face of wing-case is destitute of a ligula ; the posterior portion of the epipleura is narrow, and the humeral area is not limited externally by a raised line. The mesosternal fork does not connect with the intercoxal process of the metasternum. Most of the numerous species* (about 45) inhabit the European and Mediterranean regions, very few North America. They form four groups defined as follows : — * In addition to these tlie following sliould also be included in the genus : — Hydropoms angulipennis, Peyr. (No. 1341 huj. op.), Group 1 ; Sj'ria. — H_ydroporus depressicollis, Ros. (No. 13G0), Group 1 ; Spain. — Hydroporus dubius, AuLe (No. 13G5), 1 = No. 465 ; Africa. — Hydroporus fivirmairei, Lep. (No. 1370), ? = No. 456 ; Europe. — Hydroporus boristhenicus, Hoch. (No. 1347), 1 = No. 472 var.; Europe. — Hydroporus inconspectus, Lep. (No. 1380),? = No. 456; Europe. — Hydroporus infaustus, Clk. (No. 1384), near No. 494 ; Mexico. — Hydroporus lanceolatus, Walk. (No. 1390); Arabia. — Hydroporus mcestus, Walk. (No. 1399) ; Arabia. — Hydroporus piochardi, Regt. (No. 1415),? No. 493 var.; Syria. — Hydi-oporus saiisi, Aube, (No. 1427),? No. 472 var.; Simin. — Hydroporus semiclusus. Walk. (No. 1430); Arabia. — Hydroporus subtruncatus, Fairm. (No. 1438),? = No. 469; North Africa. — Hydroporus undecimHnellus, Fairm. (No. 1445),? No. 490 var.; North Africa. — Hydropoms vestitus, Gebl. (No. 1448), Group I; Siberia. — Hyphydrus hyperboreus, Gyll. (No. 1464),? No. 471 var.; Lapland. Perhaps also Hydroporus stcarinus, Kol. (No. 1433), Caucasus, may be a Deronectes. On Aquatic Carnivorous Coleoptera or Dijtiscidoe. 419 Group 1. (Species 450 to 461). Swimming legs very slender, their tarsi slender and elongate, very distinctly longer than the tibiao ; the latter with the lower face densely punctured ; prosternal process narrow, carinate along the middle, often much compressed laterally, never quite flat, its form more or less obscured by fine setae ; elytra not denticulate near the apex; surface of body very dull, the upper one bearing a more or less distinct bloom or tomentum, which is very easily removed by friction ; the surface uni- colorous, or nearly so, always destitute of any definite marks or pattern ; sexual disparities in legs and feet scarcely to be detected, but often very remarkable as to the form of the prothorax. The species are about twelve in number, and are all found in clear runnino- streams in the European and Mediterranean region. Group 2. (Species 462 and 463). Hind coxae distinctly separated by a partition projecting backwards beyond the coxal cavities ; hind tibiae densely and finely punctured on their infero-external aspect, but allowing the series of punctures near the edge to be seen ; prosternal process remarkably broad and flat, without central carina ; colour of surface variegate. The species are only two in number; and both are European. Group 3. (Species 464). Hind tibiae coarsely punctate on the infero-external face, with, however, the marginal series of punctures visible at the upper edge of the punctuation : hind coxal cavities not visibly separated ; elytra with a vague yellow pattern ; prosternal process not very broad and flat. This species is found in the Canary Islands. Group 4. (Species 465 to 494). Hind tibiae with their infero-external face glabrous, and shining ; hind coxal cavities not visibly separated, prosternal process neither large, nor broad and flat, elytra always variegate with yellow or red. This group comprises the greater number of the species of Deronectes, and they will be arranged according to whether the elytra have a minute sharp denticle near the extremity, or are without such denticle. This is not a very good character as there are a few sjaecies in which the denticle is very obscure, and some others in which it is distinct in one sex, and less so in the other ; if however a careful examination be made the observer will not have much difficulty in decidino- to which of the two categories he should refer the individual under examination. A, elytra with a denticle near the extremity : species 465 to 484. B, elytra without a denticle near the extremity : species 485 to 494. TRASS. nOY. DCB SOC, N.S., VOL. II. 3 I 420 On Aqttalic Carnivorous Colcoptcia or Dytiscidce. Group 1. 450. Deronectes longipes, n. sp. — Oblongo-ovalis, angustulus, depressus, subtus nigricans, supra fuscus, opacus, dense, subtilissime breviterque pubescens, antennis pedibusque rufis, illis articulis terminalibus extrorsum fuscis ; prothorace elytris multo angustiore, lateribus sinuatis, basin versus angustatis, angulis posterioribus rectis ; elytris obsoletissime dense punctatis, serie discoidali punctorum impressorum distincta ; corpore subtus subtilissime punctato. Long. 4, lat. 2 m.m. The male has the front and middle tarsi very distinctly broader than in the female, and the fifth to the seventh joints of the antennae are distinctly longer and thicker than the others, whereas in the female this character can scarcely be observed. The species is remarkable amongst its allies for the narrow, depressed form, and the absence of larger punctures on the elytra. Persia. 297. 451. Dei'onectes planicollis, n. sp. — Oblongo-ovalis, sat angustus et depressus, subtus nigricans, supra fusco-rufus, antennis pedibusque rufis, opacus, dense, sub- tilissime brevissimeque pubescens, subtilissime punctatus, capitc thorace elytrisque punctis majoribus adspersis, sat numerosis ; prothorace elytris multo angustiore, lateribus sinuatis, basin versus leviter angustatis, angulis posterioribus rectis ; elytris serie discoidali obsoleta. Long. 5, lat. 21 m.m. The male has the front and middle tarsi strongly dilated ; and the anterior claw of the front feet is much incrassate. I have seen but a single individual of the species ; although closely allied to H. parvicollis, Schaum, it is smaller and narrower, and has the thorax less sinuate at the sides, and the anterior claw on the male foot incrassate : the thoracic side margin is very fine, and there is scarcely any trace of impression along the side within it. Asia Minor. (Coll. Wehnoke). 208. 452. Hydroi)oras p.irvicollis, Schaum, M.C. — Oblongo-ovalis, robustul'is, parum depressus, subtus nigricans, supra fusco-rufus, opacus, dense, subtilissime bi-evi.ssime- (^e pubescens, antennis pedibusque rufis, illis crassiusculis ; prothorace elytris multo angustiore, lateribus sinuatis, basin versus angustatis, angulis posterioribus rectis ; capite fortiter punctato ; thorace basi fortiter sed subobsolete punctato ; elytris subtilissime punctatis, punctisque subtilibus obsoletisque tantum ad basin distinctis impressis, sulculaque discoidali sat distincta. Long. 5, lat. 22 m.m. The only individual I have seen is a typical specimen of Schaum's, it is no doubt a male, and has the front and middle tarsi rather broad. On Aquatic Carnivorous Colcoptcra or JhjtiscidcB. 421 The species is about the size of Hydroporus lareynei, (No. 454), but it is very readily distinguished from it by the narrower head and thorax, the latter having the sides simple without the broad explanate lateral portion. Asia Minor, (Natolia). 1 141. 453. Deronectes dorite, n. s^). — Oblongo-ovalis, sat angustus et depressus, nigricans, opacus, dense subtilissimeque pubescens, densissime subtilissimeque punctulatus, punctis majoribus obsoletis ; antennis pedibusque rufis ; prothorace elytris multo angustiore, lateribus sinuatis, basin versus leviter angustato, angulis posterioribus rectis, posterius intra latus impresso. Long. 41, lat. 2 m.m. I do not know the sex of the only two individuals I have seen. Caucasus, (found by the Marquis Jacques Doria). 307. 454. Hydroporus lareynei, Fairm., M.C. — Oblongo-ovalis, subdepressus, subtus nigricans, supra vel rufescens vel fusculus, antennis pedibusque rufis, opacus, dense subtilissime pubescens, subtilissime punctulatus, sed supra punctis majoribus sat nuraerosis et conspicuis ; prothorace elytris paulo angustiore, lateribus sat ex- planatis, rotundatis, basin versus angustatis, angulis posterioribus obtusis. Long. 5, lat. 2f m.m. The male has the front and middle tarsi strongly dilated, the antennas elongate, with the intermediate joints thickened, and the thorax gradually and gently narrowed from the midddle to the base, while in the female the contraction in front of the base is much greater and more abrupt : this difference in the form of the thorax is so striking, that Reiche considered that sex to be a distinct species, and gave it the name of Hydroporus coarcticoUis. Corsica. 299. 455. Hydroporus opatrinus, Germ., M.C.^Oblongo-ovalis, nigricans, opacus, pruinoso-pubescens, antennis pedibusque rufescentibus, vel fere nigricantibus ; dense subtiliter reticulato-punctatus, supra punctis magnis, numerosis, conspicuis ; elytris sulca longitudinali sat distincta ; coxis posterioribus punctis majoribus obsoletis ; thorace basin versus angustato, angulis posterioribus fere rectis. Long. 5^, lat. 3 m.m. In the male the thorax is less narrowed at the base than it is in the female, so that the hind angles are distinctly obtuse ; the presternum bears on the middle between the front coxse an acute tubercle ; in the female the thorax is narrower at the base, and the hind angles form a sharp angle which is very nearly a right angle, and there is no prosternal tubercle. :! I -i 422 On Aquatic Carnivoroxis Coleoptera or DytiscidcB. The female seems to be the Hydroporus hispanicus of Rosenh., and is considered a distinct species by Leprieur. Southern Europe ; from Geneva to Spain. 301. 456. Hydroporus moestus, Fairm., Ann. Soc. Fr. 1S59, p. 272. — Oblongo-ovalis nigricans, opacus, dense niiiuis subtiliter pruinoso-pubescens, dense subtilissime punctatus, et supra in thorace et elytris punctis majovibus plus minusve conspicuis, (sed interdum fei'e nullis) ; elytris sine sulca longitudinali ; prothorace lateribus basin versus baud vel leviter angustatis, angulis posterioribus leviter rotundatis ; corpore subtus densissime reticulato-punctato. Long. 5, lat. 2 J, m.m. The sexual characters are very slight, the male is generally a little smaller than the fsmale, and the sides of the thorax being a little less rounded or contracted behind its angles are more nearly rectangular. This species varies greatly according to locality ; the individuals from Corsica and Majorca at first sight appear quite distinct from those from the Western Pyrenees, as they are smaller, and have the coarse punctuation much reduced, but all the intermediate steps may be found when the specimens from north-western Italy and Sardinia are examined. I believe Hydroporus fairmairei and H. inconspectus, Lep. (Nos. 1370 and 1380) are varieties of this species. Europe and Egypt, (Bondy, Paris?; Geneva, Lombardy, South of Fiance, Corsica, Sardinia, Majorca, Malaga, Algeria). 303. 457. Hydroporus bombycinus, Lej)., Ann. Soc. Fr. 1876, p. cxxii. — Ovalis, vix omnino opacus, densissime subtiliter pruinoso-pubescens, nigricans, dense subtil- issime punctatus, punctis majoribus vix conspicuis, vel omnino nullis ; prothorace brevissimo, posterius baud angustato, sed angulis posterioribus late rotundatis ; corpore subtus subtilissime dense reticulato-punctato; jjedibus vel nigricantibus vel flavis. Long. 4i, lat. 2? m.m. The thorax appears in the larger specimens to be rather more narrowed towards the front, and these are probablj' the females. This species is very close to Hydroporus moestus, but the rounding of the hind angles of the thorax is greater, and the surface is more silky and less opaque, and the minute punctuation is rather different in character, and the coxal lines of the hind coxae are move approximate, and less divergent in front. Southern Europe, and Algeria, (Bcziers ; Lombardy ; Andalusia; Bou-Saada). 30G. 458. Hydroporus semirufus. Germ.; M.C. — Oblongo-ovalis, vel rufescens, vel fusculus, vel niger, antennis pedibusque rufis, subtiliter pruinoso-pubescens, dense subtilissime punctatus, et in thorace elytrisque fortiter punctatus ; elytris sulca basali On Aquatic Carniv)rous Coleoptera or Di/tiscidce. 42:3 obsoleta; subtus dense reticulato-punctatus, coxis posterioribus interne punctis majoribus conspicuis ; protborace basin versus nullo modo angustato, angulis posterioribus rectis ; elytris bumeris emarginatis. Long. 43, lat. Si m.ra. I do not see any evident sexual distinction in tbis species. Central and Southern Euroi>e ; (Black Forest; GranJe Chartreuse; Alps; Pyrenees; Reynosa ; Italy), 304. 459. Hydroporus platynotas, Genu., M.C. — Subquadrato-ovalis, niger, opacus, subtiliter in'uinoso-pubescens, antennis pedibusque rufescentibus, dense subtilissime punctatus et supra, praesertim in elytris, fortiter punctatus ; elytris sulca basali longitudinali subobsoleta ; subtus dense subtiliter reticulato-punctatus, coxis posterioribus interne punctis majoribus minus, vel vix, conspicuis ; protborace basin versus baud angustato, sed angulis posterioribus subrotundatis. Long. 4, lat. 2 J m.m. Tbe sexual characters are but slight, the male is rather narrower than the female, and has the middle joints of the antennae more developed and the thorax a little straisfhter at the sides. o Central Europe ; (apparently confined to Germany). 303. 460. Hydroporus bicostatus, Schaum, M.C. — Oblongo-ovalis, nigricans, vel rufescens, opacus.. subtilissime pruinoso-pubescens, thorace elytrisque fortiter crebre punctatis, elytris medio costa longitudinali, elongata, bene elevata, aliaque externa, abbreviata, obsoleta; subtus dense subtiliter reticulato-punctatus, coxis posterioribus punctis majoribus sparsis sat conspicuis ; protborace basin versus baud vel vix angustato, angulis posterioribus baud rotundatis. Mas, angustior, nigricans. Long. 4l, lat. 2l m.m. Fern., latior, rufescens. Long. 5, lat 2| m.m. Besides the difference in colour and stature, tbe male has the thorax not narrowed towards the base, and has a minute tubercle on the presternum, while the female is without this tubercle, and has the thorax just a little narrowed from the middle to the base. Spain and Portugal, but very local ; in running streams. 302. 461. Hydroporus latus, Steplj., M.C. — Latiusculus, minus depressus,''subopacus, ferrugineus, vel fusco-ferrugineus, elytris magis fuscis bumeris rufescentibus, antennis pedibusque dilute rufis ; tenuissime vix jierspicue pubescens, corj^ore subtilissime dense punctulato, sed supra punctis majoribus, profundis, numerosis conspicuis adsperso. Long 4i, lat. 21 m.m. In tbe male the front and middle tarsi are still broader than they are in the 424 On Aquatic Carnivorous Coleoptera or DytiscldcB, female, and the front ones have the claws longer and stouter ; the thorax is not narrowed in front of the base so that its hind angles are free, the base being a little wider than the shoulders of the elytra ; in the female the sides are a good deal contracted just in front of the base so that the angles fall within the shoulders of the elytra ; in the female there is a short indistinct plica near the outer edge of the elytra at some distance before the apex, and the last ventral segment is a little prominent on each side. Central Europe ; (widely distributed but rare ; from Scotland to Italy, and from Dalmatia to La Vendue). 300. Group 2. 462. Dytiscus duodecim-pustulatus, Fab., Hydroporus duodecim-pustidatus, M.C. — Oblongo-ovalis, sine pubescentia, sub-opacus, testaceo-ferrugineus, thorace anterius et posterius nigricante, elytris fusco-nigris, maculis fere quadratis testaceis ornatis ; thorace lateribus valde rotundatis, angulis posterioribus obtusis ; corpora subtilissime punctulato. Long. 5i, lat. 2f m.m. Mas, tarsis anterioribus et intermediis bene dilatatis, anterioribus unguiculis majoribus, tibiis anterioribus et intermediis intus leviter curvatis, intermediis angulo apicali interno unco parvo armatis. This species varies a good deal in colour, the elytra being sometimes nearly entirely yellow while in other individuals tlie black colour occupies nearly all their surface ; the underside also is more or less infuscate. Central and Southern Europe, (and Algeria ?) ; extends in the north to Scotland, and south of Swedeu, wanting in Finland. 240. 463. Hydroporus duodecim-maculatus, Eegt. Ann. Soc. Fr. 1877, p. cxxxiii. — Oblongo-ovalis, sine pubescentia, testaceo-ferrugineus, capite intra oculcs, vertice, thoraceque anterius et posterius nigro-marginatis, elytris nigris, maculis plus minusve conspicuis testaceis ornatis ; thorace lateribus valde rotundatis, angulis poster- ioribus fere rotundatis ; corpore subtus plus minusve infuscato. Long. 5|, lat, vix 3 m.m. Mas, paulo longiore, tarsis anterioribus et intermediis bene dilatatis ; tibiis intermediis intus curvatis, angulo apicali interno unco parvo armatis. Fern., opaca omnium dense subtilissime punctata. Although very closely allied to Dytiscus duodecim-pustulatus the sj^ecimens before me of this species differ not only by their more rounded hind angles of the thorax, but also by the sexual characters, the male front claws being shoi'ter, and the anterior tibiae not curved inwardly, while the female differs more in appearance from the male owing to the punctuation of the surface being more obsolete. The colour no doubt varies a good deal. On Aquatic Carnivorous Coleoptera or Dijtiscidce. 425 The above description is made from Corsican individuals. The only specimen I have seen from North Africa differs so much from them, that it may be another species. Corsica, (E. Eeveliere) ; Tangier? 1142. Group 3. 464. Hydroporus tessellatus, Aube, M.C — Elongato-ovalis, depressiusculus, dense subtilissime pubescens, fere opacus, niger, supra indistiucte testaceo-variegatus, antennis pedibusque rufescentibus ; thorace lateribus sat rotundatis, angulis posterioribus distinctis, obtusis ; corpore dense subtilissime punctulato, thorace basin versus punctis majoribus sat conspicuis. Long. 5i, lat. 2l m.m. The male has the front and middle tarsi broad ; the claws of the front ones are more developed than in the female and the anterior one is dilated at the base so as to show there an angular projection ; in this sex the apex of the elytra is slightly sinuate, while in the female there is a very indistinct tooth near the extremity of each. Canary Islands. 249. Group 4. 465. Hydroporus vigilans, WoU., M.C. — Ovalis, depressiusculus, vix pubescens, yel sat nitidus ('3. ROY. DUD. SOC, N.S., VOL. II. • 3 R 4St On A(jiiniic Curniroroiis Coleoi>tevn or DijliscidiB. The male has the front and middle tarsi rather strongly dilated, and the front tibire excised at the base inwardly : the only female individual I have seen is dull and opaque, but distinctly punctured, its front tibia; are not excised. Though very closely allied to Hydroporus coUaris, the species is quite distinct. . North America, (United States). -10:^ Gi:on' S. G40. Hydroporus terminalis, n. sp. — < )s-alis, angustulus, minus convexus, sine pubescentia, subnitidus, abdomiue pectoreque nigris, supra fusco-testaceus, pedibus sordide rutis, antennis fuscis basi testaceo ; prothorace valde transverse, inconspicue punctato ; elytris crebre subtiliter punctatis, punctis versus apicem magis conspicuis; coxis posteriori bus sat evidenter punctatis. Long. 3, lat. 1^ m.ni. The front tarsi in the male are rather broader tlian in the female. This species is extremely similar to Hydroporus vilis, Lee, but is a little narrower, the antennre are darker in colour, the punctuation is ruther more conspicuous, and all the tarsi are smaller. North America, (California). 404. 641. Hydroporus vilis, Lee, M.C — Ovalis, minus convexus, sine pjubescentia, subnitidus, abdomine pectoreque nigris, s'i[)ra fusco-testaceus, antennis pedibusque rufis; prothorace obsolete punctato; elytris minus crebre subtiliter punctatis; coxi.s posterioribus obsolete punctatis. Long. :3, lat. Is m.m. I am scarcely able to distinguish the sexes of this species. Nortli America, (California, Utah)- 40r>. 642. Hydroijorus latebrosus, Lee, M.C. — Ovalis, minus convexus, latiusculus, sine pubescentia, subnitidus, abdomine pectoreque nigris, supra fusco-testaceus, antennis pedibusque sordide rufis ; elytris .sparsim subtilius punctatis ; prosterni processu angusto ; coxis posterioribus obsolete punctatis; abdomine .segmonto ultimo fere impunctato. Long. Hi, lat. 2 m.m. The two individuals before mo arc I tiiiidv male and female, though extremely similar to one nnotlier. Tlie species is extremely close to H. vilis, but is larger and relatively very much broader. A specimen has been determined for me by Lccontc, otherwise I should not have recognized the name from description. North America, (C.ilifornia). 4(16. 643. Hydi'oporus hardyi, n sp. — Ovalis, minus convexus, latiusculus, sine pubes- centia, subnitidus, abdomine pectoreque nigri.s, antennis pedibu.squc rufis ; elytris On Aquatic Carnivorous Coleoptera or Dytiscidw. 485 sparsiru subtilisslme punctatis ; pro.bterui processu latiusculo ; coxis posterioribus subtiliter punctati? ; abdomine segmeiito ultimo confertim subtiliter punctato. Long. 4, lat. 21 iii.m. I have seen only one individual of this, the largest species of the group, it is rather larger than our European H. lituratus (No. 5G9). North Ameiica, (California, found by Mr. H.ardy). 407. G44. Hydroporus belfragei, n. sp. — Oblongo-ovalis, depressus, sine pubescentia, subnitidus, ferrugineus, abdomine pectoreque nigris, elytris furrugineo-testaceis ; ubique parce obsoleteque punctatus. Long. 3, lat. Ij m.m. I have seen but a single individual of this distinct species, though allied to H. vilis (No. G41), it is more depressed, brighter coloured, and has the prosternal process rather more elongate, and distinctly carinate along the middle near the apex. North America, (Texas, sent by Belfrage). 408. GllOUl' 9. 645. Hydroporus difformis, Lee, M.C. — Oblongo-ovalis, elongatus, sine pubes- centia, sat nitidus, piceus, supra dilutior, antennis pedibusque rufis ; elytris crebre paruni subtiliter, distincte punctatis, punctis apicem versus paulo crebrioribus ; corpore subtus nitido, subloevi, abdominis lateribus strigulosis. Long. 5 1, lat. 3 m.m, I have seen only a single individual of this large and remarkable species, which by its appearance calls to mind the estriate Copelati ; the specimen is probably a female. The species seems to be very pe3uliar, and will no doubt prove generically distinct, meanwhile it appears best placed near H. oblongus, from which it differs by the rather widely separated middle coxaj, the very large prosternal process, Avhich is elevated at the sides and along the middle, and terminates iu front as a strongly elevated projection ; the metasternum is broadly but obscurely depressed in the middle in front ; and the coxal lines are but little turned outwards near the extremity. The highly developed coxal lobe, with very rounded extremity quite pi-otects the articular cavity, as in H. oblongus. North America, (Georgia, Boston). 2G8. 646. Hydroporus oblongus, Steph., M.C. — Oblongo-ovalis, elongatus, sine pubescentia, nitidus, niger, supra fusco-castaneus, antennis pedibusque rufescentibus, elytris sparsim distincte, apicem versus crebrius punctatis ; corpore subtus fere impunctato. Long. 5, lat. 2.1 m.m. 3 R 2 48<) On Aquatic Cavuivorous Coleoptera or Dijtiscidai. The male has the front and middle tarsi a little dilated, and the inner claw of the front foot longer and thicker than the outer ; joints 3-7 of the autennsB are shghtly stouter than in the female. I am not quite sure that the North American specimens may not prove a distinct species, hut I have not specimens of this rare species sufficient to judge from. Leconte has called this North American form H. conoideus. Northern Europe, Siberia, aud Vortli America. (Sweden : Finland, to GG' 20' North, Sahlberg ; Britain, Germany, Canada, Lake Superior, Vancouver's hind). 221. 647. Hydroporus luguhris, Aube, M.C. — Oblongo-ovalis, elongatus, sine pubes- centia, sat nitidus, nigricans, elytrorum epipleuris clypeoque antorius dilutioribua, antennis pedibusqus ferrugineis ; prothorace subtilissime sparsim punctulato, f lytris sparsim conspicue punctatis ; co.xis posterioribus evidcnter elongato-punctatis ; prosterni processu evidenter tricarinato. Long, il, lat. 2m m.ni. South -Vnierica, (Monte Video). 22G. 648. Hydroporus copelatoides, n. sp. — Oblongo-ovalis, elongatus, sine pubosccntia, sericeo-subopacus, nigricans,antennis pedibusque rufesccntibus, corpoi-e supra sparsim subtiliter punctato, subtus fere impunctato, punclis elytrorum subelongatis; prosterni processu medio fortiter carinato. Long. 45, lat. 2| m.m. This species bears much resemblance to the European and North American Hydroporus oblongus, but the prosternal process is more carinate along the middle. Chili. 225. 649. Hydroporus advena, n. sp. — Ovalis, sine pubescentia, sat nitidus, niger, supra fusco-testaceus, prothoracis macula magna discoidali elytrorumque sutura ano'ustissime nigricantibus ; thorate subtilissime punctulato, elytris sat crebre et sat fortiter punctatis, punctis subelongatis; corpora subtus nitido fere impunctato ; coxis intermediis sat distantibus, prosterni processu apicem versus latiore; pcdibus antennarumque basi testaceis. Long. 2f, lat. l\ m.m. In the male the front and middle tarsi are a little dilated. South -Vfriea, (Cape Town). 228. On Aquatic Carnivorous Coleoptera or Dijtiscid(s. 487 I. 4-2.— Genus CELINA. Scutellum large, exposed ; front and middle tarsi five-jointed, the three basal joiata broader than the two apical, the third emarginate or sublobed, the fourth smaller than the others, the fifth elongate ; swimming legs slender and feeble ; body ter- minating in a spine. This genus is represented by seven species,* all very rare in collections ; and very similar to one another ; the appearance and size is that of narrow, suboblong Hydropori. They are peculiar to the warm parts of the New World, one species extendiniif to the United States of North America. G50. Celina aculeata, Aube, M.C. — Suboblonga, elongata, nitida, glabra, rufo- castanea, elytris paulo obscurioribus ; antennis testaceis, clongatis, articulo sino-ulo latitudine distincte longiore ; prothorace versus margines evidenter, disco subtilissime, punctate ; elytris crebre et distincte fere asqualiter punctatis, serie punctorum majorum fere nullo ; corpore apice longius mucronato. Long. 5, lat. 2j m.m. i/as, tarsis anterioribus et intermediis fortiter dilatatis ; tibiis intermediis intus curvatis, medio incisura parva, parte basali tenui, apicali lata. 8outli Americn, (Brazil). .598. G.jl. Celina mucronata, n. sp. — Suboblonga, sat elongata, nitida, glabra, castanea, capite thorace pedibusque rufis ; antennis testaceis, mediocritcr elono-atis ; prothorace margine anteriore serie punctorum, anteque basin utrinque punctato ; elytris basi parce, apice crebre punctatis, serie punctorum discoidali distincta. Long. 4i, lat. 2J- m.m. Mas, tarsis anterioribus et intermediis fortiter dilatatis ; tibiis intermediis latis, simplicibus. This species is not quite so elongate in form as the preceding one, and is readily distinguished by the different punctuation of the elytra, and the simple intermediate tibite of the male. I have seen but one specimen. South America, (Constant ia, June, 1850, Salilberg). 597, 6.52. Celina longicornis, n. sp. — Suboblonga, sat elongata, nitida, glabra, rufo- castanea ; antennis testaceis, elongatis ; prothorace versus margines punctato ; *And also by the following three, unlmowTi to me: Celina gros.sula Lee. (No. 1209); North America. — HyJroporomorpha parallela Bab. (No. 133G) near No. 652; Brazil. — Hydroporu.s latipes Brulle (No. 1393) ; Corrientes. -iSS On Aquatic Curnicorous Coleoptera or Di/tiscidce. elytris crebre fere sequaliter punotatis, serie discoidali punctorum fere nulla. Lonj?. Al, lat. 2 m.iu. Mas, tarsis anterioribus et intermediis fortiter dilatatis ; tibiis interniediis intus curvatis, medio incisura parva, parte basali teiiui, apicali lata. This species is also very closely allied to Celina aculeata, but is less elongate, and the base of the thorax is more thickly puncturel in the middle. The mucro at the extremity of the body is here quite short, but I am not sure but that is partly owing to the retraction of the aedeagus. South America, (Santa Rita, September, 1850, Sahlberg). .598. G53. Celina picea, n. sp. — Suboblonga,elongata, angustula, pernitida, glabra, picea, pedibus rufis ; antcnnis baud elongatis testaceis ; j^i'othorace paululum punctato ; elytris parce punctatis, sod puuctis ad apicem paulo crebrioribus, serie punctorum discoidali distincta ; corpore apice breviter mucronato. Long. 4i, lat. 2 m.m. , }fas, tarsis anterioribus et intermediis bene dilatatis ; tibiis intermediis abrupte curvatis, medio incisis. The thorax in this species is quite without punctuation in the middle at the base, ■and even the anterior marginal punctures become obsolete in the middle. The bending of the male middle tibia is so extreme, that the basal portion is nearly at right angles with the apical portion. South America, (Petropolis, March, 1850, Sahlberg). 559. C54. Celina crassicornis, n. sp. — Suboblonga, sat elongata, angustula, nitldn, glabra, picea, pedibus rufis ; antennis testaceis, brevibus, crassiusculis, articuli.s penultimis latitudine longitudine fere tequali; prothorace paululum punctato; elytris parce subtiliter punctatis, sed punctis ad apicem paulo crebrioribus, serie puiutorum discoidali sat distincta. Long. 4, lat. vix 2 m.m. Mas, incognitus. This species is closely allied to Celina picea, and it possibly may be only the female thereof, but it is less elongate, and has the antennae shorter and thicker, and the punctuation of the elytra is rather finer. South America, (Petropolis, March, 1850, F. Sahlberg). GOO. : 655. Celina bonvouloiri, n. sp. — Suboblonga, elongata, angustula, nitida, glabra, rufescens, elytris paulo obscurioribus ; prothorace paululum punctato; elytris parce subtiliter punctatis, ad apicem fere impunctatis, stria discoidali distincta. Long. 4, lat. H m.m. Mas, tarsis anterioribus et intermediis fortiter dilatatis ; tibiis intermediis curvatis, medio incisura parva, parte basali tenui, apicali lata. On Aquatic Carnivorous Coleoptera or Dijliscidce. 489 This species has the anteante rather long and slender; the punctuation of the upper surface is less than in the other species. I have seen but a single individual. Cayenne, (coll. de Bonvouloir). 601. 65G. Celina angustata, Aube, M.C. — Suboblonga,elongata, angustula, subdepressa, nitida, glabra, rufo-testacea, el3'tris paulo obscurioribus ; antennis sat elono-atis ; prothorace paululum punctato ; elytris sparsini, sat subtiliter punctatis, punctis apiceni versus subbilioribus sed vix crebrioribus, stria discoidali sat distincta. Lono-. 3f, lat. It m.m. Mas, tarsis anterioribus et intermediis sat dilatatis ; tibiis intermediis curvatis, medio incisura parva, parte basali tenui, apicali lata. ' This species is smaller than any of the others, and has the prosternal process distinctly narrower. I have seen but a single specimen in Dejean's collection ; an individual in the collection of the Brussels Museum, labelled " Hyd. xantholoma Chev. Pernambuco," .scarcely differs however except by its more castaneous colour, and slightly coarser punctuation of the elytra, so tliat I consider it only a variety of this species. ' South Americ;!, (Cayenne, Pernambuco) ; North America, (United Stat3s). 602. I. 43.— Genus MFAIILES. Scutellum concealed, base of thorax acuminate and pioduced in the middle. Front and middle tarsi five-jointed, subcylindrical, the basal joints beino- without dilatation, and without clothing beneath, the third not at all bilobed. Swimmino- legs very feeble ; extremity of body s))inose. Three species are included in this di-stinct and peculinr genus ; they have the size and form of small Hydropori ; but the body being acuminate or spinose at the apex, they look still more like Celinje. The species are found in tropical Africa, Madagascar, Mesopotamia, and Eo-ypt. 657. Methles spinosus, n. sp.— Eufescens, glaber, sat nitidus, capite thoraceque lajvibus, elytris sparsim sat fortiter punctatis ; subtus fere impunctatus ; prothorace lateribus leviter rotundatis, angulis posterioribus obtuse rectis. Long. 3, lat. 1 i m.m. Head large impunctate. Thorax impunctate, the base pointed in the middle, the hind angles closely applied io the shoulders of the elytra, the sides but slio-jitlv 490 On Aquatic Carnivorous Coleoptcra or Dytiscidce. rounded. Elytra narrow and elongate, rounded at the sides, narrowed and acuminate behind, sparingly punctured, the punctures more distinct towards the extremity than at the base ; abdomen terminated by a long pointed spine directed backwards and upwards. Egypt — a suigle specimen, (probably from the neighbourhood of Cairo) sent by Dr. MiUingen. G03. 658. Methles rectus, n. sp. — E,ufe3cen.s, sat nitidus, glaber, capite thoraceque fere impunctatis; elytris sparsim sat fortiter punctatis ; subtus fere impunctatus ; prothorace lateribus rectis, angulis posterioribus rectangulis. Long. Si, lat. If m.m. Closely allied to the preceding species, but rather larger and with the thora.K quite straight at the sides ; the mucro terminating the body is much shorter, but this may perhaps not be a specific character. Mesopotamia, also a discovery of Dr. Millingen's. 004. 659. Methles punctipennis, n. sp. — Suboblongus, sat nitidus, glaber, capite thorace- que fere impunctatis, hoc tamen versus latera punctis paucis ; elytris crebre fortiter punctatis ; corpore subtus fere impunctato ; thorace lateribus paululum rotundatis, angulis posterioribus obtuse rectis. Long. 3s, lat. lA m.m. Very similar indeed to the other two species, but with much more distinct punctuation on the elytra. Tropical Africa, (Lagos, Ashautee). 605. in. 3.— Tribe COLYMBETIDES. Last abdominal stigma of small or moderate size ; outline of eye in front invaded by the free margin of the clypeus, so that it is notched or emarginate not circular ; feize moderate, 20 m.m. of length being attained by only three or four species. .Posterior femora with aggregated cilise arranged in a linear grouj) at the | AoAlilNI. postero-cxtemal angle. f (Vide p. i'3\.) Upper and inner edge of first ventral 1 plate without transverse folds or I GeNER.\, 54 to 60. grooves: size rather below the aver- !- / f 7 r/>i \ , , , . . ,,, £ 1 ( I if/e p. 561.) age, rarely attaniing ill 111. m. of ' ' Posterior femora without aggregated ^ length. j ciliae at the postero-external angl Upper and inner edge of lirst ventral 1 plate with transverse folds: size I CoLYMBETINI. quite the average, usually attain- | ( Vide p. 605.) ing 10 m.m. or more of lengtli. J On I quatic Carnivorous Coleoptera or Dytiscidw. 491 II. 10. — Group Agabini. No stigmatic rugee ; that is to say, the semi-membranous piece bordering the inner edge of the first ventral plate is smooth; wing of the metasternum reaching, when the elytra are closed, as far outward as the margin of the epipleura. Hind femur on the under surface with a group of cilise more or less developed, and situate quite close to the hind margin at the outer part of the femur. Side piece of the fourth and following ventral segments rather broad, (the length of the fourth being only about twice its breadth). The character by which a member of this group may be mo^t readily recognised is the group of cilite at the angle of the hind femur. Ten genera are included in the Agabini and they may readily be discriminated by the following table: a 13 .^ o S s " o O ^ ■— - P 'S o Ph .a 03 C3 M o O Palpi with theu- terminal joint dilated ; that of the \ labial veiy large and subquadrate. j O 0 5^ OJ S ^ « Coxal lines very deep and nearly straight. Coxal lines fine, sinuate. Epipleurse continuing rather broad 1 after the middle of -wing-case, i rr ?1 .^, j: CJ .— ^ ^ o .3 c .:=; 3 n* 'Tl c« 0) 43 X » o ni -*-> Sh a » o -3 a. o tT sr rS 01 60 a 2 .;2 o ^- ft 'Swimming legs short and stout ; thorax slightly margined at sides ; upper surface convex; size large (12 m.m. long.) Swimming legs rather slen-~ der ; thorax margined at sides ; upper surface rather flat ; size rather small (8 m.m. long.) ^ Thoi'ax not margined at i sides. I o " O o Hind coxa very large. ■% I Hind coxa small. HYDROTRUPES. {Videi>. 492.) AGABINUS. iVide^. 548.) AGABUS. (Vide p. 493.) PLAT AMBUS. ( Vide p. 548.) ILYBIUSOMA. (Vide IX 537.) PLATYNEGTES. (Vide\x 5.38.) LEURONECTES. (Vide p. 546.) AGAMETRUS. (Vide -p. 547.) METRONECTES (Vide -p. 492.) Posterior tarsi with their claws decidedly unequal ; and with 1 the lower part of the hind margin of their joints, on the outer l ILlBlUh. face, produced or lobed. j ( '^'^^ V- 550.) TBAN3. BOV. DUB. SOC, N.S., VOL. U, 3 S 492 On Aquatic Carnivorouti Coleoptera or iJytiscidtB. I. 44.— Genus IIYDROTRUPES. Labial palpi very sliort and stout, their terminal joint subquadrate. ()60. Hydrotrupes palpalis, n. sp.— Late ovalis, parum convexus, nitidus, subtus ferrugineus, pectore nigricante, supra jenescens, capite antrorsum prothoracisque lateribus ferrugineis, antennis crassiusculis pedibusque rufis ; capite thoraceque reticulatis, hoc margine laterali crasso, elytris crebre sat subtiliter punctatis, punctis seriatis fere nullis ; corpore subtus fere Ifevigato : tibiis anterioribus et intermediis extus conspicue spinosis. Long 4§, lat. 2§ ni.m. T have seen only one individual of this peculiar insect, the appearance of which suggests at the same time Hydrovatus and Agabus : the specimen is a male, and though the front and middle tarsi cannot be said to be incrassate yet the three basal joints bear beneath some glandular clothing. The numerous spines at the sides and apex of the front and middle tibiae are conspicuously developed. The very short and thick labial palpi, will readily allow the species to be identified. The outline of the thorax and elytra is completely continuous. North Ameiica, (California; coll. Wehncke.) 931. L 4.5.— Genus METRONECTES. Coxal lines and coxal border very obsolete, almost absent ; antennae and palpi short and stout ; hind coxa? but little developed, short, the anterior border but little arched : %\nnofs of metasternum large. The unique species inhabits Corsica. 661. Agabus aubei, Perris, Abeille, VII, p. 6. — Ovalis, minus convexus, nitidus, niger, antennis palpis pedibusque rufis, femoribus piceis, supra obsolete reticulatus, elytris punctis seriatis magnis ; prothorace cum elytris minus continuo, lateribus leviter rotundatis, angulis posterioribus obtusis ; antennis brevibus, incrassatis. Long. Q-7 , lat. 3§ m.m. The male distinctions are in this species extremely slight ; there is scarcely any incrassation of the Iront and middle tarsi, and only the two basal joints are furnished beneath with a small patch of short glandular hairs. The thickened antennae and pali)i of this species cause it to l)e very easily- recognized. Coi-sica. 832. On Aquatic Curnivorous Coleoptera or DytiscidcB. 493 I. 46.— Genus AGABUS. Side of prothorax with a raised margin ; labial palpi with terminal joint not incrassate ; wings of metasternum variable in size, but never so very short as to be parallel-sided ; coxal lines distinctly sinuate , hind tarsi on their outer side with the posterior margins of the joints nearly straight, not lobed. This genus consists of nearly a bunded species found in the northern parts of the Old and New Worlds ; it is one of much interest, but of extreme difficulty so far as regards the determination of the species, on account of the great similarity in general appearance, and the considerable variation in structural characters from species to species. I have arranged the species in twenty-three groups, some of them natural, some clearly artificial ; to tabulate these groups in an analytical manner would only confuse the student and lead him into errors of determination ; J have therefore contented myself with placing at the head of each group the characters that have induced me to adopt it. These characters are drawn largely from the coxal lines and processes, and the form of the anterior border of the hind coxee, the metasternal wings, the approximation of the middle legs, and development of the metasternal groove, and the prosternal process.* * The following species also probably belong to the genus Agabus. Agabiis amrenns, Solsky, (No. 1179 huj. op.) Turkistan. — Agabns atratus, Mann. (No. 1180); Russian America. — Agabiis confertus, Lee. (No. 1182) ; North America. — Agabus foveolatus, Muls. (No. 1185), very closely allied to No. 706; France.- — Agabus fnsco-senescens, Regt. (No. 1186) ? near No. 737; Austria. ^Agabus glacialis, Hoch. (No. 1187), near No. 671; Caucasus. — Agabus goryi, Aube (No. 1188), near No. 670; Smyrna. — Agabus gougeleti, Eeiche, (No. 1189)? No. 714 var. ; Corsica. —Agabus hoeffneri, Aub6 (No. 1190), near No. 720 ; Sweden. — Agabus irregularis, Maun. (No. 1193) ?=No. 688; North America. — Agabus kess- lei-i, Hoch. (No. 1194)1 near No. 757? Russia. — Agabus luniger, Kol. (No. 1196; ! No. 713 var. j Armenia. — Agabus morosus, Lee. (No. 1197)? near No. 707 ; North America. — Agabus opacus, Aube, (No. 1199); Finland. — Agabus rotiindatus, VVehncke (No. 1 200) ? near No. 694 ? Sardinia.- Agabus scapularis ; Mann. (No. 1201) i=No. 710; North America. — Agabus subopacus, Mann. (No. 1202); North America. — Agabus terminalis, Melsh. (No. 1204); North America. — Agabus venturii, de Bertolini (No. 1206) Italy. — Anisomera recta, Lee. (No. 1208), near No. 662; North America. — Colymbetes alpinus, Mutsch. (No. 1210) ?=No. 736? Mongolia.— Colymbetes basalis, Geb. (No. 1214) ; Siberia.— Colymbetes co.stulatus, Motsch. (No. 1218) ; Siberia.— Colymbetes dilatatus, Brulle (No. 1220) ? No. 670 var.? Europe. —Colymbetes discolor, Harr. (1222); North America. — -Colymbetes fossigei-, Motsch. (No. 1227); North America. — Colymbetes phseoptenis, Kirb. (No. 1243) ?=No. 1222; North America. — Colymbetes ruficeps, Men. (No. 1246); Caucasus. — Colymbetes sobrinus, Motsch. (No. 1249); North America.— Colymbetes subquadratus, Motsch. (No. 1253); Siberia. — Gaurodytes angusticollis, Sahl. (No. 1297); Lapland. — Gaurodytes leptapsis, Lee. (No. 1298); North America. — Gaurodytes longulus (No. 1299); North America. — Gaurodytes lutosus, Crotch. (No. 1300); North America. — Gaurodytes obovatus, Sahl. (No. 1301) ; Lapland. — Gaurodytes obscuripennis, Sahl. (No. 1302) ; Lapland. — Gaurodjiies ovalis, Sahl. (No. 1303); Gothland. — Gaurodytes suturalis, Crotch. (No. 1304); North America. The systematic position of the following is more doublful, but may possibly be with Agabus : — Agabus dilatatus, Sol. (No. 1183); Chili. — Agabus eminens, Kirsch. (No. 1184); Peru. — Anisomera bistriata, 3 s 2 494 On Aquatic Carnivorous Coleoptera or Dytiscidce. Group 1. Outline of thorax very discontinuous icith elytra; jirosternum but little thickened in the middle in front ; swimming legs elongate and slendei", their femora feeble, with rounded postero-external angle ; metasternal cavity ill-developed. Six species, from both Old and New Worlds. 662. Agabus (Anisomern) cordatus, 'Lec.jAnisomera cordata, M. C. — Suboblongus, depressus, niger, supra senescens, capite rufescente, anteuuis tarsisque 4 anterioribus geniculisque rufis ; prothorace transverso, basi fere truncato, elytris angustiore, lateribus sinuatis, anterius rotundati?, angulis posterioribus rectis. Long. 11, lat. 5 m.m. This species is very readily recognized by the form of the thorax. The legs are slender, and the claws elongate ; the sculpture is that of the Agabus guttatus allies. I have seen but a single individual which is a male, and has the three basal joints of the front and middle tarsi a little thickened, and furnished beneath with glandular hairs. North America, (Kansas). 720. 663. Agabus cephalotes, Reiche, M.C. — Fere oblongus, depressus, nigro-piceus, nitidus, antennis pedibusque rufis, prothoracis lateribus dilutioribus ; prothorace elytris angustiore, lateribus antrorsuui subrotundatis, posterius leviter angustatis, angulis posteiioribus paulo obtusis ; superficie baud coriaceo ; elytris punctis magnis posterius irregularibus, antrorsum in seriebus tribus ductis. Long. 9i, lat. 41 m.m. The shining surface and peculiar form of this species render its recognition very -easy. There is no difference of sculpture in the sexes ; in the male the two basal joints of the front and middle tarsi are scarcely thickened, but are furnished beneath with glandular hairs. Corsica. 721. 664. Agabus caraboides, n. sp. — Fern., Ovalis, fere depressus, niger, antennis pedi- busque concoloribus,elytrisfuscis; prothorace basi quam elytris evidenter angustiore, Brulle (No. 1207); Chili. — Colymbetesannulatus, Zoiil>. (No. 1212); Turconiania. — Colymbetes bicolor, Kirh. (No. 121.5); North America. — Colymbetes impressns, Zoub. (No. 123I); Tiircomania. — Colymbetes latus, Gebl. (No. 1236) ; Siberia. The position of the following species is quite doubtful : — Agabus hydroporoides, Murr. (No. 1191) ; West Africa. On Aquatic Carnivorous Coleoptera or DytiscidcB. 495 lateribus subrectis, auterius aug'ustato, basi rotuudato, angulis posterioribus obtusis ; ■elytris subopacis, coi'iaceis, punctis obsoletis. Long. 11t, lat. 5f m.m. Tbis is another very distinct species of which I have seen but a single individual, a female. The upper surface including the head and thorax is densely coriaceous. The dai-k colour of the legs and antenna?, and the absence of pale spots on the vertex are also important characters. Found by Dr. Milliugen either iu Syria or Mesopotamia. 722. 665. Agabus abnormicoUis, Ballion, Bull. Mosc. XLIII, p. 329. — Oblongo-ovalis, iiiger, nitidus, sublajvigatus, elytris pone medium guttula testacea, antennis rufis, pedibus piceis ; prothorace elytris evidenter angustiore, lateribus subrectis, angulis posterioribus obtusis. Long. 9^, lat. 5 m.m. . This species has the elytra considerably broader than they are in Agabus ■cephalotes. I have only the male before me, the basal joints of the front and middle tarsi, are slightly incrassate and furnished beneatli with glandular hairs, the claws are quite simple. Turkestan. 768. Q)C)G. Agabus maderensis, Woll., M.C. — Oblongo-ovalis, subtilissime reticulato- ■punctatus, piceus, supra fusco-brunneus, anteauis pedibusque rufis ; prothoracis lateribus subrectis, angulis posterioribus rectis ; elytris seriebus minus regularibus punctorum numerosorura. Long. 8, lat. 4 m.m. This species alUed to Dytiscus guttatus (No. 670) is smaller, and is readily distinguished by the much more numerous punctures on the elytra. The male is more shining than the female, and the reticulation of the elytra is excessively indistinct in it. The basal joints of the front and middle tarsi are but little incrassate, and the anterior claw of the front ones is nearly simple, being slightly- thickened, and with its lower edge a little sinuate. Madeira. 723. Gu7. Agabus {(Jaurodi/tes) intersectus, Crotch, Tr. An]. Ent. Soc. IV, p. 419. — Oblongo-ovalis, anterius angustulus, niger, supra aenescens, nitidus, antennis rubs, pedibus piceis ; prothorace basi elytris angustioi'o, lateribus leviter obliquis, lenissime curvatis, angulis posterioribus rectis ; elytris densissime sat fortiter icticulatis. Long. 8, lat. 4 m.m. I have seen only one female of this species ; Crotch says the male has the anterior, <;law of the front tarsi dentate. North America, (Nevada). 736. 496 On Aquatic Carnivorous Coleoptera or Dytiscidce. Group 2. Outline ofthorax either slightly discontinuous, or continuous with thatofthe elytra; prosternal process comparatively broad, nearly flat, evenly and distinctly margined, shining and impunctate; metasternal groove moderately broad. Hind coxfe never large ; wings of metasternum large ; coxal lines deeply impressed in their upper part, much prolonged in the anterior and outward direction; hind legs slender or moderate (never stout), their femora little thickened, the postero-external angle slightly obtuse, sometimes rectangular. Male fore feet but little developed, clothed beneath with very short "glandular" pubescence ; sexual ditterences of sculpture slight. Seventeen species from both Old and New Worlds. 668. Agabus hypomelas, Mann., M.C. — Oblongo-ovalis, niger, nitidus, antennis pedibusque rufis, supra sat conspicue tenescens, capite anterius, prothoracis lateribus versus angulum anteriorem, elytrorumque epipleuris vage rufescentibus ; elytris dense subtilissime reticulatis subtiliusque punctulatis; metasterni impressione brevi. Long. 8, lat. 4^ m.m. In this species the lateral margin of the thorax is rather fine, and the thorax is rather straight sided, the hind angles being nearly rectangular. The male has the three basal joints of the front and middle tarsi slightly thickened, and turnished beneath with short glandular hairs. The exact position of this species is not easy to define, the prosternal process is short and broad, but is very feebly punctulate at the sides, the metasternal cavity is unusually short, and the coxal lines are not greatly divergent in their upper part ; the side wings of the metasternum are shorter than in Dytiscus guttatus (No. 670). North America, (Sitkha, Vancouver's Island). 737. 669. Agabus styriacus, n. sp. — Oblongo-ovalis, latiuscalus, parum nitidus, niger, supra subaeuescens, antennis palpisque rutis, pedibus piceis, tarsis rufis, elytris guttis duabus testaceis ; prothorace lateribus obliquis, basi quam apice latiore, angulis posterioribus rectis ; elytris undique punctato-rugosulis. Long. 81, lat. 4| m.m. The surface of the wing-cases in this species, is rendered rough by a dense, fine, indefinite sculpture which can scarcely be called punctuation ; in the male, even, on the base of the elytra with a high magnifying power, this sculpture does not assume the form of reticulation, but in the female the sculpture is rather coarser and deeper, and gives the appearance of very obscure reticulation and dense rugulosities combined. In the male the three basal joints of the front tarsi are On Aquatic Carnivorous Coleoptera, or Dijtiscidce. 497 much incrassate and fiirnisbed beneath with very short glandular hairs ; the middle tarsi are not so much incrassate as the front ones. This species is allied to Dytiscus guttatus, and some of the extreme varieties of that species approach considerably to it, but it appears to me really distinct. It is broader, and tlie peculiar sculpture is much more developed than in the most extreme varieties of D. guttatus ; the prosternal process is broader, and the basal joints of the front tarsi of the male are more incrassate. Stvria, (Herr Tschapek). 1166. 670. Dytiscus guttatus, V-e^y^.. Agahus guttatu.'^, M.C. — Oblongo-ovalis, niger, nitidus, antennis, palpis pedibusque rufis, elytris gnttis duabus parum distinctis testaceis ; prothorace lateribus subrectis, basi quam apice paulo latiore, basi utrinque fere recto, angulis posterioribus rectis, raargine lateral! crasso ; elytris versus apicem fere opacis et rugulosis, anterius nitidis. Long. 8, lat. 4 m.m. In the female the elytra near the base are finely but quite distinctly reticulate or coriaceous, in the male this reticulation is less distinct, and the surface near the base has almost the appearance of being finely and closely punctulate ; in each sex the roughening of the surface at the extremity is greater than in the allied species. In the male the basal joint of the front and middle tarsi is a good deal incrassate, and the two following joints are a little so, and the three joints are clothed beneath with very short glandular hairs. The two claws of the front feet are similar and simple. The species varies in the colour of the legs, these being sometimes piceous, and the sculpture also shows some curious variations. Europe, (Sweden ; Finland, to 68* 20' North, Sahlberg ; Britain, France, Germany, Nortliern Italy). 724. (J71. Agabus armeniacus, n. sp. — S Oblongo-ovalis, niger, nitidus, antennis palpis pedibusque rufis, elytris guttis duabus parum distinctis testaceis; prothorace lateribus fere subrectis, basi quam apice paulo latiore, basi utrinque levitei- obliquo, angulis posterioribus obtuse rectis, margine lateral! crasso ; elytris versus apicem subopacis, anterius nitidis et leevigatis. Long. 9, lat. 41 m.m. Extremely closely allied to Dytiscus guttatus (No. 670), but with the base of the thorax not quite so straight, so that the hind angles are slightly more obtuse, and with the elytra (in the male at any rate) smoother, as in Dytiscus biguttatus (No. 676). The tarsi of the male are formed as in D. guttatus, but the front claw on the anterior is thicker than the other claw. The female I have not seen. Trebizond, Daghestan. 725. 498 On Aquatic Carnivorovs Coleoptcra or DytiscidcB, 672. Agabus americanus, Aub^, M.C.-— Oblongo-ovalis, nigricans, nitidiis, antennis palpisque rufis, pedibus anterioribus rufo-piceis, posterioribus fere nigris ; prothorace lateribus subrectis, angulis posterioribus obtusis, rotundatis, margine laterali elevate; elytris nullo mode reticulatis, laevigatis, punctis subseriatis conspicuis. Long. 8i, lat. 4 m.m. The male has the basal joints of the front tarsi a good deal incrassate, and much compressed, and rather extensively furnished beneath with short glandular pubescence ; the anterior claws are rather elongate and sinuate. The terminal joint of tlie middle tarsi is elongate and slender. I have seen only Aube's type of this species, which appears to be a very distinct one, by the smooth shining surface, and the indistinct rounded hind angles of the thorax. Mexico, (coll. Mnizech). 11.54. 673. Colymbetes seriatus. Say, Agabus seriatus, M.C. — Oblongo-ovalis, niger, supra senescens, nitidus, antennis palpisque rufis, pedibus piceis ; prothorace lateribus obliquis, basi subtruncato, angulis posterioribus rectis ; elytris subtilius reticulatis, versus apicem evidentius reticulatis, sed neque opacis nee rugosis. Long. 9, lat. 4f m.m. This species is closely allied to Dytiscus guttatus (No. 670), but is rather larger, and has the sculpture of the upper surface finer, and similar in both sexes ; the prosternal process is larger and more acutely pointed at its apex. The male has the three basal joints of the front and middle tarsi a little thickened and furnished beneath with glandular hairs ; the anterior claw of the front feet is a little dilated near the base so that its lower edge is slightly sinuate. The species seems to be widely distributed in North America and is somewhat variable in form and sculpture. North America. (Canada, California). 727. 674. Agabus perplexus, n. sp. — Oblongo-ovalis, niger, supra aenescens, antennis pedibusque piceis ; prothorace brevi antrorsum angustato, angiilis posterioribus sub- rectis ; elytris dense subtiliter reticulatis, retis versus apicem baud omnino minutis. Long. 9, lat. 5t m.m. In the male the basal joints of the front and middle tarsi are distinctly thickened and furnished beneath with glandular hairs ; the anterior claw of the front feet has the basal portion slightly thickened, so as to cause the outline beneath to be slightly sinuate. 1 he species is closely allied to Colymbetes seriatu.s, but the lateral portions of the metasternum are not quite so much reduced in size. North America, (California, Vancouver's Island). On Aquatic Carnivorous Coleoptera or DytiscidcB. 499 675. Agabus lugens, Lee, M.C. — Ovalis, latiusculus, niger, supra subaenescens, omnium densissime reticulatus, subnitidus, aateunis palpis pedibusque piceis, elytris versus latera gutta elongata, subdistincta, testacea ; prothoraoe brevi basi elytrorum latitudine, lateribus obliquis, angulis posterioribus fere rectis. Long. 9i, lat. 5i m.m. In the male the front and middle tarsi have the three basal joints distinctly thickened and furnished beneath with glandular hairs ; the claws are simple. The species is very closely allied to Agabus perplexus, but the reticulation of the elytra is so dense and indistinct that, even towards the apex, distinct meshes can scarcely be perceived. North America, (California, Vancouver's Island). 729. 676. Dytiscus biguttatus, 01., Agahus hignttatus, M.C. — Oblongo-ovalis, niger, nitidus, antennis rufis, apice summo soepius nigro, palpis piceo-rufis ; elytris guttis duabus testaceis ; prothorace basi curvato, lateribus plus miuusve curvatis et antrorsum angustatis, margine lateral! baud crasso ; elytris ad basin et ad suturam vel omnino Isevigatis, vel omnium subtilissime reticulatis, versus apicem subtiliter vel vix conspicue rugulosis et paulo conspicuius reticulatis. Long. 9, lat, 45 m.m. In the male the three basal joints of the front and middle tarsi are distinctly incrassate and furnished beneath with glandular hairs, and the anterior claw of the front foot has a tooth or lobe in the middle beneath. There is a sexual difference in sculpture the female being a little less shining, and less indistinctly reticulate than the male. This is a very widely distributed and one of the most variable species, and the variations seem to be, to a greater or less extent, geographical. The elytra, in the South-east of Europe and Asia Minor, are frequently more or less red. The largest, broadest and most smooth individuals occur in Southern Europe. The variety from the Canary Islands (A. consanguineus, Woll.) has the reticulation of the upper surface more distinct, and the antennae immaculate at the apex, the legs and palpi of rather more dilute colour. The species in Scotland makes a nearer approach in form and sculpture to Dytiscus guttatus (No. 670) than it does elsewhere, and this form is approximated by mountain specimens even from the South of Europe. The tooth on the front claw of the male varies much, being^sometimes quite slender, and in other cases a broad lobe. Central and Soutliern Europe, North Africa, Western and Central Asia. (Scotland, England ; Belgium, Alsatia, France, Spain, Sierra Nevada 7,000 feet ; Italy, Sicily, Greece ; Canary Islands ; Algeria, Egypt, Nubia, Siaai ; Hedjaz ; Trebizond ; TurkLstiu, Dras, Kargil and Leh, F. Stoliczka, September 9th, 1873). 731. 677. Agabus heydeni, Wehncke, Berl. Enb. Zeit. XVI, p. 134. — Ovalis, politus, nitidus, niger, antennis palpisque rufis, pedibus piceo-rufis : elytris pone medium TRANS. ROy. DUU. SOC, N.S., VOL. II. 3 T 500 On Aquatic Carnivorous Coleoptera or Dytiscida. minus distincte pallido-iiotatis, prothorace lateribus sat crasse marginatis, vix per- spicue curvatis, autrorsum sat angustatis, angulis posterioribus rectis. Long. 8, lat. 4 m.m. The male has the basal joints of the front and middle tarsi very slightly incras- sate, the basal two being furnished beneath with short glandular hairs, the claws are quite simple. Although the surface looks very polished, there is a very obsolete reticulation of the elytra, and this is a little more conspicuous in the female than it is in the male. Though allied to Dytiscus biguttatus, this species is much smaller, and the hind tarsi are not quite so elongate and slender. Europe, (Spain and Portugal). 732. 678. Agabus binotatus, Aub^ M.C. — Oblongo-ovalis, nitidus, Isevigatus, niger, antennis rufis ; elytris rufis, fusco-suffusis, limbo dilutiore, pone medium macula plus minusve distincta pallida, prothoracis lateribus rufis, pedibus piceis; prothorace crasse marginato, lateribus leviter curvatis, angulis posterioribus fere rectis, vix obtusis. Long. 81, lat. 4 m.m. The male has the basal joints of the front and middle tarsi slightly thickened, the first and second being also clothed beneath with short glandular hairs. Europe, (Corsica, Sardinia). 733. 679. Agabus castaneus, n. sp. — Ovalis, nitidus, Isevigatus, subtus niger, supra castaneus, antennis palpis pedibusque rufis, femoribus piceis ; prothorace antrorsum angustato, lateribus obliquis baud curvatis, angulis posterioribus fere rectis, vix acutis, margine laterali sat crasso. Long. 8, lat. 4i m.m. The male has the basal joints of the front and middle tarsi a little thickened, and the first and second furnished beneath with short glandular hairs: the female is unknown to me. Syria, (Mount Sannin). 734. 680. Dytiscus paludosus, Fab., Agabus paludosus, M.C. — Ovalis, sat convexus, Isevis, nitidus, niger, capite anterius prothoracis lateribus elytrisque rufescentibus, antennis pedibusque anterioribus rufis, femoribus medio picescentibus, pedibus posterioribus piceis. Long. 7, lat. 4 m.m. In this species the hind angles of the thorax are about rectangular, and the out- line of the elytra is but little discontinuous with that of the thorax. The upper surface is very smooth and shining, and there is no sexual disparity of sculpture, The male has the front and middle tarsi with the basal joints a little incrassate and furnished beneath with moderately short glandular hairs. Europe, (Sweden; Finland to 62", SahlLerg; Britain; France; Spain; Germany). 735. On Aquatic Carnivorous Coleoptera or Dytiscidce. 501 681. Agabus japonicus, Sharp, Tr. Ent. Soc. Loncl. 1873, p. 50. — Ovalis, sat convexus, Isevis, nitidus, niger, capite thoraceque vix subsenescentibus, elytris fuscis, basi humerisque vage rufescentibus, antennis tilnisque quatuor anterioribus, femoribus pedibusque posterioribus piceis. Long. 7, lat. 41 in.m. The male has only an extremely slight incrassation of the front and middle tarsi, and only a very narrow space on their underside clothed with glandular hairs ; and the claws are simple. The species much resembles Dytiscus paludosus, but is rather broader, more oval, and the elytra and the thorax have their outline very continuous: and the serial punctures of the elytra are finer. Japan ; North C'liina. 780. 682. Agabus sequalis, n. sp. — Ovalis, sat convexus, fere laevigatus, sat nitidus, niger, capite thoraceque vix subsenescentibus, hoc ad latera indeterminate rufes- ceute, elytris fuscis, basi margineque externo testaceis, antennis pedibusque testaceis : elytris neque punctulatis, nee reticulatis. Long. 7, lat. 4 m.m. The male has the front and middle tarsi distinctly incrassate and furnished beneath with short hairs, which bear minute palettes, the front claws are quite simple and not elongate ; the hind tarsi have the two basal joints provided beneath with swimming hairs. The female I have not seen. This species is very similar to Dytiscus paludosus (No. 680), but the colour is a little more obscure, and the upper surface less shining, and the serial punctures of the elytra are finer : the thorax is shorter behind the eyes, and its outline more continuous with the elytra, and the legs are of a paler colour. It is also excessively similar to Agabus japonicus, but the upper surface is less shining, the legs are paler in colour, the male tarsi are more incrassate, and the anterior border of the hind coxa is more arched so that the side wings of the metasternum are externally more abbreviate. Eastern Siberia, (Transbaikal). 781. 683. Agabus raffrayi, n. sp. — Ovalis, sat convexus, laevis, nitidus, niger, capite anterius prothoracisque lateribus baud late rufescentibus, elytris fusco-rufis, basi lateribusque dilutioribus, antennis tibiisque quatuor anterioribus rufis, femoribus pedibusque posterioribus piceis. Long. 7h, lal. 4 m.m. The male has the basal joints of the front and middle tarsi a little incrassate, and furnished beneath with short hairs which bear minute palettes, the claws are simple : I think the two basal joints of the hind tarsus are provided beneath with swimming hairs. The species is excessively similar to Dytiscus paludosus (No. 680), but is slightly 3 T 2 502 On Aquatic Carnivorous Coleoptcra or DytiscidcB. broader and more oval in outline, and the hind legs are decidedly more developed for swimminsr, being: shorter and stouter. Abyssinia, (found by Raflfray). 782. 684. Agabus marginalis, n. sp. — Ovalis, sat convexus, laevis, iiitidus, niger, capite anterius prothoraceque lateribus rufescentibus, elytris fusco-rufis, basi lateri- busque dilutioribus, antcnnis tibiisque anterioribus rufis, femoribus pedibusque posterioril)us jnceis. Long. Zi, lat. 4i ni.m. fn this species the prosternal process is rather peculiar ; the space separating the fi-ont legs is broad, but the prosternal process is not very much dilated behind, so that it is not greatly wider than the .space between the coxse, it is a little elevated along the middle, and i« finely punctured at the sides. The species greatly resembles Dytiscus paludosus (No. 680), but is larger, has the lateral margin of the thorax finer, and the hind legs shorter and stouter ; in some respects it approximates to Dyti-cus brunneus (No. 688), and may be considered intermediate between it and D. palu- dosus, but it is not so broad and is differently coloured and has the prosternal process very different. I have seen only the female. Europe. (Greece, Styria). 78.3. Group 3. Outline of thorax and elytra continuous ; 2^''ostcrnal iJrocess very broad and fiat, polished : middle coxce rather widely separated, with highly developed metasternal impression ; hind coxse rather well developed, the wings of the metasternum rather short ; swimming legs moderately slender. Three species from the New World. 685. Colymbetes obtusatus. Say, Agabus obtusatus, M.C. — Ovalis, baud convexus, pernitidus, niger, antennis pedibu.sque rufis, femoribus plus minusve picescentibus, elytris pone medium versus latera lineola, et ante apicem gutta, testaceis ; supra undique conspicue sed baud profunde reticulatus, reticulis magnis ; prothoracis margine laterali nuUo modo crasso. Long. 8, lat. 4l m.m. The male has the basal joints of the front and middle tarsi a little incrassate, and furnished beneath with short hairs which bear quite distinct palettes : the claws of the front feet are very nearly sim^jle, and are scarcely more developed than in the female. On Aquatic Carnivorous Coleoi^tera or DytiscidcE. 503 The shining surface and large meshes of the reticulation are very characteristic ; when a careful examination is made, it is seen that in the middle of these meshes (not on the lines thereof as in most other species), there are excessively minute punctures. Colymbetes nitidus, Say. (Tr. Am. Phil. Soc. II. p. 98) is referred to this species on the authority of Crotch. North America, (Massachusetts). 788. 686. Agabusplanatus,n.sp. — Fern. Ovalis,haud convexus, pernitidus, nigro-piceus, colore subtus paulo dilutiore, antennis pedibusque rufis, elytiis pone medium versus latera lineola, et ante apicem gutta testaceis ; supra undique conspicue reticulatus, reticulis magnis ; jjrothorace margine laterali crasso. Long. 9, lat. 5 m.m. I have seen but a single individual (?) of this species, which seems to be very closely allied to Agabus obtusatus, but is a good deal larger, and has a much broader lateral margin to the pronotum. This is perhaps the insect considered by Ci'otch (Tr. Am. Ent Soc, 1873. p. 417), to be a female variety of Agabus semivittatus, Lee. North America. 781). 687. Agabus brevicollis, Lee, M.C. — Late ovalis, subdepressus, vix nitidus, niger, antennis rufis, pedibus piceis ; elytris densius profunde reticulatis, pone medium versus latera guttula ferruginea. Long. \Q\, lat. 6l m.m. I have seen but a single individual, a male in very decayed condition, of this very distinct species ; it is of a very broad flat form, with the thorax continuing the outline of the elytra with very little interruption, the lateral margin of the thorax is broad and but little raised ; this male has the front and middle tarsi moderately incrassate and furnished beneath with glandular hairs, the claws are broken. North America, (California). 802. Group 4. The single (European) species forming this group has the characters similar to those of the highly developed members of group 2, except that the swimming legs are highly developed, being short and thick. G8S. Dytiscus brunneus. Fab., Agnhus hninneus, M.C — Ovalis, latiusculus, sat convexus, nitidus, Isevis, subtus niger, capite prosternoque ferrugineis, medio nigris. 604 On Aquatic Carnivorous Coleoptera or DytiscidoB. Bupra castaneus, antennis tibiisque anterioribus rufis, femoribus medio pedibusque posterioribus piceis. Long. 9, lat. 5i m.m. Tlie front and middle tarsi are not very greatly thicker in the male than in the female, but they are furnished beneath in the former sex with elongate glandular haira, and in the same sex there are three joints of the posterior tarsus provided beneath with swimming hairs. The species is readily distinguished by the broad form, smooth shining surface unicolorous above, and by its stout legs. The prothorax is large and continuous in outline with the elytra. Central and Southern Europe, Corsica, Sardinia, Noi-thern Africa ; (South of England ; Alsatia ; France, basin of the Seine ; Pyrenees, Spain, Poi-tugal, Italy, Tangier). 784. Group 5. Prosternal process broad and polished ; its margin just behind the coxce very broad and dilated, in the posterior half excessively fine. Three New World species. 689. Colymbetes stagninus, Say, Agnbus stagninus, M.C. — Ovalis, minus con- vexus, niger, antennis rufis, pedibus piceis, elj^tris ante apicem vitta sublaterali elongata testacea ; vel nitidus (cj) densiusque punctato-reticulatus, vel subnitidus {$) densiusque minus obsolete reticulatus ; prothorace magno. Long. 10, lat. bh m.m. The male has the front and middle tarsi a good deal incrassate, and amply pro- vided beneath with rather long hairs which bear distinct palettes, the claws of the front feet are moderately long, and the anterior one has the base much dilated, the posterior is rather longer than tlie anterior one, and has the base abruptly thickened in a similar manner ; the terminal joints of the middle tarsi in this sex are unusually elongate. The distinction in the sculpture of the sexes is very marked. North America. (Pennsylvania). 785. G90. Agabus semivittatus, Lee, M.C. — S Ovalis, convexus, nitidus, niger, antennis rufis, pedibus obscure rufis, elytris ante apicem vitta sublaterali elongata testacea sat distincta ; elytris subtilissime punctulatis baud perspicue reticulatis ; prothorace magno. Long. 9, lat. b\ m.m. The male has the front and middle tarsi a good deal incrassate, and amply pro- vided beneath with rather long hairs which bear distinct palettes ; the claws of the 071 Aquatic Carnivorous Coleoptera or Dytiscidce. 505 front feet are rather short, the anterior is rather stout and is abruptly bent, and is furnished with a very large basal lobe, the hind claw is stout and without noticeable lobe ; the middle tarsi have the apical joints a little elongated. The female is unknown to me. The species is readily distinguished from Colyrabetes stagninus by the smaller size and more convex form, and by the more arched anterior border of the hind coxae causing the side wing of the metasternum to be much more linear, as well as by numerous other differences. The mutilated ). The difference in the appearance of the two sexes is very striking. The male has the basal joints of the front and middle tarsi a good deal thickened, and furnished beneath with moderately long and glandular hairs ; the TBANS. BOY. DUB. SOC, M.S., VOL. U. » U 508 On Aquatic Carnivoroxts Coleoptera or DijtiscidcB. claws of the front feet are short, and the anterior is dilated beneath by a tooth occupying the greater part of its length but having a sharp extremity. The specimen of Agabus punctulatus extant in Dejean's collection is a rufescent variety of this species. North America, (Pennsylvania, Newfoundland, sec. Crotch). 756. Group 8. Form narrow and parallel ; males with short anterior claws dentate beneath, and with a series of stricB forming a Jile{no doubt a stridulating organ) on each sideofthe third ventral segment ; prosternal process rather narrow, very little compressed, nearly glabrous or feebly punctulate ; anterior border of hind coxse much arched, wings of the metasternum moderately large ; hind tarsi rather feeble, but the femora have a distinct lamina at the postero-external angle, the cilire at this spot very rudimentary. Four species from both Old and New Worlds. 697. Agabus {Gaurodytes) , biguttulus, Th. 8k. Col. IX, p. 110. — Oblongo-ovalis, niger, nitidus, supra subaiuescens, antennis pedibusque rufis, femoribus picescentibus; supra vel subtilius sed baud inconspicue (c?) vel ubique evidenter (?) reticulatus : elytris punctis subseriatis baud profundis. Long. 6t, lat. 3| m.m. This species is very similar at first sight to Dytiscus affinis (No. 698), but the serial punctures of the elytra are not so deep. There is considerable difference in the sculpture of the sexes ; in the male the reticulation of the elytra is not much more distinct than in .4gabus aeneolus, while in the female this sculpture is much more marked, the rather large meshes of the reticulation do not however cause the surface to be dull in this sex ; the male has the basal joints of the front and middle tarsi distinctly thickened and furnished beneath with short hairs which bear distinct palettes ; the claws of the front feet are short, and the anterior one bears beneath a sharp tooth near the base. The elytra have sometimes two pale spots like A. aeneolus (No. 696), but sometimes these cannot be distinguished. Gaurodytes boreellus, Sahl. (Not. fenn. XI, p. 409) is I consider a variety of this species. North Europe, (Sweden, and Finland to 68°, according to Sahlberg). 755. 698. Dytiscus affinis, Payk., Agabus affinis, M.C. — Oblongo-ovaHs, niger, vix supra subsenescens, antennis pedibusque rufis, femoribus picescentibus ; sublsevigatu.s, elytris guttula pone medium maculaque apicali pallidis. Long. 6i, lat. 3i m.m. On Aquatic Carnivorous Coleoptera or Dytiscidcr. 509 The three basal joints of the front and middle tarsi are very little incrassate, and are furnished beneath with short hairs, bearing very small and indistinct palettes, the claws of the front feet are not elongate, and the anterior one has near the base a sharp prominent tooth : the ditFerence in sculpture of the two sexes is extremely sliglit. The pale marks on the elytra are sometimes not easily detected. Northern Europe, and Siberia ; (Sweden ; Finland to 08°, according to Sahlberg ; Britain, Northern France ; Germany). 754. 699. Agabus stridulator, n. sp. — Oblongo-ovalis, nitidus, niger, vix supra sub- senescens, antennis pedibusque rufis, femoribus picescentibus ; supra Isevigatus, nullo modo reticulatus. Long. 6, lat. 3i m.m. The basal joints of the front tarsi in the male are almost without incrassation, and their clothing beneath is but little developed : the front claws are short, and the anterior one bears beneath a sharp prominent tooth. There seems to be no sexual difference in the sculpture of the upper surface ; but on the undersurface the file on each side of the third ventral segment of the male is very distinct. The species is extremely closely allied to Dytiscus affinis, but is rather less elongate, and its surface is destitute of the very rudimentary reticulation which on careful examination may be detected in that species : the anterior tarsi of the male have the basal joints less incrassate, the prosternal process is narrower; and the hind coxsa are just slightly smaller, so that the wings of the metasternum are just appreciably less reduced. As in D. affinis a pale dash may sometimes be seen near the side of each elytron about the middle, and another near the apex. North America, (Hudson's Bay, Canada). 1156. 700. Agabus {Eriglenus) unguicularis, Th. Sk. Col. IX, p. 101. — Ovalis, sat convexus, niger, vix supra subsenescens, antennis pedibusque ruiis, femoribus picescentibus subtilissime reticulatus, nitidus, elytris guttula pone medium maculaque apicali pallidis ; elytris punctis subseriatis et apicalibus haud profundis, epipleuris basi rufescentibus. Long. 6i, lat. 3i m.m. There is no difference in the sculjiture of the sexes in this species : the male has the basal joints of the front and middle tarsi a little incrassate, and furnished beneath with short hairs bearing very small palettes ; the claws of the front feet are short, and the anterior bears a very sharp tooth in the middle beneath. Europe, (Sweden, South Finland, Stettin, Berlin, Britain). 757. s u > .''10 On Aquatic Carnivorous Coleoptera or Dytiscidce. Group 9. Hind coxae moderate or rather large, wings of metasternum moderate ; prosternal process acuminate, compressed, finely margined ; swimming legs moderately stout ; middle claws of front feet rather long ; elytra marked with yellow. Five species from both Old and New Worlds. 701. Colymbetes t?eniolatus, Harris, Agahus taeniolalus, M.C. — Ovalis, sat con- vexus, nitidus, rufus, vertice et prothorace anterius et posterius senescentibus, elytris testaceis, lineis longitudinalibus latis plus minusve confluentibus seneis ; supra fere laevigatas. Long. 9, lat. 4| m.m. The male has the basal joints of the front tarsi (especially the first one), a little thickened, and furnished beneath with rather short hairs which bear small palettes, the claws are somewhat elongate and the anterior one has a small tooth near the base ; the middle tarsi are scarcely thickened but the basal joint is extremely elongate, its length considerably exceeding that of the longest of the two apical tibial spurs ; the intermediate tibiae have their inner edge much emarginate. North America, (Peimsylvaiii;i). 761. 702. Agabus {Gaurodytes) disintegratus. Crotch, Tr. Am. Ent. Soc. IV, p 416. — Ovalis sat convexus, nitidus, rufus, pectore coxisque posterioribus nigricantibus, vertice et prothorace anterius et posterius aenescentibus, elytris testaceis, lineis longitudinalibus vel discretis vel confluentibus aeneis ; supra fere laevigatus. Long. 8i, lat. 4t m.m. The male has the basal joints of the front and middle tarsi a little thickened, and furnished beneath with rather short hairs which bear small jsalettes; the claws of the front feet are somewhat elongate and the anterior one has a small tooth near the base ; the basal joint of the middle tarsus is somewhat elongate, shghtly exceeding in length the tibial spurs ; the tibiae are quite simple. The species is readily distinguished from Colymbetes taeniolatus, by the undersur- face being more or less black, and by the different intermediate legs in the male, and it also has the side wings of the metasternum rather larger. The specimens before me show considerable variation in size and form and markings, and even in some of the structural characters ; the material before me does not enable me to feel certain whether all should be referred to one species or not ; but I am inclined to think this is a species forming more or less localized varieties. North America. (Kansas, Ai-izona, Pennsylvania. Nebraska, Canada; sec. Crotch). 762. 0)1 Aquatic Carnivorous Coleoptera or Dytmcidce. 511 703. Agabus liueellus, Lee, M.C. — " Regulariter ovalis, piceo-ferrugineus, nitidus subtilissime reticulatus, elytris testaceis, sutura et vittis utrinque quatuor angustis, nigris antice abbreviatis, nebulisque exterius piceis ornatis, sternis piceis." Long. 7x, lat. 4 m.m. I have seen only a single very immature female that I can refer to this species, the reticulation of the elytra is much more distinct than itis in Colymbetes tseniolatus, and the mesosternal groove is excessively indistinct being very narrow, and obliquely perpendicular in its direction, the prosternal process short, and with the sides much compressed. North America, (California). 763. 704. Agabus lineatus, Gebl., M.C. — Ovalis, brevis et latiusculus, sat convexus, testaceus, pectore coxisque posterioribus obscuris; elytris subtiliter sed baud obsolete reticulatis, lineis 5 elongatis suturaque nigris. Long. 64, lat. 4 m.m. Of this species I have seen only a single immature female individual : it seems very closely allied to Agabus lineellus but is shorter, and the hind coxas are shorter ; the prosternal process and mesosternal grooves are similar except that the latter is more horizontal (less oblique). Siberia. 7G4. 705. Dytiscus didymus, 01., Agabus didymus, M.C. — Ovalis, sat convexus, sat nitidus, robustus, niger, supra ajnescens, prothoracis lateribus elytrorumque epipleuris ferrugineis, elytris macula didyraa pone medium versus latera, aliaque rotundata apicali pallidis, antennis testaceis, pedibus piceo-rufis ; supra sublsevigatus, elytris subsericantibus, obsoletissime punctulatis ; prothorace basi utrinque versus angulos posteriores leviter sinuato, his subrectis. Long. 8, lat. 4| m.m. The male has the front and middle tarsi distinctly incrassate, and furnished beneath with rather long hairs, bearing small palettes ; the claws scarcely differ from those of the female. The species is very readily distinguished by the peculiar Dale mark near the side of the elytra, which in clean specimens is always conspicuous, and is formed by two small spots nearly or altogether coalesced. Central and Southern Europe, and Algeria, (England, France, Germany, Spain, Tangier). 769. 512 On Aquatic Carnivorous Coleoptera or Dytiscidce. Group 10. Anterior tarsi of male never greatly incrassate, their claws more or less elongate, their undersurface bearing distinct, but not large, palettes. Prosternal process elongate, never broad, but little compressed and not carinate ; metasternal groove rather long ; wings of metasternum rather large ; hind coxae moderately developed, their front border not much arched ; swimming legs moderately slender. Twelve species from both Old and New Worlds. 706. Dytiscus congener, Payk., Agabus congener, M.C — Species variabilis; Ovalis, vel oblongo-ovalis, vix convexus, niger, elytris fuscescentibus, lateribus dilutioribus, prothorace vix senescente lateribus angustius minus discrete ferrugineis, margine laterali hand lato, antennis pedibusque rufis, his femoribus nigricantibus : prosterni processu elongato, angusto, acuminate, nitido, impunctato, leviter transversim convexo, baud carinato. Lonof. 7, lat. 4 m.m. The male has the front and middle tarsi rather elongate, their basal joints distinctly incrassate, and furnished beneath with rather short hairs which bear quite distinct palettes, tbe claws of the front feet are elongate and but little curved, and very nearly simple, there being a scarcely visible sinuation of their lower edge. In this sex the elytra bear only obscure traces of reticulation, while in the female the sculpture is excessively variable ; sometimes the wing-cases in this sex are as free from sculpture as in the male, while sometimes they are densely and distinctly reticulate so as to render the surface dull ; the species also varies in colour, size and form, and as the varieties are more or less localized in distribution thej^ lead one to believe at first that they may be distinct species. In Scotland the females are generally very dissimilar to the males, but one also finds rarely there specimens which are intermediate in colour and sculpture between the males and the dissimilar females. In Sweden, according to the few individuals I have seen from there, the females are but little different from the Scotch intermediate form. On Monte Viso, Ghiliani found a brightly coloured form looking just like Dytiscus paludosus, and having the females similar in colour and sc\ilpture to the males ; while Doria has found at Gnecco a large form in which the difierence between the sexes is carried to its extreme. In the variety Gaurodjtes thomsoni (Sahl. Not. Fenn. XI, p. 407) the form is usually narrower and more elongate, and the colour darker, and the females have a slight reticulation near the humeral portion of the elytra. None of the characters however are constant, and as the structural characters remain without variation, I have been compelled to consider all these forms as belonging to but On Aquatic Carnivorous Colecptera or Dytisciche. 513 one species. Gaurodytes coriaceus, Sahl., (Not. Fenn. XIV, p. 174) is also I think a variety of the female of this species. This appears to be an arctic, aljiine, and subalpine species. Europe, Siberia, Greenland, North America, (Sweden, Finland, Lapland, Britain, Germany, France, Northern Italy ; Labrador, Hudson's Bay, White Mountains). 744. 707. Agabus borealis, {dissimills, Said.), n. sp. — Oblongo-ovalis, hand convexus, Stubnitidus, niger, supra fusco-seneus, elytris versus latera j^allidioribus, antennis pedibusque rufis, illis fusco-maculatis, prothorace margine laterali tenuiore ; elytris sat nitidis (cj), vel fere opacis {$). Long 6i, lat. 3i m.m. This is probably another variety of Dytiscus congener, with which I have not however united it, as the males have the surface of the elytra rendered a little silky by an exce.ssively fine and indistinct sculpture. The male tarsi, and the other structural characters show no diflerence from D. congener. Arctic Siberia, (found by Dr. Sahlberg). 745. 708. Colymbetes ambiguus, Say, Agabus ambiguus, M.C. — Ovalis, vix convexus, niger, elytris rufescentibus, antennis pedibusque rufis, his femoribus nigricantibus, prothorace margine laterali baud lato ; prosterni processu elongato, angusto, acuminato, lateribus sat compressis, punctulatis. Long. 6|, lat. 3| m.m. I have seen but two specimens in bad condition, and find the only important difference from Dytiscus congener, to be the more carinate and less smooth prosternal process ; I have not seen the female : the male has the tarsi formed as in Dytiscus congener (No. 706) ; I shall not be surprised if the examination of other individuals, show this supposed species to be not distinct from Dytiscus congener. The identification with Say's description is by no means a certainty. A specimen was sent me by Leconte as being his A. morosus. North America, (California). 746. 709. Agabus mntus, n. sp. — Ovalis, parum convexus, nitidus, baud reticulatus, nigricans, elytrorum lateribus dilutioribus, prothorace subaenescente, antennis pedi- busque rufis. Long. 6i, lat. 3i m.m. The male has the basal joints of the front and middle tarsi scarcely incrassate, and. having therefore a very small area beneath furnished with sexual clothino- ; the front claws are a little longer than in the female, nearly straight, and a little in- crassate or laminate ; the female is rather duller than the male but has no reticulation. The species is closely allied to Dytiscus congener (No. 706), but is rather smaller 514 On Aquatic Carnivorous Coleoptera or Dytiscidm. and darker in colour, and the upper surface is still more destitute of reticulation, and the anterior tarsi of the male are more slender. A series of about twelve specimens shows very little variation. North America, (Hudson's Bay). 1155. 710. Agabus anthracinus, Mann., Bull. Mosc. 1852, II, p. 304. — Ovalis, parum latus, sat convexus, subnitidus, niger, .supra senescens, antennis pedibusque rufis, plus minusve infuscatis, his femoribus picescentibus ; supra undique crebrius pro- funde reticulatus, reticulis elytrorum (prsesertim versus apicem) fere transversis. Long. 7 2, lat. 4 m.m. The male has the basal joints of the front and middle tar.si, a good deal incrassate, but much compressed, and furnished beneath with moderately large palettes ; the anterior claws are rather elongate and nearly straight, a little unequal, the front one being rather longer than the other, and dilated beneath : the terminal joint of the middle tarsus and its claws are slender. The female resembles the male in sculpture. The species is allied to Dytiscus arcticus (No. 736), although it is so different in the colour : its sculpture although very remarkable is similar to that of D. arcticus except in being deeper. North America, (Hudson's Bay, Canada, Sitkha). 799. 711. Agabus subfuscatus, n. sp. — Ovalis, sat nitidus, niger, prothorace subaenes- cente, elytris fuscescentibus, basi lateribusque vage testaceis, antennis pedibusque rufo-testaceis ; elytris nullo modo reticulatis, parce subtilissime punctulatis. Long. 7? lat. 4 m.m. The male has the front and middle tarsi with the basal joints slightly thickened and furnished beneath with short hairs which bear below distinct palettes ; the claws of the front feet are rather elongate and nearly simple. The female differs only by the simple tarsi. The species resembles excessively Dytiscus congener (No. 706) but the sculpture of the elytra is slightly different, there being no trace of any reticulation, the hind coxse are distinctly larger, and the prosternal process slightly more developed, and the supra-articular border is much wider. It is equally similar to Dytiscus paludosus (No. 680) but has the mesosternal groove more elongate, and the male tarsi bear distinct palettes. It is possible that this species and not No. 708 may be the Colymbetes ambiguus Say. North America, (Massachusetts). 749. On Aquatic Carnivorous Coleoptera or Dytiscidce. 515 712. Agabus {Gaurodytes) clypealis, Thorns., Sk. Col. IX, p. 107. — Ovalis, nitidu.s, niger, prothorace subi^nescente, lateribus, capite ex pai'te majore elytrisque rufes- ceutibus, his dorso late infuscatis, baud reticulatis, subtilissime punctulatis. Long. ? lat. ? The male has the basal joints of the front and middle tarsi a little incrassate, and furnished beneath with short haii's which bear distinct palettes, the claws of the front feet are but little elongate, and are simple. The female I have not seen. The species is very similar to Agabus subfuscatus, but is shorter, and the male front claws are less elongate, and the prosternal process is broader and shorter ; it differs from Dytiscus congener (No. 706), by its prosternal process, and by the more arched anterior border of the hind coxse which makes the side wino^s of the meta- sternum shorter : it is also extremely similar to Dytiscus paludosus (No. 680), but has the side wing's of the metasternum shorter, and the metasternal oToove longer. Northern Europe, (Sweden and Finland). 767. 713. Dytiscus nebulosus, Forst., Ac/cdjus ncbulosus, 3£C, — Ovalis, hand con vexus, nitidus, subtus niger, supra testaceus, elytris capiteque nigro-variegatis, prothorace in medio stepius nigro-bimaculato, antennis pedibusque cum femoribus testaceis. Long. 8h, lat. 4^ m.m. The markings on the wing cases consist of numerous irregular black spots ; the under surface has the margins and sides of the ventral segments as also the articular portions of the hind coxa3 more or less yellow. The male has the three basal joints of the fi-ont and middle tarsi distinctly inci'assate, and furnished beneath with long hairs which bear palettes at their extremity, the claws of the front feet are rather long, and the anterior one is thickened or obtusely dentate at the extreme base. In both sexes the surface of the elytra seems to be very smooth, but when a careful examination is made it is seen that the females have the basal portion excessively minutely and finely reticulate or coriaceous. Europe, Sardinia, Algeria, Syria, Canary Islands. (Sweden, Britain, Germany, France, Spain). 750. 714. Dytiscus conspersus. Marsh., Agabus conspersus, M.C. — Ovalis, nitidus, (femina interdum subopaca) subtus nigricans, supra flavicans, elytris plus miuusve fusco-nebulosis, capite nigricante vertice testaceo-bimaculato, clypeo testaceo, antennis pedibusque rufis, his femoribus plus minusve late infuscatis. Long. 8, lat. 4} m.m. This species is variable in the colour of the upper surface which is sometimes, with the exception of the variegated head entirely pallid, the elytra are generally however suffused with vague dark marks, and sometimes the middle of the thorax is also infuscate. The male has the front and middle tarsi with the thi-ee basal joints a good deal incrassate, and furnished beneath with long hairs which bear TEANS. EOT. DUB. SOC, N.S., VOL. II. 3 3; 516 On Aquatic Carnivorous Coleoptera or Dytiscidce. palettes ; the claws of the anterior feet are not elongate, and the front one has the basal half or more a good deal thicker beneath than the apical portion. The females vary much in sculpture, sometimes they are as smooth and shining above as the males, while in the other extreme the surface is quite opaque from a very dense and fine reticulation ; forms intermediate between these extremes are to be foimd, and it is worth notice that these variations of the female are probably to a great extent locaUsed. In A. godmanni. Crotch, from the Azores, the sculpture of the surface in the female has become excessively deep so that the surface is very opaque and rugose ; and the male has the front and middle tarsi with the basal joints more incrassate, but I cannot consider the form as a distinct species, for in the two males I have seen the claws of the front tarsi are considerably different, in one they are formed as usual in the species, while in the other they are more elongate and have a small tooth near the base ; of the female I have seen but one individual so do not know whether it varies : it appears to me then that this wiU prove to be merely a variety, because there is nothing to distinguish it from Continental specimens except certain sexual disparities and these it seems are variable. Europe, Corsica, Algeria, Trans-Caucasus, Meso])otamia, Azores; (Denmark, Scotland, England, France, Germany, Spain). 751. 715. Agabus austinii, (Crotch), n. sp. — Ovalis, sat convexus, nitidus, subtus capite prosternoque rufis, hoc medio pectore abdomineque nigricantibus, hoc plus minus rufo-variegato, supra fuscus, capite anterius et prothoracis elytro- rumque lateribus rufis, antennis pedibusque rufo-testaceis ; supra undique evidenter reticulatus, reticulis magnis. Long. 9i, lat. 5 m.m. The male has the front and middle tarsi distinctly incrassate, and furnished beneath, on a rather narrow space, with moderately long glandular hairs ; tlie claws of the front feet are elongate and nearly straight, and have a swelling at the extreme base, there is no difierence in the sculpture of the sexes. North America, (British Columbia). 792. 716.1 )y tiscus striolatus, Gyll. , Agabus striolatus, M. C. — Oblongo-ovalis, elongatus, angustulus, minus nitidus, niger, antennis pedibusque rufis; supra undique evidentius reticulatus, retis in elytris elongatis ; prothorace angulis posterioribus obtusiusculis. Long. 7, lat. 4 m.m. The male has the three basal joints of the front and middle tarsi a little incrassate, and furnished beneath with moderately long glandular hairs, the claws of the front feet are rather long, and are simple. In other respects the sexes are quite similar. Northern Eui-ope ; a i-are species, (Sweden, Finland, England, the Rhine province ; basin of the Seine). 760. On Aquatic Carnivorous Coleoptera or DytiscidcB. SIT' 71 7. Agabus (Gaurodytes) strigulosus, Crotch, Tr. Am. Ent. Soc. IV, p. 422. — Oblongo-ovalis, angustuliis, niger, supra fuscescens, prothorace elytrorumque lateribus vage testaceis, antennis pedibusque rufis ; supra ubique evidenter reticulatus. Long. 6, lat. 3 m.m. In this species, the reticulation of the upper surface though fine is quite distinct, and forms large meshes, which are as conspicuous on the head and tlaorax as on the elytra. The male has the three basal joints of the front and middle tarsi distinctly incrassate, and furnished beneath with short hairs which bear distinct palettes. The female I have not seen. The prosternal process in this species is moderately compressed, and is much punctulate : by the form and sculpture a relationship with Dytiscus striolatus is suggested, but the male tarsi are differently clothed, and the supra-articular border is quite ordinary. North America, (California). 748. Group 11. Outline of thorax and elytra discontinuous, male front tarsi slender, but with long claws j prosternal process rather small, nearly Hat, very finely margined, feebly punctate ; metasternal groove imperfect ; swimming legs elongate, slender, and feeble ; hind coxse rather small, but wings of metasternum not large. Two Old World (Siberian) species. 718. Agabus sahlbergi, n. sp. — (? Oblongo-ovalis, niger, nitidus, antennis palpis pedibusque rufis ; prothorace lateribus leviter rotundatis, basi utrinque subrotundato, angulis posterioribus obtusiusculis, margine laterali crasso ; elytris nitidis subtihus reticulatis, versus apicem nitidis baud rugosis. Long. 7i, lat. 4i m.m. This species is shorter than Agabus armeniacus (No. 671), and has the base of the thorax a little more curved and the hind angles more obtuse, and the reticulation of the elytra is not quite so distinct. The difference in the sculpture of the elytra, and the shape of the hind angles of the thorax distinguish it from Dytiscus guttatus (No. 670), to which it is closely allied. I have seen but a single individual, which is a male, and has the three basal joints of the front and middle tarsi a little incrassate and furnished beneath with short hairs ; the claws of the front feet are elongate and slender, and a little sinuate, especially the anterior one. 3X2 518 On Aquatic Carnivorous Coleoptera or Dytiscidce. According to Professor Sahlberg this is the species Matinerheim intended to call A. adjiressus, but is not the one described by Aube under that name, (vide No. 719). Dauria. 726. 719. Agabus adpressus, Aube, M.C. — Oblongo-ovalis, niger, nitidus, supra ainescens, clypeo rufescente, antennis pedibusque rufis ; prothorace lateribus sat rotundatis, angulis posterioribus obtusis. Long. 7, lat. 3f m.m. There is a difterence in the sculj^ture of the sexes, the female having the elytra extremely finely reticulate, while in the male the reticulation is so obsolete as to easily escape detection : the male has the basal joints of the front and middle tarsi a little incrassate, and furnished beneath with glandular hairs, and the claws of the front feet are elongate and slightly sinuate beneath. The prosternal process in this species is not broad, and is but little compressed laterally, and is feebly punctulate at the sides, the metasternal cavity is rather short and narrow. The species is closely allied to Agabus sahlbergi, but is smaller, and the prosternal process is rather shorter flatter and more punctate, and the sides of the thorax are more contracted at the hind angles. Arctic Siberia, (Dudinka, J. Sahlberg). 738. Group 12. Prosternal process small, much compressed ; middle legs very approximate so that the metasternal groove between these is o^udimentary and obscure. Sides oj thorax rounded. Coxal lines rather deep and a good deal divergent in front. Four species from both Old and New Worlds. 720. Dytiscus wasastjernse, Sahl., Agabus Wasastjernce, M.C. — Oblongo-ovalis, niger, supra subsenescens, sat nitidus, antennis pedibusque rufis; prothorace lateribus rotundatis, angulis posterioribus rotundato-obtusis, margine laterali baud crasso; elytris dense evidenter reticulatis et punctulati-^. Long. 7, lat. 4 m.m. The sexes are vei7 similar ; in the male the three basal joints of the front and middle tarsi are scarcely incrassate but are furnished beneath with glandular haii'S. The apical joints of the antennae in this species are rather more elongate and slender than in the allies. Northern Europe; (Sweden, and Finland). 739. On Aquatic Carnivorous Coleoptera or Dytiscidce. 519 721. Agabus (Gaurodytes) miinmi, Sahl., Not. fenn. XIV, p. 182. — Oblongo- ovalis, niger, supra senescens, antennis pedibusque rufis, vel nitidus et in elytris subtiliter reticulatus punctulatiisque (S), vel sericeo-opacus et subtilissime reti- culatus, (p) ; prothoi'ace lato, anterius conspicue angustato, lateribus curvatis, angulis posterioribus rotundato-obtusis, margine lateral! baud crasso. Long. 7i, lat. 4 m.m. The male has the three basal joints of the front and middle tarsi a little incras- sate and furnished beneath with rather dense and short glandular hairs, the claws of the front feet are elongate, but are scarcely visibly sinuate beneath; the difference in the sculpture of the upper surface in the sexes is very conspicuous. Northern Euroi)e, (Finland to 66^ 10', according to Sahlberg). 740. 722. Agabus sibericus, n. sp. — Oblongo-ovalis, niger, supra aenescens, sat nitidus, antennis pedibusque rufis ; prothorace lato, anterius conspicue angustato, lateribus curvatis, angulis posterioribus rotundatis, obtusis, margine laterali baud crasso ; elytris crebre conspicue reticulatis et punctulatis. Long. Si, lat. 4|- m.m. Li the male the three basal joints of the front and middle tarsi are a good deal in- crassate and furnished beneath with glandular hairs, the claws of the front feet are elongate, but scarcely visibly sinuate beneath ; the species is very closely allied to Dytiscus wasastjernae but is larger, and the male has the front tarsi much more differentiated from those of the female. Eastern Siberia. 741. 723. Agabus [Gaurodytes) walsinghami. Crotch, Tr. Am. Ent. Soc. IV, p. 419. — Oblongo-ovalis, niger supra aenescens, nitidus, antennis rufis, pedibus piceo-rufis, illis apice summo nigricante ; prothorace anterius angustato, lateribus leviter curvatis, angulis posterioribus obtusis, subrotundatis, margine laterali lato ; elytris crebrius subtiliter reticulatis, et inconspicue punctulatis, pone medium guttula tenui pallida. Long. 92, lat. 5 m.m. The male has the three basal joints of the front and middle tarsi distinctly incrassate and furnished beneath with long glandular hairs, the claws of the front feet are much elongate and sinuate beneath. There is also a slight but distinct difference in the sculpture of the sexes, the female having a slight silky opacity on the elytra : the front of the head and the sides of the thorax towards the front are rufescent. North America, (Oregon). 742. 520 On Aquatic Carnivorous Coleoj^tera or Dytiscidce. Group 13. Prosternal process acutely raised or carinate along the middle, but its sides little depressed, so that it is not compressed, tlie sides evenly and distinctly margined ; metasternal groove well developed ; swimming legs elongate, rather slender ; wings of metasternum large or moderate ; male front tarsi little incrassate, their claws elongate. Two species, found in both the Old and New Worlds. 724. Dytiseus confinis, Gyll., Agabiis confinis, M.C. — Oblongo-ovalis, nitidus, sub- Isevigatus, niger, elytris fusco-nigris, externe vage rufescentibus, antennis pedibusque rufis, femoribus plus minusve piceis ; elytris vix perspicue punctulatis. Long. 9, lat. 4i m.m. In the male the three basal ioints of the front tarsi are but little thickened, and bear beneath small palettes which scarcely appear to be placed on hairs, the claws of the front feet are elongate, little curved, and scarcely sinuate beneath. In each sex the elytra appear smooth and shining, but when cai'efully examined excessively fine and obsolete distant punctui'es are found to exist, and moreover the female has excessively dense and fine regular reticulation. Northern Europe, and North America. (Sweden ; Finland to 68° North, Sahlberg ; Lake Superior ; Kansas). 752. 725. Agabus infuscatus, Aube, Spec. p. 330. — Oblongo-ovalis, niger, prothoracis lateribus vage rufescentibus, elj^tris fusco-nebulosis ad latera pallidioribus, antennis pedibusque rufis, femoribus infuscatis ; elytris densius subtilissimeque reticulatis, minus nitidis, punctis subseriatis et apicalibus subobsoletis. Long. 8, lat. 4l m.m. This species is readily distinguished by the peculiar uneven or rugose surface of the intra-linear portions of the hind coxfe. The male has the three basal joints of the front and middle tarsi but little incrassate, and furnished beneath with small palettes which do not appear to be placed on hairs ; the claws of the front feet are elongate and almost straight and simple : the apical portions of the sixth to tenth joints of the antennaa are a little swollen internally at the apex. The sculpture appears to be the same in each sex. I have great difficulty in believing this to be Aube's A. infuscatus, though it is so identified by Leconte and others. United States of North America, (Lake Superior). 753, On Aquatic Carnivorous Coleoptera or Dytiscidce. 521 Group 14. Hind coxEe large, ivith acutely arched upper border ; wings of the metasternum very slender ; prosternal process rather small ; swimming legs ratlaer slender ; male front tarsi but little incrassate. Two European species. 726. Dytiscus femoralis, Payk., Agabus femoralis, M.C. — Ovalis, minus convexus, niger, nitidus, supra aenescens, capite anterius, prothoracis elytrorumque lateribus rufescentibus, antennis pedibusque rufis ; elytris subobsolete reticulatis, sed evidenter punctulatis ; protborace margine laterali lato. Long. 6, lat. oh m.m. In the male the basal joints of the front and middle tarsi are slightly thickened, and furnished beneath with moderately long glandular hairs, the claws of the front feet are elongate, and nearly straight and simple ; in this sex the front femora are fringed beneath with dense long cilise : there is no sexual disparity of sculpture. Northern Europe ; (Sweden ; Finland to 68° 30' according to Sahlberg ; Britain, Fi-ance, Belgium, Germany). 758. 727. Dytiscus abbreviatus. Fab., Agahus abhreviatus, M.C. — Ovalis, sat convexus, sat nitidus, subtus rufescens, plus minusve picescens, supra aenescens, capite prothoracisque lateribus ferrugineis, elytris fascia transversa subbasali undulata, macula flammulata pone medium versus latera, alteraque apicali parvula, rotundata testaceis, antennis pedibusque rufis ; elytris densis?ime vix perspicue reticulatis subtilissimeque punctulatis. Long. 7*-, lat. 4 m.m. The male has the three basal joints of the front and middle tarsi a little incrassate, and furnished beneath with rather long hairs, which bear small palettes at their apex, the claws scarcely differ from those of the female. The species is easily distinguished amongst its allies by the pale transverse fascia near the base of the elytra ; the external portion of the elytra towards the base is also more or less pale. Central Europe ; (Sweden, England, Germany, Belgium, France). 770. Group 15. Sides of thorax very finely margined, not at all curved ; prosternal process very flat, not visibly margined ; metasternal groove rather elongate ; wings of metaster- num large ; front border of hind coxa3 little arched ; swimming legs feeble, and elongate ; male front tarsi with the basal joints but little incrassate, the fifth joint angularly dilated in the middle beneath; claws elongate. A single North European species. 522 On Aquatic Carnivorous Coleoptera or Dytiscidce. 728. Dytiscus elongatus, GjW., Acjahus elongotiis,M. C. — Oblongo-ovali.s,angustulus, niger, supra fusco-subseneus, antennis pedibusque testaceis, femoribus plus minusve infuscatis ; elytris omnino densissime subtilissimeque reticulatis, sat nitidis ; prothorace lateribus baud cui'vatis, margine laterali subtili. Long. 7, lat. 3j m.m. In the male the front tarsi are peculiar in form, the basal joint is a little thickened at its extremity, but the hairs on it and the following two joints are very little indeed, the fifth joint is elongate, and is underneath incrassate about the middle, the claws are elongate, and at the base abruptly bent, especially the hinder one, they are without tooth, but are a little sinuate. The intermediate tarsi have the basal joint a good deal thickened, it and the two following ones bearing a few extremely short and indistinct glandular hairs. There is no difference in the sculpture of the sexes. The antennae of this species have a peculiarity, (pointed out by C. J. Thomson) which is not however very conspicuous ; they have the 6th to 9th joints a little thickened at the extremity at the lower angle ; this is more conspicuous in the male than it is in the female, and the prominent spot in the former sex seems to be a fovea filled with a glandular pubescence. Northeni Europe ; (Sweden, and Finland to 64°, according to Sahlberg). 765. Group 16. Prosternal process compressed on its apical half or through its whole length, finely but quite distinctly margined ; wings of metasternum large, or moderately large ; swimming legs moderately short ; reticulation of upper surface frequently very conspicuous ; male front tarsi much incrassate and dilated, their claws various, either short and dentate beneath, or elongate, or very elongate. Seven species, six of them North American, and one North European. 729. Agabus reticulatus, Aube, Spec. p. 355. — Ovalis, sat convexus, niger, elytris fuscis vel fusco-nigris, limbo externo rufescente, prothorace ad latera anguste minus distincte rufescente, antennis pedibusque rufis, posterioribus piceis ; supra undique evidenter reticulatus, vel sat nitidus (cj) et reticulis .sat magais, vel sub- opacus (?) et reticulis baud magnis. Long. 8, lat. 41 m.m. The male has the basal joints of the Iront and middle tarsi a great deal incrassate, and broadly furnished beneath witli hairs ol' which the terminal half bear three On Aquatic Carnivorous Coleoptera or Dytiscidce. 523 series of small palettes, the claws of the front feet are elougate and nearly straight ; the female has the upper surface less shining than the male, and the meshes of the reticulation smaller. North America. (Lake Superior, Pennsylvania). 793. 730. Agabus obsoletus, Lec.(?), M.C. — Ovalis, minus convexus, niger, elytris fu&co-nigris, ad humeros plusminusve indistincte rufescentibus, prothoracis lateribus vix ferrugineis, antennis pedibusque rufis, his plus minusve picescentibus. Long. 8, lat. 42 m.m. Mas, nitidus, fere laevigatus, densissime obsoletissimeque reticulatus. Fern., elytris subopacis, densius sat profundeque reticulatis, ad apicem leevigatis, reticulis fere parvis. The male has the three basal joints of the front and middle tarsi much incrassate, and furnished beneath with rather large palettes, about thirty in number on each foot, the basal palettes seem seated directly on the tarsus while the outer ones are borne on hairs ; the claws on the front feet are elongate and slender, and sinuate beneath. The female of this species much resembles that of Agabus reticulatus, but has the meshes of the reticulation on the elytra smaller, and the apex quite without scratches. Western North America. 796. 731. Agabus {(iaurodytes) lecontei. Crotch, Tr. Am. Ent. Soc. IV, p. 417. — Ovalis, minus convexus, niger, capite thoraceque seneis, subtiliter (in femina magis conspicue) reticulatis, elytris fusco-rufis, antennis pedibusque rufis, his plus minusve picescentibus. Long. 7f, lat. 4i m.m. Mas, elytris nitidis, fere omnino Isevigatis. Fern., elytris subopacis, dense profundeque reticulatis, reticulis circa scutellum angustis et elongatis, parte apicali fere omnino laevigata. The male has the three basal joints of the front and middle tarsi greatly incrassate, and furnished beneath with rather large palettes ; the claws of the front feet are short, and the anterior one is furnished near the apex with a long slender lobe. The species differs from A. obsoletus by the outline of the thorax and elytra being more continuous, as well as by other characters which will be observed from the above diagnosis. Some individuals have the elytra testaceous, with infuscate nebulosities, and probably will prove a distinct species, but as I have seen only males, and these are very similar in their tarsi &c. to the darker form, I do not think it can be properly considered distinct at present. Western North America. 797. TBAHS. BOT, DUB. SOC, H.S , VOL. II. S T 524 On Aquatic Carnivorous Coleoptera or Dijtiscidce. 732. Agabus griseipennis, Lee, M.C. — Ovalis fere angustulus, minus convexus, niger, capita thoraceque seneis, hoc margine laterali ferrugineo, subtiliter (in femina magis conspicue) reticulatis, elytris testaceis, iufuscatis (basi margineque externo exceptis) ; antennis pedibusque testaceis, femoribus ex parte nigris. Long. 8, lat. 44 m.m. Alas, elyti'is nitidis, fere omnino Itevigatis. Fetn., elytris subopacis, dense profundiusque reticulatis ; parte apicali omnino laevigata. In the male the three basal joints of the front tarsi are greatly incrassate and but little compressed, and are furnished lieneath with large palettes, the fourth joint is unusually short, the claws are quite short, and the anterior one is thick, with a slender termination : the intermediate tarsi have the four basal joints much incrassate, and the three basal furnished beneath with large palettes, the claws of the elongate fifth joint are unequal, the hinder or inner one being rather the shorter, and incrassate with a slender, much curved, termination. Though this species much resembles the pale form of A. lecontei, it is distin- guished by its narrower, more elongate form, and the slight but quite undoubted differences in the structure of the male feet ; the reticulation of the upper surface in the female is deeper than in A. lecontei. Western Xorth America, (Nevada). 798. 733. Agabus {Gaurodytes) zetterstedti, Thoms., M.C. — Oblongo-ovalis, minus convexus, subnitidus, niger, capite prothoraceque Eenescentibus, elytris fuscis, lateribus dilutioribus, antennis pedibusque testaceis ; supra undique densius reticulatus. Long. 9, lat. 5 m.m. The ma^e has the front and middle tarsi mvich incrassate, and furnished beneath with large palettes ; the claws of the fi-ont feet are rather elongate and stout, and but little curved, and slightly sinuate beneath ; the sculpture of the upper surface is not so deep as in the female. The species has much superficial resemblance to Dytiscus sturmi (No. 737), but is more elongate, and has the upper surface more densely reticulate, and the prostemal process of a different form. Northern Europe, and Sibeiia ; (Sweden ; Finland, to 69° North, Sahlberg). 800. 734. Agabus obliteratus, Lee, M.C. — Ovalis, minus convexus, baud latus, fere leevigatus, pernitidus, niger, antennis pedibusque rufis, femoribus picescentibus ; prothorace margine laterali anguste rufo, elytris fusco-testaceis, basi margineque externo dilutioribus. Long. 8, lat. 4i m.m. The male has the three basal joints of the front and middle tarsi greatly incrassate, and furnished beneath with rather large palettes ; the claws of the front feet are On Aquatic Carnivorous Coleoptera or DytiscidcB. 525 elongate and slender, and sinuate beneath : the female agrees with the male in the smooth shining upper surface. I have seen but two individuals of the species, which appears to be extremely closely allied to Agabus obsoletus (No. 730), but has the thorax rather smaller, and rather less continuous in outline with the elytra, the colour paler, and the elytra in the female smooth. North America, (Kansas). 801. 735. Colymbetes erythropterus. Say, Agabus erythro)>tervs, M.C. — Minus regulariter ovalis, minus convexus, haud nitidus, niger, elytris fuscis, margine externo late rufescente, antennis et tibiis anterioribus rufis, pedibus posterioribus piceis ; supra undique crebrius reticulatus ; prothorace lateribus conspicue rotundatis. Long. 92, lat. 5i m.m. The structure of the male feet is very remarkable in this species, the anterior tarsi are much iacrassate and compressed, both the fourth and fifth joints being stout, the first joint underneath has its larger portion bare and its apical one densely clothed with glandular hairs, while the hairs on the two following joints bear rather large palettes, the front claws are largely developed and peculiar, the anterior one being greatly thickened beneath, and so with a rounded outline, while its upper edge is nearly straight, the slender hinder one when looked at from behind appears grooved ; both bear a small angular tooth at their extreme base : the three basal joints of the middle tarsi are clothed beneath in a similar manner to the front ones, and the fourth joint on middle and front feet seems to be hollow beneath, but to have the cavity clothed with dense short cilise on each side, the fifth joint of the middle foot is very elongate and its claws large. There is a remarkable sexual difference in the sculpture of the elytra ; in the male their surface is covered with well marked reticulations which form (very irregularly) quadrate meshes ; while in the female the basal portion of the elytra is densely covered with longitudinal scratches, which form very elongate slender meshes, while the sculpture at the apex is similar to that of the male. The male seems to be rather larger than the female. North America, (Lake Superior, Pennsylvania). 804. Group 17. Prosternal process flat, very finely or indistinctly margined ; male front tarsi much incrassate, and furnished heneuth with remarkably large palettes ; wings of meta- sternum only moderately large ; swimming legs moderately long and stout ; surface conspicuously reticulate. Two European species. 3 T 2 526 On Aquatic Carnivorous Coleopiera or Dytiscida;. 736. Dytiscus arcticus, Payk., Agahus arclirus, M.C. — Ovalis, angustulus, supra minus convexus, minus nitidus, subtus nigricans, capite prosternoque ox parte testaceis, supra fusculus, capite anterius, prothorace lateribus vittaque transversa in medio, elytris lateribus, aiitennis pedibusque testaceis ; supra undique conspicue, crebrius, irreguiariter reticulatus ; prothorace margine laterali persubtili. Long. 7, lat. 3| m.m. The male has the front and middle tarsi much incrassate, and furnished beneath with large quite circular palettes, which appear to be seated directly on the tarsus and are about ten or twelve in number : the front claws are unequal, the posterior one being rather elongate, and slender and sinuate beneath, while the anterior one is rather shorter, and has the basal half thickened so as to form an angular pro- jection beneath. The scratches on the upper surface are very deep in the female, and in this sex there is generally, but not always, a peculiar sinuation of the sides of the thorax just behind the front angles. The colour varies somewhat. Northern Europe; Arctic Siberia; (North America, teste Crotch). Sweden; Finland to G9^ north, Sahlberg ; Scotland ; Alsatia, (coll. Castlenau). 794. 737. Dytiscus sturmi, Gyll., Agahus ■sturmi, M.C. — Ovalis, sat convexus, minus nitidus, nigricans, supra fuscus, capite thoraceque subsenescentibus, hujus olytro- rumque lateribus testaceis, antennis pedibusque testaceis, femoribus medio nigricantibus ; supra undique subtiliter erebre reticulatus ; prothorace margine laterali subtili. Long. 8, lat 42 m.m. The male has the front and middle tarsi a great deal incrassate, and furnished beneath with large palettes which are about twelve in number ; the front claws are rather elongate and of about one length and the anterior one is nearly straight "beneath ; the apical joint of the middle tarsus is very elongate : there is no differ- ence of sculpture in the sexes. The colour is subject to some variation. Europe ; (Sweden ; Finland to 63° North, Sahlberg ; Britain, France, Belgium, Germany). 795. Group 18. Swimr)iing legs highly developed, short and incrassate ; prosternal process rather broad, but a good deal compressed; wings of metasternum moderately large ; male front tarsi much incrassate, furnished beneath with rather long hairs, bearing rather well developed palettes, claws rather short. One Japanese species. On Aquatic Carnivorous Coleoptera or DytiscidcB. 527 738. Agabus conspicuus, Sharp, Tr. Ent. Soc. Lond., 1873, p. 48. — Regulariter ovalis, convexus, minus nitidus, niger, elytris fuscis ad latera minus discrete rufes- centibus, antennis pedibusque anterioribus testaceis, his femoribus ex parte majore nigricantibus, pedibus postei-ioribus nigris ; supra undique subtiliter sed nuUo modo obsolete reticulatus, reticuHs subtransversis haud parvis. Long. 11, lat. 6i m.m. The male has the three basal joints of the front and middle tarsi distinctly incrassate but much compressed, and furnished beneath with rather long hairs bearing large palettes, the fourth joint is rather elongate ; the anterior claws are rather short, and the front one is thickened beneath, and is emarginate at the base, while the hinder one is thickened at the base ; the claws of the intermediate feet are leather long and stout, and simple : there is no sexual difference in sculpture. This large species is very regular in its outline, the thorax is laj'ge, and is sinuate at the base near the hind angles, so that these are nearly acute, the hind legs are short and stout, the sculpture of the elytra is more distinct than in Dytiscus sturmi, and the meshes of the reticulation are larger and more transverse in their direction than in that species The colour varies slightly ; when the elytra are expanded it is seen that they are of an obscure yellowish colour, clouded with dense fuscous blotches, which are nearly wanting on the outer part. Japan. 803. Group 19. Coxal lines in their anterior part hut little directed outwards. Prosternal process rather broad, but always compressed ; wings of metasternum large or moderate ; male front tarsi and claws variable. Nine species from both Old and New Worlds. 739. Dytiscus chalconotus, Panz., Agabus chalconotus, M.C. — Ovalis, minus convexus, nitidus, niger, supra a;nescens, prothoracis elytrorumque lateribus plus minusve rufescentibus, antennis pedibusque anterioribus rufis, his femoribus pedi- busque posterioribus picescentibus ; elytris dense subtiliter reticulatis. Long. 8, lat. 4i, m.m. The male has the three basal joints of the front and middle tarsi a little incrassate and furnished beneath with moderately long glandular hairs ; the claws of the front feet are moderately long, simple, and very nearly equal : the apical ventral segment is rugose towards the apex especially on each side of the middle. The species varies somewhat in size and colour. Europe, Sardinia, Algeria. (Sweden, Finland, Britain, Germany, France, Spain). 771. 528 On Aquatic Carnivorous Coleoptcra or Dytiscidce. 740. Agabus altaicu^, Gebl., M.C. — Ovalis, vix convexus, nitidus, iiigcr, supra jEnescens, prothoracis elytrorumque lateribus plus minusve rufescentibus, autennis pedibusque rufis, pobturioiibus picescentibus ; elytris dense subtiliter reticulatis subtiliterque subpunctatis. Long. 7, lat. 4 m.m. The male has the three basal joints of the front and middle tarsi slightly incras- sate, and furnished beneath with moderately long glandular hairs ; the claws of the front feet are moderately long, and almost simple, there being only a very slight emargination beneath near the base ; the apical ventral segment is rugose at the apex. The species is very closely allied to Dytiscus chalconotus, but is smaller, and has the metasternal groove considerably smaller ; and the sculpture of the elytra shows more^distinctly than in D. chalconotus, that the reticulation has excessively fine punctures placed on it. Siberia. 772. 741. Dytiscus vittiger, Gyll., Agahus vittiger, M.C. — -Oblongo-ovalis, convexus, niger, nitidus, supra plus minusve renescens, antennis pedibusque rufis, feraoribus picescentibus ; elytris evidenter reticulatis, punctis subseriatis majoribus ; pone medium vitta parvula laterali maculaque apicali minuta pallidis ; prothorace angulis posterioribus rotundatis. Long. 82, lat. 4^ m.m. The male has only an extremely slight thickening of the basal joints of the front and middle tarsi, and they are furnished beneath with short glandular hairs, and the claws of the front feet are rather elongate and nearly simple ; there is no difference in the sculpture of the upper surface in the sexes ; but the apical ventral segment is in the male very deeply strigose, while in the female it is pinched up in the middle, so as to form a short very elevated plica at the apex. Northern Europe, (Sweden; Finland to 68° 30', Sahlberg). 759. 742. Agabus negleotus, Er., M.C. — Ovalis, vix convexus, subnitidus, niger, supra senescens, prothoracis elytrorumque lateribus plus minusve rufescentibus, antennis pedibus(jue rufis, posterioribus piceis ; elytris densius' subtiliusque reticulatis, et (prsesertim versus apicem) subtilius punctulatis. Long. 8, lat. 4f m.m. The male has the three basal joints of the front and middle tarsi a little incrassate, and furnished beneath with moderately long glandular hairs; the claws of the front feet are rather long, and their lower edge is a little emarginate near the base so as to render the outline sinuous ; the ajiical ventral segment is very deeply and coarsely rugose. Though very closely allied to Dytiscus chalconotus (No. 739), this is an undoubtedly distinct species; the sculpture of the upper surface is finer and denser, and the fine punctures placed on the meshes or reticulations of the elytra are more distinguishable. It is still more closely allied to Agabus altaicus. On Aquatic Carnivorous Coleoptera or Dytiscid(B. 529 but is considerably larger, and the rugosity of the apical ventral segment in the male is much greater. The few specimens before me show a little variation in the length of the lirosternal process, and in the size of the metasternal groove. Northern Europe, (Germany ; France ; a very rare species). 774. 743. Agabus nigro-peneus, Er., Kaf. Mark. I, p. 157. — Oblongo-ovalis, sat convexus, minus nitidus, niger, supra nigro-asneus, prothoracis elytrorumque marginibus obscure ferrugineis, antennis rufis, pedibu^ piceis ; elytris dense con- spicueque reticulatis. Long. 10, lat. 5f m.m. The male has the front and middle tarsi a good deal incrassate, and the three basal joints furnished beneath with rather long glandular hairs, some of which are developed into distinct palettes : on the anterior feet the front claw has the basal portion a good deal thickened, while the posterior one is a good deal emarginate beneath near the base : the apical ventral segment bears deep oblique furrows, which scarcely extend to the flattened or depressed middle portion : the claws of the hind tarsi are shorter and stouter in the male than in the female : and in the former sex the three basal joints of the hind tarsi are provided beneath with swimming hairs, while in the males of the allied species such hairs are confined to the first joint. Northern Europe, Siberia, Nortli America ; (Sweden ; Finhind ; France ; Germany ; Hudson's Bay } Canada J California). 776. 744. Agabus subtilis, Er., M.C. — Ovalis, sat convexus, minus nitidus, niger, supra nigro-seneus, antennis rufis, pedibus piceo-rufis; elytris densius subtiliusque reticulatis. Long 95, lat. 5i m.m. The male has the front and middle tarsi a sfood deal inci-assate, and the three basal joints rather thickly furnished beneath with moderately long glandular hairs, some of which are developed into minute palettes ; the anterior claw of the front feet is a good deal thickened in its basal portion, while the posterior one is slightly emarginate near the base : the apical ventral segment is deeply strigose longitudinally on each side of the middle : the hind tarsi in the male also are peculiar in form and greatly approximate to what prevails in the genus Ilybius, the fourth joint being externally a little lobed at its lower posterior angle, while the fifth joint is thicker than in the female, and has its lower edge emarginate, and the claws shorter, thicker, and more unequal than in the female. The species greatly resembles Agabus neglectus, but it is larger, and the males are readily distinguished by the structural peculiarities ; the females are extremely similar, and except for the larger size of A. subtilis it would be very difficult to distinguish them : A. subtilis p has however the minute punctuation on the apical 530 On Aquatic Carnivorous Coleoptera or Di/tiscida'. portion of theelytra more indistinct than it is in A. neglectu?, and the piothorax decidedly a little longer. Northern Europe, and Siberia ; (Sweden, Finland, Denmark, Germany, Kirgisia, coll. Castlenan). 744. 745. Ao-abus politus, Reiche, M.C. — Ovalis, latiusculus, pernitidus, haud convexus, niger, supra suba3nescens, protlioraci-s elytrorumque lateribus obscure ferrugineis, Jintennis pedibusque anterioribus rufis, posterioribus piceis ; elytris crebre fere obsolete reticulatis. Long. 10, lat. 5i m.m. The male has the three basal joints of the front and middle tarsi a little incrassate and furnished beneath with moderately long glandular hairs, the claws of the front feet are slender and simple but rather long. The species is closely allied to Agabus gagates, but is slightly larger, and the reticulation of the upper surface is more effaced, and the lateral margin of the pro thorax is rather broader. When immature this species is entirely pale beneath. Algeria. 777. 746. Ao-abus gagate?, Aube, Spec. p. 306. — Ovalis, latiusculus, nitidus, haud convexus, subtus prosterno me-sosternoque ferrugineis, pectore abdomineque piceis, supra £enescens, prothoracis elytrorumque lateribus plus minusve rufescentibus ; antennis pedibusque rufis ; elytris dense subtiliter reticulatis ; prothorace margine laterali angusto. Long. 9, lat. 5 m.m. The male has the three basal joints of the front and middle tarsi slightly incrassate, and furnished beneath with moderately long glandular hairs ; the claws of the front feet are rather long and nearly simple, but each has underneath a minute thickening at some distance from the base, causing the outline to appear a little sinuate. The species greatly resembles the larger individuals of Dytiscus chalconotus (No. 739), but is readily distinguished by the narrower pronotal margin. North America, (Lake Superior, Pennsylvania). 773. 747. Agabus discors, Lee, M.C. — Oblongo-ovalis, haud nitidus, nee convexus, niger, antennis pedibusque rufis, femoribus picescentibus ; supra profunde striolato- reticulatus : prothorace lateribus rotundatis, angulis posterioribus obtusis ; antennis elongatis. Long. 11, lat. 5f m.m. The male has the front and middle tarsi distinctly incrassate, and amply provided beneath with dense elongate hairs not bearing palettes; the anterior claws are elono-ate, little curved, and distinctly sinuate beneath : two joints of the hind tarsi have swimming hairs beneath. The female I have not seen. This species has the broad prosternal process greatly compressed, and the middle On Aquatic Carnivorous Coleoptera or Dytiscidce. 531 legs very approximate, so that the metasternal groove is excessively narrow and indistinct. North America, (Oregou, Vancouvei-'s Island). 790. Group 20. Coxal harder very wide ; the coxal lines gently, not abruptly, turned outwards at the extremity ; prosternal process punctulate, slightly raised along the middle. Four species from both Old and New Worlds. 748. Agabus melanarius, Aube, Spec. p. .353, Agahus tarsatus, J/. C — Oblongo- ovalis, niger, sat nitidus, supra hand perspicue genescens, antennis rutis, pedibus piceis ; fortiter conspicue reticulatus, prothorace lateribus vix rotuudatis, angulis posterioribus obtuse rectis ; prosterni processu punctulato medio glabro. Long. 9, lat. 5 m.m. The male has the three basal joints of the front and middle tarsi a little thickened, and furnished beneath with very short glandular hairs : the anterior claw of the front foot is slightly thickened, and its lower margin a little sinuate. Northern Europe. (Sweden, Finland, Denmark, Germany, Russia). 730. 749. Agabus tristis, Aube, M.C. — Oblongo-ovalis, superne minus convexus, sat Tiitidus, fusco-niger, prothoracis lateribus, et vitta transversa post marginem anterio- rem, elytrisquehumeris plus minusve discrete rufescenti bus, antennis pedibusque rufis, posterioribus plus minusve infuscatis, corpore subtus plus minusve rufo-variegato ; .supra undique evidenter reticulatus reticulis magnis. Long. lOi, lat. 5j m.m. The male has the three basal joints of the front and middle tarsi much incrassate and amply furnished beneath with short glandular hairs : the claws of the front feet are moderately long, and are scarcely at all more developed than in the female, but the anterior one has a tooth at its extreme base : there is a .slight difference in the sculpture of the sexes, the female having the scratches on the basal portion of the elytra placed in a rather more regular and oblique direction, and the meshes formed by them are more elongate. The species varies a good deal in colour. Eussian America: Arctic Sibei-ia, (Diidinka, Sahlberg). 791. 750. Agabus woUastoni, u. ^). — Mas et femina perdissimiles ; oblongo-ovalis, minus convexus, subtus niger, antennis palpis pedibusque rufis ; supra undique subtiliter sed evidenter reticulatus ; prothorace basi elytrorum latitudine, lateribus obliquis, minus rotundatis, anguUs posterioribus vix obtusis. Long. 11, lat. 6 m.m. TRANS, ROY. DIB. SOC, N.S.. VOL. II. ^ ^ 532 On Aquatic Carnivorous Coleoptera or DytiscidcB. Mas, nitidus, elytris fusco-ceneis, elyti'orum reticulis sat elongatis. Long. 12 m.in. Fern., opaca, elytris fusco-sub-rutis, ad apicein sat nitidis, subtilius reticulatis, reticulis elongatis, tantum ad apiceui latioribus et brevioribus. Long. 11 m.m. The male has the three basal joints of the front and middle tarsi incrassate, and furnished beneath with glandular hairs, the outer portion of which bear about three series of ill-developed palettes; the claws of both feet are rather elongate, equal and simple : the sexual difference in sculpture and appearance is very striking. Though the species is approximated by the various varieties of Dytiscus bipus- tulatus, yet on the whole it seems to me that it must be considered a distinct species, until sufficiently intermediate forms can be brought forward. The simple structure of the male tarsal claws, is a prominent distinctive character ; the female is excessively close in appearance to the p var. (Agabus solieri, Aub^). of A. bipus- tulatus, but it has not the sides of the thorax rounded ; in both sexes the prosternal process is rather broader and flatter than in Dytiscus bipustulatus, approximating to that of Agabus melanarius, Aube. Madeira. 806. 751. Dytiscus bipustulatus, Linn., Agabus bipustulatus, M.C. — Species per varia^ bills ; supra et infra undique strigulosus, niger, supra plus minusve senescens, antennis palpisque rufis, pedibus piceis, anterioribus dilutioribus ; reticulis elytrorum semper in parte basali longitudinalibus, s^epius angustis et elongatis. Long. 10, lat. 5i The male has the three basal joints of the front and middle tarsi much incrassate, and furnished beneath with glandular hairs, the outer portion of which bear about three rows of ill-developed palettes; a considerable portion of the basal joint on the front feet is bare. The anterior claws are unequal, the front one being moderately long, and bearing a small tooth beneath at the extreme base, while the hinder one is elongate and much dilated behind, the swelling extending over the greater part of the length of the claw but leaving the extremity slender, and causing the outline behind to be much sinuate : the claws on the middle feet are also unequal, both are elongate and very little curved, the anterior one being considerably longer than the other. There is generally a sexual difference in the sculpture of the upper surface the female being duller than the male, and having the longitudinal strias finer and denser, and on the humeral portion taking a more oblique outward direction, the sculpture at the extreme apex is the same as in the male. This species which is perhaps the commonest of the European Dj'tiscidpe is extremely variable as regards size, colour, form, sculpture, sexual disparity, and the form of the male tarsi : the broad supra articular border readil\- distinguishes it from the other European allies, except A. melanarius, Aube, and that species always On Aquatic Carnivorous Coleoptera or Dytisciche. 533 has the meshes of the reticulatioa on the el3'tra comparatively broader and shorter, and the prosternal process less compressed at the sides. Europe, throughout, from Iceland and 69° North according to Sahlberg, to Spain and Portugal ; Corsica ; Sardinia, Sicily, Algeria, Syria, Persia. 805. , . The variation found in this species is very complex and interesting. The ordinary form may be considered to be that in which the female has the surface duller than the male and the longitudinal scratches finer, denser and more oblique, the general form in both sexes being rather regularly oval, the female however being generally just a little narrower and more oblong than the male : on examination under the compound microscope with a half-inch object glass, it appears that the dullness of the surface in the female is caused by minute scale-like reticulations, which are not so deep in the male as in the other sex : this form is that universally found in temperate Europe, and I have it in my collection from as far east as Persia : the size about 9 — 11 m.m. long, 5 — 52 m.m. broad: this maybe called the ordinary or typical form. In some of the warmer parts of Europe, there are found large specimens in which ihe sculpture in the female is quite similar to that of the male, which, as in the ordinary form just mentioned, consists of very elongate, narrow meshes on the basal portion of the elytra : this may be called the South European variety. In the highland districts of Britain, and in the Alps and Iceland, the specimens become smaller, and of a narrower, more oblong and depressed form with the base of the thorax narrower than that of the elytra, and tlie surface in the female excessively dull, so that the disparity in the appearance of the two sexes is very great : but this form (for females of which Aube proposed the name " Agabus solieri") is connected with the common temperate European form by every shade of intermediate variation: this maj' be called the dimorphic Alpine form. In some localities in the Alps and Pyrenees there are found (I believe always at a great elevation) specimens of elongate, narrow and depressed form, with very shining surface, the sculpture in the female being similar to that of the male, and the meshes of the reticulation of the elytra are generally rather broader and shorter than in the ordinary temperate European form. This form has been found by Kiesenwetter in the Alps of Carniola; and has also occurred at Lago Pinter, and in the Hautes Pyrenees; it may be called the monomorphic .A.lpine form. We have thus the peculiar anomaly that in some Alpine districts the sexual divergence in sculpture of the female from the male is much increased, while in other Alpine districts there is on the contrary convergence of the sculpture of the female to the male, or in fact absolute similarity. I have no evidence that these two Alpine forms of the female are ever found together, indeed all the evidence I have indicates the contrary ; thus though I have found great numbers of the dimorphic Alpine form in the mountains about Braemar, I have never found a single female with sculpture at all like that 3 Z 2 534 On Aquatic Carnivorous Coleo2')tera or Dijtiscidce. of the male, while the females before me from Lago Pinter, .seven in number are all similar to the males. There thus appear to be two Alpine races, the males of the two being similar while the females are very different. The species however not only varies in sculpture both absolutely (that is in both sexes considered together) and sexually, but it .shows quite as great and even more interesting modifications, in what may be called quite structural characters; thus the shape becomes in the Alpine forms very different from what obtains in the plains, and in correspondence with this modification of shape is a change in the legs, which are very much more elongate and slender, (that is less highly developed for swimming) than they are in the individuals of the plain ; this diminution in the power of the legs reaches its extreme in the most divergent females of both the Aljiine forms. The male tarsi are subject also to much variation, the amount of their incrassation and the sexual structure of the front claws being each inconstant ; the greatest development of the male feet and claws is found in the large individuals of the plains, the smalle.st in the Alpine forms ; in these latter the amount of dilatation of the tarsus is greatly diminished, and the posterior of the claws on the front feet becomes more slender, the dilatation of its hinder edge lieing in extreme cases very greatly diminished : the front claws moreover are variable independently of Alpine or boreal localization, for I have a male (from Cor.sica ?) in which the anterior claw retains pretty nearly the normal shape, but is not longer than the front one. It seems very difficult to comprehend these vai'iations. Especially peculiar seems the fact that the males of Alpine and boreal districts depart from the dwellers of the plains in one direction only, and yet their females depart in two opjiosite directions ; equally difficult of explanation is the fact that though disj^arity in sculpture of the sexes is the rule, yet this disparity disappears in the two forms which in other respects are most widely different from one another, viz., the large and powerful South European variety, and the feeble, nionomorphic Alpine variety", we seem however at any rate justified in inferring that the peculiar sculpture of the females bears no correlation to the development of the male tarsi. Group 21. Anterior portion of prosternum united uuth prosteriial process so as to form a sensible angle ; prosternal process compressed : wings of metasternum rather short ; coxal lines not greatly turned outwards at the extremity ; coxal border small ; male anterior tarsi much developed ; hind legs slender. Two Palsearctic species. On Aquatic Carnivorous Coleoptera or DytiscidcB. 535 752. Dytiscus fuscipennis, V-Ayk., Agahus fuscipennis, M.C. — Ovalis, posterius jingustatus, convexus, ferrugineus, subtus plus minusve infuscatus, sat nitidus, fere lievigatus ; prothorace elongate, antrorsum conspicue angustato, lateribus obliquis hand curvatis. Long. 10, lat. 5f m.'m. The male has the three basal joints of the front and middle tarsi distinctly incrassate, and furnished beneath with hairs bearing moderately large palettes, the claws of the front feet are elongate and but little curved, a little sinuate beneath and rather slender. This species though not much shining has the sculpture only slight, the usual subserial punctures being obsolete, the surface has however an excessively fine and minute reticulation which pi'events it being shining, and there is even a very slight sexual difference in this respect, the female being rather duller than the male. The species varies somewhat in colour, the individuals from Germany being darker than those from Lapland ; indeed in the examples from the former of these countries, the prothorax is generally quite infuscate, with the sides reddish. Northern Eiirojie, Siberia, (Sweden, Finland, North Germany). 807. 753. Agabus coxalis, n. sj). — (ia. — Ilybius suffusus, Crotch (No. 1473); North America. On Aquatic Carnivorous Coleoptera or Dytiscid(B. 551 and moi-e distinctly sinuate beneath ; on the liind foot of this sex the outer claw is shorter than the inner one, and has a more acuminate curved-down termination ; the apical ventral segment has an elevated carina along the middle on the hinder part, and is longitudinally plicate-rugose on each side. In the female the outer claw on the hind foot is greatly curved, and the apical ventral segment at the extremity is compressed in the middle, so that its extremity appears to bear a notch. The species is subject to a little variation in colour, being sometimes more piceous than black, and having the sides of the thorax and basal portion of the elytra more dilute in colour. It has only a very slight trace of an oeneous tint on its upper surface. Europe, (North America f), Sweden; Fiiiland to 63° 40', Sahlberg ; Britain, France, Germany, Lithuania). 837. 782. Dytiscus obscurus. Marsh., llyhius ohscurus, M.C. — Ovalis, convexus, niger, subtus piceus, antennis pedibusque quatuor anterioribus rufis, pedibus posterioribus piceis, supra sub-opacus densius reticulatus, reticulis ad elytrorum apicem obsoletis, elytris guttulis duabus pallidis ; coxis posterioribus evidenter reticulatis, margine anteriore externe parum curvato. Long. \\h, lat. 6 m.m. The male has the three basal joints of the front and middle tarsi distinctly incrassate and much compressed, and clothed beneath with rather long hairs bearing minute palettes ; on the front feet the anterior claw is not thickened but is distinctly emarginate beneath, while the hinder one is sliglitly more slender and more distinctly bi-emarginate, so that it has in the middle an excessively minute sharp proj ection ; the posterior claw on the middle feet has a tendency to assume a similar form, but is sometimes quite simple ; the outer claw of the hind tarsus is short, stout and quite obtuse at the apex ; the apical ventral segment has a carina on the middle of its hinder part, bub is but little rugose on each side ; the female has the ventral segment plicate-emarginate at the extremity, but so as generally to appear less emarginate than in Dytiscus ater, the outer claw of its hind foot is acuminate and curved at the extremity. This species is smaller than Dytiscus ater, (No. 781), and has the reticulation of the elytra more obsolete at the apex, it has no seneous tinge ; the male can be very easily distinguished from that sex of D. ater by the much less development of the hairs of the tarsi. It is more variable in form than D. ater, some individuals being a good deal more elongate than others. Ilybius sexdentatus, Schiodte, is one of the varieties of this species. Europe ; (Sweden ; Finland to 68°, Sahlberg; Britain, France, Germany). 832. 783. Ilybius subeeneus, Er., M.C. — Ovalis, convexus, baud elongatus, subtus piceus vel rufus, supra seneus, limbo anterius plus minusve ferrugineo, antennis 552 On Aquatic Carnivorous Coleoptera or Dytiscida. pedibusque rufis, supra subopacus, densius subtiliusque reticulatus, clytris guttulis duabus pallidis; coxis posterioribus margine extcriore exterue parum curvato. Long. Hi, lat. G m.m. The male has the three basal joints of the front and middle tarsi distinctly incrassate, and clothed beneath with rather long hairs which bear minute palettes ; the anterior claw of the front fe(3t is very nearly simple, while the posterior one has its basal portion emarginate beneath and slightly more bent ; the whole of the aj^ical portion of the last ventral segment is covered with coarse longitudinal strise, without any trace of central carina ; the outer claw of the hind foot is accuminate, and differs but little from the inner one except that it is much shorter : in the iemale the apical segment is plicate at the apex, and has the appearance of being rather deeply notched, and it has two or three rugae on each side. The species may be readily distinguished from Dytiscus obscurus by the metallic upper surfiice, and by its rather shorter form, as well as by the difl'erent male characters. It varies considerably in size and colour, and the individuals I have seen from North America seem to vary even more than those from Europe ; but I can find no definite characters to distinguish even the extremest specimens that have come under my observation. Europe; Arctic Siberia ; North Amei-ica. (Finland to 69°, Sahlberg ; Britain'?; France; Germany; Jenisei ; Hudson's Bay ; Canada). 839. 784. Ilybius pleuriticus, Lee, Agas. Lake 8up. p. 213. — Ovalis, elongatus, vix convexus, subtus piceus et sub-senescens, supra seneus, limbo anterius vage ferru- gineo, antennis pedibusque quatuor anterioribus rufis, pedibus posterioribus piceis, elytrorum epipleuris feriugineis; supra sub-opaciis, densius reticulatus, elytris guttulis duabus pallidis ; coxis posterioribus subtiliter strigosulis, margine anteriore externe haud subito curvato. Long. 12, lat. 6 m.m. The male has the three basal joints of the front and middle tarsi distinctly incrassate, and furnished beneath with long hairs which bear distinct rather large palettes, the anterior claws ai'e rather elongate and each is a little emarginate near the base; the outer claw on the hind foot is rather elongate and thickened, but is distinctly shorter than the inner one, its extremity is sub-obtuse, not at all curved ; the apical ventral segment has a short carina in the middle at the extremity, and is but little rugose on each side : the same segment in the female is plicate, and apj)ears to bear a rather deep narrow notch, and is quite without lateral rugosities. North America. 840. 785. Ilybius inversus, n. sp. — Ovalis, haud elongatus, convexus, subtus piceus et subsenescens, supra seneus, limbo anterius vage ferrugineo, antennis pedibusque quatuor anterioribus rufis, pedibus posterioribus piceis, elytrorum epipleuris ferru- On Aquatic Carnivorous Coleopteixt or Dj/tiscidce. 553 gineis ; supra subnitidus, crebvius vix subtiliter reticulatus, elytris guttulis duabus (quarum anteriore elongata et conspicua) testaceis ; coxis posterioribus subtiliter strigosulis, margine anteriore externa baud subito curvato. Long. 12^, lat. 6^ m.ni. The species difters from Iljbius pleuriticus, by its more convex less parallel form and the different reticulation of the upper surface. I have one mutilated individual only of the male before me, its sexual characters seem to be quite the same as in I. pleuriticus, but its hind feet being quite gone I cannot speak positively on this point ; the female has the apical notch broader than it is in I. pleuriticus. The form of the species makes it very similar to I. subseneus, but it is readily dis- tinguished therefrom by its more shining and coarser reticulated upper surface, and by the rather more slender outer portion of the metasternal wings. North America. 841. 786. Ilybius quadrimaculatus, .-\ube, M.C. — Ovalis, sat elongatus, minus convexus, subtus niger, supra nigro-ceneus, antetmis rufis, articulis 7-10 extrorsum infuscatis, pedibus piceis, elytris guttulis duabus te&taceis, epipleuris nigro-aeneis, supra sub- opacus, densius subtiliter reticulatus ; coxis posterioribus subtilius strigosulis et punctatis, margine anteriore externe baud abrupte curvato. Long. 11^, lat. 6 m.m. The male has three basal joints of the front and middle tarsi, distinctly incrassate, and furnished beneath with moderately long hairs, which bear small palettes ; of the front claws the anterior one is slightly thickened, and nearly straight beneath, while the hinder one is a good deal emarginate near the base ; on the hind feet the outer claw is nearly similar in form to the inner one, except that it is a good deal shorter ; the last ventral segment, has a much elevated carina on the middle of its apical portion, and is also coarsely rugose ; the female has the last segment also carinate, and appearing to bear only a very small notch, and is without rugosities. The species is of a more black colour than its near allies. North America. 842. 787. Ilybius crassus, Th., M.C. — Ovalis, baud elongatus, convexus, subtus nigri- cans, supra nigro-Eeneus, antennis pedibusque anterioribus rufis, posterioribus piceis ; elytris subopacis, densius reticulatis, punctis subseriatis conspicuis ; coxis posteri- oribus subtiliter strigosulis, margine anteriore extus sat abrupte curvato. Long. Hi, lat, 6 J m.m. The male has the basal joints of the front and middle tarsi a little incrassate, and furnished beneath with moderately long hairs bearing small palettes ; the claws o7^ the front feet are moderately long, and nearly simple, the hinder one being how- ever distinctly emarginate near the base ; the outer claw on the hind foot is thick- ened, and subobtuse at its apex, without any deflexed point ; the male has no 554 On Aquatic Carnivorous Coleoptera or DytiscidcB. carina on the last veutral segment, and is only indistinctly rugose on each side ; the female has the apical segment briefly plicate at the extremity, and forming a somewhat deep notch. This species should not be mistaken for I. subieneus, for its outline is diflferent, it being broadest behind the middle, the colour is darker, and the serial pnuctures of the elytra more distinct, and the outer claw on the male hind foot is different, and the anterior border of the hind coxa is more arched. It IS also readily distinguished from Dytiscus obscurus (No. 782), by a difference of outline, by its more brassy colour, and the quite distinct reticulation at the apex of the elytra, &c., &c. It approaches perhaps more nearly to I. quadrimacu- latus, but its form is moi-e convex, and broader behind the middle, the serial punctures of the elytra are more distinct, and the front border of the hind coxa approaches nearer to the middle coxa. Northern Europe. (Sweden and Finland to 67° 30' according to SaUberg.) 844. 7S8. Dytiscus guttiger, Gyll., Ib/biiis gnttiger, M.C. — Ovalis, fere angustus, sat convexus, subopacus, niger, antennis rufis, pedibus piceis, elytris densius subtiliter reticulatis, punctis subseriatis sat conspicuis, guttulis duabus parum conspicuis testaceis ; coxis posterioribus parcius obsolete strigosulis, margine anteriore extus minus abrupte deflexo ; prosterni processu apice elongato. Long. 9j, lat. 4| m.m. In the male the basal joints of the front and middle tarsi are a little incrassate, and are furnished beneath with moderately long hairs which bear minute palettes ; the claws on the front feet are not elongate, and are nearly simple, being slightly emarginate near the base ; on the hind feet the outer claw is a good deal shorter than the inner one, and is somewhat thickened, and has a quite obtuse extremity ; the male has a short carina on the last ventral segment, and no rugosities ; the female has the apex of the last ventral segment with a broad, but shallow emargination, and in the middle of it a thick short projection. Europe, (Sweden ; Finland to 63° 10', Sahlberg; Britain, France, Germany, Litliuania). 846. 789. Ilybius ignarus, Lee, M.C. — Ovalis, angustus, baud convexus, subopacus, niger, antennis rufis, pedibus piceis; elytris densius subtiliter reticulatis, punctis subseriatis sat conspicuis, guttulis duabus parum conspicuis testaceis ; coxis posterioribus parce subtiliter strigosulis, margine anteriore extus minus abrupte deflexo ; prosterni processu apice elongato. Long. 9, lat. 4f m.m. The male has the basal joints of the front and middle tarsi distinctly incrassate, and furnished beneath with moderately long hairs which bear minute palettes ; the front claws are moderately elongate and distinctly sinuate beneath ; on the hind feet, the outer claw is but little shorter than the inner one, and has a very minute. On Aquatic Caruivovo'ts Colcoptcva or Dyti'scidcB. 555 deflexed, acute apex ; the apical ventral segment bears a rather short carina, but no lateral rugosities. This species though excessively similar to Dytiscus guttiger, seems to differ by the more sinuate anterior claws of the male, and the less thickened and less obtuse outer claw of the hind foot, as well as by other slight distinctions. North America. 847. 790. Ilybius aenescens, Th. Op. Ent. II, p. 125. — Ovalis, hand elongatus, subde- pressus, fere opacus, subtus nigricans, prosterno elytrorumque epipleuris rufo- obscuris, supra feneus, capite anterius prothoracisque lateribus rufescentibus. antennis pedibusque rufis ; elytris densius subtiliter reticulatis, punctis subseriatis minus conspicuis, guttulisque duabus testaceis indistinctis ; coxis posterioribus obsoletissime strigosulis et punctatis, margins anteriore extus fere abrupte deflexo ; impressione metasternali minus elongate. Long. Sj, lat. 4| m.m. The male has the basal joints of the front and middle tarsi slightly incras.sate, and furnished beneath with moderately long hair.s bearing minute palettes; the anterior claws are simple ; on the hind feet the outer claw is but little shorter than the inner, and has a subacute apex ; the apical ventral segmunt has a very short carina at the ape.\', and no distinct rugosities ; in the female the last ventral segment bears a rather broad but not deep emargination, in the middle of which there is almost no projection. The species is excessively closely allied to Dytiscus guttiger (No. 788), but besides the slight differences in colour and sculpture, the sexual characters are also a little dissimilar. Northern Europe, Siberia ; (Sweden ; Finland, to (56° 30', Sahlberg ; Scotland, Belgium, France, Germany, Lithuania). 848. 791. Dytiscus angustior, GylL, Ilyhius unrjustior, M.C. — Ovalis, subdepressus, subopacus, niger, .supra seneus, antennis pedibusque rufis, illis articulis 7-10 ssepius extrorsum infuscatis, elytris densius .subtiliter reticulatis, punctis subseriatis minus conspicuis, guttulis duabus testaceis indistinctis ; coxis posterioribus sub- tiliter strigosulis, margiue anteriore externe leviter deflexo ; {irosterni processu apice miiuis vlongato. Long. 9i, lat. 5 m.m. The male has the basal joints of the front and middle tarsi a little incrassate and furnished beneath with niodorately long hairs which bear minute palettes ; the claws of the front feet are simjile : on the hind feet, the outer claw is shorter than the inner, and is obtusti at the extremity ; the apical ventral segment has a rather sharply elevated carina, and is rugose with elongate coarse striae. In the female the last ventral segment has an emargination at the apex, in the middle of which there is a coarse fold or plica. TBANS. ROV. DUB. SOC, >'.9 , VOL. U. ^ n 856 On Aquatic Carnivorous Coleoptera or Dijtiscidcp. The individuals from Eastern Siberia are a little smaller, less elongate in form, and have the reticulation of the upper surface rather finer than the type form from the Arctic regions ; the individual from Labrador is slightly larger and is nearly black, and has the reticulation of the surface not so dense. Northern Euioiie and Siberia ; Eastern Siberia ; Labrador, (Sweden ; Finland, to 69°, Sahlberg (ieruiany ; Siberia, Kantaika, Angara). 8t9. 792. Dysticus fuliginosus, Fab., Ihjhius fuliginosus, M.C. — Ovalis, fere angustus, sat convexus, subnitidus, rufo-testaceus, supra aneus, capite thoracisque lateribus plus minusve ferrugineis, elytris late testaceo-marginatis, margine ante apiceni obsoletescente; supra dcnsius subtiliusque reticulatus ; coxis posterioribus parcius obsoletiusque strigosulis, margine anteriore breviter et minus abrupte deflexo. Loner. 10, lat. o m.m. The male has the basal joints of the front and middle tarsi a good deal incrassate, and furnished beneath with long hairs, bearing narrow palettes ; the claws of the front feet are moderately elongate, and but little curved, the posterior one being rather broadly emarginate near the base ; on the hind feet, the outer claw differs from the inner very little, except that it is considerably shorter ; the last ventral segment has the apical portion covered with long though not very deep rugas, and has a short carina in the middle : the female has a large emargination at the apex of this segment, and in the middle a coarse prominence or short fold. The species varies a good deal in size ; and the yellow colour of the under surface and lateral margin of the elytra seems easily stained of a darker colour by decomposition of the contents of the body. Europe; North America ; (S>veden ; Finland to 64 , Sahlberg ; Britain, France, Germany). 851. 793. Ilybius meridionalis, Aub^, M.C. — Ovalis, baud angustus, sat convexus, subnitidus, subtus piceo-ferrugineus, supra ajneus, capite anterius, prothoracis lateribus elytrorumque margine (anterius late) ferrugineis, antennis testaceis, pedibus rufo-piceis ; supra densius subtiliusque reticulatus ; coxis posterioribus parcius obsoletiusque strigosulis, margine anteriore extus longius et sat abrujite deHexo. Long. 11, lat. G m.m. This species is broader than Dytiscus fuliginosus, and has the under surface generally darker, and the pale margin of the elytra less developed and less definite ; the sexual characteristics of the two sjaecies seem almost exactly the same ; although so similar in most respects, the two species can be readily and certainly distinguished by the greater development forwards of the hind coxaj in L meridi- onalis, so that the wings of the metasternum are more abbrevitited> especially in their outer portion. Sotithera Europe; Corsica; (France, Spain, Portugal, Italy). 852. On Aquatic Carnicorous Cokoptera or DytisidcB. 557 794. llybius limbatus, n. sp. — Minor, ovalis, sat convexus, tsubnitidus, testaceus, supra seneus, capite thoraceque plurf minusve pallescentibus, clytris margine lato testaceo ad apicem obsoletescente, dense punctato-reticulatis ; coxis posterioribus fere esculpturatis, marginu anteriore extus abrupte deflexo ; prosterni proctssu apice brevi. Long. 8, lat. 41 m.m. The male has the middle tarsi with the basal joints a little incrassate, and furnished beneath with moderately long hairs bearing minute palettes; on the hind feet the outer claw is considerably shorter than the inner one and has an acuminate extremity ; the apical ventral segment bears no carina, and has the hind margin somewhat obsoletely Tugose : the only individual I have seen of this sex has lost its front feet. The female has the last ventral segment almost simple. Eikstem Siberia. 83 -t. Gnoup 2. 795. llybius discedens, n. sp. — Ovalis, angustulus, sat convexus, sat nitidus, niger, antennis pedibusque anterioribus rufis, pedibus posterioribus piceis ; elytris ad basin densius parum perspiciie punctato-reticulatis. ad apicem j^unctulatis, punctis subseriatis conspicuis ; coxis posterioribus fere laevigatis ; prosterni processu satelongato; tarsis posterioribus articuHs tantum breviter lobatis. Long. Th-Sl m.m. lat. 4-4| m.m. The male has the front and middle tarsi almost simple and unincrassate ; the claws of the front feet are rather short, equal in length, the anterior rather dilated, with its lower edge nearly straight, the hinder one rather more slender, and with its basal portion distinctly emarginate beneath. The apical ventral seg- ment has its hinder part thin in the middle and smooth, but with some coarse striae on each side, its hind margin truncate or rather emarginate truncate : in the female this segment has a strong very short plica, and the appearance of a deep narrow notch at its apex. The claws (jf the hind feet are nearly similar in the two sexes, they are comparatively little unequal, still the outer is a good deal shorter than the inner, they are both rather slender and acuminate, and the outer one has its apex more curved than the other has, this is especially conspicuous in the female, the apical portion of the outer claw being in it strongly curved. The species is scarcely so large as I. guttiger, to Av^hich it has at first sight a resemblance : indeed superficially it suggests itself as a connecting link between Agabus and the smaller black Ilybii; it has a lateral and an apical yellow mark on each wing case; the hind coxce are not very large, and yet their front border is not very widely separated from the middle coxse. The swimming legs are feeble (for its genus) and tlie group of seta; on the femoral angle is very ill developed. North Anifriou, (Hudson's l>:iy). 'J'iO. 4 C » 558 On .iqinU/'c Carnlrorous Coleoplcra or DytiscldiE. 796. Ilybius obtusus, n. sp. — Ovalis, haud angustus, subdopressus, fere opacus, niger, supra nigro-subteneus, antennis crassiusculis rufis, articulo ultimo apice fusco, pedibus piceis; prothorace margine lateral! lato ; elytris deusius minus subtiliter reticulatis, et versus apicem fere punctatis, puuctis subseriatis magnis ; coxis posterioribus subobsolete reticulatis, margine anteriore minus cur%'ato; prosterni processu minus elongate. Long. 9f, lat. 5 m.ni. The female has a plica or fold in the middle of the apex of the last ventral segment, which does not project backwards at all. I have seen only a single individual of this species, which seems to be a very distinct one, only likely to be confounded with I. senescens, and Dytiscus angustior (Nos. 790 and 791), which ii resembles in size, and its little elongate prosternal process; but the nmch more conspicuous scul{)ture of the elytra will make the determination of this species very easy. Eastern Siberia. S.'JO. 797. Dytiscus biguttulus, Germ., Ins, sp. nov. p. 29. — Ovalis, fere brevis, convexus, subtus piceus, supra nigro-seneus, limbo anterius minus ferrugineo, elytrorum epipleuris ferrugineo-seneis, antennis pedibusque anterioribus rufis, pedibus posterioribus piceis ; supra sub-opacus, elytris densius subtiliusque reticulatis, guttulis duabus pallidis, quarum posteriore conspicua ; cuxis posteriori- bus subtiliter strigosulis et punctatis, margine anteriore extus alinipte curvato ; jjrosterni processu elongate. Long. 9\, lat. oj m.m. The male has the basal joints of the front and middle tarsi a little incrassate, and furnished beneath with moderately long hairs which bear small palettes ; the claws of the front feet are not elongate, the anterior one is very slightly, the hinder rather deeply, emarginate near the base ; on the hind feet the outer claw is acuminate, and differs only slightly from the inner, except in its length ; the ajjical ventral segment, has a rather short carina along the middle of its apical portion, and its hind margin is only obscurely rugose from a slight elongation of the punctures wliich it bears ; the female has the apex of the last segment, with a short plica, and a rather broad short apical emargination, and is smooth at the sides, This species is shorter in form than any of the three preceding; and is smaller than L subasneus No. (789), and has the front border of the hind coxte more abruptly defle.xed at its outer part. It greatly resembles I. oblitus (Nc. 801), but is distinguished by the less approximation of the front border of the hind coxce to the middle coxal cavity. North America. 843. 798. Ilybius similis, Th., M.C — Ovalis, convexus, niger, subtus nigro-piceus, antennis pedibusque quatuor anterioribus rufis, pedibus posterioribus rufo-plceis, On Aquatic Carnivorous Colcoptera or DytisciJce. 559 supra subopacus, densius reticulatus ; elytris guttulis duabus pallidis, ad apicem parum siiniato acuminatis ; coxis posterioribus evidenter reticulatis, maro-ine anterioie externe parum curvato. Long. lOi, lat. G ni.m. This species is excessively similar to Dytiscus obscurus (No. 7S2), but the male claws are slightly different ; on its hind feet the outer claw is more slender and rather longer, and has a minute deflexed sharp extremity ; while on the front feet the anterior claw is a little thickened near the base, and appears scarcely sinuate beneath, and the posterior claws are without the minute projection in the middle of its hind margin : the apical ventral segment is deeply rugose on each side : the female is very difficult to distinguish from D. obscurus, but the apex of the elytra is less sinuate, and the reticulation there is not quite so obsolete. Europe, (Sweden; France, Limoges; Germaiij'). 9:^8. 799. Ilybius laramaeus, Lee, M.C. — Ovalis, angustulus, baud brevis, sat convexus, subtus piceus, supra nigro-seneus, limbo anterius ferrugineo, antennis pedibusque anterioribus rufis, pedibus posterioribus piceis ; supra subopacus, elytris densius reticulatis, guttulis duabus pallidis quarum posteriore conspicua ; coxis posterioribus subtiliter strigosulis, raargine anteriore extus abrupte curvato, prosterni jjrocessu elongato. Long. 10, lat. 5i m.m. I have only a single immature individual of this species before me ; it is a male and its sexual characters seem to be just the same as those of Dytiscus biguttulus (No. 797), but the form is so much narrower that I think it will prove to be a distinct species. North Americca. 929. 800. Ilybius confusus, Aube, M.C. — (Immaturus) ; Ovalis, sat convexus, baud elongatus, ferruginous, supra posterius tenescens, crebrius subtiliter reticulatus, elytris guttulis duabus pallidis, coxis posterioribus crebrius reticulatis, margine anteriore extus abrupte curvatis. Long. 11|, lat. 6l m.m. The male has the basal joints of the front and middle tarsi a little dilated and furnished beneath with moderately long hairs, bearing small palettes ; the claws of the front feet are nearly simple, the hinder one however being emarofinate near the base, on the hind feet the outer claw differs but little from the inner one except that it is distinctly shorter. The apical ventral segment is quite destitute of carina or rugosities. I have seen of this species only one male (from Dejean's collection) very immature and in very bad condition. 1 should think the species will prove to be most allied to I. inversus, (No. 785), but it has the coxte more densely and distinctly .sculptured and the last ventral segment of the male without carina : and the front border of the hind coxa has its outer part rather more abruptly deflexed. North America. (Coll. de Bonvouloir, ex mus. Dejean). 845. 560 On Aquatic Carnivorous Cokopicra or Di/liscidie. SOI. Ilybius oblitus, n. sp. — Ovalis, fere brevis, convexus, subtus pieeus, supra uigro-ieneus, limbo anterius minus ferrugineo, antennis pedibusque rufis ; supra subopacus, elytris densius roticulatis, guttulis duabus, quarum posteriore conspicua, pallidis ; coxis posterioribus crebre evidenterque strigosulis, margine anteriore ad coxam intermediani approximato extus abrupte longeque deflexo ; prosterni processu brevi. Long. \0h, lat. 6 m.m. The male has the basal joints of the front and middle tarsi distinctly incras?ate, and furnished beneath with rather long hairs, which bear distinct palettes, the claws of the front feet are elongate and sinuate, the hinder one of the two especially is slender and much sinuate ; on the hind feet tlie outer claw is elongate, slender and very acuminate, similar in fact to that of the female ; the last ventral segment is almost without carina or rugosities ; in the female the same segment is, com- paratively witli i). biguttulus (No. 797), but little deflexed-emarginate at ihe extremity. Though singularly similar to Dytiscus biguttulus this species is readily dis- tinguished therefrom by the greater approximation of the front border of the hind coxa to the middle coxal cavity. North America. 856. 802. Dytiscus fenestratus, Fab., lUjhius t'enesfratus, M.C. — Ovalis, convexus, ferriigineus, supra reneus, limbo ferrugineo, supra subnitidus, densius reticulatus, elytris ad medium versus latera guttula elongata testacea ; coxis posterioribus fere esculpturatis, margine anteriore ad coxam intermediani approximato, cxtus per- abrupte longeque deflexo; prosterni processu fere brevi. Long. Hi, lat. 6 m.m. The male has the basal joints of tlie front aiid middle tarsi distinctly incrassate, and furnished beneath with long hairs bearing distinct palettes ; the claws of the front feet are long, the anterior one being thickened beneath except on the outer portion which is very acuminate, the hinder one is not quite so long, and is slender and subsinuate ; the outer claw on the hind feet is thickened, subobtuse, and considerably shorter than the inner one ; the last vontral segment has the hinder part rugose, with a strongly elevated carina in the middle ; in the female the hinder part of this segment is very deeply deflexed-emarginate. Colymbetes prescotti, Mann. (Ilybius prescotti, Aube), is a red variety of this species found in the north. Europe, (Sweden ; Finlaad to 60" lO'Sahlberg; Brituiu ; France; Germany.) 857. 803. Ilybiuscinctus(Sharp), n. sp. — Minor, ovalis, subnitidus, testaceus, supra seneus, oapite anterius thoraceque ad latera ferrugineis, elytris margine lato ad apicem triha- mato testacco, densius subtiliusque punctato-reticulatis ; coxis posterioribus fere On Aquatic Carnivorous Coleoplera or Di/tiscidce. 561 esculpturatis, marginu antei'iore extus abrupte minus longe deflexo ; prosterni j^rocessu apice sat elongate. Long. 8, lat. i ra.m. The male has the basal joints of tlie front and middle tarsi a little incrassate, and furnished beneath with rather short hairs bearing minute palettes ; the claws of the front feet are rather short, and the anterior one rather strongly curved ; there is only a very slight difference between the two claws on the hind feet, the outer being scarcely at all shorter than the inner one, the apical ventral segment is with- out carina or rugte. I have before me only one extremely immature male individual of this very in- teresting .species, the claws of the hind tarsi completing the connexion in -this respect with the genus Agabus. It is in size, colour and form extremely similar to 1. limbatus (No. 794), and in respect to the structure of its coxce and prosternal pro- cess connects it with Dytiscus fuliginosus (No. 792), the wings of the metasternum being decidedly a little less abbreviate than in D. fuliginosus. Centra] Asia, (Yauglii-hissar). 853. 804. Ilybius apicalis, Sharp, Tr. Ent. Soc. Lond. 1873, p. 51. — Ovalis, sat con- vexus, sat nitidus, rufus, supra a?neus, limbo late ferrugineo ad apicem trihamato ; supra densius subtiliusque reticulatus ; pedibus posterioribus brevibus et crassis, coxis valde elongatis, fere esculpturatis, margine anteriore extus abnipte longiusque deflexo. Long. 9, lat. 3f m.m. The male has the basal joints of the IVont and middle tarsi a little incrassate, and furnished beneath with rather short hairs, which bear small palettes; the claws on the front feet are short, and the anterior one rather strongly curved ; the outer claw on the hind feet differs little from the inner one, except that it is distinctly shorter ; the last ventral segment is simple in both sexes. This species is in respect of its hind legs the most highly developed of the Ilybii, and by its large hind coxse approximates to Coptotomus ; the presternum has the longitudinal ridge along its middle not so acute as in the other Ilybii. Japan. 855. Unassoci.\ted Genera. (Nos. 54 to 60). The following seven genera are not sutficiently accoi'dant inter ae to justify their establishment as a natural group ; but they may readily be recognized by the following negative characters. They none of them possess the group of ciliee at the angle of the posterior femur, such as exists in the Agabini ; and they do not possess the stigmatic rugoe of the Colynibetiui ; and their individuals are nearly always inferior in stature to those of the latter group. .^lO'H On Aquatic Carnivorouf! Coleoptcra or Di/dscidu; The seven genera may be readily distinguished as follows : — Coxal incision distinct ; upper sur- | face with sculpture. American. J Coxal incision wantiui; ; upper sur- (^ face without sculptui-e. Asiatic, j VCT3 a a '> '^ • J fe 1 Co.Kal lines obliterated. •^ -S -^ *3 a ti Oj CJ ^ •5"^ J tn >-> '^ -a — T a> 5 ^ s J o 05 :i i: X s o >,S " ^ ? ^ > F "3 3^^ Coxal lines SI'B present. |g§ ^ 5'S -" ^ >- o ^ s *j -a :3 --w u 0 0 — Coxal border verv broad. Upper surface with sculpture ; thorax without lateral margin ; prosternum not sulcate. Prosternum lonffitudinally sulcate alon" the middle. ^4 f Coxal lines veiy closi; to one another : \ I prosternum but little incrassate I- ^ , . , along the middle. I Coxal border I very narrow. ' ri i r n i- 4. *. ^ Coxiil lines normally distant ; pro- | sternum much incrassate along the }■ middle. J I'Vont border of hind coxa but little arched, wing of metasternum rather large, not linear, not deflexed outside coxa. AGYLMDUS. ( Vide p. 596.) LAC'coyEcrrs. (Tic/Bp. ."598.) AGA BETES (r,W?p. 599.) MAT US. (Vide p. 599.) COI'ELATUS. ( Vide below.) COPTOTOMUS. (CiWep. GOl.) LANCETES. ( Vide p. 6U2.) I. 54.— Genus COPELATUS. Coxal lines extremely close to one another, especially in their hinder portions, where just before their abrupt divergence to form the borders of the coxal processes they are very nearly contiguous with the central line forming the suture of the two 00X03 ; at the anterior part of the coxal processes they become excessively hue so that they can with difficulty be perceived, and are abruptly diverted outwards at right angles to tlieir former course. The species ary numerous"'' and are found in nearly all the warmer parts of the world ; the sculpture of the elytra which frequently consists of elongate striae offers a ready method of arranging them in fourteen groups ; seven of these groups possess in addition to the conspicuous regular stria), a short additional stria placed * In addition to those enumerated in the succeeding text, it is prolmble that the following should be referred to the genu.s. Colymbetes bimaculatus, Perrond (No. 1216)?group I; New Caledonia. — Copelatus angustatus, Chev. (No. 1258) near No. 882; Cuba. — Copelatus australiw, Clark, (No. 1259) near No. 815; Australia. — Copelatus basalis. Boh. (No. 1260); Caffraria. — Copelatus elongatulus, Macl. (No. 1261) near No. 808 ; Australia. — Copelatus externus, Kiisch, No. 1262); Peru. — Copelatus forniosus, WoU. (No. 1263); Africa aid Cape Verde Islands. — Copelatus gallapagoensis, Wat. (No. 1264) near No. 875 ; Galapagos Islands. — Copelatus normalis, Er. (No. 1265) : Peru. — Copelatus obtusus, Boh. (No. 1266); Caffraria. -Copelatus quadrisignatns, Regt. (No. 1167); Manilla. — Copelatus striatellus, Boh. (No. 1268^1 Cartiaria. — Cojielatus striaticollis, Luc. (No. 1260); Si iu(h America. — Copelatus substriatus, Kirsch, (No. 1270); Peru. — Copelatus undecimstriatus, Aubc, (No. 1271); Cayeune.—Dytiscus bicolor, Fab. (No. 1286) ; Africa. Si a B On Aquatic Carnivorous Colcoptera or Dytiscidce. very near the outside of the wing-case quite close to the irregular the epipleural margin, this I have called "submarginal stria"; length, sometimes very short. and without any entire strise, . ..•••' but with either t'lree, four, or five true striae on each wing-case, with six striaj on each wing-case, "S \ with eight striw on each wing-case, . witli ten strife on each wing-case, with eleven stride on each wing-case, . witli twelve strise on each wing-case, . with two other stiia; on each wing-case, with five other strise on each, . . with six other stria; on each, with seven or eight other stria; on each, . with nine or ten other stri;e on each, with eleven other strise on each, with twelve other stria; on each, 563 punctures near it is of variable To 3 a Groi pi. Nos. 805 to 827. 2. Nos. 828 to 836. 3. No. 837. 4. Nos. 838, 839. 5. Nos. 840 to 845. 6. No. 846. 7. No. 847. 8. No. 848. 9. Nos. 849, 850. 10. Nos. 851 to 864. 11. Nos. 865 to 868. 12. Nos. 869 to 886. 13. Nos. 887 to »95. 14. No. 896. Group 1. (Nus. 805 to 827). Elytra without submai-giual stria, and without any entire striae. This group is a composite one, containing many different forms some of which will probably prove to be different genera. No. 806 appears to have the middle 00X86 absolutely contiguous, while in the other species they are separated. No. 827 I have placed in this section, the male being without stripe, but the female has seven or eight very fine stri«. 805. Copelatus filiformis, n. sp. — (<^) Elongatus, angustus, parallelus, subnitidus, testaceus, prothorace elytrisque infuscatis, limbo elytrorumque basi testaceis ; antennis elongatis tenuibus ; elytris striis duabus interruptis, obsoletis, lineolisque subtilibus, sparsis, ornatis. Long. 41, lat. if m.m. This is a very distinct species, resembling Celina australis, Clark (No. 803,) but with the male front and middle tarsi strongly dilated, and but little compressed. The very fine scratches on the elytra have a slightly oblique direction. \ have seen only one individual. Himalaya, (Coll. Wehncke). 717. TRANS. BOr. DCB. SOC, N.S., VOL. II. 4 D 564 (Jit, Aquatic Carnivorous Coleoptera or Dytiscidce. 806. Celina australis, Clk., M.C. — Oblongus, angustulus, elongatus, parallelus, depressus, minus nitidus, ferrugineus, elytris abdomineque piceis, illis lateribus dilutioribus ; prothorace elytrisque fere eequaliter breviter strigulosis, his seriebus duabus punctorun distinctis, . strigulis ad. apiceiQ obliquis. Long. 5|, lat. vix. 1h m.m. The few specimens I have seen of this distinct species seem to be all females. The peculiar parallel elongate form, and the distinct, regularly distributed short fine strife, or scratches, of the upper surface separate it at once from the other Australian s^^ecies. Australia, (Melbourne, Rockhampton). 667. 807. Copelatus hydroporoides, n. sp. — Tn:-?}?., Oblongo-ovalis, baud elongatus, .sub- depressus, minus nitidus, ferrugineus, plus miuusve infuscatus, prothoracis lateribus elytrorumque basi dilutioribus, capite sat conspicue punctulato ; jn'othorace medio late sub]a3vigato, ad angulos posteriores punctato; elyi;ris crebre, oequaliter forti- terque punctatis. Long. 5, lat. 2^ m.m. I have seen only a single female, in bad condition, of this very distinct species ; it bears a good deal of resemblance to the European Hydroporus ferrugineus, (No. 636). New Caledonia. 684. 808. Copelatus gracilis, n. s}).— Oblongo-ovalis, angustulus, sat parallelus, sub- depressus, ferrugineus, elytris abdomineque castaneis, illis basi dilutiore, antennis pedibusque testaceis ; elytris seriebus tribus punctorum, preetereaque parce subtil- issime punctatis. Long. 4, lat. 2 m.m. The male differs from the female only by a very slight thickening of the front and middle tar?i. Australia, (Rockhampton). 6G1. 809. Copelatus victorioe, Clk., M.C. — Ovalis, angustulus, minus dcpressus, baud parallelus, pone medium evldenter latior, ferrugineus, elytris testaceis, pectore abdomineque nigricantibus, elytris seriebus tribus punctorum sat distinctis, versus apiccm sine strigulis transvcrsis distinctis. Long. 4^, lat. 21 m.m. The male is distinguished from the female only by a slight thickening of the front and middle tarsi. The species is readily dii^tinguished from C. gracilis by the differences in form and colour. Australia, (Melbourne). GG2. On Aquatic Carnivorous Coleoptera or Dytiscidoe. 5G5 810. Copelatus ferrugineus, n. sp. — Ovalis, angustulus, minus depressus, vix parallelus, feiTugineus, elytris testaceis ; elytris seriebus punctorum sat distinctis, et versus apicem strigulis transversis distinctis ; prothorace ad angulos posteriores punctis strigulosis parcis. Long. 4i, lat. 2^ m.m. The male has the front and middle tarsi a little dilated. The species is very closely allied to C victorijB, but is a little larger ; the most important difference seems to be the distinctness of the transverse scratches on the hind part of the elytra. Australia, (Port Denison). 6G3. 811. Copelatus lividus, n. sp. — Ovalis, angustulus, elongatus, minus depressus, ferrugineus, elytris testaceis, abdomine pectoreque nigris; elytris seriebus punctoruai sat distinctis, versus apicem strigulis transversis distinctis ; prothorace ad angulos posteriores punctis strigulosis paucis. Long. 51, lat. 21 m.m. The male has the front and middle tarsi a little dilated. The species is very closely allied to the three preceding, but is larger than any of them. Australia, (Adelaide, Melbourne). G64. 812. Copelatus labratus, n. sp. — Fern., Ovalis, angustulus, elongatus, minus depressus, piceus, capite prothoracisque lateribus plus minusve dilutioribus, antennis pedibusque testaceis ; prothorace ad latera strigulis brevibus crebribus, disco latius Isevigato, medio brevissime canaliculato ; elytris seriebus punctorum sat distinctis, crebrius punctulatis, sed ad latera in medio baud conspicue longitu- dinaliter strigulosis. Long, b^, lat. 2| m.m. I have seen only females of this species which differs from those following by its smaller size, and by the much diminished development of the short longitudinal impressions on the upper surface. Australia, (Melbourne, Victoria). CG5. 813. Copelatus simplex, Clk., M.C.- — Ovalis, angustus, elongatus, niger, capite anterius prothoracisque lateribus rufis, elytris versus latera dilutioribus, antennis pedibusque testaceis ; elytris seriebus punctorum minus distinctis, obsolete punctu- latis, in femina (cumque thorace) latius longitudinaliter strigulosis. Long. 5^, lat. 2| m.m. The male has the front and middle tar.si moderately dilated, and the anterior claw on the front feet is thicker than the posterior, but a little before the apex becomes rather suddenly slender ; the female has the sides of the thorax broadly, 1 D '2 ij66 On Aquatic Carnivorous Colcoptcra or Di/tincidce. as well as the basal portion of the elytra, covered with regular, fine, short, distinct longitudinal impressions. Australia and Tasmania, (Melbourne). G66. 814. Copelatus ater, n. sp. — Ovalis, minus angustus, subdepressus, niger, capite thoraceque ad angulos anteriores piceo-rufis, antennis pedibusque rufis ; prothorace ad latera subtilissime strigoso-punctato ; elytris crebre evidenter punctatis, seriebus punctorum sub-distinctis ; coxis posterioribus fortiter crebreque strigosis. Long. 7i, lat. 3a m.m. The male has the front and middle tarsi a good deal dilated ; the anterior claw of the front foot is thicker than the other, and is straight beneath, and has an extremely short, slender termination ; there is no difterence in the sculpture of the two sexes, except that the female has the strigose punctuation at the sides of the thorax just perceptibly more distinct. The species is about the size of the European D;)i;iscus agilis (No. 825), but is broader and less parallel ; of all the Copelati it is the species most resembling an Agabus by the superficial characters of colour, form, and sculpture. Australia, (Swan River, K. George Sound). 6G8. 815. Copelatus extensus, n. sp. — Fern., Oblongo-ovalis, elongatus, niger, thorace ad latera picescente, antennis pedibusque rufis ; elytris seriebus punctorum distinctis, absque strigulis ; coxis posterioribus strigulis crebribus profundis. Long. 10, lat. 4| m.m. There are only a very few insignificant scratches on the thorax, and none at all on the elvtra. I have only seen a single individual : though it much resembles at first sight C. acuductus (No. 819), it is very distinct therefrom by the sculpture of the thorax and elytra. Aiistralia, (Brisbane). G60, , 816. Copelatus maculatus (Wehncke), n, sp. — Fcm., Oblongo-ovalis, elongatus, sat depressus, minus nitidus, niger, prothoracis lateribus picescentibus, elytris apice rufo-maculatis, antennis pedibusque rufis ; capite crebre evidenter punctato ; thorace medio Isevigato, versus latera strigulis omnium brevissimis parcioribus ; elytris strigulis brevissimis numerosis undique fere cequaliter ornatis. Long. 6^, lat. 31 m.m. I have seen only a single, very mutilated, individual of the female sex. New Caledonk. 083. On Aquatic Carnivorous Cokoptcra or Dijdscidce. 567 817. Copelatus melanarius, n. sp. — Oblongo-ovalis, baud parallelus, niger, capite anterius prothoraceque ad latera rufesceutibus, antennis pedibusque rufis ; thorace adlatera latius subtilissime striguloso-punctato; elytris scriebus punctorum distinetis, in mare fere sine strigulis, in femina ad latera strigulis subtilissimis densis plus minusve extensis ; coxis posterioribus crebre subtiliter strigulosis. Long. 9, lat. 4i m.m. The male has the front and middle tarsi dilated ; and the anterior claw of the front foot is slightly thickened and bisinuate beneath, the apical portion being more slender than the rest : in the female there are on the sides of the elytra near the middle some very dense and fine scratches which are variable in their extent. The species varies somewhat in size and sculpture; there are sometimes a few scratches in the male on the basal jiortion of the elytra between the first, second, and third series of punctures. In a small narrow vaiiety from Clarence River, the elytra of the female are covered with the dense fine scratches over a great extent, only the ajiex and a narrow space along the suture being free from them. Austi-alia, (Clarence River). G70. 818. Copelatus nigritulus, n, sp. — Oblongo-ovalis, minus depressus, niger, nitidus, capite anterius prothoraceque ad latera rufesceutibus, antennis pedibusque rufis ; prothorace singulis brevibus sparsis conspicuis ; elytris seriebus punctorum minus distinetis, strigulis brevibus, minus subtilibus, sat numerosis, ad apicem omnino desinentibus ; coxis posterioribus strigulis crebribus profundis. Long. 8 J, lat. 4 m.m. The male has the frout and mi'ldle tarsi dilated, and the anterior claw of the front feet stouter but with a slender terminal portion. In the female the scratches on the elytra are slightly finer than in the male, and in some specimens their number is increased. The specimens before me show a great deal of variation especially as to the de- velopment and extent of the sculpture of the upper surface. The above diagnosis represents the majoi-ity of individuals, but certain forms have quite as extensive a development of the sculpture, as is found in C. acuductus. It is very probable that it may ultimately prove there is a series of closely allied species of this group. Australia, Tasmania. G71. 819. Copelatus acuductus, Clk., M.C. — Oblongo-ovalis, minus depressus, elon- gatus, capite prothoraceque anterius versus latera picescentibus, antennis pedibusque rufis ; prothorace strigulis brevibus conspicuis ; elytris fere sine seriebus punctorum, strigulis brevibus rudis numerosis, posterius subtiliorilms, ct longius versus apicem extensis. Long. 10, lat. 4-2 m.m. 568 On Aquatic Caridvorous Coleoptera or Vytiscidw. The male lias the front and middle tarsi dilated, and the claws of the front feet nearly simple : there is no evident diiference in the sculpture of the sexes. I have separated this from the numerous forms I have considered as being C. nigritulu!?, chiefly on account of the less dilated male tarsi, and the simple front claws. Australia, (Melbourne). 672. 820. Copelatus subjectus, n. sp. — Ovalis, .sat angustus et elongatus, subde- pressus, nigricans, elytris piceis, prothoracis lateribus elytrorumque basi dilutioribus, antennis pedibusque rufis ; capite crebre subtilius punctulato ; prothorace sublsBvi ; elytris seriebus punctorum tribus vol quatuor distinctis. Long. 6, lat. vix 3 m.m. In this species there are on the elytra two very distinct series of punctures, and between them is another series less distinct because the punctures composing it are much fewer in number, i.e. placed at a greater distance from one another ; there is also a more external series which is less regular and distinct. I have seen only two individuals of this species, and suspect they are males, though the tarsi are scarcely perceptibly thickened. New Caledonia. 673. 821. Colymbetes parvulus, Boisd., Agahus pavculus, M.C. — Ublongo-ovalis, baud elongatus, sat depressus, subopacus, fusco-rufus, anterius dilutior, antennis pedi- busque testaceis ; elytris seriebus punctorum obsoletis. Long. 4^, lat. 2j- m.m. This little species has the upper surface less shining than usual, owing to its being very finely reticulate or coriaceous ; other sculpture is nearly absent. The sexes are difficult to distinguish, there being only a slightly greater development of the front and middle tarsi in the male. Hawaiian Islands. 074. 822. Copelatus politus, n. sp. — Oblongo-ovalis, depressus, pernitidus, fere laevis, piceus, sujjra magis nigricans, antennis ped:bu.sque rufis; fere lasvigatus. Long. 4, lat. 2 m.m. The male has the front and middle tarsi very little dilated, but the intermediate joints of the antennae are broad and flattened, the third joint very strongly so, and the three following ones to a gradually diminished extent. New Guinea, (Hatam, July, 1875, Dr. Beccari). 660. 823. Copelatus insolitus, Chev., M.C. — Oblongus, sat angustus, subdepressus, nitidus, testaceus, prothorace medio late infuscato, elytris fusco-testaceis basi On Aquatic Carnivorous Coleoptcra or Di/tiscida. 569 apiceque pallidis, abdoinine pectoreque rufesceutibus ; elytvis seriebus tribns sub- tilibus punctorum. Long. 5, lat. 2^ m.m. The male has the front and middle tarsi a good deal dilated, and its front tibite are slender, with their upper part curved and on the inside broadly but little deeply emarginate below the knee. The female is unknown to me. The smooth surface, with not very distinct series of punctures on the elytra, after the manner so common in Hydroporus, renders the species very easy to distinguish. Cuba, St. Domingo. Go8. 824. Co2:)elatus inornatus, n. sp. — Ovalis, latiusculus, subdepressus, nitidulus, laevis, niger, prothorace versus angulos anteriores piceo, antennis pedibusque rufo- testaceis; elytris seriebus tribus punctorum subtilissimorum. Long. 7, lat. 3'8- m.m. The male has the front and middle tarsi moderately dilated, and the front tibia; simple. I have not seen the other sex. The species seems allied to Copelatus ater, (No. 814), but the upper surface is smooth, not punctulate as in that sj^ecies. South Aujerica ? I am uot at all sure that this locality will prove to be the correct habitat for this r. Trail). GIO. 576 Oji Aquatic C'lruicorous Co!e iptcia or Di/ttsciche. S43. Copelatusalternatus, n. sp. — Ovalis, subdejjressus, angustulus, iiitidus, piceiis, capite, pi-othoracis lateribus elytrisque ca>;taneis, his basi diluiiore ; thorace strigulis numerosis distinctis it- qualiter distribiitis ; elytris striis decern baud subtilibus, alternis evidenter brevioribus. Lonw. G, lat. 2| m.m. In the male the front and middle tarsi ai'c moderately dilated, the front tibiae are rather stout, and very indistinctly emarginate below the knee. In the female the upper surface bears rather numerous very fine punctures which are not to be observed in the male. The females show a good deal of variation in the prothoracic scratches, these in the individuals from PetropoHs being finer and loss numerous than in the specimens from other localities; I have seen but a single male and four females. South America, (Brazil). 039. 844. Copelatus dupoiiti, Aube, M.C. — Ovalis, subdepressus, nitidus, subtus rufo- piceus, supi'a rufescens, prothorace medio late nigricante, elytris lateribus fasciaque lata transversa pone medium nigris ; prothorace strigulis parcis distinctis sed brevi- bus ; elytris striis decern subtilibus, quarum secunda quam ceteris versus apicem paulo brevior, antennis pedibusque rufis. Long. Gf, lat. Ss m.m. In this species the elytra are of an obscure yellowish or reddish colour, with a dark mark extending along the side but not reaching the extremity, this mark is broader near the shoulder, and beyond the middle is connected with a dark mark which extends inwards but does not reach the suture. In the male the front and middle tarsi are moderately dilated, tlie front tibiae are i-ather stout and simple. In the female the sides of the thorax bear numerous dense fine stria», in addition to those that are distributed over the rest of the surface. South America, (Cayenne, PetropoHs, Deer., 1850, R. F. Sahlberg.) 638. 845. Copelatus bonvouloiri, n. sp. — Fern., Robustus, ovalis, sat latus et elougatus, nitidus, niger, capite, prothoracis lateribus anguste, elytroj'um basi et apice, antennis pedibusque rufis, corpore subtus piceo ; prothorace undique dense strigoso ; elytris striis decern subtilibus, alternis (proesertim secunda) brevioribus. Long. 7, Int. 3| m.m. Readily distinguished amongst its allies by the very dense and distinct ocratches on the thorax and by its large size : the red colour at the base of the elytra is not extensive and therefore not very striking, on the other hand the yellowish apex is very conspicuous. 1 have seen only a single specimen. South America, (Brazil, Sta, Catherina, coll. Bonvouloir.) G47. On Aquatic Carnivorous Coleoptera or DijtiscidcB. 577 Gkol'p G. (No. 840). Elytra without submarginal stria, but with eleven strise on each. The strise in this species are very perfect. 84G. Copelatus nigrolineatus, n. sp. — Ovalis, sat angustus, subdepressus, supra testaceus, prothorace medio late fusco, elytris sordide testaceis basi lateribusque dilutioribus, corpore subtus ferrugineo: elytris striis undecim elongatis, tribus internis anterius obsoletis. Long. 5i, lat. 2f m.ni. The elytra in this species have eleven equidistant lines, of which the three internal become so fine as to disappear before reaching the base, all the lines extend nearly to the apex, but some, notably the first and outer one, are a little shorter than the others, there is no trace of a marginal stria. The male has the front and middle tarsi a little dilated, the front tibioe simple, 'i'here are no sexual disparities in the sculpture. Australia, (Champion. Bay, Carpentaria, Port Denison, Port Boweii). 677. Group 7. (No. 847). Elytra without submarginal strise but with about twelve other strise on each, •which however are more or less broken or irregular. The ver}' peculiar species I have thus isolated might almost have been placed among the species destitute of true stripe, for the deep lines on its elytra are much broken and irregular; nevertheless as it is not closely allied to any species of the group destitute of true strise and as moreover the linear arrangement of the broken strise is quite conspicuous ia spite of their irregularity, I have placed it amongst the striate groups. 847. Copelatus interruptus, n. sp. — Ovalis, angustulus, sat depressus, picescens, prothorace ad angulos anteriores diiutiore, elytris piceo-testaceis, antennis pedibus- que sordide testaceis; capite prothoraceque obsolete punctulatis ; elytris striis undecim vel duodecim conspicuis sed disintegratis. Long. G, lat. 3 m.m. This species is very easily distinguished by the peculiar, broken-up stria3 of the elytra. The male has the front and middle tar^i a little incrassate; the only female I have seen has the striae of the elytra finer and still more broken-up than they are in the male. It is possible, but not clear to me, that this may be the Agabus interruptus Perroud, (see description No. l,U>-2). New CaleJonia. (581. ^''8 On Aquatic Carnivorous Coleoptera or DytiscidcB. Group 8. (No. 848). Elytra with a subinarginal stria, and two other striae on each. The striae present in this species are those which, if the complement were com- plete, would be the sixth and tenth. 848. Copelatus capensis, (Chev.) n. sp. — Suboblongus, sat depressus, elongatus, nitidus, nigricans, capite anterius prothoraceque versus angulos anteriores plus minusvc dilute rufescentibus, antennis pedibusque testaceis ; elytris versus latera striis duabus elongatis, alteraque marginali valde abbreviata, et in disco stria (juartaplus rainusve interrupta et obsoletescente ; prosterno in medio altc conipresso- carinato. Long. 7, lat. 3i m.m. The male differs from the female by its slightly dilated tarsi, and the form of the front tibiae which are curved at the base, and are on the inner edge bisinuate on their basal portion. Caffraria, (Adoo Buh^li). G89. Group 9. (Nos. 849 and 850). Elytra with a submarginal stria and five other striae on each. The two species although agreeing in the striation of the elytra are probably not really allied to one another. 849. Copelatus dorias, n. sp. — Fern., Elongatus, angustulus, subparallelus, minus nitidus, subtus rufo-piceus, abdomine piece, supra piceo-niger, capite, prothoracis lateribus clytrorumque basi lateribus et apice dilutioribus ; antennis pedibusque testaceis ; elytris striis quinque elongatis, P ad 4"° fere tequalibus, quinto paulo breviore, striaque marginali anterius valde abbreviata ; supra punctulatus, et in prothorace elytrisque strigulis brevissimis numerosis ; prosterno in medio fortiter compresso-elevato. Long. 5i, lat. £2 m.m. This is a very distinct species, of which I have seen but a single female : the first stria is remote from the suture ; the numerous very short scratches on the elytra are absent at the apex, and replaced by some distant punctures. Borneo, (Sarawak; found by the MurquLs G. Doria in 18G5 or "07). 709. .On Aquatic Carnivorous Coleoptcra or Dytiscidce. 579 850. Copelatiis debilis, n. sp. — Ovalis, depressus, nltidus, piceo-testaceus, capite, prothorace lateribus, elytrorum basi et apice, antennis pedibusque testaceis ; elytris striis quinque elongatig, prima a sutura remota, striaque marginal! anterius ab- breviata. Lonff. 4. lat. 2 m.m. The male has the front and middle tarsi a good deal dilated, the front tibite are much curved inwardly and the basal portion slender : the upper surface is very smooth except for the strise on the wing-cases : the female differs a little from the male, the striae being slightly deeper, and there being a very fine and obsolete punctuation on the upper surface, but no scratches. The species is of small size and cannot be very easily mistaken for any other, on account of the number of the striae — five on eacli winof-case: the first of these is quite twice as far from the suture as it is from the second stria ; then the three inner interstices are of about the one width, the fourth, or outer one, being a little narrower than the others ; the submarginal stria is elongate, but stops short a good deal behind the shoulder. Central America, (Cliontales, Belt; S. Gerouimo, Guatemala, Champion). 1158. Group 10. (Nos. 851 to 864). Elytra with a submarginal stria and six other striae on each. In this group the strife are equidistant, and it is the n.lternate ones that are wanting ; very frequently the first stria is much abbreviated in front, or indeed only exists on the posterior portion of the wing-case. 551. Copelatus marginatus (Wehncke), n. sp. — Ovalis, latiusculus, hand elongatus, subdepressus, piceus, capite et prothoracis elytrorumque lateribus dilutioribus, antennis pedibusque testaceis ; prothorace sublaevigato, ad angulos posteriores subtilius punctulato ; elytris striis sex ad apicem prolongatis, interna posterius tantum exstat, ceteris elongatis, aliaque marginali valde abbreviata. Long. 6, lat. Z\ m.m. In the male the front and middle tarsi are a good deal dilated ; the basal portion of the front tibia is quite slender, and its inner edge sinuate, the lower part of the tibia is broad ; the elytra have a subobsolete punctuation, which in the female is replaced by the numei'ous very short and extremely fine scratches. Australia, (Rockhamptoii, Port Deuison). G75. THANS. EOT. DUB. SOC. X.3., VOL. II. 4 F 580 071 Aquatic Carnivorouji Colcoptera or Dytiscidce. 852. Copelatus striatulus, Aubd, M.C. — Oblongo-ovalis, sat angustus, subde- pressus, sat nitidus, piceus, elytris nigricautibus, antennis pedibusque rufis; fere impunctatus ; elytris striis quinque elongatis, stria marginali valde abbreviata, aliaque suturali versus apicem tan turn exstante; prosterno medio alte carinato com- presso. Long. 5i, lat. 2f m.m. A single female in my own collection agrees exactly with the type (in very bad condition) of this species from Chevrolat's collection in the Brussels Museum. Africa, (Senegal). 690. 853. Copelatus latipes, n. sp. — Oblongo-ovalis, latiusculus, subdepressus, sat nitidus, piceus, elytris nigricautibus, antennis pedibusque rufis; subtiliter punctatus, prothorace ad latera sat fortiter punctato; elytris striis quinque elongatis, stria marginali valde abbreviata, aliaque suturali ad apicem tantum exstante; prosterno medio mediocriter compresso-carinato. Long. 6, lat. 3i m.m. The male has the front and middle tarsi rather broadly dilated; the front tibiae are very abruptly bent below the knee, the basal part being slender and bisinuate on the inner edge, while the apical portion is broad. The female I do not know. Malacca. 691. 854. Copelatus pusillus, n. sp. — Oblongo-ovalis, sat elongatus, angustulus, subde- pressus, piceus, supra magis nigricans, marginibus (prsesertim elytrorum lateribus) dilutioribus, antennis pedibusque rufo-testaceis; obsolete punctatus, prothorace ad latera ante angulos posteriores area parva strigulosa; elytris striis subtilibus sex, aliaque marginali brevissima, striis prima et externa anterius desinentibus. Long. 4i, lat. 2t m.m. The male has the front and middle tarsi somewhat broadly dilated, the front tibiae are curved, the basal portion being very slender, and much emarginate below the knee: the female shows no difference in sculpture from the male. Siam, (Bangjjok). 692. 855. Copelatus fuscipennis, n. sp. — i^em.,Ovalis,vix angustus, subdepressus, nitidus subtus rufescens, supra fuscescens, capite, prothoracis lateribus elytrorumque basi rufis, harum apice, antennis pedibusque testaceis; fere Itevigatus, prothorace versus latera strigulis parcissimis brevissimisque; elytris striis sex sat profundis et fere integris, aliaque marginali brevissima. Long. 5, lat, 2| m.m. The very few scattered and distant scratches on the thorax are inconspicuous, sometimes in fact nearly entirely absent, the striae on the elytra ai"e all continued nearly to the base, the internal and the outer ones being only very slightly On Aquatic Carnivorous Coleoplera or Dytiscida. 581 abbreviated there ; at the base thore may be seen between the strife some short marks or scratches representing rudimentary intermediate strise. In this species the lateral part of the wing-case is darker than the other parts. T have seen only the female. Celebes. 693. 8oG. Colymbetes lineatus, Guer., M.C. — Fern., Ovalis, sat angustus et elongatus, piceus, supra nigricans, capite prothoracisque lateribus dilutioribus, elytris ad apicera testaceo-maculatis, antennis pedibusque rufis ; prothorace ad latera area parva strigulosa ; elytris striis sex sat profundis et fere integris, aliaque marginali brevissima. Long. 5§, lat. 3 m.m. The only individual I have seen is a typical specimen from Dejean's collection, it is a female. The species appears to be closely allied to Copelatus fuscipennis, but is more elongate in form, and darker in colour, and instead of having a few distant scratches on the thorax, has at the sides a small patch of crowded scratches. Amboyna. 707. 857. Copelatus gentilis,n.sp. — Fe7n., Ovalis, baud angustus, subdepressus, nitidus, subtilissime punctulatus, nigricans, antennis, pedibus, capite, prothoracis lateribus eh'trorumque basi rufis, his apice testaceis ; prothorace lateribus ante angulos posteriores area parva strigulosa; elytris striis sex, integris, minus subtilibus, aliaque marginali abbreviata. Long. 5|, lat. 3 m.m. I have seen but a single female. Though closely allied to Copelatus fuscipennis, this is undoubtedly a distinct species, being larger and darker, and having the prostemal process considerably larger. Batchiau, (Wallace). 694. 858. Copelatus geniculatus, n. sp. — Mas, Ovalis, vix latus, subdepressus, nitidus, piceus, supra nigricans, capite anterius prothoraceque ad angulos anteriores fufescentibus, elytris ante apicem sat discrete rufo-maculatis, antennis pedibusque rufis ; subloevigatus, prothorace ante angulos posteriores strigulis paucissimis ; elytris striis sex integris, inter se fere sequaliter distantibus, aliaque marginali abbreviata. Long. 6, lat. os m.m. In the male the front and middle tarsi are much dilated, and the front tibite ai'e comparatively slender and are greatly curved at the base, and not very distinctly bisinuate inwardl3^ Malay Archipelago. 706. 4 F 2 582 On Aquatic Carnivorous Coleoptcra or Dytiscidce. 859. Copelatus oblitus, n. sp. — Oblongo-ovalis, nee angustus neque elongatus sat depressus, subnitidus, obsolete punctatus, rufescens, thorace ulytrisque nigricantibns, illis lat.eribus, harum basi et lateribus rufis ; prothoracu ad latera ipsa angustius striguloso ; elytris striis sex sat subtilibu.s integris, (sutuiali basi desinente) aliaque margiiiali brevissima ; coxis posterioribus subtiliter aciculatis. Long. 44, lat. 2i ni.in. The male has the front and middle tarsi moderately dilateJ, the front tibiae a little curved at the base, and rather broadly eoiarginate on the inner edge below the knee. I have seen but a singfle individual. 'O" Singapore. C95. 860. Copelatus indicus, n. sp.- — Oblongo-ovalis, baud elongatus, sat latus, minus nitidus, ferrugineus, supra picescens, prothoracis elytrorumque lateribus ferrugineis; capite subtiliter punctulato; prothorace subtilius punctalato, ad latera anguste striguloso; elytris striis sex integris, profundis, aliaque marginali valde abbreviata; coxis posterioribus breviter sed rude aciculatis. Long. Si, lat. 21 m.m. The male has the front and middle tarsi a good deal dilated, the front tibia; are curved at the base, and on their inner edge are bisinuate ; in the female the basal portion of the elytra bears between the striaa numerous, very distinct anastomosing lines ; these become scanty and less extensive towards the sutural portion and are altogether wanting close to the suture. India. 690. 86L Copelatus discoideus, n. sp. — Ovalis, latiusculus, subdepressus, ferrugineus, abdomine, capite thoraceque nigricantibns, elytris testaceis, plaga magna discoidali nigra, capite anterius prothoraceque ad latera ferrugineis ; capite subtiliter sed evidenter punctato ; thorace ad latera punctato-strigoso ; elytris striis sex integris sat profundis, suturali multo subtiliore, aliaque marginali brevissima; coxis posteriori- bus indistincte aciculatis. Long. 5| , lat. 3 m.m. The male has the front and middle tarsi broadly dilated, the front tibice much curved at the base, the basal portion being slender and bisinuate on the inner edge ; the female differs only by its simple tarsi and tibiae. Mesopotamia. 697. 862. Copelatus strigulosus, n. sp. — Fern., Ov^alis, latiusculus, sat elongatus, piceus, capite anterius prothoraceque ad latera dilutioribus, elytris ad apicem (vix ad basin) antennis pedibusque testaceis ; thorace ad latera et basi utrinque densissime striguloso ; elytris lineis anastomozantibus undique excepte in partem quintam On Aquatic Carnivorous Coleoptera or Di/tiscidce. 5^3 apicalem tectis, striisque sex in partem apicalem sat profuiidis sed inter lineas anastomozantes obsoletescentibus. Long. 6, lat. 3i ni.m. Though allied to Copelatus discoidens, this species in the female sex (which is the only one I know), is readily distinguished by the great extent of the dark colour on the elytra, by its rather more elongate oval form, by the scratched' surface of the elytra, and by the entire absence of the marginal stria. Mesopotamia. G98. 863. Copelatus africanus, n. sp. — Ovalis, sat elongatus, vix angustulus, sat depressus, piceus, capite anterius prothoracis elytrorumque lateribus ferrugineis, antennis pedibusque rufis ; capite subtiliter pimctulato ; prothorace ad latera distinctius punctato ; elytris striis sex integris (sutui'ali anterius desinente) profundis, aliaque marginali valde abbreviata. Long. Gi, lat. 82 m.m. I have seen but a single male individual of this species which has lost most ot its tarsi, the front ones appear to be moderately dilated, and the front tibia is rather broad, and a little curved at the knee. Africa, (N' Garni). C99. 864. Copelatus pulchellus, Klug, M.C. — Oblongo-ovalis, latiusculus, baud elongatus, subdepressus, piceus, capite anterius, prothoracis lateribus elytrisque rufescentibus, his disco plus minusve infuscato, basi discrete dilutiore, antennis pedibusque rufis ; thorace ad angulos posteriores strigoso-punctato ; elytris striis sex profundis, suturali prope scutellum desinente, aliaque marginali valde abbreviata. Long. 5§, lat. Si m.m. The male has the front and middle tarsi a good deal dilated, and the front tibite a good deal curved, the basal portion being rather deeply bisinuate inwardly, the lower part of the tibia is broad : the female has a very few, not easily detected, scratches about the middle of the elytra. Though Aub<^ states that this species occurs in Senegal as well as in Bourbon, I am inclined to think that the few specimens (in very bad condition) which I have seen from the former locality indicate one or two distinct allied species : I have also seen in the Brussels Mus. collection a specimen of a variety or closely allied species said to be from Cuba, and have another in my own possession said to be from N. America, but I consider confirmation is wanted of these localities. I may add that I am not quite sure that K lug's description of C. pulchellus really refers to this species. Bourbon. (? Senegal). 700. •584 On Aquatic Carnivorous Coleoptera or Dijtiscidce. Groitp 11. (Nos. 865 to 868). Elytra with a submarginal stria and with seven or eight other striie on each. The striae absent are those neur the suture, but although the species agree fairly in this respect, it is pretty certain they are not really allied to one another ; No. 867 indeed seems by the nature of the coxal lines to approximate to C. australis of the first or estriate group; and No. 868 is more probably allied to No. 848 (eighth group). 865. Copelatus chevrolati, Aube, M.C. — Oralis, elongatus, subdepressus, subtu.s nigro-piceus, capite thoraceque rufescentibus, hoc lateribus dilutioribus, elytris magis castaneis ; prothorace fere Isevi (in femina ad latera subtiliter strigoso) ; elytris striis octo subtilibus, alternis posterius abbreviatis, aliaque marginali anterius abbreviata. Long. 6, lat. 31 m.m. The male has the front and middle tarsi a good deal dilated, the front tibite nearly simple ; the female has the sides of the thorax covered over a broad space ■with fine anastomosing striae. North America. (California, Ai-izona, Texas, Kansas, Lake Superior, sfec. Crotch). 043. • 866. Copelatus validus, n. sp. — Oblongo-ovalis, sat latus, depressus, nitidus, niger, antennis pedibusque rufis, prothorace lateribus elytrorumque apice dilutioribus ; elvtris striis octo ante apicem desinentibus, prima a sutura remota, secunda disin- teorata, aliaque marginali anterius et posterius abbreviata. Long. Tj', lat. 4 m.m. I have seen but a single individual ; it is a female, and has the sides of the thorax rather densely covered with elongate scratches, but the disc is quite smooth ; a rather small area near the side of each wing case also is rather closely covered with distinct scratches. This species seems to be a large and dark-coloured one ; the first stria is about as far from the suture as the width of the first, second, third, and fourth interstices too-ether ; the second sti'ia is disintegrated and rudimentary, the second, fourth and sixth are considerably shorter than the others, and stop short about two-thirds of the length of the wing cases, the first, third, fifth, seventh and eighth are longer, but still stop short a good distance before the apex ; at the base the alternate striaj are more or less abbreviated : the submarginal stria is short and placed about the middle of the length. Central America, (Chontales, T. Belt). 1159. On Aquatic Carnivorous Coleopter:i or DytiscidcB. 585 867. Copelatus clarki (Welmcke), n. sp. — Ovalis, elongatus, sat depressus piceus, capite prothoracisque lateribus dilutioribus, antennis pedibusque testaceis ; elytris striis pluriinis (clrciter septera) posterius abbreviatis, alternis subtilioribus et versus apiceiu brevioribus, alia^ue margmali brevissima. Long. 7, lat. Si m.m. In this species the first stria is remote from the suture, and the other strias are narrowly separated from one another, the interval between the first and second being however double that between the others, because the intervening stria is absent, or is represented only by some widely separated linear marks. The male has the front and middle tarsi greatly dilated, the front tibise slightly curved at the base, so that the l;asal portion is a little more slender and is slightly sinuate internally. The sculpture does not differ in the sexes. Australia, (Cape Yoi-k). G76. 868. Copelatus carinatus, n. sp. — Fern., Oblongo-ovalis, vix angustulus vel elon- gatus, minus depressus, sat nitidus, piceus, supra nigro piceus, capite et pro thoracis elytrorumque lateribus dilutioribus, antennis pedibusque rufis; prothorace strigulis subtilissimis paucis ; elytris striis octo subtilibus, interna a sutura remota, 2% 4^ 6*que posterius multo brevioribus ; striaque marginali brevissima ; prosterno in medio alte compi-esso-carinato. Long. 7, lat, 3t m.m. The strice of the elytra are rather peculiar in this species, there are eight distinct fine striaj on each wing-case the first of which is placed far from the suture ; between it and the suture there is however, quite at the base, the commencement of another stria ; the 2nd, 4th, and 6th striae are much shorter behind than the others, while the 7th is obsolete in front. I have seen only a single individual. Africa, (Guin^e Portugaise, coll. Bonvouloir). 705. Group 12. (Nos. 869 to 886). Elytra with a submarginal stria and nine or ten other striae on each. In Nos. 869 and 870, the second stria is nearly or altogether wanting, and the first is much abbreviate at the base ; in the other species the ten striae are present, but some of them (especially the internal ones) may be more or less abbreviate at the base. 869. Copelatus prolongatus, n. sp. — Robustus, ovalis, sat latus et elongatus, nitidior, niger, capite piceo, prothorace lateribus anguste ferrugineis, elytris apice sordide testaceo ; antennis pedibusque rufis ; prothorace maris fare laevigato. 586 On Aquatic Carnivorous Coleoptera or Dyliscidce. feminse ad latera crebrius latiusque striguloso ; elytris striis duabus suturalibus anterius longe desinentibus, octo subtilibus ad apice fere prolongatis (alternis brevioribus), aliaque marginali anterius valde abbreviata. Long. 7i, lat. 3| m.m. The male has the front and middle tarsi broadly dilated, and the front tibiae simple, and the thorax almost without sculpture (except the marginal series) : the female has the sides of the thorax covered over a rather broad space with fine but quite distinct scratches or strife. The species has the second .stria from the suture indicated only by some small interrupted remnants, the first stria is less obliterated. I have seen only a single pair. Panama. G44. 870. Copelatus nigricans, n. sp. — Eobustus,. ovalis, latus, nitidior, niger, capite piceo, prothorace lateribus anguste ferrugineis, elytris apice sordide testaceo, antenuis pedibusque rufis, corpore subtus piceo; prothorace feminre ad latera striguloso; elytris striis duabus suturalibus anterius longe desinentibus, octo ad apice fere prolongatis (alternis brevioribus), aliaque marginali anterius valde abbreviata. Long. 71, lat. 4 m.m. 1 have seen but one individual, which is a female; besides the scratches on the thorax there are numerous very distinct scratches on the sides of the elytra, not extending to the base or apex. The species is closely allied to Copelatus prolongatus but is much broader. Soiith America, (New Granada, coll. de Bonvouloir). C4.5. 87L Copelatus vigintistriatus, Fairm., Ann. Soc. Ent. Fr. 1869, p. 188. — Oblongo- ovalis, angustulus, sat depressus, piceus, capite thorace elytrorumque lateribus dilutioribus, antennis pedibusque rufis ; prothorace subloevigato, strigulis brevissimis per-paucis ; elytris striis decem sat profundis, suturali anterius, alternis posterius, brevioribus, aliaque marginali brevissima. Long. .51, lat. 2* m.m. I have seen only the female of this species. JNIadagascar. 702. 872. Copelatus polystrigus, n. sp. — Ovalis, sat angustus, subdepressus, nitidus, nif'ropiceus, elytris vitta intra -laterali cum macula ante-apicali fere conjuncta testacea, prothoracis lateribus dilutioribus, antennis pedibusque rufis ; prothorace sublaevigato, strigulis brevissimis per-paucis ; elytris striis decem profundis, alternis posterius brevioribus, aliaque marginali valde abbreviata. Long. 6, lat. 3 m.m. I have seen only females of this species. The individuals from Senegal have a fascia of a red colour at the base of the elytra which is scarcely to be seen in On Aquatic- Carnivorous Coleoptera or Dijtiscidce. 587 tlie individuals from Madagascar : but I cannot at present find other marks to distinguish them. \n some individuals the internal stria of the elytra becomes obsolete in front. Madagascar ; Senegal. 703. 873. Copelatus erichsoni, Guer., M.C. — Ovalis, hand angustus, subdepressus, nitidus, piceo-rufus, thorace elytrisque nigricantibus, ilio versus angulos anteriores rufescente, his fascia basali, et vitta intra-laterali cum macula ante-apicali fere conjuncta, testaceis, antennis pedibusque vufis; thorace strigulis brevibus numerosis; eljtris striis decern pei'-profundis alternis posterius paulo brevioribus, aliaque mar- ginali valde abbreviata. Long. 61, lat. 3i m.m. The male has the front and middle tarsi a little dilated, and the front tibiae a little curved at the base, and a little bisinuate internally below the knee ; the female does not depart in sculpture from the male. The species is closely allied to Copelatus polystrigus, but is. readily distinguislied by the greater scul^^ture of the thorax, and the very deep striae of the elytra. Abyssinia. 704. 874. Copelatus obscurus, n. sp. — Ovalis, subdejoressus, piceus, capite, prothorace elytrorumque apice dilutioribus, antennis pedibusque rufis ; prothorace strigulis subtilioribus brevioribusque, in disco Isevigato ; elytris striis decem sat suibtlibus, 2° quam ceteris paulo brevioribus, aliaque marginali anterius abbreviata. Long. 5i, lat. 2? m.m. This species is closely allied to Dytiscus postieatus (No. 875), but is smaller than its smallest forms, and has the scratches of the thorax more reduced ; on the other hand the alternate strise of the elytra are less abbreviate behind, and the colour seems more obscure ; though on this latter point I do not feel very sure as I have seen but a single female in rather bad condition : there are no ti'aces of anv fine scratches on the elytra of this species. Amazons, (Eio Sappo, foniul in Wiiter standing in a canoe by Prof. TraUl, "Jlst November, 1874). 637. 875. Dytiscus postieatus. Fab., Copelatus postieatus, M.C. — Ovalis, subdepressus, nitidus, piceus, capite piceo-rufo, prothoracis lateribus elytrorumque basi ferrugineis, his apice (sajpiusque macula laterali) dilutioro vel rufescente ; prothorace strigulis distinctis sat numerosis fere asqualiter distributis ; elytris striis decem sat subtilibus, alternis posterius evidentcr abbreviatis, 2" quam ceteris brevioribus, aliaque marginali, anterius abbreviata. Long. C, lat. o m.m. The male has the front and middle tarsi distinctly dilated, the front tibiaj are TBANS. ROY. DUB. SOC, N.S., VOL. 11. 4 G oSS On Aquatic Carnivorou.s Coleoptcva or Dyliscidce. rather broad and simple. Tlie species includes numerous forms or varieties, but the material before me does not justify me in considering them as distinct species. The female has sometimes the greater part of the elytra and the thorax at the sides covered with very fine anastomosing strife, which in other specimens arc quite wanting, and various intermediate gradations occur. The size also varies a good deal, as does also the colour, the largest form found in Central A merica and Mexico (C. signatus, Sharp) having the red marks of the elytra pale and distinct. The scratches on the thorax also vary somewhat in number and depth: and the stria> of the elytra ure also variable in depth. I have considered as the type of the species the form occuring in the Antilles, which was the one to which Fabricius gave the name Dytiscus posticatus. Antilles, (Cuba, Guadelopc) ; Mexico; Central America; Cayenne; Brazil. 63G. 876. Copelatus terminalis, n. sp. — Ovalis, latus, depressus, nitidus, subtus rufo- testaceus, supra nigrican.s, capite, prothorace ad latera,elytris basi et apice(s£Bpiusque macula laterali),antennis pedibusquetestaceis; prothorace strigulisbrevibus impressis ; elytris striis decern subtilibus, alternis posterius abbrcviatis, aliaque marginali brevissima. Lonfj. Gi, lat. 31 m.m. The male has the front and middle tarsi distinctly dilated, and the front tibice broad and simple; it has the thorax scattered over with short linear punctures, which become obsolete towards the sides, in the female these punctures are more elongate, and are more developed near the side than they are on the middle. The striaj of the wing-cases are quite regular at the base, the first is a little more distant from the suture than it is from the second, and is carried on nearer to the tipex than any of the others are, the alternate ones are distinctly shorter than the others, and nearly of one length ; the submarginal stria is very short, and placed ■nearly entirely behind the middle. The distinct yellow marks on the elytra are variable, besides the spot near the side (on the 8th and 9th interstices) there is generally another on the .5th interstice, and this may become elongate and connected with the basal band. The species is very similar to a variety of Dytiscus posticatus, which resembles it in markings, (C. signatus. Sharp), but C. terminalis is broader, the strife of the elytra are finer, and the alternate ones, (especifdly thii second), arc less abbreviate behind. Central America, (S. Geroniino, and El Jicaro, Vera Paz, Guatemala; Champion). 1102. 877. Copelatus depressus, n. sp. — Oblongo-ovalis, paruni latus, depressus, subtus rufo-testaceus, abdomine fuscescetite, supra fusco-piceus, caj^ite, prothorace late ad latera, elytris basi apiceque testaceis, antennis pedibusque testaceis ; elytris striis Oil Aquatic Carnivorous Colcoptera or Di/iiscidce. 589 decern ante ajncem abbreviatis, alternis brevioribus et ad basin plus minusve abbreviatis et disintegratis, striaque marginali brevissima. Long. 6, lat. 3i m.m. I have not seen the male of this species ; the female has the thorax densely covered with elongate scratches, which however are absent from the disc ; there are also a few very fine scratches on the back of the head ; near the outside of the elytron, about the middle, there is an elongate area covered rather densely with very fine scratches. The strife on the wing-cases in this species are rather fine, and the inner one is nearly as near to the suture as it is to the second stria ; they are more or less abbreviated and broken up at the base, especially the second and fourth, while the third, fifth, seventh, ninth and tenth, reach very nearly to the base; none of the striae extend to near the apex, but leave nearly one-sixth of the length free, and the alternate ones are considerably shorter than this ; the submarginal stria is extremely short and fine, and may easily be overlooked. Central America, (S. Geronimo. Guatemala, Champion). 1160. 878. Copelatus impressicollis, n. sp. — Oblongo-ovalis, angustulus, parum con- vexus, fusco-niger, capite thoraceque sordide testaceis, supra fuscis, hoc lateribus, elytris basi, antennis pedibusque testaceis ; elytris striis decem sat profundis, ad apicem paulo abbreviatis, (alternis brevioribus), aliaque marginali valde abbreviata. Long. 5h, lat. 2'i m.m. The male has the front and middle tarsi much dilated, and the front tibi. 631.) 606 On Aquatic Carnivorous Coleopte)-a or Dytiscidce. I. (ii. —Genus SCUTOPTERU.S. Side pieces of the fourth and following ventral segments coaiparatively broad, that of the fourth segment being only about twice as long as broad. Upper suiface reticulate, black in colour. The two species are North American. • 918. Agabus angustus, Lee, Scutopterus angustus, M.C. — Suboblongus, parum convexus, vix nitidus, nigro-piceus, auteunis palpisque piceo-rutis, pedibus piceis, caj^ite anterius anguste rufescente, in medio verticis macula jjarva, prothoracis marginibus vage picescentibus ; prothorace basi subtruncato ; corpore supra (in elytris profundius) reticulato, elytris punctis seriatis tantum anterius sat conspicuis. Long. 16, lat. 8 m.m. The male has the three basal joints of the front and middle tarsi much dilated and scarcely compressed, and furnished beneath with four series of palettes, and with a large basal patch of glandular puhe.scence, their fourth joint is also dilated auil short, the claws are simple and rather short : the anterior tibiae have a deep emargination on their inner edge a little below the knee, tlie female I have not seen The species is very di.stinct by a number of chai-acters, from 8. horni ; it is of rather narrower and more depressed form, and less intensely black in colour and less shining ; the reticulation on the elytra ioi-ms smaller meshes, and the serial punctures are less distinct especially behind ; the thorax shows a sharper lateral margin ; the antennae are rather more slender and elongate ; the hind coxae are rather larger, but their anterior border is less arched, the wings of the metasteruum are considei'ably larger, and the hind legs are more elongate and slender. North America, (Lake Superior, Kansas, Canada ; fide Crotch). 927. 919. Scutopterus horni. Crotch, Tr. Am. Ent. Soc. IV, p. 40.5. — Suboblongus, niger, nitidus, antennis palpisque ruhs, pedibus piceis, capite ad angulos clypei et in medio verticis parum discrete rufescente ; prothorace basi subtruncato ; corpore supra, (in elytris profundius) reticulato, elytris punctis seriatis etiam ad apicem conspicuis. Long. 16, lat. 8 m.m. The male has the three basal joints of the front and middle tarsi much dilated, and scarcely at all compressed, and furnished beneath with four series of palettes, and with a large basal patch of glandular pubescence, their fourth joint is also dilated and short, the claws are simple and rather short ; the anterior tibiae have a deep emargination on their inner edge a little below the knee. The female On Aquatic Carnivorous Coleoptera or Dytiscidce. 607 resembles the male in sculpture : it has no cilias on the outer edge of the hind tarsi beneath, whereas in the male, both sides of the tarsi are ciliate. North America, (Hudson's Bay). 11G5. I. 62.— Genus RHANTUS. Side piece of fourth and following ventral segments very narrow ; metasternal groove distinct and well defined ; terminal joint of hind tarsus not longer, (or but little longer) than the preceding one; thorax nearly always margined; colour of "wing-cases frequently yellow speckled with black. This genus as known to me comprises about forty species* ; there are but few parts of the world where it is not represented by one or more species. They are difficult to determine, and I cannot at present arrange them in natural groups that would make the task more easy. 920. Colymbetes paeificus, Boisd., M.C. — OvaUs, minus convexus et elongatus, nigricans, vix nitidus, sublcevigatus, subtilissime punctulatus, nullo modo reticula- tus, nigricans, vertice rufo-bimaculato, prothoraeis lateribus rufis, elytris nigro rufoque vermiculatis, punctis seriatis magnis; antennis pedibusque rufis, pedibus posterioribus picescentibus; prosterno in medio minus incrassato, processu brevi, sat compresso; unguiculis posterioribus longitudine parum dissimilibus. Long. 9f, lat. 5 m.m. The male characters are very slight, the basal joints of the front and middle tarsi being a little incrassate, and furnished beneath with four series of extremely rudimentary palettes. The claws are rather short, simple, and equal. This very interesting species has the outei- claw of the hind foot just visibly * The following uames should probably also be assigned to the genus : — Colymbetes assimilis, Kirb, (No. 1,213); North America. — Colymbetes darwinii, Bab. (No. 1,219), near No. 926; Patagonia. — Coljanbetes discicollis, Aube (No. l,221)? = No. 924; Java. — Colymbetes di.stigma, BruUe (No. 1,223), gen. dub. ; South America. — Colymbetes dujjonti, Aube (No. 1,225), near No. 92G; South America. — Colymbetes fonticola, Phil. (No. 1,226); near No. 926 ; Chili.— Colymbetes gutticollis. Say. (No. 1,230) ?No. 935 Var. ; Mexico. — Colymbetes interclusus, Walk. (No. 1,234-) ; Ceylon. — Colymbetes marmoratus, Perroud, (No. 1,239), gen. dub.; New Caledonia. — Colymbetes obsciu-icollis, Aubii (No. 1,241^ ?nearNo. 926; Chill — Colymbetes socialis, Wat. (No. 1,250) ; Rodriguez Island. — Colymbetes suturalis, Macl. (No. l,254)'?=No. 1,221; Java.— Colymbetes vibicicollis, Hoch. (No. 1,257) '«=No.924; Caucasus.— Hydaticus riehli, Wehncke (No. 1,320) ; Cuba. — Rhantus (?) consimilis, Motsch. (No. 1,500) 1 near No. 944 ; California. — Rhantus flavo-griseus. Crotch (No. 1,501) near No. 935 ; North America. — Rhantus luteicollis, Gebl. (No. 1,502), near No. 951 ; Siberia. — Rhantus nigriventris, Motsch. (No. 1,503), near No. 924 ; Kamtschatka. — Rhantus nigropunctatus, Motsch. (No. 1,504 ; near No. 954) ; Songoria. 608 071 Aquatic Carnivorous Coleoptera or DytiscidcE. shorter than the inner one, and its extremity a little more slender and more curved. The two individuals before me are from diflferent sources; one was recently collected by Mr. Blackburn, the other was formerly in Dejean's collection; they differ in size and minor details, and may very probably prove to be two distinct species. Sandwich Islands. 8G9. 921. Rhantus debilis, n. sp. — Ovalis, hand elongatus, depressus, nitidus, supra subtiliter reticulatus, nigricans, capite anterius et in vertice thoraceque rufescentibus, hoc disco infuscato, elytris nigro testaceoque vermiculatis ; prosterno anterius parum elevato, processu brevi, vix compresso, metasterni lateribus brevibus; tarsis posterioribus unguiculo externo quam interne fere duplo breviore. Long. 8, lat. vix 4 m.m. The male has the basal joints of the trout and middle tarsi slightly incrassate, compressed, and furnished beneath with four rows of narrow palettes ; the claws of the front feet are rather short, strongly curved, the anterior one slightly longer than the other. Tahiti. 871. 922. Rhantus annectens, n. sp. — Ovalis, baud elongatus, subdepressus, nitidus, subltevigatus, omnium subtilissime reticulatus, pectore abdomineque nigris, supra rufescens, capite in medio prothoracisque macula discoidali nigricantibus, elytris nigro testaceoque vermiculatis ; prosterno piceo, medio minus alte elevato, processu sat elongate, minus compresso. Long. 11, lat. 5 m.m. The male has the basal joints of the front and middle tarsi a little incrassate, and compressed, and furnished beneath with four rows of narrow palettes. I have seen only two very mutilated individuals ; the species approximates to Colymbetes pulverosus, Steph., but is rather smaller, and the black marks on the elytra are larger, and form tortuous markings rather than spots : the prosternal process is a little shorter and less compressed, and the front border of the hind coxse approaches nearer to the middle coxae. Navigators Islands. 872. 923. Rhantus plantaris, n. sp. — Ovalis, sat elongatus, angustulus, nitidus, sub- Isevigatus, subtilissime punctulatus, nullo mode reticulatus, testaceus, pectore, abdomine et capite utrinque ad oculos nigris, elytris nigro-irrorati.s, punctis seriatis conspicuis ; prosterno in medio minus elevato, processu sat elongate, parum com- On Aquntic Carnivorous Coleoptera or DijtiscidxB. 609 presso; metasterni lateribus brevibus; tarsis posteiioribus elongatis, unguiculis valde insequalibus. Long. 10, lat. 5 m.m. The male has the front tarsi rather broadly dilated, and not compressed, the fourth joint being triangular; they are clothed beneath with four series of narrow palettes, and on the basal portion wdth short setae ; their claws are rather short and stout, and strongly curved, the front one being rather shorter than the hind one; the middle tarsi are also dilated and clothed like the front feet, their fifth joint is elongate, but the claws are wanting in the only specimen known. The female is unknown. New Zealand, (Dunedin, Castlenau). 870. 924. Colymbetes pulverosus, Steph., RJiantus jyulverosus, M.C. — Ovalis, hand convexus, nitidus, subtus niger, prosterni processu plus minusve dilutiore, antennis pedibusque anterioribus testaceis, pedibus posterioribus piceis, supra testaceus, vertice nigro rufoque variegato, thorace in medio macula transversa fusco-nigra, elytris creberime nigro-irroratis ; tarsis posterioribus baud elongatis, articulo quarto inferne baud posterius lobato-producto, unguiculo interno quam externo vix duplo lonofiore. Lon^ij. 12, lat. 6i m.m. The male has the basal joints of the front and middle tarsi a little incrassate and very compressed, and fui-nished beneath with four rows of narrow elongate palettes, the marginal hairs are but little developed ; the claws on the front feet are short but unequal, the anterior one is a little the longer, and is swollen at the base and bent at a little distance beyond the swelling so as to give the appearance of an emai-gination close to the base, the hinder one is shorter and its basal thickening extends for about half the length of the claw; the claws of the middle tarsi are longer than those of the front feet, and are rather slender and nearly equal, the inner onft however is rather shorter than the other, and is distinctly bisinuate beneath. The Australian specimens are generally larger and in proportion narrower than those from other localities, and often have the front claw^ on the middle male feet thicker ; these differences however are neither important nor constant. Australia, very abundant ; New Zealand, common ; New Caledonia, common ; South Japan, China, Java, Assam, Himalaya, Mesopotamia, Egypt, Algeria, Southern and Central Europe, but wanting or extremely rare in Northern Europe. 873. 925. Rhantus elevatus, n. sp. — Ovalis, latiusculus, sat convexus, nitidus, subtus niger, prosterno rufescente, antennis pedibusque anterioribus testaceis, posterioribus piceis, supra testaceus, capite posterius nigro, rufo-bimaculato, prothorace in medio transvertim fuscescente, elytris creberrime nigro-irroratis ; tarsis posterioribus brevibus, articulo quarto inferne leviter posterius lobato-producto, unguiculo interno quam externo baud duplo longiore. Long. 11?, lat. 6 m.m. 610 On Aquatic Carnivorous Coleoptera or Dytiscidce. The male has the basal joints of the front and middle tarsi a little incrassate and extremely compressed, and furnished beneath with four rows of nan-ow elongate palettes, the marginal hairs are but little developed ; the claws on the front foot are moderately long and slender, and are nearly equal and simple, the front one being obscurely bisinuate beneath : the claws of the middle feet are nearly as long as those of the front feet, and are simple and equal. Although closely allied to Colymbetes pulverosus, this is an undoubtedly distinct species, it is rather more convex, and has the hind legs thicker and shorter, and the male anterior claws much longer. o Arabia, (El Hedjaz, Dr. MUlingen). 874. 926. Dytiscus signatus, Fab., -R/ja?i9. Colymbetes ruj^ipennis, n. sp. — Ovalis, parum convexus, subtus niger, su^ira capite anterius rufo, posterius nigro rufo-bimaculato, prothorace testaceo, medio plaga nigro-fusca, elytris fuscis lateribus testaceis, pedibus rufis ; prothorace crebrius reticulate, lateribus versus angulos posteriores parum rotundatis ; elytris profunda transversim strigosi.s, strigis secundum sexum profundis. Long. 15|, lat. 7l m.m. The male differs very little in sculpture from Colymbetes sculptilis, but the female departs considerably in sculpture from the male, the reticulations of the thorax being very deep, and the transverse grooves on the elytra being considerably deeper on the basal half, while on the apical half they are hardly so deep or approximate as they are in Colymbetes sculptilis. The male tarsi are strongly dilated and very little compressed. Although closely allied to Colymbetes sculptilis, this appears to me a distinct species, it is smaller and less elongate, and less convex, the male tarsi are broader, less compressed, and the female is easily distinguished by its sculpture. Nortli America. (Nortlieni lioundary of Nebraska, Sepr. IST-i). 91G. 970. Colymbetes thomsoni, n. sp. — Ovalis, parum convexus, subtus niger, supra capite anterius rufo, posterius nigro, rufo-bimaculato, prothorace testaceo, medio plaga nigro-fu.sca, elytris fuscis lateribus testaceis, pedibus rufis ; prothorace hand profunde reticulato, elytris profunde transversim strigosis. Long. 15, lat. *7h m.m. The male has the front tarsi only moderately dilated and quite distinctly com- pressed ; in the female the reticulations of the thoi'ax are deeper than in the male, and the striae on the basal portion of the elytra are deeper and less distant. Lapland, Iceland, (Greenland/). 917. 971. Dytiscus dolabratus, Payk., Cymatoj^terus dolabratus, M.C. — Ovalis, parum convexus, subtus niger, segmentis ventralibus anguste rufo-fasciatis, ultimo dimidio parte rufo, supra capite anterius rufo, posterius nigro, rufo-bimaculato, prothorace testaceo medio plaga nigro-fusca, elytris fuscis lateribus testaceis ; pro- thorace crebrius reticulato, elytris profunde transversim strigosis. Long. Iti, iat. 7f m.m. On Aquatic Ca rnivorons Coleoptera or Dytiscidce. 629 The male has the front and middle tarsi well dilated and considerably compressed. The reticulate sculpture of its thorax is very well marked ; the female has this reticulate sculpture just a little deeper, while the striae on the basal portion of the elytra are much deeper and coarser than in the male, so that they appear more approximate. Northern Eurojie, Siberia, (Sweden, Lapland, Finland to 69° Salilberg). 918. 972. Dytiscus sti'iatus, Lin., Cymatopterus striatus, M.C — Ovalis, elongatus, haud angustus, sat convcxus, subtus niger, supra capite anterius rufo, posterius nigro, rufo-bimaculato, thorace iestaceo, medio plaga nigro-fusca, elytris fuscis, lateribus testaceis, antennis pedibusoue rufis ; prothorace crebrius reticulato ; elytris profunde transversim strigosis, strigis approximatis. Long. 171, lat. 9 m.m. In the male the reticulation of the thorax is quite distinct and regular and covers nearly all the surface, and in the female it is a little deeper ; the transverse strise on the elytra of the male are moderately deep and but little distant from one another ; in the female they are much deeper and coarser, but at the extremity become fine and are on that part the same as in the male. The male has the front and middle tarsi broadly dilated and but little compressed. Northern Europe, (Sweden, Finland, North Geruiauy ; Siberia, sec. Sahllierg). 919. 973. Dytiscus fuscus, Lin., Cymatopterus fuscus, M.C. — Ovalis, sat elongatus et convexus^ subtus niger, supra capite anterius rufo, posterius nigro rufo-bimaculato, prothorace medio late fusco, lateribus testaceis, elytris fuscis lateribus testaceis, antennis pedibusque anterioribus rufis, his femoribns infuscatis, pedibus posterioribus nigricantibus, tarsis dilutioribus ; prothorace crebre subtiliter vermiculato, elytris minus profunde transversim strigosis, strigis approximatis ; abdomine sutura secunda ventrali utrinque prope medium rude serratulo. Long. 16, lat. 8? m.m. The male has the basal joints of the front and middle tarsi moderately dilated and much compressed, and furnished beneath with four series of rather large, quite round, closely packed palettes ; the marginal hairs are comparatively little developed. There is no sexual difference of sculpture. The species varies somewhat in colour and a good deal in length ; the more elongate and darker specimens resemble a good deal, C paykulli, and the re- semblance is increased when, as is occasionally seen, such individuals have the epipleurse infuscate ; but the coarse short plicate elevations of the second ventral suture in D. fuscus allow it to be readily recognized even in its extreme varieties. Europe, Algeria, Sp-ia, (Sweden ; Finland 63", Sahlberg ; Britain, Orkney Islands ; France, Germany Spain, Italy, Corsica, Crete, Smyrna). 920. 4 M2 630 On Aquatic Carnivorous Coleoptcra or DijtiscidcB. 974. Colymbetes substrigatus, n. sp, — Ovalis, eloiigatus, sat convexus, nitldus, nigro-piceus, antennis palpis, capite anterius et in medio verticis thoraceque ad latera rufescentibus, elytris parum conspicue transversim testaceo-undulatis; corpore sublsevigato, elytris obsolete transversim strigosis, versus suturam Isevigatis, })uucti3 seriatis conspicuis, abdomine sutura secunda ventrali utrinque prope medium conspicue serratulo. Long. 16, lat. 81 m.m. The male has the basal joints of the front and middle tarsi slightly incrassate but greatly compressed, and furnished beneath with four series of rather small round palettes ; there is but little sexual difference of sculpture, the transverse striae are rather less distinct in the male than in the female. The species resembles Dytiscus fuscus, but is rather smaller and darker in colour than the average repre- sentatives of that species, and is very readily distinguished by its obsolete sculpture. Arabia. 921. 975. Colymbetes piceus, Klug, M.C. — Ovalis, sat elongatus et convexus, nitidus, nigro-piceus, antennis palpis capite anterius et in medio verticis thoraceque ad latera rufescentibus, elytris parum conspicue transversim rufo-undulatis ; corpore sublsevigato, elytrorum punctis seriatis conspicuis; abdomine subura secunda ventrali utrinque prope medium conspicue serratulo. Long. 155, lat 8 m.m. This species is excessively closely allied to C substrigatus, but is a little smaller and less elongate, and shows scarcely any rudiments of the transverse sculpture of the wing-cases ; it is also a little smaller and less elongate. The male characters seem to be quite the same, the female T have not seen. SinaL 922. Q7&. Colymbetes vagans, n. sp. — Ovalis, latior, convexus, nitidus, piceus, antennis pedibusque rufis, capite anterius et in medio verticis ferrugineo, prothorace elytrisque lateribus basi nifo-testaceis, his versus latera rufescentibus et transversim nigro- irroratis ; corpore subloevigato, supra subtilissime punctulato, elytris punctis seriatis conspicuis, abdomine sutura secunda ventrali utrinque prope medium evidenter serratulo. Long. 1 5, lat. 8 m.m. This species is very closely allied to the preceding, but is distinguished by its broader, shorter form, and its more dilute colour. On the elytra near the sides towards the extremity, there may be detected traces of undulated transverse sculpture, which seems to arise rather from a peculiar arrangement of the very fine punctures, than from the existence of any distinct transverse striae. The hind legs are shorter and stouter than in the allied species. The male characters seem to be nearly the On Aquatic Carnivorous Coleojjtera or DytiscidcB. 631 same as in the two preceding species, the front tarsi are perhaps still narrower. The female I have not seen. Found by Dr. Millingen, in the East; T believe in the western part of Northern Persia. 92.3. 977. Colyrabetes procerus, n. sp. — Ovalis, elongatus, angustuliis, sat convexus, nitidus, nigricans, antennis palpisque rufis, pedibus antei'ioribus rufo-obscuris, posterioribus nigricantibus, capite anterius et in medio verticis rufescente, prothorace lateribus elytrisque testaceis, his creberrime transversim nigro-irroi'atis ; corpore sublaevigato ; elytris punctis seriatis subtilibus sed conspicuis ; abdomine sutura seciinda ventrali utrinque prope medium evidenter serratulo. Long. 15, lat. 7\ m.m. This species is narrower than its allies, and the mixture of ti'ans verse yellow and black marks on the wing-cases is not so indistinct; their sculpture is even more indistinct than it is in C. vagans, and there is a scarcely perceptible difference in the sculpture of the sexes. The male characters are similar to those of the allies. Arabia. 924. I. 64.— Genus MELADEMA. Side pieces of fourth and following ventral segments very narrow ; metasternal groove moderately well developed ; hind tarsi elongate, their terminal joint distinctly longer than the preceding one. Only two species,"'' from Southern Europe, the Canary Islands and Madeira are known to me. 978. Meladema coriacea, Cast., Scutopterus coriaceus, M.C. — Oblongo-ovalis, latiusculus, parum convexus, subopacus, niger, antennis palpisque rufis, pedibus nigro-piceis, vertice parum distincte rufo-binotato ; thorace coriaceo, basi utrinque profundius emarginato ; elytris punctis impressis quasi scutatis densis sculpturatis, punctis seriatis conspicuis. Long. 21, lat. 12 m.m. The male has the three basal joints of the front tarsi considerably dilated, and but little compressed, and furnished beneath with four series of rather large palettes, the marginal hairs are rather well developed, and there is a narrow basal band of pubescence, close to the first series of palettes, the fourth joint is short, and is dis- tinctly incrassate ; the claws are moderately long, and nearly simple and equal : the tarsi of the intermediate pair of legs have the basal joints more compressed, • Scutopterus imbricatus, Well. (No. 1505 huj. op.), Madeira, is a third species of the genus. 632 Oil Aquatic Carnivorous Coleoptera or Dytiscidce. and the fourth joint more elongate than on the front feet. There is no difference in the sculpture of the sexes. The species varies but little, and is readily distinguished by the peculiar sculpture of the wing-cases which aie covered with curved transverse impressions, having very much the appearance of scales. Southei-n Europe, Noitlieni Africa, Canary Islands, (C. Verde Islands'!). (Soiitliem France, Spain, Portugal, Sardinia, Sicily). 925. 979. Dytiscus lanio, Fab., Scutoptevus lanio, M.C. — Oblongo-ovalis, parum con- vexus, nitidus, piceo-niger, prosterno piceo, antennis, palpis, pedibus anterioribus, capite anterius, vertice maculis transversis prothoracisque lateribus rufis, elytris brunneo-testaceis, creberrime nigro-irroratis, prothorace opaco, jirofundius irregu- lariter reticulato ; elytris nitidis, obsolete tuberculatis, punctis seriatis conspicuis. Long. 22, lat. lOl m.m. The male characters are quite the same as in the preceding species, and there is no sexual difference of sculpture : it is probable however that the sculptui'e of the wing cases in the female is variable, for in Aube's type of that sex the elytra bear on their anterior portion curved impressions, approximating to what exists in Meladema coriacea. Scutopterus imbricatus, Woll. Tr. Ent. Soc. 1871, p. 220, (No 1,505 huj. op.) is apparently a closely allied species from the same locality. Madeira. ( 1 North Africa). 926. II. 12. — Group Dytiscini. Abdominal stigma of last two segments enlarged, that on the penultimate seg- ment being at least, 1 m.m. in diameter, or more than one-third of the half- width of the dorsal aspect of the segment. Stigmatic rugse on side piece of first ventral segment highly developed. Swimming legs rather slender, terminated by two nearly equal claws. Outline of eye not emarginate at inner edge. Male anterior tarsi with the three basal joints dilated and coadapted to form a nearly circular plate. Only two genera are comprised in this group ; they may be very readily distin- tfuished as follows : — Elytra with a lateral yellow stripe. DYTISCUS. {Vide p. 634.) Elytra without a lateral yellow stripe. HYDERODES. ( Vide p. 633.) On Aquatic Carnivorous Coleoptera or Dytiscidce. 633 I. 65.— Genus HYDERODES. Yellow colour of clypeus not sharply limited from the dark colour of the front of the head ; and this dark colour in the middle extends distinctly on to the clypeus. Clypeal suture obliterated in the middle. Elytra unicolorous, destitute of yellow border. This genus comprises only three species, peculiar to Australia and Tasmania. 980. riyderodes shuckardi, Hope, M.C — Ovalis, robustus, convexus, nigricans, superne (prgesertim in thorace), nitidus, subviridescens, clypeo et prothoracis lateribus testaceis, antennis rufis, pedibas piceis ; prothorace lateribus crasse margi- nalis, intra marginsm parum impresso ; elytris punctis seriatis conspicuis, punctis- que sparsis minutis versus latera et apicem minus subtilibus. Long. 1 9, lat. 11 m.m. Var. feminae, thorace elj^trisque opacis, rugosis, quasi profunde erosis. The male lias the three basal joints of the front tarsi very broadly dilated, and coadapted to form a circular plate, which is furnished beneath with large and distinctly stalked palettes rather variable in size, the marginal ones being smaller, but the four near the base larger than the rest ; the fourth joint is quite simple and rather short, the fifth rather long, about equal to the length of the three dilated basal joints, the claws are moderately long and a little unequal, the anterior one being more curved than the other. The intermediate tarsi have the three basal joints much dilated, so as to form an oblong oval plate, which is furnished beneath with palettes similar to those of the front feet, but differing less inter se as to size, and leaving a bare glabrous space at the base of the tarsus ; on the hind feet four joints of the tarsus are furnished beneath rather scantily with fine hairs. The female is a little smaller than the male and shows a slight difference in the form of the thorax : the second form of this sex with deeply corroded upper surface is very remarkable. According to the specimens before me the species varies a good deal in breadtli, and somewhat in colour, the greenish-black tinge of the uppersur face giving place sometimes to a piceous tint ; the length and breadth of the prosternal process also exhibit a good deal of variation. Tasmania, South Australia, New Soutli Wales. 932. 981. Hyderodes crassus, n. sp. — Ovalis, latus, robustus, convexus, nigricans, nitidus, superne subviridescens, clypeo et prothoracis lateribus testaceis, antennis rufis, pedibus piceis ; prothorace lateribus baud crasse marginatis, sed intra mar- ginem conspicue depresso ; elytris punctis seriatis conspicuis, punctisque sparsis versus latera et apicem minus subtilibus. Long. 19, lat. II2 m.m. 634 On Aquatic Carnivorous Coleoptera or Dytiscidce. The characters of the male are similar to those of H. shuckardi, except that the circular plate formed by the three dilated joints of the front tarsi is not quite so large and broad, and the four palettes near the base are not so much larger than the others. The species is closely allied to H. shuckardi, but is easily distinguished ; it is a little broader, and (besides the difference in the sides of the thorax of the two species) in the one now under consideration the wing-cases have a slight explana- tion of their lateral margins near the apex, and their outline is not so continuous with that of the thorax, and the scattered punctures are more conspicuous. The corresponding sexes of the two should be compared, in order that the sexual differences in the outline of the thorax should be allowed for. I have not yet seen a rufifose form of the female. d Australia, (King George's Sound, West Australia). 93.3. 982. Hyderodes collaris, n. sp. — Ovalis, robustus, convexus, piceo-niger, clypeo, prothoracis lateribus antennisque rufis, pedibus piceo-rufis ; prothorace lateribus baud discrete et parum crasse marginatis, sed intra marginem conspicue depresso ; elytrorum humeris praminulis ; prosterni processu angusto. Long. 19, lat. 11 m.m. I have seen only a single individual of this species, it is a rugose female ; the prominent shoulders and the very narrow and contracted prosternal process and metasternal groove, will easily lead to the recognition of the other forms of the species when they are discovered. North-west Australia. 934. 1. 66.— Genus Dyr/SCf/S. Clypeus entirely yellow, the yellow colour sharply limited in a straight line from the dark colour of the front of the head. Clypeal suture entire, thoush sometimes so indistinct in the middle as not to be perceived at first glance. Elytra with a yellow lateral stripe. The species* are characteristic of the northern parts of the Old and New Worlds, • The following species' descriptions also refer to this genus : Dytiscus anxius, Mann. (No. 1,285 huj. op.); North America. — Dytiscus confusus, Motsch. (No. 1,287) ?=No. 99.5; Siberia. — Dytiscus front- alis, Motsch. (No. 1,291); Kamtschatka. — Dytiscus fusco-striatus, Motsch. (No. 1,292) j North America. — Dytiscus ibericus, Eos. (No. 1,293); Spain. On Aquatic Carnivorous Coleoptera or Dytiscidce. 635 and do not reach the tropics. They are of large stature, and may be arranged in four groups as follows : — Group 1. — Labvum distinctlj' emarginate in middle; apices of coxal processes not spinose. Nos. 983 to 994. Group 2. — Labrum distinctly emarginate in middle ; apices of coxal processes acutely spinose. Nos. 99.5 to 1,002. Group 3. — Labrum truncate in middle ; apices of coxal processes acutely spinose ; margins of elytra dilated. No. 1,003. Group 4. — Labrum nearly truncate in middle ; apices of coxal processes obtuse ; margins of elytra nearly simple. No. 1,004. Group 1. 983. Dytlscus punctulatus, Fab., M.C. — Nigro-piceus, prothoracis elytrorumque lateribus flavo-marginatis, antennis rufis ; angustulus, elytris posterius crebrius punc- tatis ; pedibus gracilibus, femoribus posterioribus dense subtilissime punctulatis ; prosterni processu acuminate, sat elongato ; coxarum processubus rotundatis ; elytris versus latera ultra medium longitudinaliter impressis. Long. 29, lat. 14 m.m. Mas, nitidus. Fern., subopaca, crebrius punctulata, elytris ad basin ultra medium sulcatis. In the male the small palettes of the front and middle tarsi are excessively small, so as to have a spongy appearance. This species is readily distinguished by the dark undersurface, the slender hind legs, and rounded coxal processes, and the greater than usual punctuation of the elytra. The differences between the two sexes are great and constant. In the female the eighth interstice is always greatly abbreviated and is broken up into granules at its termination. The species seems subject to little variation except in size. Northern and Central Europe, (Sweden, Britain, Northern France, Geneva, Germany). 935. 984. Dytiscus sharpi, Wehncke, Stet, Ent. Zeit. 1875, p. 500. — Latiusculus, supra parum convexus, nigro-piceus, parum nitidus, prothoracis elytrorumque lateri- bus flavo-marginatis, pedibus piceis ; elytris versus apicem minus subtiliter et con- fertim subrugoloso-punctatis ; femoribus posterioribus maris crebre subtiliterque sed conspicuiter punctatis ; coxarum processubus rotundatis. Long. 30, lat. 16 m.m. I have seen but a single male individual of this species, which appears to be a very distinct one. It agrees with Dytiscus punctulatus in colour, and the shape of the coxal processes, but differs from it in form, punctuation, and in the greater size of the small palettes of the front and middle tarsi of the male ; in this later respect it resembles D. dimidiatus. The lateral yellow band of the elytra becomes oblite- TBANS. EOr. DUB. SOC, N.S , VOL. II. 4 N 636 On Aquatic Carnivorous Coleoptera or Dytiscidce. rated before the extremity. The punctuation of the elytra instead of being dense towards the apical portion, as in D. punctulatus, is much more scanty, and is of a peculiar character, being somewhat coarse and yet indistinct, and also somewhat transversely rugulose. •Japan. 981. 985. Dytiscus fasciventris, Say, M.C. — Subtus ferrugineus, nigro-variegatus, supra nigricans, prothoracis elytrorumque lateribus flavo marginatis, antennis pedi- busque rufescentibus, tibiis tarsisque picescentibus ; elytris posterius crebrius punctatis, pedibus posterioribus minus gracilibus, femoribus maris obsolete fem- inee fortiter punctatis ; prosterni processu acuminato, sat elongato ; coxarum pro- cessubus rotundatis. Long. 26, lat. 13 m.m. Mas, nitidus. Fern., parum nitida crebrius punctata, elytris ad basin ultra medium sulcatis. The male has the small palettes of the front feet small but distinct, and larger than those on the middle feet which are quite small. The female has the sides of the thorax a good deal punctured, but the punctuation on the middle is very slight ; the hind coxae in it are also distinctly punctured, and the punctuation of the hind femora and tibioe is much greater than in the male ; the differences between the sexes are very marked and constant. The species is subject to considerable variation in size, and to some in coloration ; occasionally the hind and front margins of the thorax are vaguely yellowish ; the colour of the undersurface is generally reddish, with the middle of the metasternum and sutures of the breast blackish, and the ventral sutures are generally narrowly black, the dark colour being dilated into a blotch on each side, but not extend- ing to the epipleurse ; the dark coluur seems to be sometimes extended and diflused. Though undoubtedly allied to D. punctulatus, the species is readily distinguished by the different colour, by the stouter hind legs, with different punctuation on the femora, by the greater development of the small palettes on the front feet of the male, and the unabbreviated eighth interstice of the female. Eastern Nortli America. United States and Canada. 936. 986. Dytiscus habilis. Say, M.C. — Subtus ferrugineus, nigro-variegatus, supra nigricans, prothorace limbo omni late flavo, elytris margine flavo ad apicem dilatato et fere diviso, antennis pedibusque rufescentibus, tibiis tarsisque posterioi'ibus nigricantibus ; angustulus, transversim aequaliter convexus; pedibus posterioribus robustis, femoribus glabris ; prosterni processu angusto, elongato, apice minute recurvo ; coxarum processubus rotundatis ; elytris versus latera paulo ultra medium longitudinaliter impressis. Long. 26?, lat. ISj m.m. On Aquatic Carnivorous Coleoptera or DytiscidoB. 637 Mas, nitidus, elytvls apicem versus extenie parce subtiliter punctatis. Fern., minus nitida, prothorace versus latera rugoso-punctato, elytris versus basin externe crebrius minute punctulatis, ad apicem fortiter parciusque punctatis. In the male the small palettes of the front tarsi are well developed while those on the middle feet are minute and of a spongy appearance. The sexual differences of sculpture are not striking, and there is apparently only one form of female. This species and Dytiscus hybridus have the outline of the thorax and elytra more completely continuous than in any of the other allies, and the elytra are less sinuate at the apex. In D. habilis the broad yellow margins of the short thorax reduce the middle patch of dark colour to a transverse band ; beneath the thorax is yellow with the prosternal process blackish, the metasternum in the middle and the coxal processes are blackish, the large coxte being ferruginous ; the ventral segments are pitchy ferruginous, with indistinct black fasciee. I have observed very little variation in this species. Mexico. 037. 987. Dytiscus hybridus, Aube, M.C. — Subtus piceus, supra nigricans, prothorace ad latera late, ad marginem anteriorem obsolete, flavo-marginato, elytris margine flavo ad apicem parum dilatato et disintegrate, antennis pedibusque quatuor anterioribus rufis ; angustulus, sequaliter transversim convexus; pedibus posterioribus bi'evibus, robustis ; prosterni processu angusto, sat elongate, apice minute recurve ; coxarum processubus parum divergentibus, rotundatis. ' Long. 27, lat. 1 4 m.m. Mas, nitidus, elytris ad apicem perparum punctatis. Fern., sat nitida, prothorace versus latera plus minusve punctate, elytris versus basin externe minute punctulatis, versus apicem externe sparsim punctatis. The male has the small palettes on the front tarsi largely developed and of equal size ; those on the middle feet are also well developed and are placed so as to leave a narrow, bare, longitudinal space along the middle. The female departs but little from the male, but its sculpture is variable, when most developed the punctures of the thorax are connected (or rugose) and the minute punctures on the base of the elytra are numerous and distinct ; when most diminished, the thoracic punctures are but little connected inter se, and the basal elytral punctures are scarcely to be detected. This species has the superficial appearance of a species of Cybister on account of its short thick hind legs, its continuous outline, and rather broad and distinct yellow lateral band. Except in the sculjiture of the females I have observed extremely little variation. I consider it the most highly developed species of the genus. Eastern North America. (Massachusetts ; Pennsylvania, Kansas, Illinois, sec. Crotch). 938. 4N3 638 On Aquatic Carnivorous Coleoptera or DytiscidcB. 988. Dytiscus verticalis, Say, M.C. — Latus et robustus, parum nitidus, subtus piceus, supra nigricans, prothorace elytrisque flavo-marginatis, antennis piceo-iufis, basi rufo, pedibus piceis femoribus quatuor anterioribus rufis ; dytrorum margine flavo ad finem angusto et ab apice remoto ; pedibus posterioribus robustis ; prosterni processu angustulo sat elongato : coxarum processubus latis, rotundatis ; labro in medio anguste sed profuude emarginato. Long. 32, lat. 17 m.m. Mas, prothorace fere aequaliter transversim convexo, elytris etiam ad apicem fere impunctatis. Fern., prothorace intra marginem lateral em impresso, capite in medio prothoracis- que lateribus crebre punctatis, elytris sparsim subtiliter punctatis. The male has the small palettes on the front tai'si highly developed ; those on the middle tarsi are also well developed, though not quite so large as on the front feet. Except in size the species exhibits very little variation. The large size, and broad form, and the nature of the apical yellow fascia of the elytra give this species some resemblance to D. harrisi (No. 1,004), D. verticalis is however considerably smaller, has the thorax in front and behind without distinct yellow margin, the notch in the middle of the labrum longer, besides numerous other less conspicuous differences. Eastern North America, (Cauada, Lake Superior, New York, Penn.sylvauia). 939. 989. Dytiscus marginicollis, Lee, M.C. — Elongato-ovalis, elytris posterius rotun- datis, parum truncatis, subtus testaceus, parum nigro-variegatus, supra brunneo- olivaceus (?), prothorace limbo omni late flavo-marginato, elytris margine flavo ad apicem lato et minus obsoleto, antennis pedibusque rufis, tibiis tarsisque posteri- oribus obscurioribus ; pedibus posterioribus gracilibus ; prosterni processu elongato ; coxarum processubus obtusis. Long. 29, lat. 14 m.m. Mas, nitidus, elytris ad apicem perparum punctatis. This species is only very imperfectly known to me, the two males before me being in very bad condition. The broad yellow margins on its thorax, and the general form cause it to resemble the Mexican Dytiscus habilis, from which how- ever it is distinguished by its parallel prostei-nal process, and by its more divergent coxal processes, with less rounded apices, and its more slender swimming legs. The front and middle tarsi seem to be extremely similar to those of D. habilis. So far as I can judge, it would seem that the species is about intermediate be- tween D. habilis, and D. sublimbatus. North America, (Califoniia and Kansas, Crotch.). 1140. 990. Dytiscus sublimbatus, Lee, M.C. — Subtus testaceus, metasterno in medio coxarumque processubus picescentibus, supra niger, prothorace limbo omni flavo- On Aqimtic Carnivorous Coleoptera or Dytiscidcs. 639 marginato, sed margine basali angnsto ; elytris margine flavo ad apicem lato sed per-obsoleto, antennis pedibusque rufis, tibiis tarsisque posterioribus obscurioribus ; pedibus posterioribus baud brevibus ; prosterni processu sat lato ; coxarum process- ubiis obtusis. Long. 30, lat. 15 m.tn. .1/as, elytris ad apicem parum puuctatis. Fern. («), elytris ad basin paulo ultra medium sulcatis, apice sat crebre punctatis ; prothorace crebrius punctato. (h), Sat nitida, elytris baud sulcatis, ad apicem parcius punctatis, prothorace ad latera subtiliter punctato. In the male the small palettes on the front feet are moderately developed, while those on the middle feet are quite small. The species is rather more elongate than D. fasciventris, and may be readily distinguished therefrom by the less punctuation of the apical half of the elytra, by the front and hind margins of the thorax being more distinctly bordered with yellow, and by the absence of black markings on the ventral segments, as well as by several other minor characters. It is about intermediate between D. fasciventris and D. margi.ialis. The yellow basal margin of the thorax is moderately broad in front of the scutellum, but towards the sides is excessively narrow. I have seen only two pairs that I can refer to this species, and I feel not quite sure that they may not represent two distinct sj^ecies. North America. 940. 991. Dytiscus dimidiatus, Berg., M.C. — Major; anterius angustatus; nitidus, subtus ferrugineus metasterno in medio picescente, supra niger, prothoracis elytrorumque lateribus flavis. antennis pedibusque rufis, tarsis posterioribus nigris ; prosterni processu sat elongate, acuminate ; coxarum processubus obtusis. Long. 35, lat. 18 m.m. (Long. 31-37 m.m.) Mas, elytris ad apicem sat crebre punctatis. Fein., sat nitida elytris ad basin vix ultra medium sulcatis, apice crebre punctatis, prothorace intra marginem sat impresso, lateribus subtiliter punctatis. In the male the small palettes of the front tarsi are rather highly developed, while those on the middle feet are quite small. This species is not closely allied to any other, but is about intermediate between D. punctulatus and D. marginalis. There is a very narrow reddish band on the front of the thorax, and sometimes a yellowish appearance in the front of the scutellum, at the extremity of the wing-cases the yellow band is divided by a very large patch of dark colour, and the anterior portion of the band is placed at a con- siderable distance in front of the apex. The female is always sulcate, and the interstices of the grooves are but little punctured. The species exhibits little variation ; there is however a tendency in the females to a breaking up of the 'UO On Aquatic Carnivorous Coleoptera or Di/tiscidce. interstices between the grooves by impressions or divisions, and I have one individual in which this is carried to such an extent that the tenth interstice is represented only by some detached granules, and the ninth is also greatly divided. Europe ; Asia Minor, sec. Bedel. (Sweden ; Finland, 60° 50' Sahlberg ; England ; France ; Germany. 941. 992. Dytiscus pisauus, Lap., M.C — Subtus testaceus, metasteruo in medio suturisque plus minusve nigricantibus, supra nigro-olivaceus, prothorace limbo omni elytrorumque lateribus flavo-marginatis, antennis pedibusque testaceis, tarsis posterioribus piceis : prosterui processu sat elongate et acuminate ; coxarum processubus rotundato-obtusis. Long. 30, lat 1 5 m.m. Mas, nitidus, elytris versus apicem sat crebre punctatis. Fern., subopaca, elytris ad basin paulo ultra medium sulcatis, ad apicem crebre punctatis; prothorace uudique crebre punctato. The male has the small palettes on the front feet highly developed, while those on the middle tarsi are much smaller. The species is closely allied to D. margin alls, and has exactly the same appear- ance, but it is undoubtedly distinct ; the prosternal process is longer and narrower, the coxal processes are more obtuse, and the furrows on the elytra of the female are rather shorter. The individuals of this species are nearly always somewhat smaller than D. marginalis. The extent of the black marks on the undersurface is subject to a good deal of variation : only sulcate females occur, smooth ones being quite unknown. Southeni Europe, Corsica, Sardinia, Algeria ; (Southern France, Spain. Italy). 942. 993. Dytiscus persicus, Wehncke, Stet. Ent. Zeit. 1S76, p. 52. — Augustulus, subtus testaceus, nigro-variegatus ; supra capite thoraceque nigricantibus, hoc limbo omni late flavo-marginato, elytris castaneis, late flavo-marginatis ; prosterni processu sat lato ; coxarum processubus brevibus, obtusis. Long. 29, lat. 14 m.m. Mas, latet. Fem , nitida, prothorace subtiliter punctulata, intra inarginem impresso ; elytris ad apicem crebre punctatis. This species seems to be most allied to D. pisanus, but is narrower and more parallel, and is peculiar in the colour of the wing-cases, which seem also to be of softer texture than usual : as yet the species is known only by smooth females, so that in this respect it differs totally from D. pisanus ; compared with the female of D. pisanus, the punctuation of the thorax is much less, and that on the apical portion of the elytra is less regular and scarcely extends so far forwards : the coxal processes are quite as short as in D. pisanus, and their apices, just a little less On Aquatic Carnivorous Coleoptera or Dytiscidce. 641 rounded ; the prosternal process is slightly shorter and broader. It would thus appear that this female in structure a good deal resembles D. pisanus, with an approximation towards D. marginalis, and with the punctuation almost similar to (the smooth female of) that species. Persia; found (I believe at Ispakiu) bv the Marquis Jacques Doria in 1862 or '63. 943. 994. Dytiscus marginahs, Linn., M.C — Subtus testaceus, metasterno in medio nigricante, supra nigro-olivaceus, prothorace limbo omni elytrisque lateribus flavo- marginatis, antennis pedibusque rufis, tarsis posterioribus plus minusve picescenti- bu>; prosterni processu lato, hand elongato, coxarum processubus brevibus, sat acuminatis. Long. 33, lat. 18 m.m. (Long. 26-34 m.m.) ^fas, nitidus, elytris ad apicem sat punctatis. Fern, [a), subopaca, elytris ad basin ultra medium sulcatis, ad apicem crebrius et fortius punctatis, prothorace undique crebrius parum subtiliter punctato. (b), nitida, prothorace subopaco, undique subtiliter punctulato, elytris apicem versus crebrius quam in mare punctatis. The male has the siBall palettes on the front feet large and highly developed, those near the two large cups being especially large and distinct, those on the middle feet are very small, but still are to be distinctly distinguished. The species varies a good deal in size, the females being particularly liable to reduction in this respect, and it also varies in the colour of the undersurface, the ventral segments being occasionally much marked with black. Except for these points and the sexual discrepancies, the species shows but little variation ; the individual from Japan is, however, a very broad one, and appears to me to have the small cups of the front male tarsi rather less developed than in the European specmiens. This species is comparatively widely distributed in Europe, it occurs within the Arctic circle, (68°, Sahlberg), and as far south as Geneva, Lombardy, and Trente, and Hautes Pyrenees. It has not been recognized as occurring in America, but I have a female individual labelled, "Am. bor.int., montagnes rocheuses," by Castlenau; and found an individual said to be from North America, in Murray's collection. Europe, Siberia, Japau, North America. 944. Group 2. 995. Dytiscus circumcinctus, Ahr., M.C.— Subtus testaceus vel ferrugineus, metasterno in medio obscuro, supra nigricans, prothorace limbo omni elytrisque flavo-marginatis, antennis pedibusque rufis, tarsis posterioribus picescentibus; pro- sterni processu lato, baud elongato; coxarum processubus apicibus breviter prolon- gatis, angustatis et acuminatis. Long. 32, lat. 16 m.m. Mas, nitidus, elytris ad apicem pavum punctatis. 642 On Aquatic Carnivoroxis Culeoptera or DytiscidcB. Fern, (a), subopaca, elytris ad basin ultra medium sulcatis, ad apicem crebrius punctatis, prothorace undique crebre sed subtiliter punctate. (6), nitida, prothorace vix punctulato, elytris baud sulcatis, ad apicem sat punctatis. The male has the small palettes moderately developed, those on the hinder and inner portion however, a good deal longer than the rest ; the palettes on the middle tarsi are quite small. The species is excessively similar to D. marginalis, but seems perfectly distinct, the apices of the coxal processes are more prolonged, slender, and acute ; the small palettes on the male front feet are less highly developed, and the punctuation on the thorax of the females is finer. The species seems to vary very little ; the North American individuals show no distinction from the European. The yellow mark on the middle of the head is usually smaller than in D. marginalis, while the eyes in all the individuals I have seen have a yellow margin round them. Central Europe, piincipally the North Eastern parts, (Siberia ?); North America. (Sweden ; Finland, 61" 50' Sahlberg ; England ; France ; Germany ; Red River). 945. 996. Dytiscus parvulus, Man., M.C. — Minor, angustulus, subtus testaceus, suturis anguste nigro-cinctis, supra olivaceo-niger, nitidus, prothorace limbo omni elytris - que flavo-marginatis, antennis pedibusque testaceis ; prosterni processu lato, brevi ; coxarum processubus spinoso-acuminatis, sed parum elongatis ; sutura frontali in medio obsoleta. Long. 261, lat. 13 m.m. Mas, nitidus, elytris ad apicem sat punctatis. Fern., nitida, prothorace versus latera verticeque capitis subopacis, elytris baud sulcatis, ut in mare punctatis et nitidis ; prothorace verticeque sparsim subtilissime punctatis, illo intra latera distincte subimpresso. The male tarsi are similar to those of D. dauricus (No. 998) The frontal sutu'e in the male is fine, but .still may be distinguished even in the middle, in the female it is more obsolete than in the male. Although the species has some points of i-esemblance with D. dauricus, it seems to be a very distinct one ; it is smaller and narrower, the female sculjjture is greatly reduced, and the coxal processes, though quite slender, are less elongate, and com- paratively more distant ; the obsolete h'ontal suture of the female is a very i-emark- able distinctive character for that sex. I have seen only one pair of this species ; I believe the two specimens to be really one species, though the sexual difference in the frontal suture appears to be the reverse of what exists in other species. It is doubtful whether Motschulsky's Dytiscus parvulus is this species or D. dauricus, or D. vexatus, but his name may be altogether neglected, his note being an insufficient description. North-western North America ; (Kadjalc, Coll. Brussels Mus. and Mnizech). 1139. On Aquatic Candvorous Coleoptera or Dytisadce. 643 997. Dytiscus vexatns, n. sp. — Subtus testaceus, metasteriio late nigricaute, seg- mentis ventralilius parum nigro-marginatis, supra piceus, prothorace limbo ornni elytrisque flavo-margiiiatis, an tenuis pedibusque rufis, prosterni processu lato, brevi : coxarum processubus apicibus breviter prolongatis, angustatis at acuminatis ; sutura frontali profunda. Long. 29, lat. 15 m.m. The clothing of the male tarsi is similar to that of D. circumcinctus. I have seen only a single male ; it is allied to D. circumcinctus, but is smaller than the smallest male I have seen of that species, it is of a more pitchy colour above, the punctuation at the very apex of the wing-cases is greater, the eyes are not bordered with yellow, and the coxal processes though exceedingly similar iu form are just a trme less elongate, and the frontal suture is deeper ; the undersurface is also rather more marked with black. From D. dauricus, the species differs by the shorter coxal processes, smaller size, and some less important details. North- Western North America. 9i6. 998. Dytiscus dauricus, Gebl., M.C. — Subtus testaceus, conspicue iiigro-variegatus, supra niger, prothorace limbo umni elytrisque flavo-marginatis, antennis pedibus- ([Vlq rufis ; prosterni processu lato^ baud elongato ; coxarum processubus evidenter prolongatis, angustatis et acuminatis: sutura frontali (preesertim in femina) profunda. Long 32, lat. 16 m.m. Mas, nitidus, elytris ad apicem sat punctatis. Fern, (a), subopaca, elytris ad basin ultra medium sulcatis, ad apicem ci'ebrius fortiterque punctatis ; protiiorace undique crebrius fere dense punctate. (6), iiitida, prothorace subopaco, subtiliter crebre punctato, elytris ad apicem sat crebre et fortiter punctatis. The palettes of the male tarsi are formed as in D. circumcinctus. The species is intermediate in most respects between D. circumcinctus, and circurnflexus ; it differs from the former by the greater prolongation of the apices of the coxal processes, by the underside being greatly marked with black, and by the greater thoracic punctuation of the females, while from D. circumfiexus it differs by its rather broader form, less elongate apices of the coxal processes, and shorter prosternal process. The yellow angular mark on the middle of the head generally extends quite forward to join the yellow clypeus. The species seems to vary but little, the Siberian individuals being almost if not quite undistinguishable from the American ones. The species is usually known in collections as D. con- fluens. Say. D. difiinis, Lee, is referred to it as a synonym on the authority of Crotch. Western North America, and Eastern Siberia. (Kansas, Lake Superior, California, Sitkha ; Lake Baikal ; Transbaikal ; Angai'a River). 947. TRANS. BOV. DUB. SOC, N.S., VOL. II. * O 64 4 On Aquatic Carnivorous Coleoptera or iJytiscidai. 999. Dytiscus latro, n. sp. — Elongatus ; subtus testaceus, nigro-variegatus, supia niger, prothorace limbo omni elytrisque flavo-margiaatis, actennis pedibusque rufis ; prosterni processu sat elongate ; coxarum processubus prolongatis, angustatis et acutuinatis. Long. 31, lat. 16 m.m. This s[)ecies is imperfectly known to me by a single individual, which is an unsulcate female ; it is however undoubtedly distinct ; it has the comparatively elongate and slender form of D. circumflexus, and its coxal processes are inter- mediate between those of D. dauricus and D. circumflexus, being shorter than in the latter, longer than in D. dauricus ; the female is however readily distinguished from the unsulcate females of both of the species alluded to by the great develop- ment of the punctuation on the wing-cases ; this punctuation is rather regular as in D. circumflexus, but is much coarser and has a much greater extension towards the base of the elytra. Mantchnria. 948. 1000. Dytiscus piceatus, n. sp. — Elongatus ; subtus testaceus, metasterno in medio nigricante, supra capite thoraceque nigris, hoc tlavo-marginato, elytris rufes- centibus, flavo-marginatis ; prosterni processu sat elongato ; coxarum processubu.s prolongatis, abrupte angustatis, acuminati-s. Long. 33, lat. IG m.m. This species is known to me only by a single male individual ; it is extremelv similar in form to D. circumflexus, and has the small palettes of the dilated tarsi just as in that species ; the colour of the elytra is however reddish, the undersurface is but little marked with black, and the coxal processes are different in form, being rather less elongate than in D. circumflexus, but they are more abruptly narrowed, so that their slender portion is more clearly marked off, somewhat as in O. lapponicus. The punctuation of the apex of the elytra is but slight, even less in fact than in D. circumflexus. Eastern Siberia ; (Ii-kutsk). 949. 1001. Dytiscus circumflexus, Fab., M.C — Elongatus; subtus testaceus, nigro- fasciatus, supra olivaceus, vel viridi-olivaceus, scutello flavescente, prothoi'ace limbo omni elytrisque flavo-marginatis ; antennis pedibusque rufis, tarsis posteriori bus plus minusve picescentibus ; prosterni processu sat elongato ; coxarum processubus valde elongatis, attenuatis, et acuminatis. Long. 33, lat. 16? m.m. Long. 27i 35 m.m. Alas, nitidus, elytris ad apicem parum punctatis. Fern, (o), subopaca, elytris ad basin ultra medium sulcatis, ad apicem crebrius sequaliter punctatis, prothorace undique crebre subtiliter punctato. Fern, (h), nitida, elytris ad apicem sat punctatis, prothorace in medio subtilissime punctato, ad latera subopaco et paulo fortius punctato. On Aquatic Carnivorous Coleoptera or Dytiscidce. 645 The palettes of the male tarsi are moderately developed, and show no difference from what exists in D. circumcinctus. The species is nearly always of more slender form and of a greener colour than the other allies of I )ytiscus margin- alis, and is readily identified by the great elongation of the coxal processes. It varies a good deal in colour, size and width ; the specimens from the northern part of its area of distribution being generally broader and of a less green colour than most of the individuals which are found in southern Spain and Algeria ; in the sulcate female of the larger variety the grooves are generally continued rather nearer to the extremity of the wing-cases. In the north it would seem that sulcate females are more abundant than sniooih ones, while in the south the reverse is the case. Central and Southern Europe ; apparently most common in the neighbourhood of the Mediterranean Sea Corsica, Algeria ; (England, France, Germany, Spain, Corfu, Hungaiy). 950. 1002. Dytiscus lapponicus, Gyll., M.C — Subtus testaceus, abdominis lateribus nigro-maculatis, supra piceus, prothorace limbo omni late flavo-marginato, scutello ffavescente, elytris lateribus lineisque tenuibus flavis ; antennis pedibusque testaceis ; prosterni j^rocessu brevi ; coxarum processubus apicibus distantibus, subito angus- tatis, elongatis et acumiuatis. Long. 27, lat. 13^ m.m. Mas, nitidus, elytris ad apicem fortiter punctatis. Fern, (a), opaca, elytris ad basin ultra medium sulcatis, ad apicem fortiter crebrius punctatis ; prothorace undique creberrime punctato. (6), nitida, prothorace subopaca, prsesertim in medio crebrius subtiliusque punctato, elytris ad apicem fortiter punctatis. The male has the small palettes of the tarsi moderately developed. The species has the outline of the thorax and elytra more discontinuous than in any other species, the tliorax being narrower than usual especially at the base ; the eyes are always largely bordered with yellow : the contraction of the coxal processes takes place on their inner edge just below the coxal notch : the anterior border of the hind coxa approaches nearer to the middle coxa than in any other species, and the terminal portion of the epipleurse is a little broader than in the other species of the D. marginalis group. Thes3 characters allov^• the species to be easily recognized, although it is a very variable one in size and colour. The yellow irregular lines on the elytra can sometimes scarcely be detected ; at other times the yellow colour is more than usually predominant, and the black mark on the middle of the thorax may even be broken up : very rarely the elytra are of a greenish oHvaceus o;.- rather of a piceous colour. The specimens from Northern Germany are larger and darker than any others I have seen. I am not quite certain that the individual, the only one I have seen, from Siberia 4 0.' 646 On Aqiuitic Carnivorous Coleoptera or Dytiscidrp. really belongs to this species ; it is very narro^v, and has the coxal processes shorter and the epipleura3 narrower than any other specimen I have seen. Northern Em-ope aud Siberia : extending southwards in the mountains to the Basses Alpes, aud Korthem Italy, but othenvise not found more to the South than Northern Germany and Central Russia. (Lapland, Scotland, Ireland, Stettin, Berlin. Kasan : Barcelonette ; Lago della Madtlalena.) 951. Group 3. 1003. Dytiscus latissimus, Liun., M.C. — Subtus ferrugineus, supra niger, protho- race liiubo oiuni elytrisque flavo-marginatis, antennis pedibusque rufis, tarsis posterioribus plus minusve picesceutibus ; epipleuris dilatatis ; prosterni processu lato et brevi ; coxarum processubus apicibus distantibus, acuminatis, parum prolongatis : labro medio vix emarginato. Long. 40, lat. 25 m.m. Mas, sat nitidus, elytris apicem versus tantum subtilius punctulatis. Fern., subopaca, prothorace medio utrinque subtilissime punctulatu, elytris louge ultra medium sulcatis, iuterstitiis dense subtilissime punctatis, apice crebre sub- tiliter punctatis, punctisque majoribus parum numerosis. In the male of this species the small palettes of the front tarsi remain unde- veloped, being no larger than those of the intermediate feet. The species is re- markable by the dilated epipleurse with a sharp external edge, and by the fine punctuation of the sulcate female ; the yellow band at the apex is divided into two narrow widely separated portions, the anterioi of which is unusually distinct. The species varies but little, but sometimes there is a more or less extensive appearance of yellow colour on the middle of the wing-cases in the female : notwith- standing the large size of the species, the hind femora are remarkably slendei'. The species is extremely liable to abnormal developments of different parts of the skeleton. An individual possibly a hybrid between this and D. marginalis, or D. dimidiatus has been described by Kraatz, Berl. Ent. Zeit. XVIII, p. 293, pi. I, f. 2, but as the description and figure quite agree with D. harrisii, I am inclined to believe that the supposed hybrid may prove to be an individual of that species. Northern Europe ; (and N. America 1). (Sweden ; Finland to 63°, sec. Sahlberg; Germany : Vosges). 952. Group 4. 1004. Dytiscus harrisi, Kirb , M.C. — Latus, robustus ; subtus testaceo nigroque variegatus, supra niger, prothorace limbo omni elytrisque flavo-marginatis, antennis piceo rufis, femoribus testaceis, tibiis et tarsis pedorum quatuor posteriorum nigri- cantibus ; prosterni procesu brevi et lato ; coxarum processubus brevibus, rotundatis ; labro baud emarginato. Long. 40, lat. 22 m.m. On Aquatic Carnivorous Coleoptei-a or Di/tiscidce. 647 3I(ts, tiitidus, elytris versus apicem crebrius subtiliusque punctatis. Fern., subopaca, prothorace utrinque versus latera subtilissime punctato, elytris ad apicem crebrius subtiliter punctatis, punctis sublateralibus majoribus conspicuis. In the male of this sjDecies the small palettes of the front tarsi remain quite rudimentary and undeveloped, being no larger than those of the intermediate feet. The colour of the under surface in this species is peculiar ; the prosternum is testaceous with its process black, the breast is black with a large dash of yellow on the front part of the hind coxa?, while the ventral segments are yellowish, marked with black especially at the sides and apex : the yellow lateral band of the elytra is broad, and is divided at the apex by a large space into two parts, the anterior of which is quite distinct. I have not seen enough specimens to know whether there is much variation in the species. The species has undoubtedly much in common with D. latissimus, particularly the labrum, the nature of the punctuation, the form of the yellow band at the apex of the elytra, and the condition of the clothing of the male tarsi ; it departs, however, widely therefrom by the undilated margins of the wing-cases, the form of the coxal processes, and the unsulcate elytra in the female. In certain respects it resembles D. verticalis, and although the two at present are widely separated I should not be surprised if intermediate species are found to exist in North America. Noi-th Amei-iea, (Pennsylvania, Kansas, Lake Superior, Vancouver's Land, sec. Crotch). 9.53. III. 4.— Tribe HYDATICIDES. Posterior tarsi with the hind margins of their joints densely fringed with adpressed and flattened cilire or squamsB overlapping the basal portion of the following joint. 7i^ T? F^ T 1*^ ^ Prothorax, with a tine lateral margin, ....... ,„. ° ' (Vide IX 699.) Prothorax without lateral margin, episternal suture curvilinear, spurs of ) Thermonectini. hind tarsi emargiuate at apex. j {Vide p. G7 '2.) Prothorax without lateral margin, episternal suture rectilinear, spurs of] Hydaticini. hind tai-si accuminate at apex. j ( Vide below.) II. 13. — Group Hydaticini. Metathoracic episternum large, the suture between it and the wing of the metasternum rectilinear, spurs of posterior tibia? quite acuminate. Claws of posterior feet nearly equal, i ^fj9-^^'^i^F^'- '■ I (Vide p. 648.) Claws ofposterior feet very unequal | ^rl^/'^^aR^s ^ ( {Vide p. 648.) 648 On Aquatic Carnivorous Coleoptera or Dytiscida. I. 67.— Genus PRODATICUS. Coxal lobes broad, their supra ai-ticular border rather narrow ; claws of hind feet nearly equal in length. The only species is found in western Asia. (Persia and North India). 1005. Prodaticus pictus, n. sp. — Sat latus, parum convexus, nitidus, niger, capite anterius prothoraceque lateribus testaceis, vertice testaceo-bimaculato, elytris maculis decern censpicuis flavis, antennis (parum elongatis) pedibusque anterioribus rufis, pedibus posterioribus piceis : prothorace lateribus subrotundatis, angulis posterioribus obtusis ; tarsorum posticorum unguiculis fere sequalibus ; elytrorum punctis seriatis censpicuis. Long. 15, lat. 8| m.m. The male has the undersurface of the front tarsi irregularly covered with palettes about thirty-six in number, there is no definite division of them into larger and smaller, but those in the middle of the heel are much larger than the marginal ones : the three basal joints of the intermediate tarsi are broad, and bear beneath very numerous small palettes quite irregularly placed, but with a rather broad uncovered line along the middle. The terminal two joints both on the front and middle feet are less elongate and slender than in the allied forms. The yellow marks on the elytra are very conspicuous ; they consist on each of an elongate mark on the shoulder, a very large basal spot near the scutellum, two large spots beyond the middle placed transversely, the inner one rather remote from the suture, and the outer quite separate from the hind margin, and a subapical spot, touching neither the suture nor the outer margin. I have seen only two individuals of this remarkable species, which cannot easily be confounded with any other ; the form of its thorax suggests a likeness to Agabus. Northern India. 1000. I. 68.— Genus HYDAIICUS. Coxal lobes but little developed in the transverse direction, but with broad and definite supra-articular border ; inner claw of hind tarsus tmce as long as the outer. The species are very difficult to distinguish, I arrange them provisionally in three groups viz : — On Aquatic Carnivorous Coleovtera or Dytiscidoe. 649 Group 1. — Serial punctures on the upper face of the hind tibia distant from one another, and quite parallel with the outer border of the tibia ; series of punctures on the upper face of the hind femur consisting of isolated non-pubescent punctures ; front of head not quite so short as, and eyes rather smaller than, in the otlier groups ; Nos. 1006 to 1014. Group 2. — Serial punctures on the upper face of the hind tibia more or less approximate to one another, and not perfectly parallel with the outer margin, the antei-ior being placed rather further from the outer border than the terminal ones are ; series of punctures on the upper face of the hind femur, dense and crowded together, forming a finely pubescent band ; pattern of upper surface variable, but never consist- ing of one or two quite definite longitudinal pale vittae ; middle tarsi of male a good deal dilated; Nos. 1015 to 1043. Group 3. — Pattern of upper surface of wing cases consisting of one or two quite reofular loncjitudinal vittse ; middle tarsi of male but little incrassate ; Nos. 1044 to 1051. The groups cannot be considered either natural or distinct; thus No. 1015 is quite intermediate between the first and second groups, and No. 1044 will probably prove an equally perfect connection between the second and third. Besides the species enumerated in the text, the following descriptions probably refer to species of this genus: — Hydaticus apicalis, Boh. (No. 1,305 huj. op.) near No. 1,041; CafTraria. — Hydaticus aruspex, Clk. (No. 1,306) ; China.— Hydaticus caffer, Boh. (No. 1,308) near No. 1,042 ; Caffraria.— Hydaticus discoidalis, Hope (No. 1,310)? No. 1,029 var. ; Africa. — Hydaticus fulvo-notatus, Clk. (No. 1,311); Africa. — Hydaticus histrio, Clk. (No. 1,312); India. — Hydaticus lateralis, Cast. (No. 1,313); South America. — Hydaticus madagascariensis, Aub6 (No. 1,314) ; Madagascar. — Hydaticus nauzieli, Fairm. (No. 1,315) ?=No. 1,032; France. — Hydaticus nigro-marraoratus, Clk. (No. 1,31G); Angola. Hydaticus nigro-\'ittatus. Clk. (No. 1,317) ?=No. 1,028; Japan. — Hydaticus paganus, Clk. (No. 1,318); Africa. — Hydaticus phUippensis, Wehncke, (No. 1,319); Philippine Islands. — Hydaticus usheri, Clk. (No. 1,321); Africa. — Hydaticus verecundus, Clk. (No. 1,322)? South America. — Hydaticus xanthomelas, BruUe (No. 1,323) ; South America. The systematic position of the following is more doubtful, but may be in Hydaticus: Colymbetes trivittatus, Mont. (No. 1,255) ; Woodlark Islands. — Dytiscus flavo-cinctus, Guer. (No. 1,290); Papua.— Dytiscus unifasciatus. Fab. (No. 1,296) ; Africa. 650 On Aquatic Carnivorous Coleoptera or Dytiscidce. Group 1. 1006. Dytiscus seminiger, deGeer, Hydaticus seininiger, M.C. — Ovalis, sat latus, parum nitidiip, niger, subtus ^^'osterno anterius capiteque in medio testaceis, supra capite thoraceque rutis, illo in vertice nigro rufo-bimaculato, hoc basi in medio extensius nigricante, elytris margine laterali flavo ; antennis pedibusque anterioribus rufis, tibiis intermediis piceis, pedibus posterioribus nigro-piceis, unguiculo interno quam externo vix duplo longiore. Long. 13, lat. 71 m.m. In the male of the sj^^^cies, the fringing hairs of the front tarsi are rather short, and the palettes differ little inter se in size, those at the base not being very large, the claws ai'e rather stout, are abruptly curved at the base and are sinuate beneath ; the middle tarsi are broadly dilated and the basal patch of dense rough seta? is rather large. The female has some coarse impressions on the thorax near the sides, and a few similar marks at the side of each wing-case near the front. The species seems to vary but little, the female often has the black colour on the thorax more extensive than in the male, so that it occasionally nearly attains the front margin, the yellow lateral stripe of the elytra is, too, generally more dis- tinct in its terminal portion than it is in the male. Eui'ope. (Sweden ; Fiulancl, 61°, Sahlberg ; England ; France ; Germany : Alpes IMaiitimes, sec. Bedel). 1038. 1007. Hydaticus modestus, n. sp. — Oblongo-ovalis, parum latus, subtus nigro- piceus, capite prosternoque rufis, supra capite thoraceque rufis, illo in vertice nigro rufo-bimaculato, hoc basi in medio nigro, elytris nigris margine laterali pvinctisque transversis subbasalibus ilavis, antennis pedibusque quatuor anterioribus rufis, pedibus posterioribus piceis, unguiculo interno quam externo hand duplo longiore. Long. 14, lat. 7i m.m. The male has the front tarsi rather large, their claws are ratlier long, are sud- denly bent at the base and are sinuate beneath ; the middle tarsi are broadly dilated, and the basal patch of dense rough setse is very large and conspicuous. I have seen only a single individual of the species (a male in very bad condition) ; it seems to be very closely allied to Dytiscus seminiger, and is extremely similar to it, but is of narrower form, the black colour at the base of the thorax is definitely limited and does not reach quite so far forward as the middle, and there are faint indications of a transverse line of pale colour on the elytra near the base. The apices of the elytra are slightly sinuate, and in the female sex this is no doubt more conspicuous. In size and form it appears to be very similar to Hydaticus america- nus (No. 1009), but seems to Le readily distinguished by the absence of yellow longitudinal lines on the wing-cases. North America. 1037. On Aquatic Carnivorous Coleoptcra or Dijtiscidw. 651 1008. Hydaticus cinctipennis, Aube, M.C. — Ovalis, eloiigatus, subtus nigro- piceus, capite prostenioque rufescentibus, supra capite thoracequc rafis, hoc basi in medio indiscrete infuscato, elytris piceis, vitta hunierali longitudinali elongata, paulo obliqua antice margiuem attingente lateribusque |)arum discrete rufescentibus, antennis pedibusque anterioribus rufis ; pedibus posterioribus picescentibus, ungui- culo interno quam externo duplo longiore. Long. 131, lat. 71 m.m. 1 have seen only a single individual of this species, it is a male in very mutilated condition, the middle tarsi are broadly dilated, but their basal patch of dense rough pubescence is rather small though quite distinct. Though rather similar to H. modestus, the species is readily distinguished from it by the less variegate colour of the upper surface. North America. 103G. 1009. Hydaticus americatius, n. sp. — Oblongo-ovalis, parum latus, subtus nigro- piceus, prosterno capiteque in medio testaceis, supra capite thoraceque rufo-testaceis, illo in vertice nigro rufo-bimaculato, hoc basi in medio nigro, elytris vittis longi- tudinalibus nigris, a vittis flavis fere integris divisis, margine laterali fasciaque lata transversa basali flavis, antennis pedibusque quatuor anterioribus rufis, tibiis intermediis rufo-piceis ; pedibus posterioribus piceis, unguiculo interno quam externo duplo longiore. Long. VSh, lat. 7t m.m. The female of this species has the elytral apices distinctly produced, and sinuate, but it is without any sexual sculpture on the thorax or elytra. The male is unknown to me. This species is very closely allied to Dytiscus stagnalis (No. 1011), and is about as long, but is narrower and of more parallel form, and the yellow lines and fascia of the elytra are a little more distinct and definite, the female has the apices of the elytra produced and no sexual sculpture. North America, (Red River). 1035. 10 !0. Hydaticus hevipennis, Thoms., Op. Knt. Ill, p. 324. — Ovalis, parum latus, subtus nigro-piceus, prosterno capiteque in medio testacei,s, supra capite thoraceque rufo-testaceis, illo m vertice nigro rufo-bimaculato, hoc basi in medio niarro, elytris nigris tsiscia sub-basali transversa parum discreta, margine laterali lineisque tenuibus lougitudinalibus obsoletis, testaceis ; antennis jjedibusque quatuor anteri- oribus rufis, tibiis intermediis rufo-piceis ; pedibus posterioribus piceis, unguiculo interno quam externo baud duplo longiore. Long. 12^, lat 7 m.m. The female of this sj^ecies has the apices of the elytra at the suture a little produced so as to give rise to a conspicuous sub-apical sinuation ; it has impressions on the thorax and elytra as in the corresponding sex of Dytiscus stagnalis. The male is unknown to me. TRANS. KOV. DUU. SOC, X.S., VOL. II. 4 P 652 On Aquatic Carnivorous Coleoptera or DytiscidcB. The species is smaller in size than D. stagnalis, and has the yellow marks of the elytra much less developed, and the elytrtil apices sinuate in the female : this seems to be all there is to distinguish the two forms, which are perhaps not distinct species. The specimen from the Ked River differs from the Finland individual in that it has apparently the claws of the hind tarsi less elongate. Northern Europe; North America; (Sweden: Finland 60° 30', Sahlberg; Red River). 1034. 1011. Dytiscus stagnalis, Fab., Ilydaticus stagiudis, M.C. — Ovalis, latus, ro- bustus, subtus uigro-piceus, prosterno capiteque in medio testaceis, supra capite thoraceque rufo-te^taceis, illo in vertice nigro rufo-bimaculato, hoc basi in medio nigro, elytris vittis longitudinalibus nigris a vittis angustulis flavis divisis, margine lateral! fasciaque transversa basali sat discreta, flavis, antennis pedibusque quatuor anterioribus rufis, tibiis intermediis rufo-piceis ; pedibus posterioribus piceis, ungui- culo interno quam externo vix duplo longiore. Long. 14, lat. 72 m.m. The male has the front tai'si rather large (but their fringing hairs are scarcely so long as in D. transversalis), and their rather elongate claws are abruptly bent near the base, and are sinuate beneath ; the middle legs are thick, their tai'si broadly dilated, and the patch of dense rough setae at the base is large and conspicuous. The female has some impressions on the lateral parts of the thorax, these seem to be never very extensive, but on the lateral and basal parts of the wing-case there is a large development of this sculpture, which however in certain individuals is greatly reduced, The apex of the wing-cases is rounded in both sexes, but in the female the sutural angle is just visibly produced so as to cause an extremely slight apical sinuation. North Europe, Siberia. 1033. 1012. Dytiscus transversalis, Bergst., Ilydaticus transversalis, il/.C— Ovalis, sat latus, parum elongatus, subtus piceus, prosterno capiteque in medio testaceis, supra niger, capite anterius rufo-testaceo et ante verticem rufo-bimaculato, prothorace anterius et ad latera late rufo-testaceo, elytris margine laterali late fasciaque sub- basali transversa testaceis, antennis pedibusque quatuor anterioribus testaceis ; pedibus posterioribus piceis, unguiculo interiore quam exteriore duplo longiore. Lonor. 13 lat. 7 mm. In the male the front tarsi are only moderately large, but their fringing hairs are rather long, their claws are rather small and are simple and gently arcuate ; the middle tarsi are rather broadly dilated, and beneath their patch of dense rough setje at the base (somewhat on the inner side) is distinct but not conspicuous : the female has coarse impressions on the sides of the thorax, which are variable in their extent. In each sex the elytra are simply rounded at the apex. On Aquatic Carnivorous Coleopiera or Dytiscidce. 653 This species seems to vary but little ; the whole of the sutural area of the elytra is broadly and uninterruptedly black, the lateral margin is broadly yellow, but is marked especially towards the extremity with streaks of black dots. Northern and (Jentral Europe, rather common ; (Sweden. Germany, Northern France, Belgium, England). 10.3-2. 1013. Hydaticus piceus, Lee, M.C. — Robustus, convexus, satlatus, sericeo-opacus, subtus piceus, supra fere unicolor, brunneus, limbo dilutiore. Long. 13, lat. 7 m.m. On the front tarsi of the male the fringing hairs are well developed, and the pal- ettes are large, those at the base being distinctly larger than the others, the claws are abruptly bent at the base ; the middle tarsi are broadly dilated, and bear a dis- tinct basal patch of glandular pubescence, besides the large palettes. The female has on the front of the thorax at some distance from each side, two or three coarse irregular impressions. This species is peculiar on account of its colour. Although it appears at first sight almost unicolorous above, yet on examination it is seen that the vertex is darker, and that in front of it there is an obscure arcuate dark mark, the disc of the thorax is also vaguely dark, and by careful examination there may be seen obsolete black dots or irrorations on tlie wing-cases, especially on the base and near the sides. The .silky opacity of the upper surface is peculiar and characteristic of the species. I have seen only a single pair. North America, (Pennsylvania, Illinois, sec. Crotch). 1018. 1014. Hydaticus parallelus, Clk., M.C. — -Elongatus, subparallelus, baud latus, nitidissimus, subtus piceus, vel piceo-niger, supra rufus, capite posterius nigro- signato, prothorace in medio transversim nigricante, el3'tris creberrime nigro-irroratis, versus suturam fere omnino nigris, punctis seriatis conspicuis; antennis jiedibusque anterioribus rufis, pedibus posterioribus piceis ; prothorace in medio canalicula brevi et tenui. Lono^. 14, lat. 7 m.m. This species is closely allied to Hydaticus capicola (No. 1043), but is more elongate and parallel in form, the distance between the anterior border of the hind coxa and the middle coxal cavity is rather greater, and the upper surface is appar- ently blacker and more shining, so that no traces of longitudinal lines of red colour can be perceived on the wing-cases. There are three series of black marks on the head, one in front of the other, these marks are connected at the sides, and occasionally in the middle also. The female has a few deep, coarse, short rugse on the thorax, on each side between the outer mai'gin and the middle. Australia, (New South Wales). 1001. 4 P i () J4 On Aquatic Carnivorous Coleoptera or Dytiscidce. Group 2. 1015. Dytiscus bimarginatus, Say, Hydaticus bimarginatiis, M.C. — Oblougo-ovalis, sat nitidud, niger, prosterno rufescente, capite thoraceque nifis, illo vertice, hoc basi, nigris, elytris prope latera vitta elongata huinerali testacea, ad apicem parum distincte testaceis, mavgine laterali rufescente ; aatennis pedibusque quatuor anterioribus rufis. Long. 11?, lat. G^ m.m. The male tarsi and their fringing hairs are moderately well developed, the middle tarsi are only moderately dilated, and have a very inconspicuous basal patch of glandular pubescence ; the female has some coarse impressions on the thorax towai'ds the sides. This species is generally broader in front and less dilated behind the middle, than H. rimosus, so that it is of more parallel form ; it is readily distinguished by the definite and regular sublatei'al yellow stripe on the wing-cases. It exhibits some sexual differences in form and colour, the females being generally rather narrower in front than the males, and they are liable to have the black colour of the thorax more extended and diffused, on the otiier hand they have the yellow sublateral band of the wing-cases more elongate. North America. 1031. 1016. Hydaticus rimosus, Aube, M.C. — Ovalis, nitidus, niger, prosterno anterius rufescente, capite thoraceque rufis, illo vertice et signatura inter oculos, hoc in medio, nigro-umbrosis ; elytris ad latera irregulariter testaceo-.signatis, signaturis illis mgro-irroratis ; antennis rufis, pedibus piceo-rufis. Long, llj, lat. 6 m.m. The male tarsi are moderately developed ; the female has some coarse impressions on the lateral parts of the thorax. In this species the limits between the black and red colours of the thorax are very indefinite, on careful examination it is seen that this black shading arises from a large basal black cloud, and from another discoidal cloud confused with it. The yellow marks on the elytra are irregular, indefinite, and variable, there is a small humeral mark having a greater or less extension backwards, the outer margin is yellow, and this yellow margin becomes reddish in front, but does not reach to the base, at the apex it is much dilated, and behind the middle it has one or two yellow small marks connected with it, when these yellow marks are lai'ge they are veiy irregular and much broken up by black dots or divisions, sometimes the humeral mark gives off in the direction of the scutellum the beginning of a transverse band. Cuba, Guadeloupe, Mexico. 1030. On Aquatic Carnivorous Coleoptera or DytiscidcB. 655 1017. Hydaticus rectus, n. sp. — Minor, ovalis, nitidus, subtus piceus, prosterno testaceo, supra capite thoraceque rufb-testaceis, illo vertice, hoc basi et iiiargiue anteriore elytrisque nigris, his fascia transversa pone basin margineque laterali late et reguiariter, testaceis ; antennis pedibusque quatuor anterioribus testaceis ; pedi- bus posterionbus rufis. Long. lOi, lat. 5f in.m. Tlie male tarsi are rather small, and their palettes are by no means large, and the fringing hairs are not very highly developed. I have seen only a single male of this little species ; the broad lateral yellow band of the wing-cases is very distinct and of nearly one width from the shoulder to the apex, it is however just a little dilated before the apex. It is ^mailer than the North American Dytiscus bimarginatus, and easily distinguished therefrom by the conspicuous yellow transverse fascia near the base of the wing cases, and the bright yellow red prothorax, with transverse black marks at the front and base. South America, (Parana). 1029. 1018. Hydaticus amazonicus, n. sp. — Reguiariter ovalis, fere elongatus, nitidis- simus, niger, prosterno anterius rufescente, capite thoraceque rufis, illo vertice et plaga inter oculos, hoc late in medio nigricantibus, elytris fascia transversa basali, linea humerali elongata, macula sublaterali pone medium alteraque subapicali testaceis, margin e laterali intra epipleuram anguste vageque rufescente; antennis pedibusque anterioribus testaceis, tibiis intermediis j^icescentibus. Long. 13, lat. 7i mm. This species is closely allied to H. subfasciatus, but is larger and mure elongate, the black colour on the Aving cases extends nearly to the apex, and the diminished extent of yellow colour appears but little dotted with black. I have seen only one individual ; it is a male and has the tarsi similar to those of H. subfasciatus, except that they are rather larger. South America, ( Upper Amazons). 1028. 1019. Hydaticus sulifasciatus. Lap., .M.C. — Ovalis, nitidissimus, niger, prosterno anterius testaceo, capite thoraceque rufis, illo vertice margineque interno oculorum, hoc basi in medio niaculaque ad marginem anteriorem nigris, elytris ex parte majore nigris, signatura humerali, fascia transversa pone basin, margine angusto antice abbreviato, macula irregulari ad latera paulo ultra medium apiceque late et confuse testaceis ; antennis pedibusque quatuor anterioribus testaceis. Long. 11, lat 6t m.m. The male front tarsi are not very large, but their fringing hairs and palettes are well developed : the female has a somewhat circular patch of fine dense sculpture on the thorax at some distance from each side. 656 On Aquatic Carnivorous Coleoptera or Dytisoidoe. The species is variable in colour, size, and form ; the lateral and apical parts of the elytra are more or less dotted with black in the yellow colour, and this is more conspicuously the case when the yellow is extensive ; the apical portion is generally very largely yellow ; the black marks at the base and front margin of the thorax are generally united along the middle. South America, (Guatemala, Panama, Cayeime, Amazonia). 1027. 1020. Hydaticus goryi, Aub6, Spec. p. 17.5. — Statura signaturisque variabilis; capite thoraceque rufis, illo vertice et inter oculos, hoc in disco et in medio ad basin nio^ris ; elytris nigris, margine externo, fascia pone basin signaturisque pone medium versus latera ssepe longitudinaliter disintegratis, testaceis ; subtus piceus, antennis pedibusque anterioribus rufis ; tarsorum posticorum ciliarum margine anteriore leviter arcuato, nuUo modo angulato. Long. 14*, lat. Si m.m. This is very closely allied to H. pacificus, and like it shows a very interesting (but different) series of variations ; perhaps it may be connected with H. pacificus, when specimens from other localities are examined, but at present it should be treated as distinct; on the thorax there is a development of the black colour on the disc rather than on the anterior margin, and when there is a dark spot on the front margin the discal cloud is largely dev^eloped in the transverse direction : on the lateral portions of the elj^tra the coloration is generally greatly broken up into dots or lines, and the ciliae on the hind margins of the joints of the posterior tarsi are so arranged that their tront margin forms a regular curve , while in H. pacificus this curve in the middle stretches very much farther in the anterior direction so as even to assume a subangulated form. A very peculiar and distinct variety is found in the Moluccas, it is small, and the elytra while largely black have the black colour much disintegrated into lines of black dots, and there is a complete absence of the transverse band of yellow colour near the base, and there is little or no tendency to the formation of a transverse band or spots of yellow colour behind the middle, (var. moluccarum). Another peculiar variety occurs in Batchian, it is also small, the elytra are very largely black, and the yellow transverse bands on the -wing cases are quite distinct, but are broken up by black dots and interruptions, (var. batchianensis). Australia; Malasia; New Caledonia; (Moreton Bay, Hunters River, Rockhampton). 1026. 10*21. Hydaticus bihamatus, Aube, M.C. — Statura signaturisque variabilis; capite thoraceque rufis, illo vertice et hoc in medio ad basin et ad apicem nigris; elytris nigris, margine externo, linea transversa pone basin, guttula laterali pone medium (versus suturam plus minusve extensa, et plus minusve disintegrata) signaturaque minore subapicali testaceis ; subtus piceus, antennis pedibusque On Aquatic Carnivorous Coleoptera or DijtiscidcB. 657 antei-ioribus rufis ; tarsorum posticorum ciliarum raargine anteriore semper valde arciiato, fere angulato. Long. 16, lat. 9i lu.ui. The male has the front tarsi largely developed, both fringing hairs and palettes being large ; the female sometimes has the thorax smooth, and sometimes its lateral portions bear numerous irregular impressions. The species is a very variable one, and shows numerous local but indefinite varia- tions. The commonest form is one of large size, in which the transverse band near the base of the wing-cases is slender, the lateral mark behind the middle is small and broken up into two or three spots, and the subapical mark is indistinct, all these yellow marks being more or less dotted with black. This form is found with greater or less extension of the yellow marks, in Malacca, the Philippine Islands, Andaman Islands, Celebes, Amboyna and Timor: and is the Hydaticus paciticus, Aube. The second form is much smaller in size, and has the yellow marks on the wing cases large and definite, the lateral yellow mark beyond the middle takes a great extension towards the suture, so that it forms a once or twice interrupted transverse fascia, the subapical mark is a distinct yellow spot. This form is the Hydaticus bihamatus of Aube, and is peculiar to the Philippine islands, but I have specimens from Malacca which quite connect it with the first form. The specimens from the Andaman Islands are a peculiar variety of the first form, being rather small, slender and depressed, with unusually slender posterior tarsi, and with a diminished development of the cilise on the hind margins of their joints. Malacca, Andaman Islands, Philippiues, Celebes, Amboyna. 1025. 1022. Hydaticus luczonicus, Aube, M.C. — Ovalis, satconvexus, capite thoraceque testaceis, illo vertice signaturaque inter oculos plus minusve discreta, hoc in medio ab apice ad basin nigricantibus ; elytris vix ex parte majore nigris, vitta transversa subbasali margineque laterali lato testaceis, margine hoc nigro-irrorato ; subtus nigro-piceus, pedibus quatuor anterioribus antennisque rufis. Long. 14i, lat. 8\ m.m. This species is very closely allied to the preceding, but is distinguished by its colour, the wing-cases bearing two longitudinal zones of colour of about equal areas, the inner one black, the outer yellow dotted with black ; the outer yellow zone of colour sends off near the base a transverse line which is continued towards the suture till it nearly reaches the scutellum. The female has some coarse impressions on the lateral part of the thorax. Philippine Islands ; India. 1024. 1023. Hydaticus dineutoides, n. sp. — Latus, subdepressus, niger, supra opacus, glaucus, vix senescens, clypeo breviter flavo, antennis rufis. Long. 15, lat. 8i m.m. 658 On Aquatic Carnivorous Coleoptera or Dytiscida. This peculiar species has the colour of a Dineutes a genus of Gyrinidre, and resembles a good deal some of the broader of those species in its form, except that it has the thorax shorter. I can find no structural character however to distino'uish it from the species of H3'daticus, although it has the epipleurte of the elytra broader. The only individual I have seen is a female and has no sculpture likely to be peculiar to its sex. The whole of the upper surface is dull and appears without scu]))ture, it is however very minutely punctured, the three series of punctures on the wing-cases can be seen, the inner however is the only one that is distinct, and the outer can scarcely be detected even with a very careful examination. Borneo. (Sarawak, found by the Mart[iiis J. Doria in 1865-'66, Genoa Mus.) 1023. 1024. Hydaticus Havolineatus, Boh., M.C. — Major, robustus, ovalis, subtus ferragineus vel piceus, supra capite thoraceque rufo-testaceis, illo vertice longe, hoc in marginibus anterioribus et posterioribus nigris ; elytris ex parte majore nigris, sed fascia pone basin transversa testacea, et colore nigro a lineis testaceis in lineas longitudinales nigras diviso, lineis his nigris prtesertim versus latera et ad apicem ab irrorationibus compositis. Long, 18, lat. 10 m.m. The fringing hairs of the front tarsi of the male are moderately long, and tlie palettes are large those at the base being specially large. Tlie female has a patch of rather fine net-like impressions on each side of the thorax at some distance from the outside. This species is conspicuous from its large size, and by the large extent of the black colour on the back of the head ; this black colour is transversely almost rectilinear in front and sliows no ti'ace of including any paler marks. According to the individuals before me it is a variable species, sometimes being much broader than at others ; the specimens from Natal are of rather narrow and elongate form, with the yellow lines of the elytra distinct although irregular ; the individuals from Arabia and Lake Nyassa ai-e broader, and the black colour on the elytra has more obliterated tiie yellow lines on the apical portions of the elytra, and the female has no peculiar sculpture on the thorax. The individual from Portuguese (juinea is on tlie other hand rather narrower and smaller than tlie Natal specimens, and the black colour on the wing-cases is rather differently arranged, the yellow lines on the basal portion being more obliterated, while across the middle the dark colour is more deficient, while it is again more predominant before the extremity, so that it has a tendency to be divided into two patches b_y an interrujition behind the middle. Africa and Arabia. (Natal, Lake Nyassa, Portugnese Ouinea ; Hedjaz;. 1022. JU25. Hydaticus decorus, Klug, M.C. — Uvalis, sat latus, nitidus, rufo-testaceus, vertice prcthoracc basi in medio elytrisque nigris, his margine externo anguste, signa- On Aquatic Carnivorous Coleoptera or Dytiscidce. 659 turisque disjunctis, testaceis ; pedibus posterioi'ibus robustis, tarsorum raarginibus posterioribus sat longe ciliatis. Long. Hi, lat. 8f m.m. This species is very similar to H. jucundus, but the yellow marks on the elytra are isolated from one another and less extensive, and the thorax is a little different, it being rather shorter and more curved at the sides near the posterior angles which are more rounded, it is more punctured near the sides and less evenly convex transversely ; so that in the form of the thorax the species makes a distinct approach to the peculiar Prodaticus pictus (No. 1005). The sexual characters both of the male and female seem to he quite the same as in H. jucundus, except that the female has no distinct impressions on the lateral part of the thorax, the surface there being, however, uneven and obscurely corrugated. Sinai, Egypt, Nubia. 1021. 1026. Hydaticus jucundus, Reiche, M.C.^Ovalis, sat latus, nitidus, rufo-testaceus, vertice prothoraceque basi in medio elytrisque nigi-is, his margine externo .signa- turisque irregularibus plus minusve trausversim dispositis testaceis ; pedibus posterioribus robustis, tarsorum marginibus posterioribus sat longe ciliatis. Long. 14i, lat. n m.iu. The male front tarsi are highly developed, the fringing hairs being very long, and the palettes large, the basal ones being particularly large ; the middle tarsi are somewhat broadly dilated : the female has some coarse irregular impressions on the lateral parts of the thorax ; in this sex there are some fine scattered punctures on the wing-cases, which are almost entirely absent in the male. The male has an im- pression at the apex of the last ventral segment, causing the hind margin to be depressed in the middle and to appear emarginate : the female has a longitudinal impression which reaches just as far as, but does not depass, the hind margin. This species seems to be somewhat variable in size and in the yellow marks of the elytra ; these marks especially near the sides and extremity are dotted with black. Abyssinia. 1020. 1027. Hydaticus dregei, Aubd, M.C. — Ovalis, parum latus et convexus, laevigatus, nitidissimus, rufo-testaceus, vertice, prothorace basi in medio elytrisque nigris, his signaturis irregularibus margineque externo testaceis; pedibus posterioribus sat gracilibus, tarsorum marginibus posterioribus baud longe ciliatis. Long. 13i, lat. 71 m.m. On the front tarsi of the male the fringing hairs are very highly developed and the palettes are of very unequal sizes, the basal ones, especially the posterior one, being of large size; the middle tarsi are only moderately dilated: the female has TRAN3. BOV. DUB. SOC. N.S., VOL. II. * Q 66U On Aquatic Carnivorous Coleoptera or DytiscidcB. some very short impressions on the hxteral parts of the thorax. The apex of" the last ventral segment is emarginate in the male, while in the female there is a small channel along the middle of the apical portion, terminating in an excessively minute emargmation. The species is remarkable by its highly polished surface, destitute of punctuation except tor the serial punctures of the wing-cases; the yellow marks of the wing- cases are much broken up, and very irregular and variable, and when they attain their greatest extent are, especially at the sides and apex, spotted with black. I have seen very few specimens. Aube was wrong in stating the front margin of the thorax to be black ; and also in describing the thorax of the female to be without impressions. His type from Dej can's collection is before me, and is in fact the only individual of that sex I have seen. Cape of Good Hope. 1019. 1028. Dytiscus grammicus, Germ., Hydaticus grammicus, M.C. — Ovalis, parum elongatus, sat latus et convexus, supra conspicue punctulatus, rufo-testaceus, vertice nigro, elytris nigro-irroratis, irrorationibus versus suturam in lineas longitudinales nigras a lineis flavis separatis condensatis. Long. 11, lat. 6h m.m. In the male the fringing hairs of the front tarsi are highly developed, and the palettes are rather large, the basal ones being a good deal larger than the rest. The female has the sides of the thorax roughened by short impressions. This is a species of rather short, broad and rounded form ; near the sides of the wing-cases the black colour is formed by nearly isolated dots, having however a more or less distinct linear arrangement, also at the base and apex of the elytra these black dots can be scan, towards the suture however the dots are condensed into dense black lines, separated by more or less distinct yellow lines of variable width. The species is also remarkable by its more than usually distinct punctuation. Europe and Japan; (AJsatia; Sardinia; Italy; Caucasus, sec. Cat. Munich). 1017. 1029. Hydaticus dorsiger, Aube, M.C. — Robustus, ovalis, sat convexus, subtus ferrucrineus, supra testaceus, vertice prothoraceque basi in medio nigris, elytris sat crebre ni»ro-irroratis, plaga communi suturali, elongata, nigra, antennis pedibusque anterioribus rufis. Long. I3i, lat. 8 m.m. The front tarsi of the male are large and highly developed, the fringing hairs being elongate, and the palettes large, those at the base indeed are very large ; the female has the lateral portion of the thorax covered with deep coarse connected impressions. On Aquatic Carnivorous Coleoptera or Dytiscidce. 661 This species has the black irrorations on the elytra smaller and less numerous than most of the allied species, and the longitudinal patch of black along the suture is therefore very conspicuous, in front it just reaches the extremity of the scutellum, but disappears some distance before the apex of the wing cases. There seems to be very little variation. Madagascar, Arabia. 1016. 1030. Hvdaticus matruelis, Clk., M.C. — Ovalis, sat elongatus, subtus ferrugineus, supra testaceus, vertice prothoraceque basi in medio nigris, elytris nigro-irroratis, fascia mediali irregulari transversa nigra, ante apicem fascia altera parum dis- tincta, antennis pedibusque anterioribus testaceis. Long. 13, lat. 7 m.m. On the front tarsus of the male the fringing hairs are highly developed, and the basal palettes are very much larger than the outer ones. The female has on the lateral parts of the thorax some isolated, short coarse impressions. This species is a good deal like the Australian H, cousanguineus (No. 1037), but is very much larger ; it is a rather elongate and but little convex species, and appears to be somewhat variable in colour; it has sometimes a dark mark on the head between the eyes, which at other times is scarcely to be detected ; the medial black fascia on the wing cases is not placed at all behind the middle ; the posterior fascia is very indistinct : the thoracic sculpture of the females is also somewhat variable. Western Africa, (Cape Coast Castle). 1015. 1031. Hydaticus concolor, n. sp. — Minor, angustulus, ovalis, nitidus, nigro-piceus, supra niger, capite anterius et in medio verticis rufescente, elytris versus latera pone medium macula rufa, antennis pedibusque anterioribus rufis ; pedibus pos- terioribus gracilibus, tarsorum marginibus postice breviter ciliatis. Long. 9, lat. 4f m.m. The male has no fringing hairs on the heel of the front tarsus, and the basal palettes are scarcely larger than the others. I have not seen the female. This peculiar little species is most like rlie dark form of H. fabricii (No. 1035), but is smaller and narrower*, it has the upper surface densely and more distinctly punctured than in the allies, and the hind legs are comparatively elongate and slender, with short cilise on the hind margins of the posterior tarsi ; it has a good deal the appeai'ance of a very minute Cybister, but I cannot find any structural characters to distinguish it from the allies near which I have placed it. Cochin China. 101 4. « 0* 662 On Aquatic Carnivorous Coleoptera or Dytiscidce. 1032. Dytiscus leander, Rossi. Hydaticus leander, M.C. — Ovalis, rufo-testaceus, vertice nigro, elytris creberrime nigro-irroratis, irrorationibus versus suturatn coalescentibus, pectoie, abdouiine pedibusque posterioribus ferrugineo-obscuris ; tarsis posterioribus robustis, marginibus postice parum longe ciliatis. Long. 11. lat. G ui.m. In the male of this species there are no fringing hairs round tlie heel of the front tarsus, and the basal palettes are hardly any larger than the others : the female has no peculiar sexual sculpture. This species is often placed in collections among the species of Rhantus ; although it bears a great resemblance to those insects in colour, size, and form, it mny be readily distinguished b}- the ciliation of the postei'ior margins of the hind tarsi. It varies somewhat in size and colour ; in the eastern part of its area, the thorax seems usually to be entirely red, and only a small part of the sutural area of the wing cases is rendered quite black by the coalescence of the dark irrorations ; in the south of Spain the individuals are of smaller size, and the thorax is black at the base in the middle, and the predominance of the black colour over the red on the wing cases is greater ; the difterences are not important and individuals from Corsica are generally intermediate. H. fusciventris, Reiche, (Ann. Fr. 185."', p, 639) from Palestine, is I believe also a variety of D. leander. Southern Europe, and Northern and Western Africa ; and Madagascar. (Nice, Corsica, Italy, Egypt, Nubia, Abyssinia, Algeria, Senegal, Portuguese Guinea, Gaboon). 1013. 1033. Hydaticus ponticus, n. sp. — Ovalis, breviusculus, rufo-testaceus, vertice breviter nigro, elytris creberrime nigro-irroratis vel vermiculatis ; tarsis posterioribus robustis, articulorum ciliis vix longis. Long. 9, lat. .5 m.m. The male has the fringing hairs round the heel of the front tarsus rather well developed, the basal palettes though not large, are distinctly larger than the others : the female has short obsolete impressions on the lateral parts of the thorax. The species differs from Dytiscus leander by its smaller size and shorter form, and by the developed fringing hairs of the male tarsi; it is also closely allied to H, rhantoides (Xo. 1036), but is considerably shorter in form, and the black irrorations on the elytra are denser and more confluent, and the cilire of the hind margins of the posterior tarsi, cover a very much smaller part of their area. It is still more closely allied to the variety found in India and Ceylon of H. fabricii (.\o. 1035) but it is considerably smaller, shorter in form, the surface is less shining, and the wing cases appear of a much blacker colour, owing to the greater confluence or condensation of the black irrorations. Mesopotamia. 1012. On Aquatic Carnivorous Coleoptera or Dytiscidoe. 663 1034. Hydaticus agaboides, n. sp. — Ovalis, posterius subrotundatus, nigro-piceus, ■capite prothoracisque lateribus testaceis, illo vurtice plagaque inter oculos nigris, elytris fere omnino nigris, versus latera testaceis ibidemque iiigro-irroratis, vel lineatis ; anteniiis pedibusque anterioribus testaceis, jjedilius posterioribus piceis ; coxis posterioribus abdomineque rugulosis ; tarsorum posticorum uiarginibus pos terioribus breviter ciliatis. Long. 82, lat. 5 m.m. This species seems closely allied to the darker form of H. fabricii, it is however rather broader than it, and more rounded behind, the under surface, instead of buiug smooth, is corrugated in a peculiar manner, especially on the coxo3 and the l)asal ventral segments, there is a dark mark between the eyes, and the ciliae on the hind margins of the joints of the posterior tarsi are quite short. I have seen only one individual, which is a female, and has a few sln)rt rugose impressions near the sides of the thorax. This individual is much suffused with dark colour, and it is pi'obable that in other individuals, the testaceous colour may be less concealed than in it. Cochin China. 1011. 1035. Hydaticus fabricii, Macleay, Ann. Jav. p. 134. — Species variabilis; minor, ovalis, parum convexus, subtus rufescens,plus minusve nigricans, supra rufo-testaceus, vertice nigro, elytris creberrime nigro-irroratis, irrorationibus versus suturam plus minusve coalescentibus ; tarsorum posticorum marginibus posterioribus sat longe ciliatis. Long. 10, lat. b\ m.m. In the male the fringing hairs round the heel of the front tarsus are short, and the basal palettes are only a little larger than the others ; the female has generally a. few short impressions on each side of the thorax. This species is very common in collections, and is widely distributed in the Izido- Malay region, and is very variable, the variations being to a large extent determined by the geographical habitat. The most distinct form occurs in the Malay jjeninsula; in it the outline is rather narrow and parallel, the colour very dark, owing to the predominance of the black spots causing the sutural region of the wing-cases to be largely quite black, the thorax is generally a little blackened at the base in the middle ; the fringing hairs of the male front tarsi are quite short, the posterior tarsi are rather slender, and the cilige of the hind margins of the joints occupy a comparatively small portion of the surface. In the continent of India and Ceylon a form differing much from the abu\c is found, it is rather larger and broader, the black dots of the elytra are evenly distri- buted and not confluent, the hind tarsi are shorter and stouter and the cilia; of their hind margins ar^ longer and occupy a larger portion of their surface ; the extreme individuals of this form are very similar to H. rhantoides, and are scarcely to be 664 On Aquatic Carnivorous Coleoptera or Diftiscidce. considered distinct from it but their hind tarsi are not quite so stout, and have not the cilise so largely developed. Besides these two extreme forms, a number of other less definite ones niaj be distino-uished, the above mentioned characters varying in degree of development and the manner in which they are combined ; the specimens from the Philippine Islands, Celebes, and the Andaman Islands, approach more or less closely to the Australian H. consanguineus. India, (Deccan) ; Ceylon, China, Penang, Malacca, Bangkok, Borneo, Sumatra, Andaman Islands, Java, Celebes, PhUippine Islands. 1010. 1036. Hydaticus rhantoides, n. sp. — Ovalis, subtus rufescens, supi-a testaceus, vertice nigro, elytris sequaliter nigro-irroratis ; tarsorum posticorum marginil)us posteriori bus longissmie ciliatis. Long. lOi, lat. 5| m.m. In the male the fringing hairs of the front tarsi are rather well develoj^ed, and the basal palettes ai'e distinctly larger than the others ; the female is almost entirely destitute of any sexual sculpture. This species is remarkably similar in size, form and colour to Dytiscus exoletus (Rhantus, No. 951), from which however a glance at the ciliae on the hind margins of the joints of the posterior tai'si will distinguish it. It is very closely allied to H. consanguineus, but it is usually rather smaller, of rather more rounded form, the black dots on the elytra are evenly distributed and not all confluent, and the fring- ing hairs of the male front tarsi are not quite so highly developed. Japan, Formosa, Mantchuria, China. 1037. Hydaticus consanguineus, Aub^, M.C. — Ovalis, s^jbtus rufescens, supra testaceus, vertice nigro, elytris crebre nigro-irroratis, irrorationibus in maculam vel fasciam discoidalem plus minusve discrete coalescentilius; tarsorum posticorum marginibus posterioribus Lmgissime ciliatis. Long. 11, lat. 6 m.m. In the male the fringing hairs of the front tarsi are highly developed and con- spicuous, and the two basal palettes are quite distinctly larger than any of the others;, the female is almost antirely destitute of any sexual sculpture. This species is slightly different in form from the allies, its greatest width being distinctly behind the middle of the wing cases. The tendency for the black dots of the wing cases to coalesce into a discoidal black mark may always be perceived, though in some cases it is very much more evident than in others. The ciliatiou of the posterior borders of the joints of the hind tarsi attains a great development, and the anterior limit of the ciliate portion of each joint is extremely arched. Australia and New Caledonia : apparently abundant. 1008. On Aquatic Carnivorous Coleoptera, or DytiscidcB. 665 1038. Colymbetes pulcher, Clk., M.C. — Ovalis, fere angustus.subtus rufo-obscurus, supra riifo-testaceus, capite verfcice plagaque transversa iuter oculos, prothorace ba&i margineque anteriore in medio plus minusve nigricantibus, elytris creberrime nigro-irroratis, irrorationibus versus suturam coalescentibus ; tarsorum posticorum marginibus posterioribus parum longe ciliatis. Long. 11, lat. 6 m.m. In the male the fringing hairs round the heel of the front tarsus are moderately well developed, and the basal palettes are distinctly a little larger than the others. This species is of rather more parallel and narrower form than most of its allies, and may be distinguished by the peculiarity that not only is the vertex black, but there is also a patch of dark colour between the eyes. The ciliation of the hind tarsi does not differ much from that of Hydaticus servillianus. I have seen but few specimens, and tliey vary somewhat in size, and in the extent of the black colour on the anterior margin of the thorax ; this is never very conspicuous, and seems to be less so in the male than in the female. In some individuals of this latter sex, some obsolete rugse or impressions may be observed on the lateral parts of the thorax, but in others they are quite absent. Australia, (Brisbane; Clarence River ; South Australia). 1007. 1039. Tlydaticus servillianus, Aube, M.C. — Ovalis, elongatus, rufo-testaceus, vertice nigro, elytris creberrime nigro-irroratis, irrorationibus versus suturam coalescentibus, pectore abdomineque picescentibus ; tarsorum posticorum marginibus posterioribus hand longe ciliatis. Long. 12, lat. G\ m.m. In the male the fringing hairs round the heel of the front tarsus are largely ■developed and conspicuous, and there is a good deal of variety in the size of the palettes of the undersurface, one of the two at the base being conspicuously large ; the female has some irregular very short impressions scattered on the lateral parts of tlie thorax. The species much resembles some of the varieties of Dytiscus leander (No. 1032), but is larger in size and moie elongate in form ; the male can be readily dis- tinguished from D. leander by the fringing hairs of the front feet, and the female by the presence of thoracic impressions ; the ciliation of the hind margins of the posterior tarsi is the same as in D. leander. I have seen but few specimens of this species, it seems to be rather variable in size, and in the amount of condensation of the black irrorations on the wing-cases, and sometimes the thorax appears black at the base in the middle. The thoracic sculpture of the females seems also to be somewhat variable. South Africa, (Caffraria, Cape of Good Hope). 1006. 1 040. Hydaticus palliatus, Aube, M.C. — Obion go-ovalis, robustus, sat convexus, subtus piceus, prosterno rufo, supra capite thuraceque rufo-testaceis, illo vertice 666 On Aquatic Carnivorous Colroptera or Dytiscidcu. signaturisque frontalibus. hoc plaga |)arva basali, nigris ; elytris ex parte majore nigris, lineis tribus testaceis ad basin plus tninusve distinctis, margine late irregulariter testaceo, nigro-irrorato ; antennis perlibusque anterioribus rufis, pedibus posterioribus piceis. Long. 14i. lat. 8 m.ra. 'I"he male tarsi seem scarcely to difter from those of Hydaticus capicola (No. 1013), the female seems at first to possess no peculiar sculpture, but there exists on each side of the thorax an indistinct patch of very fine and dense sculpture. The species seems to be a very variable one in size and colour, indeed in tliis latter respect it is not easy to find two indviduals quite similar ; sometimes the black marks on the middle of the head are well developed, at other times nearly entirely absent ; there is always a blackening of the base of the thorax in front of the scutellum, sometimes there is a more or less distinct, small dark mark on the middle of the thorax, and sometimes even the front margin is a little blackened. The amount of black on the elytra varies greatly ; generally the sutural portion is entirely black except at the apex, the outer margin and apex are always yellow, dotted with black, the boundary between the black sutui-al part and the pale outer part is generally very irregular and indefinite ; the black sutural part evidently arises from coalescence of the black dots, and in some cases it is absent, the elytra being dotted inore or less regularly with black ; in this case the yellow longitudinal lines are distinct, but where the black colour is very largely developed these lines can only be distinguished at the extreme base. H. incaustusand H. isabelli, Aub6, are both varieties of this species. South America ; (Brazil, Columbia). ](»41. Hydaticus sobrinus, Aube, .M.C. — Ovalis, sat latus et convexus, subtus piceus, prosterno testaceo, supra rufo-testaceus, capite, vertice signatura(]ue frontali et prothorace macula discoidali nigris, elytris creberrime nigro-irroratis, irroraticnibus plus minusve condensatis, ssepius fascia transvei'sa post medium sat distincta, antennis pedibusque anterioribus rufis, pedibus posterioribus piceis. Long. Ill, lat. 6l m.m. This species is very closely allied to Hydaticus capicola (No. 104.S', but is shorter in form, and has the legs shorter and stouter, the black mark on the thorax is usually less extended in the transverse direction, and the bla.'k dots of the elytra are confluent in a more or less irregular mannei'. The male characters are the same as in the two preceding species, and the female has deep rugae on the sides of the thorax as is the case in Hydaticus capicola. The amount of confluence of the black spots is variable ; nearly always an irregular black fascia behind the middle can be traced, but when the surface becomes very much blackened by extensive condensation, this fascia is, of course, less distinct ; the same remark applies to three yellow lines, or veins, on the On Aquatic Carnivorous Coleoptera or DytiscidcB. 667 elytra ; these can sometimes be seen, as is the case in Hydaticus capicola, but when the surface is very black can scarcely be traced. The serial punctures of the elytra are usually less distinct than in H. capicola, but in one individual from Mada- gascar they are as conspicuous as in the South African species : one female indivi- dual from Dejean's collection has the thoracic ruga? much obliterated. From South America 1 have seen only females, but cannot observe any good character to distinguish them from the Madagascar and Mauritian individuals. Madagascar; Maui-itius; Soxith America. lOOi. 1042. Hydaticus galla, Guer., M.C. — Ovalis, sat latus et convexus, subtus piceus, prosterno anterius testaceo, supra rufo-testaceus, capite posterius nigro-signato, pro- thorace disco signaturis parvulis subconjunctis fuscis, eiytris crebre nigro-irroratis, inter irrorationes lineis tribus vel quatuor vix conspicuis testaceis, antennis pedibus- queanterioribus rufis, jiedibus posterioribus piceis ; elytrorum punctis seriatis parum conspicuis. Long. 12^-, lat. 7 m.m. This species appears very closely allied to Hydaticus capicola, but is of less elongate form, the black irrorations on the elytra are less dense, the mark on the middle of the thorax is not a transverse line, but consists of some small closely placed marks, somewhat of a hieroglyphic appearance, the middle and hinder legs are shorter and stouter, and the female has no impressed rugse on the thorax. I have seen only four individuals of the species ; one of them (in the collection of the Genoa Museum) is a curious variety in which the black dots of the elytra behind the middle are condensed to form an irregular indistinct black fascia, behind which the black dots are more scanty so as to leave a pale fascia, behind that the dots are again condensed, and are again more scanty at the apex. Abyssinia, (found by Ilaffray). 1003. 1043. Hydaticus capicola, Aub^, M.C. — Elongato-ovalis, sat convexus, subtus piceus, prosterno anterius testaceo, supra rufo-testaceus, capite posterius nigro- signato, prothorace in medio plaga transversa nigra, eiytris crebrius nigro-irroratis, inter irrorationes lineis tribus vel quatuor vix conspicuis testaceis, antennis pedi- busque anterioribus rufis, pedibus posterioribus piceis ; elytrorum punctis seriatis conspicuis. Long. I3h, lat. 74 m.m. This insect has a great resemblance to the species of Rhantus (such as Colymbetes pulverosus. No. 924). The male has about twenty-two palettes on the undersur- face of the front tarsi, and about sixteen on the middle feet. The female has some moderately coarse, short ruga? or impressions, about the sides of the thorax. The species varies somewhat in size, and in the denseness of the black irrora- tions on the wing-cases, these, however, show very little tendency to the formation TRANS ROY. DUB, SOC, N.S., VOL. II. 4 R 668 On Aquatic Carnivorous Coleoptera or Dytiscidce. of black bands, they are conspicuously less numerous just at the apices ; of the three yellow lines or veins, the one running along the suture is the most conspi- cuous, the other two are sometimes only to be seen at the base, where the three are always united by a transverse prolongation. In two very small individuals (one from Cape Town the other from Natal) the thoracic dark mark is much reduced in size. South East Africa, from Cape Town to Abyssinia. 1002. Group 3. 1044. Hydaticus daemeli, (Wehncke), n. sp. — Ovalis, sat latus, parum convexus, nitidus, niger, capite anterius testaceo, et in vertice testaceo-bimaculato ; prothorace elytrisque ad latera testaceo-marginatis ; antennis pedibusque anterioribus rufis, tibiis intermediis piceis, pedibus posterioribus nigro-piceis ; elytris punctis seriatis conspicuis. Long. 14, lat. 8 m.m. This species appears to be a very distinct one ; the yellow band along the side of the elytra is somewhat irregular in its posterior half, being dotted with black and with its inner edge irregular ; at the apex however it quite reaches the suture. The species resembles somewhat the larger and flatter varieties of Dytiscus vittatus (No. 1049), but can easily be distinguished by the yellow band at the extremity attaining the suture. The posterior legs are short and thick, and the cilia3 of the hind margins of the joints of the posterior tarsi elongate. I do not know the male ; the female has a very few coarse rugae on the thorax near the sides. Australia, (Cape York). 1039. 1045. Hydaticus bivittatus. Lap., M.C. — Ovalis, parum latus, nitidus, capite anterius testaceo, posterius nigro, thorace testaceo, basi in medio nigro, elytris nigiis, margine laterali vittaque recta, integra, ad suturam sat approximata tes- taceis ; corpore subtus pi ceo, antennis pedibusque quatuor anterioribus rufis ; elytris punctis seriatis minutis, numerosis. Long. 14, lat. 7h m.m. In the male of this species the fringing hairs on the front tarsi are moderately well developed. The female sometimes has a few deep irregular impressions towards the sides of the thorax, but sometimes is without any peculiar sculpture. The position of the internal longitudinal band which is parallel with the suture and nearer to it than to the outer margin readily distinguishes this species from all varieties of Dytiscus vittatus (No. 1049) ; besides this the thorax is in greater part yellow, the ciliae on the hind margins of the posterior tarsi are much shorter, and the fringing hairs on the male front tarsi are longer than in D. vittatus. On Aquatic Carnivorous Coleoptera or Dytiscidce. 669 A variety occurs in which the yellow vitta is indicated only iu its basal and apical j)ortions. Madagascar, Jlauritius, Senegal, CafFraria. 1040. 104-6. Hydaticus rectangulus, n. sp. — Ovalis, sat latus, nitidus, capite anterius testaceo, posterius nigro, thorace in medio nigro, ad latera late testaceo, elytris nigris, vittis duabus latis integvis, interiore a sutura parum distante, testaceis ; corpore subtus piceo, antennis pedibusque anterioribus testaceis, tibiis intermediis pedibusque posterioribus piceis ; elytris punctis seriatis minutis. Long. 12i, lat. li m.m. This species is of the form of Dytiscus vittatus (No. 1049), but is readily distin- guished from it by possessing two broad longitudinal bands on the wing-cases ; the inner of the two is separated from the suture only by one-fourth, or less, of the breadth of the wing-cases ; moreover, at the base this yellow vitta has a small internal prolongation so that it nearly touches the scutellum. From Hydaticus bivittatus, the species is distinguished by its broader form, by the broader yellow stripes of the elytra, and by the shorter and thicker swimming legs, the hind mar- gins of the tarsal joints of which are moreover furnished with elongate cilise : also the external yellow band of the elytra, instead of continuing along the outer margin from the base to the apex, diverges from the outer margin a short distance behind the shoulder. A variety occurs in which the yellow bands are so broad as almost to be united into one large patch, the black vitta separating them being correspondingly diminished in size. Of the male I have seen only a single badly preserved individual, it appears not to differ in its tarsi from Dytiscus vittatus ; the female has no sexual sculpture. Persia, (Dr. Millingen) ; Northern India, (0. Boyd) ; (Kulu Kangra, Punjaub). 1041. 1047. Hydaticus duplex, n. sp. — Oblongo-ovalis, sat latus, capite anterius testaceo, posterius nigro, thorace nigro, ad latera testaceo, elytris nigris, vittis duabus integris testaceis, vitta interna, a sutura sat distante, pone basin cum fascia transversa flava fere ad scutellum extensa, coujuncta; corpore subtus nigro-piceo, antennis pedibus- que anterioribus testaceis, tibiis intermediis piceis, pedibus posterioribus fere nigris, elytris punctis seriatis sat conspicuis. Long. 14t, lat. 8 m.m. This species seems very closely allied to D. vittatus, but is rather larger than the longest individual of that species and is more oblong in form : the external yellow vitta of the elytra is continued to the extremity of the wing-case, while the internal one is towards the apex approximated a little nearer to the suture than it is in D. vittatus, and moreover sends off near its commencement an internal prolongation 4 B t 67u On Aquatic Carnivorous Coleoptera or Dytiscidce. which nearly reaches the scutellum. In other respects the s^aecies agrees closely with D. vittatus. I have seen only a single male. Borneo. 1042. 1048. Hydaticus bowringi, Clk., M.C. — Ovalis, latus, convexus, capite anterius testaceo, posterius nigro, prothorace testaceo basi transversim in medio, margineque anteriore in medio, nigris, elytris perspicue punctulatis, nigris, vittis duabus elongatis punctoque rotundato prope scutellum testaceis ; corpore subtus ferrugineo, antennis pedibusque anterioribus testaceis, tibiis intermediis piceis, tibiis tarsisqae posteriori- bus nigris. Long, 14, lat. 9 m.m. This species seems closely allied to Dytiscus vittatus, but is rather larger and broader, it is paler beneath, and has the punctuation of the elytra coarser, the thorax is in greater part yellow, the external yellow stripe on the elytra is more elongate and the inner one is nearer to the suture, and there is always a conspicuous yellow spot near the scutellum. In most other respects it resembles the well known D. vittatus. The male tarsi are much the same in the two species, except that in H. bowringi the fringing hairs on the anterior feet are rather better developed : the female has an indefinite patch of dense fine sculpture on each side of the thorax. Sometimes the external yellow stripe of the elytra is a little abbreviated and then does not connect with the inner stripe, it alwaj's however extends much beyond the middle. Japan, China, (Che-fou), (Australia? teste Clark). 1043. 1049. Dytiscus vittatus, Fab., Hydaticus vittatus M.C. — Ovalis, sat latus et convexus, niger, capite anterius prothoraceque ad latera testaceis, elytris vitta elongata cum margine externo parallela testacea, aliaque humerali abbreviata stepius cum vitta elongata ad dimidiam partem longitudinis conjuncta ; antennis pedibusque anterioribus testaceis, tibiis intermediis piceis, femoribus fusco-testaceis. Long. 12, lat. 7 m.m. In the male of this species there are about twenty-two palettes on the underside of the not very large front tarsi, and the fringing hairs round the base are short : the intermediate tarsi have the thi'ee basal joints moderately incrassate and bearing beneath two series of small palettes, these series are separated by a distinct glabrous space or line, and the inner of the two series is rendered irregular by the addition of a supernumerary palette near the base ; these palettes are about fifteen in number altogether. The females have generally a patch of sexual sculpture on each side of the thorax, this however is very variable in its character and is sometimes entirely wanting : in On Aquatic Carnivorous Culeoptera or Dt/ttscidce. 671 certain individuals there are quite distinct short irregular impressions, while in other cases there is in the same situation only a more dense and, perhaps, rather coarser jjunctuation, while often there seems to be no departure from such punctuation as exists in thu male. The species is easily recognised by the yellow vitta running parallel with the outer margin of the wing case, and extending from the base to near the apex, but not there attaining the suture ; and by the short additional humeral vitta : both these stripes are subject to some variations, the elongate one is sometimes inter- rupted, or broken up, and, very rarely, nearly entirely absent ; the outer yellow stripe also varies somewhat ; it is often so confluent with the more elongate stripe that the two have the appearance of one stripe enclosing a small humeral black mark : this black mark may become more elongate so that the junction of the two yellow stripes occurs only just behind the middle ; in other cases the short humeral stripe does not join the inner stripe at all, but is terminated just before the middle. The species also varies somewhat in size and form : it has always the ciliae of the hind margins of the joints of the posterior tarsi very largely developed, but even this is subject to a little variation. The variations are to some extent, but only slightly, dependent on geographical distribution ; the most marked instance of which is that the specimens in which the short humeral yellow stripes on the wing- cases remains quite ununited with the longer stripe, occurs chiefly in Australia : similar individuals occur, however, in Siam and the Malay peninsula, and every grade of intermediate character may be found. A variety from the Philippine Islands has the inner yellow stripe represented only by a spot of that colour near the apex of the wing-cases, the humeral stripe being on the other hand a little longer than usual, this has been recently described as a distinct species (H. bipunctatus, Wehncke). This species is very ^videly distributed in the South Eastern parts of the Old Worhl. Japan, Mantchuria, Formosa, China, East India, Ceylon, Malacca, Siam, Java, Boi-neo, Sumatra, Celebes, Philippine Islands, Labuan, Batchian, Menado, and Australia (North, South, and "West). 1044. 1050. Hydaticus exclamationis, Aub^, M.C — Ovalis, sat latus et convexus niger, capite anterius prothoraceque ad latera testaceis, elytris vitta elongata lateral! testacea ; antennis pedibusque anterioribus testaceis, pedibus posterioribus piceis. Long. 13i, lat. 8 m.m. This species difiers from Dytiscus vittatus, inasmuch as the short humeral stripe of the elytra of that species is in the present one extended to the extremity of the wing-cases, while the inner stripe is entirely wanting ; besides this the cilias on the hind margins of the joints of the posterior tarsi are much shorter, and the fringing hairs at the base of the anterior tarsi of the male are considerably longer than in 672 On Aquatic Carnivorous Coleoptera or Dytiscidcs. Dytiscus vittatus. I have seen but few specimens, and it is quite possible that ultimately the two supposed species may prove not to be distinct. Madagascar, and Portuguese Guinea. 1045. 1051. Hydaticus petitii, Aube, M.C — Oblongo-ovalis, sat latus, niger, capita anterius prothoraeeque ad latera testaceis, elytris vitta elongata laterali testacea ; antennis pedibusque anterioribus testaceis, tibiis intermediis piceis, pedibus pos- terioribus piceo-nigris. Long. 16, lat. 9 m.m. I see nothing to distinguish this species from H. exclamationis except the larger size, and more oblong form. It appears, moreover, to be variable, the yellow band of the elytra being sometimes very broad and conspicuous, and in other cases much reduced ; the colour of the undersurface and the legs also varies in depth. The largest individual I have seen is from Madagascar, while the smallest — the one in which at the same time the yellow band is most reduced — is from South Africa. Madagascar, Abyssinia, South Africa. 1046. II. 14. — Group Therjionectini. Episternal suture distinctly curvilinear ; spurs of hind tibiae minutely emargin- ate at the apex. The six genera constituting this group luay be readily identified by the following abbreviated characters : — Elytra closely punctate (in the other members of this group the elytra are im- "I A CI LITIS. punctate, except occasionally there is a sexual sculpture in the female. \ ( Yiih below.) Cosal lines distinct ; supra-articular border broad ; middle femora Tnth \ TIIERMOXECTES. elongate setse. | {Vide ^. G77.) Coxal lines distinct; supra-articular border broad; middle femora wth ) (ETHIONECTES. short setae ; prosternum strongly elevate-compressed along the middle. j ( Vide p. 684.) Coxal lines obliterated so that no supra-articular border is present ; middle ) SANDRACOTTUS. femora -with moderately long setfe. j {Vide ^. 685.) Coxal lines obliterated so that no supra-articular border is present ; middle \ EHANTATICUS. femora with qiiite short spines. | {Vide ^p. 691.) Coxal lines fine but yet distinct ; supra-articular border moderately broad ; ) GRAPHODERES. middle femora -vvith rather short stout setas. ' / (Fit/e p. 692.) I. Q9.—Gems ACILIUS. Elytra punctate ; coxal border distinct, but not very broad. The six species of this genus are peculiar to Europe and North America. On Aquatic Carnivorous Coleoptera or Di/tiscidce. 673 1052. Dytiscus sulcatum, Lin., AcUius sulcatus, lif.C — Latus, supra parum con- vexus, capite prothoraceque testaceis, signaturis transversis nigris, elytris fusco testaceis, nigro-irroratis, subtus prosterno testaceo, pectore abdomineque nigris, hoc lateribus marginibusque ftavo-signatis, pedibus anterioribus testaceis, poste- rioribus basi, tibiis tarsisque nigricantibus ; corpore creberrime punctato : antennis elongatis tenuissimis. Long. 16, lat. 10 m.m. Mas, parum nitidus, corpore superne creberrime punctato. Fem., protborace medio utrinque versus latei'a subimpresso ibidemque villoso, elytris sulcis latis viilosis integris. In the male the three basal joints of the front tarsi are greatly dilated, the basal joint is large, and bears beneath a single very large cupule, the other two joints are very short ; the undersurface of the tarsus beai's besides the large cupule two much smaller cupules, and externally two patches of dense hairs bearing very minute palettes ; the fringing hairs are elongate and beautifully developed. The middle tarsi are not incrassate, but still are a little thicker and have the two apical joints more elongate than in the female ; the three basal joints have their inner and lower edge armed with a tuft of long hairs, of which the basal one is most highly developed ; their undersurface has close to the marginal setse a few hairs bearing minute palettes. In the female the grooves on the elytra are elongate and very broad, they commence very near indeed to the base, and are continued nearly to the apex, the inner one is, however, shorter than the one next it, the termina- tion of this furrow also is more gradual than that of the others, so that its length at the apex is slightly variable. The black marks on the head of this species may be said to be three in number, one in front of the other — viz., the vertex is black, and there is an angular black mark in front of it, and at the sides connected with it, while the third and most anterior mark is a triangular black patch, whose outer and front angles reach the clypeal suture. The thoracic black mark consists of two lines across the middle, more or less connected at their extremities. The species varies in the extent to which the black colour of the upper surface is developed, and in Scotland a variety is found in which the upper surface is nearly entirely black. Europe ; from Sweden and Finland to Spam, Russia. 956. 1053. Dytiscus fasciatus, de Geer, Acilius fasciatus, M.C. — Sat latus, supra parum convexus, testaceus, capite prothoraceque signaturis transversis nigris, elytris fusco-testaceis, nigro-irroratis, subtus pectore nigricante, abdomine plus minusve nigro-fasciato ; pedibus posterioribus rufescentibus ; corpore creberrime punctato ; antennis elongatis tenuissimis. Long. 15i, lat. 9i m.m. Mas, parum nitidus, corpore superne crebenime punctato. 674 On Aquatic Carnivorous Coleoptera or Dytiscidce. Fern., elytris sulcis latis, villosis, integris. The male characters in this species are the same as in l)3'sticus sulcatus. The species indeed is very closely allied to the D. sulcatus, but remains always perfectly distinct ; it is smaller, and appears narrower, the anterior of the three black marks on the head is wanting, the black colour is less developed on the ventral segments, and the liind legs have the femora entirely yellow, and the tibiae and tarsi more or less rufescent, never black. In the female there is very slijj;ht development of the pubescence on the thorax, and the third furrow is narrower, owing to the elevation which limits it externally being more deflected from a straight course than it is in D. sulcatus ; and the furrows, especially the inner one, are continued a little nearer to the apex. The species varies in the colour of the lower surface, which is sometimes entirely yellow. Eui-opeaad Siberia; from Sweden and Finland, 68° 30' (Sahlberg), to Spain. 1054. Acilius semisulcatus, Aub^, Spec. p. 132.— Vix latus ; supra parum convexus, testaceus, capite prothoraceque signaturis transversis nigris, elytris creberrime nigro-irroratis pone medium fascia pallida plus minusve distincta ; subtus pectore nigro, abdomiue nigricante, maculis lateralibus fasciisque transversis testaceis, pedibus testaceis, femoribus posterioribus basi plaga nigricante ; corpore creberrime punctato ; antennis elongatis, tenuissimis. Long. 13, lat. 7i m.m. Mas, parura nitidus, elytris creberrime punctatis. Fern., elytris sulcis latis setulosis, ad basin plus minusve abbreviatis, suturali semper breviore. The male has the front tarsi much as in the preceding species ; on the middle tarsi the tufts of hairs at the inner edge of the three basal joints are elongate and distinct, but there is never any development of small palettes on the lower surface. The larger specimens of this species present a great resemblance to the smaller ones of D. oanaliculatus. A. semisulcatus is, however, narrower, and has the epipleurae considerably less developed, and the cilias at the posterior margins of the joints of the hind tarsi more elongate. The species shows a gi-eat deal of variation. The form ordinarily found in the Eastern United States may be considered as the typical one ; the specimens from these parts differ only moderately in size, colour, and sculpture, except that a variety occurs in which the whole of the lower surface is clear yellow. Tn North- west America there is found a form appearing at first very distinct, and making the greatest approximation to the European D. canaliculatus. These specimens are larger, more particularly the females, and the individuals of this latter sex have the three outer grooves continued almost to the very base of the elytra, while the costse between the grooves are naiTower and more abruptly defined, particularly in front, and the punctuation near the sides of the thorax is rougher ; in the males On Aquatic Carnivorous Coleoptera or Dytiscidce. 675 the punctuation of the wing-cases is not so dense as in the typical individuals. These characters become more or less modified in Californian specimens, and in the broader and shorter individuals from this part of the Pacific district the resemblance in form to Dytiscus fraternus is very great, and is accompanied by a great extension of the black mark of the hind femora. A variety of this Californian race has, however, the undersurface and hind femora entirely yellow. Crotch states that a form of the female without grooved elytra occurs, but I have not seen such, the variation tending, when departure from the type is made, in the direction of greater extension of the grooves, and I suspect that the individuals alluded to by Crotch should have been rather referred to Dytiscus fraternus. The variations of the species, as given by Crotch, are : — Var. simplex, Lee. Posterior femora piceous, knees yellow ; female with the elytra smooth. San Diego. Var. oregonensis. Elytra paler, more thinly irrorated with black, fascia paler and more distinct, posterior femora pale. Oregon. Var. latiusculus, Lee. Testaceous beneath, sulci of $ as in type. Var. abbreviatus, Man., Aube. Larger, femora testaceous, sulci in the female almost reaching the base. North America. Very -nddely distributed fi-om Sitka to Haiti. 958. 1055. Dytiscus fraternus, Harr., Acilius fraternus, M.C. — Supra parum convexus, testaceus, vertice prothoraceque signaturis transversis nigris, elytris creberrime nigro-in-oratis fascia transversa pallida parum distincta, subtus pectore abdomineque nigris, hoc minus testaceo-variegafco ; femoribus posterioribus nigri- cantibus : corpore creberrime punctate ; antennis elongatis, tenuissimis. Long. 14, lat. 8 m.m. Mas, subopacus, elytris creberrime punctatis. Fern., elytris sulcis latis, setulosis, ad basin valde abbreviatis, suturali paulo breviore. This species has the male characters the same as in Acilius semisulcatus, except that the three tufts of hairs on the intermediate tarsi are much less developed, and appear indeed on a hasty inspection to be entirely wanting. The species is very closely allied to A. semisulcatus, but the anterior border of the hind coxa is always separated by a longer space from the middle coxal cavity. Besides this the species is usually rather broader, darker in colour, and more densely punctured, and the furrows on the elytra of the female are more abbreviated in front. A variety of this latter sex occurs in which the elytra are, like those of the male, without grooves. The species varies somewhat in the colour of the upper surface, especially in the TRAXS. ROT. DCB. SOC, N.S., 'VOL. H. 4 g 676 On Aquatic Carnivorous Coleoptera or Dijtiscidce. greater or less distinctness of the pale band of the elytra : underneath the amount of the yellow colour on the ventral segments shows a good deal of variation. North America, (Massachusetts, New York, Pennsylvania, Illinois). 959. 1056. Acilius duvergeri, Gobert, Ann. Soc. Ent. Fr. (.5) IV, p. 441. — Haud latus, subdepressus, testaceus, capite thoraceque signaturis transversis nigris, elytris creberrime nigro-irroratis, pectore nigro ; thorace impunctato, parum nitido, elytris subrugoso-punctatis, ad suturam versus basin fere Isevigatis ; corpore subtus minus punctato, parum nitido. Long. 13, lat. Ik m.m. The male has on the undersurface of the very broad front feet three large palettes differing little from one another in size, and outwardly a patch both in front and behind of minute palettes borne on hairs, the fringing hairs are highly developed ; on the middle feet the tarsi are not dilated, but the basal joint bears beneath several small palettes; of the two females before me one has the sculpture of the elytra the same as in the male, while in the other it is a good deal denser and more rugose. Europe. Ihis species has only been found yet at Dax in the south-west of France. This excessively limited distribution of a species is very remarkable. 960. 1057. Dytiscus mediatus. Say, Acilius mediatus, M.C. — Haud latus, parum convexus, nitidus, subtus niger, prosterno in medio testaceo, supra testaceus, capite thoraceque nigro-signatis, elytris creberrime nigro-irroratis, fascia pone medium maculisque apicalibus sat distinctis pallidis, pedibus anterioribus testaceis, poste- rioribus nigris ; elytris crebre, versus basin parce subtiliter punctatis, punctisque seriatis sat distinctis; coxis posterioribus parce, distincte punctatis. Long. Ill, lat. 6^ m.m. The male has the front tarsi smaller than in Acilius semisulcatus ; beneath with three palettes of moderate size and not differing much from one another, and out- wardly with two patches of palette-bearing hairs, the fringing hairs but little developed ; the intermediate tarsi are quite simple, without any peculiar clothing. I have seen very few specimens of this interesting species. According to the individuals before me, there is probably a slight difference in the sculpture of the thorax in the two sexes : in the male on this part there are very few punctures, and they are so small as easily to escape attention, in the females they become a little more distinct at some distance from each side. North America (Nebraska, Pennsylvania, Georgia, sec. Crotch). 961. On Aquatic Carnivorous Coleoptera or DytiscidcB. 677 I. 70.— Genus TIIERMONECTES. Coxal lines distinct in their hinder portion ; supra-articular border broad ; elytra not punctate (except for a sexual sculpture in certain females). Middle femora with elongate setpe. The species'^ may be arranged in three artificial groups : 1. Elytra (at any rate on the basal portion) yellow with numerous black specks, after the manner of Rhantus. Nos. 1058 to 1064. 2. Elytra black, with definite yellow markings forming conspicuous spots or fasciae, but no minute speckles. Nos. 1065 to 1070. 3. Elytra black, with irregular marginal yellow marks which are of a longitudinal character and more or less divided by black lines and specks. No. 1071. Group 1. 1058. Acilius nigrofasciatus, Aube, M.C. — Robustus, nitidus, lasvigatus, elytris punctis seriatis sat conspicuis, subtus rufo-testaceus, supra testaceus, vertice thoraceque transversim nigro-signatis, elytris nigro-irroratis, pone medium fascia lata transversa, Integra, perconspicua nigra. Long. IH, lat. 7 m.m. Mas, lajvigatus, nitidus. Fem., elytris ad basin prothoraceque utrinque punctis elongatis, rudis impressis. In the male the three larger palettes on the underside of the front feet, are of about one size. This species is extremely closely allied to the following, but is perhaps really distinct, it is rather larger and comparatively broader in front, and has the black fascia on the wing-cases excessively broad and conspicuous, and with no trace of any interruption ; these are all the points I can find to distinguish the male, but the female is very easily distinguished by its more conspicuous sexual sculpture ; the elytra bear on their basal half coarse and deep short impressions or elongate punctures, they extend all across the base of the wing-case from the scutellum to the shoulder, and are also quite conspicuous on each side of the thorax. I have seen but few specimens of this species ; the thoracic black marking is no doubt variable, generally it consists of two transverse black lines, more or less united at their outward termination, and separated from one another by about the * The descriptions mentioned in the following list also refer to this genus. Acilius cinctatus, Aube (No. 1172 huj. op.), near No. 1070 ; Mexico.— Acilius laporti, Aube (No. 1174) near No. 1059 ; Brazil. — Acilius laticinctus, Lee. (No. 117.5) near No. 1071 ; California. — AcUius maciilatus, Aube (No. 1176) near No. 1059; Mexico. — Thei-monectes intermedius, Crotch. (No. 1508)? No. 1071 var. ; California. 4 S 3 678 On Aquatic Carnivorous Coleoptera or Dijtiscidce. same distance as the front one is from the front margin, and the hind one from the base ; in one of Aube's type specimens, these black marks however are somewhat diminished. Mexico. 962. 1059. Acilius ornaticollis, Aub^, M.C. — Parum latus, nitidus, Isevigatus, elytris punctis seriatis sat conspicuis, subtus rufo-testaceus, su})ra testaceus, vertice thoraceque transversim nigro-signatis, elytris nigro-irroratis, pone medium fascia transversa plus minusve conspicua nigra. Long. 11^, lat. 6i m.m. Mas, Isevigatus, nitidus. Fern., nitida, elytris ad basin in medio punctis elongatis sat subtilibus impressis. This species varies considerably in size, in the black marks of the upper surface, and somewhat in the sculpture of the females. Ihe black marks on the thorax consist of a transverse line very near the front margin, and of a second one just behind the middle, this latter often more or less connected with a black basal line ; the front line is generally slightly interrupted in the middle, and is liable to be very much diminished, even broken up into three or four dashes ; the post- medial mark is more or less distinctly biarcuate ; and the basal black mark is sometimes quite absent. When these marks are very largely developed, the front one scarcely leaves any yellow colour at the front margin, and is connected at the sides with the post medial mark, and this latter may be nearly entirely confluent with the black basal mark. The elytra are sometimes much more covered with the black colour than at others, and the post-medial black band, never very con- spicuous, can occasionally be scarcely detected. The impressed short lines on the wino'-cases of the female are sometimes a little coarser, and their extension in the posterior direction is a little variable, but there is never any indication of their presence on the prothoi-ax. North America, (United States and Mexico.) 9G3. 1060. Acilius succinctus, Aub^, M.C. — Sat convexus, nitidus, Isevigatus, elytris punctis seriatis sat conspicuis, prosterno ex parte majore testaceo, abdominis lateribus flavo-maculatis, supra testaceus, vertice prothoraceque transversim nigro-signatis, elytris nigro-irroratis, pone medium fascia transversa nigra, pedibus anterioribus testaceis, posterioribus rufescentibus, temoribus basi tibiisque extus nigricantibus. Long. Ill, lat. 6^ m.m. Mas, nitidus, lasvigatus. Fem., nitida, elytris ad basin punctis elongatis rudis impressis, prothorace utrinque punctis parum conspicuis. 0)1 Aquatic Carnivorous Colcoptera or Dytiscidce. 679 In the male, the most basal of the three largtir palettes on the underside of the front feet is considerably larger than the other two. The black marks on the thorax are less extensive than in the allied species, the anterior one is placed a little behind the front margin, and is not interrupted in the middle even when most diminished, and is never connected with the posterior marks, which consist of two very closely placed lines joined at their extremities so as to enclose a yellow transverse line which is most frequently divided in the middle ; when the black marks take a greater extension than usual, this enclosed yellow line may be entirely absent. The sjiecies varies much in size, and somewhat in the relative amounts of the black and yellow colours ; and in the smallest females the sexual sculpture is nearly entirely absent ; the punctures on the thorax ajjpear however to be not quite so variable as the more conspicuous sculpture on the elytra. South America, Mexico, (Bahia, Petropolis, Para, Peru.) 964. 1061. Dytiscus circumscriptus, Latr., Acilius circumscriiJtus, Jl.C. — Convexius- culus, parum latus, Itevigatus, nitidus, subtus niger, prosteruo ex parte majore testaceo, supra testaceus, vertice nigro-signato, thorace anterius et posterius in medio nigro, elytris nigro-irroratis, irrorationibus post medium in fasciam transversam nigram condensatis, et post fasciam irregularibus, antennis pedibusque anterioribus testaceis, pedibus posterioribus extus nigris, femoribus externe late rufescentibus ; elytrorum epipleuris angustis. Long. Hi, lat. 6| m.m. Fern., elytris in medio longitudinis j)unctis elongatis subtilibus impressis, pro- thorace versus latera punctis impressis minus subtilibus. In the male the tliree larger palettes of the undersurface of the front tarsi are of about one size, and not very large. The fine impressed linear punctures on the wing-cases of the female form a broad patch extending from the base about two- thirds of the length of the elytra. In this species the transverse black mark on the thorax always attains respec- tively the front and hind margins, and so leaves yellow across the middle only a short stripe between them. The species varies a good deal in size, and in the greater or less condensation of the black spots of the upper surface, occasionally the sides of the hind body are obscurely spotted with yellow. The sculpture of the female is evidently variable, for there exists in Dejean's collection an individual of that sex, which shows no trace of the impressions on the elytra, and very little of the thoracic punctuation. Widely distributed in the New World, from Mexico aud the Antilles to Monte Video. 965. 1062. Thermonectes depictus, (Reiche), n. sp. — Convexiusculus, latiusculus, laevigatas, nitidus, subtus piceus, prosterno anterius rufescente, supra testaceus, GSO On Aquatic Carnivorous Coleoptera or Dytiscidce. vertice nigro-signato, thorace anterius et posterius in medio nigro, elytris nigro- vermiculatis post medium nigro-fasciatis, post fasciam pallidioribus, pedibus anterioribus testaceis, posterioribus rufescentibus, tibiis nigricantibus ; elytrorum epipleuris vix latis. Long. 12, lat. 7 m.m. Fern., elytris in medio partis basalis punctis subtilibus impi-essis. In the male of this species the three larger of the palettes on the front feet difier but little in size from the others. The species is very similar to Acilius circumscriptus, but is broader in front, and the black marks on the thorax do not extend so near to the sides ; and the yellow colour on the wing-cases bears a larger proportion to the black colour, the epipleurye are decidedly broader, and in the female the very fine punctures on the wing-cases do not extend so far backwards, and there are none on the thorax. I have seen but very few individuals ; they show some variation in the colour of the under surface which is sometimes blacker, sometimes redder. South America, (Columbia). 9GG. 1063. Hydaticus vaviegatus, Lap., M.C. — Convexiusculus, latiusculus, lajvigatus, nitidissimus, subtus niger, prosterno anterius flavescente, supra nigro testaceoque variegatus, capite anterius et ante verticem testaceo, prothorace in medio et ad latera testaceo, anterius et posterius nigro, elytris ad basin nigro- variegatis, pone medium fasciis irregularibus a fascia lata nigra separatis testaceis. humeris plaga intus a plaga nigra limitata testacea ; pedibus anterioribus testaceis, posterioribus plus minusve nigricantibus, epipleuris latis. Long. 13;, lat. 8 m.m. Fern., nitida, elytris ad basin lineolis brevibus numerosis impressis, prothorace litrinque sparsim lineolato-punctato. In this species the anterior black mark on the thorax is broad, but does not reach the sides, at its termination it emits a prolongation backwards ; the hinder black mark reaches to the hind angles, but is there very short. The elytra have a humeral patch quite yellow, and this patch is limited inwardly by a black mark ; the rest of the basal portion of the wing case is black, marked with numerous small yellow marks, which become more indistinct on the middle part which is, therefore, nearly entirely black, behind this black point is a variable, irregular, transverse fascia of yellow, interrupted at the suture, behind this the colour is again quite black, while just before the apex there is another very irregular, interrupted yellow fascia. I have seen very few specimens of this species. South America, (Brazil; Amazons, Eio Sappo., 21. 11. 1874, from water standing in a canop, Dr. Trail). 967. 0)1 Aquatic Carnivorous Coleopiera or Dytiscidce. 681 1064. Thermonectes simulator, n. sp. — Ovalis, baud latus, transversim convexus, Isevigatus, nitidisslmus, subtus niger, supra nigro testaceoque variegatus, thorace anterius et posterius conspicue nigro-lineato, elytris eequaliter nigro-vermiculatis, autennis pedibusque anterioribus rufis, pedibus posterioribus nigricantibus, femori- bus ad apicem rufescentibus ; elytrorum epipleuris per-angustis. Long. 14^ lat. 8i m.in. Fern., pernitida, elytris versus basin in medio sparsim vix perspicue punctatis. This species is remarkable inasmuch as the coloration of the upper surface rej^eats almost with perfect exactness, that of the European Dytiscus cinereus (No. 1088). In the male the smaller palettes on the undersurface of the front tarsi are largely developed, while the three larger ones are of rather small size, and differ but little in size inter se, so that they present but a slight contrast with the smaller palettes. The sexual sculpture of the female is so slight that it will be overlooked without a careful examination. I have seen only one pair of this remarkable Thermonectes. South America, (Parana). 077. Group 2. 1065. Acilius duponti, Aube, M.C. — Convexus, sat latus, laevigatas, nitidus, niger, capite anterius et in medio verticis, prothorace ad latera fasciaque parum extensa in medio, elytris plaga humerali, maculis basalibus, fascia submediali aliaque subapicali interrupta, antennis pedibusque anterioribus testaceis ; epipleuris latis. Long. 13i, lat. 7f m.m. JFem., nitida, elytris in medio ad basin lineolis brevibus impressis. I have seen only a single individual of this species, which seems allied both to Hydaticus variegatus (No. 1063), and Dytiscus interruptus : it is more narrowed in front than the former, but not so broad behind the middle as the latter. The yellow colour on the thorax is much diminished in its extent, the anterior black mark having its termination jointed to the posterior one, so that the slender line of yellow enclosed by these two marks is isolated from the lateral patch of yellow. Soutii America, (BrazU). 968. 1066. Dytiscus interruptus, Sturm., Acilius interruptus, M.C. — Latus, anterius conspicue angustatus, subtus convexiusculus, Isevigatus, nitidus, niger, prosterno anterius piceo, capite anterius et ante verticem, prothorace in medio et ad latera elytrisque humeris, fascia submediali maculisque apicalibus testaceis, pedibus pos- terioribus piceis, femoribus nigricantibus, pedibus anterioribus testaceis ; epipleuris latis. Long. 12i, lat. 7| m.m. 682 On Aquatic Caimivorous Coleoptera or Dytiscidce. Fern., nitida elytris in medio ad basin punctis subtilibus impressis. The species is conspicuous by its form, which is very broad behind the middle, as well as by the comparatively abruptly defined post-medial yellow fascia of the elytra : the middle of the prosternum is very broad and thick, and very prominent in fi-ont. I have seen very few individuals, mostly in bad condition. South America, (Cayenne). 969. 1067. Thermonectes cuneatus, n. sp. — Convexiusculus, vix latus, anterius angustatus, Ifevigatus, nitidus, niger, capite anterius et in medio verticis, pro- thorace in medio et ad latera elytrorumque signaturis paucis, pedibusque anteriori- bus testaceis ; elytris plaga elongata humerali, fascia postmediali valde interrupta maculaque subapicali testaceis, epipleuris sat latis. Long. 11l, lat. 6i m.m. Fern., nitida, elytris fere leevigatis, in medio ad basin punctis paucis subtilis- simis. I have seen only a single individual of this species, which a])pears closely allied to D. interruptus, but is considerably smaller, with the medial yellow fascia and subapical mark a good deal diminished, while the humeral mark is more elongate : the posterior portion of the epipleurse is less dilated, and the punctuation on the elytra of the female is exceedingly indistinct. The markings of the upper surface give this species a resemblance to a very large individual of Acilius raargine- guttatus (No. 1070). Panama. 970. 1068. Thermonectes batesi, n. sp. — Convexiusculus, iiaud latus, Isevigatus, nitidissimus, niger, capite anterius et ante verticem, prothorace ad latera et trans- versim in medio, elytris signaturis numerosis irregularibus, antenuis pedibusque anterioribus testaceis ; epipleuris latis ; prosterni in medio minus lato. Long. 11, lat. 61 m.m. Fern., pernitida, elytris ad basin punctis numerosis impressis, prothorace utrinque parum conspicue punctato. The yellow marks on the elytra consist of a small humeral mark, and a very irregular curved series extending from the scutellum to the outer margin below the humeral spot ; beyond the middle a very irregular band, dilated in front about the suture, so as to form there an irregular discoidal pair of marks, and an irreo-u- lar subajjical interrupted fascia. I have seen only a single individual ; it is a female, and has the sexual sculpture on the base of the wing-cases rather dis- tinct, but the punctures less elongate than in the allies. The species will be easily identified amongst the allies, by its much varigated elytra, and the narrower prosternal process and middle part of the prosternum. South America, ( Upper Amazons, Bates). 971. On Aquatic Carnivorous Coleoptera or DytiscidcE. 683 1069. Colymbetes marmoratus, Hope, Ilydaticus marmoratus, M.C. — Convexius- culus, lasvigatus, nitidus, subtus rufus, supra niger, Isete testaceo-variegatus, elytx'is maculis magnis testaceis ; elytris epipleuris haud latis. Long. 13, lat. Ti m.m. Fern., elytris ad basin punctis elongatis numerosis impressis. In the male of this species the three larger palettes on the undersurface of the front feet differ little inter se in size, and are distinctly, but not greatly, larger than the others. The species is a very prettily coloured one and easily distinguished amongst its allies by its colour and markings ; the sides of the thorax are broadly yellow, and across the middle is a yellow band which however does not communicate with the yellow of the side : the side margin of the wing case is yellow till near the apex, at the base on each side of the scutellum is a roundish yellow spot, and between this and the humeral angle an irregularly shaped yellow mark, between, these two basal marks are three small spots arranged in a longitudinal direction, the anterior of them being so small as to be a mere speck ; half way towards the extremity the largest spot exists, it is placed near the suture, and external to it and a little more backward there is another large yellow spot connected with the yellow lateral margin, there are two other spots near the suture behind the large yellow spot, and there are also three other spots, besides the one already mentioned, communicating with the yellow lateral margin ; there are in all eleven spots oa each wing case, without counting the very minute basal speck above described which is very frequently absent. Mexico. 972. 1070. Acilius margineguttatus, Aube, M.C. — Minor, subtus convexiusculus, nitidus, niger, capite anterius et in medio verticis, prothorace ad latera et trans- versim in medio, elytris signatura humerali maculisque duabus ad latera {interdum etiam cum vitta transversa sub-basali, aliaque subapicali), antennis pedibusque anterioribus testaceis ; pedibus posterioribus nigricantibus femoribus ad apicem pallidis ; epipleuris angustulis. Long. 9, lat. 5 m.m. Fern., elytris ad basin lineolis brevibus, plus minusve numerosis, impressis. In the male the three larger palettes of the front tarsi, are well developed, and subequal inter se, in size. The species is a variable one in size, in colour, and the sexual sculpture of the female. The yellow mark across the middle of the thorax is sometimes nearly absent. The yellow mark on the shoulder of the wing case is always present and there is generally a transverse mark proceeding from its hinder pai't towards the scutellum, according to the extent of its development it has the appearance either of a spot or spots, or a nearly entire vitta : there is a yellow spot at the side abotit the middle, and this although variable in size is never largely developed ; there is another spot at the side near the extremity, and this is sometimes developed into a subapical fascia ; near to the suture at the apex TRAKS. nOT. DL'B. SOC, N.S , VOL. U. 4 T 6S4 On Aquatic Carnivorous Coleoptera or Dytiscidce. there is generally a minute fleck : the ventral segments are sometimes marked with yellow. The sculpture on the elytra of the female consists sometimes of some very fine short impressions extending along the middle of the elytra in the longitudinal direction ; at other times the impressions are coarse and deep, occupying the basal portion of the wing-case from the suture to near the outer margin. Very widely distributed in America, from Mexico and the West India Islands to Parana. Group 3. 1071. Dytiscus basilaris, Harr., Acilhis basilaris, M.C. — Minor, parum convexus, nitidus, subtus vel rufus vel piceus, supra niger, capite anterius et in medio verticis, prothorace lateribus fasciaque mediali transversa, elytris lateribus fasciaque sub- basali plus minusve integra, antennis pedibusque anterioribus testaceis ; colore testaceo ad latera et ad apicem elytrorum a lineis et ab irrorationibus nigris disinte- grate ; pedibus posterioribus piceis (vel rufis,) tibiis stepius nigricantibus ; epipleuris angustis. Long. 10, lat. 5 1 m.m. Fern., prothorace elytrisque utrinque punctis elongatis, rudis profundis (plus minusve numerosis) impressis. In the male of this species the large basal palette of the front tarsus is much larger than the two next largest, these indeed are but little larger than the adjacent ones, while the more outward ones are still smaller; the frinmnsr hairs are better developed than in the allies, and are not Interrupted at the point of articulation with the tibia as they are in all the other species. The species is very variable in size and colour, and in the sexual sculpture of the female : but I do not find the characters constant in the series before me so that I am unable to see more than one species in the variations : individuals reddish beneath seem to occur only in California, and the magnitudes of the palettes in the male seems to depart slightly from what exists in individuals from the eastern United States ; I am not able from the series before me however to distinguish more than one species, few of the individuals being in sufficiently good preservation to allow me to form a positive opinion on such points. North America, United States and Mexico, Guatemala. 974. I. 71.— Genus CETHIONECTES. Coxal lines distinct in their hinder portion, supra-articular border broad ; middle femora with only short setae, A single species from tropical Africa. On Aquatic Carnivorous Coleoptera or DytiscidcB. 685 1072. ffithionectes optatus, n. sp. — Latus, anterius angustatus, subtus con- vexus, nitidus, niger, capite antice, vertice maculis duabus, prothorace ad latera, elytris signaturis transversim positis, antennis pedibusque anterioribus testaceis, tibiis tarsisque posterioribus piceacentibus ; elytris epipleuris latis. Long. 12, lat. 7 m.m. Fern., elytris versis basin in medio subtilisslme punctulatis. This species by its broad form, narrowed in front, by its markings and general facias, presents a great resemblance to the South American Dytiscus interruptus (No. 1066) and its allies. The markings of the wing-cases consist of some spots close to the base, forming a transverse band, and some other spots just behind the middle forming another irregular band most distinct near the sides, and an apical yellow mark which is much interrupted with black; the lateral margins also are vaguely yellow. The sexual sculpture of the female elytra is so very slight, that it may very readily pass unnoticed. I have seen only two females, which differ a good deal in the distinctness of the yellow marks on the elytra. The specimen in my own collection was labelled in Mr. Saunders' collection, " W. Afr.", the individual in M. de Bonvouloir's, "Guinee portugaise." Western tropical Africa, (Guinea). 975. I. 72.— Genus SANDBACOTTUS. Coxal lines obliterated, so that no supra-articular border is visible ; middle femora with setee of moderate length. Elytra variegate with large yellow and black marks. Ten species* are known, extending from India through Malasia to Australia. 1073. Sandracottus hunteri, (Crotch,) Hijdaticus fasciatus, M.C. — Ovalis, sat latus et convexus, nitidus, subtus niger, supra testaceus, vertice summo, prothorace anterius et posterius in medio, elytris sutura, fasciis duabus transversis irregularibus punctisque longitudinaliter dispositis nigris, antennis pedibusque anterioribus testaceis, pedibus posterioribus nigricantibus, femoribus ssepe rufescentibus. Long. 122, lat. 8 m.m. In the male the smaller palettes of the front feet are well developed, so that the three larger palettes, which are only of moderate size and differ but little inter se, * Hydaticus baeri, Regt. (No. 1307 hiij. op.), near No. 1073 ; Manilla, should also be referred to tliis genus; whether Colymbetes clairvillei, Mont. (No. 1217), New Caledonia, be a Sandracottus is doubtful. 4 T 3 686 On Aquatic Carnivorous Coleoptera or Dijtiscid I. 75.— Genus ERETES. Thorax with a fine lateral margin. External margin of elytra armed with short spines, at some distance before the apex. Two species are known, one Australian, the other almost cosmopolitan. 1095. Dytiscus sticticus, Linn., Eunectes sticticus, 31. C. — Pallide testaceus, nitidus, vertice nigro-signato, elytris punctis magnis nigris impressis ; elytrorura humeris rotundatis, apice ad suturam acuminato, epipleuris angustissimis ; prosterni processu acuto. Long. 14, lat. 7h m.m. Fern., elytris in latera ad medium depressione plus minusve elongata. Variat, statura plus minusve elongata, thorace in medio elytrisque pone medium plus minusve distincte nigro-fasciatis, his saepius ad latera in medio macula angus- tula nigra. The male differs from the female not only by the dilated anterior tarsi and absence of the lateral impressions on the wing-cases, but also a little in the form of the thorax, which appears less narrowed in front than in the female, and has its sides a little more, and its hind angles a little less rounded. The species besides varying much in size, shows a considerable variation in the black marks of the upper surface ; although these variations are not important, they have, in conjunction with the wide distribution of the species, led to the establishment of a considerable number of false species, for which after a very care- ful examination I find not the least justification. The species is in all its structural characters singularly constant, and with the following one, may be readily distin- guished from all others, by the peculiar serration of the edges of the wing-cases, behind the middle ; this can only be seen with a good lens, and arises from the existence there of a considerable number of extremely short, thick and pointed setfe or spines. The hind tarsi are also very peculiar in this insect, inasmuch as they are punctate externally instead of being polished. Varieties have been described frequently as distinct species. If I am correct in supposing that E. punctipennis, Macleay, is this species, then Australia must be added to the localities mentioned below. Widely distributed in the warm portions of the Old World, apparently rare in America. It is worthy of note that this species is found in a greater number of islands than any other of the Dytiscidse. France, Corsica, Sardinia, Spain, Africa ; Siberia, Japan, Formosa, China, PHlippLaes, Timor, Sumatra, Java, Pulo Penang, Siam, India, Arabia, Mesopotamia ; Canary Islands, Madeira, Cape Verde Islands ; United States of North America, Mexico, Peru ; Guadeloupe, Galapagos. 954. TBANS. EOT. DUB. SOC, K.S., VOL. II. 4 X 700 On Aquatic, Carnivoro^m Coleoptern or Dytiscidce. 1096. Eretes {Ennec(es) australis, Er., M.C. — Testaceus, vcrtice nigi-o-signato, elytris punctis magnis nigris impressis ; elytrorum humeris rotundatis, apice ad suturam acuminate, epipleuris angustissimis ; prosterno processu acuto. Long. 14, lat. 7 m.m. This species is closely allied to Dytisciis sticticus, but is really distinct ; it is generally narrower in proportion, and has a more unicolorous appearance ; the posterior femora and tibiae are more slender ; the punctures of the elytra are even a little coarser than in D. sticticus, but they do not appear so conspicuously black, for the black colour is entirely confined to each puncture, whereas in Dytiscus sticticus, it generally also invades a small area round each puncture ; the thorax is never marked with black ; the female has no trace of the depression at the edge of the wing-cases, and its thorax scarcely differs in form from that of the male. There is generally to be seen a small black dot at the edge of the wing-cases, but it is much smaller than is usual in D. sticticus, and the black subapical fascia is generally entirely absent, but is sometimes faintly indicated. Australia, (Melbourne, Sydney, Paroo liver. Port Denison, Cape York, West Australia). 955. 11. 15. — Group Cybistrini. Swimming legs highly developed and very powerful, their tibiae especially short and broad, and with the lower of their two apical spurs dilated, so that it is much broader than (and frequently longer than) the superior one. The coxal notch of the coxal processes very short, scarcely to be detected from the exterior. Any water-beetle belonging to this group is very readily recognized, the swim- ming legs being different from those of any other of the Dytiscidae, but the species are difficult to distinguish inter se ; the specific chai'acters are found in the size and form, and in the presence or absence of a vellow band along the outside of the wing-case ; this band may be nearly or entirely absent, or it may be present but leave the epipleura and its raised margin of the same dark colour as the rest of the surface, (in this case I speak of it as " vitta intramarginalis," or "vitta lateralis"), or the yellow band may be larger, so that it extends to and includes the epipleura (and in this case I describe it as " margo extemus testaceus "). The sexual cha- racters are also of great importance in distinguishing the species, and the front tarsi of the males should be carefully examined. In order to do this with satisfac- tory results they must be damped and cleansed, and then flattened out so as to place them in their natural position ; when the tarsi have been rendered quite pliable, i he specimens should be placed on a piece of cork covered with clean paper, and the tarsi flattened out and pressed down by means of needles pinned across them in as horizontal a direction as possible, so as to exercise pressure on the foot On Aquatic Carnivorous Coleoptera or DytiscidcB. 701 and keep it flat ; when this has been done the specimen should be left to dry, and the tarsus will afterwards remain extended and flat, so that its dimensions and structure can be readily ascertained. In the measurements I have given of the tarsi, the marginal cilise are not included, the breadth given being that of the joints themselves ; if the marginal cilise are included (when the tarsi have been flattened out) it will be found that the dimen- sions are considerably greater than those I have recorded. The structure of the cedeagus offers very important differences in this genus, and some species are more readily distinguished by examining it than by any other means. Aube and others have attached much importance to the presence or absence of a reddish spot near the extremity of the wing-case ; but this seems to be an eminently variable cha- racter, so that much attention need not be given to it. The group comprises four genera, which may be tabulated as follows : — Anterior border of hind coxa approaching rather closely to the middle coxa. ) S- Three Australian species. J Anterior border of hind coxa rather widely separated from the middle coxa. Coxal lines absent ; nnguicular cleft broad at base. Three Australian and New Zealand species. Coxal lines present ; unguicular cleft narrow and an- gular at the base. Two distinct claws on hind foot in the male sex. Six- teen South American species. Only one claw on hind foot in the male sex. Fifty species ; none from South America. SPENCERIITDRUS. ( Vide below.) IIOMCEODYTES. (Vide p. 703.) MEGABYTES. {Yide^. 704.) CY BISTER. {Yide\>. 714.) I. 76.— Genus SPENCERHYDRUS. Anterior border of hind coxa approaching closely to the middle coxa, terminal portion of wing of metasternum moderately abruptly deflexed. Prosternum deeply canaliculate along the middle. Side of wing-case broadly yellow. Australian species. This genus comprises two very distinct forms : — Prothorax depressed close to the side, so that the margin appears to be 1 raised ; side of wing-case moderately broadly yellow. j Prothorax evenly convex ; side of wing-case very broadly yellow. No. 1097. i Nos. 1098 and 1099. 1097. Spencerhydrus pulchellus, n. sp. — Parvus, oblongo-ovalis, sat convexus, supra olivaceus, capite anterius prothoraceque ad latera testaceis, elytris vitta inarginali lata, sed ad apicem evanescente, testacea ; subtus piceus, pedibus quatuor 4X2 702 On Aquatic Carnivorous Coleoptera or DytiscidoB. anterioribus rufis : prothorace raargine laterali elevato ; prosterno a margine anteriore ad apicem profunde sulcato. Long. 16, lat. 8f m.m. In the male the front tarsi are not large ; their claws are peculiar, very unequal ill length, each has a swelling at the extreme base, and is abruptly bent just beyond this, the front one is elongate and slender, while the hind one is much shorter and is sinuate ; the undersurface is occupied with rather large, nearly cir- cular, palettes, the basal fringing hairs are elongate and well developed, and there is no pubescent area between them and the palettes. The intermediate tarsi are slender, and without sexual pubescence, but their claws are very unequal in length, the outer one being elongate. The female has no sexual sculpture. This interesting little species can be readily distinguished from all its allies by the fact that the thorax is flattened or depressed close to the side so as to give the lateral margin the appearance of being elevated. It varies somewhat in the colour of the upper surface, which is in some cases more tinctured with green and with a metallic lustre than it is in others. Australia, ( S wan River) . 1118. 1098. Spencerhydrus latecinctus, n. sp. — Parvus, oblongo-ovalis, sat convexus, supra piceo-niger, capite anterius prothoraceque ad latera testaceis, elytris latissime testaceo-cinctis ; subtus piceo-rufus, pedibus quatuor anterioribus rufis ; prosterno a margine anteriore ad apicem sulcato. Long. 181, lat. 10 m.m. In the male the front tarsi are moderately large, their claws are greatly and abruptly curved, and the anterior one is nearly twice as long as the other ; the undersurface is furnished with rather large elliptico-circular palettes, and the basal fringing hairs are well developed, there being no pubescent area between these and the palettes. The intermediate tarsi are simple, their claws rather elongate and slightly unequal. The female is unknown to me. This and the following species are readily distinguished from the allies by the very broad lateral yellow band of the wing-cases, even at the apex it is very broad. Australia. 1119. 1099. Spencerhydrus semiflavus, n. .sp. — Parvus, oblongo-ovalis, sat convexus, supra viridi-olivaceus, oinnium latissime testaceo-cinctus ; subtus testaceus ; pro- sterno a margine anteriore ad apicem sulcato. Long. 19, lat. 10 m.m. I have seen only the female of this species ; it has on the thorax near the sides numerous short, rather fine scratches, Although probably closely allied to S. latecinctus, I think this will prove a dis- On Aquatic Carnivorous Coleoptera or DytiscidcB. 703 tinct species, the undersurface being of a pure yellow colour, and the yellow cinc- ture of the upper surface being even broader than in that specis. Australia, (Darling River). 1120. T. 77.— Genus HOMCEODYIES. Coxal lines absent ; unguicular cleft broad and rounded at base. This genus comprises three species* found in Australia and New Zealand. They form two well-marked groups : — Prosternum distinctly cliaunelled along tlie middle, postero-external ) ^ llnO angle of hiiid femur rectangular ; size small (15 ni.m.) long. J Prosteraum indistinctly grooved; postero-extei'nal angle of hind 1 -^j ,,„, , 110'' femur acute or spinose ; size rather large (about 25 m.m. long). j ' 1100. Dytiscus atratus, Fab., Tragus ntratus, M.C. — Minor, ovalis, anterius conspicue angustatus, convexus, supra niger, capite anterius prothoraceque ad latera testaceis ; el\ tris vitta marginal!, posterius attenuata et angustissima, testacea ; subtus nigro-piceus, pedibus quatuor anterioribus testaceis, tarsis intermediis piceis, pedibus posterioribus piceis, crassiusculis ; prosterno sulca angusta anterius dilatata et profunda. Long. 15, lat. 9 m.m. In the male the front tarsi are small, their claws are moderately elongate, and but little unequal, the palettes of the undersurface are small and oblong, the pubescent area moderately large ; on the intermediate tarsi the three basal joints are densely clothed beneath with rather long sexual pubescence, their claws are simple and equal. This little species has a good deal of resemblance to Cybister senegalensis (No. 1145), but is readily distinguished from it by the sulcate prosternum. The few specimens I have seen of the species show little variation, in some of them the uppersurface has a faint metallic lustre. Australia, (Brisbane, Rockhampton, Clarence River, South Australia). 1115. 1101. Cybister scutellaris. Germ., Tj-o^'ms scuieZ^am, M.C. — Ovalis, parum con- vexus, supra olivaceus, capite anterius prothoraceque ad latera testaceis, elytris vitta marginali posterius parum arguta testacea ; subtus testaceus ; pedibus pos- terioribus piceo-testaceis, femoribus angulo posteriori-externo acute subspinoso ; prosterno late obsoletissime sulcato. Long. 26, lat. 14 m.m. * The two folloMdug species should very probably be added to this number: — Cybister goryi, Aubd (No. 1277 huj. op.) near No. 1100; Australia.— Cybister insularis, Hope (No. 1278), near 1100; Tasmania. 704 On Aquatic Carnivorous Coleoptera or Dijtiscidce. In the male the front tarsi are small, their claws nearly equal and rather short, the palettes of the undersurface are small and oblong, and the pubescent area moderately large : on the intermediate tarsi the basal joints are quite bare, but the third one bears a broad patch of rather long very dense hairs, the claws are simple and equal. The female has a dense but rudimentary and obsolete sexual sculpture on the wing-case, consisting of excessively fine, short and dense, irregular or curved scratches, these are most distinct at the base, become obsolete before the apex, and also towards the suture and lateral margin. The species varies somewhat in size, and in the colour of the uppersurface, which shows sometimes a distinct metallic reflection, while sometimes the scutellum is more or less flavescent ; the yellow colour of the undersurface is sometimes somewhat embrowned in parts, this being perhaps due to decomposition : the spine at the outer angle of the hind femora is sometimes more prolonged and distinct than in other cases. The sulcation of the prosternum is peculiar, and seems to be formed by two very obsolete slightly raised lines proceeding from each front angle of the middle portion, and extending backwards about as far as the lower part of the coxae. Australia, Tasmania and New Zealand ; (apparently very abundant and widely distributed Ln Australia). 1116. 1102. Cybister hookeri. White, Tragus liookeri, M.C — Ovalis, sat convexus, supra niger, capite anterius prothoraceque ad latera testaceis, ely tris vitta marginali, posterius angustissima, testacea ; subtus nigro-piceus, pedibus anterioribus testaceis femoribus in medio piceis, pedibus intermediis piceo-testaceis ; femoribus pos- terioribus angulo posteriori-externo acuto, parum producto ; prosterno anguste obsoleteque sulcato. Long. 25, lat. 13 m.m. This species is closely allied to Cybister scutellaris, but is readily distinguished by the colour of the undersurface ; the groove of the prosternum though formed in a similar manner to that of C. scutellaris, differs by the lines which bound it be- coming more approximate, and also by its being continued along the prosternal process. The sexual characters in male and female are almost indentical with those of C. scutellaris. The few specimens I have examined show very little variation. New Zealand. 1117. I. 7%.— Genus MEGABYTES. Coxal lines present ; unguicular cleft narrow and angular at base ; hind tarsi in the male sex terminated by two distinct claws ; (females always with two claws, but the inner one frequently small and rudimentary). On Aquatic Cat'nivorous Cuhoptera or Dytiscidce. 705 The species* are all South American and may be arranged in six groups as follows. 1 • •\ ID u I3 a m U o • ;-i .jg O a -Q so g _a *-*j a cS -s T3 • fH a .9 o 13 +3 c4 -5 3 % u CD ^ >< '^ ^ CI a ^ ^ 'o -g & "S" <*-t c^ ••■' cc -^ O to a fl s O t<

claw shorter and finer than outer one. ) Group 2. (No. 1105.) O Size small (about 23 m.m.); inner claw on hind foot of males as large as the other ; apex of metasternal wing near to epipleura ; with or without lateral yellow band on elytra ; females with a beautiful sexual sculpture. Group 3. (Nos. 1106 to 1109). Size moderate (29 m.m.) ; elytra with yellow stripe; apex ] of metasternal wing near to epipleura; female V without sexual sculpture. j Group 4. (No. 1110). Each sex with two claws of nearly equal length on hind foot; the 1 smaller spur of hind tibia minutely tridentate or trituber- > Group 5. (Nos. 1111 to 1116.) culate at the apex. j Two claws of about equal length on hind tarsus in each sex ; smaller )« e /-kt iii»7 jiiio\ f.,. , ,.,? 1 i" i-f i . i -i > Group 6. (Nos. 1117 and 1118). spur of hmd tibia largely biturcate at extremity. J Group 1. 1103. Megadytes expositus, n. sp. — Ovalis, elongatus, sat convexus, nitidus, supra olivaceus, vage testaceo-cinctus, subtus piceus, pectore prosternoque in mediis olivaceo-metallescentibus ; pedibus quatuor anterioribus rufis, posterioribus piceis trochanteribus dilutioribus ; pectore longitudinal] ter arcuate ; femoribus posteriori- bus angulo externo spinoso-acuto. Long. 32, lat. I62 m.m. The male has the front tarsi small attaining only 2 to 2J m.m. in the transverse direction ; the intermediate tarsi have long sexual hairs on the two basal joints, and a slight tendency to a similar development on the third joint. The females have a very fine and obsolete sexual sculpture on the wing cases, consisting of very fine punctuation and some very short indistinct scratches along the middle towards the base. •Reference should also be made to Cybister seneus, Orm. (No. 1274 luij. op.)! No. 1104 var. ; South America. 706 On Aquatic Carnivorous Coleoptera or 'DjtisciduB. The species varies much in size and minute details, but I can see no signs of specific distinction. It cannot be mistaken for any other. OhUi. 1100. 1104. Cybister glaucus, Brulle, Tragus glaucus, M.C. — Ovalis, subdepresssus, anterius angustatus, nitidus, Isevigatus, supra olivaceus, capite anterius parum argute testaceo, thorace elytrisque lateribus jjIus minusve vage ferrugineo-tinctis ; subtus vel piceus vel nigricans, pedibus quatuor anterioribus rufis, posterioribus vel ferru- gineis vel nigris ; femoribus posterioribus angulo externo minutissime acuto vel recto. Long. 28, lat. 16 m.m. The male front tarsi are small, attaining only 2 m.m. in the transverse direction ; the intermediate tarsi have elongate sexual hairs on the basal joint, and also a few on the extreme base of the following joint. The female appears to be quite with- out sexual developments, but under a powerful lens traces of a rudimentary sexual sculpture may generally be found, consisting of a very fine punctuation, more or less mixed with excessively fine scratches, along the middle of the wing- cases near the base. This species also appears to be a variable one ; there may be roughly said to be two forms, one in which the colour of the upper and under surface and the hind legs are tinctured with ferruginous, and another in which the colour is nearly black with olive reflections ; the former of the two forms generally has the apical angle of the femora more acute, and the females have the sexual sculpture more obsolete than in the other variety ; but these characters are variable and indicate no specific distinction. South America ; especially in the south-east ; Buenos Ayres, Monte Video ; Bolivia {fide Mus. Castle- nau). 1101. Group 2. 1105. Dytiscus latus, Fab., Trogus lotus, M.C. — Ovalis, crassus, sat oonvexus, saepe ad basin eljrtrorum subsulcatus, olivaceus, capite anterius vage ferrugineo ; subtus niger, prosterno in medio olivaceo ; pedibus quatuor anterioribus rufo-obscuris, posterioribus piceis : antennis parum gracilibus. Long, 22, lat. 13 m.m. The male has the front tarsi quite small, attaining only l\ m.m in the transverse direction, their fringing hairs at the heel are short and placed very near the palettes so that there is no pubescent area ; the iutei'iuediate tar.si have a narrow line of quite short sexual pubescence along the underside of the basal joint, and there may be traces of a similar line on the following joint; the inner claw on the hind feet is much smaller and shorter than the outer one. The female has a sexual sculpture On Aquatic Carnivorous Coleoptent or Bi/tisculce. 707 oil the wing-cases, consisting of more or less coarse punctures which are scarcely elono-ated, they vary in the extent of their distribution, sometimes extending along half the length of the elytra, but are always widely separated from the outer margiu, and only approach the suture at the base ; the rudimentary claw^ of the posterior tarsi is not much developed and is only to be seen on the underside of the other claw. The species is a variable one in size and colour, and in form is most inconstant, being sometimes greatly narrowed in front, sometimes not at all ; it possesses a scattered fine punctuation on the wing-cases, whicli also is variable ; the sides of the thorax are often vaguely ferruginous, but never distinctly yellow. It may always be distinguished from the following species by the male front tarsi and hind claws, by the shorter and less slender antennae and by the deflexed lacinite of the hind coxae being nearer to the epipleurse, the female moreover has its sexual sculpture tending to spread less towards the outer margin of the wing-cases. Soutli America, (Buenos Ayres, Monte Video, Uruguay, Entee Rios, Parana). 1102. Group 3. 1106. Dytiscus Isevigatus, 01., Tragus Icevigalus, M.C. — Ovahs, sat latus et con- vexus, supra olivaceo-niger, capite auterius prothoraceque ad latera anguste testa- ceis, elytris versus apicem plus minusve vage ferrugineo-tinctis vel submaculaiis ; subtus nigricans, pedibus quatuor anterioribus rufis, posterioribus piceis; antennis gracilibus. Long. 21i, lat. 12i m.m. The male has the anterior tarsi small, attaining 2 m.m. in the transverse direction, their claws are only moderately elongate, and are therefore not conspicuously unequal in length ; on the undersurface the palettes are rather narrow, the basal fringing hairs are rather fine and moderately short, and at the heel diverge much from the palettes, so that a distinct pubescent area is formed ; the intermediate tarsi are rather slender, and the three basal joints bear beneath an elongate sexual pubescence, and on the fourth joint there is a less conspicuous development of such pubescence. The female has usually a distinct though not extensive sexual sculp- ture on the base of the elytra ; this sculpture consists of elongate punctures, which at the extreme base extend from the scutellum to quite near the lateral margin, they do not extend, however, more than one-third of the way to the apex, diverge greatly from the suture as they proceed, and also to a less extent from the lateral margin. On the hind tarsi of the male the inner claw is quite as long as, or even longer than, the outer one, while in the female this inner claw remains rudimentary, and is only to be perceived by examining the undersurface of the other claw, to which this rudimentary one remains closely applied. This species is variable, but it is possible that some of what I have considered TRANS. ROT. DUB. SOC, N.S , VOL. II. * T 708 On Aquatic Carnivorous Colecptcra or DytiscidcB. varieties may prove to be good species ; the sexual characters of male and female distinguish it amply from the following ones. In Mexico the females appear to be usually nearly or quite destitute of sexual sculpture. South America to Mexico ; Bahia (Castlenau) ; Santa Cruz, 10 to 17, 10, 1872, Van Volxem ; Panama, Cliontales, Mexico. 1103. 1107. Megadytes fraternus, n. sp. — Ovalis, satlatus et convexus, anterius angus- tatus, capite anterius prothoraceque ad latera anguste testaceis, elytris versus apicem obsolete ferrugineo-maculatis, subtus nigricans pedibus quatuor anterioribus rufis, tarsis intermediis picescentibus, pedibus posterioribus nigro-piceis ; antennis gracilioribus. Long. 22j, lat. 13 m.m. The front tarsi of the male are large, attaining nearly 3 m.m. in the transverse direction, their claws are elongate, the front one being conspicuously longer than the other ; on the undersurface the palettes are broad, the basal fringing hairs are stout and elongate, and at the heel diverge distinctly but not greatly from the palettes ; the pubescent area has a great extension in the transverse in comparison with the longitudinal direction. The intermediate tarsi bear elongate sexual pubescence on the three basal joints. The female has the thorax more dull than the male, and the elytra show a highly developed and beautiful sexual sculpture, consisting of very short but regular rectilinear impressions covering the whole surface, except on a quite small space at the apex. This species is variable, or rather perhaps will prove to be one of several closely allied species ; what I have decided to treat as varieties being in that case really distinct species. In Guadeloupe and St. Domingo the sculpture in the females does not reach quite to tbe lateral margin. In Surinam and Demerara a very large variety occurs, with the male tarsi very highly developed. The type above described by me is from Panama ; and in the more southern parts of South America the sexual characters appear to be not quite so highly developed. Panama; Guatemala (Duenas, G. C. Cliampion), Guadeloupe, St. Domingo, Demerara. 1104. 1108. Megadytes steinheili, Wehnoke {rx parte) Stet. Ent. Zeit. xxxvii, p. 359. — Ovalis, latiusculus, anterius minus angustatus, capite anterius prothoraceque ad latera anguste testaceis, elytris versus apicem obsolete ferrugineo-maculatis ; subtus nigricans, pedibus quatuor anterioribus rufis, tarsis intermediis picesentibus, pedibus posterioribus nigro-piceis ; antennis gracilioribus. Long. 23, lat. ISi m.m. This species is very closely allied to M. fraternus, but is bi'oader in front, and the sexual characters are even more highly developed, and the shape of the male tarsi 0?i Aquatic Carnivorous Coleoptera or Dytiscidce. 709 is a little different, owing to the heel being very little prolonged (i.e., the basal fringing hairs diverging but little from the palettes near the articulation with the tibia) they are nearly elliptical in form ; they attain about 3^ m.m. in the transverse direction. In the female the thorax is very dull, and tlie sexual sculp- ture is deep and close, and as in the preceding species covers the greater part of the elytra. Wehncke's description of the female must have been made from another species, as he states the elytra to be free from sexual sculpture. South America (Medellin, Columbia ; Steinheil). 1105. 1109. Megadytes flohri, n. sp. — Ovalis, sat latus et convexus, supra nigricans, capite anterius, prothorace anterius elytrorumque lateribus rufescentibus ; subtus piceus, pedibus rufis, femoribus posterioribus picescentibus ; antennis gracilioribus. Long. 22, lat. 12 m.m. The front tarsi of the male are small, being 2 m.m. in the transverse direction, the basal fringing hairs are rather short and elongate, and at the heel diverge a little but not greatly from the palettes. The intermediate tarsi bear elongate sexual pubescence on their three basal joints. The female has no trace of any sexual sculpture. This species has the male tarsi as small as in Dytiscus Isevigatus (No. 1106) but their structure beneath is more like that of M. fraternus (No. 1107) : from both these allies it departs by the rufescent outer margin of the wing-cases • this red colour extends to and includes the epipleurpe. T have seen only a single pair and they are rather immature. Mexico, (found by Mr. Flohr.) 1126. Group 4. 1110. Cybister puncticollis, Aube, Tragus puncticollis, M.C. — Ovalis, parum latus, nigricans, nitidus, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali versus apicem parum arguta testacea ; pedibus quatuor anterioribus rutis ; pe Jibus posterioribus piceis, femoribus fere nigris, angulo externo tibiisque plaga superior! rufescentibus, calcari superior! simpliciter acuminato ; elytrorum epipleuris sat latis. Long 29, lat. 16 J m.m. I have not seen the male of this species ; the female seems at first sight to be desti- tute of sexual sculpture, but on careful examination there is seen on the basal portion of the elytra a rudimentary sculpture of short irregular scratches, mixed with a very fine punctuation ; on the thorax there is an extremely fine close * T 9 710 On Aquatic Carnirorous Coleoptcru or Dijtiscidce. punctuation near the sides, and there are also a few fine punctures scattered over its surface ; the internal claw of the hind feet remains rudimentary and can only be seen at the base and underside of the larger claw. The only two specimens I have seen of this species, I obtained from Castlenau's collection ; one of them which is rather larger and broader than the other, was standing side by side with a male of another species, labelled " Cy bister fallax, Aube, dubius Lucz. Cayenn." ; the other was standing alone labelled " Cybister puncticollis, Brulle, Bo. Ayres,' while on the pin was a label, " Bresil, C'ol. Dejean " I am not at all sure that this is really Brulle's C. puncticollis which was found on the Kiver San Miguel, centre of Bolivia. South America, (1 Buenos Ayres; ? Cayenne). HOG. Group 5. 1111. Cybister fallax, Aubd, Tragus fallax, M.C. — Ovalis, parumlatus, convexus, nitidu.s, supra olivaceo-niger, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali posterius lata sed parum arguta, testacea ; subtus niger pedibus quatuor anterioribvTS rufis, pedibus posterioribus picescentibus ; elytrorum epipleuris parum latis. Long. 27, lat. 15i m.m. I have not seen any male of this speeies, the female has no trace of any sexual sculpture. The species is readily distinguished from others of this group, by its smaller size and narrower form ; the yellow band on the elytra is broad, at the shoulder it quite touches the lateral margin, aiter that is distinctly sej^arated from it, behind the anterior two-thirds of its length it becomes broader and aarain reaches the margin, though in a somewhat vague manner, just before the extremity it is dilated by joining an agglomeration of small ferruginous dots, and terminates as a point at the suture. I have seen only two individuals of this species, one of them, from Dejeau's collection, was there labelled " Trochalus fallax mihi, h. in Cayenne, D. Lacordaire" : the other w^as in Edwin Brown's collection and labelled in his handwriting " Cybis- ter flavocinctus, Chev., Mexico." The determination being wrong it is probable that the locality also of this latter specimen may be erroneous. Cayenne.; 1 Mexico. 1107. 1112. Megadytes obesus, n. sp. — Ovalis, latus, parum elongatus, convexus, supra olivaceo-niger, capite anterius prothoraceque lateribus testaceis, elytris vitta intra- marginali ante apicem evanescente testacea ; subtus niger, pedibus quatuor On Aquatic Carnivorous Coleoptera or DytiscidcB. 711 anterioribus rufis, tarsis intermediis piceis, pedibus posterioribus nigricantibus ; elytrorum epipleuris versus apicem paruin latioribus. Long. 30, lat. 18 man. In the male the front tarsi are small, attaining about 2^ m.m. in the transverse direction, their claws are rather short ; the middle feet have elongate sexual pubescence on the three basal joints, their claws are of moderate size and simply curved, the inner one being a good deal shorter than the outer. The female I have not seen. The species much resembles Cybister costalis (No. 1116), but is smaller and narrower, and the male anterior tarsi are smaller, and the claws of the intermediate feet much less developed, and the epipleurae of the elytra are much narrower. It is smaller than C. robustus, and has the epipleura; narrower, Panama. 1108. 1113. Cybister robustus, Aubd, Trocjus robustus, M.C. — Ovalis, latus, anterius angustatns, sat convexus, nigi'icans, capite anterius prothoraceque ad latera tes- taceis, elytris vitta intramarginali, ad apicem lata sed parum determinata, testacea ; pedibus quatuor anterioribus rufis, tarsis intermediis piceis ; pedibus posterioribus piceis, tibiis superne rufescentibus, temoribus nigris ; elytrorum epiplemus sat latis. Lonsr. 3.5, lat. 20 m.m. I have seen only one male of this species ; the sexual characters of that sex seem to be the same as in M. obesus, the front tarsi being scarcely 2^ m.m. in the transverse direction. South America. (Buenos Ayres, fide Castlenau). 1109. 1114. Megadytes perplexus, n. sp. — Ovalis, latus, anterius angustatns, convexus, supra olivaceo-niger, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali ad apicem obsoletescente testacea ; subtus niger, pedibus quatuor anterioribus rufis, tarsis intermediis piceis ; pedibus posterioribus piceis, tibiis superne rufescentibus, femoribus nigris ; elytris ad apicem punctis impressis con- spicuis, epipleuris parum latis. Long. 35, lat. 20 m.m. The characters of the male are the same as in Cybister robustus ; the species must indeed be very closely allied to C. robustus, but the only individual before me I cannot reconcile therewith ; it differs somewhat in colour and form, and has the epipleurfe decidedly narrower throughout its whole length. It is perhaps still closer to M. obesus, but is considerably larger : in both these species the impressed punctures on the apex of the elytra are much more conspicuous than in the allied species. The only individual I have seen of this species existed in Edwin Brown's -collection, without any indication of locality. South America ? 1110. 712 On Aquatic Carnivorous Coleoptera or DytiscidcB 1115. Megadytes gravidus, n. sp. — Ovalis, iatus, anterius angustatus, sat con- vexus, supra olivaceo-niger, capite anterius prothoraceque ad latera testaceis, elytris vitta intramargiuali obsoletissima, fere tantum ad basin distinguenda ; subtus niger, pedibus quatuor anterioribus rufis, tarsis intermediis piceis ; pedibus posterioribus piceis, tibiis superue rufescentibas, femoribus nigris ; elytrorum epipleuris sat latis. Long. 33, lat. 19b m.m. I am acquainted only with the female of this species, which shows no trace of any sexual sculpture. The species is probably very closely allied to those preceding, especially to C. robustus, but the very obsolete lateral band of the elytra if constant, wiU render it easily distinguishable. Brazil. (Santa Cruz, Van Volxem). 1111. 1116. Cybister costalis, Aube, Troyus costalis, M. C. -Ovalis, Iatus, supra olivaceo- niger, capite anterius prothoraceque ad latera testaceis, elytris lateribus ante apicem sub-explanatis, vitta intramarginali, posterius lata sed parum determinata, testacea ; subtus niger, epipleuris latioribus, pedibus anterioribus rufis, femoribus in medio nigricantibus, intermediis piceis, femoribus rufescentibus medio nigri- cantibus, posterioribus nigro-piceis, tibiis superne plus minusve rufescentibus. Long. 31, lat. 19 m.m. The male has the front tarsi moderately large attaining 3 m. m. in the transverse direction ; the intermediate feet have the tliree basal joints furnished with elongate sexual pubescence, and their claws elongate and unequal, the outer one being conspicuously thickened, and its under edge nearly straight. The female has a highly developed sexual sculpture, the thorax being entirely covered with deep irregular scratches, and the elytra bearing similar scratches on the greater part of the surface, the sutural portion, however, remains smo.ih except at the base, and the explanate lateral portion is also smooth. In the Stet. Ent. Zeit. 1847, p. 52, will be found a long discussion ou Fabricius' species of this name ; the discussion being based on an examination of the Fabrician types in the collections at Kiel and Copenhagen ; the conclusion arrived at is that Dytiscus costalis, lab., is not Cybister costalis, Aube. Schaum's discussion, however, was imperfect, inasmuch as he seems to have been unaware that the earliest descrijition of Dytiscus costalis is contained in the Systema Entemologiae, p. 230. (1775), not in Ent. Syst. I, p. 187, which dates only from 1792. If reference be made to the earlier description, it \s ill be found that it agrees sufficiently with Aube's Cybister costalis to have justified Aube inciting it. On the other hand, it would be improper to assign the name Dytiscus costalis, Fab., to Cybister dejeani, Aube, as is suggested by Schaum on the authority of the type, for Fabricius says, " habitat Surinami, D. Yeats," while C. dejeani is found only in the East Indies. On Aquatic Carnivorous Coleoplem or DytiscidcB. 713 The simple course seems to be to use the name Cybister costalis, Aube, for Aube's species ; this does not prevent those who are fond of archaeological nomenclature citing "? Dytiscus costalis, Fab.," in addition if they desire so to do. South America, (Cayenne, Guyana, Demerara) {? Antilles ? United States of North America). 1112. Group 6. 1117. Cybister giganteus. Cast., Tragus giganteus, M.C. — Major, ovalis, sat convexus, nitidus, nigricans, capite anterius prothoraceque lateribus testaceis, elytris vitta intramarginali posterius obsoletescente testacea ; pedibus quatuor anterioribus piceo-rufis. femoribus versus basin magis nigricantibus ; posterioribus fere nigris Long. 41, lat. 23 m.m. In the male the anterior tarsi are small, (for the size of the species) attaining from 2| to 3 m.m. in the transverse direction, their claws are short ; beneath the palettes are narrow, the pubescent area is large, and the basal fringing hairs are very little developed ; on the middle feet there is a narrow line of sexual pubescence on the under side of the basal joint, and the claws are short. The female has no trace of sexual sculpture. This species varies much in size and form, and also in the width of the marginal yellow band on the elytra, as well in the distinctness of its development near its termination. I have not been able to find any means of distinguishing the variations with certainty, and cannot point out any character for separating Aube's C. L'herminieri from C. oriaranteus. The smallest individual I have seen measures 36 m.m. by 20 m.m., the largest 41 m.m., by 23l m.m. I have examined the cedeagus, in all the males I have seen, and find slight variations in its form, but no difference of importance in this respect between the Brazilian C. giganteus and the C. L'herminieri from Guadeloupe. This organ in this species remains largely in a membranous condition, and does not exhibit the fine and perfect structure seen in D. limbatus (No. 1157), and its allies. Two individuals from Brazil, however, show so much difference in the form of the lower portion of the cedeagus as to render it probable they will form a distinct species ; but as I can see no other character to distinguish them from certain varieties of C. giganteus, I do not think it proper to attempt to dift'erentiate the species at present. Brazil, Central America, Mexico, Guadeloupe, Antigua, Cuba. 1113. 1118. Megadytes ducalis, n. sp. — Maximus, ovalis, convexus, nitidus, niger, €apite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali ante apicem evanescente testacea, pedibus quatuor anterioribus piceo-rufis, femoribus versus basin nigricantibus, pedibus posterioribus nigris. Long. 471 m.m., lat. 265 m.m., alt. 15§ m.m. 714 On Aquatic Carnivorous Coleoptera or Dijtiscidw. The front tarsi of the male are rather small for the size of the insect, being about OS m.m. in the transverse direction ; beneath the palettes are narrow, the pubescent area large, and the basal fringing hairs fine and but little developed. On the middle tarsi the basal joint bears beneath a very large patch of elongate, dense sexual hairs, they cover the whole of the joint and greatly overlap the following one. I have seen only a single individual of this species. It is the giant of the Dytiscidae, much exceeding in bulk the largest individuals of Cybister giganteus. It is closely allied to that species but is distinguished by its larger size, and the male is also conspicuous by the great development of the sexual pubescence on the basal joint of the intermediate foot. The swimming legs are very powerful, their femora measuring b\ m.m. across. Brazil, (coll. Saunders). 1114. I. 79.— Genus CYBISTER. Coxal lines present ; unguicular cleft narrow and angular at base ; only a single claw on the hind tarsus in the male sex; (the females also have only a single claw but in some cases a very rudimentary second claw exists). The numerous species* are widely distributed, but do not occur in South America. They may be arranged in six groups as follows : — £-3 o .S TJ " o 2 o -a © -a "i !=> . a ° s o *-^ -* ■*^ ^ M ^ \ Elytra with yellow latei-al stripe ; male with axillar ^ -t^ "3 "^ I rugse. (North American species.) } g .s g 3 . I Elj-tra without yellow lateral stripe ; male without 1 ^ = S g 3 [ axillar ruga;. (Asiatic and African species.) j • • •( 2§5 O «n 5 axillar ruga;. (Asiatic and African species.) El3rtra without yellow lateral stripe, . ^ ^ a © rt ^ "c5 - & . a ^ ^ 03 Elji;ra with yellow lateral stripe extending to and ( including the epipleura. | Elytra with yellow lateral stripe, wliich does not ) extend to or include the epipleura. J The feiaale as well a-s the male furnished ^vith swimming hairs on each side I of the hind tarsi. \ Group 1. Nos. 1119 to 1121. Group 2. Nos. 1122 to 1134. Group 3. Nos. 1135 to 1139. Grouj) 4. Nos. 1140 to 1151. Group 5. Nos. 1152 to 1168. Group 6. Nos?. 1169 to 1171. * The descriptions cited in the following list refer probably in part to species unknown to me : — Cybister auritus, Gei-st. (No. 1275, huj. op.) ? = No. 1280 ; Africa. — Cybister dejeani, Aube (No. 1276) j India. — Cybister jordanLs, Reiche, (No. 1279) ? No. 1169 var.; Syria. — Cybister marginicollis. Boh. (No. 1280), near No. 1129; Caffraria. — Cybister olivieri. Crotch. (No. 1281); North America. — Cybister vuhieratus, Klug. (No. 1283) ] No. 1 133 var. ; Arabia. — Dytiscus extenuans, Walk. (No. 1289) ; Ceylon. — Dytiscus tataricus, Gebl. (No. 1295) ?=No. 1169; Tartary. — Trochalus rugulosus, Eedt. (No. 1509) ] near No. 1167 ; India.— Trogus natalensis, Wehncke (No. 1510) 1 near No. 1148 ; Natal — The systematic position of the following is not quite clear : — Cybister prostevno-\iridis, Orm. (No. 1 282) ; ? South America. On Aquatic Carjiivorous Coleoptera or Dytiscidce 715 Group 1. 1119. Dytiscus fimbriolatus, Say, TiogusJimbnoIatus,M.C.— Oya.\is, supra niger, subolivaceus, caplte anterius prothoraceque lateribus testaceis, elytris vitta lateral! posterius obsoletescente testacea ; corpore subtus piceo, abdominis lateribus flavo- maculatis, antennis pedibusque anterioribus rufis, pedibus posterioribus tarsisque intermediis piceis. Long. 28^, lat. 16 m.m. The male has a narrow excessively obscure band of extremely short sexual pubescence, on the undersurface of the basal joint of the intermediate tarsus ; and the hind coxa has at the apex just iu front of the articulation three or four coarse plicae. The female is without these folds ; but has a well marked sexual sculpture on the upper surface, there are always some fine scratches on each side of the back of the head, and the thorax has numerous irregular scratches, while the elytra are generally covered with longitudinal scratches, anastomosing here and there, and leaving only a small space at the apex, and a band along the suture smooth : the epipleurae, just behind the shoulder, are broader than in the male, and are flattened, and obliquely perpendicular, instead of being rounded, and transverse in direction, as they are in the male. The species appears to be very variable, and it is quite possible that there will prove to be more than one distinct form mixed under its name ; the yellow band on the side of the elytra is rather narrow, and at the apex is indefinite, indeed on the hinder half of the wing-case a line of darker colour separates the yellow line from occupying the outer margin, this darker band is not often very definite ; at the apex at a distance from the suture there are some yellow maculae, which when more than usually distinct give to the yellow marginal band the appearance of being dilated there. In a variety from Texas, the lateral band of the elytra is broader, and reaches in a definite manner to the suture, where however it is thinned out to a point. The sexual sculpture of the female also varies much ; the scratches on the head are always present, and sometimes the scratches on the thorax and elytra are coarse and close, while in certain individuals they become finer, shorter and more isolated, and at the same time occupy a less area on the wing-cases, their disappearance being from the apical and sutural portions. The supplementary obsolete claw of the female hind tarsi also varies in its development, being sometimes so small as to be not very easily detected, while in other cases it is longer, more detached, and more conspicuous, it appears to be most largely deve- loped in those cases where the terminal joint of the tarsus is shortest and thickest. Besides these points of variation, considerable difference is also found in size and colour, and even in the extent of the development of the sexual pubescence on the intermediate tarsi of the male, the band^on the basal joint being sometimes larger, TBAKI, HOT. DOB. SOC, M.S., VOL. U. * Z 716 On Aquatic Carnivorous Coleoptera or Dytiscida. aud when this is the case the following joint or two also show the rudiments of similar pubescent bands. North America, and Mexico; (Pennsylvania, Louisiana, Kansas, Georgia, sec. Crotch). 1050. 1120. Cybister ellipticus, Lee, Tragus ellipticus, M.C. — Oblongo-ovalis, parum latus, supra viridi-olivaceus, capite anterius prothoraceque lateribus testaceis, ely tris margine laterali testaceo lato, vix ad apicem attenuato ; corpore subtus rufo-piceo, antennis pedibusque anterioribus testaceis. Long. 28, lat. 142 m.m. This species seems very closely allied to Dytiscus fimbriolatus, and shows in each of its sexes almost the same sexual characters as does that species ; it is however of narrower and more parallel form, and is different in colour, the undersurface being more dilute, and the upper surface green, while the yellow band on the elytra is very broad and distinct, and is continued at the apex to the suture ; at about the middle of the wing-case the breadth of the yellow vitta is 2f m.m. being just about one-half of the width of the green ground colour. North America, (California). 1051, 1121. Cybister flavocinctus, Aub4 Tragus fiavocinctus, AI.C. — Ovalis, sat latus, posterius parum dilatatus, supra olivaceo-niger, capite anterius prothoracisque lateribus testaceis, elytris vitta laterali etiam versus apicem argute determinata testacea ; corpore subtus piceo, abdominis lateribus flavo-maculatis, antennis pedibus- que anterioribus rufis, tarsis intermediis pedibusque posterioribus piceis. Long. 29 m.m., lat. 15 m.m. This species is excessively close to some of the varieties of Dytiscus fimbriolatus (No. 1119) ; the form however is more parallel in outline, and the yellow band of the sides of the elytra is more definite and distinct in its terminal portion, at the apex it reaches nearly or quite to the suture being however thinned out to a point at its termination. The male characters seem to be almost the same as in Dytiscus fimbriolatus, but the sexual distinctions in the female are less, the head behind the eyes and the sides of the thorax bear fine scratches, but the elytra appear quite smooth, on careful examination however there are found a few very fine short scratches placed on the basal portion of the yellow lateral band ; the sexual flatten- ing and obliquity of the epipleurae is also less than in Dytiscus fimbriolatus. Mexico, (Corafalce, Madame SaUe) ; Texas (coll. Castlenau sub nom. 0. pilati, Dup.) 1052. On Aquatic Carnivorous Coleoptera or Dytiscidce. 71 7 Group 2. 1122. Cybister sugillatus, Er., Trogus bisi^natus, M.C — Ovalis, parum latus, supra olivaceo-niger, prothoracis lateribus plus minusve obsolete rufescentibus, subtus niger, pedibus nigris, plus minusve rufo-variis, tibiis posterioribus superne versus geniculam plus minusve rufescentibus ; antennis rufis, extrorsum fuscescentibus. Long. 22, lat. 12 m.m. Ill the male of this species the front tarsi are comparatively small, and the pub- escent area on the undersurface of the basal joint is quite small ; the longitudinal band of sexual pubescence on the undersurface of the basal joint of the middle tarsi is so little developed that it easily escapes detection, and consists only of a few short pale setae. The female has no sexual sculpture ; the obsolete supplementary claw of its hind foot is easily detected. The species varies a good deal in size and in other respects ; it is sometimes peculiarly dull and its upper surface has then a greasy appearance, at other times it is comparatively shining, and may even have a faint metallic tinge. The reddish colour at the sides of the thorax can be sometimes scarcely perceived while at other times it is very distinct ; there is often a dark red spot near the extremity of each wing case, but sometimes it is quite absent : the colour of the legs also varies a little : the intermediate and anterior femora are nearly black, but are reddish towards their apex, and their trochanters are also red : there is a more or less obscure red- dish spot on each side of the basal abdominal segments. Cybister notasicus, A ube, and C. olivaceus, Boh., are pretty certainly merely synonyms of this species, which is usually known in collections under the name of C. bisignatus, Aub^. China, Thibet, India, Malacca, Philippine Islands, Sumatra. 1053. 1123. Cybister (Trogus) nigripes, Wehncke, Stet. Ent. Zeit. XXXVII, p. 358. — Ovalis, sat latus, parum convexus, niger, elytris posterius subtiliter transversim corrugatis, epipleuris posterius sat latis et planatis. Long. 21, lat. 12 m.m. I have seen but a single individual of this species, and it is in such very bad condition that I cannot exactly determine its characters ; it differs from C. sugillatus, by its much broader form, by the corrugate elytra and broader epipleurse ; from C. siamensis it differs by its much smaller size and shorter form : it has probably the same sexual characters as the two species alluded to, and it is probable that the black colour of the legs is due to this being dyed by the complete rotting of the interior of the specimen. Borneo. 1069. 1124. Cybister siamensis, n. sp. — Ovalis, latus, anterius angustatus, niger, pedibus anterior) bus et intermediis rufo-variis, antennis rufis extrorsum fuscescenti- •1 Z 2 718 On Aquatic Carrdvorous Coleoptera or DytiscidcB. bus, elytris subtillter transversim corrugatis, tuberculisque omnium minutissimis elevatis. Long. 25, lat, 14 m.m. This species is very closely allied to C. sugillatus, but is much larger and broader, and has the surface of the elytra more rugose, and the epipleuras in their posterior portion broader and flatter. The sexual characters are quite the same, the male tarsi being proportionately as small as in C. sugillatus. Siam, (Bangkok and Cliantaboun), Andaman Islands. 1054. 1125. Cybister prolixus, n. sp. — Ovalis, elongatus, angustulus, supra olivaceo- niger, subtus niger, pedibus anterioribus et intermediis rufo-variis, antennis rufis. Long. 24, lat. 12 m.m. This species of which I have seen only a single individual is extremely closely allied to C. sugillatus, but is more elongate, and has the male front tarsi larger, the breadth of their third joint being about 2 m.m., while in C. sugillatus it is only about H m.m. Ceylon. 1055. 1126. Cybister convexus, n. sp. — Ovalis, sat latus, anterius parum angustatus, convexus, supra olivaceo-niger, marginibus magis viridibus, subtus niger, antennis rufis extrorsum fuscescentibus. Long. 29, lat. 16 m.m. This species is much larger than Cybister sugillatus, and of a different form, being less narrowed in front, and so more regularly elliptical ; the front and middle legs seem to be more nearly black in colour. The male front tarsi are slightly more developed than in C sugillatus, and have the pubescent area at the base of the undersurface distinctly larger ; the intermediate tarsi are wanting in the only individual I have seen. It also a good deal resembles the African C. binotatus (No. 1133), and is about the same size as the largest individuals thereof, but is much more convex in form, and the male anterior tarsi are much smaller ; it is probable that the species will prove intermediate between the Asiatic Cybister sugillatus with its allies, and the African C. binotatus. East India. 1056. 1127. Cybister posticus, Aube, Tro^TMs posticus, M. C. — Ovalis, latus, anterius conspicue angustatus, supra parum convexus, nigro-olivaceus, pedibus anterioribus et intermediis nigricantibus rufo-variis ; antennis rufis. Long. 30, lat. 16 m.m. I have seen of this species only a single individual ; it is the male from Dejean's collection which served Aube for his description. It is closely allied to C. sugillatus but is much larger and broader, the male front tarsi are larger, the pubescent area at their base beneath being moderately large ; the line of sexual On Aquatic Carnivorous Coleoptera or Dytiscidce. 719 pubescence on the basal joint of the intermediate tarsi is also less obsolete. From C. siamensis, it differs by its smoother surface, and by the larger male tarsi ; while from C. convexus, it differs by its comparatively broader form which is more narrowed in front, and by its upper surface being less convex in the transverse direction, and by the male tarsi being rather larger. East India. 1057. 1128. Cy bister brevis, Aub^, Tragus hrevis, M.C. — Ovalis, latus, anterius angus- tatus, supra olivaceo-niger, clypeo anterius vage irregulariter testaceo, subtus niger, antennis rufis extrorsum fuscescentibus, pedibus nigris rufo-variis ; capita crebre et fortiter, thorace sparsim subtilius, punctato. Long. 22, lat. 12i m.m. The front tarsi of the male are rather small, and the band of sexual pubescence on the basal joint of the intermediate tarsus is only very slightly developed; the female shows no peculiar sexual sculpture. The peculiar punctuation of the head renders this species unmistakable ; except for that character it is allied to C. siamensis, but it is smaller, has the elytra smoother, and their epipleurae not so broad and flat in their posterior portion. The yellow mark on the front of the clypeus consists of an angular mark on each side, the two being connected together by a very short middle portion. Japan. 1058. 1129. Cybister filicornis, n. sp. — Parvus, ovalis, latiusculus, anterius fortiter angustatus, supra parum convexus, niger, clypeo anterius prothoracisque lateribus testaceis, pedibus anterioribus et intermediis rufis, femoribus basin versus fuscis ; pedibus posterioribus piceis ; antennis rufis, extrorsum fuscis, elytrorum epipleuris versus apicem latis, et planatis. Long. 172, lat. 10 m.m. The anterior tarsi of the male are small, and the basal joint shows beneath a shining space instead of the usual pubescent area ; the basal joint of the intermediate tarsus shows beneath a linear band of short sexual pubescence, and there is a very alight development of similar pubescence at the extreme base of the second joint : the female has no sexual sculpture. This peculiar little species bears a great resemblance to small specimens of the American Dytiscus Itevigatus (No. 1106), but the male has only one claw on the hind tarsus, and the female has no trace of sexual sculpture : it cannot be mistaken for any other. According to the few specimens before me it varies somewhat in size and colour ; a variety from Portuguese Guinea, is smaller than the specimens from the Gaboon, has the upper surface more olivaceous, and the yellow band on the sides of the thorax broader. 7:20 On Aquatic Carnivorous Coleoptera or Dijtiscidce. I expect from Boheman's description of Cybister marginicollis (Ins. Caff. I. p. 235) that it is an insect allied to this species, possibly actually this species, although some of the details he mentions seem scarcely applicable. West Africa, (Gaboon, Isubu, Portuguese Guinea). 1059. 1130. Cybister irritans, Dohrn, Stet. Ent. Zeit. XXXVI, p. 290.— Ovalis, sat latus, anterius augustatus, niger, antennis pedibusque anterioribus et intermediis rufis, his femoribus late nigricantibus, pedibus posterioribus piceis ; epipleuris elytrorum ultra medium latis et planatis. Long. 20i, lat. 12 m.m. In the male of this species the anterior tarsi are leather small, and the pubescent area of the basal joint is but slightly developed ; the basal joint of the intermediate tarsus bears beneath a patch of long hairs, the patch being in form an elongate narrow triangle, and the second joint has also a large development of similar hairs ; the female has no sexual sculpture. Western tropical Africa, (Guinea, ^lonrovia). 1060. 1131. Cj'^bister deplanatus, n. sp. — Ovalis, latus, anterius angustatus, supra parum convexus, olivaceo-niger, pedibus anterioribus et intermediis nigris, rufo- variis, posterioribus piceis, antennis rufis ; epipleuris elytrorum ulti'a medium latis et planatis. Long. 24, lat. 131 m.m. This species differs from C. irritans, by its larger size and broader form, and by the rather greater development of the male anterior tarsi, the dilated joints of which have a greater development in the transverse direction. Western tropical Africa, (Oameroons, Cape Coast Castle). 1061. 1132. Cybister operosus (Dej.) n. sp. — Ovalis; latus, sat convexus, supra olivaceo- niger, nitidus, pedibus anterioribus et intermediis nigris, rufo-variis, posteriori- bus nigris, antennis rufis ; epipleuris elytrorum ultra medium latis et planatis. Long. 31, lat. ITo m.m. This species difters from C. deplanatus, by its larger size, and the greater develop- ment of the male front tarsi ; these are moderately large, and have a distinct though not larare basal area of pubescence beneath : the middle tarsi have a rather large, moderately broad patch of long sexual hairs on the basal joint, and a smaller patch on the following joint. The female has no sexual sculpture. The fine scattered punctures which are seen on the upper surface of the two pre- ceding species are scarcely to be detected in the present one. Madagascar. 1062. On Aquatic Carnivorous Coleoptera or Dytiscidce. 721 1133. Cybister binotatus, Klug, Tragus hinotntus M.C. — Ovalis, parum latus, convexus, supra olivaceo-niger, prothoracis lateribus plus minusve obsolete rufes- centibus, elytris versus apicem ssepius rufo-notatis, subtus niger, pedibus nigricanti- bus, anterioribus et intermediis plus minusve rufo-variis, antennis rufis, extrorsum parum fuscescentibus : epipleuris angustis. Loug. 28, lac. 15 m.m. The male in this species has the front tarsi rather large in the transverse direction, but the pubescent area beneath remains small ; the intermediate tarsi have on the basal joint a rather large patch of rather short hair, this patch has the form of a narrow triangle ; there may sometimes be a very slight development of sexual liairs also on the following joint. The female has always some sexual sculpture on the elytra, though sometimes it is excessively scanty, while sometimes there is even a highly developed sculpture on the thorax, and in the most extreme cases also on the head. The species is a very variable one, and four forms may be distinguished as regards the female sex, although the corresponding males can scarcely or not at all be sepa- rated from one another. First there is the African form ; the female of this has some short, isolated scratches on the middle of the elytra in their basal portion, these are variable in their number and extent, and in the most advanced cases they extend from the scutellum to the shoulder and one half of the length of the elytra, the sutural portion of the elytra remaining smooth however through nearly its whole lensfth ; in these extreme cases there are even a few fine scratches on the basal portion of the thorax. The second form of the female is found in Madagascar, and is the Cybister madagascariensis of Aube ; in this the sexual sculpture is usually greater, and extends more on the anterior part of the insect, the scratches on the elytra are in the least sculptured specimens very few, but they are then placed more on the basal and humeral portion of the elytra, than in the corresponding slightly sculptured individuals of the first form, and there are always fine scratches on the sides of the thorax and one or two behind the eye ; in the most advanced cases of this Madagascar form, the scratches become a good deal deeper and more numerous, and extend over a similar area to what they do in the first form, the thorax becomes nearly covered with short scratches, and those about the eyes though always fine, are more numerous. The third form of the female is that found in Mauritius, (Cyl>ister desjardinsii, Aube), the sexual sculpture seems to be here always (to judge from the few in- dividuals I have seen) highly developed, and extends over two-thirds or three-fourths of the whole area, the sutural portion being much less free from scratches than in the first two forms : the thoracic sculpture is highly developed and beautiful, and quite covers the surface ; on the head there are scratches all along the occiput, and even the central area of the head bears fine scratches. The fourth form of the female is that found in Arabia ; the sculpture of the wing 722 On Aquatic Carnivorous Coleoptera or Dytiscidce. cases is more definitely limited in its area than in the preceding form, the sutural portion being quite smooth except on the basal one-fourth or one-fifth, and there is also a much larger apical portion free from sculpture ; the thoracic sculpture is the same as in the Mauritian form, but that on the head is but slight, there being only some scratches in the neighbourhood of the eyes. In this therefore the chief difierence from, the Mauritian form is that the sculpture is more concentrated on the middle portions of the body : it is possible that this is the insect Klug described as Cybister vulneratus. The males of these forms can scarcely be distinguished inter se. The Madagascar individuals are usually rather broader than the African ones, while the Mauritian examples are rather broader and shorter, and the Arabian individuals are rather narrower, and approach nearer to a truly elliptical form than do any of the others. The species varies a good deal in size and colour, independently of the local variations, and the size of the patch of sexual hairs on the male middle tarsus like- wise varies somewhat : as does also the supplementary obsolete claw of the female hind tarsus ; I have indeed an individual of this sex from Lake Nyassa in which no trace of this claw can be detected. The species is widely distributed in Africa; in the North it reaches to the coasts of the South of Europe, but is there very rare, while in the South it extends to Lake Nyassa ; it is also found in IMadagascar, Mauritius, and Ai-abia (Hedjaz, Dr. 0. Millingen). 1063. 1134. Cybister insignis, n. sp. — Ovalis, anterius angustatus, nigricans, prothorace ad latera vage ferrugineo, pedlbus anterioribus et intermediis, (antennisque ?) rufis ; pedibus posterioribus piceis, tarsis fere nigris. 3Ias, Long. 26, lat. 13i- m.m. Fern., Long. 26, lat. 12 m.m. The male of this species has the front tarsi large, attaining 3 m.m. in the trans- verse direction ; the intermediate tarsi, have on the basal joint beneath, a very large and broad patch of short sexual pubescence, and there is also a large patch on the follow- ing joint, the claws are elongate and nearly straight, the anterior one being thick, and but little longer than the other. The female has the occiput, the thorax and the elytra covered with deep, coarse scratches ; the sculpture on the elytra consists of deep coarse elongate scratches which extend about four-fifths of the length of the elytra, but are represented near the suture by onlj' a few scratches, near the lateral margin there is a land of plica or fold, and the sculpture is abruptly termi- nated at this fold, so that within the lateral margin there appears to be, as it were, a smooth groove, which commences in an indefinite manner a little behind the shoulder, gets broader as it goes backwards, and extends as far backward.s as the scratches do ; the epipleurse of the elytra are broad, flattened and obliquely perpen- dicular a little distance behind the shoulder, and the supplementary claw of the On Aquatic Carnivorous Coleoptera or DytiscidcB. 723 hind tarsus is largely developed in comparison with the allied species. The male is considerably broader than the female, and has the sides of the thorax a little explanate. Although this species resembles superficially in each sex the Mauritian variety of the preceding species, it is perfectly distinct therefrom ; the male has the sexual pubescence of the intermediate tarsi and their claws quite different ; and the sculp- ture of the female though superficially similar is really quite different. I have seen onlj^ a single pair of this remarkable species, the male in the collection of the Genoa Museum, the female in my own. I purchased my specimen from a dealer some years ago, and the Genoa Museum specimen was obtained from the same source ; although both specimens are labelled as being from the Gaboon, I suspect an eri'or of locality, and believe they may be from Madagascar ; the two individuals are old worn specimens and have been pinned two or three times, this of itself makes an error probable ; while the sexual characters are approached only by the Madao^ascar C. owas. Africa, (Gaboon). 1064. Group 3. 1135. Cybister owas. Lap., Tragus owas, M.C. — Grandis, ovalis, latus, convexus, supra olivaceo-niger, subtus niger ; pedibus nigris, femoribus anterioribus et inter- mediis basi apiceque, et tibiis anterioribus plus minusve rufescentibus. Long. 36—40 m.m., lat. 20—22 m.m. The male of this species has the front tarsi very large and highly developed, and attaining as great a length as 4| m.m. in the transverse direction, the fringing hairs even at the base are highly developed and regular, and the pubescent area is large ; on the intermediate feet the basal joint bears a large elliptical patch of very dense short sexual pubescence, and there may occasionally be a very minute patch of similar pubescence on the following joint, the claws are rather elongate and but little curved, the anterior one being a little longer and much thicker than the other. The female has a highly developed sexual sculpture, the occiput being covered with scratches, which on each side near the eye extend much forward, the thorax is also very much sculptured with scratches, these however become scanty or wanting on the middle, the elytra on their basal portion bear deep elongate scratches, which however scarcely, or very slightly only, anastomose here and there ; at the base these scratches reach from the scutellum to the shoulder, they extend rather more than half way of the length of the wing-case, and almost immediately behind the scutellum they begin to diverge from the suture, so that they cover in fact a TRANS. ROY. DUB. SOC, N.S., TOL. II. t A. 724 On Aquatic Carnivorous Coleoptera or Dytiscidce. large almost triangular area, they do not quite reach to the lateral margin but leave a narrow elongate space there smooth : the epipleurse behind ihe shoulders are broad and flattened and obliquely perpendicular. The species varies a good deal in size and somewhat in the colour of the legs, and often the epipleurte and metathoracic episterna are more or less rufescent : and occasionally there may be seen in the male as well as in the female, the rudiments of a second claw on the hind tarsus ; this claw is of short broad triangular form, and is placed at the extremity of the inner terminal point of the unguicular cleft ; in the female of C. binotatus this rudimentary claw appears as a slender elongate process placed along the inner margin of the unguicular cleft. Aube has described as occurring in Senegal a species closely allied to C. owas, and has called it C. bimaculatus; the characters he gives to distinguish the two are quite without importance. I have a female specimen from Doue's collection, said to be from Algeria, and this differs in no respect from large elongate individuals found in Madagascar. I have also a male individual from Lake Nyassa, which is of decidedly more elongate form than any specimen I have seen from Madagascar, and the patch of sexual pubescence on the intermediate tarsus is only one-half the width of what it is in the Madagascar examples. I consider it, however, only a variety of C. owas. In the Munich Catalogue, Harold has proposed the name of Trogus caffer for the Cybister binotatus of Boh. (nee. Klug), but it is doubtful whether Boheman's de- scription indicates more than a female variety of this species. Madagascar. 1065. 1136. Cybister immarginatus, Aube. — Gravidus, ovalis, latus, convexus, supra nio-ro-olivaceus, prothoracis lateribus omnino vage et obsolete rufescentibus, subtus niger, pedibus anterioribus et intermediis jjiceis femoribus basi apiceque, tibiisque anterioribus scepius dilutioribus, pedibus posterioribus nigricantibus ; antennis rufis. Long. 37, lat. 21 m.m. The male of this species has the front tarsi rather small, attaining only 2t — 3 m.m. in the transverse direction, the pubescent area is correspondingly small, and the basal fringing hairs are short so as to project but little beyond the basal pubescence. The intermediate tarsi have a rather large patch of moderately short pubescence, the patch is narrowly oval in form, its basal termination being particularly narrow ; their claws differ but little from those of the female. The female has no trace of any sexual sculpture, and there is never the least rudiment of a supplementary claw to the hind tarsi. The species varies a good deal in size and in colour, it is sometimes nearly entirely black; at other times the metathoracic episterna are very rufescent, and other parts of the undersurface also become more or less rufescent ; the largest specimens attain the On Aquatic Carnivorous Coleoptera or Dijtiscida. 725 size of C owas, but the males of the two species may always be very easily distinguished by the difference in the tarsi, and the females by the want of sculpture and the simple epipleurse. Dytiscus immarginatus, Fab. — This name first appeared in Ent. Syst. App. p. 444, (1794), that in the Syst. El., quoted in Munich Catalogue, being several years subsequent. The description appears to me to point to Cybister binotatus, rather than to this species, to which it has been assigned by Aube and subsequent authors. I am not aware that any Fabrician authentic example exists to settle this point ; and in Dejean's collection the name of immarginatus was assigned to the species for which Aube quoted Fabricius. It will be desirable therefore, it appears to me, to cite Aub^ as the authority for the name of the species, and to add to the synonyms "? Dytiscus immarginatus. Fab. Ent. Syst. App. p. 444." TroiJical Africa, (Senegal, Gambia), Caffraria, (Madagascar ]). lOOG. 1137. Cybister modestus, n. sp. — Ovalis, sat latus, parum convexus, supra olivaceus, prothoracis lateribus vage ferrugineis, subtus nigro-piceus, pedibus anterioribus et intermediis piceis, rufo-variis, pedibus posterioribus nigricantibus, antennis rufis ; elytrorum epipleuris versus apicem sat latis, planatis. Long. 33, lat. 18 m.m. In the mole of this species the front tarsi are only moderately developed, attaining about 2\ m.m. in the transverse direction, and are very similar to those of C. immarginatus, as are also the intermediate feet. The female too is quite without sexual sculpture. The species is closely allied both to C. immarginatus and C. operosus ; it differs from C. immarginatus by its less convex form and smaller size, and by the fact that the epipleuras in their posterior portion are distinctly a little broader and flatter ; from C. operosus it differs by a more elongate and less convex form, by its showing on the upper surface less tendency towards explanation of the sides of the elytra near their posterior part, by the male front tarsi being rather larger, and the sexual hairs of the middle feet shorter, and by the entire absence of any rudiment of a supplementary claw on the female hind tarsus. West Africa, (Cameroons, Isubu, Gaboon.) 1067. 1138. Cybister distinctus, Regt., Ann. Soc. Fr. V, VII, p. clvii. — Robustus, ovalis, sat latus, convexus, supra olivaceus, subtus niger, pedibus anterioribus et intermediis femoribus basi apiceque tibiisque anterioribus ssepius dilutioribus, pedibus posterioribus nigris ; antennis rufis ; elytrorum epipleuris versus apicem sat latis, planatis. Long. 35, lat. 192 m.m. 5 A 2 72,6 On Aquatic Carnivorous Coltoptera or Dytiscldce. The male has the front tarsi rather large, attaining about 83 m.m. in the transverse direction, and their pubescent area is correspondingly large ; on the intermediate tarsi the basal joint has a linear patch of rather short sexual pubescence ; the female is without sexual sculpture, or trace of rudimentary claw on the hind tarsus. This species is excessively similar to C. immarginatus, but is comparatively a httle narrower in form, the male has the front tarsi better developed, and the sexual pubescence of the intermediate feet much less : the epipleurse in their terminal portion are broader and flatter, and on the upper surface the elytra have a slight explanation at the lateral margin before the extremity. Tlie species is much larger and more elongate than C. operosus, and the male front tarsi are twice as large, and the intermediate feet with quite different sexual pubescence. From C. modestus, this species is distinguished by its more convex form and rather larger size, the larger front male tarsi, and the narrow patch of sexual pubescence on the intermediate feet, and also by the explanation of the elytra just within the lateral margin in their posterior portion ; the species has a very slight tendency to show a metallic lustre on the upper surface. A female from Damara land in my collection is perhaps a variety, it has a very slight sexual sculpture on the thorax towards the sides, the epipleuraj are slightly broader, and on one of the hind tarsi there is a very slight rudiment of a supplementary claw. Tropical Africa, (Senegal). 1068. 1139. Cybister dehaani, Aube, Trogusdchaani, M.C. — Parvus, ovalis, convexus, supra nigro-olivaceus, subtus niger, antennis pedibusque anterioribus et inter- mediis rufescentibus, pedibus postei'ioribus nigro-piceis ; elytrorum epipleuris capiteque anterius plus minusve vage rufescentibus. Long, loi, lat. 7h m.m. In the male of this species the front tarsi are small, and their pubescent area is absent ; the basal fringing hairs appear at first sight to be absent, but on careful examination they are seen to exist, although very short, and they are placed not quite at the hind margin, but I'un across the basal joint just behind the palettes, so that there is behind them a short glabrous space or heel to the tarsus ; on the intermediate tarsus there are some longf hairs on the underside of the three basal joints, those on the third joint being, however, but very few in number, and considerably shorter than those on the preceeding joints. The female has no sexual sculpture, and no trace of a supplementary claw on the hind tarsus. The species is very distinct by its small size from any other as yet known. Slam and Cambodia. 1070. On Aquatic Carnivorous Coleoptera or Dytiscidce. 117 Group 4. 1140. Dytiscus tripunctatus, 01., Tragus tripunctatus, 31. C. — Ovalis, supra olivaceo-niger, capite anterius prothoraceque lateribus testaceis, elytris margine externo (cum epipleuris) argute et sat late testaceo ; subtus piceus, metathoracis episternis abdominisque lateribus testaceo-maculatis, pedibus quatuor anterioribus testaceis, femoribus anterioribus fusco-maculatis, tibiis intermediis fusco-testaceis, tarsis intermediis pedibusque posterioribus piceis ; antennis testaceis. Long. 22—31 m.m., lat. lU— 16 m.m. The anterior tarsi of the male are rather small ; their pubescent area is of mode- rate size ; the intermediate tarsi have the two basal joints bearing well develojied jiatches of moderately short sexual pubescence, and their claws are simple, very little unequal, and in fact scarcely difierent from those of the female. The female is either entirely without sexual sculpture, or may have on the basal portion of the wing-cases, very short irregular isolated scratches ; the thorax never shows the least trace of sexual sculpture. The species is very variable in size, form, and the sexual sculpture of the females, and shows even considerable variation in the sexual pubescence of the intermediate tarsi of the male, as well as in the width of the yellow marginal cincture which varies on head thorax and elytra. I have made a careful review of its numerous variations, and give below the results. It may be said roughly that there are four forms, an Eastern Asiatic one found in China, Japan, Formosa, Mantchuria, Philippine Islands, Malay peninsula, Hindostan, and Ceylon, — as well as in Austra- lia ; while the New Caledonia individuals approach the second form which is found in the islands of the Malay archipelago, from Sumatra to Celebes, the specimens from Bourbon and Mauritius appruach very nearly to the Malasian specimens : the third form is rare and appears to occur in a sporadic manner in the Philippine Islands and the islands of the Malay archipelago. The fourth form is found in Africa and Southern Europe. The forms may be thus defined : — First, or east Asiatic form ; moderate size, rather narrow and little convex form, sexual sculpture of the females either fine or entirely wanting ; and the patches of sexual pubescence on the intermediate tarsi of the male are rather narrow, that on the second joint especially being narrow, much narrower than that on the basal joint. The second or archipelagic form, is usually of rather broader, more robust and more convex form, the sexual sculpture of the females is very variable indeed, either entirely wanting or largely developed, and the patches of sexual pubescence on the male middle tarsi are broad, that on the second joint being scarcely larger than that on the first. The third or sporadic form is of large size, broader behind the middle than the 728 On Aquatic Carnivorous Coleoptern or Dytiscidce. other, the female sexual sculpture is very lai'gely developed, while the patches of sexual pubescence on the intermediate tarsi of the male are largely developul as in the second form. The fourth or African form is usually large and very elongate, with the yellow cincture largely developed: the females never have the least trace of sexual sculp- ture, and the patches of sexual pubescence on the intermediate tarsi of the male are moderately developed, intermediate in size between those of the first and second forms, but with the hairs usually rather longer than in either. The characters are however variable, and no definite limits can be assigned to the four forms as will be seen from the following more detailed sketch of the local variations. Japan. — Eight individuals from three sources are before me from this locality : the smallest individual (a male) is 24 m.m. long, 12i m.m. broad, 7h m.m. high ; the largest (a female) 28 m.m. long, 1 4| broad, Si m.m. high : the yellow mark on the clypeus is broad, but shows in the middle a slight descent forward of the dark colour : the thoracic and elytral bands are never very broad, but are distinctly broader in some individuals than they are in others, the anterior tarsi of the male attain fully la m.m. in the transverse direction; the pubescence on the basal joint of the intermediate tarsi is intermediate in shape between a narrow triangle and an oval form, and that on the second joint forms a patch which has a nmch less width than the termination of the patch on the basal joint : the females have no sexual sculpture. A female from Formosa agrees with the Japanese individuals ; while another from Mantchuria differs only by having a fine but distinct sexual sculpture extend- ing along the middle of the wing-case, from near the base to about one-third of the distance towards the apex. Numei'ous specimens from China agree with the Japanese form, but some of the females have a well marked sexual sculpture, while others have no trace of it ; the largest individual is a female with well marked sexual sculpture, and agreeing nearly in size with the largest Japanese female, being fully 28 m.m. long, 15 m.m. broad, 9 m.m. high. In a large male the front tarsi attain quite 1| m.m. in the transverse direction. Specimens from the Malay peninsula show no further vai'iation than those men- tioned above ; the females have no sexual sculpture ; one male is of very diminutive size, 22 m.m. long, Hi m.m. broad, 7 m.m. high. From the Philippine islands numerous specimens, (some of which are labelled "Manilla") show no differences from the forms already alluded to : and the females have also variable sexual sculpture, which is sometimes completely absent. Three individuals from these islands differ, however, by their large size and by their form which is more dilated behind ; the male has the patches of pubescence on the middle tarsi much broadei", and the females a sexual sculpture on the elytra, consisting of On Aquatic Carnivorous Coleoptera or DytiscidcB, 729 short scratches which, are rather more widely separated from one another than in the form above mentioned: the size of a large specimen is 28} m.m. long, 15f m.m. wide, and 9 5 m.m. high. A few specimens from Sumatra, Borneo and Labuan, seem to be intermediate between the large broad forni just mentioned, and the ordinary East Asiatic form. In Java the species appear to be very common, and the individuals from there are of a rather short, broad, robust form, with the yellow margin to the elytra broad, and the patches of pubescence on the two basal joints of the male intermediate tarsi broad, while the sexual sculpture of the females is slight or entirely wanting ; a male measures 25 m.m, long, by 14 m.m. broad, by 85 m.m. high. The Cybister temninckii of Aube is said to be from Java, it differs from all other Javanese individuals I have seen by its very elongate form ; one of the individuals which served Aubd for his description is before me, it is a female, with slight sexual sculpture, and is fully 30 m.m. long, 15 m.m. broad, by 9 m.m. high. A small series from Celebes, Batchian, Amboina, differ scarcely at all from the Javanese individuals, but are perhaps on the average a little larger in size ; of four females before me from this locality, three have no sexual sculpture, and on the fourth the sculpture is but slight. A single female from Menado, agrees with the larger of the Philippine Island forms, except that the scratches forming its sexual sculpture are finer and denser. I have seen no specimens from New Guinea, though the species no doubt occurs there. In Australia the species is common, and I have before me a series of about twenty-four specimens from localities which indicate the species as there very widely distributed ; they differ scarcely at all from the East Asiatic form as found in China and Japan, but are perhaps on the average slightly larger in size, and the dark colour on the head usually approaches in the middle rather nearer to the labrum ; the male tarsi are the same as in the Chinese form, and all the females show a fine sexual sculpture except one which is quite smooth. In New Caledonia the species appears also common ; the individuals are rather shorter than the Australian individuals, and the patches of pubescence on the male intermediate tarsi are rather broader, so that here the specimens seem to approximate to the Javanese forms. The females have a slight sexual sculoture. One very large female from this locality is remarkable, it attains 29i m.m. in length by 16 m.m. broad, and has a largely developed sexual scidpture, so that it differs but little from the broader of the two forms mentioned as found in the Philippine Islands. Cybister artensis and C. novae-caledoniaB, as well as Dytiscus hamatus described by Montrouzier from this locality seem all to be merely varieties of D. tripunctatus. From Ceylon I have seen only a single pair, which are very small, but do not 730 On Aquatic Carnivorous Coleoptera or Dytiscidce. differ iu any definite uianaer from the East Asiatic form : tlie female has no sexual sculpture. A pair from the Andaman Islands agree tolerably with individuals from Sumatra, but are perhaps of still shorter form, and the male is very small, the dimensions being 24 by 13 by 72 m.m. From Hindostan I have seen but two or three individuals, they agree with the East Asiatic form ; the female has no sexual sculpture. The specimens from Bourbon and Mauritius are of short, robust and convex form, and the females have usually a fine sexual sculpture which occasionally is nearly or quite absent ; I cannot distinguish the specimens from these insular localities from some of the Javanese specimens. The specimens from Madagascar although extremely similar at first sight can nevertheless be always distinguished with certainty, and are therefore con- sidered by me as' a distinct species : but I believe connecting specimens will ultimately be found. The species is very abundant in Africa and is there usually of elongate form, with the lateral band on the elytra broad ; the form, however, varies a good deal, the most elongate specimen before me is 31 m.m. long, by 15^ by 9, while one of the shortest measures 27 m.m. by lih, by 8^; the females never show any sexual sculpture, and the tarsi of the male do not differ in any appreciable manner from what obtains in the Australian individuals ; indeed many Australian individuals are quite indistinguishable from African ones, yet in Africa the females never have sexual sculpture while in Australia they nearly always possess such. The most elono-ate and peculiar of the African specimens are found in South Africa. The specimens found iu the South of Europe quite agree with the African in- dividuals. The Nubian Trogus haagi, Wehncke, and the Caucasian C. gotschi, Hoch., are both pretty certainly to be referred to this species. 1141. Cybister cinctus, n. sp. — Ovalis, convexus, supra olivaceo-niger, epistoma totum prothoraceque lateribus late testaceis, ely tris margine externo (cum epipleuris) argute et late testaceis, subtus piceus, metathoracis episternis abdominisque lateribus testaceo-maculatis ; pedibus quatuor anterioribus testaceis, femoribus anterioribus fusco maculatis, tibiis intermediis tarsisque pedibusque posterioribus piceis ; antennis testaceis. Long. 27, lat. 14* m.m. This species or race greatly resembles such convex forms of D. tripunctatus as have the yellow cincture very broad, it has, however, the yellow colour on the front of the head and at the sides of the thorax extended over a larger area than in any of those forms ; certain individuals from tropical Africa approximate a good deal to it in this respect, but the females found in Africa never have the least sexual On Aquatic Carnivorous Coleoptera or Dytiscidw. 731 sculpture, whereas the present species has in that sex, a perfectly distinct although very fine sexual sculpture of excessively short scratches near the base of the wing- cases ; the form too, is always shorter than in the African individuals which most resemble it ; the male front and middle tarsi seem quite the same as in the African specimens. Madagascar. 1072. 1142. Cybister asiaticus, n. sp. — Ovalis, supra olivaceo-niger, capite anterius prothoracisque lateribus testaceis, elytris margine externo (cum epipleuris) argute et sat late testaceo ; subtus variegatus, pectore testaceo, in medio ferrugineo vel piceo, ad latera anguste nigricante, prosterno abdomineque picescentibus ; pedibus quatuor anterioribus testaceis, femoribus anterioribus fusco-maculatis, tarsis intermediis piceis ; pedibus posterioribus tibiis tarsisque piceis, femoribus rufescentibus ; antennis testaceis. Long. -2,7, lat. 14? m.m. The anterior tarsi of the male are rather small, and similar to those of Dytiscus tripunctatus ; the two basal joints of the intermediate tarsi bear rather narrow patches of moderately short sexual pubescence, that on the second joint being a good deal narrower than that of the basal one : there is sometimes an extension of this pubescence on to the third joint. The female never has any trace of sexual sculpture. This species is closely allied to Dytiscus tripunctatus, but is readily distinguished by the colour of the undersurface ; the whole of the epistome is yellow, the lateral band of the elytra is very similar to that of D. tripunctatus, that is to say it is sharply defined even to the apex of the elytra, near which it shows a hook-like dilatation, beyond this becoming narrower till it touches the suture as a point. The species varies much in size, and as a rule the largest individuals show the greatest extension of dark colour on the undersurface. India, Persia, Mesopotamia. (Nortliern India, Calcutta, Central India; Northern Persia, 1862-3, Doria ; Mesopotamia Dr. Millingen). 1073. 1143. Cybister fumatus, n. sp. — Ovalis, parum elongatus, convexus, supra olivaceo-niger, capite anterius prothoracisque lateribus testaceis, elytris margine externo (cum epipleuris) sat late testaceo ; corpore subtus piceo, pectore prope latera plaga vaga ferruginea ; pedibus quatuor anterioribus testaceis, femojibus anterioribus fusco-maculatis, tibiis intermediis fusco-testaceis, tarsis pedibusque posterioribus piceis : antennis testaceis. Long. 24, lat ISi m.m. The anterior tarsi of the male are small, and nearly similar to those of Dytiscus tripunctatus ; the intermediate feet have rather narrow patches of sexual pubes- cence on the three basal joints, that on the third joint being quite narrow, that on the second intermediate in width between the other two. The female has on the TBANS. BOY. DUI3. SOC, N.S., VOL. II. -3 IS 732 On Aquatic Carnivorous Coleoptera or DytiscidoB. basal portion of the wing-cases a fine sexual sculpture consisting of very short isolated scratches. The species differs from C. asiaticus, by its form which is broader in front and more convex, the colour of the undersurface is darker and the female has a fine sexual sculpture. The hook-like dilatation near the termination of the elytra is less distinct, and the terminal portion of the band is less deBnite : the epistome is nearly entirely yellow, but there is generally a little descent of the dark colour in the middle so as to diminish there the length of the yellow mark. It also resembles excessively the Javanese varieties of D. tripunctatus, but is smaller, has a pale patch on the sides of the breast ; and the patches of pubescence on the intermediate male tarsi are narrower, and extend on to the third joint. Siam, and interior of Malay peninsula, Castlenau. 1074. 1144. Cybister lewisianus. Sharp, Tr. Ent. Soc. Lond. 1873, p. 46. — Ovalis, convexus, anterius evidenter angustatus, supra olivaceo-niger, capite anterius prothoracisque lateribus testaceis, elytris margine externo (cum epipleuris) sat late testaceo ; corpore subtus testaceo, ad latera anguste nigricante, pectore in medio plus minusve infuscato ; pedibus quatuor anterioribus testaceis, tarsis intermediis piceis ; pedibus posterioribus femoribus rufis, tibiis tarsisque nigricantibus ; elytrorum epipleuris versus apicem distincte latioribus et planatis ; processubus co.xalibus apice conjunctim fere truncatis. Long. 25, lat. 14 m.m. The male anterior tarsi are small, but do not differ much from those of D. tripunctatus ; the intermediate feet appear at first entirely destitute of sexual pubescence, but on careful examination there is seen a narrow line of very short hairs on the first two joints. The female has no sexual sculpture. Although very similar to C. asiaticus and C. fumatus the species is readily distin- guished by the form of the coxal processes which are soldered together to the apex so that there is scarcely any notch between them : the epipleurae before their termination are also slightly, but undoubtedly, broader than in the allied species. The specimens from China are larger and broader than those from Japan, and the colour of the undersurface is darker in the middle. Japan, China, (Shanghai, Felder and Abbe David), Assam. 1075. 1145. Cybister senegalensis, Aub^, Trogus senegalensis, M.C. — Minor, ovalis, sat convexus, parum latus, supra olivaceo-niger, capite anterius prothoracisque lateribus testaceis, elytris margine externo (cum epipleuris) sat late testaceo ; corpore subtus nigricante, pedibus quatuor anterioribus testaceis, tarsis intermediis pedibusqne posterioribus picescentibus, antennis testaceis. Long. 20, lat. 10 m.ru. On Aquatic Carnivorous Coleoptera or Dytiscidcs. 733 The male anterior tarsi are small ; and on the intermediate feet the three basal joints are furnished beneath with rather short sexual pubescence, the patch on the basal joint is broad, that on the third joint quite narrow, the one on the second joint being intermediate in width. The female has no trace of any sexual sculp- ture. The species is readily distinguished amongst its allies by its small size : it varies somewhat in form ; some individuals being notably more elongate than others, it also varies somewhat in the colour of the undersurface, this being sometimes nearly black, more rarely piceous red. Algeria, Senegal, Madagascar. 1076. 1146. Cybister occidentalis, Aube, Trogus occidentalis, 21. C. — Latus, ovalis, parum convesus, nitidus, niger, parum olivaceus, capite anterius prothoraceque ad latera testaceis, elytris margine externo (cum epipleuris) late testaceo ; pedibus anterioribus rufis, femoribus fusco-maculatis, intermediis piceis, femoribus basi apiceque rufescentibus, posterioribus nigricantibus, femoribus angulo externo posteriore recto : antennis rufis ; elytrorum epipleuris versus apicem sat latis et planatis. Long. 33, lat. 19 m.m. The male has the front tarsi rather large in the transverse direction ; the intermediate feet bear patches of moderately short sexual pubescence, on the three basal joints, the basal patch is broader than the others, that on the thirdjoint being quite narrow, the claws are rather long and stout, curved and distinctly unequal ; in the hollow just in front of the articulation of the swimming legs there are four or five coarse, short, raised ridges. The female has a well marked sexual sculpture on the wing-cases and thorax ; on the former there are fine scratches of variable length, some of them elongate, they are directed in the long axis of the body and show a tendency to converge or anastomose here and there, at the base they extend from the scutellum to the shoulder, elsewhere they reach neither to the suture nor to the lateral margin although they invade the inner portion of the yellow band ; they reach about four-fifths of the way to the apex ; on the thorax the scratches are short, and not numerous, they are also absent altogether from the disc ; on the head there are some fine scratches behind the eye. In this as in the following species, the yellow band at the apex of the elytra does not terminate in quite a point at the suture, so that it is distinctly connected with that on the other wing-case. I have seen specimens of this species in more than one collection, said to be from Montevideo and Buenos Ayres, but I believe erroneously. Owba. 1077. S B 3 734 On Aquatic Carnivorous Coleoptera or Dytiscidoe. 1147. Cybister esplanatus, Lee, Tragus explanatus, M.C. — Ovalis, convexus,. parum latus, supra olivaceus, capite anterius prothoraceque ad latera testaceis, elytris margine externo, (cum epipleuris) late testaceo ; subtus ferrugineus, iu medio plus minusve olive?cens, pedibus quatuor anterioribus testaceis, tarsis interrnediis picescentibus, pedibus posterioribus ferrugineis, tarsis magis picescentibus, femori- bus angulo externo posteriore spinoso-acuto ; elytrorum epipleuris versus apicem sat latis et planatis ■ Long. 27, lat, 14^ m.m. The male has the anterior tarsi moderately large ; the intermediate tarsi have the three basal joints with long sexual hairs beneath, there is a slight development on the fourth joint of sexual pubescence, and on the fifth joint the setjB have under- gone a partial transformation into long sexual pubescence. The female has fine sexual sculpture largely distributed over the thorax and head, but none at all on the wing-cases. Both male and female have in the hollow near the articulation of the swimming legs four or five short, coarse folds or ridges, these are better developed in the male than in the female. This is a very distinct specie.? bearing a superficial resemblance to Cybister ellip- ticus Lee, (No. 1120). It has a tendency to development of yellow colour along the anterior and posterior margins of the thorax. North America. (California). 1078. 1148. Cybister reichei, Aube, Tragus reichei, M.C. — Minor, ovalis, parum con- vexus, fere angustus, nitidus, capite oHvaceo, anterius late testaceo, prothorace ad latera et ad marginem anteriorem testaceo, basi in medio late olivaceo, elytris olivaceis, late testaceo-cinctis ; corpore subtus testaceo, pectore in medio prosternique processu obscurioribus, tarsis intermediis, tibiis tarsisque posterioribus piceo-rufis ; elytrorum epipleuris versus apicem latis et planatis ; trochanteribus posterioribus apice libero, spinoso-acuto. Long. 20, lat. 9| m.m. The male has the anterior tarsi small ; the intermediate feet with the three basal joints largely furnished beneath with rather short sexual hairs, and their claws a little elongate. The female has fine, short, distant scratches on the basal portion of the wing-case, and on the thorax. This little species cannot be confounded with any but the following one on account of the spinose posterior trochanters. The extent of the dark colour on the thorax is no doubt variable ; the yellow band of the elytra does not terminate in a point at the suture, but is joined distinctly to the band on the other wing-case. There is some doubt as to the habitat of this little known species. Aube was acquainted with only two individuals, one of which was said to be from Brazil the other from Senegal. I have myself seen only two individuals, a male from Chevrolat's collection, labelled " Egypte, Flourens," and a female in my own collection On Aquatic Carnivorous Coleoptera or Dytiscidce, 735 which I have possessed for a good many years, without label or indication whence I obtained it, but I believe it was from M. Doue's collection. I should think Upper Egypt is undoubtedly its country, and it may occur also in Senegal. Egypt, (Senegal?). 1079. 1149. Cybister crassipes, n. sp. — Minor, ovalis, robustus, latiusculus, parum elongatus, supra olivaceus, capite anterius prothoraceque ad latera late testaceis, elytris late testaceo-cinctis ; corpore subtus testaceo, prosterno pectoreque in medio obscurioribus, tarsis intermediis, tibiis tarsisque posterioribus piceo-rufis; elytrorum epipleuris versus apicem latis et planatis ; trochanteribus posterioribus apice libero, spinoso-acuto. Long. 22, lat. 12 m.m. I have not seen the male of this species : the female possesses a rather dense but fine sexual sculpture on the wing-cases and thorax ; this sculpture consists of moderately fine scratches some of which are quite short, others elongate, at the base this sculpture extends from the scutellum to near the lateral margin, and it extends also two-thirds of the distance towards the apex, but becomes more distant both from the suture and lateral margin as it proceeds backwards ; the thorax is nearly covered with irreafular scratches but there are none at all on the head. The single individual 1 have seen indicates that this species is closely allied to Cybister reichei, but is of broad instead of narrow form . Arabia, (Dr. C. Millingen). 1080. 1150. Cybister tibialis, n. sp. — Ovalis, sat latus, anterius evidenter angustatus, supra niger, capite anterius prothoraceque ad latera testaceis, elytris margine externo (cum epipleuris) testaceo-cinctis ; subtus piceus, pectore ad latera late testaceo ; pedi- bus quatuor anterioribus testaceis, tibiis intermediis piceo- testaceis, tarsis intermediis pedibusque posterioribus piceis ; elytrorum epipleuris versus apicem sat latis et planatis. Long. 30, lat. 16 m.m. The male has the anterior tarsi large attaining fully 3 m.m. in the transverse direc- tion ; on the intermediate tarsi there is a patch of quite short sexual pubescence on each of the three basal joints, these patches are not very broad, that on the third joint being indeed quite narrow, the claws are rather elongate and little curved, the anterior one much thickened. The female has a largely developed sexual sculpture on the wing-case, consisting of elongate scratches or striae, which however scarcely anastomose with one another, they extend about three-fourths of the way to the apex, at the base they extend quite across the wing-case, and for nearly their whole length are but little separated from the lateral margin ; on the thorax there are very fine short scratches on the lateral parts and extending along the base : the epipleurse are oblique, though not dilated in front of the middle. This species attains the size of the smallest individuals of Dy tiscus roeselii (N o. 1 1 6 9 ) 736 On Aquatic Caniivorous Coleoptera or Dytiscidce. butislessbroad behind : it standsabout equally near to that species and to the Dytiscus tripunctatus group of species: it is readily distinguished from D. rceselii by the lateral bandof theelytrawhichissimilar to that of D.tripuuctatusand by the sexual characters, the female having no swimming ciUa3 along the outer margin of the hind tarsi beneath, and the male having a largely developed sexual pubescence on the intermediate tarsi From C. asiaticus (No. 1 1 42), the species of the D. tripunctatus group to which it has the most resemblance on account of the colour of its undersurface, it is readily distinguished by the broader epipleura;, and the difierent sexual characters ; the anterior tarsi of the male being large, and the female having sexual sculpture on the thorax. I have seen only a single pair of this interesting species ; the male was in Castlenau's collection, labelled, " Cybister tibialis, Keich. Madagascar" ; the female is in M. de Bonvouloir's collection and bore no other indication of locality than a blue ticket on the pin. I have no doubt that Madagascar is the habitat. Madagascar. 1081. 1151. Cybister pectoralis, n. sp. — Robustus, ovalis, convexus, sat latus, parum nitidus, supra nigricans, capite anterius prothoraceque ad latera testaceis, elytris vitta raaro-inali ad apicem angustissima ad basin lata (cum epipleuris) testacea ; subtus fusco-piceus, coxis posterioribus externe macula parva testacea, metasterno gibboso, laciniis impressis ; pedibus quatuor anterioribus testaceis, posterioribus nigricantibus ; elytris transversim rugosulis, epipleuris versus apicem latis. Long. 23, lat. 13, alt. 8i m.m. The male has the front tarsi rather large, but their pubescent area on the under- surface is small : the middle feet have the three basal joints furnished with very lono- sexual hairs, their claws are rather long, but slender : the female has the basal portion of the elytra covered with dense short scratches, which extend about half way to the apex, but in their terminal portion are very obscure, the thorax is nearly covered with short deep scratches so densely placed as to render the surface ruo-ose, but they do not extend to the head, and indeed leave even the anterior maro-in of the thorax (in front of the transverse series of punctures) smooth. This species is a most remarkable one, owang to the peculiar conformation of its undersurface ; the metasternum in front is swollen or gibbous, and the breast of a peculiar metallic colour along the middle ; the curved series of punctures which runs parallel with the inner margin of the middle coxal cavities are peculiarly deep and coarse. I have seen only a pair of this species, the male I purchased from a dealer about twelve years ago wdth the locality India ; the female w^as in the collection of M. Castlenau, labelled " India, Deccan." East India. 1082. On Aquatic Carnivorous Coleoptera or DytiscidcB. 737 Group 5. 1152. Cybister wehnckianus, n. sp. — Minor, ovalis, fere angustus, parum nitidus, supra nigricans, capite anterius prothoraceque ad latera testaceis ; elytris vitta submarginali angusta ante apicem omnino obsoletescente testacea, epipleuris nigricantibus ; subtus piceus, coxis posterioribus externe vage testaceo-maculatis, metasterno anterius subprominulo, laciniis impressis, pedibus quatuor anterioribus testaceis, femoribus in medio tibiisque intermediis obscurioribus, pedibus posteriori- bus nigricantibus ; elytris transversim rugosulis, epipleuris versus apicem latis. Long. 20, lat. 11 m.m. I have not seen the male of this species ; the elytra has on the basal portion of the elytra rather numerous short irregular scratches, which do not reach either to the suture or lateral margin, and, becoming very obscure as they extend backwards, cease entirely about half way to the apex : the thorax is almost free from sexual sculpture, although its surface is uneven ; on careful examination however traces of excessively fine short scratches may be detected along its basal portion. This species seems allied to the preceding one although very distinct therefrom ; the gibbosity of the anterior part of the metasternum is indistinct, but the coarse series of punctures, and the impressions on its lacinise are much the same ; the colour of the epipleurse of itself renders the two species very distinct. India (^). 1083. 1153. Cybister cephalotes, n. sp. — Ovalis, sat latus, antei'ius parum angustatus, capite majore ; supra olivaceus, capite anterius prothoraceque ad latera testaceis, elytris vitta Integra determinata laterali cum epipleuris testaceis, his externe nigro- lineatis ; subtus niger ; pedibus anterioribus et intermediis rufis, nigro-variis, posterioribus nigricantibus; prothorace ad latera subimpresso. Long. 28, lat. 14 m.m. The male has the front tarsi rather small, and their pubescent area is small ; on the middle tarsi the two intermediate joints bear moderately long sexual hairs, and there is a very slight development of sexual pubescence on the folio wing joint : the female has a patch of peculiar sexual sculpture along the middle of the wing-case but not reaching the base ; this sculpture consists of very short, deep, punctiform im- pressions, mixed with which are some short angular or curved impressions and numerous fine punctures, but extends only over a small space and is widely separated both from the suture and lateral margin. This species is a peculiar one, bearing a considerable resemblance to Dytiscus tripunctatus{No. 1140), but has the head larger, and the thorax with a sort of impression along the side ; the form of the yellow band along the elytra is quite as in D. tripunctatus, but the epipleurse externally are margined with dark colour ; 738 On Aquatic Carnivorous Coleoptera or DytiscidcB. the series of punctures along the middle coxal cavity is coarse, although somewhat obsolete and irregular, but there is no gibbosity of the metasternum ; the epipleurse are but little dilated in their posterior portion. The specimens I have seen are in bad condition. Abyssinia, Raffray and Beccari, (Lebka, Bogos.) 1087. 1154. Cybister buqueti, Pi.uhe,Trogus huqueti, M.C. — Major,ovalis,latus,convexus, anterius conspicue angustatus, supra niger, capite anterius et prothorace marginibus omnibus testaceis, elj^ris vitta intra.marginali (ad apicem suturam fere attingente) testacea ; subtus testaceus, capite pectoreque in medio fuscis, pedibus anterioribus testaceis, posterioribus piceis, femoribus apice testaceo ; elytrorum epipleuris ante apicem latis ; trochanteribus posterioribus apice libero, acuto. Long. 39 m.m., lat. 22 m.m., alt. 13 m.m. The male has the front tarsi rather small, attaining about 3 m.m. in the transverse direction ; the two basal joints on the middle tarsi have each along the middle an elongate, narrow patch of short sexual pubescence, their claws are rather short and slender, but a good deal unequal; in the hollow near the articulation of the hind coxse there are about ten short, coarse depressions or grooves. The female is unknown. This and the following species are remarkable by their thorax being entirely margined with yellow, just in the same way as Dytiscus marginalis and its allies : at the sides the margin is very broad, in front it is moderately broad, but at the base narrow, so that on each side it almost thins out before joining the lateral yellow band. Africa, (Senegal.) 1085. 1155. Cybister dytiscoides, n. sp. — Major, ovalis, convexus, anterius angustatus, supra niger, capite anterius prothoraceque marginibus omnibus testaceis, elytris vitta intraroarginali (ad apicem suturam fere attingente) testacea ; subtus testaceus, capite et medio pectoris nigricantibus; pedibus anterioribus testaceis, posterioribus piceis, femoribus apice testaceo; trochanteribus posterioribus apice libero, acuto. Long. 37 m.m., lat. 191 m.m., alt. 12| m.m. The male has the front tarsi small, attaining about 2i m.m. in the transverse direction ; the two basal joints of the intermediate tarsi have each along the middle a broad patch of short sexual pubescence ; in the hollow near the articulation of the hind coxae, there are five or six short longitudinal depressions, these depressions are irregular and the inner two or three quite obscure. This species is very closely allied to Cybister buqueti : the only specimen 1 have seen indicates a smaller species, with broader patches of sexual pubescence on the On Aquatic Carnivorous Coleoptera or DytiscidcB. 739 intermediate tarsi ; it has too the presternum with its anterior front ano-le much rounded off, whereas it is prominent and robust in Cybister bnqueti. Madagascar. 1086. 1156. Cybister confusus, n. sp. — Major, ovahs, niger, capite anterius prothorace- que ad latera testaceis, elytris vitta intramarginah (apice parum hamato-dilatata), suturam attingente testacea; corpore subtus nigricante, pedibus anterioribus et intermediis rufis, liis tibiis infuscatis. Long. 36, lat. 192 m.m. In the male the front tarsi are large, attaining 4 m.m. in the transverse direction ; the intermediate tarsi have on each of the two basal joints a very large broad patch of quite short sexual pubescence, and there may generally be seen a line of rudi- mentary pubescence on the third joint, their claws are rather long, the outer one is thick and but little curved till near the apex when it takes a sudden bend, the inner one is shorter and much thinner. The oedeagus has the inferior lobe with its apical part oblong in form, (becoming however just slightly broader towards the extremity), and its apex shows a deep ^vell marked notch ; the dorsal lobe termi- nates in two contiguous processes, which reach as far as the apical notch, they are flattened and roughened near the apex which is minutely turned upwards. The female has a very highly developed sexual sculpture, the thorax being covered with short, curved, or angular, irregularly directed scratches; these scratches entirely cover the thorax (except the front margin) though they are usually finer about the middle than at the sides ; the epipleurfe of the elytra are flattened and obliquely horizontal, but not very broad, the obliquity commences very near the base, and ceases in a gradual manner at about the hind margin of the second ventral seo-ment. Although this species is excessively similar to the following one and universally mixed with it in collections, it is nevertheless perfectly distinct, the form of the cedeagus in the male being characteristic and quite constant ; while the female has the epipleurte in their flattened part less broad. As smaller characters, it may be mentioned that the form of this species is usually flatter with the outline less curved at the sides, and with the yellow band of the elytra not forming a well marked hook near the apex, and nearly or quite attaining the suture; while the female has the sexual sculpture less absent along the mesial line of the body. India, Ceylon, China, (this latter locality somewhat doubtful). 1087. 1157. Dytiscus limbatus, Fab., Tragus limhatus, M.C. — Major, ovalis, supra olivaceo-niger, capite anterius prothoraceque ad latera testaceis, elytris vitta intra- marginali testacea, apice argute hamato-dilatata, suturam hand attingente ; corpore subtus nigricante, pedibus anterioribus et intermediis rufis, his tibiis infuscatis. Long. 34, lat. 19* m.m. o TKANS. EOY, DUB. SOC, N.S., VOL. II 740 On Aquatic Carnivorous Coleoptera or Dytiscida;. The front and middle tarsi of this species are similar to those of C. confusus ; but the cedeagus presents constant and well marked differences ; its inferior lobe becomes narrower till close to the termination, when it becomes much broader, its exti'emity is broadly emarginate, so that it has a furcate appearance, and is also arched in the transverse direction ; the dorsal lobe terminates in two processes which do not extend to the ajiex, and which diverge from one another before their termination, the apices however are again a little incurved, but not contiguous, being separated in the condition of repose by a broad longitudinal elevation which runs along the middle of the under lobe. The female has a highly developed sexual sculpture, similar to what exists in C confusus, but less distinct on the disc of the thorax, and absent from a rather wider space along the suture of the wing- cases. The epipleuraj of the elytra are flattened and obliquely horizontal, and rather broad, the torsion commences very close to the shoulder, and ceases in a gradual manner about the hind margin of the second ventral segment. The species is a rather variable one ; and there may be distinguished three varieties : the first is of short, convex form a good deal narrowed in front, and the sculpture of the female on the thorax and elytra is comparatively less developed, extending on the latter only three-fifths of the length towai'ds the extremity ; this is especially common in northern China and Mantchuria if I may judge correctly from the material before me ; the second form is more elongate, and rather flatter and the sculpture of the female is nearly as largely developed as in C confusus, extending four-fifths or five-sixths of theh" length ; I have individuals of this variety from Shanghai. The third form is broad and robust, and the yellow band of the elytra has a tendency to be prolonged nearer to the suture at the extremity, and the female sculpture is largely developed ; this variety occurs I believe in Southern Hindostan (Madras). In all the variations of this abundant insect the form of the cedeagus remains absolutely without variation ; the varieties in colour, form, &c., already alluded to, merge quite gradually into one another by intermediate specimens. Mantchuria, China, Formosa, Southern India. 1088. 1158. Cybister guerini. Tragus guerini, M.C. — Ovalis, niger, ca2)ite anterius prothoraceque ad latei'a testaceis, elytris vitta intramarginali testacea, ad apicem haud argute hamato-dilatata, suturam hand attingente, pedibus anterioribus et intermediis rufis, femoribus late nigricantibus, tibiis tarsisque intermediis fere nigris. Long. 34, lat. 19^ m.m. The male has the front and middle tarsi the same as in C confusus and D. limbatus ; and in the structure of its cedeagus is intermediate between the two ; the female has a highly developed sexual sculpture, the thorax beingentirely covered with irregular scratches, and the elytra bearing elongate longitudinal scratches, these On Aquatic Carnivorous Coleoptera or Dytiscidce. 741 entirely cover them at the base, behind the base leave a narrow space along the suture smooth, and at the apex leave about one-sixth of the length uncovered : the epipleurse are flattened and oblique, but this torsion does not extend farther back than the first ventral segment. The species varies a good deal in size and especially in width, but is easily discri- minated from the preceding one, by the colour of the front and middle femora ; the wing-cases of the males generally bear excessively fine tubercles, with rudiments of transverse aoiculations between them, thus showing a slight development of the sculpture which becomes so remarkable in C. rugosus. Aube's description of the female of C. guerini was probably taken from another species, for he states that it has very little sexual sculpture, I have seen only a single example agreeing with this statement, and think it very probably a distinct species. Mantcliuria, China, Siam, Laos, Java, Celebes. 1089. 1159. Cybister bengalensis, Aube, Trogus hengalensis, M.C — Ovalis, supra olivaceus, capite anterius prothoraceque ad latera testaceis, elytris vitta intra- marginali, apice hamato-dilatata, suturam haud attingente, testacea ; corpore subtus variegato, ex parte majore nigro, pectore utrinque late testaceo, abdomine nigro, segmento basali plaga laterali testacea, segmentis 3 — 5 testaceo-maculatis ; pedibus quatuor anterioribus testaceis, tarsis intermediis pedibusque posterioribus nigricantibus, his femoribus apice rufo ; elytris extrorsum versus apicem subtiliter sed perspicue coriaceo-rugulosis. Long. 292, lat. 16 m.m. The front tarsi of the male attain scarcely 3 m.m. in the transverse direction ; the intermediate feet have rather large patches of sexual pubescence on the two basal joints and generally an obscure narrow patch on the following joint. The female has no trace of any sexual sculpture, and the epipleurse are quite simple as in the male. The species seems to vary but little ; I have seen only one specimen stated to be from India, and I consider it doubtful whether it occurs there. I have little doubt, from individuals before me, that other species with a similar colour of the undersurface exist, differing, however, in the sexual characters. As regards the name of the species, this is the only one to which Aube's description is applicable ; but as far as I know it is found only in China, but the French author says it occurs " aux Indes crientales et en Chine " ; it is possible, therefore, that his description was made from Chinese examples, and the epithet " bengalensis " was used for the species because individuals from Bengal were supposed to be con- specific. Chiuii ; especially towards the North. (Sechuan, A. Da-vid.) 1090. 5 C 2 742 On Aquatic Carnivorous Coleoptera or Dytiscida. 1160. Cybister gracilis, n. sp. — Ovalis, fere angustus, supra nigricans, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali, ad apicem parum argute delimitata, testacea ; corpora subtus variegato, ex parte majore testaceo, j^rosterno pectoreque in medio nigricantibus, abdomine testaceo fuscoque fasciato, segmentis 2° et 3'^ ex parte majore fuscis ; pedibus anterioribus et intermediis testaceis, his tarsis piceis, pedibus posterioribus piceis, femoribus ad apicem et supei-ne testaceis. Long. 28, lat. 15 m.m. The male has the front tarsi large (in proportion to the size of the insect), being fully 3 m.m. in the transverse direction ; and the intermediate feet have large patches of short sexual pubescence on the two basal joints, as in the allied species ; the female is unknown to me. This species is of narrow form, and more oblong than its allies, and the colour of the outer margin of the elytra is such that the yellow band is less distinctly limited externally ; the wing-cases are without coriaceous rugosity ; the different colours of the undersurface are sharply defined, the yellow being notably predominant. India. 1091. 1161. Cybister ventralis, n. sp. — Ovalis, sat latus, anterius evidenter angustatus, supra olivaceo-niger, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali, versus apicem hamato-dilatata, teniii, testacea ; corpore subtus variegato, ex parte majore testaceo, prosterno pectoreque in medio nigricantibus, abdomine testaceo nigroque fasciato ; pedibus anterioribus et intermediis testaceis, his tarsis piceis ; pedibus posterioribus nigricantibus femoribus ad apicem late rufis. Long. 31, lat. 17 ui.m. Thi! male front tarsi are large attaining 3j m.m. in the transverse direction ; the intermediate feet bear a large patch of short sexual i^ubescence on each of the two basal joints as in the allied species. I have not seen the female. This insect is of broader less oblong form than the preceding one ; the dark colour on the second and third ventral segments does not extend to the outside of the segments, which remains yellow. India, (Madras). 1092. 1162. Cybister chinensis, Motsch., Tragus chinensis, M.C. — Ovalis, supra nigri- cans, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali, versus apicem hamato-dilatata, testacea ; corpore subtus variegato, ex parte majore testaceo, prosterno pectoreque in medio nigricantibus, abdomine testaceo nigroque fasciato ; pedibus anterioribus et intermediis testaceis, his tarsis piceis ; pedibus posterioribus nigricantibus, femoribus ad apicem late rufis ; elytris versus apicem subtilius coriaceo-rugulosis. Long. 282, lat. 15^ m.m. The male has the front tarsi rather large, attaining 3 m.m. in the transverse direction ; the intermediate feet are as in the allies. Un Aquatio Carnivorous Colcoptera or DytiscidcB. 543 This species is closely allied to C. ventralis, but is smaller, and the elytra are finely coriaceous-rugulose in their hinder part. A female, possibly belonging to this species, agrees closely with the corresponding sex of C. crassus, except that it is more elongate and less convex; if it be really the female of this species it is of more elongate form than the male: it is 30? m.m. long, by I64 m.m. broad. Motschoulsky's description of Cy bister chinensis is very deficient, but as the present is the only species known to me to which it is applicable, I have adopted the name with some doubt as to the propriety of so doiug. China, (Mus. Castlenau). 1093. 1163. Cybister crassus, n. sp. — Ovalis, robustus, convexus, supra nigricans, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali, versus apicem hamato-dilatata, testacea ; corpore subtus variegato, ex parte majore tes- taceo, prosterno pectoreque in medio nigricantibus, abdomine testaceo nigroque fasciato ; pedibus anterioribus et intermediis testaceis, his tarsis piceis ; pedibus posterioribus nigricantibus, femoribus ad apicem late rufis ; elytris versus apicem subtilius coriaceo-rusfulosis. Long'. 30i, lat. IGi m.m. The male has the front tarsi large attaining Z\ m.m. in the transverse direction ; the intermediate feet as in the allied species. The female has a highly developed sexual sculpture, the thorax being covered with curved irregular scratches, and the elytra with deep elongate ones, which extend about four-fifths of the length, and either reach quite to the suture or leave a narrow elongate space along it smooth ; the epipleurse in this sex are flattened and obliquely perpendicular, the torsion commencing near the base, and disappearing in a gradual manner about the hind margin of the second ventral segment. This species is larger than the preceding one to which it is very closely allied ; although it and the three preceding species are so extremely similar, the oedeagus presents in each slight distinctions, which I beheve will prove to be characteristic. A female of this species existed in Dej can's collection, where it was ticketed as a variety of " Dytiscus limbatus." India, (Sylhet;. 1094. 1164. Cybister javanus, Aube, Spec. p. 59. — Major, ovalis, latus, supra olivaceo- niger, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali, versus apicem hamato-dilatata, testacea ; corpore subtus variegato, prosterno pectore- que in medio nigricantibus, abdomine ex parte majore fuscescente, segmentis ad latera testaceis ; pedibus anterioribus et intermediis testaceis, his tarsis piceis ; pedibus posterioribus nigricantibus, femoribus ad apicem rufis; elytris versus apicem subtiliter coriaceo-rugulosis. Long. 34, lat. 19i m.m. 744 Oil Aquatic Carnivorous Coleoptera or Dytiscidce. The male has the front tarsi large, attaining 4 m.m. in the transverse direction ; the two basal joints of the intermediate feet are entirely clothed beneath with short sexual pubescence. The female has a highly developed sexual sculpture, the thorax being entirely covered with short irregular scratches, and the elytra having elongate scratches on all but about the hinder one-sixth of their surface, the scratches how- ever do not quite attain the suture except at the base ; the epipleurae are flattened and obliquely horizontal, the torsion commencing near the base and ceasing gradually about the hind margin of the second ventral segment. The variegation of the antral segments is in this species indefinite, the first and second ones are largel}' pale towards the sides, while the yellow lateral colour on the following segments assumes more the form of indefinite yellow spots. The locality of this species is open to some little doubt. I have a pair from W. W. Saunders' collection, labelled " bengalensis, Aube," but with no locality ; another specimen stood in Dejean's collection labelled "Dytiscus javanus, mihi h. in Ins. Java ;" a fourth individual stood in Chevrolat's collection as one of three in- dividuals under the label "Cybister ]imbatu&,Fab. Dj. Aube, aciculatus Olivier, India or. ex Mus. olivieri ;" the other two individuals were females of Dytiscus limbatus. India (?) (Java?). 1095. 11(55. Cybister cognatus, n. sp. — Major, ovalis, supra olivaceus, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali, versus apicem argute harnato-dilatata, testacea ; corpore subtus variegato, prosterno pectoreque in medio nigricantibus, abdomine in medio late fuscescente, lateribus late vageque testaceis ; pedibus anterioribus et intermediis testaceis, his tarsis piceis, pedibus posterioribus nigricantibus femoribus ad apicem rufis. Long. 35, lat. 193 m.m. The male tarsi are only moderately large attaining about 3 m.m. in the transverse direction; on the intermediate feet the patches of short sexual pubescence on the first and second joints seem to be a good deal smaller than in the allies, the one on the second joint being quite narrow. The sexual sculpture of the female is but moderately developed, being obsolete on the thorax, and on the elytra extending only about half way to the apex, and being broadly absent along the sutural region ; the epipleurae are only slightly and obscurely flattened, and the torsion extends but for a small distance in the longi- tudinal direction. This species bears an extreme resemblance on the upper side to Dytiscus limbatus (No. 1157) but is readily distinguished by the colour of the undersurface : it is allied to the preceding species, but is distinguished readily enough, the form being less narrow in front, and less convex, the dark colour on the undersurface is less exten- sive, and the male tarsi are different, and the sexual distinctions in the female much feebler. The two species differ moreover remarkably from all their allies by the highly developed and remarkable structure of the oedeagus. On Aquatic Carnivorous Coleoptera or Dytiscidce. 745 I hgive seen only four individuals of this species ; three were in Castlenau's collec- tion, labelled "Cybister javauus, Aube, Java;" the fourth specimen is in M. de Bonvouloir's collection, labelled "Javanus'" but without locality. The specimens were all in very bad condition, and all four evidently from one source. Java. {]) 1096. 1166. Cybister celebensis, n. sp. — Ovalis, supra olivaceo-niger, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali, versus apicem hamato- dilatata, testacea ; subtus niger, pectore utrinque late testaceo, abdomine segmen- tis 3-.5 ad latera testaceo-maculatis ; pedibus quatuor anterioribus testaceis, tarsis intermediis piceis ; pedibus posterioribus nigricantibus, femoribus ad apicem late rufis; elytris versus apicem subtiliter sed perspicue coriaceo-rugulosis. Long. 29, lat. 16 m.m. The male front tarsi are rather laro-e, beings about 3 m.m. in the transverse direction ; the intermediate feet have a large patch of short sexual pubescence on each of the two basal joints. The female has a highly developed sexual sculpture, the thorax being nearly covered with irregular rather fine scratches, and the elytra bear elongate scratches which extend about four-fifths of the length, but leave the sutural portion smooth except at the base ; the epipleurse are somewhat flattened and oblique The species is closely allied to the following one, but is really distinguished from it by the fine I'ugulosities on the elytra. From C. crassus and allies the greater extent of dark colour on the undersurface readily distinguish it. I have seen only a pair of the species. Celebes, (A. R. Wallace). 1097 1167. Cybister rugosus, Macleay, Tragus ruyosus, M.C. — Ovalis, parum latus, nigricans, capite anterius prothoraceque ad latera testaceis, elytris vitta intramar- ginali, versus apicem hamata, testacea, pectore utrinque pallido, abdomine segmeutis 3-5 ad latera testaceo-maculatis; pedibus quatuor anterioribus testaceis, tarsis intermediis piceis ; femoribus posterioribus ad apicem rufis ; elytris versus apicem profunde coriaceo-rugulosis. Long. 29, lat. 16 m.m. The male front tarsi are rather large, attaining 3 m.m. in the transverse direction ; the intermediate feet have a large patch of short sexual pubescence on each of the two basal joints. The female characters are very variable : usually that sex has a highly developed sexual sculpture, the thorax being covered with irregular scratches and the elytra bearing coarse, elongate ones, which extend four-fifths of the way to the apex, but leave the suture bear except at the base ; in certain speci- mens the elytra are entirely covered with scratches except on a minute space at the 746 On Aquatic Carnivorous Coleoptera or Dytiscidce. extremity ; on the other hand some females are quite without sexual sculpture, resembling exactly in this respect the males ; the females with highly developed sculpture have also a distinct, though not great, torsion of the epipleurae, and even in the smooth females a very slight departure from the male structure in this respect may be observed ; intermediate specimens between these forms occur. The species also varies a good deal in size and form, and also somewhat in the extent of the pale colour on the breast, and also somewhat in the depth of the rugulosities on the elytra ; the oedeagus varies very little however even in the most different individuals. The .species is readily distinguished by the peculiar roughness on the elytra ; this character cannot however be seen in the case of such females as have the elytra quite covered with sexual sculpture ; the extent of pale colour on each side of the breast is always less than in the allied species with which it might be con- founded. Widely distributed in the Malay peninsula and archipelago. Siani, Penang, Cambodia, Malacca, Sumatra, Borneo, Java. 1098. 1168. Cybister (Trogus) godeffroyi, Wehncke, Stet. Ent. Zeit. XXXVII, p. 357. — Ovalis, latus, anterius fortiter angustatus, parum convexus, nitidus, niger, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali, ad apicem obsoletescente, testacea ; pedibus quatuor anterioribus testaceis, intermediis tibiis piceo-testaceis, tarsis nigris, pedibus posterioribus nigris, geniculo superne rufescente. Long. 34, lat. 192 m.m. In the male the front tarsi are not large, scarcely attaining 3 m.m. in the trans- verse direction ; the intermediate feet have large patches of short sexual pubescence on each of the two basal joints, and there is generally a very slight line of such pubescence on the following joint, their claws are unequal but rather .short in com- parison with the allied species. The female is without sexual development ; the upper surface being quite smooth as in the male, and the epipleurae simple. The species cannot be easily mistaken for any other, it is rather larger and broader than D. rceselii (No. 1169), and quite as similar at first sight to it as to D. limbatus (No. 1157) ; from this latter it can be easily distinguished by the yellow band of the elytra being indefinite at the termination ; from D. rceselii the colour of the undersurface distinguishes it at a glance. The structure of the oedeagus is peculiar, and shows the species is really an isolated one. Australia, (Cape "iork, Eockhampton, Clarence Kiver). 1099. On Aquatic (xirnivorous Coleoptera or Dytiscidos. 747 Group 6. 1169. Dytiscus rceselii, Fab., Tragus virens, 31. C. — Ovalis, postei'ius conspicue latior, supra olivaceus, capite anterius prothoraceque lateribus testaceis, elytris vitta lateral! versus apicem attenuata, et a margine laterali separata, testacea ; corpore subtus testaceo, pectore in medio plus minusve brunneo, tarsis iutermediis et tibiis tarsisque posterioribus piceis ; femoribus posterioribus angulo externo acuto, subspinoso. Long. 34, lat. 18j m.m. The male has the daws on the intermediate feet a good deal longer than in the female, and unequal, the front one being much thicker and a little longer than tlie other; it has the uppersurfaee of the body smooth and shining, while in the female the thorax is covered with curved irregular depressions or scratches, and the wing-cases bear longitudinal scratches which anastomose here and there, a space at the apex remains, however, always smooth. On the undersurface the epipleurse of the female are conspicuously flattened just behind the shoulder, while at the same spot they are rounded in the male. In this species the yellow band of the elytra at the shoulder starts from quite the outer margin, but becomes thinner towards the extremity, and is in a gradual manner more and more separated from the outer margin,itbecomes quite obsolete be- fore the apex, but at the apex the external margin is itself vaguely yellow, and the ex- tremity of the yellow band is only separated in a very vague manner from this terminal yellow colour. The colour of the undersurface varies somewhat, the infuscation of the breast along the middle being sometimes very slight, while at other times it is quite conspicuous, and when it is greatest the coxal processes become quite greenish or olivaceous in colour. The most remarkable variety, however, is one found in Portugal, it is of small size, being about 31 m.m. long, and the sexual characters differ remarkably from what is usual in the species, the female being quite smooth on the uppersurfaee, and the anterior tarsi of the male are unusually small, attain- ing only 21 m.m. in the transverse direction, the normal dimension being 3i m.m. This variety may be designated as var. lusitanicus, I have seen only three individuals of it, two females and one male found by d'Oliveira, it is worthy of remark that the intermediate tarsus on the left leg of the male is like that of a female, while the right foot is normal. The species does not extend its range to Britain or Scandinavia. The smooth variety of the female seems very rare, the only specimens T have seen of it come from Portugal. Cybister chaudoiri, Hoch., was founded on two females found at Lenkoran, and from the description and remarks of its describer it seems highly probable that it is a variety of Dytiscus rceselii. Europe and Northern Africa. Northern France, Belgium, Germany, Portugal, Corsica, Italy, Greece, Corfu, Siberia, (East India ?) TKANS ROY. DUB. SOC, M.S., VOL. n. 8 D 74S On Aquatic Carnivorous Coleopteni or DytiscidcB. 1170. Cybister ponticus, n. sp. — Ovalis, latus, posterius conspicue latior, supra olivaceus, capite anterius prothoraceque lateribus testaceis, elytris vitta lateral!, fere ad apicem producta sed ibidem parum discreta, testacea; corpora subtus testaceo, tarsis intermediis, tibiis tarsisque posterioribus piceis; femoribus posterioribus angulo externo acuto. Long. 37, lat. 21 m.m. I have seen only a single individual of this form, and although it is quite without sexual sculpture, I think it ruay prove to be only a local race of Dytiscus rceselii ; it is however considerably larger, and has the hind legs thicker, and the marginal band of the elytra remains broader and more distinct at the extremity ; the epipleurae of the elytra are rather broader, but the sexual flattening is scarcely so conspicuous as ill Dytiscus rceselii. I am not acquainted with Cybister jordanis, Reiche {vide No. 1279), which is said scarcely to differ from Dytiscus rceselii, except by the female being quite smooth. I have seen from Northern Persia, two females which may be pei'haps but little different from this Jordan form ; they have the upper surface quite free from sculpture, and differ from Cybister ponticus in being considerably smaller, and of narrower and more parallel form, the swimming legs are more slender and the sexual flattening of the epipleurse is less : these two specimens were found by the Marquis Doria in Northern Persia in 1862-3. Whether these forms with smooth females, viz., lusit- anicus, jordanis, ponticus, are really closely allied but distinct species, or are only races occurring at the extreme geographical limits of the distribution of Dytiscus rceselii is a very difficult question which I am quite unable to answer. Mesopotamia, (Millingen). 1048. 1171. Cybister japonicus, Sharp, Tr. Ent. Soc. Lond. 1873, p. ib. — Robustus, supra sat convexus, ovalis, posterius latior, supra olivaceo-niger, capite anterius prothoraceque lateribus testaceis, elytris vitta laterali sat lata, apicem fere attingente sed ibidem parum discreta, testacea; corpore subtus variegato, testaceo, prosteriii processu pectoreque in medio olivaceo-nigris, abdominis coxarumque posticarum suturis nigris ; pedibus testaceis, tarsis intermediis, tibiis tarsisque posterioribus piceis, femoribus posterioribus versus basin plus minusve picescentibus ; femoribus posterioribus angulo externo acuto. Long. 35, lat. 19? m.m. This species is closely allied to Dytiscus rceselii, and possesses in each sex the same sexual characters as that species, but it is considerably larger, and has the yellow band on the sides of the elytra broader, and less distinctly separated from the lateral margin, and has the undersurface very distinctly variegated : the female has the flattened portion of the epipleurse broader : it is also rather different in form, being less narrowed in front, and it has the hinder tarsi longer. Japan, Formosa, Mantchuria, China, (Shanghai). 1049. On Aquatic Carnivorous Coleoptera or Di/tiscidce. 749 APPENDIX DESCRIPTIONS NOT IDENTIFIED WITH SPECIES KNOWN TO THE AUTHOR. In this appendix I have collected together all such descriptions of species of Dytiscidge as I have been unable to indentify certainly with any species known to me. Some of these descriptions can never be surely recognised except by the aid of authenticated specimens. A certain number are moreover probably identical with species described by other authors under different names ; where such indentifi- cation is probable but not certain I have not felt justified in assigning the names to the list of synonyms, and the descriptions are consequently here reprinted. Most of the descriptions are given in full, but in some cases only the diagnoses are reproduced. Where I could make any guess of importance as to the position and characters of a species I have ajipended a brief suggestion after the description. For convenience of reference these descriptions are numbered consecutively, the numbers being a continuation of those used in my own preceding species-descrip- tions, in order to avoid repetition of numbers and consequent confusion : thus they commence with No. 1172. 1172. Acilius cinctatus, Aube, spec. p. 151. Mexico. " Ovalis vix ellipticus, convexiusculus, supra niger, infra nigi-o-piceus ; thorace nigro, ad latera luteo ; elytris nigris, vitta longitudinali postice abbreviata ad marginem punctisque minimis ad apicem luteo- notatis. Long. 9^, larg. 5^ mUl." [Followed hy a description.~\ " Je n'ai vu qu'un seal individu male de cette espece ; il appartient a ]\I. Gory, qui I'a re^u de M. Klug comme venant du Mexique. " This is placed by Aube next to Acilius margineguttatus (No. 1070), to which it is apparently similar. — D. S. 1173. Acilius Isevisulcatus, Motcli., Bull. Mosc. 1845, I. p. 30. Crimea. " Acilius laevisulcatus m. de la Crimea a les sillons sur les elytres lisses comme I'Ac. semisulcatus, Dej. de Sitka, mais il est plus grand. " I do not think this can be accepted as a description ; I anticipate moreover that it is probably only Dytiscus sulcatus (No. 1052).— D. S. 1174. Acilius laporti, Aube, spec. p. 139. Brazil. " Oblongo-ovalis, convexiusculus, supra nigro-cinereus, infra ferrugineo-testaceus ; thorace ad latera et 5 D 2 750 On Aquatic Carnivorous Colcoj^itera or DtjtiscidcB. transversim in medio luteo ; elytris nigris, inaculis luinimis in-egulariter rotundatis imdique luteo-omatis, et fascia nigra confusissima ulti-a medium transversim notatis. Long. 12 m.m., larg. 6| m.m. " [Succeeded hy a description.] A single individual in the collection of Castlenau, who received it fi-om Brazil. The species is probably closely allied to A ornaticollis (No. 1059). — D. S. 1175. Acilius laticinctus, Lee, Ann. Lye. V. p. 203. North America. " Fere ellipticus minus convexus, ferrugineus, supra nigro-piceus nitidus, thorace latitudine triple breviore, lateribus late fasciaque transversa angiista luteis, elj^tris margine lato nigro-irrorato, fascia subbasali, (sKpius interrupta) apiceque luteis, ore, epistomato, macula vertical! transversa, pedibusque anterioribus flavo testaceis. Long. 45. Femina, thoracis lateribus rugosis, elytris vereus basin striolis a]iproximatis strigosis. Ad flumen Colorado, et Vallecitas frequens. A. inciso simUis." A male individual of this species recently communicated to me by Dr. Leconte seems to be structurally very closely allied to Dytiscus basUaris (No. 1071); and it must remain at pi-esent an open question whether it be a distinct species ; if not it is at any rate the most extreme variation I have seen of D. basilaris. — D. S. 1176. AcLLius maculatus, Aubd, spec. p. 141. Mexico. " Ovalis, paulo ellipticus, convexiusculus, supra nigro-cinereus, infra testaceus, thorace luteo, antice et postice in medio nigro ; elytris luteis, punctis minimis confluentibus, fascia transversa ultra medium, maculaque ad apicem confuse nigro-omatis." " Mas : elytris hevibus. Femina : ad basin lineolia brevissimis punctiformibus impressis ; thorace loevi. Long. 12 — 12^ m.m., larg. 7 — 7i m.m." [A description follows. I.e., the ahove.^ Tliis is placed by Aub6 near A. ornaticollis (No. 1059), to which it is probably similar. — D, S. 1177. Acilius subirapressus, Motsch., Bull Mosc, 1845, I. p. 30. Kamtschatka. " Acilius subimpressus m. du Kamtschatka, ressemble aussi a I'esp^ce de Sitka, mais il s'en distingue par les couleurs du dessous du corps." I do not think the above can be considered a " description," however wide be the extension anyone may be inclined to claim for that term. — D. S. 1178. AcUius tomentosus, Motsch., Bull. Mosc, 1845, I. ]). 30. Russia. " Acilius tomentosus, m. C'est une esp6ce des environs de St. Petersbourg qui ressemble beaucoup a, lA. sulcatus L., mais qui est constamment plus petite." These few words do not constitute a description, and are moreover perfectly applicable to the well known European Dytiscus fasciatus, (No. 1053). — D. S. 1179. Agabus amosnus, Solsk., Fedt. Turk., II, 5. p. 142, Urgut. Turkestan. " Ovalis, apice utrinque subacuminato-rotundatus, subconvexus, glaber, nitidus ; piceo-niger, ore, antennis, vertice maculis duabus, pedibus segm enter umque abdomiualium marginibus ferrugineis, pedi- bus posticis fusco-maculatis ; capite thoraceque nigro-seneis, virescentibus, hoc lateribus late testaceis ; elytris fusco-testaceis, basi lateribusque dilutioribus." On Aquatic Carnivorous Coleoptera or DijtisoidcB'. 751 " Mas : tarsis anticis dilatatis, compressis, subtus longe pilosis, unguiculo interno latioie et crassiore, basi subtus obtuse dentato. Loug. 10 (tbor. 2, elytra 7|), lat. elytra 5| m.ni." This is followed, I. c, by a description in Russian. The species is apparently peculiar in its colouration. — D. S. 1180. Agabus atratus, Mann., Bull. Mosc, 1853, III, p. 157. Russian If orth America. '• Oblongo-ovalis, aterrimus, opacus, striis anastomozantibus subtilissime recticulato-strigosus ; ore, antennis, capite antice, epipleuris, segmentorum ventralium marginibus, tibiis tarsisque quatuor anterioribus obscure rufis ; elytrorum lateribus disco parum dilutioribus ; pedibus posticis piceis. Longit. 5 lin., latit. 2| lin." This is omitted in Crotch's " Revision of the North American Dytiscidae." — T>. S. 1181. Agabus bakewelli, Clk., Journ. Ent. II, p. 19. Australia. " Ovalis, subtilissime reticulosus ; striato-punctatus, niger, nitidus ; capite impunctato, inter oculos undique foveolato, nigro, ore mentoque rufis ; thorace autice emarginato, lateribus rotundatis, tenue marginatis, basi sinuato, antice ad luarginem punctis transverse notato : elytris punctorum seriebus duabus subtiliter uotatis, ad latera infra medium obscure rufo maculatis ; pedibus antennisque rufis, corpore subtus fusco-rufo. Long. corp. .3 lin., lat. \^ lin." '•■ A. bakewelli resembles in size and appearance A. affinis, Payk.; it is (besides other differences) more ovate and less parallel : it is probable that in some examples the subcircular rufous marking near the margin of the elytra may be obsolete." This should no doubt be refered to the genns Platynectes. — D. S. 1182. Agabus confertus, Lee, Proc. Ac. Phil. 1861. p. 340. California. " Ovalis, modice convexus, oeneo-uiger, nitidus, dense punctulatus, baud reticulatus, thorace minus fortiter marginato, latitudine fere triplo breviore, elytris lineola laterali guttaque postica pallidas ornatis, seriebus punctorum solitis distinctis, antennis ore pedibusque anticis pioeo-nifis. Long. -32. Cabo de los Reyes." \^A comparison with A. semivittatus, Lee, follows the above dia(/nosis.'\ I have i-ecently received for examination an individual of this species and find it difficult to locate in any of the groups proposed by roe; it seems in fact to be between group 12, and group 19 ; it has the approximate middle coxre of the former grouj), but its thorax is less rounded at the sides and less discon- tinuous with the outline of the elytra, and the anterior portions of the coxal lines are fine, and although much divergent, are but little prolonged in the outward direction. — D. S. 1183. Agabus dilatatus, Sol., Gay, Hist. Chil. IV, p. 277. Chili. " A. fuscus, margine et capite ochraceiis, postice dilatatus et obtusus, ovatus supvaque obsoletissime punctulatus; protborace medio transverse confuse ochraceo-fasciato ; elytris fuscis luteo-subreticulatis, striis tribus laxe punctatis, obsoletis ; palpis, labro antennisque luteo-pallidis ; pedibus obacuris. Long. 4 lin. •^ ; lat. 2 lin. J. Habita tambien in la republica." 1 am doubtful to what genus this should be referred ; in the Munich catalogue it is recorded under Agabus, but the trivial name dilatatus is replaced by that of valdiviensis. — D. S. 1184. Agabus eminens, Kirsch, Berl. Ent. Zeit. XVIT, p. 131. Peru. " Ovalis, nitidus, brunneus, prothoracis lateribus elytrorumque macula magna basali, humenim et 752 On Aquatic Carnivonnts Coleopfcra or Di/tiscidcp. scutellum non attingente, luteis; prothorace intra latera impresso, subtilissime coriaceo, versus latera punctulato ; elyti-is seriebus 4 pnnctulatis. Long. 5 J, lat. 3 mill. " The description which follows this diagnosis, I. c, leaves it doubtful to what genus this should bo referred. — D. S. 1185. Agabus foveolatus, Muls., Op. Ent. XI, p. 177. France. " Oblongo-ovalis, vix convexus, j)0stice depressiusculus, subtilissime punctulato-substrigosus, subtus nitidus, supra subopacus, niger ; thoracis disco leviter bifoveolato ; elj^tris fuscis, extrorsum gradatim fusco-fermgineis, margine inferiori ferrugineo ; antennis pedibusque ferrugineis, femoribusnigris. Long. 0,0072 (3J 1.)— Larg. 0,00G1 (2f 1.)." " Elle se rapproche des A. uliginosus et congener. Elle diSere de I'un ct de I'autre par I'abseuce de tacbes rouges sur le vertex ; elle s'eloigne du jiremiei-, par son prothorax noir, excepts le rebord marginal, par ses cuisses noires : du second, par toutes ses cuisses noires : de tous les deux par les deux petites fossettes du disque de .son prothorax. " Found in the Basses Alpes at 2,000 metres of elevation. 1186. Agabus fuscosenescens, Hegt., Ann. Soc. Ent. Fr. (v) VII, p. CXLVIII. Austria. " A. sturaii, Gyll. sat affinis: \-ix convexus, subtiliter reticulatus, nitidus, fusco-niger, vix senescens, ad prothoracis elytrorumque latera vage rufescens, subtus niger, cum abdominis segmentis postice vix ferru- gineo-limbatis ; antennis crassiusculis, omnino testaceis ; capite maculis duabus ferrugineis postice et circa clypeum antice notato. Mas, abdominis ultimo segmento post dimidium punctato-strigoso, et unguiculis anticis aqualibus, simplici>)us et valde incurvatis dLstiuctus. Long. 9 J a 1 0 mill. " \^A comparison with several other species follows this deseription.^ 1187. Agabus glacialis, Hoch., Chaud. Euum. Car. p. 218. Caucasus. " Elongato-ovatvis, subdepressus, nitidus, nigro-piceus, ore, cum palpis, capite antice, thoracis elytro- rumque margine inflexo, segmentorum abdominalium summis marginibus, tibiis tarsisque late ferrugineis ; thoracis lateribus subrectis ; elytrorum punctis majoribus posterius irregulariter sparsis, anterius in series ternas digestis." " Mas : el3rtris nitidioribus, obsolete reticulatis, punctis distinctius impressis." " Femiiia : elytris opacis, evidentius reticulatis, punctis minoribus." " Variati. : pedibus anticis totis ferrugineis. Long. 3 lignes." " M. de Chaudoir a trouve cette espece pres du sommet des montagues d'Abbastouman, a 7,000 pieds environ d'elevation, sous les pierres au bord des ruisseaux qui decoulent des amas de neige. (Juin)." This species probably will go into my second group near Agabus armeniacus (No. 671 ) ; the description does not agree with the colour of that species. — D. S. 11S8. Agabus Goryi, Aube, Ic. V, p. 162, pi. 20, f 1. Spec. ]). 337. Asia Minor. " Oblongo-ovalis, supra castaneo-brunneus, infra niger ; el_\-tris macula paulo ultra medium ad latera alteraque minima ad apicem paUido luteo-notatis ; pedibus nigro-fen-ugineis. Long. 8 a 9 m.m., larg. 4^ — 4J m.m." [.4 descrijition follows.] Found at Smyrna by M. Carcel. In the Munich Catalogue this is recorded as a variety of Agabus dilatatus, Br., (Col. dilatatus, No. 1220, huj. op.), but it is doubtful whether this be coi-rect.^D. S. On Aquatic Carnivorous Coleoptera or DytiscldcB. 753 1189. Agabus gougeleti, Reicbe, Ann. Soc. Fr. 1863, p. 474. Corsica. " Ovalis, parum convexus, atro-piceus, nitidus. Caput ooriaceum, ante oculos utrinque transversiin impressum ; antennis palpisque rufo-testaceis, his apice piceis. Thorax caj)ite fere duplo latior, latitudine plus dimidio brevier, antice profunde emarginatus ; angulis acutiusculis ; a latere paulo rotundatus, postice parum sLnuatus ; auguUs rectis, acutiusculis ; disco coriaceo, antice transversim punctato-impresso, a latere late rufo-testaceo, basi medio loevigato utrinque linea transversal! punctata instructo. Scutellum piceum, coriaceum. Elytra thoracis basi latitudine, iude ad medium parum dilatata, ultra medium attenuata, apice conjunctim rotundato-acuminato, triseriatim punctata ; punctis piligeris ; fusca ; basi et ad latera vage testaceo-maculata, paido infra medium macula albida translucida laterali indeterminata et inde ad apicem maculis similibus minoribus nonnullis sparsis. Subtus niger, pedibus rufescentibus, feuioribus basi nigris. Mas etfem. Long. 8 J, lat. 4^ m.m." I cannot from the description identify this species with any certainty; the specimens I have seen in collections under the name are a variety of Dytiscus conspersus (No. 714). — D. S. 1190. Agabus htera or Dytiscidce. 1215. Colymbetes bicolor, Kii'b., Faun. bor. Am. TV, p. 70. North America. " Ater, ellipticus, convexus, nitldus, ore antennisque testaceis ; pedibus elytrisque latere extemo, brunneis ; prothoracis serie postico continuo. Length of the body, 3 J lines. A single specimen in lat. 54°." The Munich Catalogue refers this to the genus Agabus. — D. S. 1216. Colymbetes bimaculatus, Perroud, Ann. Soc. Lui. Lyon. XI, 18G4, p. 78. New Caledonia. " Elongato-ovalis, depressiusculus, levis, nitiJus, fusco-brunneus. Capite antice posticeque rufo, antennis testaceLs. Prothorace lateribus paulo oblique rotundatis, rufo-brunneo, antice transversim pimctato. Scutello triangiilari. Elytris subtiliter striato-punctatis, brunneis, postice lateribus flavo limbatis et singiilatim ad basin macula transversaH flava uotatis. Corpore subtus pedibusque testaceis. Long. 0,004m. ; larg. 0,001 ^m." " Cette petite espfece prise par M. IVl ontrouzier, a Jengeu, dans la Nouvelle Caledonie a quelque resemblance a premiere vue avec I'Hydroporus sex-pustulatus." Probably a Copelatus to be placed in my group I. — D. S. 1217. Colymbetes clairvillei, Mont., Ann. Soc. Fr. 1860, p. 242. New Caledonia. "Long. 15 m.m. ; larg. 8 m.m. ; epaiss. 4 m.m. Minor, niger, capite duplicizona luteo-rubro ornato. Thorace transverso, anterius et in medio limbi nigro, alias luteo-rubro, la^vi. Scutello conspicuo, trian- gulari, Isevi. Elytris ovatis, convexis, l!B^^bus, nigris, margine tribusque zonis, quarum duae posteriores interruptse, luteis." " La couleur gen^rale du corps est d'lin noir vernisse. La tete est d'un jaune rouge avec une large bande vineuse noire en travers." The colour would seem to point this out as a species of Sandracottus. In the Munich Catalogue it is recorded in the genus Agabus, but this is no doubt an error. — D. S. 1218. Colymbetes costulatus, Motsch., Bull. Ac. Pet. 1859, p. 541. Siberia. " Oblongo-ovalis, dense scarLficatus, nitidus, niger, elytris vix distincte costulatis, fuscis, margine dilutiore ; palpis, antennis, tibiis tai-sisque rufis. Long. 3^ 1. lat. 1^ 1." " Plus allonge et plus large vers la tete que notre Col. Sturmii ; elytres plus ctroites et plus ou moins rembrunies, avec deux lignes de points imprimes sur le milieu et quelques autres epars et irregulierement places vers les bords." It is probable that this description indicates a species of Agabus. — D. S. 1219. Colymbetes darwimi, Bab., Tr. Ent. Soc, 1841, p. 8. Patagonia. " Ovatus, supra flavescens, subtus niger vel nigro-fuscus, vertice nigro, macula transversa flava, thorace antice et postice maculaque disci nigris ; elytris plus minusve crebre nigro-irroratis, striisque disci punctatis, antennis flavis pedibus flavis vel fuscescentibus. L. 5 — 6, lat. 2| — 3 lin." Tierra del Fuego. " Ovate, flavesceut, fusco flavescent, or fuscous. Crown of tlie head black, with a transver.se flavesceut spot, which is connected by its middle with the anterior concolorous part of the head, so as to form a T shaped mark. Antennse yellow. Thorax margined before and behind more or less broadly with black and an ovate transverse spot of the same colour on the disc. Scutellum black. Elytra ovate, dilated slightly beyond the middle, flavescent or fuscous yellow, thickly irrorated with black, in some specimens so thickly as to make the whole appear fuscous black ; the usual strife rather strongly marked, and formed of irregular punctm-es. Body l)eneath black, or fuscous black. Legs dark yellow or fuscous." On Aquatic Carnivorous Coleoptera or DytiscidoB. 759 " Extremely variable in colour ; some specimens being nearly black, and others quite pale." This appears to be a species of Rhantus very near Dytiscus signatus, No. 926, if not actually the same thereas. — D. S. 1220. Colymbetes dilatatus, Brulle, Exp. Mor. Ent. Ill, p. 127. Europe. " Kolar. ined. — Fuscus, levigatus, depressus ; capite maoulis 3 piceis ; elytris levissime seriato-punctatis, maculis 2 pone medium pallida croceis ; corpora subtus cum femoribus posticis atro ; pedibus oreque at antennis piceis. Long. 9 millim.,lat. 5. — (Voyez notra PL XXXIV, fig. 11.)" Descr. Tout le dessus de I'insecte est brun, at tres-finement guilloche ; la teta marquee de trois taches rougeatres, savoir une vers le bord anterieur, de forme irr^guliere et plutot transversale, de couleur fonc^e, et deux autres sur le bord posterieur, plus claires et arrondies ; antennes enti^rament rougeatres, ainsi que las palpes. Corselet court, transversal, legerement sinue an avant et en arri^re ; ses angles anterieurs pointus et avances, les posterieurs carres : outra un commencemeut de sillon longitudinal, on distingue pres des bords anterieurs et posterieurs un sillon transversal dans toute la largeur du corselet ; en arri^re ce sillon sa termine par des points enfoucfes, places a distances in^gales. Ecusson en triangle ^Lirgi. Elytres un peu plus larges que la base du corselet, aplaties, ovalaii-es, marquees de quelques series de points enforces peu profondes et ecartes ; un peu plus bas que le millieu des elytres, sur le bord lateral, on remarque ime tacbe d'un jaune obscur de forme irreguli^re : a partir de cette tache jusqu' a la base, le bord est un peu rougeatre. Tout le dessons du corps est noir, ainsi que les deux cuisses posterieures ; jambes et tarsesde cette pa-'re de pattes et les deux paires precedentes rougeatres." " Hab. Dans les eaux stagnantes des marecages, qui se dessechent vers la fin de la belle saison. Commxmique par M. de Laporte." It was suggested by Aube (Spec. p. 341) that this may possibly be a variety of Dytiscus guttatus (No. 670) ; this remains stUl uncertain, and it is not quite clear to me that Aube had really Brull6's species before him when he supposed he was describing it (I. c.) — D. S. 1221. Colymbetes discicollis, Aube, Spec. p. 250. Java. " Ovatus, supra flavicans, infra niger ; thorace disco nigricante ; elytris crebre nigro-irroratis ; prosterno pallido. Long. 10 m.m. larg. 5 m.m. " [This is followed by a description.] I think this may pi-obably prove to be only Colymbetes pulverosus No. 924. — D. S. 1222. Colymbetes discolor, Harris, New Farm. 1828, p. 164. " Black, minutely and obsoletely granulated. Head with two basal piceous spots ; elytra fuscous, margin and base pale, epipleura yellowish ; three series of setiferous punctures, which are obsolete behind, on each elytron : ventral segments at tip and feet piceous : nails alike in both sexes. Length over three- tenths of an inch. " " Specimens five. Appears to diSer from all of the species described by W. Say. " . This is perhaps an Agabus, but the species to which the description is intended to apply will not be recognised with any certainty. The name is not alluded to by Crotch, who however has changed the name of Agabus discolor, Lee, for that of Gaurodytes lacontei, I presume on account of the existence of this name of Harris'. — D. S. 1223. Colymbetes distigma, Brulle, Voy. d'Orb. Col. p. 48.— Aube Spec. p. 222. South America. " Niger, opacus, punctis minimis raris oninino tectus ; macula in vertice et altera ad marginem elytro- rum paullo ultra medium rubro-feiTugineis. Fern. Long. 14 m.m. larg. 7 m.m. " Aube, /. c. [The above is followed by a description.'] Found by D'Orbigny in the Cordilleras. I cannot even form an idea as to what genus of the Colymbetides this will prove to beamember of — D. S. 760 On Aquatic Carnivorous Coleoptera or DytiscidcB. 1224. Colymbetes drewseni, Lee, Proc. Ac. Phil. 1862. p. 523. Greenland. " Elongate oval ; thorax feebly punctured towards the base, with scarcely perceptible rugosities ; lines of elytra deej), moderately approximate ; legs pale brown, thighs darker. Fern. 60.'' " Sides of thorax strongly rounded, sinuate near the anterior angles, which are strongly acuminate." The sides of the thorax are peculiarly rounded and sinuate at the front angles (in the male), but it is jiossible that the insect is an abnormal form of 0. groenlandicus (No. 967). — D. S. 1225. Colymbetes duponti, Aube, spec. p. 260. S. America. " Oblongo-ovalis, niger, capite cum labro, epistomo, maculaque transversa in vertice rufo-luteis ; thoracis lateribus rufo-luteis ; elytrorum margine et apice luteis, crebre nigro-irroratis ; pedibns nigria femoribus anticis et intermediis apice rufo-ferrugineis. Long. 11 m.m., larg. 6 m.m." [^This diagnosis is followed, I.e., hy a description.] This is probably near Dytiscus signatus, No. 926. — D. S. 1226. Colymbetes fonticola, Phil, Stett. Ent. Zeit., 1860, p. 2i7. Chili. " Oblongo-ovatus, postice dilatatus, supra pallide ochraceus, subtus niger ; capite prope oculos utrinque punctis 2 aut 3 impresso, nigro, punctis 3 orbicularibus, duobus prope basim, altero in medio, maculaque triangulari in epistomo aliquando cum puncto anteriore juncto pallide ochraceis ; tergo prothoracis lineis punctorum in margine antico lateribusque impresso, et in medio macula transversali, trapeziformi, obscura, notato ; elytris valde et dense nigro-punctatis, punctis in sutura et margine oblitteratis, utroque elytro lineis tribus longitudinalibus punctorum rare positorum impressis ; femoribus anticis obscure ochraceis, mediis et posticis nigris, apice fuscis ; tibiis tarsisque obscure fuscis ; antennis palpisque testaceis. Long. 6g"', lat. 3'"." " Valdivia in rivulis." This would appear to be a species of Rhantus very near Dytiscus signatus (No. 926). — D. S. 1227. Colymbetes fossiger, Motsch., Bull. Mosc. 1859, III, p. 170. California. " Oblongo-ovatus, depressiusculus, reticulatus, subnitidus, nigro-subi«neus, elytris fuscis, ore, palpis, antennis pedibusque rufesoentibus ; capite triangulare, antice subtruneato, subtUissime reticulato, quadri- impresso ; thorace transverse, basi ai-cuato, utriuque subsinuato, lateribus marginatis, arcuatis, angulis anticis prominulis, posticis subrectis, elytris oblongo-ovatis, postice fei'e obtusis, striis punctorum indis- tinctis. Long. 3 j 1. lat If 1. San Francisco." " Cette espfece ressemble assez a notre C congener, dont il a aussi la taille, mais sa forme est moins obtuse et ])lus regulifirement ellij)tique. La tete est triangulaii-e tronquee en avant avec quatre impressions sur le front, dont deux en avant, en forme de fovfeoles, et deux autres plus rapprochies, tres jjeu profondes et placees plus au dessus et entre les yeux : on voit en outre sur le vertex deux taches arrondies roussatres, peu distinctes. Le corselet est plus large que la tete, assez fortement arrondi sur les cotes, avec la ponctua- tion marginale peu pi'ononcee et confondue avec la reticulation de la surface, qui est beacoup plus forte que sur la tete ; les impressions laterales de la base sont bien marquees ainsi qu'une ligne foveiforme longitudinale sur le milieu. L'ecusson est de couleur plus testace que les elytres ; celles-ci ont leur base de la largeur du corselet, et ensuite regulierement ovalaii-es jusqu' a I'extremit^ ayant la partie la plus large vers le milieu ; la reticulation est aussi forte que sur le corselet ; I'angle humeral, une tache laterale au milieu et la marge vers I'extremite, ainsi que les epipleures paraissent un peu plus claires que le reste des elytres." This is evidently a species of Agabus. — D.S. On Aquatic Carnivorous Coleoptera or Dytiscidce. 761 1228. Colymbetes (Ilybius) fraterculus, Lee, Proc. Ac. Phil. 1862, p. 521. North America. " Base of thorax broadly rounded ; brownish-black, slightly bronzed, oval, slightly dilated at the middle, not less obtuse behind ; thorax with the sides nearly sti'aight ; elytra with the anterior pale spot very small, the hind one wanting ; lines of punctures visible only behind the middle. 42. North Eed Eiver." 1229. Colymbetes goedeli. Villa, Col. Eur. dupl. 1833, p. 33. Italy. " Ovatus, niger, subdepressus ; pedibus elytrisque piceis ; thoracis elytrorumque margine exteriore Have." TJiis may I think be allowed to be forgotten in future. — D. S. 1230. Colymbetes gutticollis. Say, Ti-. Am. Phil. Soc. IV, p. 442. Mexico. " Thorax yellowish with four black spots ; head black, anteriorly and band of vertex yellow. Head black ; a transverse yellowish band between the nearest points of the eyes ; a dilated yellowish triangle occupying all the anterior part of the head, tlie apex being at the middle of the face ; antennae and palpi honey-yellow, dusky at theii- tips; thorax honey-yellow, anterior margin blackish; posterior margin dusky ; four large black spots in a transverse series, the two intermediate ones nearer together ; elytra honey-yellow with minute black points more or less crowded so as to give a dusky, sometimes almost blackish appearance ; lateral margin destitute of black punctures, but with a black line on the posterior curvature ; at base, particularly the humeral base, destitute of the black punctures ; three regular series of small black dots ; beneath black ; pectus, feet and epipleurse yellowish. Length, over two-fifths of an inch." " Taken in the river beyond Vera Cruz." "It is about the size of the C adspersus, Fab., which it considerably resembles if we except the thoracic black dots." This is probably near if not actually identical with C. binotatus (No. 935) ; the description in several points does not apply to that species very well. — D. S. 1231. Colymbetes impressus, Zubk., Bull. Mosc, VI, 1833, p. 317. Turcomania. " Long. 3 lig., larg. 1^ lig. II est brim avec les bords de la tete, du corselet et dea elytres un peu ferru- gineux. Le corselet a une impression bien marquee au milieu, pr^s du bord posterieur. Les Elytres paraissent lisses, mais avec une forte loupe on voit qu'ils sont couvex-ts de petits points tres rapproch^s. Chaque elytre a le long de la suture une serie de points enfonces, rapproch6s, inegaux. Le dessous du corps est noir ; les pieds sont ferrugineux. " Turcomania." 1232. Colymbetes inaequalis, Horn, Tr. Am. Ent. Soc, 1871, p. 330. North America. " Elongate oval, broader behind the middle. Head black with vertical rufous spot, and anterior margin pale yellow, very finely and densely punctured. Thorax yellowish or brownish with median transverse band and narrow margin at middle of base black, surface intricately and confluently lined and in the intervals punctured, lines obsolete at margin which is densely and finely punctured with a few coarser punctures intermixed. Elytra brownish, sometimes paler, margin paler than disc ; surface sculptured with transverse lines more deeply graven at the basal two thirds, in which region the surface is subopaque from the intervals between the lines being scabrous ; apical third more shining. Body beneath black shining, surface finely transversely strigose, strigse becoming longitudinal at the first two abdominal segments and at the sides of the others, and at the middle of the segments the lines are nearly 762 On Aquatic Carnivorous Coleoptera or Dytiscidcc. transverse, but very distantly placed. Legs pale, femora piceous ; legs sometimes entirely black. Length, -GB-'TO inch ; 16-5-175 m.m." This species is closely allied to C. seminiger, Lee, (No. 063), but according to a female recently communicated to me, is narrower, has the legs and epipleui-se paler, and the sculpture of the thorax and elytra much coarser than in the male of C. seminiger. — D. S. 1233. Colymbetes includens, "Walk., List. Col. Lord, p. 14. Arabia. " Black, elliptical, smooth, shining. Head with an interrupted transverse tawny streak in the disc ; forepart tawny, including a black spot on each side. Palpi, antennae and legs tawny. Prothorax testaceous, with two abbreviated black bands, one in the disc, the other on the hind border. Elytra with a testaceous ground hue, which is very closely covered with minute black speckles. Length of the body C lines." 1234. Colymbetes interclusus. Walk., Ann. Nat. Hist. 3rd Ser. II, 1858, p. 204. Ceylon. " Ater, capite antice, thoracis lateribus latis, elytrorum fascia lata basali et vitta marginali postice attenuata hiteo-ferrugineis. Long. 5| lin." This is I believe a sj)ecies of Rhantus unknown to me. — D. S. 1235. Colymbetes lateralis, Gebl., Nouv. Mem. Mosc. II, p. 40. Siberia. " Oblongo-ovalis, luteus, supra siibtilissime alutaceus, thorace macula apicaU elytrisque nigro-SBneis, his margine late luteo. Long. 4 lin., lat. 2 lin. Eneo-nitidus." Motscliulsky in Schreuck's Amur Reise, p. 102, assigns this species to the genus Ilybius. — D. S. 1236. Colymbetes latus, Gebl. Bull. Ac. Pet. VIII, 1841, p. 371. Siberia. " Dilatatus, niger, subtilissime coriaceus, ore, antennis, thoracis extreme mai'gine pedibusque anticis fetTugineis, thoracis lateribus longitudinaliter impressis, ruguloso-punctatis, elytris postice depressis, late rotundatis, lineis tribus subelevatis et pone illas striis tribus e punctis majoribus. Long. 4| lin., lat. 2f lin." " Valde affinis C. bipustulato; sed statura latiore et forma elytrorum differre videtur." The genus appears to me doubtful, although the comparison made is, I suppose, with a species of Agabus. — ^D. S. 1237. Colymbetes lineatus, Redt., Hugel. Casch. IV, p. 503, pi. 23, f. 5. India. " Ovalis, niger, clypeo, vertice, angulis anterioribus thoracis, antennis, palpis pedibusque anterioribus mfo-femigineis ; elytris stiiis macularibus basique pallide-testaceis. Long 3."' " " Durch seinen flachen Kbrper und vollkommene ovale Form desselben auffallend von der gewohnlichen Form der Colymbeten verschieden." I know nothing like this, and am doubtful what it should go near ; perhaps the Japanese Agabu.'i dissimilis, No. 766. — D. S. 1238. Colymbetes mageUanicus, Bab., Tr. Ent. Soc. Ill, p. 10. Patagonia. " Ovatus, niger, subdepressus, elytris subcostatis macula parva laterali oblonga fenestrata, subtus niger, antennis pedibusqiie fuscis. Long. 3, lat. H lin." " Ovate, black, verj- minutely reticulate strigose. Head immaculate. Antennae fuscous. Thorax On Aquatic Carnivorous Coleoptera or Dytiscidce. 7G3 much broader behind than in front, the hinder angles slightly acute. Scutellum black. Elytra oval, obscurely ribbed longitudinally, and having at a little beyond the middle, and near to the outer margin, a minute oblong fenestrated spot ; the usual striae scarcely distinguishable, and very irregular. Body beneath black. Legs fuscous." Hab., Tierra del Fuego. The type in the British Museum seems to be a species of Platynectes. — D. S. 1239. Colymbetes marmoratus, Perroud, Ann. Soc. Linn. Lyon., 1864, p. 77. New Caledonia. " Oblongo-ovatus, nig^r, capite in vertice bntnneo-rubro. Elytris rufo-brunneo vermiculatis, in singulis punctis triplici serie; palpis, antennis pedibusque rufo-piceis. Long. 0,012m., larg. 0,006m." " Cette espece qui se rapporte beaucoup du Colymb. calidus, Fab., a ete prise a Kanala, dans le mois da Janvier, par M. Montrouzier. Elle parait tres rare." This may possibly be a species of Hydaticus or Rhantus. — D. S. 1240. Colymbetes monostigma, Hope, Proc. Ent. Soc, 1842, pp. 39 and 47. Australia. " Ater, nitidus, elytris uno aurantio stigmate ornatis, corpore infra nigro, pedibua rufo-piceis. Long, lin. 3|, lat. lin. 2. Port Essington." This may po.ssibly prove to be a species of Platynectes. — D. S. 1241. Colymbetes obscuricollis, Aube, Spec. p. 251. Chili. " Ovatus, supra flavicans, infra niger ; thorace punctato rugose, in medio amplius nigricante ; elytris crebre nigro-irroratis ; prosterno nigi-o. Long. 10 m.m., larg. 5i m.m." \This diagnosis is followed, 1. c, by a description.^ The description seems to indicate a species very similar to D. signatus (No. 926). The type in Chevrolat's collection has I believe been nearly eaten up by Anthreni. — D. S. 1242. Colymbetes octodecimmaculatus, Macl. Ann. Jav., p. 31. Java. " Niger, capite maculis tribus, thorace marginali, elytris vitta marginal! maculisque novem flavis. Long. Corp. -^^ inch." " Caput maculis tribus mediis. Thoraceque macula marginali flavis. Elytris striis tribus punctorum obsoletissiniorum, vitta marginali nee basin nee apicem attingente, maculis flavis tribus basalibus, quatuor mediis fasciam fere formantibus et duabus apicalibus. Corpus subtus nigrum abdominis lateribus rufo-maculatis. Pedes quatuor antici flavi." This probably belongs to the genus Platynectes. — D. S. 1243. Colymbetes phseopterus, Kirby, Faun. Bor. Am. IV, p. 70. North America. " Ellipticus, subdepressus, ater, nitidus ; elytris fuscis, margine laterali dilutioribus ; ore, antennis pedibusque, ferrugineis : prothorace serie posticointerrupto." " Brown-winged Colymbetes, elliptical, subdepressed, very black, glossy ; elytra brown, externally paler, mouth, antennae, and legs ferruginous ; prothorax with the posterior series interrupted. Length of the body 31— 3^ lines." "Two .specimens taken in Lat. 54°." " Description. Body nearly elliptical, rather depressed, smooth, very black, glossy. Head withapair of transverse obscure red spots in the vertex ; mouth and antennse testaceous : posterior series of the jirothorax thickly punctured, and discontinuous in the middle ; elytra brown, a little paler at the base TRANB. HOT. DUB. SOC, N.S., VOL. II, 5 F 7G4 On Aquatic Carnivorous Coleoptcra or DytiscidcB. and side ; epipleura yellow ; sculpture of the elytra like that of C. semipunctatus, but fewer punctures in the side; legs ferruginous ; body underaeath longitudinally scratched." " This species appears to be the American representative of C. paludosus CDytiscus politus, Marsh.) which it nearly resembles, but the anterior part of the fi-ont is black, and not yeUow as in that species ; and the prothorax is wholly black, ^vithout a broad rufous margin." In the Munich Catalogue this is placed as a synonym of Colymbetes discolor, Harris (No. 1222). I do not know on what authority. — D. S. 1244. Colymbetes picipes, Kirb. Faun. Bor. Am., IV, p. 71. North America. " Ovalis supra jeneo-niger, obscurus, reticulatim confertLssime acuductus ; ore antennisque ferrugineis ; pedibus quatuor anterioribus piceis. Length. 4} lines. Near C. ater." This is possibly an Ilybius near I. ignarus, (No. 789). — D. S. 1245. Colymbetes rotundicoUis, Bab., Tr. Ent. Soc, 1841, p. 7. Patagonia. " Oblongus, thorace elytrorum basin jequanti, lateribus rotundatis, fuscis, subtus niger; elytris crebre nigro-i-eticulatis striisque disci punctatis, antennis pedibusque fuscis. L. 4, lat. 2 lin. " " Whole insect fuscous. Head nearly black on the crown, minutely punctured, with two deep fove. 132. Peru. " Oblongo-ovalis, nitidus, fusco-feri-ugineus, protlioracis latevibus elytrorumque Lasi flavidis ; piothoiace tlisco puuctulato, versus latera striolato,intra angulos posticos inipresso, medio liuea brevi ; clytris disco externo striis sex antice posticeque valde abbreviatis. Long. 5^, lat. 3^ m.m." " Langlieh-oval, nach Mnten stumpf zugespitzt ; biaunlich rostgelb, der kopf vom und am scheitel, die seiten des lialssckUdes und der breite -mirzelrand der fliigeldecken gelblich, an den hinterbeinen die scLieuen und fiisse melir riitlilicL. Das Lalsscliild von den spitzeu hinterecken an nach vom la.st geradlinig verengt, vor den hinterecken eingedriickt, die seiten durch eingedriickte punkte breit abgesetzt, auf der scheibe fein jninklirt und mit einer kurzen liingslinie versehen, nach den seiten hin mit kurzen und scharfen liingsrissen besetzt. Die iliigeldecken in der mitte der aiisseren scheibe mit 6 streifen, die vom und liinten stark abgekiirzt sind und von denen der Iste, 3te und 6te bis zur basis und spitze als feine l)unktreihen fortgesetzt sind, ausserdem auf der innern scheibe eine punktreihe. Die seiten der hinter- brust und des hinterleibs fein langsrissiof." 1263. Copelatus formosus, Woll., Col. hesp., p. 34. Cape Verde Islands. " Niger, (interdum piceo-niger), sixbnitidus ; capite prothoracisque lateribus plus minusve rufo-ferru- gineis; elytrLs eleganter arguteque simpliciter striatis, per basin iuterstitiumque (apice excepto) sublaterale, necnou in macvda parva subapicali rufo-testaceis ; autennis pedibusque rufo-testaceis. Long. corp. liu. 2J-2|-" "Hab., S. lago ; in aquis intermediis, praecipue fluentibus, rarior." This is supposed bj- the describer, /. c, to be an African species identical with one from Zululand. — D. S. 1264. Copelatus gallapagoensis, Wat., Ann. Nat. Hist. XVI, 1845. p. 23. Gallapagos Islands. " Copelatus |1) galapagoensis, Cop. ovatus, parum convexus, piceus ; capite, marginibus lateralibus thoracis et elytrorum, antennis pedibusque rufo-testaceis ; thorace disco nigi-o, punctis minutissimis Bubremotis impressis ; el)i;ris distincte sed anguste striatis. — Long. corp. 2| lin." " The Galapagos species differs from the Colymbetes elegans of Babington (■=Dytiscus posticatus No. 875, huj.op. D. S.) in being smaller and proportionately rather naiTOwer ; in having the legs of a paler hue, (these being pitchy black in C. elegans, and pale testaceous in C. galapagoensis ), and the strijB of the elytra more ])ei-fect. In C. galapagoensis the striaa are abbreviated but the second, fourth, sixth, eighth and tenth all terminate on the same line or nearly so, that line being about the posterior fourth of the el5rtron. The thorax presents extremely delicate punctures, and numerous minute longitudinal scratches, requiring a tolerable powerful lens to perceive them ; they ai-e most distinct towards the sides and hinder part of the thorax " The individual described is no doubt a female. — D. S. 1265. Copelatus normalis, Er., Wieg. Arch. 1847, I, p. 74. Peru. " Oblongo-ovatus, depressus, nitidus, piceus, cajiite, prothoracis disperse striolati lateribus pedibusque rufis, elytris fuscis, striga laterali pallida, dorso 10-striatis. Long. 3 J'"." 1266. Copelatus obtusus. Boh., Ins. Caffrar., p. 242. Caffraria. " Ovalis convexiusculus, subtiliter pimctulatus, nitidus, nigro-piceus ; antennis palpis, capite anlice ct in vertice, pedibus prothoraceque ad latera rufo-testaceis ; elytris apice obtusis, stiiis in disco sex tenuibus, interioribus versus apicem remote punctulatis, alteraquc ad marginem utrinque abbreviata, impressis. On Aquatic Carnivorous Coleoptera or DytiscidcB. 769 interstitiis planis 4 et 5 medio confertissime aciculatis, linea longitmliuali disci, margine apiceque rufo testaoeis. Long. G, lat. 3^ m.m." Caffraria orientalis. [This diagnosis is followed, 1. c, hy a long description.] 1267. Copelatus quadrisignatus, Regt., Ann. Soc. Eat. Fr. (V) VII, p. ixxviii. Manilla. " Ovalis, elongatus, depressus ; capite testaceo ; protliorace testaceo-ferrugiueo, late iu medio nigro- infuscato ; elytris nigris utrinque striis sex haud abbreviatis et septima marginali antice abbreviata im- pressis, vitta transversa ad basin alteraqiie macula obliqua ad apicem flavo-notatis ; subtus rufo-testaceiis, jiedibus concoloribus. Long. G mill." \_At p. 3-56, op. cit., a detailed description is given of this species.] 1268. Copelatus striatellus, Bob., Ins. CafFr. I, p. 243. Caffraria. " Oblongus, convexiusculus, obsolete puuctulatus, nitidus, supra nigro-piceus, subtus rufo-ferrugineus ; capite, ore, autennis protboraoeque ad latera, rufo-testaceis, boc medio infuscato ; elytris apice attenuatis, disco striis 9 tenuibus, inteiiori antice valde abbreviata, alternis 3, 5 et 7 interruptis, mox pone medium desinentibus, mai-gine laterali ultra medium latius rufo-testaceo. Long. 6, lat. 2| m.m." Caffrai-ia interior. [This diagnosis is followed, 1. c, by a detailed description^ 1269. Copelatus striaticoUis, Luc, Cast. Voy. 1857, p. 48. Soutb America. "Long. 7 mill., larg. 4 mill. II vient se placer dans le voisinage du 0. Duponti, Aub6. II est ovale allonge, legerement attenue en arriere et. a peine deprime. La tete le labre et le vei-tex sont d'un rouge ferrugineux. Les autennes sont rougeatres, ainsi que les palpes maxillaires et labiaux. Le thorax est noiratre et assez largement rougeatre sur les bords lateraux ; il est a peu pres deux fois et demie aussi large que long, assez largement eobancro en avant, tr6s legerement coupe carrement en arriere, arrondi sar lea cot^s, qui sont finement relevcs ; les angles anterieurs sont saillants et aigus, les posterieurs droits et legerement ari-ondis ; U est couvert d'un assez grand nombre de tres petites stries, courtes, liaeaires, peu serrees et trfes legerement onduleuses. Les elytres ovalaires, sont allongees, legerement attenufes en arriere et a peine deprimees ; elles sont noires avec leurs parties ant^rieures, mediane, et posterieure, rougeatres transversalement ; elles presentent sur le disque dix stries longitudinales, assez enfoncees ; ces stries naissent de la base et ne vont pas jusqu' a I'extremite ; les premiere et deuxifeme sont tres courtes ; les 4me, 8me, Gme et 9me sont moins allonges que les autres. Les pattes sont rougeatres." " Minas Geraes.". 1270. Copelatus substriatus, Kirsch, Berl. Ent. Zeit. XVII, p. 132. Peru. " Elougato-ellipticus, nitidus, subtus fusco-testaceus, supra niger, capite ferrugineo, prothoracis lateribus elytrorumque vitta marginali postica flavidis ; elytris lineis duabus discoidalibus antice dense punctulatis, postice obsoletis, remote punctulatis. Long. 6J, lat. 3 m.m." " Die fliigeldecken an den seiten selir flacb gerundet ; oben schwach gewolbt, nacb hinten flacher, mit 2 auf der vordern hJilfte deutlich eingedriickten, dicbt und selir fein punktirten linein auf der scheibe, die auf der hintern biilfte nur als Punktreihen fortgesetzt sind und einer di-itten pimktreibe niiber deu seitenrande, ausserdem auf den beiden zwischenriiumen nocb je einer reihe sehr entfernt gestellter punkte ; die beiden linien auf der scheibe entsprechen in ibrer lage derjenigen streifen, die bei manohen mehrfach gestreiften Copelatus-arten starker suid als die iibrigen ; die scheibe ist schwarz, die basis und naht trlibroth, der seitenrand nach huiten gelblich. Die seiten der hinterbrust langsstrichelig." 770 On Aquatic Carnivorous Coleoptera or DytiscidcB. 1271. Copelatus undecimstriatus, Aube, spec. p. 383. Cayenne. " Oblongo-ovalis, depressiis, brunneo-castancus ; capite et tliorace fere undique rufo-ferrugmeis ; lineolis vix conspicuis in tliorace ; elytris in disco striis undecim longitudinalibus alteraqiie ad marginem antice abbreviata utrinque impressis. Long. 4|, lat. 2| m.m." (jl description follows, I.e., the above diagnosis). " Ce Copelatus ressemble, au premier aspect, au decemstriatus, mais outre le nombre des stries des glytres qui n'est p;xs le meme, il en differe encore par la forme de son corselet qui est plus sinueux en ai-riere, la partie mediane de la base s'avancjaut un peu sur I'ccusson, qui par cela meme est plus coiirt que dans cette derni^re espece." 1272. Coptotomus difficilis, Lee, Ann. Lye. V, p. 204. North America. " Elongatus, uti-inque attenuatus, rufus, subtilissime aciculatus, tliorace latitudine plus triplo bre^aore, lateribus rectis, apice et basi media uigricaute, elytris pallidis, sutura nigra, maculis latis discoidaliljiis, fuscis, margiue postice. Long. •28." "Specimen unicum ad Colorado." This is considered by Crotch (Rev. N. Am. Dj-tisc, p. 413) to be the same as Dytiscus interrogatus Fab. (No. 911).— D. S 1273. Coptotomus serripalpus, Say, Trans. Ann. Pliil. IV, p. 443. Mexico. " Yellowish ; elytra brownish varied with whitish. Body oblong-oval, honey-yellow ; head black on the posterior margin ; labial palpi with the penultimate joint crenate or bituberculate before ; thorax on the middle of the anterior and posterior margins broadly black ; elytra brownish, with very numerous, minute, honey-yellow points ; two very sUghtly impressed strise, with punctures hardly distinguishable from minute inequalities of the surface, and an indistinct part of a series of hardly impressed punctures each side ; from the base near the scutel proceeds a whitish broad vitta, one-fifth of the length of the elytra, bifid at tip ; from the humeral base to the tip proceeds a broad, interrupted and somewhat irregular vitta also whitish ; venter piceous. Length less than three-tenths of an inch." Found on the estate of the Conde del Regla, about ten leagues N.E. of the city of Mexico. 1274. Cybister a;neus, Orm., Rev. Zool. 1843, p. 332. South America. " Ovalis, convexus, ad apicem rotundatus, supra seueus infra niger, labro fusco, thoracis lateribus viridi- seneis. ElytrLs limbo viridi-asneis, pedibus auticis fusco-nigris, posticis uigiis. Mas. . . . Femina elytris laevibus. L. 30 1., 16 mill." " II difiere du C. prosterno-viridis par sa taille plus petite, sa couleur bronz^e, et le presternum qui est tout noir. II habitc le Bresil." I cannot identify this species, but think it may prove to be a variety of C. glaucus, No. 1104. — D. S. 1275. Cybister auritus, Gerst., Arch. Nat XXXVII, p. 43. Africa. " Parvus, nigro-piceus, nitidus, supra teneo-micans, antennis, labro, clypei fascia anteriore, prothoracis marglne laterali testaceis, vel ferrugineis, pedibus anterioribus elytrorumque macula subapicali (interdum obsoleta) rufis ; elytris perspicue triseriatis punctatis, tibiarum posticarum calcare extemo breviusculo, acute lanceolate. Long. 151 m.m. — 17 m.m. Mas et Fern. Var. Fe^/t.jelytrorum disco obsolete et minus confertim pustuloso." " Zu den klciusten Arten dev gattung gehorend, nicht grosser als die von Perty C. marginithorax On Aquatic Carnivorous Coleopiera or D>/tiscida>. 771 belegten, kleinei- der Cyb. Isevigatus, Fab. welchen die hier in rede steliende ait aiich in der Fiirbimg und Zeiehnung sehr ahnlich ist." Two males from Madagascar, three females from Zanzibar. This is probably near C. filicornis (No. 1129), and may possibly be C. marginicollis, Boh. (No. 1280).— D. S. 1276. Uy bister dejeaiii, ^nbe. Spec. p. Cii. India, (Malabar). " Ovatus, postioe dilatatus, ad apicem paulo oblique rotundatiis, convexiusculus, nitidus, supra et infra nigro-piceus ; labro, e|)istomo, thoracis lateribus vittaque longitudinali, simplici, versus elytrorum marginem luteis ; elytris extrorsuni ooriaceo-rugulosis ; pedibus anticis testaceo-luteis, posticis nigro piceis." " Mas : elyti-is inimpressis. Femirut. : striis minimis irregularibus ; thorace dense reticulato-strigoso Long. 20 m.m., larg. 11 m.m." [A description foUoivs, 1. c] 1277. Cybister goryi, Aube, Spec. p. 81. Australia. " Ovatus, postice late dilatatus, ad apicem oblique rotundatus, convexiusculus, nitidus, supra nigro-piceus, infra ferruginous ; labro, epistomo, thoracis lateribus vittaque longitudinali, simiilici, in elytrorum margine luteis ; pedibus anticis testaceo-luteis, posticis feriiigineis. Mas et femitia : thorace et elytris hwibus. Long. 18| m.m., larg. lOJ-m.m." \A description, 1. c, follows this diagnosis.'] This species I should think is allied to Dytisous atratus (No. 1100), but it appears to be paler be- neath.— D. S. 1278. Cybister insularis, Hope, Proc. Ent. Soc. 1842, pp. 39 and 47. Tasmania. " Niger, capita integi-o convexo, thorace sub lente subtilissime punctate, marginibus exterioribus flaves- • entibus ; elytiis nigris flavo-marginatis, disco binis lineis punctorum hand fortiter impresso ; corpore infra nigro nitido, pedibus quatuor anticis flavo-ornatis, posticis atro-piceis. Long. lin. 8, lat. lin. 4^." This is probably a Homseodytes near Dytiscus atratus (No. 1100). — D. S. 1279. Cybister jordanis, Reiche, Ann. Soc. Ent. Fr. 1855, p. 637. Syria. " Mas etfemina : thorace elytrisque liievibus. Long. 33-35 m.w. (15-1 6 lig.) lat. 1 7-18^ m.m. (8-8-| lig.) " Ovalis, postice dilatatus, ad apicem subrotundatus, minus convexus, nitidus ; supra nigro- viridis infra testaceohiteus ; palpis, antennis, mandibulis, labro, epistomo, thoracis lateribus, vittaque longitudinali apice subhamato-dilatato elytrorum latera versus, testaceis ; pedibus testaceis, tibiis intermediis posticisque f uscescentibus. " [This is followed hy an expatided description.^ " La femelle entierement lisse comme le male, sur le corselet et les elytres, n'en diifere que par une plus grande dilatation du corps, au dela du milieu." " Des eaux de Jourdain." " Cette espece resemble, pour la coloration, au mas du Cyb. roeseUi, mais sa forme est pluu allong^e et moins elliptique." It is doubtful whether this be a distinct species from D. rceselii, (vide Nos. 11 GO and 1170). — D. S. •iBANS. KOY. ni'B. SOC, N.S., VOL. II 5 G 772 On Aquatic Carnivorous Coleoptcra or Dijtiscidce. 1280. Cybister marginicollis, Boh., Ins. Caff. I, p. 235. South Africa. " Ovalis, depressiuscuhis, postice magis dilatatus, ad apicem nonnihil rotnndatus ; nitidu.s, supra atro-cseruleus, subtus nigro-piceus ; antennis, Libro, cpistomate pedibusque luteis ; prothorace angiiste luteo-marginato, dorso siibtilissime, longitudinaliter aciculato, lateribus confertiin jnmctulato ; elytris triseriatim punctatis ; margine inflexo ferrugineo. Long. 17, lat. 10 m.m. Hab., ad poilum natalense." [.I descriptio7i, I.e., /allows this diagnosis']. It is probable that the species is closely allied to Cybister filicornis (No. 1129). — D. S. 1281. Cybister olivieri, Crotch, Tr. Am. Ent. See. IV, p. 399. North America. " Very near C. fimbriolatus but smaller, vnth the thoracic and elytral margin narrower, the elytral vitta leaves the margin gradually, and is attenuated at about three-fourths. L. 1-10 inch." " Mas, stridulating plate with three vug*. Fern., elytra smooth." " Florida." According to a female recently communicated by Dr. Leconte to me, this does not belong to Megadytes, but is a Cybister unknown to me, and of very doubtful position. — D. S. 1282. Cybister prosternovii-idis, Orm. Eev. Zool., 1843, p. 331. South America. " Ovalis, convexus, postice dilatatus, ad apicem rotuudatus et depressiusculus, nitidus, supra olivaceus, infra niger. Labro ferrugineo, thoracis lateribus viridis, in elytrorum margine viridis, prosternum viridis, pedibus anticis nigro-piceis, posticis nigris. Mas, elytris IfeNabus. Femina. L. 36 1 1., 20 mill. " II habite le Bresil 1" No comparison with auy other species is made, and as the locality is doubtful, the species will not easily be identified. I do not think it would be really from Brazil, and should suspect an African species may be intended. — D. S. 1283. Cybister vulneratus, Klug, Symb. phys. IV, \A. 33., f. 1 (the letter-press is not numbered). Arabia. " Cybister niger, thorace lateribus, elytris (in mare lievibus, remote punctato-striatis, in femina dense aciculatis) macula jjostica sanguineis. Long. lin. 12. Habitat in Arabia deserta." " Statura fere D. immarginati. Fab. at angustior ac dimidio fere minor. Obscurus, niger. Caput obsolete rugosnm, subalutaceum, ore antennisque testaceis. Thorax subrugosus, subalutaceus (in femina aciculatus) antice late sinuatus, postice obsolete bisinuatus angulis productis, lateribus obliquis, vix rotundatis, parum reflexis, late obscure sanguineis. Pectus abdomenque hevia. Abdominis segmenta intermedia puncto utrinque sanguineo. Segmentum ultimum apice obscure sangiiincum. Pedes : Trochanteres anteriores toti, postica apice ferruginei. Femora anteriora apice Inete ferruginea postica obscure sanguLnea. Tibia; anteriores (in mare cum tarsis) rufo-testace. 47. Spain. " Oblongo-ovatus, subtus flavus, sterno nigi'o-piceo, abdominis segmentis anticis nigro-fasciatis ; supra nigro-olivaceus, prothoracis elytrorumque margiue latei"ali auguste ilavis ; coxarum posticanam laciniis obtusis. Long. 11^ lin., lat. 6 lin." " Mas et Femina : elytris Isevibus." " Gehort zur z^veiten abtheilung der Aube'schen Dj-tiscus : bei denen das halssehild nur an den seiten gelb geraudet ist, und sieht, da auch das halssehild dicht puuktirt ist, einem weiblicheu D. punctulatiis, bei dem die flUgeldecken ungestreift waren, etwas ahnlich. Dm-ch die gelbe unter — uud schwaiz- olivengriine oberseite ist er mit derjenigem form des D. margiualLs, bei welcher die weibchen glatte flUgeldecken haben, zu vergleichen : von dieser weicht er jedocli sehr auflalleud diu'ch etwas stumpfere spitzen der hinter huften, schwarze zeichnung der unterseite, dicht punktirtes und nur an den seiten gelb eingefasstes halssehild ab. "Vergleichen wir endlich den D. pisanus, so zeigt die neue art etwas weniger stumpfe und sclimalere spitzen der hiuterhuften, glutte flUgeldecken und ein nur an den seiten gelb gev;indetes halssehild. Dieses ist hier ausserdem sehr wenig verflacht und die gelbe einfassung sehr schmal. Der kafer ist langlich-eifdrmig, unten gelb, oben schwarz-olivengi-und, glanzend. Der mund, die taster, die lefze und der vorderrand des kopfs sind gelb, ebenso die fuhler, ein fleck vor den augen und eine winklige zeichiiung zwischen diesen roth. Der kopf selbst ist weuig gewijlbt, sparsam sehr feiu puuktirt glanzend. Das halsschUd ist kurz, quer, 2.^ mal so breit als lang, an den seiten nach vorn verschmalert, zieinlich gerade, zart gerandet, und schmal gelb, vorn breit uud flach ausgerandet, an der basis gerade, die iiinterecken spitzwinklig, die vorderen vorgezogen und spitz, herabgebogen, ziemlich gewolbt, an den On Aqtuitic Carnivorous Coleoptera or D;/tiscidiB. 775 seiten sehr weuig verfl;iclit, dicbt fein piuiktii-t, matt gliinzeucl. Das schildchen ist lioi-zflivmig, schwarz. glatt. Die flugeldecken sind langlicli-eifdrmig, vom so Tn-eit als die basis des halsschildes, an den seiten selir wenig geruiidet, hinter der mitte am breitesten, gegen die spitze allmiihlig veischmalert und tier stnmpf abgerandet, miissig gewOlbt, zerstreut und fein, gegen die spitze dichter nod deutlicber punktirt, uV)er die mitte lanfen die gewohiilicben punktreihen ; sie sind ungefurcbt, gliinzend, an den seiten schma) gelb gerandet. Die untereeite ist gelb, das brustbein ganz, die ersten hinterleibssegmente an ihrer basis schwarz. Die spitzen der hinterliuften sind schmal, am ende stnmpf, nur wenig zugespitzt." " Ein weibliches exemplar dieser ausgezeicbneten art. wurde am 14 miirz bei Algeciras in einem klaren wassertUmpel gefangen, in deni sicb indessen noch einige solche kiifer fiinden, die aber uicbt erbevitet werden konnten." Nothing is at present known of this species, but Kraatz has suggested (Berl. Ent. Zeit. XVIII, p. 296) that perhaps it is only a variety of D. jiisanus, but this appears to me not very probable. — D. S. 1294. Dytiscus octopustulatus. Fab., Ent. Syst. I, p. 197. Sweden. " D. niger fronte thoracis lateribus elytronimque punctis marginalibus ferrugineis." "Habitat in Suecise aquis Dom. Com. de Souza." " Medius, antennne ferrugineae. Caput nigrum, fronte late ferruginea. Thorax miu-ginatus, niger lateribus late ferrugineis margine tamen ipso nigi-o. Elytra lasviii, nigra maculis quatuor parvis ferruite convexiore, colore haud a-neo, unguioilisque anticis maris basi haud sinuatis facile distinguendus. Caput latiusculum, antice distiucte convexum, dense subtilissime reticulato-strigosum, nigrum, maculis frontalibus obsoletis labroque ferrugineis, impressionibus anticis satis distinctis, transversalibus, extus in linea angusta continuatis et supra has foveola parva impressa, palpis ferrugineis articulo ultimo piceo. Antennse prothoracis basin snperantes, ferrugineje, articulis ultiniis apice piceis. Prothorax fortiter transveisus, antice angustatus, lateribus leviter rotundatis, subtiliter marginatis, angulis posticis obtusiusculis, basi utrinque vix sinuato ; supra modice convexus, niger, parum nitidus, subtilissime reticulato-strigosus, serie punctoi-um basali medio late interrupta, apicali punctis intermediis remotis. Elytra basi prothoracis latituduie, oblonga, lateribus vix rotundata, postice rotundato-angustata ; supra modice convexa, fusco-picea, subuitida, lateribus vix dilutiora, dense subtilissime irregulariter reticulato-strigosa et punctulata, seriebus 4 e punctis inordinatis satis fortiter impressis, postice sine ordine dispersis, sutura postice punctis nonnullis impressis (an semper 1 ■. Corpus subtus nigrum, obsolete strigulosum, segmentorum ventralium marginibus anguste piceis, processu postico prosterni convexo, lateribus subtiliter marginato ; lacuiiis latei-alibus metasterni subtriangularibus. Pedes ferruginei, femoribus apice except(j nigro-piceis, anticis in mare subtus setosis, supra ciliis nonnullis longis instructis. " Rare, I found one example in stagnant water at Ponoj in Russian Lapland (67°), 19 Aug., 1870." 1303. Gaurodytes nvalis, Sahl., Not. feun. XIV, p. 178. Gothland. " Ovalis, leviter convexus, niger, nitidus, a^neo-micaus, minus dense reticulato-strigosus ; labro, antennis palpisque, apice piceo excepto, et pedibus ferrugineis, femoribus obscurioribus ; prothorace lateribtis 778 On Aquatic Carnivorous Coleoplera or Dijtiscidce. mcxUce rotundato, minus tenuiter marginato ; elytris guttulLs duabiis pellucidis obsoletis. Fem. TA)ng. •11 lin." " G. affini Pavk. affinis, seJ jtaulln brevior et latior, scnlpcma elj-trorum fere ut in G. tai-sato, Zett. Caput latiusculuin, sulitilissime veticulato-strigosum, nigrum, labro maculisque duabus verticis rufis, irapressionibus anticis parvis, sed satis profiindLs ; palpis ferrugineis, maxillaribus apice angiiste piceis, labialibus articulo secundo snbtiis obsoletissime tuberculato-prominulo. Antennie prothoracis basin attingentes, feiTuginese, articulo ultimo apice piceo. Prothorax fortiter transversus, antice angustatus, latei-ibus modice rotundatLs, minus subtiliter marginatLs, augulis anticis productis, acutiusculis, posticis subrectis, basi utriuque obsoletissime sinuato ; supra modice convexus, niger, nitidus teneo-micans, subtiliter sed minus dense reticulato-strigosus, serie punctorum basali medio late interrupta, apicali Integra, ambabus e punctis minutis valde obsoletis et irregularibus constitutLs. Elytra ovalia, basi pro- thoracis latitudine et lateribus cum illo continue arcuata, postice rotundato-angustata ; supra modice convexa, nigra, nitida, seneo-micantia, subtiliter sed minus dense reticulato-strigosa, cellulis latis, iiTegularibus, versus apicem minoribus, seriebus tribus e punctis inordinatis impressis postice sine online dispereis ; guttulis duabus obsoletissimis pellucidis. Corpus suljtus nigi-um, laciniislateralibus metasterni subtiiaugularibus. Pedes ferruginei, femoribus, praosertim posticis, obscurioribus, f\iscis, tarsis posticis unguiculis insequalibus, apice cm-vatis." Rare ; found at Kuopio (63°), in Gothland. 1304. Gaurodytes suturalis. Crotch, Tr. Am. Ent. See. IV, p. 423. North America. " Regularly ovate, black, above slightly bronzed, subopaque ; thorax with the sides hanUy rounded, posterior angles rectangular ; elytra closely reticulate, the sutural region nearly smooth, dorsal punctures evident irregular, the yellow spot beyond the middle is but little evident ; body beneath strigulose, posterior femora obsoletely punctvdate, tibise with a regular subdorsal row of deep punctures. Mas, anterior claws unarmed Length "35 inch." " Nevada." 1305. Hydaticus apicalis. Boh., Ins. Caflr. I, page 239. Caffraria. " Ovalis, convexiusculus, nitidus, suljtus piceus ; capite llavo-testaceo, postice nigro, flavo-trimaculato ; prothorace subtiliter, crebre puuctulato, flavo-testaceo, pone medium vitta transversa lougioii, utrinque abbreviata, nigra, medio ramulum brevem, apice dilatatum anterius emittente, elytris nigris, ilorso parcius, ad latera crebrius flavo-iiToratis, plaga magna, comnuuii, aj)icali flava, medio confertim nigro- irrorata. Long. 12g, lat. 6j m.m." Caffraria interior. \An exteiuled description J olloius this diagnosis.^ The species is probably allied to Hydaticus sobiinus and galla (Nos. 1041 and 2.) — D. S. 1306. Hydaticus aruspex, Clk., Tr. Ent. Soc, 1864, p. 212. China. " Oblongo-ovalis, parallelus, punctato-striatus, subnitidus, niger : capite fiavo, ad basin late nigra (inter oculos, apud vittie nigrie margin em, flavo-bimaculato) ; thorace lateribus rotundatis, mai-ginem juxta undifjue impresso, et antice transverse (sed obsolete et tenuiter) depresso, et pvinctato ; quoad colorem flavo, ;ul basin late et transverse nigi-o (vitta nigra ad medium lata, latera versus teuuior, hand margines attinet) ; scutello transverso-triangulari, nitido nigi'o ; elytris paralleUs, crebre subtUissime punctatis, etiamque seriebus 3 punctorum (quorum externa penitus obsoleta est) omatis, colore nigi-is, 111 ir'.rinibus undique late et sequaliter a humeris penitus ad apicem fla\'is ; corpore subtus nigro-fusco ; jiediliu-; rufis; antemiis rufo-flavis. Long. corp. lin. 61; lat. lin. 3|." '■ Parallel in form, like ruficollis, Fali . though much narrower than that insect; the species liefore u-i On Aquatic Carnivorous Coleoptcra or Dytiscida'. 779 is remarkable also by its broadly llavous or testaceous thorax combined with the uniform blackness of the elytra, relieved only by the broad and evenly-disposed flavous margiaation, which extends from the humeral angles nearly to the apex." " I obtained a single example some years ago in the Gory collection, from China." 1307. Hydaticus baeri, Regt , Aim. Soc. Fr., 1877, p. Ixxviii. Manilla. " Ovalis, sat latus, parum convexus ; siipra flavo-testaceus, capite in vertice et circum oculos et lineis duabus cu)'vis, iirothorace late antice et postice, elytris vittis duabus transversis latissimis sutui'aque ad apicem flavo-guttata nigro-ornatis ; subtus uigor vix ferrugineus ; pedibus testacois prseter posticis nigro- ferrugineis. Long. 13 m.m." [This diagnosis is supplemented (op. cit., p. 355) b>/ an extended description^] It ajjpears probable that the species belongs to the genus Sandracottus, in the neighbourhood of S. Hunteri (No. 1073).— D. S. 1308. Hydaticus caffer. Boh., Ins. Caffr. I, p. 238. Caffraria. " Ovalis, convexiusculus, nitidus, supra flavo-testaceus, subtus ferrugineus ; capite postice nigi-o, cum maculis duabus flavo-testaceis ; prothorace subtiliter punctulato, medio vitta transversa, brevi, nigra • elytris dorso coufertim, confuse uigro-punctatis, lineis tribus tenuibus, fascia transversa pone medium maculaque obsoleta apicali, flavo-testaceis. Long. 13, hit. 7 m.m." " Cafii'aria orieutalis et interior." \_Thisdiiii/)iosis is followed, I.e., by an extended description.] It would seem that the species is probably closely allied to Hydaticus galla (No. 1042). — D. S. 1309. Hydaticus congestus, Klug, Ins. Mad., p. 13G. Madagascar. " H. testaceus, coleoptrorum disco punctis, fascia dorsali maculaque postica confluentibus uigris. Afas. long. lin. 4J." " Statura fere Dyt. cinerei, F., at multo minor. Caput fulvum, margine postico lineaque frontali angulari nigris. Thorax fulvus, margine antico et postico nigris. Pectus fulvo-testaceum. Abdomen testaceum, segmentis basi utrinque nigris. Scutellum nigrum. Elytra testacea, punctis lineolisque arcuatis ubique confluentibus, fascia obliqua media maculaque submarginali postica nigris, margine exteruo testaceo immaculato. Pedes testacei." The description being confined entirely to colour, I cannot determine whether this is allied to Hydaticus signatipennis (No. 1083) or not. — D. S. 1310. Hydaticus discoidalis, Hope, Ann. Nat. Hist. XI, 1843, i>. 3G4. Africa occ. "Sp. 35, Hydaticus discoidalis, Hoi^e. Long., lin. 5|; lat., lin. 3. AfEnis Hydat. dorsigero, Dupont, at minor. Oblongo-ovalis, thorace obscure testaceo, suturali parte elytrorum nigra, lateribus testaceis, punctis minutisque per discum aspersis, corpore infra ferrugineo, jiecUbus concoloribus." It is possible this may prove to be only small Hydaticus dorsiger (No. 1029). — D. S. 1311. Hydaticus fulvo-notatus, Clk., Tr. Ent. Soc. 18G4, p. 221. Africa occ. "Ovalis, depressus, nitidus, niger, fulvo-notatus; capite rufo, ad basin late et transverse nigro; thorace antice excavato, ad basin sinuato-rotundato, lateribus vix rotuudatis, apicem versus transverse leviter l)unctato, nigro, lateribus late flavo-rufis ; scutello triangulari, Isevi, nigro ; elytris latis, subtilissime punctatis, etiamque puuctoruni seriebus 3 nigris ; basi, fascia post media, et apice rufo-flavis ; basis TRikNS. Boy. DUB. SOC, N.S., VOL. II. 5 H 780 On Aquatic Carnivorouti Colcoptera or Dytiscidce. fascia ornatur nee baseOiS inarguiem nee suturam attingenti, latiori ad latera, attenuation versus scutellum, fascia post-media internijrta est, latior ad margincm, deinde irregularis et angulata macula minori con- tinuitur, macula secunda etiam minori suturam mediam approximat ; apicera juxta sed haud attingens, macula latior ad marginem, attenuatior versus (sed neque pertingens) suturam ; margo quoque i[)se fiavus est: corpore subtusfuseo j pedibus rufo-fuscis, anticis flavis; antennis flavis. Long. corp. lin. 5| ; !iit.,lin. 3i." Cape Coast Castle, during the short rainy season. 1312. Hydaticus histrio, Clark, Tr. Ent. Soc. 1864, p. 221. Northern India. ■' Ovalis, modice attenuatus, modice convexiusculus, niger, flavo-omatus ; capite flavo, ad basin late et transverse nigi-o ; thorace nigro, ad latera late flavo ; scutello triangulari, nigro ; elytris subparallelis, pimctorum seriebus duabus undique (punctis confertis, minutis, et inajqualiter dispositis), quoad colorem nigris, apud basin (sed baseos marginem haud omnino attingens) macula subtriangularis ante medium elytrorum inter strias priniam et secundam sese dirigit, vitta etiam marginalis a humeris propemodum apicem attingit ; coipore subtus nigi-o ; pedibus flavis, posticis fuscis ; antennis flavis. Long. 6 lin., lat., lin. 3." " A distinct species from Northern India, an example of which I received some years ago in the Gory collection. It is allied to ■I'ittatus, Fab., but besides being of a pattern which it seems almost impossible to i^lace as an extreme variety of that variable sjiecies, it is manifestly narrower and more constricted in form." 1313. Hydaticus lateralis, Cast., Et. Ent. p. 97. South America. " Noir ; bord anterieur de la tete et cotes du corselet d'uu jaune ferrugineux ; elytres avec un trait de meme couleur, allonge et place deniere Tangle hiimeral, pres du bord lateral, et s'eteiidaut jusque vers le tiers de I'elytre ; un autre place sur le bord et qui, naissant vers le milieu, va jusqu' a I'exti'emite ; et enfin une tache triangulaire situee pres du bord lateral, un peu en arriere du milieu ; dessous du coi^ps d'uu noir briinatre ; autenues et deux premieres paires de pattes d'uu brun jaune. Long. 6 lignes, larg> 3J lignes." Cayenne. This insect is also described by Aube (Spec. p. 189). — D. S. 1314. Hydaticus madagascariensis, Aube, Spec. p. 210. Madagascar. " Ovalis, convexus, postice depressiusculus ; thorace nigro, ad latera luteo ; elytris nigris, cum vitta versus latera longitudinali, paulo obliqua, punctis duobus ad basin transversim dispositis, alteroque ad apicem, luteo-testaceis ; corpore subtus nigro-piceo. Long. 14^ m.m., larg. 8i m.m." \A description follows, 1. c, this diagnosis.] 1315. Hydaticus nauzieli, Fairm., Ann. Soc. Fr. 1859, BiiU., p. 52. France. "Long, 12 m.m. Ovalis, parum convexus, rufescens ; capite prothoraceque dilutis, cajiite basi ; prothorace vix iufuseati, hoc basi angustissime nigi-o-marginato ; elytris brunneis, rufo-vermiculatis, margine externo rufescente ; subtus cum pedibus, i-ufo-testaceus. Trouve a Sorreze par M. le professeur Nauziel ; distinct par sa coloration de toutes les espcces du meme genre." I supjose this to be Dytiscus leander (Xo 1032). — D. S. 131G. Hydaticus nigrc-marmoratus, Clk., Tr. Ent. Soc, 1864, p. 220. Angola. " Oblongo-ovalis, depressiusculus, Isevis, rufo-testaceus, nigro-maculatus : caj)ite rufo, ad basin trans- verse et ad interiorem oculoram marginem nigro ; thoi-ace lato, subtilissime punctulato, antice excavato On Aquatic Carnivorous Coleoptera or Dytiscidce. 781 (angulis anticis prominulis et acutis) ad basin subsinuato ; quoad colorem rufo-testaceo, ad basiu temiiter nigro ; scutello triangulari, huvi, uigro ; elytris sat latis et ad apiceui sat acuminatis, iiuditiue seriebus punctorum rarorum tiibus distinctis ornatis, rufo-testaceis, sutura jequaliter et seriebus macularuin 3 insequalibus nigris ; Use macula; siuuataj, longitudinalitev productue, iuterruptre, in vittis apud punctorum aeries elytra ornant, et puucta ipsa plerumque maculis minoribus circularibus cinguntur : corpora subtus fusco ; pedibus flavis, tibiis posticis fuscis ; antennis flavis. Long. corp. lin. 6 ; lat. lin. 3|." " H. nigro-marmoratus will take its place near H. dregii, which it generally resembles in pattern : it is, however, abundantly distinct : the sutural line is very evenly black : along the first row of punctures (which are distinct but widely separated) runs an uneven, irregular, longitudinal marking from the base to the apex (in some places broader than but for the most part about equal in breadth to the sutmul marking) ; this is interrupted in front of the middle ; the second longitudinal marking is more irregular still, it is placed rather within the second line of punctures, is narrower than the first, and con- fluent with it near the base and apex ; the punctures themselves (bemg on the outer side of this marking), and also the punctures of the third row, are each surrounded by a regular and circular mark- ing ; the tliird line of black coloration is between the second and third rows of punctures, and consists of three markings — one near the shoulder, which is coufiuent with the first at the base, one medial, wliich is shorter and more minute, and a third post-medial, which is much broader, extending from the second row of punctures to the margination ; a"; the medial margination there is also another fuscous marking." "There is no other species known to me with which H. nigro-marmoratus can be confounded." 1317. Hydaticus nigro-vittatus, Clk., Tr. Ent. Soc, 1864, p. 222. Japan. " Ovalis, convexiusculus, sat latus, et ad latera nonnihil rotundatus : thorace leviter puuctaio et ad latera apud basin reticulato, vel quasi irregulariter acuducto, quoad colorem testaceo-rufo, marginibus ad apicem et basin tenuiter nigris; scutello triangular!, Isevi, nigro; elytris undique punctorum seriebus duabus (punctis raris et aliquando obsoletis), omnino subtilissime et crebre punctatis, testaceis vel rufo- testaceis ; vitta suturali alteraque (vel duabus approximatis) undique nigris ; inter vittas et margines elytra quasi nigro-irrorata maculis subtilissimis sparguntur ; hse maculae autem non confuse aggregate, sad plus minus ordinibus dispositse sunt : corpore subtus, pedibusque rufo-fuscis. Long. corp. lin. h • lat. lin. 2i." " Allied to H. leander of South Europe, and, at first sight, only a variety of that species." This is, I should think, pretty certain to prove a synonym of Dytiscus grammicus (No. lU28). — D. S. 1318. Hydaticus paganus, Clk., Tr. Ent. Soc, 1864, p. 215. Congo. " Oblonco-ovalis, parallelus, punctorum tri-serie ornatus, niger, nitidus : capita Isevi, rufo, ad basin transverse nigro ; thorace haud ad basin smuato, antice excavato, rufo-flavo, ad medium subtilii-er fuseo- adumbrato, margmibusque antico et postico nigiis (hoc ad medium latiori, illo trausverso ajquali attenuato) ; elytris parallelis, sat productis, punctorum seriebus 3 (puncta iutervallo distantia, haud pro- funda, et aliquando obsoleta simt), quoad colorem nigris, humeris (macula parva angulata) marginibusque irra'mlariter testaceis vel rufo-flavis ; corpore subtus fusco-nigro ; pedibus antennisque tlavis, illorum femoribus tibiisque posticis fuscis. Long. corp. lin. 6| ; lat. lin. 3|." " Nearly allied to H. capicola, Aube ; but differing from it by its more pai-allel form and entirely rufo- flavous head and thorax ; the elytra also, Instead of being more or less flavous irrorated with black, are entii-ely black, the humeral angle being flavous, and also the line of margination, obscurely and inter- ruptedly, but more distinctly flavous near the apex." Gold Coast, a single specimen. 5 H 2 782 On Aquatic Carnivorous Coleoptera or Lyiiscida'. 1319. Hydaticiis philippensis, Wehncke, Stet. Eiit. Zeit. XXXVII, p. 197. Philippines. " Ovalis, convexus, thorace nigro, lateribus late luteo, elytris nigris, vittis duabus fasciaqiie pone basin testaceis subtus nigro-feiTugineiis, pcdibus anticis flavis. Long. 14 — 15 ni.m. " Dieso art stelit dem II. bowringi, Oik. aus Japan am niicbsten, durch das dunklere halsschild und die gelbe querbinde an der basis der fliigeldecken imterschieden. Der Kopf ist schwarz, der vorder tlieil gelb, halsschild schwarz mit breitem gelbeu seitenrande. Fliigeldecken schwarz, ein quei-streifen an der basis, und zwei liingsstreifen auf jeder seite gelb. Der querstreifen hiingt mit dem innern lilngsstreifen zusammen und ist an der nath unterbrochen, die langsstreifen vereinigen sich hinten an der spitze. Die unterseite mit den liinterbeinen pechschwai'z, die vorderbeine ganz gelb, die scMenen der mittelbeine briiunlich." 1320. Hydaticus riehli, Wehncke, Stet. Ent. Zeit, XXXVII, p. 195. Cuba. " Elongato ovalis, thorace rufo-luteo, in medio nigi'o-maculato ; elytris rufo-testaceis crebre nigi-o- irroratis. Long. 15 J m.m." " Dem H. capicola, Aube, sehr iihnlich, jedoch betriichtlich grosser, durch das ktvrze halsschild imter- schieden, auch sind die schwarzen sprenkelnauf den fliigeldecken feiner und stehen weitlaufiger, wodurch das Thier eine hellere farbe bekommt. Kopf ausserst fein punktii't, schwarz, der mund und drei in dreieck stehenden flecke auf der stLrn rothgelb. Hallschild sehr kurz, kaum ein fiinftel so lang als die fliigeldecken, auch etwas schmiiler als diese, glatt, mit einer reihe grosserer punkte am vorderrande, rothgelb, ein schmaler streifen am hinterrande und ein langUcber querfleck auf der mitte schwarz. Sihildchen ganz schwarz. Fliigeldecken rothgelb mit feinen schwarzen sprenkeln, die den aussenraiid frei lassen, ziemlioh dicht besetzt. Die unterseite mit den liinterbeinen schwarz, die vorderbeine gelb, die schenkel der mittelbeine in der mitte und die schienen dvmkel." This I believe is a species of Khantus. — D. S. 1321. Hydaticus ussheri, Clk., Tr. Ent. Soc. 1864, p. 214, pi. 14, f. 2. Cape Coast Castle. " Ovalis, posiice depressus, obscure undique bi-punctato-striatus, niger vel rufo-niger, maculis qnibusdam flavis : capite flavo, ad basin late et transverse fusco ; thorace flavo, ad medium (et prsesertim apud basin) fusco-adumbrato, basi ipsa usque ad margines tenuiter fusco-nigra; elytris subparallelis, subtiliter, undique puncta in striis duabus ordinata disponuntur ; hfe striae interdum penitus obsolete sunt ; ad sutui-am etiam rare puncta minuta serie ordinata apparent ; elytra nigra, vel fusco-nigra, margo autem usque ad apicem ipsum rufo-flavus, vitta etiam transversa flava ad basin (haec, forma seqiiaU, tenuis nee suturam nee marginem attinet) ; tres alise macula; undique apparent (nee forma distinctaj nee omnino flavae sed nigro-maculata aut iiroratae), prima apud marginem ante mediimi, baud ^-ittam mediam attinet, nigro-niixta, sed ad marginem omnino flava, secunda pone medium vitta arena ta baud suturam attLngit, figura ina>qualis, nigro-macnkita, tertia ad apicem plaga etiam flava baud suturam attinet ; antennis flavis, corpore subtus rufo-fusco ; pedibus rufo-flavis, femoribus posticis fuscis. Long. corp. 7 lin. ; lat. lin. 4|." 1322. Hj-daticus verecundus, Clk., Tr. Ent. Soc. 1864, p. 213. ? Java or South America. " Ovalis, parallelus, punctato-striatiis, nitidus, niger flavo-notatus : capite flavo, ad basin transverse nigro, inter oculos maculaj Hwx flavse triangulares, sese attingentes, apparent : thorace brevi, lateribus rotuudatis, antice transverse tenuiter depresso, flavo, marginibus antico posticoque late nigris (margo anterior, latitudine Kqualis, baud latera attinet ; margo basalis, ad medium anteriore latior, sensim angustior fit, et tenuis latera pertingit) ; scutello triangulari, nigro ; elytris sat parallelis (pone medium sublatioribus), apice rotundato, baud attenuate ; punctorum tres series undique apparent, puncta dLstantia, On Aquatic Carnivorous Coleoptera or Dytiscidce. 783 minime profunda, attainea perspicuii et in seriebus secunda et tertia minus obsoleta ; quoad colorem elytra nigra apparent ; vitta basalis a scutello ad liumeros extendit, haud basin attingens, tenuis jequalis, recta (aut sub-circularis et ad marginem medium leviter sese flectens), ad vittse terminum margo usque ad humerum late flavescit ; pone medium inter seriem punctorum tertiam et marginem macula flava apparet, subquadrata aut aliquando in duas divisa ; ad apicem quoque altera, major, figura et statura incerta (nunc macula iasularis, ad ipsum marginem, nunc vitta transversalis, insequalis, communis, lata, et ad apicem ipsum pertingeus) ; corpore subtus nigi'O-fusco ; antennis flavis ; pedibus flavis, posticis fuscis et flavo-annulatis. Long. corp. lin. 4 ; lat. lin. '2^." " One of the smallest species of the genus ; and to be also recognized by its more than usually distinct punctuation, as well as by the pale regular transverse band on its black elytra." The species is probably South American, and allied to H. rectus (No. 1017). — D. S. 1323. Hydaticus xanthomelas, Brulle, Aube, Spec, p. 181. Corrientes. South America. " Oblongo-ovalis, convexiusculus ; thorace rufo-testaceo, antice et postice nigro ; elytris nigris, cum margine lato, in medio longitudinaliter di\dsa vitta(pie ad basin bi-interrupta luteis ; corpore subtus nigro-piceo. Long. 10 m.m. larg. 5^- m.m. [^Aube, 1. c, r/ives a description in addition to the above dia(/no&-is.l 132Jr. Hvdiocanthus auritus, Regt., Ann. Soc. Fr. 1877, p. Ixxix. Manilla. " Ovalis, sat elongatus, po.stiee attenuato-acuminatus ; omnino niger, prseter macula testacea ad angulum anticum prothoracis, antennse pedesque antici et intermedii testacei, postici nigro-ferrugiaei. Long. 2J a 3 m.m." At p. 359, op. cif., an additional description is given of this species : it should no doubt be assigned to the gentis Canthydrus. — D. S. 1325. Hydrocanthus fasciatus, Steinl., Atti. Soc. Ital. Sci. Nat., XII, p. 250. South America. " Oblongo-ovalis, obconicus, antice ampliatus, nitidus ; capite thoraceque ferrugineis, indistincte punctulatis ; elytris ad basin thoracis latitudine, nigro-piceis, fascia media margiueqne laterali ferrugineis ; corpore subtus, ore antennis pedibusque rufo-testaceis. Long. lin. I'l, lat. lin. 0'65." Buenos Ayres. I cannot fonn a valid opinion as to what genus this should be referred to ; but it clearly does not belong to Hydrocanthus, huj., op. — D. S. 1326. Hydrocanthus Hneatus, Wehncke, Berl. Zeit. XX, p. 221. Mexico. " Ovatus, postice attenuatus, convexus, nitidus, capite thoraceque ferrugineis, hoc postice fusco, elytris nigris, testaceo-lineatis, pedibus luteis. Long. 3 m.m. " Durch die gelbgestreiften flligeldecken leicht kenntlich, eiformig, nach hinten verengt, gewolbt und glanzend. Kopf und halsschUd rothbraun, glatt, letzteres am hinterrande etwas dunkler und mit einzelnen feinen Punkten besetzt. Flligeldecken schwarz, der seitenrand imd drei langsstreifen gelb. Die streifeu beginnen an der basis und erreichen, der erste und dritte fiist die s])itze, wahrend der mittlere hinter der mitte verschwindet. Der iiusserestreifen theilt sich vorn gabelfonnig und vereinigt sich an der schulter mit dem seitenrande. TJnterseite ist rothbraun, die beine gelb." The description agrees with Canthydrus "centralis, (No. 49), except that the thorax is described as being only dark behind : the name cannot be used on account of the Suphis lineatus, Horn, which belongs to the same genus. — D. S 784 On Aquatic Carnivorous Coleoptera or Dytiscidw. 1327. HydrocanthuH nanulus, Lee, New. spec. Col. I, 1863, p. 22. North America. " Elongato-ovalis, postice paulo magis attenuatus, rufo-testaceus, nitidiis, impunctatiis, elytris panic saturatioribus, antennis petlibusque palUdioribus. Long. -05." "Louisiana ; Dr. ScLaiim. The very small size at once distinguishes this from all other species of the genus; it is more regularly oval, and less convex than the others." 1328. Hydrocanthus rubripes, Boh,, Eugen. Res., p. 19. Monte Video. " Oblongo-ovalis, convexus, niger, nitidus, postice modice attenuatus ; capite, anteunis, prothorace ad latera confuse pedibusque rubris ; elytris tiibus minonim punctorum seriebus leviter impressLs. Long. 2i, lat. 1| m.m." " Summa similitudo H. nigi-iui, semper dimidio fere minor, prtesertim brevier, posterius minus attenuatus. Caput feri-ugineum, nitidum Iseve, postice parum infuscatum, apice utrinque puncto profundo impressum. Palpi ferruginei. Oculi rotnndati, modice convexi, glauci. Antennse ferrugineae. Prothorax longitudine duple latior, apice late, leviter rotundato-emarginatus, basi utrinque subsinuatus, medio breviter Bub-triangulariter productus, lateribus tenuiter reflexo-marginatis, pone apicem leviter rotundato-ampliatis, angulis anticis antrosum prominulis, acutis, posticis fere rectis ; superne convexus, niger nitidus, extrorsum plus minusve late, confuse ferrugineus, Ijevis, antice postice et ad latera subtiliter punctulatus. Scutellum nullum. Elytra antice subtruncata, prothorace non latiora at illo fere duplo et dimidio longiora, pone basin apicem versus sensim angiistata, apice conjunctim subacuminata ; nigra, nitida, extrorsum interdum confuse ferruginea, singulo .seriebus tribus e punctis parris, sat crebris notato ; margine inflexo, fen'ugineo. Corpus subtus nigro-piceum, nitidum, subtiliter, crebre pimctulatum. Pedes rufo- ferruginei." This is no doubt a Canthydrus, and is perhaps allied to C. brevicornis (No. 45). — D. S. 1329. Hydrocanthus socius, Sahl., Act. Soc. Fenn. II, 2, 1844, p. 516. Rio Janeiro. " Oblongo-ovatus, postice angustato-acuminatus, ferrugineo-testaceus ; elytris ad basin thoracis latitudine, brunneis, testaceo-irroratis, sutura apiceque obscurioribus, capite et thoraee fulvescenti testaceis. Long. If lin., lat. H lin." " Statura et magaitudo H. laevigatL Caput convexum, fulvo-testaceum, subnitidum, Iseviusculimi. Oculi magni, grisei, medio nigri. Palpi et antennae testacea. Thorax fulvo-testaceus, nitidus, glaber, antice parum infuscatus, longitudine sua plus duplo latior, antice late emarginatus, angustior, angulis subacutis, lateribus parum rotuudatis, postice latior, angulis subrectis, basi sinuatis. in medio breviter sed acute productus, supra laevis, punctis paucis ad marginem anteriorem subtUissimis. Scutellum non conspicuum. Elytra elongata, antice thoracis latitudine, usque ad medium sensim rotiuidato-dilatata versus apicem angustato-acuminata, brunnea, testaceo-irrorata, sutura apiceque obscurioribus, margine inflexo testaceo, pilis raris versus apicem albescentibus sparsis. Corpus subtus testaceo-ferrugineum abdomine infuscato. Pedes testacei." This may possibly be a sm.all species of Hydrocanthus near H, debilis (No. 78), or a Canthy dms.— D. S. 1330. Hydrocanthus testaceus, Boh., Res. Eugen., p. 19. China. " Oblongo-ovalis, postice attenuatus, convexus nitidus, rufo-testaceus ; prothorace Isevi, antice postice- que tenuiter infuscato ; elytris impunctatis. Long. 2, lat. 1^ m.m." " Statura H. nigrini, multo minor, aliter coloratus. Caput modice convexum, rufo-testaceum, nitidum Iffive. Palpi rufo-testacei. Oculi rotundati, parum convexi nigri. Antennae rufo-testaceae. Prothorace longitudine duplo latior, apice late, leviter rotundato-emarginatus, basi utrinque sub-sinuatus, medio On Aquatic Carnivorous Coleoptera or Dytiscidoi. 785 parum productus, lateribus pone apicem magis, deiii basin versus sensim ampliatiis, angulis auticis antrorsum prominulis, acuminatis, posticis rectis ; superne convexus, rufo-testaceus, nitidus, margins apicali et basali tenuiter infuscatiis. Scutellum nullum. Elytra obconica, antice subtruncata, prothorace non latiora at illo fere duplo et dimidio longiora, pone basin apicem versus sensim angustata, apice con- junctim sub-acuminato, rufo-testacea, nitida, non pimctata. Corpus subtus rufo-testaceum, nitidum, obsolete punctulatum. Pedes nrfo-testacei, nitidi." This is no doubt a Canthydrus very similar to Hydrocanthus flavus, (No. 70). — D. S. 1331. Hydrocoptus dauricus, Motsch., Scbrenck Eeise, p. 100, pi. VII, f. 3. Amurland. " Elongato-ovatus, postice attenuatus, subdepressus, subsericeo-nitidus, testaceus ; capite antice, thoracis maculis, elytris lineis utrinque septem plus minusve confluentibus, antennarum annulis corporeque subtas nigro-f uscis, elytris striis jiunctorum distinctis tribus, alternis solum longitudinaliter undulatis, interstitiis subtilissime punctulatis fere glabris ; thorace trausverso, rectangulo. Long. 2 1., lat. 1 1." " Un peu plus grand que les Hydr. griseostriatus, Dej., et Hydr. borealis, GylL, plus acumine posterieure- ment, et facile a reconnaitre par les trois lignes de points, forteuient impx-imes qu'on voit sur chaque 61ytre." Northern Amurland and the Alps of Dauria. This is I should think, Dytiscus alpinus (No. 529) or a very closely allied species. — D. S. 1332. Hydrocoptus mixtus, Motsch., Bull. Ac. Pet., 1860, II, p. 515. Kii-ghiz steppes. "Elongato-ovatus, depvessus, nitidus, punctatus, supra fusco-testaceus, subtus niger, fronte, thorace antice, elytrorum Ijasi pedibusque plus minusve testaceis ; thorace valde ti-ansverso, postice clilatato ; elytris ovatis, utrinque punctato-bistriatis, interstitiis fortiter pimctatis, corpore subtus fere glabro. Long. \\ lin., lat. f lin." " Plus large que notre Hydroc, 6-pustulatus et avec les couleurs du dessus plus confondues entre elles, de sorte que souvent toute la surface des ilytres devient claii-e. Cette espece est tres commune dans toutes les eaux douces des steppes des Kirghises." I cannot indentify this species, said to be near Dytiscus palustris. — D. S. 1333. Hydrocoptus obscuripes, Motsch., Schrenck Eeise, p. 100, pi. VII, f 2. Amurland. " Oblongo-ovalis, depressiusculus, punctatus, subnitidus, sparsim pilosus, niger, vel nigro-piceus, elytrorum lateribus subinfuscatis, antennarum basi, capitis margins postice pedibusque piceis; elytris sutura subelevata, utrinque linea punctorum vix distincta impressa. Long. 1\ 1., lat. 4 1." "II ressemble beaucoup a nos H. nigrita, piceus, nivalis et pareils, mais il est plus allonge, plus parallele et un peu plus grand. Trouv6 par M. Schrenck dans les eaiix du fl. Amour, et par moi en Mongolie pres de Kiachta." This is probably a species of Hydroporus ; the figure, I. c, gives no assistance to its recognition. — D. S. 1334. Hydrocoptus rufulus, Motsch., Et. Ent. 1859, p. 44. Burmah. " Une seconde espece, tr6s voisine par sa taille, sa forme et ses couleurs (to Hydrocoptus subvittulus) se trouve au Birma. Elle est proportionellement un peu plus large et plus ovalaire que le Hydrocoptus subvittulus, la strie testacce sur les elytres est comme eftac6e par le fond brun-roussatre des dernieres ; le corselet parait plus fortement attenue vers la tote qui de son c6t6 est un peu plus arroudi au chaperon." This is possibly the same as Hydroporus rubescens, (No. 9). — D. S. '786 On Aquatic Carnivorous Coleoptera or Di/tiscidce. 1335. Hydroglyp)ms flaviculus, Motsch., Bull. IMosc. 1861, J, p. 108. Ceylon. " Elongato-ellipticus, subdepressus, subnitidus, densissLme subtiliter pimctulatus, nifo-testaceus, elytris pallidis, liis basi, sutura, iitrinque macula postica bifurcata abdomineque nigro-piceis, oculis nigi-is j thorace valde transverse, utrinque ad basin obliqtie impresso, lateribus angulisque posticis rectis ; elytris tlioracis latitudine, antice parallelis, ad suturam utrinque profundo iinistriatis, stria Integra. Long ^ 1., lat. f I." Colombo. I cannot form any decided opinion as to the place of tliis name ; it may possibly prove a species of Bidessus. — D. S. 1336. Hydroporomorpha parallela, Bab., Tr. Eut. Soc. Til, 1841, p. 15. pi. 1, f. 3. Brazil. " Oblonga, antice obtusa, postice acuminata, lateribus parallelis, supra rufa, thorace antice et postice elytrisque (apice marginibusque exceptis) fuscis ; corpora subtus, antennis pedibusque fusco-i-ufis. Long. 2, lat. | liu." " Head short, transverse, rounded in front, with two longitudinal slightly impressed fovese between the eyes. Thorax transverse, short, broadly emarginate in front ; the angles acute ; lateral margins rounded ; posterior margin straight, very slightly produced in the middle over the scutellum ; disc smooth, ^\^th a transverse row of punctures in front, and a similar one behind, the latter broadly interrupted in the middle ; rufous, with the anterior and posterior margins fuscous, Scutellum small, triangular, transverse, fuscous. Elytra of the same width as the thorax, oblong, the sides parallel for three-foiu-ths of their length, then strongly rounded to the apex, which is acute and prominent ; disc coarsely punctured, with one central row of more regular punctures upon each ; fuscous, with the exception of the apex and external margins, which ai'e rufous. Body beneath, legs and antennse, diill rufous. Hab., Rio de Janeiro." This is a species of Celina allied closely to C. lougicornLs, No. G.52.— D. S. 1337. Hydroporus aberrans, Clk., Tr. Ent. Soc. Lond. third ser. I, p. 426. Java. " Breviter ovatus, latus, parallelus, fortiter punctato-striatus, punctatus, testaceus, rufofusco notatus ; capite le%'iter punctato, rufo-fusco ; thorace antice vix emarginato, lateribus rotundatis, basi pene transverso, crebi'e punctate, testaceo, ad meilium fusco-adumbrato ; elytris sat latis, fortiter undique striis punctatis octo latis omatis, punctatis, testaceis, lineis tribus rufo-fuscis a basi ad apicem subparallelis ; coi-pore subtus fusco, antennis pedibusque rufo-flavis. Long. corj). liu. -t ; lat. lin. ^." " The only example that I have been able to examine of this species is an imperfect one received by Mr. Bowling from Java : it presents very sufficient and strikiug characters ; tlie form of the insect is short and parallel ; the sides of the thorax are much roimded, compi'essed at the anterior and posterior angles ; the elytra are marked by eight deep strise, formed by closely an-anged broad punctures ; in colour the surface is testaceous, the interstices between the first and second, the thii-d and fourth, the fifth and sixth strise being irregularly rufo-testaceous." The type of this species has been destroyed, I am doubtful to what genus the insect should be referred. — D. S. 1338. Hydroporus adumbratus, Clk,, Ann. Nat. Hist., 1862, p. 183. Mexico. " Oblongo-ovalis, punctatus, pubescens ; capite fusco, interdum antice rufo-fusco ; thorace flavo, ad basin plus minus fusco ; elytris subtiliter punctatis subpubescentibus, fuscis ; antennis jiedibusque rufo- flavis. T;ong. corp. ^ lin., lat. f lin." "This minute species varies somewhat in size and also in colour; one example before me is of a deep On Aquatic Carnivorous Coleoptera or DytiscidiB. 787 black colour, the thorax being somewhat fuscous ; this same example is preceptibly smaller in size. In the absence of any series of specimens, I can detect no necessarily permanent difference which would constitute it a distinct species. H. adumbratus is less distinctly punctured than H. emilianus ; it is moreover easily recognized by its manifest pubescence." This is a species of Bidessus closely allied to llydroporus pulicarius (No. 308). — D. S. 1339. Hydroponis amandus, Lee, Ann. Lye. V, p. 207. North America. " Oblongus, magis parallelus, piceus, subtiliter punctatus, nitidus, capite parce punctulato, thorace testaceo medio infuscato, antrorsum vLx angustato, lateribus paulo rotundatis, tenuissime marginatis, angulum cum elytris formantibus, striola basali profunda ; elytris fascia pone basin integra, striga subapicali hamata, striolLs brevibus duabus pone medium, margineque tenui pallidis. Long. -06." " Specimen unicum in flumine Gila. Prsecedenti similis, at minor, punctura subtiliore, thorace magis parallelo, angulum cum elytris magis distinctum formante, his stria suturali nulla diversus." A specimen of this species recently communicated to me by its desci-iber shows it to be a Bidessus of small size, belonging to group 5, B. ; the upper surface is finely punctured, and the pale transverse markings on the wing-cases are large and conspicuou.s. — D. S. 1340. Hydroporus angularis, Klug, Symb. Phys. IV, t. 3i, f 1, 2. Nubia. "Thorace postice utrinque impresso, punctatus, testaceus, elytris pallidis, sutura lituraque fuscis. Long. lin. H." " Lectus ad Ambukohl." " Corpus oblongo-ovatum, pallide testaceum, subtus obscurius, inimaoulatum. Caput vix punctatum, cum antennis testaceum, immaculatum. Thorax distincte et confertim punctatus, testaceus, postice longitudinaliter biimpressus, macula marginal! media emarginata fusca. Pedes testacei. Elytra con- fertim punctata, ad basin medio tenuissime longitudinaliter impressa, pallide testacea, sutura lineolisque dorsalibus duabus, interior! longior! et subhamata, exterior! brevissima, fuscis." " Variat lineolis coleopterorum externis obsoletis, internis linea transversa brevi ad suturam oblique descendente basi conjunctis." To be placed in Bidessus ; it is a large species apparently unknown to me. — D. S. 1341. Hydroporus angulipennis, Peyron, Ann. Soc. Fr., 1858, p. 398. Syria. " Oblongo-ovatus, depressus, punctulatus, parce pubescens ; inas niger ; /em. supra pallide ferruginea ; capite antice, palpis, antennis, pedibusque ferrugineis; thorace lateribus valde rotundatis, angulis posticis obtusis ; elytris subparallelis, apice siniiatis, rotundatim attenuatis, subcostatis (Div. Hydr. opatrini, Germ.) Mas, long. 4f, lat. 2^ mm. Fern., long. 3|, lat. 1| m.m." " Ovale allong^, assez deprime, legerement pubescent et finement pointille ; mas, noir obscur,/eTO, d'un ferrugineux pale en dessus, noir obscur en dessous; tous deux ayant le devant de la tete, les antennes a part les derniers articles qui sont assombris, les palpes et les pattes ferrugineux. Yeux saillants, ayant entre eiix deux impressions obliques coudees en dehors anterieurement. Prothorax tr6s court, trfes echancrd en avant avcc les angles anterieurs trSs saillants, deprimes, arrondis, les cotes arrondis en demi-cercle, un peu retrecis en arriere, a peine releves vers les angles, ne formant pas de bourrelet, avec les angles posterieurs tres obtus, cmousses, la base trfes peu et largement prolougee en arriere dans son milieu en pointe tr6s mousse, entierement traversee horizontalement par une impression bien marquee. Elytres presque paraUeles, un peu elargies vers les trois quai-ts poste'rieurs, assez brusquement arrondies, acumine'es en arriere ou elles sont couples subsinueiisement ; elles sont plus larges a la base que le prothorax dans sa plus grande largeur, et forment avec lui un angle rentrant aigu ; les epaules sont saillantes, angulaires TBAKS. BOT. DDB. SOC, U.S., TOI.. U. 5 I 788 071 Aquatic Carnivoroxis Coleoptera or Dytiscidce. et munies d'une tres petite dent, elles sont trts deprimees vei's la suture, la depression bornee sur chaque elytre par une cote elevee placee vers le tiers da la largeur i partir de la suture ; un autre vestige de cote se voit encore vers Ics deux tiers de la largeur, toutes deux sont accompagnees d'line ligne longitudinale de petits points placee centre chaque cote et en dedans de cLacune ; ces cotes sont moins marquees chea \&/em. II doit 6tre plac6 aupres de I'H. ovatus, Sturm." "Taurus, pi-es du Kuleg-Boghaz, dans les Fontaines d'eau vive." This should probably be placed in the genus Deronectes, as it is stated to belong to the " opatrinus group."— D. S. 13-t2. Hydroponis, atomus, Regt., Ann. Soc. Fr. 1877, p. Ixxx. Manilla. " OvaHs, ^ix elongatus, depressus ; capite testaceo ; prothorace testaceo, antice angustissime infuscato, postice maculis duabus griseis \lx coiispicuis notato, subtiliter jiunctato, in disco fere Isevi ; elyti-is sat fortiter punctatis, griseo-testaceis, ad scutellum et suturam obscurioribus, maculis duabus in sutura latis confusisque vix iiotatis, striga suturali nuUa ; prothoracis elytrisque strigis curtis, ad basLa fere contiguis ; subtus i-ufo-testaceus, pedibus concoloribus. Long. 1^ m.m." [This diagnosis is sujipleinented, ji. 361, op. cit., hy a description.'] To be placed in Bidessus, probably near B. dilutus (No. 307). — D. S. 1343. Hydroporus bakewelli, Clk., Joum. Ent. I, p. 413. Australia. " Ovatus, latus, depressus, crebre punctatus, flavus ; elytris flavis, nigro-notatis. Long. corp. If lin., lat. 4-1 lin." " Ovate, broad, somewhat depressed, attenuated towards the apex, flavous : head short, broad ; on either side within the margins of the eyes is a narrow depression ; the surface is finely punctate : thoi-ax broad, rounded in front, the sides marginate, in front and near the base transversely subdepressed ; the surface is finely punctate, flavous, the anteiior and posterior margins being narrowly and evenly fuscous black : elytra thickly and finely punctate, flavous, with two, three or four longitudinal markings of fuscous black : in one of the two examples before me the colour is rather fuscous black, with two intennipted and irregular medial bauds of flavous. The great dissimilarity of pattern between these two examples plainly shows that the sjjecies is subject to much variety ; it may readily be lUstinguished from all others by its sectional characters, the absence of any thoracic fovea, the angle formed by the sides of the elytra and the thorax, and by its smaller size." Moreton Bay. This may perhaps be a species of Chostonectes. — D. S. 1344. Hydroporus basinotatus, Keiche, Ami. Fr. 1SG4, p. 234. Tangiers. "Long. Si m.m., lat. 2 m.m. Breviter ovalis, leviter convexus, parce pubescens, subnitidulus, nigro- piceus ; ore antennarum basi, maculis elytrorum pedibusque testaceo-rufis. Caput minutissime punctatum. Thorax capite vix duplo latior, latitudine tertia parte paulo longior, antice valde angustatus, a latere rotundatus, supra scutellum triangulariter lobatus, crebre minutissime punctatus, sulco transverso, grosse punctato antice instiiictus. Elytra basi thoracis basi latitudine ac jiroxime ampliora, medio parum latiora, apice conjunctim rotuudata, densissime minutissime punctulata, basi utrinque testaceo-maculata ; scilicet litura loiigitudinali ad scutellum, macula oblonga in medio, altera arcuata ad humerum interdum secundum marginem descendente : his maculis ad basin interdum confluentibus ; elytrorum epipleuris basi testaceis. Subtus metathorace fortiter, mesothoraceque le\'iter punctatis ; abdomine minutissime punctato ; femoribus basi iufuscatis." On Aquatic Carnivorous Coleoptera or DytiscidcB. 7S9 " Cette espece, tres voisine du Hydrop. lituratus, Fab., pourrait, a la viie simple, etre confondue avec elle, mais, a la loupe, on voit que sa ponotuation beaucoup moins forte est aussi beaucoup plus dense et qu'elle est m6me presque imperceptible." 1345. Hydroporus bifasciatus, Macl., Trans. N. S. W., 1871, p. 121. Australia (Gayndah). " Length, 2 lines. Ovate, subconvex, covered with a close punctuation, and of a testaceous red colour. Head bordered in fi'ont, and with a very short, oblique, lightly-impressed line at the inner and anterior angle of the eyes. Thorax broad, short, narrowly margined on the sides, and broader behind than in front, with the anterior angles advanced, the posterior subacute, the base slightly bisinuate on each side, and a large patch of a dark brown colour on each side of the central lobe. Elytra broader than the thorax, rounded at the humeral angles and on the sides, and narrowed and rounded at the apex, with a very zigzag, black fascia about the middle, extending from the suture to near the sides, and another of the same hue, and rather broader near the apex, extending from the sides almost to the suture, the two fasciae being joined near the suture, and nearly joined about the middle of the width. On each elytron may be traced an obsolete stria a little way from the suture, and also a number of small, round, obsolete- looking depressions. The tarsi of the males are black and much dilated, the third joint being the largest." This description appears quite applicable to Hyphydrus australis (No. 358), and I expect the name will prove a synonym thereof.— D. S. 1346. Hydroporus bifidus. Say, Tr. Am. Phil. Soc. IV, p. 444. Mexico (in a small river beyond Vera Cruz). " Elytra with a subsutural, impressed, punctured stria. Body, black ; head with much dilated indentations between the eyes ; a longitudinal honey- yellow line, more dilated before ; antennse yellowish, dusky at tip ; thorax with a submarginal honey-yellow band before having three prooe.sses, one in the middle, and one, rather more dUated, on the lateral margin, not reaching the posterior edge ; elytra with a very distinct, punctured, impressed, subsutural stria, and about two other hardly obvious ones near the middle ; bifid yellowish lines at base near the tip ; feet, dark honey-yellow. Length less than one-fifth of an inch." This is perhaps near Hydroporus sequinoctialis, Clk. (No. 525.) — D. S. 1347. Hydroporus boristhenicus, Hoch., Bull. Mosc, XLIV, p. 233. Europe. " Long. 2^2^ lin. Diese art hat ihre nachsten Verwandten an H. 12 pustulatus und H. depressus, Fab., (fee, etc. Von alien diessen unterschiedet ihn sogleich bei fliich tiger Vergleichung, die liinglichere, von der Mitte nach vorn etwas, nach hinten stark verjungte form, cUe hoher gewolbten Elugeldecken, und das auf den Seiten starker abgerundete Halsschild, mit breitem schwarzem Saume am Vorderrande. Die Zeichnung der Fliigeldecken, zwar iihnlich den beiden Erstgenannten, ist jedoch auch wieder sehr verschieden " " Im Mai Monat im Dneper haiifig." I think this will prove to be a variety of Dytiscus dejoressua (No. 472). — D. S. 1348. Hydroporus caliginosus, Lee, Agass., Lake Sup., p. 215. North America. " Ovalis, minus convexus, niger nitidus, minus subtiliter punctatus, sparseque pubescens, thorace lateri- biis obliquis vix rotundatis, disco obsoletius punctato ; elytris basi vix conspicue angustatis, apice oblique attenuatis : antennis palpis pedibusque I'ufis. Long. "12." " More convex than the following (H. tartaricus), less parallel and more acute behind : the punctures of the elytra are much larger and more distant." 513 790 On Aquatic Carnivorous Coleoptera or Dytiscidce. According to a specimen recently sent to me by Dr. Leconte, this is closely allied to H. occidentalis (Xo. 553), but tlie surface is more opaque, the punctuation of the thorax is more distiuct, and the front tarai ai-e broader. — D. S. 1349. Hydroporus carbonarius, Clk., Tr. Ent. See. 3ra ser. I, p. 423. China. " Oralis, penitus cii-cularis, depressus, punctatus, cai-bonarius, nitidus ; capite subtUissime punctato, nifulo ; thorace antice emarginato, lateribus oliliquis rotundatis, basi subsinnato, ad medium late angulato, punctato, punctis crebris et distinctis, nigro, ad latera sub-nifulo ; elytris brevibus, haud punctato striatis, punctatis ; ad latera obscure marginatis, nigi-is, corpore subtus rufo-fusco ; antennis pedibusque rufis." ""Var.,fusco-brunneus, insulam Javam habitat. Long. corp. 1 lin. ; lat. |- lin." " The above diagnosis is dra^vn up from an example which Mr. E. Adams took in Danes Island, Chiua, in 1848." This is to be classed in the genus Hydrovatus ; the variety mentioned from Java is probably not the same species. — D. S. 1350. Hydroporus charlotti, Clk., Ann. Nat. Hist., p. 182. Mexico. " Ovatus, subelongatus, punctatus, flavo-fen-ugiueis ; elytris rufo-flavis, lineis obscuris tribus aut quatuor fuscis ; antennis inifo-testaceis. Long. corp. 1 lin., lat. ^ lin." " The species very closely resembles a pale variety of H. affiuis, Say ; the species before us is larger, a trifle more parallel in form, the longitudinal markings of the elytra are less distinctly de- fined, and the punctures on the elytra are less distinct." I should think this is very likely to prove the same as Hydroporus affinis (No. 318). — D. S. 1351. Hydroporus cleopatra;, Peyron, Ann. Soc. Fr. 1858, p. 397. Syria. " Ovatus, crassus, convexus, punctulatus, nitidulus, ferrugineus, thorace antice et postice nigiicante ; elytris confuse nigro-vittatis ; thoracis lateribus obliquis ; elytris apice attenuatis, pimctis nonnullis majoribus signatis. (Div. capite antice marginato.) Long. 4^, lat. 2^ m.m." " Ovale, epais et convexe, assez luisant, ferrugineux. Tete finement pointill^e, rebordee en avant. Prothorax etroitement marqu6 de noir au milieu du bord anterieur, et ayant a la base une tache de meme couleur 6chancree en avant ; il est faiblement pointille et se prolonge assez fortement en arriere, au milieu en pointe mousse ; ses cotes sont oliliques. Elytres attenuees, arrondies a I'extremit^, a ponctuation fine et bien marquee, formant une reticulation, avec quelques points un peu plus gros ; marquees en outre, au tiers environ de leur largeur a partir de la suture, d'une strie peu sensible disparaissant avant I'extremit^. Elles ont la base, la suture et deux bandes longitudinales coudees a leur extremite posterieure noires ; la tache de la base est assez 6troite et en occupe la moitie voisine de la suture ; celle ci est r^unie a la basale en avant et un peu dUatee en arrifere ; la premiere tache part de I'epaule, qu'elle ne touche pas ; se dirige d'abord un peu en dedans et ensuite en dehors, ou elle s'arrSte a peu pres aux deux tiers de la lougeur, en se dilatant d'une maniore arrondie vers le bord exteme qu'elle ne touche pas ; la deuxieme partant du milieu de I'elytre vers le quart anterieur descend en droite ligne jusqu' aux trois quarts de la longeur, oii elle est sinuee et dilat^e ext6rieurement en s'arrondLssant juste au dessous de la dilatation de la premiere bande. Ces taches sont tr^s confuses et souvent se rdunissent toutes entre elles, a part la tache basale qui panut constamment separee des dorsales." " II doit etre place aupres de 1' H. reticulatus. Fab." This is I should think a species of Ccelambus, near Hydroporus musicus (No. 390). — D. S. 1352. Hydroporus collaris, Hope, Proc. Ent. Soc. Lond. 1841, p. 48. Australia. " Nigro-piceus, punctatus ; thorace medio convex©, lateribus utrinque fortiter depressis ; elytris subtiUssime punctulatis piceis, corpore infra pedibusque concoloribus. Long. lin. 1|, lat lin. J." I can add nothing to the information as to this species given by Claik, Journ.'Ent. I, p. 412. D. S. On Aquatic Carnivorous Coleoptera or Dytiscidas. 791 1353. Hydroporus compunctus, Woll., Col. Atlant. App. p. 11. Canary Islands. " Ovalis, nitidulus, alutaceus, profunde sed baud dense pimctatus, parce cinereo-pubeseens, nigro- piceus ; capite omnino sed prothorace elytrisque ad latera indistincte nifesoentiorlbns ; prothorace parum insequali (postice late Lrregulariter impi'esso) ; elytris lineis tribus (una sc. juxtasuturam vix punctata, et duabus exterioribus e punctis sat magnis compositis) notatis ; antennis pedibusque rufo-ferrugiueis. Long. Corp. lin. 1|." " It is ratber smaller, convexer, and more oval tban tbe H. xantbopus, and very much more coarsely (and a little more sparingly) punctured ; its head and sides (at any rate of tbe protborax, which is also more deeply branded transversely behind) are more rufescent ; and its elytra are more distinctly im- pressed with an obscure longitudinal line (or wide, shallow depression) parallel to the suture, and the two usual series of punctures externally." 1354. Hydroporus contractulus, Mann., Bull. Mosc, 1852, II, p. 304. Sitka. " Breviter ovatus, subdepressus, ferrugineo-testaceus, subnitidus ; thorace dorso obscuriore infuscato, undique subtiliter punctulato, medio tenue canaliculato, serie punctorum majorum intra marginem apicalem notato ; elytris crebre punctulatis. Longit. 1 J lin., latit. -g- lin." "Habitat in insulae Sitkhse aquis rarissime, D. Holmberg." This name is not alluded to by Crotch in his " Ile^'ision of the North American Dytiscid» ;" it perhaps represents a species of Hydroporus neai- D. tristis (No. G02). — D. S. 1355. Hydroporus coquerelii, Fairm., Ann. Soc. Fr., 1869, p. 186. Madagascar. " Long. 3 m.m. Breviter ovatus, crassus, convexus, valde punctatus, nitidulus, rufo-testaceus, capite marginato valde impresso, prothorace medio infuscato, elytris fascia lata suturali et fasciis latis trans- versis, sinuatis, fuscis punctLsque fuscis ad humeros, aut fusco-nigris, fascia antica sinuata macvdaque subapicaU testaceis." " En ovale tr§s court, convexe, d'xm roux testace brillant. Tete ayant une large impression assez pro- fonde, rebordee en avant. Corselet densement et finement ponctue, un peu plus fortement a la base; disque plus ou moins noiriitre. Elytres courtes, arrondies en arriere, tr4s-ponctiiees ; tantot ayant une lai^e bande suturale d'un Virun mat avec deux fascies transversales de meme couleur, dentees, et quel- ques taches vers les epaules, tantot d'un brun noir avec une tache anterieure dentee et une tache sub- apicale d'un roux testace." " Forme et coloration de I'insequalis, mais plus grand, plus large, et remarquable par I'impression qui occupe tout le milieu de la tete." This description seems quite applicable to Hyj)hydi-us impressus, ELlug. (No. 346), and I believe the name \vill prove a synonym of that species. — D. S. 1356. Hydroporus cribrateUus, Fairm., Ann. Soc. Fr., 1880, p. 248. Algeria. "Long. 3 m.m. Oblongus subparallelus, depressiusculus, nitidus, luteo-testaceus, elytris piceo- testaceis, margine luteo-testaceis ; capite baud distincte pimctato, valde biimpresso ; prothorace basi, antice tantum angustato, lateribus a medio leviter arcuatis, margine postico medio obtusissime angulato, et utrinque obsolete sinuato, dorso baud sensim punctato, ante basin linea transversa leviter impresso ; elytris oblongis, basi parallelis, ante apicem tantiun attenuatis, apice acuminato, graciliter spinoso, dorso sat dense punctatis, utrinque linea fortius punctata signatis." Biskra. " Ressemble pour la coloration, &. I'H. obsoletus, mais la forme subparallele le rapprocbe du productus, dont il differe notablement par la forme un peu plus courte, les elytres tres ponctuees et terminees chacune par une pointe aigue. L'unique individu de cette espece n' a peut-etre pas toute sa coloration ; il serait possible que les elytres fussent brunes avec le limbe clair." 792 On Aquatic Carnivorous Coleoptera or Dytiscidoe. 1357. Hydroporus cyprius, Regt., Aim. Soc. Fr. 1877, p. 352. Cjrprus. " H. discreto Fairni., viciiius, sed minus conve.\us, multo magis elongatus, oralis, liaiul parallelus, antice et postice magis attenuatus, in prothorace elytrisque plus minusve pubescens ; niger, vertice obscure ferrugineo; elytrorum lateribus et basi saepe vage fuscescentibus, epipleuris nigris; infra valdo profundeque, supra dense nee tani profunde punctatus ; pedibus totis rufo-ferrugLneis ; antennis sat crassis, ad basin testaceis, postea fusco-uigricantibus ; protliorace ante basin sulco transverse obsolete et utrinque fovea lata impresso. Long. 3^ — 3^ m.m." " Cette esp^ce appartient au gi-oupe nombreux et diiBcile des Hydroporus noirs. 11 est voisin de I'H. discretus, Fairm. ; mais il est moLnsconvexe, bea\icoup plus allonge, regulierement ovale, non parallele etpar suite bien plus attennu6 en avant et en arrifere. II est entirfement noir et plus on moins pubes- cent sur le corselet et les elytres ; le sommet de la tete est marque d'une tache transversale d'un ferrugineux sombre, les elytres ont souvent a la base et sur les cotes une teinte vaguement brunatre ; toutes les pattes sont d'un roux ferrugineux, les antennes un peu epaisses, testacies a la base, noiratres dans les deux demiers tiers. Tout le dessous du corps est convert de gros points enfonc6s tres-marqu6s ; tout le dessus est ponctue assez finement et densement, sur tout sur le corselet, qui est presque rugeux, et qui en outre presente, en avant de la base un sillon en forme d'accolade, termine de chaque cote par une fossette rugueuse et bi6n marquee ; les deux lignes de points enfonces des Elytres sont bien apparentes, tandis qu'elles sont a peine indiqules chez le discretus." 1358. Hydroporus decemsignatus, Clk., Ann. Nat Hist 1862, p. 176. Mexico. " Ovalis, ad apicem attenuatus, punctato-striatus, niger ; elytris flavo decemnotatis ; antennis testaceis ; pedibus fuscis. Long. corp. 2 lin., lat 1 lin." " Broadly ovate, compressed and attenuated towards the apex, punctate-striate, of a duU black colour ] head broad, impunctate, with two insulated depressions, one on either side of the inner margin of the eyes, in colour black, the basal line and also the apex being obscurely tinged with rufous : thorax broad, the lateral margin lieing much constricted towards the front, and in a continuous line with the lateral margin of the head ; the surface (under a high power) is obsoletely rugose ; parallel with the anterior margin is a line of faintly impressed punctures ; in colovir black, with a medial circular spot of suffused rufous (in a second example there is a distinct trace of a similar suffused rufous marking near the margin) : elytra broad, attenuated towards the apex, with three lines of faintly impressed punctures — one near the suture, another medial, and a third at some distance from the lateral margin ; the surface is of a dull black colour, with five markings of flavous on each elytron — one at the base, transverse and parallel to the margin (sometimes continued at the shoulders in a line parallel to the lateral margin) ; the four others are smaller, of equal size, in form either subcircular or somewhat quadrate ; of these, two are near the lateral margin, one is situate at the apex, and a fourth medially near the suture ; abdomen and underside fusco-rufous, sometimes almost black : antennas testaceous : legs the anterior rufo-testaceous, the posterior fusco-rufous." I think this may prove to be a colour variety of H. roffi, Clk. (No. 1424). — D. S. 1359. Hydroporus delectus, Woll., Cat. Col. Can. 1864, p. 76. Canary Islands. " H. oblongus, minute punctulatus, tenuiter pubescens, niger prothorace ad latera dilute testaceo et oblique subrecto ; elytris utrinque lineis tribus latis interruptis testaceis, postice valde abbreviatis, ornatis ; antennis ad basin pedibusque piceo- testaceis. Long, coi-p. lin 1 — IJr. Very closely allied to the European Hydroporus flavipes, but I think, nevertheless, really distinct. . . . Rarissimus." 1360. Hydroporus depressicollis, Rosenh., Thier. Andal., p. 50. Spain. " Ovalis, depressus, rufo-piceus, opacus, densissime punctatus, tenuissime pubescens ; prothorace deplanato, lateribus parum rotundato et sub-elevato, elytris medio longitudinaliter deplanatis, sutura costisque tribus elevatis, duabus exterioribus obsoletis. Long. 1 j lin., lat. 1 lin." 0)1 Aquatic Carnivorous Coleoptera or Dytiscidce. 793 " Von der grosse des H. platyiiotus, aber von anderer form, farljp, punktirimg. Dem H. opatrinus iind liispanicus ain meisten iihnlich, sehr ausgezeiclinet durch flaclien Korper, sehr diclite punktirimg, durch welche der ganze Kafer matt erscheint, braunrothe farbe, sehr flaches lialsschild, welclies seitlich nur sehr wenig gerundet und fast gerade ist. Auf den fliigeldecken sind die aiisseren rippen nur kurz, die innerste sehr stark, die naht ebenfalls kielartig erhaben, der Raum zwischen dieser und der ersten Rippe niiildeuartig ausgeflacht. ..." " Bei Algeciras in fliessendem wasser im Marz gesammelt ; ich besitze mir ein einziges exemplar." This appears to be a species of Deronectes allied to Hydroporus bicostatus, Schm. — D. S. 1361. Hydroporus dichrous, Melsh., Proc. Ac. Philad. II, p. 28. North America. " Dusky, finely punctured, slightly pubescent ; head and thorax rufous ; body beneath black. — Hardly 2 L long, 1 1. wide. Pennsylvania." " Body ovate, finely and densely punctured, and slightly pubescent : head dull rufous, with an oblique shallow indentation each side between the eyes, which are black : thorax colour of the head, with the middle of the anterior margin dusky ; much and finely punctured, particularly the posterior margin and sides ; the latter slightly rounded : elytra dark reddish-brown, paler towards the sides ; finely and densely punctured, and slightly pubescent ; apex acutely rounded : antennae, palpi, feet, pleursu and epipleurse, rufous : venter and pectus black, distinctly punctured, the former with three or four lateral rufous spots." " Var. — Larger ; head tinged with black ; thorax nearly the colour of the elytra." This is placed by Crotch between H. modestus (No. 627), and H. Americanus (No. 619), and said (" Rev. N. Am. Dytisc." p. 394) to be " recognizable by its broad form, pointed behind, head and thorax often rufous, punctuation very fine." — D. S. 1362. Hydroporus discicollis. Say, Tr. Am. Phil. IV, 1834, p. 446. North America. " Reddish brown, somewhat sericeous, minutely piinctured, middle of the thorax without punctures." " Inhabits North West Territory." " Body entirely dark-reddish brown, with minute punctures ; head ; thorax with the disc impunctured, polished, and a little more convex ; elytra darker than the thorax, more obviously sericeous ; lateral margin a little paler ; spot at the tip dull yellowish ; post pectus black piceous. Length three- twentieths of an inch." Found during Long's expedition to the source of St. Peter's River. The species intended has not been recognized by Leconte or Crotch. — D. S. 1363. Hydroporus discoideus, Lee, Proc. Ac. Phil. 1855, p. 299. North America. " Latior ovalis fere depressus (minus nitidus) subtus niger, antennis pedibus corporeque supra testaceus, oapite lateribus et occipite infuscato ; thorace elytris angustiore macula magna basali infuscato, lateribus late rotundatis tenuiter marginatis cum elytris angulum formantibus, elytris confertissime punctulatis disco maximo communi infuscatis, sutura lineolisque anticis paucis pallithoribus, margine late testaceo relicto. Long. '15." " One female found at Fort Laramie. Broader and flatter than the allied species, and (in case the male should be more shining and more coarsely punctured) distinguished by the large basal spot of the thorax. The bead and thorax are moderately punctured ; the dark portion of the elytra is very well defined, and does not fade at all into the broad pale margin." According to Crotch (Tr. Am. Ent. Soc. IV, p. 389), this is a male of Hydroporus patruelis, Leo., (No. 399) but this opinion, in view of the fact that Leconte considered the indi^'idual described to be a female, requires confirmation. — D. S. 794 On Aquatic Carnivorous Cohoptera or DytiscidcB. 1364. HyJroponis dorsoplagiatus, Faiim., Auu. Soc. Fr. 1880, p. 247. Algeria. "Long. 2| ULDi. Oblongus, modice convexus, postice leviter attenuatus, fiiscus, capite, antennis protlioracisque margine latcrali rufo-testaceis, elytris fla-\-ido-testaceis, macula magna transverea, medio sita, postice lougc per suturam prolongata, marginem externum haud attingente, sed postice anguste pvoducta infuscata, pedibus rufesceutibus ; capite convexiusculo, ad oculos impresso ; prothorace brevi, antice leviter angustato, lateribus leviter arcuatis, utrinque striola laterali parallela signato, margine postico medio obtusissirae angulato, antice lineola transversa leviter impresso ; eljtris oblongis, postice a medio attenuatis, apice obtuse acuminatis, lajvigatis, utrinque lineis 2 leviter impressis et tenuiter punc- tulatis, apicem versus obsoletis ; pectore utrinque tenuiter pimctulato ct vage infuscato." " Voisin du sexguttatus, mais bien plus gi-and, plus allonge un pen plus parallele vers le milieu ; les ^lytres ne sont pas distinctement ponctuees, leur coloration est diiferente, la grande tache dorsale n'est pas nettement arrctee, ne se prolonge pas autant en avant et ne determine pas de taches jaunes en arriere, leur surface longituclLnale est aussi bien moins convexe." 13G5. Hyclroporus dubius, Aube, spec. 517. " Elongato-ovalis, depressiusculus ; capite testaceo ; thorace ad latera rotundato, testaceo, antice nigro, maculis duabus paulo oblique transversis, confuse nigro-brunneis, notato ; elytris castaneo-bninneis, cum margine exteriore angusto, sex aut septem lineolis plus minusve interi-uptis, confuse testaceo-ferrugineis, apice rotundatini attenuatis; abdomine nigro. Long. 5\ m.m., larg. 2| m.m." [.4 description, I.e., follows this diag^iosis]. " Je n'ai vu qu'un seul exemplaire de cet Hydroporus ; 11 fait partie de la collection du museum, ou il est indique comme ayant ete pris en Afrique, sans autre indication plus precise." Notwithstanding the locality given by Aube, I believe this will prove to be the H. ^dgilans, Woll. (No. 465).— D. S. 13GG. Hydroporus elegantulus. Boh., Ins. Caff. I, p. 249. Cafiraria. " Ovalis, modice convexus, nigro-seneus, nitidus ; antennis pedibusque flavo-testaceis ; prothorace crebre, evidenter punctulato, ad basin utrinque oblique canaliculato, margine vittaque media transversa, dorso interrupta, flavo-testaceis ; elytris profundius, seriatim punctatis, interstitiis vage punctulatis, disco uni-cobtatis, margine in£equaliter, fascia transversa intra basin maculaque parva, apicali, flavo-testaceis Long. 2, lat. 1 m.m." [This diagnosis is followed, I.e., hy a long descriptiori]. The species seems to be a Bidessus, near B. insignis (No. 252). — D. S. 1367. Hydroporus emilianus, Clk., Ann. Nat. Hist., 1862, p. 183. Mexico. " Ovatus, impubescens, punctatus, i-ufo-femigineus ; capite flavo, ad medium fusco-suffuso ; thoracis lateribus flavo-suffusis ; elytris punctatis ; antennis rufo-flavis. Long. corp. ^ lin., lat. f Hn." " Ovate, impubescent, tliickly and finely punctate, rufo-ferruginous : head transverse, impunctate, glabrous, in colour flavous, the inner margins of the eyes near the base being suffused with fuscous; thorax transverse, the sides subparallel and constricted in front ; the surface is glabrous and finely punctate, more distinctly near the base ; on either side of the middle, connected with the line of the base, is a short, well-defined, longitudinal fovea : elytra parallel, subattenuate near the apex, thickly but obsoletely punctate ; at the anterior margin (halfway between the humeral angles and the suture) is a short longitudinal fovea, corresponding in position to the thoracic fovea ; the smf'ace in colour is rufo- ferruginous or fuscous, the sides being more or less distinctly suffused with flavous ; abdomen and under- side dark fuscous ; legs flavous ; antennse rufo-flavous." This is perhaps a variety of Hydroporus afinis (No. 318). — D. S. Un Aquatic Carnivorous Coleoptera or Dijtiscidce. 795 1368. Hyclroporub evanescens, Boli., Ins. Caff. I, p. 252. Caffraria. "Subovatus, convexiusculus, flavo-testaceus, nitidus ; prothorace basi utrinque striola minima sub- obliqiia, in elytris continuata, impresso ; elytris confertim, evidenter punctulatis, basi, sutura late, postice in disco excurrente, ante apicem abbre\'iata maculaque magna, laterali, ovata, nigris. Long, f , lat. ^ m.m. " " E. minoribus. H. delicatulo non latior et dimidio brevior " Apparently a very minute species of Bidessus. — D. S. 1369. Hydroporus exilis, Boh., Ins. Caff. 1, p. 257. Caffraria. " Ovatus, convexiusculus, supra nigro-piceus, subtus-obscure ferrugineus ; antennis basi, palpis pedibus- que i-ufo-testaceis ; prothorace subtiliter, sat crebre punctulato, ferrugineo-marginato ; elyti'is obsolete, crebre pimctuhitis, lateribus obscure ferrugineis. Long. 1^, lat. 1 m.m." A description follows the above diagnosis. I am unable to form any opinion of value, as to the position of this species. — D. S. 1370. Hydroporus fau-maii-ei, Lep., Pet. Nouv. II, p. 53 : and Ann. Soc. Ent. Fr. 1876, p. cxxi. EiiroiJe. " Corselet a cotes arrondis, sans dilatation en avant, offrant sa plus grande largeur au milieu. Elytres sans ^chancrure en arriere de I'epaule, sans cotes careniformes ; forme ovale allonge ; courbure du corselet assez reguliere ; angles posterieurs plus ou moins marques, mais toujours sensibles. Lobe scutellaire du prothorax saUlant et aigu." The above is compiled from Leprieur's analytical table, I. c. ; we are also informed that this is Fairmaire's, Hydroporus vestitus, but that author's name is not adopted because of the prior H. vestitus, Gebl. I have little doubt however that the species is not a good one, but only a form of the variable H. mcestus, Faii-maire, (No. 456).— D. S. 1371. HydroporiLS fractQinea, Solsky, Fedt. Turkestan. II, 5. p. 134. Turkestan. " Ovatus, convexus, nitidus, puctatus, testaceus ; oculis, thorace media basi elytrisque, sat crebre, profunde punctatis, limbo angusto basali, sutura lineisque lougitudinalibus interruptis tribus, nigris ; pectore abdomiueque nigro-piceis, fortius punctatis. Long. 2J (elytr. \'ix 2), lat. 1^ m.m." \This is supple^nented by a description in Eussian.^ From the diagnosis it appears that this is a species of Coelambus similar to Ccelambus interruptus (No. 391), but the breast and the ventral segments are said to be pitchy-black. — D. S. 1372. Hydroporus fiyi, Clk., Ann. Nat. Hist. 1862, p. 181. Mexico. " Breviter ovatus, ad apicem subattenuatus, punctatus, niger vel ferrugineo-niger ; thorace fortiter punctato, undique ad latera antice transverse flavo-notato, linea basali attenuata constricta, elongata . elytris maculis quatuor magnis, his ad humeros subcircularibus, illis apicem vereus elongatulis. Long. corp. 1 Jin., lat. J lin." "... in general pattern it resembles at first sight H. decoratus, Gyll., and H. cuspidatus, Kunz. ; in form, size, and also in pattern, it approaches H. pumUio, Aube, but is much less coarsely punctate ; it is remarkable for the fine thread like character of its thoracic longitudinal strise, which are not short, and broadly defined, but elongated and narrow, as if formed by the scratch of a pin ; there are no traces of strise on its elytra, except in the scutellary region, where there is an abbreviated row of indistinct punctures near the suture : the surface of the elytra is sparingly covered with minute punc- tures : legs and antennae fuscous." This is a species of Bidessus, perhaps allied to Hydroporus pictodes, (No. 256). — D. S. TRANS KOT. DrB. SOC , N.S. VOL. II. ^ ^ 796 On Aquatic Carnivorous Coleoptera or DytiscidcB. 1373. Hydroporus gi-acilis, Welincke, Beil. Ent. Zeit. XVI, p. 136. Spain. " Elongato-ovalis, postice attenuatus, feiTugineus, spai-sim p\mctulatus. Long. 2 m.m." " Von langlicher form, rostroth, Kopf gross und ganz glatt. Halsscliild kurz uud breit, an den seiten etwas gerundet, ausseret sparsam und fein punktirt, am vorder- iind hinten-ande leicht gebraunt. Fliigeldecken lang gestreckt, nach hinten verschmalert, fein und sparsam punktirt, an der basis heller gefarbt. Die ganze unterseite nebst beine gelbroth. " Dem H. pygmajus Sell, am nachsten stehend, dui-cli die gleichbreite langliche form und durcli die feiue sparsame punktirung uutersclieiden." Found at Malaga, by C. P. de la Brulerie. 1374. HydropoiTis gravidus, Clk., Jouvn. Ent. I, ji. 413. Australia, (Port Essington). " Ovatus, latus, subdepressus, crebre punctatus, ater. Long. corp. 1^ lin., lat. 4 lin." " Broad, depressed, the surface is very thickly and coarsely punctured throughout, in colour black ; head broad, punctate ; the surface is unmarked by any fovea or depi'ession : thorax broad, the anterior angles rounded, the sides broadly marginate ; in colour black, the marginations being obscurely tinged with rufous, more distinctly near the basal angles ; elytra unmarked by any depression ; longitudinal line or stria pitchy black ; near the apex and also medially (at the extreme edge of the marginations) is an obscure rufous marking : antennae fuscous, the basal joints being rufo-fuscous : legs fuscous." This is a very distinct species of Antiporus, somewhat near H. blakei, Clk., (No. 434). — D. S. 1375. Hydroporus habelmanni, Wehncke, Ent. M. B. I, p. 76. Europe. [This description, copy of which was kindly sent to tne hy its author, has unfortunately been lost in transmission to tlie printers, and as iio copy of the work from which it is eictracted exists in Britain, so fa/r as I have been able to learn, cannot now be replaced.^ 1376. Hydroporus hansardii, Clk., Joum., Ent. I, p. 417. Australia (Moreton Bay). " Oblongo-ovatus, postice attenuatus, crebre punctatus, niger flavo-maculatus. Long. corp. 1^ lin., lat. f-l Un." " Oblong-ovate, parallel, somewhat attenuated at the apex, thickly and deeply punctate, black. Head with two small punctuations between the eyes, black, with a medial longitudinal line of dark i-ufous ; thorax broad, subparallel, in front the anterior angles rounded ; the surface is thickly p^mctate through- out, in colour nifo-fiavous, the anterior and posterior margins being nan-owly fuscous black ; the posterior marking consists sometimes of two submedial spots ; elytra subdepressed, thickly punctate, of a dull black colour, with the lateral margins and also six small longitudinal markings (three on either side of the suture) flavous ; the lateral margins, narrowly flavous continuously, are more broadly marked by three longitudinal flavous maculse ; legs and antennaa flavous." This is a Stemopriscus allied to S. clavatus (No. 361). — D. S. 1377. Hydroporus hottentottus, Har., Mun. Cat. (Hydroporus coUaiis, Boh., Ins. Cafl". I, p. 255.) CafTraria. " Hydroporus collaris ; oblongo-ovatus, convexiusculus, nitidus, niger; antennis basi pedibusque rufo- testaceis ; prothorace i-ufo-testaceo, medio nigro ; elytris piceis, evidenter, minus crebre punctulatis, disco antico stria tenui impressis. Long. 3, lat. 1| m.m." This diagnosis is supplemented by a longer description. I am quite doubtful as to the position to be assigned to the species. — D. S. 1378. Hydroporus humilis, King, Symb. phys. IV, t. 33, f. 11. SinaL " Nigro-piceus, antennis pedibusque testaceis, elytris piceis, basi obsolete testaceis. Long. lin. 2. Habitat in Montes Sinai aquis." On Aquatic Carnivorous Coleoptera or DytiscidoB. 797 " H. piano, cui simillimus et vaklc affinis, paulo minor. Oblongo-ovatus, sulitus sparsim punctatus, obscunis nigro-piceus. Caput vix pimctulatum, nigro-piceum, postice obsolete fermgineum. Antennae rufo-testaceae, unicolores, nee apice obseuriores. Thorax punctnlatus, nigro-piceus, margine lateral! teniiissime femigineo. Pedes rufo-testacei. Elytra subtiliter confertim punctata, picea ad basin rufo testacea." In the Munich Catalogue this is treated as a variety of H. lituratus (No. 569), but it appears to me doubtful whether it be so. — D. S. 1379. Hydroporus ignotus, Muls., Ann. Soc. Linn. Lyons, VII, p. 305 : op. Ent. XTI, p. 54. France. " Elongatus, subdepressus, nitidulus, parce griseo-pubescens, nigro-piceus, antennarum basi, pedibus. pronotiqiie lateribus rufo-testaceis. Elytris margine exteriore, macula antica marginali, duabus posticis submarginalibus, duabus oblongis anticis dorsalibus, testaceis. Pronoto utrinque breviter unistriato Long. 0-0024, larg. 0-001." " Environs de Lyon ; tres-rare. Dans les eaux de ITzeron et du Garon." " Cette espeoe se distingue du I'Hydr. varius, A ube, ])ar sa forme beaucoup plus allongee et plus dei>i-imee, par sa jjonctuation un peu plus serree, et par Tangle rentrant, forme par la rencontre des cotes du prothorax avec ceux des elytres, beaiacoup plus senti." The above diagnosis is followed by an excessively long, minute description of colour, itc. I think the insect will prove to be a variety of Hydroporus varius (No. 544). — D. S. 1380. Hydroporus inconspectus, Lep., Pet. Nouv. II, p. 53. Europe. " Corselet a cotes arrondis. Elytres sans echancrure en arriere de I'epaule, sans cotes saUlantes ; forme ovale allonge ; courljure du corselet assez reguliere, plus grande largeur de celui-ci a peu pres au milieu ; lobe scutellaire du prothorax saUlant mais obtus ou arrondi ; ponctuation du dessus grossiere ; taOle 3| a 6 m.m., sur 4^ m.m." This wUl, I have no doubt, prove to be a synonym of H. moestus, Faii-m. (No. 456). — D. S. 1381. Hydroporus incrassatus, Th. Op. Ent. IV, p. 366. Sweden. " Elongatus, fusco-testaceus, capite magno antice, antennis basi pedibusque testaceis ; prothorace apice quam basi pai-iun angustiore, lateribus leviter rotundatis, margine incrassato, disco Isevi, limbo elytrisque tenuissime pubescentibus obsoletius punctatis. Long. 1 lin." " Mas, imguiculis anticis insequalibus." " Statura fere H. umbrosi, sed minor, angustior, prothorace apice quam basi vix angustiore, margine lateraU, prsesertim antice incrassato mox distinctus ; ab H. pygmseo colore minus Iseto, capite majore prothoraceque discedens. Caput sat magnum, semicirculare, prothorace paulo angustius, fuscum, limbo anteriore testaceo, foveolis frontalibus sat magnis. Antenna? tenuiores, nigro-fuscsB, articulis primis totis, reliquis basi testaceis, tertio et quarto reliquis paulo angustioribus, baud transversis. Prothorax fortiter transversus, apice quam basi vix angustior, angulis anticis porrectis, basi medio minus late productus, angulis posticis rectis, lateribus leviter, aaqualiter marginatis, margine, prsesertim antice incrassato ; disco leviter convexo, Ijevi, glabro, limbo minus crebre, subtiliter punctato. Elytra prothorace quintuplo longiora, lateribus parum rotundatis, apice subacuminata ; disco leviter convexa, fere glabra, fusco-testacea, minus crebre, baud fortiter punctata. Corpus subtus fusco-testaceum, pectore obscuriore. Pedes testacei, femoribus posticis obscurioribus." 1382. Hydroporus inefficiens, "Walt., Ann. Nat. Hist., 1859, p. 51 (3rd Ser., Vol. III). Ceylon. " Testaceus, thorace maculis duabus posticis transversis nigris, elytris cinereis, glabris testaceo-strigatig basi nigris. Long, f lin." According to the type in the British Museum this is a species of Laccophilus. — D. S. 5 K 2 798 On Aquatic Carnivorous Coleoptera or Dytiscidce. 1383. Hydroponis infucetus, Clk., Ann. Nat. Hist., 1862, p. 180. Mexico. " Parallelus, jmnctatiis, nifo-femigineus ; cnpite flavo, ad medium j-ufo-fusco ; thovace iiifo-flavo elytris rufo-ferrugineis, ad basin flavo-lineatis, sutura fusca ; pedibus antennisque rufo-tiavis. Long. Corp. 14 lin., lat. 4 lin." " Parallel, .subovate, thickly punctate, rufo-ferruginous : head finely punctate, flavo-testaceus ; near the inner margin of the eyes is a longitudinal suflused marking of i-ufo-fuscous ; thorax transvei-se, finely punctate, rufo-flavous ; elytra subparallel, sufficiently robust, the sides near the anterior angles forming an obtuse angle with the sides of the thorax ; the siu-face is thickly punctate and rufo-ferruginous ; the anterior margin and also the longitudinal medial lines being flavous ; these lines, three or four in number, ai-e more or less obsolete ; the extreme apex is also flavous, and the sutural line narrowly fuscous j alidomen and underside black ; legs and antennse rufo-flavous." From my notes on the British Museum collection it appears that this is a species of Coelambus, near Hydroponis medialis (No. 401). — D. S. 1384. Hydi-oporus infaustus, Clk., Ann. Nat. Hist., 1^(32, p. 179. Mexico. " Oblongo-ovalis, subparallelus, antics sat obtusus, confertissime et obsolete punctatus, punctato-striatus, niger ; capite brevi, inter oculos undique late et obsolete depresso, punctatissimo, nigro, ad medium prope basin transverse rufo-notato ; thorace transverso, lato, ad latera tenuiter marginato, prope basin irregulariter transverse depresso, punctatissimo, nigro, ad medium nifo-notato ; elytris sat productis, ad apicem subacuminatis, subtiliter punctatissimis, punctato-striatis, nigris, ad latera obsolete rufo vel fusco notatis; pedibus rufo-testaceis,femoribusposticisnigro-suffusis; abdomine nigro. Long. corp. 21in.,lat. 1 lin." " Oval, somewhat produced, punctate-striate, black : head broad, on either side in front is an obsolete depression ; the surface (under a high power) is very finely and thickly punctate, in colour black ; near the Hue of the base a narrow transverse band of flavous is well defined ; thorax broadly transverse, the anterior margin excavated ; the sides subparallel and roiinded in front, very naiTOwly and evenly marginate ; the line of the base is broadly angulated at the region of the scutellum ; the surface is finely and thickly jninctate and medially somewhat rugose, with a row of minute pimctures parallel to the anterior margin ; near the base it is medially transversely depressed, in colour fuscous black, with a post-medial marking (sometimes almost obsolete, sometimes subcii-cular and suffused) of flavous ; elytra somewhat acuminated at the apex ; the shoulders are sufficiently prominent, thus fomiing an angle with the line of the margination of the thorax ; the surface is very finely punctate, with six deep punctate strise (more obsolete near the margins and apex) of a dull black colour, three or four obsolete markings of flavous being more or less distinct near the line of margination ; abdomen and underside black ; legs flavous, the apical joints being fuscous." This is allied to Hydropoi-us striatellus, Lee. (No. 494.) — D. S. 1385. Hydroporus infirmus, Boh., Ins. Caff. I, p. 2.51. Caffraria. " Oblongo-ovatus, supra convexiusculus, subtiliter crebre punctulatus, nitidus, jiiceus ; anteunis basi, palpis pedibus prothoraceque flavo-testaceis, illo macula magna basali, antice rotimdata, picea, notato, postice utrinque stria obliqua, in elytris continuata ; elytris tenuiter pubescentibus, margine lineolisque, duabus brevibus pone basin, flavo-testaceis. Long. H, lat. | m.m." [This diafjnosis is followed, I.e., hy a long desa'iption.'\ This is apparently a species of Bidessus allied to Dj'tiscus geminus (No. 269). — D. S. 1386. Hydroporus inquinatus. Boh., Ins. Cafl". I, p. 254. Caffraria. •Ovatus, convexiusculus, rafo-testaceus, lutidus ; capite medio transversim infuscato, subremote punctulato ; prothorace antice posticeque nigro, emlenter, subremote, medio subtiliter punctulato On Aquatic Carnivorous Coleoptera or Di/tiscid(e. 790 elytris sat crebre, mediocriter pmictatis, basi, sutura lineisque quatuor, 1 et 3 antice posticeque paullo, 2 antice valde, 4 brevi utrinque magis abbreviatis, lineolaque postica lateral!, subobliqua, nigris. Long. 5, lat. 3 m.m." [This diaffnosis is followed, I.e., bij a long descriptio7i.] I can form no clear opinion as to the species, it may possibly be a Herophydrus or CceJambus. — D. S. 1387. Hydroporus interpulsns, Walk., Ann. Nat. Hist., 3rd ser., IT, 18.58, p. 304. Ceylon. " Niger, crassus, capite, thoracis fascia latissima et elytrorum margine teniii luteo-ferrugineis. Long. If lin." According to the type in the British Museum this is allied to No. 370, Hyphoporus aper. — D. S. 1388. Hydroporus kingii, Clk., Ann. Nat. Hist., 1862, p. 178. Mexico. " Ovatus, subdepressus, puuctulatus ; tliorace nigro, marginibus flavis ; elytris rufo-fuscis ; pedibas antennisque rufo-testaceis. Long. corp. 1 J lin., lat. f lin." "Ovate, broad, subdepressed ; when seen under a high power, finely and sparingly punctate ; glabrous, darkly castaneous : head broadly transverse, impunctate, black : thorax broadly transverse, the sides rounded in form, the marginal line being continuous with that of the sides of the elytra and also of the head ; the anterior margin is straight, the anterior angles being subprominent ; parallel to the anterior margin is a row of minute punctures ; the surface generally is impunctate aud glabrous, with faint traces near the base of obsolete punctures ; in colour black, the sides being suffused more or less broadly with flavous ; elytra sufficiently robust, towards the apex subacuminated (but not so distinctly as in H. wardii) ; the surface is finely and somewhat sparingly punctate throughout, with a single medi-\l stria of closely arranged minute punctures on each elytron : abdomen and underside black : legs and antennas rufo-testaceous." This is allied to HydroiJorus vilis, Lee. (No. 641). — T>. S. 1389. Hydroporus laccophilinus, Lee., Proc. Am. Phil. Soe. 1878, p. 595. North America. " Ovate, depressed, pointed behind, brown, paler in front, darker behind ; epistoma not margined, head finely punctulate ; prothorax (i¥a*) rugose and finely punctured, narrower in front, sides oblique, finely margined. Elytra (J/as) strongly punctured, shining (Fem.) opaque, finely sparsely punctulate. nietasternum channeled for the posterior half of its length ; sparsely puuctui-ed in front ; abdomen coarsely punctured in both sexes. Length 2-6 m. m. ; '10 inch. " Detroit ; rare. The form is exactly that of a Laccophilus in miniature. The head and prothorax ■of the/em. are opaque and very finely and sparsely punctulate." 1390. Hydroporus lanceolatus. Walk., List. Col. Lord. p. 10. Wady Ferran. " Black, elongate, elliptical, slightly shining. Head, palpi, antennie and legs tawny. Prothorax in front with a broad tawny band, which is much excavated on each side of its hind border. Pectus with a tawny spot on each side. Elytra smooth, each with a large testaceous basal patch whicli emits two lanceolate streaks, with two testaceous dots near the suture, and with a large posterior elongated testaceous patch which extends to the tip and includes a black dot. Length of the body 2| lines." This is probably to be assigned to Deronectes. — D. S. 1391. Hydroporus latebrosus, Leo., Ann. Lye. V. p. 208. California. " Ovalis, convexiusculus, postice magis attenuatus, minus dense punctatus, piceus nitidus, thorace 800 On Aquatic Carnivorovs Coleoptern or Dijtiscidce. lateribns vix rotundatis, tenuiter niarginatis ; cum eljtris angulum baud formantibus, his ad medium thorace latioribus, lutescentibus, antennis pedibusque rufis. Long. '15, San Diego." Tlii-s is not alluded to by Crotch either in his check-list, or the " Revision of the N. American Dj-tiscidje."— D. S. 1392. Hydi-oporus lateralis. Boh., Ins. Caff. I, p. 255. Caffraria. " Ovatus, convexus, obsolete, crebre punctulatus, niger, nitidus ; antennis, palpis jiedibusque rufo- testaceis ; prothorace obsolete fernigineo-marginato ; elytris margine, fasciis duabus latis, transvereis, cum margine cohserentibus, introreum abbreviatis apiceque flaro-testaceis. Long. 2|, lat. 1| m. m." " H. picto parum longior sed latior." [Tflis diagnosis is followed hij a long description.'] I can form no idea as to where the species should be placed. — D. S. 1393. Hydroporus latipes, Brulle, Voy. d'orb. Col., p. 50. Aube, Spec, p. 445. South America (CoiTientes). " Elongato-ovalis, postice valde acuminata, convexa, supra undique valJe punctata; capite et thorace rufo-feiTugineis ; elytris nifo-piceis. Long. 6, larg. 2j m.m." [Avhe, 1. c, supplements the above diagnosis viith an ample description, and he refers the species to the genus Celina.'\ 1394. Hydroporus longulus, Mulst., Ann. Soc. Linn. Lyons. YII, p. 305. (op. Ent. XII, p. 52.). France. " Oblongus, leviter convexus, subnitidus, parce subtOissime gi-iseo pubesceus, vertice, antennis pedibus- que rufo-testaceis. Capite parce subtiliter, pronoto dorse parce, lateribus densius, elj^tris sparsim fortius, punctatis ; his prseterea punctis majoribus seriatis, bi-impressis. Long. 0'0030., larg. 00014." " Mont Dore, montagnes du Lyonnais, du Dauphing et de la Provence. Dans les eaux vives." " Cette espfece est bien voisine de I'llydr. nigrita, F. ; mais elle est un peu plus graijde, plus allonges, pliis brillante. Ses dlytres sont moins coiu-tes, moins ai-rondies sur les cotes, presque parallfeles, surtout chez les individus de la Provence." [T/ie above diagnosis is followed by an extremely long description.] The species is probably v(iry closely allied to H. nevadensis, and H. celatus, (Nos. 632, and 633). — D. S. 1395. Hydroporus lucasi, Reiche, (confusus Lucas. Exp. Alg. Ent., p. 96. pi. 11. f. 4). Algeria. "Long. 5 m.m., lai-g. 2 m.m. i. H. ovalis, convexus; capite nigi-o, subtilissime punctulato, piloso ; elj'tris fulvo-fen-ugineis, pilosis in medio macula atra irregulariter omatis ; corpore atro ; pedibus fernigineis." " Cet Hydropore ressemble beaucoup a I'H. lituratus, avec lequel il ne pourra utre confondu a cause de sa taille, qui est beaucoup plus gi-ande, et des taches que presentent les 61ytres, qui sont differem- ment dispos6es." Alsriers, Constantine. The figure, i c, is very inferior, but shows the elytra to be largely brown, with black marking about the suture. — D. S. 1396. Hydroporus magensis, Clk., Ann. Nat. Hist., 1862, p. 183. Me-sico. " Sat robustus, sub-pubescens ; prothorace ad basin transverse depresso, nigi-o, antice flavo ; elytris punctato-striatis. Long. corp. 14 lin. lat. J liii." " Ovate, broad, sufficiently robust, very finely and sparingly pubescent : head transverse, impunctate, glabrous ; below the inner margin of the eyes on either side is a minute fovea, and pai'allel to the line of the base is a minute longitudinal depression ; in colour black ; thoi-ax somewhat narrow, transverse ; on On Aquatic Carnivorous Coleoptera or DytiscidcB. 801 either side is a distinct, longitudinal, somewhat oblique fovea, extending from the middle to the line of the base ; the surface is thicklj^ punctate ; when viewed obliquely, a transverse shallow depression may be discerned near the middle, and also a minute punctured fovea near to the anterior margin ; in colour black, the anterior margin and sides being distinctly suffused with flavous ; elytra broad, robust, very finely pubescent ; beneath this pubescence are distinct punctures, and also a faintly punctate stria ; at the anterior margin, halfway between the sutui-e and the lateral angles, is a short depressed fovea, corres- ponding in position with the fovea on the thorax ; in colour a deep brown black ; abdomen and under- side black : legs rufous : antennae rufo-fuscous." This is a species of Bidessus. — D. S. 1397. Hydroporus masculinus. Crotch, Tr. Am. Ent. Soc. V, p. 74. North America. " Somewhat obovate, pointed behind, pale fulvous, breast and abdomen black ; head very finely puac- tulate ; thorax short, transverse, sides straight, base margined with black ; finely and rather closely punctulate ; elytra thickly and finely punctulate, pale yellowish, with the suture and four narrow lines black (the fii-st and third not quite reaching the base). Mas, anterior claws much elongate, deformed, subequal, the external one flattened. L. 4'75 m.m." "Lake Labache; very distinct by the male characters; the thii-d joint of the anterior tarsi is also feebly bilobed and the claw joint is large and hardly longer than broad." This is a very distinct species of Ccelambus, and may be placed near Hydroporus nubilus (No. 403). — D. S. 1398. Hydroporus melancholichus, Motsch., Schrenck Reise, 18(50, p. 100. (Hydroporus lugubris, Motsch., Bull. Mosc, 1845, IV, p. 353, pi. 6, f. 1). Kamtschatka. " Oblongo-ovatus, subdepressus, niger ; thorace transversim impresso ; hoc basi elytrisque dense punctatis, ultimis parce pilosis ; antennarum basi, elytrorum margine reflecto pedibusque rufo-piceis. Long. 1| Hgn., larg. 1 lign." " II ressemble un peu au H. planus, mais il est plus etroit. La tete est transversale avec deux impressiones arrondies entre les yeux, et \ine troisieme moins profonde sur le front. Le corselet s'elargit vers les elytres et presente vers la base une impression ponctu^e. Les 61ytreg sont un peu plus larges que le corselet, en ovale allonge comme la base de ce dernier, la pubescence est peu epaisse ; la portion reflechie des bords lateraux, la base des antennes et les pattes sont roussatres. Le dessous du corps est noir." 1399. Hydroporus mcestus. Walk., List. Col. Lord., p. 10. Waddy Ferran. " Black, elougate-oval, slightly shining. Head with a large reddish spot in the disc. Elytra smooth ; each with three testaceous spots at the base, with two indistinct streaks in the disc near the base, with. a testaceous costal streak proceeding from the base and ending in a patch at nearly one-thii-d of the length, with an elongated testaceous dpt near the suture at half the length, with three posterior elongated testaceous dots, one near the suture, two subcostal and near a testaceous costal line ; legs red. Length of the body 2f lines." This name is in prior use for another species. I have not identified Walker's description with any species known to me ; it is probably a Deronectes. — D. S. 1400. Hydroporus monUicomis, Sahl., not. fenn., XIV, j). 154. Russian Lapland. " Breviter ovatus, depressus, nitidus, niger, palpis, antennis, pedibus apiceque elytrorum ferrugineis - c.ipite basi rufo-piceo ; antennis medio iucrassatis, articidis subglobosis ; prothorace angulis posticis acutiusculis elytrisque parce subtUissime punctatis, subglabris. Long. 1|^ lin." S02 On Aquatic Carnivorous Coleoptera or Dytiscidoe. " Vac. b. : elytris macula humerali piceo-rufa notatis." " H. V>revi, Sahl., atfiuis, seJ paullo major, puuctiiru multo subtiliore et remotiore, antennis medio crassioribus coloreque facile distinguendiis. Caput pai-vum, lave, foveolis anticis distiuctis parvulis, nigrum, vertice anguste rufo-piceo ; palpis paUide ferrugineis, articulo ultimo apice fusco. AntennsB breviusculiB, fernigineoe, articiilis exterioribus Lnfuscatis, articulo quarto tertio distincte bre^-iore, subtransverso, quinto hoc fere duplo longiore et multo crassiore, subgloboso, 6-7 hiuc asqualibus, 8-10 sensim angustioribus et brevioribus, ultimo elongate, decimo paulo longiore, apice acuminate. Prothorax longitudine duplo et dimidio latior, apicem versus fortiter angustatus, lateribus leviter rotundatis, distincte marginatis, anguUs anticis acutiusculis, posticis rectis ; supra le^*iter convexus, remote subtilissime, limbo paullo densius, pimctatus, niger, subnitidus. Elytra basi protboracis latitudine et lateribus cum illo continue arcuatis, humeris liaud prominulis, postice angustato-rotundato, supra modice convexa, omnium subtilissime remote ])unctu!ata, seriebus punctorum majorum le'V'itcr impressLs, nigra, nitidula, subglabra, apice late indeterminatim ferruginea vel picea. Corpus subtus nigrum, parce minus profimde punctatum, prostemo baud tuberculato-prominido. Pedes toti rufo-ferruginei." " Rare in Russian Lapland, found near Kantalaks, 26tli June, and on the summit of Dschyn Hill, near Imandra (67° 30'), 6th Jul}-, 1870." 1401. Hydroporus multiguttatus, Regt. Ann. Sec. Fr. (V), VII, p. 351). Syria. " H. lucasi, Reiche, forma statu raque simUis, ovalis, dejiressus, postice parum attenuatus, ad apicem rotundatus, vix pubescens, subtus nigro-ferrugineus ; capite uigrieante, vertice clypeoque feniigineis ; prothorace infuscato, fere nigro, utriuque late, autice anguste rufo-marginato ; elytris fuscis, late ad basin et latera testaeeis, macuUs et lineolis testaceis pluribus confluentibus in disco et ad apicem omatis ; pedibus testaceo-ferrugineis ; antennis testaceis, articulis nltimis ad ajiicem paululum iufuscatis. Long. 4| m.m." " Meme forme et meme taOle que I'H. lucasi, Reiche, c'est^a-dLre ovale et tres-peu attenue en arriere, mais un pen plus deprimd et encore plus finement ponctu^-reticule sur les elytres. Tete finement ponctuee d'un bi-un fonc6 ; corselet borde de roux largement sur les cotes, etroitement en avant, convert d'lme pouctuation fine tr6s-sen-ee et egale, marque de chaque cote en avant de la base d'une fossette pen profonde mais sensible, reborde lateralement un jieu plus largement que chez le lucasi. Eh-tres d'un brun plus ou moins fence, largement testacees a la base, sur les bords et soaveut le long de la suture, marquees sur le disque de plusieurs taches et Hneaments testaces plus mi moins confluents, avec I'extremite plus ou moins de cette meme couleur ; elles sont couvei-tes d'une pubescence couchee tres- rare, tr6s-courte, et tres-facile a enlever ; epipleures d'\m testac6 pale. Dessous du corps d'un brun noiratre ; pattes rousses ; antennes testacees, avec I'extremite des derniers articles legerement rembruuie." Borak. 1402. Hydroporus mutatus, Har. (H. ruficeps. Boh., Ins. Cafl". I., p. 253). Port Natal. " Hydroporus i"uficeps : ovatus, convexus, nitidus, supra niger, subtus ferrugineus ; capite, antennis pedibusque nifis, hoc medio subremote, transversiui punctulato ; prothorace antice posticeque evidenter, sub-remote, medio trausversim, subtUiter rugoso-punctulato, lateribus indeterminate rufo-ferrugineo ; elytris sat crebre, mediocriter pxmctatis ; margine Lnflexo rufo. Long. 4i, lat. 3 m.m." " H. rufifronti latior, bre-s-ior, magis convexus." [This diagnosis is JoUorved, 1. c, by a long descrij>tiim.'\ The position the species should occupy is quite doubtful to me. — D. S. 1403. Hydroporus nicobai-icus, Redt., Reis. Novar. IT, p. 21. Nicobar Islands. " Oblongo-ovatus, pallide testaceus, capite thoraceque iiallidis ; thorace latitudine media duple bre^•ior, angulis anticis j'l'oductis, acutis, postice utrinque stria Vecta, in elytris coutinuata, inter strias obsolete On Aquatic Carnivorous Coleoptera or DytiscidcB. 803 punctatus et anguste nigi-o-marginatus ; elyiris fortiter punctatis tenue pubescentibus, fuscis, macula magna posthumerali obsoleta, dilutiori. Long. 9/10'", lat. elytr. 2/10 — 3/10'"." " Der korpev ist lang cifurmig, liinten zugespitzt, massig stark gewfilbt, braunlicligelb, der kopf iind das halsschild sind blassgelb, die flUgeldecken braun, die beine etwas dunkler als die unterseite. Der kopf ist halbi-und, selir flach gewolbt, nicht punktii't, der vorderrand etwas gewulstet. Das halsschild * ist mehr als dreimal so breit als lang, nach vorne sanft verengt, der vorderrand zwischen den weit vorepringenden, spitzigen vovderwinkeln gerade, der liinterrand nach ruckwarts in der mitte stumpf dreieckig erweitert, die hinterecken rechtwinkelig die oberfliiche flach gewolbt, nur hinten piinktirt und hier beiderseits mit einem kurzen, vertieften strichel, welches sich in doppelter lange auf der mitte der llLigeldecken wurzel fortsetzt, der theil des hinterrandes zwischen diesen stricheln sohwarzlich angelaiifen. Schildchen nicht sichtbar. FlUgeldecken viermal so lang als das halsschild, aber kaum breiter, an den schultern enge an das halsschild anschliessend, von der mitte angefangen allmalig zugespitzt, fein sparsam behaart, ziemlich tief und zart punktirt, die zwischen-ratime der punkte grosser als diese, die farbung braunlich niit einer grossen etwas heller durch-scheinenden, sich nach einwarts ziehenden makel hinter der schulter und einer zweiten, ebenso undeutlichen kleinen makel hinter der mitte am seitenrande." This is to be assigned to the genus Bidessus. — D. S. 1404. Hydroporus niger, Say, Tr. Am. PhU. II, p. 102. North America. " Black, villous, obscure, immaculate ; head and lateral margins of the thorax and elytra obscure rufous. Length more than three-twentieths of an inch. Body black, obscui-e, very numerous, minute, villous punctures^ hairs adpi-essed to the surface ; head obscui-e rufous, paler beneath, dusky each side of the front, a slightly indented spot each side 1 lefore instead of the imjjressed line and punctures ; antenuse dusky towards the tip of each of the terminal joints ; palpi, terminal joints blackish ; thorax black, very obscure rufous on each side, dorsal line none, elytra black, very obscure rufous each side near the base, strife or maculje ; epipleura I'ufous ; pectus and post pectus black ; feet rufous ; venter black, segments slightly piceous at-tip." This species name is not alluded to by Crotch in his " Ec^•ision of the North Amei-ican Dytiscidse." In the Munich Catalogue, it and H. punctatissimus, Aube, are considered identical. — D. S. 1405. Hydroporus notabilis, Lee, Agass., Lake Sup., p. 216. North America. " Elougato-ovalis, antice obtusus, postice oblique attenuatus, nigro-piceus pubescens, caj)ite punctulato antice posticeque testaceo, thorace dense punctvilato, obsoletius in disco, basi obsolete depressa, lateribus valde obliquis rotundatis, elytris elongatis, confertissime subtiliter punctatis, piceis, margine pallidiore, antennas tenuibus, cum palpis pedibusque rufis. Long. -21. One specimen. Black Bay." A male of this species recently communicated to me by its describei is allied to Hydroporus arcticus (No. 628), but has the thorax broader, and the basal joint of the front and middle tarsi remarkably large.-D. S. 1406. Hydroporas nudatus. Say, Tr. Am. Phil. IV, p. 444. Mexico, (in a small river beyond Vera Cruz). " Beneath black ; feet yellowish ; thorax and head on their discs yellowish ; elytra blackish with lines, and tip yellowish." " Head with numerous deep punctures, honey-yellow on the disc, blackish each side and behind ; antenuse pale yellowish, dusky at tip ; thorax with numerous deep punctures, more dense and obvious towards the base, honey-yellow, anterior and posterior margins dusky ; elytra brownish black, with numerous profound, approximate punctures, strias not distinct, but traces of two may be discovered near TBANS. ROT. DUB. SOC, N.S., VOL. II. 6 L 804 On Aquatic Carnivorous Coleoptera or Dytiscidce. the base ; about four more or less confluent lines at base, irregular ones each side and tip dull whitish yellow; beneath black, pectus yellow ; feet honey-yellow. Length over three- twentieths of an inch." This is perhaps a species near Hydroporus sequinoctialis, Clk. (No. 525). — D. S. 1407. Hydroporus obscurus, Bab., Tr. Ent. See. Ill, 1841, p. 14. Brazil. " Oblongo-ovatus, opacus, minutissime piinctatus, supra et subtus fuscus, thorace, antennis pedibusque flavis. L. I, lat. I lin." "Minute, oblong-ovate, opaque, fuscous both above and below. Head large. Antennaj yellow. Thorax yellow, transverse, short, broadly emarginate in front, sides rounded, posterior margins wavy, the disc slightly elevated transversely, and a deep abbreviated impressed line on each side behind. Elytra ovate, fuscous, the base and suture darkest, the margins and apex reddish, very minutely punctured, and slightly downy, an impressed line on each side at the base in continuity with that on the thorax. Body beneath slightly downy, fuscous, with the abdomen rather i)aler. Legs yellow." "Hab., Eio de Janeu-o." The type of this species appears to be lost from the British Museum ; the name is placed in the Munich Catalogue as representing the female of H. nitidus, Bab. (No. 313), H. Miei-si, Mun. Cat. but it is very doubtful whether that is con-ect. — D. S. 1408. Hydroporus obtusipennis, Sahl., Not. Fenn. XIV, p. 146. Russian Lapland. " ObloEgo-ovalis, modice convexus, tenuissime pubescens, punctulatus, piceo-niger, antennis basi pedibusque ferrugineis, femoribiis, capite antice posticeque, prothoracis elytrorumque lateribus piceis ; capite magno, impressionibus distinctis, prothorace lato, angulis posticis subrectis, lateribus subparallelis, postice obtusis. Long. 2| lin." " Mas : tarsis anticis articulis tribus basalibus fortius dilatatis, unguiculis valde elongatis, subrectis, subKqualibus, basi dente obsoletissirao armatis." " H. lapponum, Gyll., valde affinis, sed distincte major, paullo convexior, prothorace majore, angulis posticis minus obtusis, el3'tris postice minus angustatis, pubesccutia paginte superioris tenuiore, punctura totius fortiore stnictiiraque unguiculorum anticorum in mare distinguendus. Ab H. rufifronte, Duft., et arctico, Thoms. , prothoracis elytrorumque forma satis differt. Caput latum, subconvexum, remote sub- tilissime i^unctatum, nigro-piceum, antice late margineque basali piceo-rufis, impressionibus anticis satis distinctis ; palpis ferrugineis, ai-ticulo ultimo piceo. Antennw piceo-nigi-as, articidis duobus basalibus, totis, 3-6 basi pallide ferrugineis, articulo quarto et tertio »qualibus, quinto distincte breviore. Pro- thorax longitudine plus quam duplo latior, apice quam basi parum angustior, lateribus leviter rotundatis, tenujter marginatis, angulis anticis productis, subacutis, posticis rectiusculis ; supra leviter convexus, niger, nitidus, postice transversim fortius impressus, disco Itevi, limbo omni confertim punctulato, parce tenuissime pubescens, lateribus obsolete indeterminatim rufo-piceis. Elytra basi prothorace vis latiora, pone humeros leviter ampliata, deinde lateribus subparallelis, postice conjunctim late rotimdata, ante apicem obsoletissime sinuata, supra modice convexa, subtiliter punctulata, seriebus punctorum majorum nullis, parce tenuissime griseo-pubescentia, nigi-o-picea, nitida, hiteribus dilutioribus ; epipleuris iiiipressis, distincte marginatis, remotius punctatis. Corpus subtus nigrum, subtiliter et distincte jmnctulatum, parce tenuissime pubescens. Pedes ferruginei, coxis femoribus tarsisque apice infuscatis, unguiculis albido-testaceis. " "Very rare, found in stagnant water on a moss at Ponoj in Russian Lapland (67°) 13th August, 1870." 1409. Hydroporus opacus, Wehncke, Berl. Zeit XV, p. 163. Lapland. " Oblongo-ovalis, niger, opacus, parcius pianctulatus, elytris fuscis, antennis pedibusque ferrugineis. Long. 1| lin." On Aquatic Carnivorous Coleoptera or Dytiscidce. 805 " Von gestalt des H. geniculatus, aber etwas kleiner und durcli die lielleren fliigeldecken iind beine iinterschieden. " Kopf pecbbraim, sehr fein imd sparsam piinktirt, FlUiler rotbbraun. Halsscbild schwarz, die seiten feiu und nicbt sehr dicht, auf der scheibe nur eiiizeln punktirt. Fliigeldecken dmikelbraun, nach den seiten zu heller, fein punktirt. Beine rotlibraun." It is doubtful whether this be a good species ; it may prove a variety of H. morio (No. 598) or one of the closely allied species. — D. S. I-IIO. Hydroporus oppositus, Say, Tr. Am. Phil. Soc. II, p. 102. North America. '' Blackish ; head and base of the thorax ferruginous ; elytra with six whitish marginal spots or sub- fascia. Length rather less than three-twentieths of an inch. Body with very numerous, villous, minute punctures, hairs adjjressed to the surface ; head rufous or ferruginous, four or six indented, frontal, distant punctures ; thorax ferruginous, black at tip, about three indented punctures placed transversely ; elytra black, each with an irregular humeral spot, another placed upon the margin beliind the middle, and a third apical one yellowish, edge yellowish ; post pectus and venter blackish or deep piceous ; pectus and feet yellowish-testaceous." This was rather doubtfully identified by Leconte as H. proximiis, Aub6, (No. 513), but the description appears to me inapplicable to that species. — D. S. 1411. Hydroporus orientalis, Clk., Tr. Ent. Soc. Loud. 3 ser. I, p. 423. China (Danes Island). " Ovalis, penitus circularis, depressus, punctatus, carbonarius, nitidus ; capite subtiUssime punctato, rufulo ; thorace antice emarginato, lateribus obliquis rotuudatis, basi subsinuato, ad medium late angulato, punctato, punctis crebris et distinctis, nigi'O, ad latera subrufulo ; elytris brevibus, hand punctato-striatis, punctatis ; ad latera obscure marginatis, nigris, corpore subtus inifo-fusco : antennis pedibusque rufis. Long. corp. 1 lin. ; lat. | lin." This is a Hydrovatus, near H. tinctus (No. 200). — D. S. 1412. Hydroporus pectoralis, Motsch., Bull. Ac. Pet. I, p. 294. Western Siberia. " Voisine du H. nigro-lineatus ; ressemble par ses lignes noii-es plus fortes et plus longues plutot au nigro-lineatus qu'au flaviventris, mais se distingue du premier par une taille d'un tiers plus considerable^ La tete et le corselet sont lisses ainsi que les elytres, les lignes uoii-es y atteignant presque la base, surtout les seconde et quatrieme. La poitrine est noire dans les deux sexes, mais I'abdomen enti^rement testace chez la femelle. Chez la Fern, du nigro-lineatus I'abdomen n'est testace qu' a la base, le reste est noir." This insect, found in the salt lakes of Western Siberia, is no doubt a species of Coelambus. — D. S. 1413. Hydroporus persimDis, Crotch, Tr. Am. Ent. Soc. IV, p. 395. North America. " Very close to H. collaris, but longer, more parallel, thorax smooth, elytra more sparingly punctate ■without traces of the dorsal strife, humeral angles less prominent. Length '15 inch. Canada." An individual of this species sent recently to me by Dr. Leconte, appears to be closely allied to H. oblitus and stagnalis (Nos. 638 and 639), but is a little more elongate and dejiressed, and has the upper surface rather more punctate. — D. S. 1414. Hydroporus piceus, Stepk, 111. Brit. Eut. II, p. 62. England. " Oblongoiceis, hoc linea nigra lateral! ; supra vix pubescentia, minus crebre, subtiliter punctata, seriebus e punctis majoribus haud conspicuis. Corpus subtus nigrum, segmentis 3 primis lateribus sat crebre, minus profunda punctatis ; prosterno antice inter basin coxarum processu parvo palpos excipianta, instrncto. Pedes piceo-rufi." 1436. Hydroporus subtilis, Lee, Ann. Lye. V, p. 206. California. " Oblongus, postice subacutus, piceus, subtiliter punctatus, nitidus, capita parce punctulato, thorace antrorsum angustato, rvifo, antice posticeque nigiicante, lateiibus paulo rotundatis, tenuissime margi- natis, cum elytris angixlum vix formantibus, striola basal! profunda ; elytris macula quadrata jione humerum, altaraque marginal! pone medium rufis, stria suturali distincta. Long. -06, specimen unicum ad Sta. Isabel." According to a specimen recently communicated to me by its describer, this species is to be placed in Bidessus, group IV ; the elytra possess a rather obscure sutural line ; it may go near No. 261. — D. S. 1437. Hydroporus subtonsus, Lee, Proc. Ac. Phil., 1855, p. 297. North America. " Longior ovalis, parum convexus, parca pubescens, niger, ora rufescente, thorace lateribus, vix margi- natis mfescentibus cum elytris angulum obtusum formantibus, anguiis posticis rectis, disco parce subtilius, ad basin et latera distiactius punctato, elytris ssepe testaceo-piceis, modice punctatis, pedibus rufo-testaceis. Long. -125." " Lake Superior and Vermont. Resembles in appearance H. varians and H. puberulus, and likely to be confounded with them. H. varians is naiTower and more oblong, the sides being almost parallel at the middle, and is entirely glabrous. H. puberulus has the posterior angles of the thorax obtuse and very distinctly impressed. The elytra of the female are less shining and less deeply punctured than those of the male." This is placed by Crotch next to D. tristis (No. 602).— D. S. TKANS. ROV. DUB. SOC, N.S., VOL. IL 5 M 812 On Aquatic Carnivorous Coleoptera or Dytiscidce. 1438. Hydroporus subtruncatus, Faii-iu., Pet. Nouv., No. 151. North Africa. " Long. 4| m.m. Pnrcedenti (H. aciiminatello) simiUimus, sed elytris panic latioribus prothorace lateribus leviter arcuato, cum elytris evidenter angiilato, maculis basalibus hand impressis, elytiisque apice obHque sub-siiiuatis et extus aiigulatis distinctus." J should think this is probably H. clarki, Well. (No. 4C9).— D. S. 14.39. Hydroporus taiiricus, Motsch., Bull. Ac. Pet., 1860, I, p. 294. South Russia. " Una espece tres voisine du H. flaviventrLs habite la Tauride. Elle a la meme taille, les memes couleurs, mais les lignes noii-es sur les t'lytres sent plus avancees, et la quatrieme contigiie, de sorte qu'ici la suturale est la plus courte. Tete et corselet sans pouctuatioii distinote, le dessous du corps noir, avec I'anus testace. Mas. Je I'ai nomme Hydr. tauricus." Apparently this is a species of Coelambus, near Hydroporus flaviventris (No. 420). — D. S. 1440. Hydroporas tenellus, Clk., Tr. Ent. Soc, 1863, 3rd ser. I, p. 427. Java. "Oblongo-ovalis, attenuatus, apice acuminatus, nifo-fla-siis, impunctatu.s, nitidus ; capite nifo, impunctato ; thorace late transverse, antice subemarginato, lateribus sat rotundatis, leviter marginatis, basi (supeme viso) transverse, flavo, maculis transversis ad apicem obscure rufo-flavis ; elytris ad humeros thorace baud latioribus, ad apicem acuminatis, impunctatis, rufo-flavis, ad margines flavis ; pecUbus, antennis et corpore subtus flavis. Long. corp. lin. ^ ; lat. -j^ lin." This belongs to the genus Notomici-us, and is very closely allied to N. Irevigatus (No. 4.). — D. S. 1441. Hydi-oponis tetragrammus, Hoch., Chaud. En. Car., p. 223. Caucasus. " Oblongc-ovatus, convexJusculus, testaceus, pectore abdomineque nigi-is, elytris pallide testaceis, sutura lata, lineisque in singulo binis abbreviatis nigris, interiore apice orbicidato-dilatata ; thoi-acis basi utrinque striola minuta, in elytroram basi producta, valde impressa, stria suturaU Integra, Long. | ligne." " Ce joli petit insecte est a peu prfes de la grandeur et tout-a-fait de la forme du H. pygma;us, Sturm ; il est seulement plus convexe et se rapproche le plus du H. geminus. Fab. La ponctuation du dessus est la meme, et Ton retrouve les memes stries k la base du corselet, qui se prolongent sur celle des elytres qvioique moins que dans le geminus." " Vue par devant, la basede la tete et du corselet entre les deux stries, presente une ombre-noirati'e. Le dessin des elytres est caracteristique dans cette espece. Le fond en est d'un jaune-paille ; la suture entre les stries de la base, et deux bandes longitudinales qui n'atteignent ni la base ni I'extremite, assez larges, bien detex'minees, dont l'int6rieure, plus longue, se dilate en cercle post^rieurement et en dehors noires. Le reste comme dans le geminus." " Environs de Lenkoran." This appears to be a species of Bidessus very near to H. confusus, (No. 270), perhaps indeed a variety thereof. — D. S. 1442. Hydroporus thoreyi, Clk., Journ. Ent. I, 1862. p. 409. Australia, (Tarangoo). " H. ovatus, valde punctatus, iiifo-flavus ; thorace punctulato, nigro-marginato ; elytris rufo-fuscis, quinque flavis striis undique omatLs, subpubescentibus. Long. corp. H lin., lat. f lin." " Ovate, broad, thickly punctate throvighout, rufo-flavus : head impiinctate ; thorax very finely punctate ; when seen through a fine lens, somewhat more distinctly punctate at the base, nan-owly margined wth black : elytra very finely punctate, in colour rufo-fuscous, with five parallel longitudinal flavous lines extending from the apex to the base ; the surfxce when \'iewed obliquely, is seen to be finely clothed with pubescence ; legs and antennae flavous." I ^do not know any species like this ; it somewhat resembles our European Dytiscus ILneatus unctulate, disc nearly smooth, with a small black central mark and a linear fovea, base and apex faintly black ; elytra regularly elongate-ovate, closely and finely punctate 5 M 2 814 On Aquatic Carnivorous Coleoptera or Dytiscidce. throughout, each witli the suture (very narrowly) and three lines black, almost entire, a fourth line is broadly interrupted in the middle and at the apex. Mas, anterior tarsi short, broad, third joint deeply bilobed, external claw thickened, internal reduced to half the ordinary size, so as to appear rudimentary. Length 5 '5 m. m." " British Columbia, one male. Resembles H. parallelogrammus of Europe." This is a Coelambus resembling D. parallelogi-ammus, but much more finely and evenly punctured ; it may be placed near Hydroporus nubilus (No. -103). — D. S. 1448. Hydroporus vestitus, Gebl., Bull Mosc, 1848, III, p. 76. Siberia. " Oblongo-ovatus nigrescens, subtUissime coriaceus, griseo-subtomentosus, nitidulus, ore, antennis pedibusque luteis, thorace lateribus rotundato, late reflexo, linea transversa impressa, elytris linea longituduiali impressa. Long. 2 Un., lat. 1 lin." " Farum nitidus, tomento brevissimo, griseo adspersus ; statura H. opatrini, lU." " Er steht der H. opatrinus am nachsten ist aber fliicher, feiner punktirt, gliinzonder und anders gefarbt das lialsschild anders gebildet." Leprieur has made known that this is a distinct species allied to Hydroporus moestus (No. 456). — D. S. 1449. Hydroporus vitticollis, Boh., Ins. Caff. I, p. 256. Caflfraria. " Oblongus, parum convexus, nitidus niger ; capite antice, palpis, antennis pedibusque i-ufo-testaceis ; prothorace flavo-testaceo, postice late infuscato ; elytris obsolete, crebre punctulatis, maculis duabus lateralibus, tertiaque apicali, flavo-testaceis. Long. 1^, lat. ^ m. m." [This diagnosis isfoUowed by a long descrvption.'\ I have no idea what position the species should occupy. — D. S. 1450. Hydrovatus (Oxynoptilus) ferrugatus, Regt., Ann. Soc. Fr. 1877, p. Ixxix. Manilla. " Ovalis, fere rotundatus, vix postice attenuatus, sed fortiter acuminatus, creberrime punctatus, fortius in elytris, sxipra ferrugineus, ad latera vix diliitior, ad basin et suturam elytrorum %nx obscurior ; subtus ferrugineo-testaceus, pedibus conooloribus. Long. 2| a 2| m. m." \At p. 360, op. cit., this diagnosis is supplemented by a description.^ 1451. Hydrovatus homii, Crotch, Tr. Am. Ent. Soc. IV, p. 387. North America. " Extremely like H. cuspidatus, but twice as large, similarly coloured ; head shining, with a few punc- tures on the vertex ; thorax visibly but sparsely punctate ; elytra at the base (especially externally) very coarsely and closely punctate, with a deep submarginal groove : metastemum very coarsely punctate. Length -13 inch." According to a type recently communicated to me by Dr. Horn, this species is closely aUied to Hydrovatus major (No. 221), but is smaller, and has the upper surface rather more densely and less coarsely punctured, and the pale portion of the upper surface is more extended. — D. S. 1452. Hydrovatus maculatus, Motsch., Et. Ent. 1859, p. 42. India. " De la forme raccourcie du Hydrov. subrotundatus, raais deux fois plus petit et d'une couleur rousse sur la tete et le corselet, presque noire sur les 61ytres, on les c6t6s sont de teinte testac^e avec trois larges sinuosites et un point de cette meme teinte vers le milieu pres de la suture ; le bord post^rieur de la tete et du corselet, ainsi que le metathorax, sont brunatres ; antennes et pattes roussatres. Ponctuation sur les elytres tres fine et peu apparente, nulle sur la tete et le corselet qui sont tres luisants comme les premieres. Egalement du continent Indien." On Aquatic Carnivorous Coleoptera or DytiscidcB. 815 . 1453 Hydrovatus obscurus, Motscli., Et. Ent. 1859 p. 43. Oeylon. " Voisin du Hydro, seminarius, mais un peu plus grand, plus large, plus convexe et de couleur brnn-noiratre en dessus. La pouctuatiou siir les ely tres et le corselet est bien marquee, les c6t6s du corselet sont plus obliques, ce qui rend les angles posterieurs plus saillants. " There is in the British Museum a specimen, probaljly from Motschoulsky, of this species ; it appears closely allied to Hydi-ovatus fusculus ( No. 193 ) b\it is narrower and less punctured. — D. S. 1454. Hydrovatus punctipennis, Motsoh., Et. Ent. 1859 p. 41, India " Forme et couleurs du Hydr. obtusus, m. mais d'un tiei-s plus grand, et surtout plus large. Les 61ytres sont plus grossierement ponctues qne le corselet et fortement appendiculees a I'extremite. Du Continent de rinde. " 1455. Hydrovatus rufescens, Motsch., Et. Ent. 1859, p. 41. India. •' Ti-fes voisin de H. picipeunis, mais qui se distingue par une forme moins elargie an milieu des 61ytres, plus obtuse, en avant, une ponctuation plus fine sur le corselet et i)resque nulle sur les 61ytres, ou Ton distingue une strie pointillee vers le milieu de chacune. La couleur generale est un testace-roussatre, avec line rangee de points fonc6s le long du bord anterieur du corselet, etune autre de cliaque cote de la suture, qui est aussi de cette derniere couleur . L'extremite des elytres est assez sensiblement attenuee en pointe. Elle vient du continent oriental de I'lnde." According to a sjieciuien, probably named by Motschoulsky, in the British Museum, this is a large narrow, pale, very smooth, yellow species. — D. S. 1456. Hydrovatus seminarius, Motsch., Et. Ent. 1859, p. 42. India. " Tres voisin du Hydr. subrotundatus, dont il a la couleur rufescente, mais un peu plus petit et d'un tiers plus ^troit, ce qui lui donne un aspect oblong, assez semblable a celui du Hydr. obtusus, a I'exception cependant de I'extremitd des 61ytres, qui parait plus attenuee. II est tres luisant sur le dessus du corps, et la ponctuation est plus eparse que chez I'obtusus, les angles posterieui's du corselet sont aussi moins saillants. Du continent Indien." 1457. Hydrovatus subrotundatus, Motsch., Et. Ent. 1859, p. 41. India. " L'espece la plus courte et la plus arrondie que je possfede de I'Inde, aryant la taille et les couleurs du Hydr. obtusus, mais tres luisante et g^neralement plus large et plus convexe. La tete parait un peu moins obtuse en avant, le chaperon plus margin^ sur le bord ; le corselet plus fortement retreci en ayant, les Elytres plus convexes, k ponctuation moins distincte et avec l'extremite encore moins saillante." 1458. Hygrotus impressifrons, Motsch., Bull. Mosc. 1859, III, p. 165. California. " (Hydroporus) elongato-ovatus, convexiusculus, utrinque jequaliter attenuatiis, punctatissimus, nitidus, piceus, capite macula media, thoracis margine latissime, elytrorum limbo, maculis ad basin, ejjipleuris, ore, antennis pedibusque testaceis ; corpore subtus nigro, grosso punctate ; capite antice bifoveolato, epistoma marginatum, thoi-ace transverso, basi medio producto, lateribus subarcuatis, angulis anticis prominulis, posticis obtusis, subrotundatis ; elytris thoracis latitudine, in medio regulariter subdilatatis, striis minus distinctis. Long. \ 1., lat. % 1." In the remarks which follow this diagnosis, this species is said by its form to approach " Hygrotus lineatus" and even " Hygrotus confluens." It is from San Francisco. I do not think this description is intended to apply to any species I have seen. — D. S. 816 On Aquatic Carnivorous Coleoptera or Di/tiscidce. 1459. Hyphydi-us aiistio-caledonicus, Penouil, Aim. Soc. Luui. Lyon XI, 1864. p. 74. New Caledonia. " Ovatus, crassus, supra conve-xiusculus, rubro-brunneus, capita Ireve, ferrugineo-i-ufo. Prothorace bmnneo, lateribus rufis, supra i-ugi.iloso. Elj-tris coriaeei.s, liaeis punctatis, plus miuusve distinctis subtiliter impressis. Subtus corpore pedibusque rufis. Long O", 0035 ; lai-g. 0", 002." I am doubtful whether this \\-ill prove to really be a Hyphydrus.— D. S. 1460. Hypliydnis caffer, Boh., Ins. Cafi". I, p. 247. Caffraria. "Ovatus, bre^-is, crassus, supra vix couvexus, dense, evidenter punctulatus, rufo-testaceus, nitidus; prothorace nigro, antiee utrinque rufo-testaceo-marginato ; elytris doi-so sub-planis, singulo fasciis duabus, transversis, undulatis, rufo-testaceis, una mox pone basin communi, altera mox infra medium, iutus abbreviata. Long. 6, lat. 4 m.m." Eastern Caffraria. The description seems to indicate a large species unknown to me. — D. S. 1461. Hyphydrus cayennensis. Cast, Et. Ent., p. 107. South America. "Long. 1^ ligne, larg. 1 ligne. Fortement ponctue; tete et corselet d'un bruu rouge; elytres tres noii-es, un peu luisantes ; dessous du coi-jjs d'un brun nou- ; pattes un peu claires ; antennes jaunatres." This is no doubt a Pachydrus. Aube has also given a description (Spec. p. 456) of what he considers to be Castlenau's species, from a specimen (or specimens) in Buquet's collection, but his description of the sculpture does not accord with Castlenau's. — D. S. 1462. Hyphydnis circumflexus, King, Monatsber. Berl. Acad. 1853, p. 250. " H. inifo-testaceus, supra convexiusculus, confertim piinctatus, thorace antiee posticequc nigi-o, elytris basi, sutura, vittis duabus, maculisque nigris. Long. liii. 2." " Dieser noch unbeschriebene Hyphydrus ist, wenn gleich anderen africanischen arten, zunachst dem H. scriptus, Aube, sehr nahe verwandt, von letzerem schon dadurch leicht zu unterscheiden dass die gauze obere seite mit kleiueu eingedruckten Punkten gleichmassig bedeckt ist, irgend grossere punktere eingestreut siud und von den abgekiii'zten Punktstreifen in der mitte der Deckschilde sich kaum eine andeutung findet. Die grundfarbe ist ubrigen dieselbe wie bei dem H. scriptus und den ahnlichen arten. namlich ziemlich lebhaft braungelb. Kopf, beine, und iintere seite sind ebenfalls wie bei dem H. scriptus. Das halsscliild ist vor seinem vorderem und liinteren rande iu nur geriuger ausdehnung schwarz. An den Deckschildchen sind die basis mit ausnahme der schultern, von dort bis zur spitze hin die uaht zu beiden seiten iu Gestalt vollstandiger Binden, hierauf eine mit der naht brnde gleich laufende, Uir anfanglich sehr geniiherte, aber weder Basis noch Spitze erreichende zweite Binde, in der mitte zwischen dieser und dem aussenrande eine vorn nach den Schultern umgebogene, nach hinten noch mehr abgekui-zte dritte Binde, ein fast dreieckiger Fleck unter dieser und noch ausserdem zwei langliche Flecke dicht am Rande schwarz. In eiuem einzelnem Exemplare von Tette." I should suppose this may be a species allied to Hyphydrus madagascariensis. — D. S. 1463. Hj-]ihydrus globosus, Aube, Spec. p. 457. Antilles. " Ovatus, brevis, crassus, convexus, spai-sim punctis oblongis impressis, supra nigro-piceus, infra riifo- ferrugineus ; thoracis lateribus obliquis ; elj'tris apice rotundatis. Long. 4 m.m., larg. 2j m.m. " " Les males et les femelles sont semblables. " \A description follows 1. c. the above diagnosis.^ This speii<>s no doubt should be referred to the genus Pachydnis, and is probably near P. Ijrevis, which is from tin; sauu' locality ; Aube's species however would appear to be rather larger and to have some of the punctures on the elytra and thorax elongate, not round. The French author describes the species from a single individual in Guerin's collection from Porto Eico. — D. S. On Aquatic Carnivorous Coleoptera or Dytiscidoe. 817 1464. Hypliydrus liyperboreus, Gyll., Ins. Suec. IV, p. 388. Lapland. " Oblongo-ovatus, tenue pubescens, thorace depres.so feiTugineo, lateribus rectis obliquis, dorso maculis duabiLS nigi'is, liberis, elytris nigris, ferrugineo marginatis et lineatis. " H. depresso plus diijilo nimor, forma et pictura thoracis abunde distinctus." \A lotig description, 1. c, Jollows the above.] From the unique female I have examined, I tliink this \vill prove to be a local variety of Dytiscua assimilis, Payk. (No. 471 ). — D. S. 14G5. Hypliydrus illigeri, Perroud, Ann. Soc. Linn. Lyon. XI, 1864, p. 75. New Caledonia. " Ovatus, crassus, sujDra convexiusculus, dense iiTegulariterque punctatus, rufo-testaceus. Prothorace ad margineni auterioi-em vitta transversali nigra (interdum deficiente) et ad marginem posteriorem macula gemina nigra, notato ; lateribus obliquis tenue reflexis. Elytris medio longitudinaliter subcostatis singulatim \'itta longitudinali laciniato-sinuata valde irregulari, nigro-picea ornatis ; sutura etiam nigi'O- picea. Long. O", 005 ; larg. 0», 003. " Pris a Kanala. " Cette espece a de tres grands rapports avec I'Hyph. variegatiis, mais elle est plus ovale moins epaisse sa ponctuation quoique tres serrce est moins forte, elle manque de strie suturale, et ses taches sont autrement faites. Les exemplaires que j'ai regu de M. Montrouzier sont des males et par consequents briUants." I think this may perhaps prove to be Hyphydrus australis, Clk. (No. 358) — D. S. 1466. Hyphydrus johnsonii, Clk., Joum. Ent. I, 1862, p. 405. Australia. " Ovatus, brevis, punctatus, testaceus ; thorace ad medium nigro-fusco, ad latera testaceo ; elytris quatuor aut quinque lineis infequalibixs fuscis a medio ad apicem, pedibus antennisque flavis. Long, coi-p. 2 lin., lat. 1 Un." " Broadly ovate, somewhat depressed, thickly punctate, of a testaceous or flavo-testaceous coloui' : head with two oblique medial fovete, in colour testaceous : thorax broad, transverse, in colour dark fuscous, the margins being testaceous : elytra broad, thickly and finely punctate ; near the shoulders are traces of pubescence ; in colour pale flavous, with four or five longitudinal lines of fuscous extending from the middle to the apex ; these lines are frequently interrupted and irregularly suflused : abdomen and under side thickly punctate, rufo-fuscous : legs and antennae flavous." Victoria. This is, I believe, a species of Chostonectes, allied to Nc. 425. — D. S. 1467. Hyphych-us lugubris, de Bon-e. Ann. Sac. belg., XIV, p. 10. Sinai. " Ovatus, brevis, crassus, convexiusculus, thorace fortiter, elytris leviter punctatis. Fern., nigro-piceus, obsolete sanguineo-maculatus." Long. 4-|, lat. 3 m.m. " Ovale, court, ayantla meme epaisseur et la meme convexite assez mediocre que H. ovatus. Entifere- ment d'un noir trfes fonce et un pevi luisant, avec une vague tache humerale rouge sombre sur chaque elytre ; quelques teintes de la meme nuance se montrent an sommet de I'e'lytre en dehors. Devant de la tete trfes-aplati, plus long et moLns large que chez notre H. ovatus, reborde circulairement en avant d'lm ceil a I'autre, finement, mais irreguliferement ponctue, avec une petite fossette de chaque cot^. Antennes et palpes un peu rougeatres. Corselet environ 2^ fois aussi large que long, 6chancre en avant, reborde sur les cotes ; sa base s'avancant au milieu entre les ^lytres en formant iin angle obtus. Les angles anterieurs assez saillants, les postcrieurs droit. II est fortment et nigueusement ponctue sur toute sa surface : la ponctviation est iin peu moins gi-ossifere sur le disque, des deux cotes quelques strioles longitu- dinales parallfeles assez apparentes au milieu de la base. Elytres a ponctuation faible et inegale (Fem.) ; une ligne longitudinale formee de points 2ilus forts, sur le disque, n'atteignant pas tout-a-fait la base et cessant poste'rieurement aux | de chaque elytre. Une autre ligne semblable, mais beaucoup moins marquee, longeant la suture de chaque cote. Dessous du corps et pattes aussi d'un noir de poix faiblemeni 818 0?) Aquatic Camivornus Coleoptera or DytiscidcB. brillant. Poitrine et abdomen a ponctuation fine et inegale. Les tibias post^rieurs terminus par un longue epine rougeatre, ainsi que rextremite des poils que fonnent la frange des tarses natatoiies de la meme paire." This insect, described from an unique female in the collection of Crotch at Cambridge, api^ears to be unknown to me. — D. S. 1468. Hyphydrus maculatus, Bab., Tr. Ent. Soc. Lond., IIT, p. 12. South America. " Ovatus, brevis, gibbus, fuscus, capite, thoracis lateribus elytrorumque maculis testaceis, subtus fuscus • antennis testaceis, pedibus fuscis. L. 2, lat. \\ Hn." " Short, ovate, gibbous, the whole upper siirface coarsely punctate. Head testaceous ; in one specimen fuscous. Antenniv testaceous. Thorax transvei-se, similar to H. ovatus, fuscous. Elytra ovate, much dilated near the middle, the apex rounded, fuscous, except a bilobed spot at the base ; the hiimeral angle, the anterior half of the lateral mai-gin, a longitudinal abbreviated Une near the centre of the suture, one on the middle of the disk connected ^vdth a triangular transverse spot on the margin, and two small triangular spots connected with this last, and with each other within the apex, which are testaceous. Body beneath fuscous, coarsely punctured, very gibbous. Legs fuscous." " This pretty little insect was obtained at St. Jago." The specimen of this species in the collection of the British Museum, appears to be a species unknown to me, belonging to the genus Hyphydnis ; as, however, the other species of Hyphydrus are confined to the Old World, I suspect there is some error in the locality given by Babington.^D. S. 1469. Hji^dius rufus, Clk., Trans. Ent. Soc. Lond. 1863, p. 423. China. " Ovatus, brevis, crassus, corpore supra convexiusculo, va]d6 punctato, rufo, nigro-lineato ; capite Bnticfe marginato, punctato, thorace antic6 emarginato, ad latera obliquato (subrotundato) tenue margi- nato, ad basin sinuato, et ad medium lat6 angulato, punctato, rufo ad basin plus minus fusco-adumbrato ; elytris latis, brevibus, dense et fortiter punctatis, sutura et quatuor lineis nigiis, parallelis, aUquando obscuris, interduni post mediiun breviter interruptis ; corpore subtus valde punctato, rufo ; antennis pedibusque ruiis. Long. corp. 2 lin. ; lat. li lin." The type of this species in the collection of the British Museum is apparently a species unknown to me, allied to Hydroponis solieri (No. 371) of the genus Hyphoporus. — D. S. 1470. Ilybius badeni, Wehncke, Berl. Zeit. XV, p. 164. Hamburg. " Oblongo-ovatus, convexus, supra piceo-seneus, margine brunneo. Long. 5 lin." " Zur gi-uppe~mit bogenfbmiigen vorden-ande der hinterhiifteii, ziemlich breiten, fast dreieckigen seiten- flugeln des metastemums gehbrend und dem L subaeneus am ahulichsten, doch durch eine gewolbtere form und die farbc unterschieden. Die oberseite ist dunkel erzfarben mit deutUchen fensterflecken, der seitem-and des halsschUdes der flUgeldecken sowie die ganze unterseite mit den beinen rothbraun." I doubt whether this be distinct from I. subseneus (No. 783). — D. S. 1471. Ilybius kiesenwetteri, Wehncke, Bei'l. Ent. Zeit. XVI, p. 136. Germany. " Oblongo-ovalis, convexiusculus, ater, elytris guttulis duabus pellucidis. Long. 9 m.m." " Dem I. guttiger sehr ahulich und audi von dei-selben faibe, doch ist die gestalt etwas kiirzer und gewblbter." " An flf-n hinterfiissen der mannchen ist die aussere Klaue am ende hakig gebogen wie bei 1. ater, wiihrend dieselbe bei I. guttiger (wie bei obscurus) doppelt so breit als die innere mit abregundeter Spitze geformt ist." "Bei Harbxirg sehrselten." On Aquatic Carnivorous Coleoptera or Di/tiscidce. 819 1472. Iljbius ovatus, Hoch., Bull. Mosc. XLIV, p. 237. Eiis.sia. " Perfecte ovalis, leviter convexus, niger, supra vix seneo-micans, elytris apicem versus oblique sub- truncatis, lineis duabus rufo-fernigiueis fenestratLs. Long. 5 1." "Am nacbsten stelit diese art dem I. subasneus, Er., ist aber scliwarz, mit viel schwacheren griinlichen schimmer als jener. Seine umriss unterecheidet sie von alien mir bislier bekannten arten ; diese istein vollkommenes ovale, dessen breiteste stelle etwas hinter der mitte der Fliigeldecken fallt." 1473. Ilybius suffusus, Crotch, Tr. Am. Ent. Soc. IV, p. 411. North America. " Closely resembling the two preceding (i.e., C. angularis, Lee, I. pleuriticus, Lee), but more allied to I. pleuriticus by the less coarsely punctate tibise ; colour brassy, sculpture very fine, the whole margin of the elytra broadly and irregularly ferruginous, hiding the usual pale spots. L. "44 inch. Indian Territory." A female individual recently sent me by Dr. Horn indicates this as a very distinct species, whose position is, probably but not certainly, near D. fuliginosus (No. 792), and I. meridionalis. — D. S. 1474. Laccophilus adspersus. Boh., Ins. Caff. I, p. 246. Caffraria. " Oblongo-ovalis, convexiusculus, postice angustior, apice oblique rotundatus, testaceus, nitidus ; prothorace immaculato, basi breviter acute producto ; elytris subtiliter, crebre nigro-reticulatis, lateribus anguste pallidis. Long. 4, lat. 2\ m.m." Caffraria interior. [This diagnosis is followed, 1. c, by a long descripiioji.^ I can form no opinion as to the species, except that it is unknown to me. — D. S. 1475. LacoophUus baeri, Regt., Ann. Soc. Fr. 1877, p. Ixxviii. Manilla. " Ovalis, postice vix attenuatus ; capite testaceo, lineis duabus transversis et incurvatis giiseo-notato ; prothorace testaceo, antice nigro-infuscato, postice linea transversa et leviter incurvata nigro-uotato ; elytris fusco-nigiis, margine, lata ad basin transversa vitta, latissime apice magnam maculam inclaudente et ssepe suturali linea flavo-ornatis ; subtus fusco-niger, pedibus testaceis, posticis ad tarsum infuscatis. Long. 3J m.m." This species and L. transversalis are, it would appear, remarkable on account of the dark marks on the head.— D. S. 1476. Laccophilus cayennensis, Aub6, Spec. p. 434. Cayenne, Guadeloupe. " Ovatus, apice rotundatus, deprussiusculus, rufo-testaceus ; thorace postice in medio breviter acute producto ; elytris creberrime nigro-irroratis, vitta irregular! transversa ad basin, maculis irregularibus ad latera et apicem lineolisque brevibus in disco, pallido-ornatis. Long. 3^, larg. 2J m.m." \A descriptimi, 1. c, follows this diagnosis.^ 1477. Laccophilus decoratus. Boh., Eug. Res., p. 20. Manilla. " Oblongo-ovalis, postice attenuatus, leviter convexus, subtus ferruginous, nitidus ; antennis capite palpis, pedibusque flavo-testaceis ; prothorace dilute flavescente, antice posticeque medio leviter infuscato, elytris piceis, luteo-iiToratis, fascia lata basaU, altei'a insequali infra medium introrsum abbreviata apiceque dilute flavescentibus. Long. 3|, lat. If m.m." " Caput parum convexum, sub-lave, flavo-testaceum, nitidum. Palpi et antenme flavo-testacea. Oculi convex! glauci. Prothorax longitudine triplo latior, apice medio subtruncatus, utrinque leviter sinuatus, ba.si utrinque suboblique truncatus, medio vix triaugulariter productus, angulis anticis autrorsum modice prominulis, sub-acuminatis, posticis fere rectis ; supeme leviter convexus, vix punctatus, dilute flavescens, basi apiceque linea transvei-sa, utrinque valde abbreviata, dilute fusca ornatus. Scutellum nullum. TRAN3. BOY, DDB. SOC, N.3., VOL. II. 5 N 820 On Aquatic Carnivorous Coleoptera or Dytiscida. Elytra antice subtruncata, prothorace jianim latiora, quam lata duplo et dimidio longiora, ad mediiim liiiid ampliata, dein apitem vei-sus atteuuata, apice subrotundata, siiperne leviter convexa, vix punctata, picea, nitida, luteo-irrorata, basi fascia lata transversa fere ad suturam continiiata, postice medio triangu- lariter nonnihil ain]iU;ita, altera ]ione medium, iniequali, extrorsum latiore apiceque, dilute flavescentibus. Corjjiis subtus ferrugineum, nitiduui, obsolete coriaceum. Pedes flavo-testacei, nitidi, vix punctati." 1478. Laccophilus flavescens, Motsch., Etud. ent., 1859, p. 45. Ceylon. " De la forme allongee et de la taille dti Lace, basalis mais d'une couleur testac^e roussatre, uniforme, a rexce2)tion des yeiix qui sont noirs ; les 61ytres sent tres finement pointillees, avec deux stries peu visibles et formees de points tres petits, I'extremite est ari-ondie. La taille est un peu plus petite q>ie celle du notre L. minutus, mais moitie plus etroite." 1479. Laccopbilus hydaticoides, Regt., Ann. Soc. Fr., 1877, p. Ixsix. Manilla. " Ovalis, vix elongatus, minime postice attenuatus, sat convexus ; capita flavo ; prothorace flavo latissime antice et postice nigro-limbato ; eh'ti'is uigi'is, angusto margiiie, vitta transversa irregulari ad basin, duabus maculis latis in disco, alteraque lata ad apicem flavis ornatis ; subtus nigi-c-feiTugineus, pedibus testacies, posticis infuscatis. Long. 3 m.ui." \^At p. 359, op. cit., this diagnosis is supplemented by a description.'\ 1 480. Laccophilus Hneatus, Aube, Spec, p. 426. Mauritius. " Ovalis, apice paulo oblique rotundatus, depressiusculus, testaceus ; capite in vertice infuscato ; thorace antice et postice nigi-o-maculato, in medio bre\-issime acute producto ; elytris nigris, vitta transversa ad basin, lineolis pluriniis longitudinalibus maculaque irregulari paulo ultra medium ad latera et altera ad apicem, rufo-luteo-ornatis. Long. 4, larg. 2^ m.m." [A description, 1. c, follows the above diaynosisJ\ 1481. Laccophilus mexicanus, Aube, Spec, p. 420. Mexico. " Ovalis, apice vix oblique rotundatus, dopressiusculis, supra testaceus, infra nigro-piceus ; thoi-ace postice in medio bre\'iter acute producto ; elytris pellucidis, creberrime brimneo-iiToratis lateribus irregulariter testaceis. Long. 5 m.m., larg. 2f m.m." [This diagnosis is followed, 1. c, by a descripiion.^ The species is probably the same as Laccophilus atiisternalis (No. 104). — D. S. 1482. Laccophilus orientalis, Aube, Spec. p. 431. Java. " Oblongo-ovaUs, postice paulo angustior, apice oblique rotundatus, depressiusculus, supra testaceus, infra obscurior ; thorace immaculato, postice in medio breviter acute producto; elytris pallido-testaceis, vitta lata transversa fere in medio maculaque commiini ad apicem brunneis, crebre testaceo-irroratis ornatis. Long. 3^ m.m., larg. 2-1 m.m." [This diagnosis is followed, 1. c, by a description^] The species is perhaps allied to L. di.spersus, (No. 161). — D. S. 1483. Laccophilus ornatus, Aube, Spec. p. 432. Cayenne. " Oblongo-ovalis, apice paulo obliqvie rotundatus, depressiusculus, pallido-testaceus ; thorace postice in medio breviter acute producto ; elytris creberrime nigi-o-iiToratis, vitta iiTegulari transversa ad basin, maculis irregularibus ad latera et apicem lineolisquebrevibus in disco, pallido-ornatis. Long. 4, lat. 24 m.m.' [A description follows, 1. c, the above diagnosis. The species is perhaps near L. fumatus (No. 118). — D. S. On Aquatic Carnivorous Coleoptera or Dyliscidce. 821 1484. Laccophilus poecilus, Klug, Symb. phys. IV, t. 33, f. 8. Egypt. " Testaceus, elytris fusco-ii-roratis, fasciis duabus macularibus abbreviatis pallidis. Long. lin. 2. Habitat in Egypto." " L. ininuto cui affinis minor. Corpus subtus testaceum, immaculatuin. Caput et thorax rufo-testacea, imuiaculata nitida, antenuse testacese. Pedes testacei posticorum tibiis tarsorumque articulis apice obscurioribus. Eljrtra testacea, dbrso fusco-irrorata, maculis latei'alibus sparsis faciisque duabus maculari- bus transversis, prima uti-inque abbreviata baseos ab angulo liumerali versus suturam oblique descendente, altera paulo intra medium subtriangulari ad sutvu-am augustissima et fere obsoleta, pallidis." 1485. Laccophilus proteus, Regt., Ann. Soo. Fr. 1877, p. Ixxix. Manilla. " Elongato-ovalis, postice attenuatus. Capita testaoeo ; prothorace testaceo, postice linea transversali nigra ornato ; elytris nigro-fuscis, ad marginem testaceis, permultis lineolis undulatis, ad basin et apicem plus minusve confluentibus, testaceis ornatLs ; subtus fusco-niger, pedibus testaceis, posticis infuscatis. Long. 2| a 3^ m.m." \^At p. 3.58, op. cit., this diagnosis is stqjplemented by a description.^ 1486. Laccophilus piimilio, Lee, Proc. Am. Phil. See, 1878, p. 596. North America. " Ovate, pointed behind, not convex, unpunctured, rufo-testaceous, meso and metasternum darker ; elytra piceous, slightly iridescent, regularly narrowed behind, and not obliquely truncate at tip ; abdomen with- out the distant fine oblique lines seen in the other species. Length 1*9 m.m. ; '075 inch." " Enterprise, Florida ; one specimen. Very careful examination shows in certain lights traces of two or three lines on the second ventral segment towards the sides, but these are the only evidences of the characteristic ventral sculpture of the other sjjecies." 1487. Laccophilus quadrisignatus (Lap.), Aub^, Spec. p. 436. Cayenne. " Ovalis, apice rotundatus, depressiusculus, rufo-testaceus ; thorace postice in medio leviter iufuscato et breviter acute producto ; elytris brunneis, vitta irregulari transvei-sa ad basin alteraque ultra medium, macula minima ad marginem, altera in apice luteo-ornatis. Long. 3|, lat. 2J m.m." \_Auhe, 1. c, supplements the above diagnosis with a description.'] 1488. Laccophilus rivulosus (Klug), Aube, Spec. p. 425. Madagascar. " Ovalis, apice vix oblique rotundatus, depressiusculus, testaceus ; cajiite in vertice nigro ; thorace antice et postice nigro-maculato, in medio breviter acute producto ; elytris nigris, maculis irregularibus ad marginem lineolisque plurimis in disco testaceo-ornatis. Long. 5, lat. 3 m.m." {This diagnosis, 1. c, is followed by a descriptioyi.] This species is probably allied to L. lateralis (No. 148). — D. S. 1489. Laccophilus stroehmi, Th., Op. Ent. VI, p. 535. Helsingfors. " Ovalis, sat convexus, pallide testaceus, antennis palpisque apice nigris ; coleopteris medio dilatatis, subtilissime subrugoso-punctatis, fuscis, basi et lateribus dilutioribus." " L. minuto fere major, antennarum palporumque colore, elytris magis convexis, punctura evidentiore, fuscLs maculis pallidis nullis determinatis bene distinctus. Caput pallide testaceum, clypeo ante apicem linea subcurvata impi'essa ; palpis utrisque apice nigris. Anteunse pallide testacese, articulis 5-6 ultimis apice sensim magis nigris, quarto tertio breviore. Prothorax basi coleopteris fere angustior, latitudine sua triplo brevior, apice truncatus, angulis auticis sat magnis productis ; lateribus oblique antrorsum angustatis ; basi medio late subproductus, testaceus, Isevis. Elytra prothorace saltem quath-uplo longiora, lateribus paullo ante medium subdilatata, sat convexa, fusca, basi et limbo laterali pallicUore; punctis, 6 N 3 822 On Aquatic Carnivorous Coleoptera or DytiscidcB. praesertim postice, subtilissime crelire impressis, seriebus ordinaiiis subindicatis. Corpus subtus pedesque pallide testaceaj tarsis anterioribus maris leviter dilatatis." I think this may possibly be a variety of Dytiscus interruptus (No. 128). — D. S. 1490. Laccophilus transversalis, Regt., Ann. Soc. Fr. 1877, p. Ixxix. Manilla. " Ovalis, elongatulus, vix postice attenuatus, capite et prothorace ut in prsecedente (L. baeri) ; elytris nigris vel fusco-nigrLs, epipleuris, vitta angusta transversa post basin, altera irregular! paulo ante apicem atque apice fiavo ornatis ; subtus nigro-feiTugineus, pedibus testaceis, posticis ad tarsum iufuscatis. Long. Z\ a 3J m.m." [J« ;;. 357, op. cit., the above diagnosis is supplemented with a description.'] 1491. Laccophilus transversus, Motsch., Etud. Ent. 1859, p. 45. Biirmah. " Taille et forme du precedent (L. undulifer) mais au lieu des ondulations foncees sur les flytres il y'a des grandes taches transversales poLntillees de teinte testacee ; la base est obscure, puis on voit une bande testacee, interrompue sur la suture, enfin I'extremite meme et tout le bord des 61ytres est de teinte claire, ainsi que le corselet, la ttite et les pattes ; le dessous du corps un peu obscure." 1492. Laccophilus umbrinus, Motsch., Etud. Ent. 1855, p. 83. Egypt. " Presque deux fois plus grand que le L. interruptus, et de forme plus ovale et plus deprimee. Couleur d'un brun un peu verdatre avec les bords du coi'selet et ceux des elytres plus clairs." 1493. Laccophilus uniformis, Motsch., Etud. Ent. 1859, p. 46. India. " Tout-a-fait comme le precedent (L. flavescens) mais avec les elytres plus larges et fortement attenu^es posterieurement, presque comme chez notre minutus, ponctuation des elytres indistincte. Du continent Indian." 1494. Laccophilus venniculosus, Gerst., Beitr. Ins. Zanz. 1806, p. 25. East Africa. " Oblongo-ovatus ferrugineus, prothoracis margine basali plagaque disci transversa nigris, elytriafusco conspersis, margine laterali, (basi et ante medium maculatun dilatato) testaceo. Long. 4| m.m." " Dem L. rivnlosus, Klug, nicht unahnlich, aber etwas kleiner und von abweichender Zeichung des prothorax." Mombas. 1495. Laccophilus y\'ict£e, Le GuU., Rev. Zool. 1844, p. 220. Chili. " Tete et corselet jaunes, celui ci ayant le bord posterieur et un tache transverse au milieu du bord ant^rieur noirs. Elytres noires, tres finement chagi'inees avec une bande transversale maculaire pres de la base, ime autre bande fonnee de petites stries tres rapprochees pres de i'angle apical et le bord exterue jaune. Dessous noii", antennes et pattes jaunes. Long. 3^ lat. If m. m. Hab. le Chili." 1496. Necterosoma fla-sacolle, Macl., Ti-. N.S.W., p. 125. Australia (Gayndah). " Length IJ lines. This species diffei-s fi-om the last (N. vittipenne) in having the frontal depression more round and very shallow, in having the thorax entii-ely yellow, with a depression at the base equi- distant from the centre and the posterior angles, in which there are three or four small but distinct striolae, and in having the elytra without striolse on the scutellum region, .md of a yellow colour, with a serius of six vittse, and some lateral spots, brown, the second vitta from the suture being abbreviated towards the base and apex. The elytra also are quite acuminated at the apex, much more so than in N. vittipenne." Welincke, on the authority of an authenticated specimen, considers this to be Hydropoi-us wollastoni, 01k. (No. 441).— D. S. On Aquatic Carnivorous Coleoptera or DytiscidcB. 823 1497. Necterosoma vittipenne, Macl., Ti-. N.S.W., p. 125, Australia (Gayndah). " Length 2 lines. Ovate, broad, subconvex and of a yellow colour. Head with a shallow slightly elongated fovea on each side in front. Thorax broad, short, and bisinuate at the base, witli the basal lobe rounded, the posterior angles acute, the anterior angles advanced, the apical border brown, the basal border also bi'own and enlarged into two spots aliout midway between the centre and the posterior angles, and with a small striola at the base on the outer side of these brown spots, and a series of smaller sti-ioloe along the whole basal border. Elytra dark-brown, with five yellow vittse on each side of the sutm-e, extending from the base to the apex, with lai'ge spots of the same colour on the sides, and witli one or two oblique striolse on tlie scutellar region, giving the appearance of a large scutellum." Wehncke on the authority of an authenticated specimen considers this to be the same as Hydi-oporus penicillatus, Clk. (No. 436).— D. S. 1498. Noterus imbricatus, Klug, Monats. Berl. Ac. 1853, p. 249. East Africa. " N. pallide testaceus, elytris bruneo-testaceis, transversim Tmdato-exasperatis. Mas, Fern. Long, lin. 2i." " Ganz ebenso gestaltet und fast ebenso gefarbt, wie der hier gewohnliche N. crassicornis. Die untere seite nebst den Beinen, so wie Kopf und halsschild sind einfarbig hell rbthlich gelb, Kopf und halsschild ganz glatt, die Augen schwarz. Die Deckschilde sind besonders bei dem Weibchen mit dicht an einander gereihten, in querlinien geordneten, beinahe wie Dachziegel aufliegenden erhohten punkten diu'chzogen, wie sich dies bei keiner andern hier bekannten art der gattung findet." "Miinchen and Weibchen von Tette." This is evidently to be placed in Synchortus, and is near if not identical with either Hydi'ocanthus asperatus, or H. rugoso-punctatus (Nos. 18 and 19). — D. S. 1499. Pachytes elegans, Montr., Ann. Sec. Fr. 1860, p. 245. New Caledonia. " Long 5, larg. 3 m.m. La tete est lisse, jaune fonc6, le chaperon reborde en avant. Les yeux grands, les antennes et les jjalpes jaunatres, le corselet transversal, finement pointille, est de la meme couleur. Les 61ytres ovales, legferement con vexes, arrondies au bout, couvertes de petits points enfonces sont noires avec la bordure, une tache en crochet a la base pr6s de la suture, une autre allongee vers I'extremite et une troisifeme entre elles, vers le milieu du limbe, jaunes. Une tache noire dans la bordure prSs de 1' angle humeral. Dessous du corps et pattes fauves, avec I'extremite rembrunie. Dans les mares — He d'Art, rare. N.B. Les couleurs disparaissent pour la plupart aprfes la mort." The description of the generic characters is, p. 244, as follows. " Caracterfes g^neraux des Hydroporides. Antennes a peine setac6es, presque aussi gpaisses a I'extrgniit^ qu' a la base ; dernier article des palpes a peu prfes de meme longueur que le pr^c&lent ; presternum aigu postdrieurement, ^cusson cach^ ; tarses ant^i'ieurs termines par un trfes petit article ; jambes posterieures ayant a I'extremite deux crochets inegaux ; corps ejjais. Difffere des Hyphydres d'llliger par le dernier article des palpes et des Hydi-opores par les crochets des jambes." So far as T can judge from the descriptions of the genus and species, this may be an insect of a genus unknown to me, but I think more probably it will prove to be a Hyphydrus. — D. S. 1500. "Rhantus (?) consimiHs," Motsch., Bull. Mosc. 1859. Ill, p. 168. California. " Elongato-ovatus, depi-essiusculus, subnitidus supra subtUissime rugulosus, nigro-piceus, ore, palpis, anteimis, thoracis elytrorumque margine dilutioribus ; cajute subtriangulare, antice oblique biimpresso ; thorace transverse, antice angustato, basi arcuato, lateribus marginatis, subreflexis, angulis anticis promi- nulis, posticis, acutis, subsinuatis ; scutello fere la?ve ; elytris elongato-ovatis, postice subdilatatis, serie una punctorum distincta, lateribus latissime reticulatis, subopacis, (Fem.) ; tronchanteribus obtusis. Long. 4i 1., lat. 2^ 1." San Francisco. b2i On Aquatic Carnivorous Colcoptera or Dytiscidoe. " Par sa foiiue allongee il resseinble un peu au R. di^asus, Esch., mais il est plus giand et presente une couleur plus foiic6e. La tete est assez large, avec deux impressions en avant et une ligne longitudinale peu marquee au mUieu. Le corselet est fortement ti-ausversal dilate en an-ifere avec les angles postei-ieurs et anterienrs aigus et saUlants ; vers la base il y a une impression transversale peu profonde et au milieu une ligne longitudinale qui n'atteiiit ni la base ni le bord anterieur. Les elytres ne sont presque pas plus larges que le coi-selet, un peu dilatees postOrieui-ement et peu acuminees a I'extremite, siu'cLacuue on voit un peu au dela du milieu une stiie formee par de petites foveoles eparses, dans le fond desquelles il y a 3 ou 4 points imprimcs ; le bord lateral est anterieurement sur une largeur d'un tiers de toute I'elytre plus fortement reticule et plus opaque que la partie vers la suture, qui parait aussi obscure que la couleur gfoerale ; vu de cot^ on' appei-coit sur les elytres des ondulations roussatres et noiratres, propres aux espfeces du genre RLautus. Le dessous du corps et les 6pipleures sont plus noir-atres que le dessus." This Ls possibly allied to Colymbetes sinuatus, Lee. (No. 94-1). — D. S. 1501. Rhantus flavogriseus, Crotch, Tr. Am. Ent. Soc. IV, p. 409. North America. " Allied to C. binotatus but more elongate, nan-ower, the discal spots on the thorax transversely quadrate, beneath black, prosternal carina pale, femora black. Mas, anterior claws elongate sub-equal, sinuate, intennediate internal claw inidimentary." 1502. Rantus luteicollis, GebL, Bull. Mosc. 1848, III, p. 72. Siberia. " Elongato-obovatus, totus flavescens, elytris svibtiliter nigro-irroratis, trilineatis, oapite lineola trans- versa siuuata punctoque verticis nigris. Long. 5 lin., lat. 3 liu.'' " Nahert sich dui'ch seine fliiohere, breite gestalt dem R. adspersus, F., ist aber etwas langlicher und hat ein verhaltnismassig breiteres, flacheres halsschild." Loktemsk. 1503. Rhantus nigriventris, Motsch., Schrenck, reise, p. 101, pi. 7, f. 6. Kamtschatka. " Ovatus, subconvexus, nitidus, testaceus, macula transversa frontali capite postice, oculis, macula in medio thoracis corporeque subtus nigris ; elytris nigi-o-kroi-atis, punctorum triplici serie subconfluentibus. Long. 4 1., lat. 2^ 1." " Tres voisin de notre Rh. conspersus, mais de forme plus large et plus convexe, ayant le dessous du corps, a I'exception des cotes du corselet, noir." 1504. Rhantus nigro-punctatus, Motsch., BuU. Ac. Pet. I, 1860, p. 293. Songoria. " Ovatus, subconvexus, subnitidus, fulvo-testaceus, in fronte macuUs duabus, capitis basi, elytrorum puuctis triplici serie margineque segmentorum abdominis interdum nigris ; elytris fusco-irroratis. Long. 3^ 1., lat. 2^ 1." " II ressemble beaucoup a notre Rh. adspersus, F., mais sa forme parait unpeu plus allongle, sa couleur toujours plus claire, son corselet sans tache noire au milieu de la V)ase, les trois rangees de points noii-s sur les elytres tres distinctes, tandLs que les teintes noires sur les segments du dessous du corps souvent presqu' entierement effacfiea." 1505. Scutopterus imbricatus, Woll., Tr. Ent. Soc. 1871, p. 220. Madeira. " Oblongo-ovatus, elongatus, subopacus, nigro-piceus, capitis parte antica macidisque duabus frontalibus et prothoraois lateribus piceo-ferrugineis ; capite prothoraceque rugose coriaceis, hoc autice angustato ; elytris elongato-ovatis basi truncatis, paululum nitidioribus, grosse subimbricato rugulosis et obsolete subtestaceo commixtis, singulis longitudinaliter triseriatim notatis ; antennis i)alpisque rufo-ferrugineis, pedibus i-ufo-piceis. Long. corp. 10 lin." On Aquatic Carnivorous Coleoptera or Dytiscidce. 825 " Species S. lanioiii affinis, seel corpora magis ovato (antice, et in elytris et in pi-othorace, angustiore), elytris obscurioribus, minus nitidis, et rugose imbricato-asperatis, pedibus (ciliisque in posterioribus) picescentioribiis. A S. coriaceo (Europfeo et Canariensi) differt coiijore minus obtuse oblongo {i.e., antice angustiore) omnino minus nigro, capite distinctius maculato et protliorace ad latera ferrugineo, necnon. etiam in elytris obscure pallido-irroratis, prothorace paulo minus transverso, postice minus sinuate (angulis basalibus I'ectioribus) scutello sensim minus triangulari, et elytrorum impressionibus (in seriebus tribus dispositis) magis rotvmdatis, punctiformibus." \A further description and comparison follows, I.e., the preceding. "[ From which it appears that the single female — all that is known of the species — " appears to be in many respects exactly intermediate between S. coi-iaceus (of Southern Europe and the Canaries), and the Madeiran S. lanio." — D. S. ^ 1506. Suphis punoticollis, Crotch, Tr. Am. Ent. Soc, 187.3, p. 397. North America. " Ovate, convex, testaceous, shining ; elytra piceous ; thorax and elytra coarsely and tolerably closely pimctate. L. -12 inch." According to a specimen recently communicated to me by Dr. Leconte, this is a very distinct species of Canthydrus, jierhaps best placed near Suphis lineatus, Horn (No. 48) ; the thorax has an infuscate area on the front of the middle, and the elytra are marked with a transverse in-egular yellow mark, starting from the side in front of the middle but not reaching the sutiu-e ; the punctuation of the prothorax is only conspicuous on the basal portion, but that of the elytra is veiy conspicuous. — D. S. 1507. Suphis semipunctatus, Lee, Proc. Am. Phil. Soc, 1878, p. 595. North America. " Elongate-oval, not pointed behind, moderately convex, yellow-brown, shining, smooth ; elytra darker, covered from the middle to the tip with scattered coarse punctures ; of which one series extends to the base half way between the margin and suture. Prosternum not punctured, less dilated behind than in the other species, but with two short posterior strise ; metasternum with a deep impressed median line, smooth, with only a few scattered punctures behind. Length 2-6 m.m. ; -10 inch." " Monroe, Michigan ; one specimen ; veiy different from the other species by the regularly oval form, scarcely narrower behind than before, by the peculiar punctuation of the elytra and by the impunctured sterna. The last joint of the maxillary palpi is nearly acute at tip, and does not appear emarginate from any point of view." This is probably a species of Canthydrus, not of Supliis. — D. S. 1508. Thermonectes intermedins. Crotch, (basilaris var.), Tr. Am. Ent. Soc. IV, p. 402. California. " Thorax without the medial line (of Dytiscus basilaris), elytra with a humeral ■vatta and a mere trace of the basal fascia ; undersurface rufo-testaceous." This is cited as a distinct species in the check list of North American Coleoptera ; but according to a specimen recently communicated to me by Dr. Horn, it is considered by me a variety of Dytiscus basilaris (No. 1071).— D. S. 1509. Trochalus rugulosus, Eedt., Hug. Kasch. IV, 2, p. 502. India. " Ovatus, olivaceus, subtus niger, thoracis elytronimque margine laterali, ore, antennis, palpis pedibus- que anterioribus fiavo-femigineis ; elytris subtilissime rugulosis. Long. 10|"'. Caschmir." " Den kleinsten Individuen des Troch. africanus, kaum an grtisse gleichkommend iind nebst bei nach hinten bedeutend erweitert, so dass sein umriss der voUkommenen Eiform beiaahe entspricht. Die. 826 On Aquatic Carnivorous Coleoptera or DytiscidcB. vinterseite ist schwarz, die vier vordei-sten Beine, eine Makel an den Seiten der Bruat, und eine kleinere beiderseits an jedem der %-ier letzten Bauchringe, rostgelb." " Weibchen iinbekannt." This perhaps may prove to be near Dytiscus rugosus (No. 1167). — D. S. 1510. Trogus natalensis, Welmcke, Stett. Zeit., 1876, p. 358. S. Africa. " OvaUs, depressiwsculus, supra nigro-oUvaceus, subtus testaceiis, labro, tlioracis limbo, elytrointm margine, pedibxisque luteis, femoribiis posterioribus basi, tibiisque fuscescentibus. Long. 22 m.m. Fem. elytronim margine laterali subtUissime irregulariter striolato." " Von T. scutellaris, Germ., dem diese art am nachsten vei-wandt ist, durch eine vial kurzere imd breitere form unterschieden. Eiformig, hinter der mitte am breitesten, dunkel-olivengi-iin, die seiten des halsschildes nnd der flugeldecken gelb gesanmt unterseite mit den beinen gelb, an den hinter beinen die wiirzel der schenkel sowie die schienen braunlicli. Die iiiigeldecken der mannchen sind glatt, die der weibchen an den seiten gestrichelt. Port Natal." It is possible this may prove to be allied to Cybister reichei (No. 1148.) — D. S. 1511. Vatellus grandis, Biiq., Ann. Soc. Ent. Fr. 1840, p. 294. Cayenne. "Long. 7^ m.m., larg. 3f m.m. — Cette espfece, voisine du Vat. tarsatus, en differe par sa taUle, du double plus grande, par la forme du corselet, qui relativement, est plus caiTee, et parce qu' an lieu d'etre entierement ponctue, il n' a «;a et la que quelques gros points enfonces en dessus, et ime bande lisse, transversale au milieu. Elle en differe encore par la foi-me des elytres, qui sont proportionnellement plus allongees, plus planes, et couvertes de points enfonces bien distincts, tandis que dans le Vat. tarsatus ces points sout beaucoup plus i-approches, et disposes de maniere a faire paraitre les 61ytres comme sUlonnees transversalement : du reste elle est d'un uoir plus prononce que le Vat. tarsatus, et assez brillant." " Get insecte a ete trouve par M. Leprieur, en decembre 1837, dans les parties laterales du lit du haut-Oyapok, dans des flaques d'eaxi, et sous les detritus." It appears probable from the above description that this is a species unknown to me of Macrovatellus, perhaps near M. rudis (No. 84). — D. S. [ 827 ] IV. — Synthesis, or Classification. F I E S T SYNTHESIS (G E N E II A). I. 1.— Genus PELOBIUS. {Vide p. 259.) This aggregate is formed by three species ; their individuals are of moderate size (about 10 m.m. in length), the form is short and broad, very convex beneath, the surface very densely punctured, without pubescence. The head is exserted from, and little clasped by the angles of the thorax ; the eyes are convex, prominent, and not touched by the thoracic angles; the labrum is quite exposed in front of the clypeus, and perfectly continuous in plane with it ; the suture separating the clypeus, or epistoma, from the forehead, is angulated in the middle (and is very distinct in the Eui-opean, nearly obliterated in the Austrahan species) ; the buccal and gular sutures are fine but distinct in Dytiscus tardus, nearly obliterated in Pelobius niger ; the antenna is inserted in a small cavity situated at the upper part of a rather large, subtriangular glabrous space, and is 11-jointed; the basal joint is much larger than any of the others and more or less punctate, the other joints are without punctuation, but each bears on the ujsper surface quite at the extremity, a minute round cavity ; none of the joints has any pubescence, or elongate setae ; but by very minute examination it can be seen that there are, at any rate on the three or four basal joints, the rudiments of a few setae. The mentum is very short, its lateral lobes extremely short ; the palpi are rather short and stout ; the outer lobe of the maxilla is rather obscurely biarticulate. The prothorax has the sides of the upper surface distinctly, and the anterior margins both of the pronotum and prosternum densely ciliate ; the prosternum along the middle, assumes directly at the front margin a vertical direction, and shortly thereafter is turned backwards and continued so as to form a thick, prominent, prosternal process; this process is not broad but is elongate, and is nearly acuminate at the apex, it is margined at the sides, and the margins are continued forwards between the front legs, till they attain the anterior vertical portion of the prosternum; the prosternal sutures are indistinct as are also those of the side pieces; the form of the prothorax is such as to give it a great extension in the vertical direction ; thus the depth from the hind margin of the pronotum to the apex of the prosternal process ]ii 4 m.m., this measurement being distinctly greater than the width of the prosternum ; this considerable depth enables the front coxse to be conical and elongate; their cavities are closed behind by a large corneous process, connecting the inner faces of the two epimera. TRANS. EOT. DUB. SOC, N.S., VOL n. SO 828 On Aquatic Carnivorous Coleoptera or Dytiscidce. The mesosternum is rather short, and although placed at an evident angle with the plane of the metasternum, is very distinctly displayed between it and the prosternum. The episternum is very large in comparison \\ ith the epimeron, this latter being sub-linear, that is but little broader at its upper angle (or point of junc- tion with the angle of the metathoracic episternum), which is very broad and rounded and very indistinct, its inferior portion penetrates to the middle coxal cavity ; the lower portion of the metasternum is prominent, and forms a rather narrow moderately deep fork for the accommodation of the prosternal process. The metasternum is short, the middle portion of it is pi'oduced in front so as to form an inter-coxal process which is much depressed in front, for the reception of the prosternal process; the inter-coxal process, although elongate, does not attain the fork of the mesosternum, and the middle coxae (when the prosternum is taken off) are absolutely contiguous, and their cavities largely confluent; the posterior edge of the metasternum in the middle is connected with the internal laminae of the hind coxae by a transverse suture, and in front of this is marked by another transverse suture' which connects at the outer border of the pyxal process with the one just mentioned, so that a conspicuous supplementary piece exists at the front of the internal coxal laminae ; the episternum is large, and although broad at its anterior part, does not penetrate to the middle coxal cavity, its apex in fact is widely separated therefrom ; the posterior portion of the episternum is narrow, the upper edge of it is covered by the wing-case, and is smooth and shining so as to be greatly differentiated from the main part; the epimeron is entirely membranous. The hind coxae are of very peculiar shape; each is longest at the internal lamina, the outer portion being but short ; the greatest anterior extension of the coxa is near the mesial line of the body, in fact close to the outer border of the interior lamina, and external to this point the suture between coxa and metasternum proceeds outwards in very nearly a direct transverse line, which however slightly inclines backwards, till near its outer termination where it curves distinctly forwards to join the apex of the episternum : the internal laminae are closely and accurately conjoined with one another for their whole length by a perfectly straight, very distinct suture; outwardly they are abruptly defined and limited by a fine raised coxal border which extends their whole length, at the extremity each is marked by an elongate deep notch, in which the articular process of the trochanter moves, and which in fact forms the hmit of its motion towards the middle line of the body, so that the coxal cavities are conspicuously and rather widely separated. The visible ventral segments are six in number; the basal one is greatly inter- rupted in the middle for the accommodation of the pyxal processes, the suture be- tween the second and third is peculiar,* it is quite distinct at the side, and curves *Scliiodte (Danmarks Elentlierata, p. 414) Las proposed to separate Pelobius from all other Dytiscidse on account of this point of structure ; but this is quite impossible, for in the Hydroporides the character reappears to a greater or less extent {vide Dytiscus duodecimpustulatus. Fab., in the genus Deronectes). On Aquatic Carnivorous Coleoptera or Dytiscidce. 829 forward as it proceeds to the middle, and on the middle is very nearly obliterated, thus the second segment is extremely short in the middle, while the third is nearly twice as long in the middle as it is at the side, the three apical segments are short and freely flexible on one another. The wing-case has a conspicuous epipleura accurately adapted to the mesoster- num and metasternum ; at the side of the first ventral segment it becomes much narrower, and extends as far as the hind border of the fourth segment, where it has very nearly become attenuate to an edge : the extremity of the elytron is sinuate and its sutural angle rather acutely rectangular ; the inner face shows two peculiar structures ; first, near the outer edge about the middle is a raised process, a short irregular elevated plica or fold placed so as to form a cavity, in which the raised edge of the first and second ventral segments is received ; second, at the extremity near the suture is a raised longitudinal band marked by transverse strise. The dorsal segments of the hind body are provided with small round stigmata, the one on the apical segment being quite minute ; the ventral segments bear at their upper edge a narrow longitudinal band covered by the epipleura, and the basal one is provided at its posterior margin, at the junction with the second seo-- ment, with a raised prominence which fits into the cavity on the inner face of the elytron as already described ; and the apical ventral segment is bordered by a sharp thin lamina. The legs are slender, they are not modified for swimming by any flattening, incrassation or dilatation ; on the other hand they are provided with a very elon- gate conspicuous ciliation ; the front tibise bear two elongate stout spurs, apparently very near to one another, but really inserted on the posterior aspect of the tibia, the inner one above, the outer one below the articular cavity ; both the outer and the inner edges of the tibia are ciliate, and the outer one besides is armed with fine spines. The middle legs are rather elongate, and are not very dissimilar to the anterior ones. The hind legs are elongate and slender, each side of the tibia is furnished with long cilise, and the upper and under borders of the slender tarsus are likewise greatly ciliate ; the tarsus is twice as long as the tibia, and when the ciliae are carefully spread out it can be seen that the lower face of the tarsus is not an edge, but a narrow distinct sole ; the two terminal claws are moderately long and nearly equal. The male anterior and middle tarsi are elongate and slender, but still distinctly dilated and incrassate ; the elongate basal joint becomes broader at the extremity, and underneath is furnished at the apex with a dense glandular pubescence ; the 2nd and 3rd joints bear a similar pubescence, the 4th joint is quite visible, but small, the 5th elongate, about as long as the basal one. The individuals of this genus possess the faculty of stridulating, and the sound produced is I believe more powerful than what is made by any other beetle : it is 5 O 2 830 On Aquatic Carnivorous Coleoptera or DytiscidcB. called forth by the scraping of the sharp upturned edge of the last ventral segment against the two raised fde-like bands which I have already described as existing on the inner face of the wing-cases. This apparatus is not of itself however sufficient to produce a sound of such power as that given forth by this creature, and there is little doubt that it is rendered much more effective by the pecuhar method of locking the elytra to the sides of the hind body. At the spot where the ventral segments are strongest (viz., the part of the side where a horny raised process traversing the in- ternal face of the first ventral segment abuts) a prominence fits into a large narrow cavity formed by the peculiar process previously described ; on the inner face of the wing-case the coadaptation of these parts is of the most perfect nature, and a locking together of the wing-cases and the ventral segments of a very remarkable character is the result ; when sound is to be produced it is necessary that the insect should greatly bend forward the terminal ventral segment, otherwise it could not reach the file ; by this pressure a great strain or tension is produced at the base of the ventral segments, and by means of the lock just described this is transmitted to the elytra, which are thus thrown into a state of tension perfectly comparable with that of a stretched violin string, and when the file on the stretched elytra is scratched a very powerful sound is produced ; this structure is of the most perfect character ; the very act of commencing to make a noise tunes the instrument that is to produce the noise. The geographical distribution of Pelobius is interesting ; three species are known, one occuring in Europe, but not known beyond its limits (except at such points as Tangiers) the other two peculiar to Australia. The Australian species are structu- rally, and in appearance, excessively similar to the European one, but are distin- guished by a slight structural peculiarity, inasmuch as the scutellum is largely exposed in the European species, nearly concealed in those of Australia. I do not think any more instructive animals exist than these Pelobii, and when entomology receives from able men the full amount of attention it deserves, I doubt not that highly important results will be obtained from their study. I think it would be natural that Pelobius should be classed with the Carabidse rather than the Dytiscidse ; it is in fact purely a Carbideous insect with modifications to enable it to live in water : I do not mean to say that this phrase would be inappli- cable to true Dytiscidse ; but what I intentl is this — if we look upon all DytiscidaB as modified Carabidse, then we may say that in true Dytiscidae the modifications for aquatic existence are predominant in the whole external organization, whereas in Pelobius the Carabideous structure is still predominant. 1 believe investigation will show that the ancestors of Pelobius were formerly Carabidse not very difierent to the Carabidee around it, and only became dwellers in water after the species had reached a comparatively mature stage of adaptation for existence on land : whereas true Dytiscidfe became dwellers in water at a much earlier period of their ancestral On Aquatic Carnivorous Coleoptera or Dytiscidce. 831 record, when they were in a stage of evolutiou more primitive than that of any Carabidife now remaining to us. Embryological studies may here give us important assistance. The following brief recapitulation will show the justice of this assertion. It has already been shown by Schaum and others that Pelobius has the head of Carabidse, besides this its antennae approach more nearly to those of the Carabidse than to those of any Dytiscidfe, except the spurious Dytiscid, Amphizoa : the prothorax is quite that of Carabidse, except that the prosternal process connects with the metas- ternum and even this character is not foreign to Carabidas. (Compare Cyclosomus). The mesosternum is absolutely that of one division of Carabidae. The metasternum is that of Carabidse, and possesses behind the transverse stituie that exists in the majority of Carabidse, but in no Dytiscidse, except the spurious Dytiscid, Amphizoa. The hind coxse are those of Carabid^, with some slight modifications, viz., that they are a little increased in size, that their internal laminse are accurately co- adapted (instead of touching only at one point), and that they are marked by an elon- gate excision for the play of the swimming leg, permitting cf a greater movement of the trochanter in one direction. The legs are those of Carabidse except that they bear cilise. The genera] form is foreign to Dytiscidse, for it is tub-like and does not show that evenness of outline conspicuous in the water beetles ; the sculpture too is that of Carabidse rather than that of Dytiscidse. It seems clear then that Pelobius cannot be satisfactorily classed with the Dytiscidse ; and it is equally clear that it is a Carabideous insect havino- consider- able modifications to adapt it to move in water. It is therefore only included provisionally in my classification of Dytiscidse. Although I think Pelobius may be admitted among the Carabidaj, it will be there an absolutely isolated form. In the present state of knowledge of organic nature no animal having any affinity whatever to these three species can be pointed out. The isolation of Pelobius and the geographical distribution of its component three species are in themselves facts of much interest, for it is almost impossible to suppose that there can have been developed both in Europe and Australia absolutely ah initio animals which, notwithstanding their widely different environment have evoluted into a similar form which is absolutely isolated from all other known forms. It is almost impossible to suppose this, and we cannot but believe that the European species and the Australian species lived during the greater part of their ancestral record side by side, and only became separated from one another when their present structure was comparatively nearly established. It being then quite probable that the Austi'alian species and the European species formerly had a common habitat, it will be an interesting question to consider at what period of the world's history this could have been the case. Huxley has already suggested an answer to this question 832 On Aquatic Carnivorous Coleoptera or Dytiscidce. by stating the probability that in the Triassic or an earlier epoch the land of the Australian continent was continuous with that of the Arctogreal continent. If that be the case and if the Pelobii have remained almost without evolution since that period, it is clear that we must go back in the world's history to a period of enormous antiquity in order to find a time when Pelobii shall have been httle different in their structure from their nearest allies. In actual fact the study of Pelobius does not suggest any belief in the theory of descent from ancestors common to it and other beetles, but rather tends to convince us of its absolute isolation. If, however, we decline to imagine that the European and Australian Pelobii have remained nearly the same in structure since their separation from one another in the Triassic epoch, and prefer to believe that they have evoluted much since their separation, we must in that case admit that extensive processes of organic evolution may be carried on in the most distant parts of the world and may extend over a large portion of the world's history and yet result in the production of almost iden- tical structures ; an admission which would render nearly worthless all that has been written on the subject of geographical distribution, based on the theory of descent from common ancestors. I myself consider that on the whole this second alternative is perhaps the more probable ; I can see no sufficient reason for supposing that the process of evolution in these creatures has been entirely checked since the Triassic epoch, but I can well suppose that it has gone on, though probably very slowly, since that period, and that the Australian and European forms have not diverged much from one another because the laws of growth or evolution are radically the same in all organisms, and because the environment limiting and regulating those laws has been practically nearly the same in both, notwithstanding their wide geographical separation. In order to derive full advantage from the study of Pelobius it is not at all necessary to believe in the theory of the descent of distinct sjjecies from a common ancestor ; the only hypothesis necessary to an understanding of all the facts are first that the laws of growth (evolution being a form of growth) are fundamentally the same in all organisms, and second that similarity of environment limits and regulates these laws so as to produce conformably similar results on similar organizations. Whatever we may think on these points one thing is quite clear, viz., that though Pelobius shows differences from Dytiscidfe of such a nature that those who support the theory of descent would point to it as a proof of the correctness of their theory, yet there is not the least reason for believing it to stand in an ancestral position to any known Dytiscidae. The only relation of this kind that could be suggested with the least approach to credibility is between it and Colpius ; but an examination shows that though in certain highly important points the approximation is very great between the two, in other points they are as distinct and widely separated as are any two Dytiscidae : and the more I have become acquainted with the On Aquatic Carnivorous Coleoptera or Dytiscidce. 833 structures of the two, just in that proportion has the theory of genetic relationship between them become incredible. Now as Pelobius stands in relation to Carabidse and Dytiscidas as Archseopteryx does (or did) to birds and lizards, it is quite clear that most interesting fossil does not any more prove that birds are descended from lizards, than Pelobius proves that Dytiscidee are descended from Carabidse, or Carabidse from Dytiscidae. I. 2.— Genus NOTOMICRUS. {Vide p. 260.) The four species forming this aggregate, are the most minute of the Dytiscidae and among the smallest Coleoptera, the length attained being only about 1 m.m. The form is rather depressed, the surface extremely polished and shining, without punctuation or pubescence. The antennse have no thickening of the middle joints, and are short and simple. The anterior coxaj are minute and placed at a considerable distance from the front of the thorax ; the prosternal process is quite small and is rounded behind. The anterior tibice and tarsi are sinq^le, the former with scarcely developed spur, the latter with the basal joint not notably elongate. The breast is excessively polished so that no trace of the suture between the hind coxa and metasternum can be detected. The coxal processes are slightly prolonged towards their outer hinder angle, the coxal cavities are slightly separated, with the coxal notch very minute and narrow. The swimming legs are excessively feeble, and the hind tarsi are very slender, longer than the tibiee. The genus is readily distinguished by the simple anterior legs, by the obliterated suture between the coxa and metasternum, and by the very feeble swimming legs. I have not been] able to see the palpi, nor to ascertain well the details oJ' the structure of the tarsi. As it stands at present the genus is divided between Australia and South America ; but possibly one of the two species from the latter locality may be found to be sufficiently difierent from the others to justify a new generic name being formed for it ; it has the swimming legs much less elongate and slender ; other species will no doubt be discovered, and this may admit of the characters being correctly formu- lated. At present I cannot pronounce an opinion on the relations of this genus to the other genera of Noterini and I shall therefore leave it isolated in the second synthesis ; I think it probable that this course will prove to be the natural one, even after the structure has been more completely ascertained, for I very much doubt whether it has any close approximation to Hydrocoptus, or any other form yet brought to light. 834 On Aquatic Carnivorous Coleoptera or DytiscidcB. I. 3.— Genus HYBROCOPTUS. {Vide p. 2G1.) This aggregate is formed by five species ; the individuals are of quite small size^ (only 2 m.m. long), oblong-elliptic, and transversely c(>nvex in form, without pubescence and of a yellowish colour, with the elytra a little darker, and subject to bein" marked with very indefinite large yellow patches, or vittse. Their antennae are short and rather stout and very nearly simple, the middle joints being just visibly broader than the others. The labial palpi are not dilated, although their apical joint is just visibly thicker than the others. The prosternum in front of the coxae is rather large, and along the middle is in one plane from the front to the termination of the prosternal process ; this latter is small and narrow, its extremity obtusely acuminate. The front tibife are moderately stout anrl bear a few Jong spines or setae on the outer edge, and are armed at the apex with two distinct spurs one of which is longer than the other and very slightly curved; the front tarsi are simple and slender, and I believe without sexual difference : the hind coxae at their insertions are very distinctly separated. The swimming legs are slender, the hind margin of the femora furnished with a few distant short setse, which scarcely extend to the apex ; the tibiae are slender; the tarsi slender, about as long as the tibiae, terminated by the two small equal, curved claws. The species assembled under these characters may perhaps prove to form more than one genus ; Nos. 8 to 10, have the hind coxal processes but little developed, their outer apices being neither produced nor acute ; the other two species I have only been able to examine very imperfectly ; H. bivittis has the coxal processes more developed, so that their produced outer apices are very acute ; while H. seriatus appears to be intermediate be' ween this latter species and the others in this respect. As it stands, the genus is renresented in Australia, the Indo-Malay region, and Madagascar. The genus is interesting from the analogy it displays with Hydrovatus ; an analogy which evidently arises from the two being in an approximately similar stage of evolution. We have in Hydrocoptus, the characteristics of the higher .genus Noterus displayed in a far lower stage of evolution ; I liave not however associated the genus with Noterus in the second .synthesis, but have at present left it isolated ; it seems to me probable however that it is really connected with the Noterini, by Pronoterus as an intermediate form, and if so the genus will be correctly placed in the Noterini ; as however I have been unable to find any trace of a curved spur on the front tibia, and as this character is so prominent a feature of the other Xoterini, I have not associated Hydrocoptus with them at present. The name liydi-ocoptus has never hitherto received any definition, although it was proposed in ISoo, by Motschoulsky : in his Catalogue of Hydrocauthares de la Russie, he included under Hydrocoptus, the greater part of the European Hydro- pori; but in 1859, he described three species of the aggregate I am at present treating of under the generic name of Hydrocoptus (Etudes Ent. 1859, p. 43, 44) ; and I have On Aquatic Carnivorous Coleoptera or Dytiscidw. 835 thought it justifiable under these circumstances to use the name for the aggregate in which the species just referred are included, but as Motschoulsky never attempted any definition of Hydrocoptus, and included under it both Hydroporides and Noterides, his name had better not be cited in connection with it. I. 4.— Genus PROXOTERUS. {Vide p. 263.) The unique species is of small size ; its individuals only attain 2 m.m. of length, and their appearance is that of a small parallel Noterus. The anterior tibise are short and broad, and their outer angle is distinctly spinose ; at the inner angle they have a minute spur, and a second more elongate one, this latter is curved : the basal joint of the front tarsus is a good deal incrassate. and elongate. The last joint of the labial palpus is dilated ; the presternum is straight from the front margin to the end of the prosternal process; this is of moderate size, with its ter- minal angles rounded, but is truncate at the extremity : the interior laminae of the hind coxae approach very close to the middle coxae, and the wings of the metasternum are quite small ; the suture separating them from the hind coxae is quite distinct. The coxal processes are almost truncate, their outer angle being scai'cely at all pro- duced ; the coxal cavities are almost contiguous, and no evidence of their not being absolutely so can be seen without dissection. The swimming legs are moderately well developed, the tibiae being very distinctly flattened and incrassate, so as to be much broader than the tarsi, these latter are a little longer than the tibiae, their basal joint elongate, considerably longer than the three following ones together ; the two claws are short, and rather stout, equal, curved. This is an interesting form, apparently intermediate between Hydrocoptus and Noterus : it has quite the appearance of the Hydrocopti. I. 5.— Genus SYNCHORIUS. {Vide p. 264.) This aggregate consists of six species, Avhose individuals have the appearance of small Noteri, but when a punctuation is present on the wing-cases it is of a very peculiar kind, and gives rise to an appearance of asperities, rather than of round depressions. The antennae are slender with the terminal joints more elongate tlian the basal ones. The anterior tibiae are rather slender, with the outer margin densely set with very short thick ciliae, the outer apical angle has almost disappeared, the inner one is furnished with a slender elongate curved spur, or hook : the basal joint of the front tarsus is very largely developed. The prosternal process is short, broad, very rounded behind, and is as it were continued forwards between the coxae to near the front margin of the thorax, and becomes quite gradually and gently obsolete there. The suture between the hind coxa and metasternum nearly .touches the middle coxa ; the coxal processes are much developed, and produced at their outer angles ; the hind coxal cavities are contiguous ; the swimming legs are TBANS. ROY. DHB. SOC, N.S., VOL. n. 5 p 83(3 On Aquatic Carnivorous Coleoptera or Dijtiscidce. highly developed, the femora and tibiae being broad ; their tarsi are moderately stout, quite as long as the tibiae, the basal joint as long as the three following ones together ; the femora on their lower face are marked with a series of punctures, very distant from the hind mai-gin, and not setii^erous. The middle legs also are broad. So far as yet known the genus is confined to Madagascar and tropical Africa. I have only been able to study it in a very imperfect manner, but it appears to me very distinct from Noterus, by the simple slender antennae, the broader swimming legs, the less developed anterior tibiae, which, however, have a greater development of the apical spur, as well as by details of less importance. I. G.— Genus NOTERUS. {Vide p. 265.) The six species composing this aggregate have a peculiar facies, being transversely convex above, flat beneath, and much narrower behind than in front ; they have an extremely polished surface, with a greater or less development of isolated punctures towards the posterior part of the elytra. The antennae are liable to extreme and extraordinary sexual developments ; in the female they are moderately stout, with one or more of the middle joints slightly broader than the others, while in the male they are more or less incrassate, and one or more of the middle joints become extremely developed and of strange form. The last joint of the labial palpus is dilated and notched. The prosternal process is moderately broad, with its apex obtuse I the front coxae are placed at a considerable distance from the front of the prosternum. The front legs show great sexual differences ; in the females the anterior femora have a slight curved emargination on the front of the lower margin of the femur; in the male this notch is much larger. The tibia has its outer margin densely set with short ciliae, and its outer apical angle completely rounded ofi^ ; in the male the tibia is broader than in the female, and its inner margin bears a large angular prominence near the extremity ; the tarsus is inserted in a large cavity on the posterior face of the tibia, and from this spring two spurs, one placed near the inner margin scarcely projects beyond the apex of the tibia and easily escapes observation, the other one is much longer, and is gently curved, and it is directed somewhat towards the outer margin and projects much bej'ond the tibia, being usually closely applied to the inner edge of the basal joint of the tarsus. In the female the basal joint of the tarsus is stout, and as long as the three following joints together : in the male it is extremely large and incrassate. The suture between the hind coxae and the metasternum is quite distinct, and nearly attains the middle coxal cavity. The coxal processes are largely developed, and a good deal prolonged at the outer angles : thccoxal cavities almost quite contiguous. The swimming legs are ratherstout, the femora traversed by a series of punctures placed parallel with the hind margin. On Aquatic Carnivorous Coleoptera or DytiscidcB. 837 and beai'ing each a fine seta which does not project beyond the margin, these setse are in some species more numerous and crowded together at the extremity and there collected into a kind of depression on the face of the femur, but do not project beyond its margin. The tarsus is a little longer than the tibia and is terminated by two equal claws, the basal joint is about as long as the three following ones together. The species of this genus as yet known are peculiar to the European and Mediterranean region with one in Japan. Noterus Irevis is the highest, Dytiscus clavicornis the lowest species of the genus ; there is a very great difference between the development of the swimming legs in these two forms : the former species shows also the o-reatest development oi the sexual characters, and is remarkable also for the accumulation of setce at the extremity of the hind femora ; in this latter respect N. japonicus is intermediate between it and the other species. The genus presents a very interesting peculiarity, consisting in the development of patches of dark colour, on the undersurface of the body and legs in the male sex only. I. 7.— Genus COLPIUS. {Vide }x mi.) This is an isolated insect, of subhemispherical form, but nevertheless acuminate behind : the surface is dull, the upper face covered witli a dense fine sculptui'e, the lower with an extremely coarse irregular sculpture. The antennae are rather slender and subserrate internally. The apical joint of the labial palpus is dilated and notched ; the prosternal process is large, and broad, not truncate behind, but only very obtusely acuminate, it is bordered by a raised margin, and is continued forwards quite on one plane, till at the anterior margin of the prosternum it presents a vertical face ; the anterior transverse band of the prosternum is small, the rather large coxoe being placed near the front margin. The middle coxae are small and globose ; the metasternum seems to be separated from the hind coxa by a nearly straight transverse suture, which however is rendered extremely obscure by the coarse sculpture ; the coxal [jrocesse.s are very broad, and become broader behind, but their outer angles are very little produced backwards, the coxal cavities are separated by a rather broad space. The epipleurae of the elytra are very broad at their basal portion, and continue distinct, although narrow, till near the extremity of the body. The front legs are extremely modified, and most peculiar : the femora are subcylindric and a little curved ; the tibiae are articulated and shaped in such a manner that what should be the outer edge is the lower one, and the inner edge is the upper one, the natural front face look- ing outwards ; the upper edge is rounded and polished and terminates in an elongate, stout, acuminate hook, this appears to be continuous with the tibia and the tarsus has the appearance of being inserted at a distance from the extremity. The basal joint of the tarsus is about as long as all the other joints together, and is in the male much incrassate. The intermediate legs are feeble. The swimming legs are 5 P 2 838 On Aquatic Carnivorous Coleoptera or Dytiscidce. very little developed, and quite feeble, the hind margin of their femur bears some very elongate setae at the apex, the tarsi are rather shorter than the tibiae, and their basal joint is longer than the three following ones together. This insect is peculiar to North America. It is an interesting example of very different stages of evolution of portions of one organism ; the very feeble and low organization of its swimming legs contrast very forcibly with the extremely high differentiation of the anterior legs. It is probably a very inactive creature : and apparently rare, as 1 have not been able to obtain a specimen for dissection. I. 8.— Genus SUPHIS. ( Vide p. 268.) Three species is all that at present is known to constitute this aggregate ; their individuals are of very peculiar form, being extremely convex above, and of very short oval form, attenuate and acuminate behind; the general colour is obscure yellowish, with the elytra darker and obscurely spotted ; the upper surface is closely punctured, and on the undersurface the breast is coarsely sculptured. The antennae are rather long and slender, the apical joints subserrate internally. The prosternal process is broad, truncate, or very nearly so, behind, and is continued forwards between the coxae, but is somewhat gradually flexed towards the front, so that it only presents in front a very small vertical face ; the large anterior coxae are globose, and extend nearly to the front of the thorax, which presents only an extremely small band in front of them; the metasternum is separated from the hind coxa by a suture ■which departs but little from a straight transverse line : the coxal processes are very broad, nearly parallel sided, and are nearly truncate behind, the coxal cavities are separated by a rather broad space, which is marked off on each side by a broad, rather distinct, coxal notch. The front legs, and the other characters are much the same as in Colpius. The genus is restricted to the tropical parts of the New World. I. 9.— Genus CANTH YDR US. ( Vide p. 269 .) This aggregate consists of about forty species ; they are small insects attaining only about 3 m.m in length, they are short in form, very convex above, much acuminate behind, frequently variegate in the colour of the upper surface, and this may be either very polished and free from sculpture, or on the contrary coarsely punctured. The antennae are very short, slender, frequently with one or more of the intermediate joints a little larger than the others. The last joint of the labial palpus is greatly dilated and obscurely notched or emarginate; the prosternal process is rather large and a little longer than broad, it is nearly truncate behind, the angles being nearly rectangular, the front coxae are not greatly separated from one another, and there is a moderately long anterior band of the prosternum ; the On Aquatic Carnivorous Coleoptera or Dytiscidce. 8-19 middle of the prosternum shows no [)erpendicular face in front in the middle ; the pectoral prominence is very coarsely sculptured while the adjacent lateral parts are smooth; the suture between the hind coxa and metasternum approaches near to the middle coxa ; the coxal processes are highly developed and greatly prolonged be- hind, the pi'olonged angles being rendered sharply acuminate by bearing some rigid ciliae; the swimming legs are rather slender, the femora and tibiifi but little flattened or laminate; the former bear a well developed group of cilioe at the extremity of their hind margin; the tarsi are about as long as the tibiae, their basal joint as long as, or longer than, the three following ones together. This genus has been mixed with Hydrocanthus, but was separated by Crotch so far as regards the North American species; he suggested for it the name of Suphisellus, but not in a formal manner — only as it were hypothetically, and I have thought it oil the whole better to use a new name. It is very distinct from Hydrocanthus, by the small size, the greatly narrower prosternal process, and the feeble swimming legs. The species seem to be found in the warmer parts of both hemispheres, but so far -as yet known are absent from Australia. I. 10.— Genus H YDROCAN'THUS. {Vide p. 279.) This aggregate consists of about twelve species ; they are the most highly organised of the Noterides, the size varies between 4 and 8 m.m. of length, the form is somewhat elongate, very acuminate behind, very convex transversely above, the surfiice is extremely polished, and is never variegate by spots or stripes. The antennas are slender, and are rather short, the middle joints of the antennae often distinctly a little longer than the others, but scarcely broader. The terminal joint of the labial palpus is excessively dilated, but a notch or emargination can scarcely be detected on it. The front coxse are rather broadly separated, and the prosternal process behind then becomes extremely broad, so that it is frequently much broader than long, it is nearly truncate behind, and its angles are either rectangular or acute ; tiie front band of the prosternum is rather large, and does not present any perpendicular face in the middle ; the pectoral prominence is very highly developed, so that there is formed as it were a continuous prominent platform extending along the middle of the body from the front coxse to the hind legs, and becoming broader as it extends backwards ; this prominence is more or less punctate, while the adjacent parts are smooth ; the suture between the metasternum and hind coxa, does not approach very near to the middle coxa ; the coxal processes are highly developed, and greatly prolonged behind, the prolonged angles being rendered acute by a group •of rigid ciUse : the swimming legs are highly developed, the femora and tibiae being- much incrassate and flattened, the former are traversed along the middle of their lower face with a series of punctures parallel with the hind margin, and are furnished at the extremity of their hind margin with an extremely highly develojied 840 On Aquatic Carnivorous Coleopiera or Dytiscidie. group of prominent cilise ; the tarsi are as long as but much more slender than the tibial : the middle leers also are a s^ood deal incrassate and laminate. These insects are distributed over a broad zone of the tropics extending from Northern Australia, through the Indo-Malay region, Madagascar and tropical Africa, to America, and in this latter part spread northwards to the United States, where a species is found even so far north as Massachusetts. The Australian species is decidedly a lower, or less evoluted form than any of the others. I. 1 1.— Genus MACRO VATELLUS. ( Vide p. 282.) This aggregate consists at present of seven species. They are insects of rather elongate form, and equal in size the largest Hydroporini, attaining 7 or 8 m.m. of length ; the outline of thorax and elytra is very discontinuous, the colour is obscure and scarcely variegate, the upper surface is very densely punctured. The prosternal process is broad and very abruptly bent, and terminates in a point which is concealed between the front of the middle coxse ; these latter are perfectly contiguous, and the mesosternal fork cannot be perceived. The mesosternum is placed at a very obtuse angle with the metasternum, so that it is extremely exposed, between the pro thorax and metasternum ; the posterior coxae are large ; the coxal lines are divergent and widely separate in front, but approximate behind, they do not extend quite to the apices of the coxal processes, and their indistinct terminal portion is quite evidently turned outwards, and the coxal borders are much prolonged in the transverse direction ; the posterior trochanters and venti'al sutures are nearly normal : the suture between the second and third segments is not quite obliterated in the middle. The sexual differences seem to be very slight. The species are found only in the warm parts of the New World, and are extremely rare in collections. I. 12.— Genus VATELLUS. {Vide p. 285.) This is an autogenus; the insect is of Hydroporoid form, but with very dis- continuous outline, and very elongate anterior tarsi, it is of obscure colour, with very densely punctate upper surface. The prosternal process is rather elongate, and is abruptly bent, and terminates in a point concealed between the fronts of the middle coxae ; these are quite contiguous and exposed ; the mesosternum is placed at a very obtuse angle with the metasternum, and in consequence is largely visible between the prothorax and metasternum; the hind coxae are large, the coxal lines are rather strongly elevated, a good deal divergent in front, approximate behind, and extending quite to the extremity of the coxal processes, and not turned outwards ; the coxal border has a large extension in the transverse direction, though very short longi- tudiiiivlly. The posterior trochanters are thick and globular at their extremity. On Aquatic Carnu-orous Coleoptera or Di/tiscicke. 841 The ventral sutures are very deep, that between the second and third abdomuial segments veiy deep even in the middle. The sexual distinctions are very slig-ht. The only species known has been found in Cayenne. I. 13.— Genus DEROVATELLUS. {Vide p. 28G.) This is an autogenus ; the insect is of the size of an average Hydroporus, and has much the appearance of the species of that genus ; the upper surface is densely and rather finely punctured. The prosternal process is short and broad, rhomboidal in form, with its extremity received between the middle coxiB ; these are exposed, and contiguous. The mesosternum is placed at a slightly obtuse angle with the metasternum, and is not much exposed : the coxal lines are a little divergent in front, but not much separated, and are indeed approximate through their whole length, they are however distinctly turned outwai'ds in their terminal portion ; the coxal border has very little extension in the transverse direction. The posterior trochanters are normal, as are also the ventral sutures, that between the second and third segments being quite obliterated in the middle : the claws of the front tarsi are excessively minute. The sexual distinctions are very slight. The insect inhabits tropical America. I. 1 4.— Gen us LA CCOPIilL US. ( Vide p. 2 8 7.) About eighty species compose this aggregate. They are insects of small size, the largest attaining only 6 m.m. of length ; the upper surface is frequently moi'e or less variegate, though generally in an indefinite manner, and its sculpture is either slight, or wanting, giving place to a very polished surface, the underside is free from sculpture except that there are elongate, oblique scratches on the ventral segments ; the form varies from nearly elliptical to an oval, and is never very convex, the outline is very continuous. The head is very short and broad, the portion in front of the eyes being extremely short, the eyes of moderate size have their circular inner outline only very obscurely infringed on at the insertion of the antennae : the head in front shows no trace of a raised margin, its emarginate-truncate front edge being very thin and closely applied to the exposed labrum. The antennse are slender and quite symmetrical, showing no peculiar forms or sexual differences ; the parts of the mouth are small and the palpi simple. The thorax is without any lateral mfirgin, and almost without any punctures along the margins. The scutellum is quite concealed. The prosternum is very small, the small, conical, front coxae being placed very near the front, so that there is only a verj; short transverse band in front of them ; the prosternal process is remarkably small, very acuminate, much compressed, and frequently its apex is prolonged so as to form a very slender, elongate, excessively 842 On Aquatic Carnivorous Coleoptera or Dijtiscidce. acuminate spine ; the front coxaj are very ap[)roximate, and the presternum in front continues the plane of direction of the prosternal process ; the mesosternum is placed almost completely at right angles to the metasternum ; its epimeron is laro-e, and very broad at the metathoracic-episternal angle ; its fork is small and inconspicuous. The metasternum is elongate in the middle, but excessively reduced at the side ; it approaches very near to the middle coxa, and is afterwards deflexed outside the anterior border of the hind coxa, forming a slender very curved band ; the iuter-coxal process is very narrow owing to the great approximation of the middle coxae, and is curved up in front to form a minute but perfect articulation with the mesosternal fork, it is marked by a very fine groove (of variable length) for the i-eception of the extremity of the prosternal process. The hind coxa? are of enormous size, and extend greatly forwards so as to possess an extremely arched anterior border ; the coxal lines are of peculiar form, they are very distinct, and commence in front at the apex of the metasternum being tliere much approximate to one another, they extend backwards, diverging from one another till each reaches the outer hind angle of the process ; the two processes are completely soldered quite to the hind margin, which thus presents a truncate edge ; the coxal border is very distinct and definite, it is broad in front but terminates in a point behind : the coxal cavities are completely contiguous and very much concealed and protected by the processes ; no coxal notch can be detected, unless a slight sinuation of the hind margin of the process be considered to represent it. The anterior and middle legs are feeble, their tarsi conspicuously 5-jointed and without any trace of lobing of the third joint. The swimming legs are highly developed and powerful, their femora are broad and are laminate at their hinder outer angle, which is nearly a rect- angle and well marked ; the tibiae are short and stout, much shorter than the femora, and terminated by two sublinear highly developed spurs, which are not acuminate, but are minutely emarginate at the extremity; the tarsi are of peculiar and characteristic form ; when their outer or upper face is observed it is seen that the hind margin of each joint deviates greatly from a straight line, the outer portion of the joint being produced backwards, so as to form a kind of lobe projecting over the following joint ; the basal joint is about as long as the two following ones together, the terminal one is broad, and bears a single short stout claw. The abdominal stigmata are all small and circular. The male tarsi are but little developed, sometimes it is not easy to distinguish any difference between their structure and those of the female ; they show very little dilatation and when they are thickened the incrassation is quite as great in the vertical as it is in the horizontal direction ; no sexual sculpture has been detected in the female. An interesting feature in certain species of this genus is the existence of a stridu- iating structure consisting of a curved series of grooves on the hind coxa ; these are played on by a single, very obscure elevation situated on the anterior edge of On Aquatic Carnivorous Coleoptera or Dytiscidce. 843 the upper surface of the hind femur ; this structure is more developed in the male than in the female, and is indeed entirely wanting in the latter sex of certain species in whose male individuals it is conspicuous. It exists in various states of delicateness, and certainly the sound produced must be at the best very feeble, probably inaudible to the human ear, while in certain species where the apparatus is extremely fine it seems to me impossible that any sonorous vibration could be produced capable of affecting a nerve, unless this be assisted by a highly developed apparatus equal even to that of the human ear. The species of Laccophilus are distributed over all the warmer and temperate parts of the world, except the Pacific Islands and New Zealand ; the stridulating species are confined to the New World with the solitary exception of the European Dytiscus interruptus, and it is quite probable that this species ultimately may be found to be also a North American one. I. 15.— Genus NEPTOSTERNUS. {Vide p. 317.) Under this name I have isolated a single species, in many points closely allied to Laccophilus but in others singularly different therefrom ; it is an insect of polished surface, of the size, and with much of the appearance, of a Laccophilus, of a yellowish colour, with the elytra dark, marked with large yellow marks : the thorax has an obscure marginal series of punctures in front, the ventral segments are destitute of scratches. The broad head is moderately elongate, and the eyes are placed so that a consider- able space separates their hind margin from the front margin of the prothorax. The outline of the thorax and elytra is perfectly continuous, and the hind angles of the thorax are much prolonged backwards so that they are extremely acute, in fact they form a long slender spine ; the hind margin of the thorax in the middle is straight not accuminate as in Laccophilus ; the prosternum in front of the coxae is not quite so short as in Laccophilus, and the coxae are not so approximate, while the prosternum behind them expands into a trispinose process, the middle spine of which is longer than the two lateral ones ; the front coxae are very small. The wings of the metasternum are excessively slender, the hind coxa being in fact very little separated from the middle coxa ; these are more widely separated by the inter-coxal process than they are in Laccophilus. The hind coxse though large are not so enormous as in Laccophilus, and their front border forms a very much flatter arch. The coxal lines are strongly elevated and remarkably distinct ; the swimming legs are more slender than in Laccophilus ; the spurs of their tibiae are slender and very acuminate, and the lobing of the joints of the comparatively slender tarsi is much less distinct than it is in Laccophilus. This, at present isolated ci-eature, is found in Madagascar and Zanzibar. TBANS. HOT. DUB. SOC, N.S., VOL. II. i Q 844 On Aquatic Carnivorous Coleoptera or DytiscidcB. I. 1 G. —Genus A MPHIZOA . ( Vide p. 318.) Tliree closely allied species form this aggregate. The}^ are insects of somewhat elongate, moderately convex form, the outline much interrupted at the junction of the thorax and elytra ; the colour is an uniform dull black, and the surface is sculptured with a coarse, indefinite, but close punctuation. The head is rather broad and short ; when in position in the thorax its breadth is about one-fourth greater than its length from the front of the thorax to the front of the clypeus, and when extracted the bi-eadth is still a little greater than the length : the eyes are rather small in proportion to the size of the head, they are slightly convex and prominent, and occupy chiefly a lateral position, their encroach- ment on the area of the upper and undersurfaces being but small. The clypeus is separated from the posterior part of the head by a fine suture, distinct across the whole width of the head, the clypeus has about twice the area of the exposed portion of the labrum, and is quite continuous with the plane of that part ; the anterior angle of the clypeus is not folded under in front of the antennal cavity. On the under surface the transverse sutures on the lateral portions of the head are very difficult to trace. The mentum is united with the base of the head by a very fine nearly obliterated suture, and is extremely large, and extends forwai'ds quite as far as the front of the labrum, the mandibles and maxilliB being completely covered by its large lateral wings ; the outer lobe of the maxilla is curved and palpiform, but is not divided by any articulation. The antennse are short and stout, and of simple construction, their basal joints are punctate or porous ; this punctuation becomes more indistinct on the terminal joints so that the outer ones are nearly smooth and shining ; there is no pubescence to be seen on any of the joints. The prothorax has the pronotum flat, the sides coarsely and irregularly crenulate so that it would be incorrect to say that there either is or is not a lateral margin. The prosternum is rather large, the length of the band in front of the coxa being equal to that of the coxal cavity, along the middle in the longitudinal direction it is flat, and shows no trace of any thickening along the middle, it is prolonged back- wards between the rather widely separated coxse, so as to form a flat, short, broad, prosternal process, the extremity of which is truncate-rounded : the side pieces are large, the suture between the anterior and posterior of them is in some inchviduals difficult to detect, but when seen it is found that the posterior piece is of large area, probably more than half that of the anterior piece. The coxae are suborbicular and rather small. The mesosternum is rather small, and its plane of extension is almost a continua- tion of that of the metasternum, so that in the natural condition the mesosternum is quite visible between the meta- and pro-sterna, its epimera are triangular : thus the general form and relative size and disposition of its parts are singularly similar On Aquatic Canilvorous Coleoptera or DjtiscidcB. 845 to the higher Dytiscidse (such as Cybister), with the exception that the fork by which it terminates below is but little developed. The sternal pieces of the metathorax are rather large and have more than twice the area of the corresponding pieces of the mesothorax. The metasternum projects in the middle in front between the middle coxae to form a broad inter-coxal process ; this meets the apex of the prosternal process but is not impressed with any grove, uor does the apex of the prosternal process extend on to it. At the hind border in the middle there is a short transverse suture. The episterna are narrow behind, but in front are prolonged inwards so as to touch the middle cox*. The epimeron is quite coveredbytheelytron,butondissection isfound to be quite the same as regards its articulations and nearly the same in form as it is in the higher Dytiscidae (Cybister). The hind coxse are rather large, and have fully one-half of the area of the meta- sternal pieces ; they are separated in front from the metasternum by an approximately straight, or directly transverse, suture; this suture is however slightly undulated and its nearest approximation to the middle coxa is at a point which is considerably nearer to the mesial line of the body than it is to the epipleura ; the internal laminae of these coxae are large and are closely applied to one another along the mesial line, externally each is separated in an abrupt manner from the outer or femoral lamina, and the line of separation is in front much directed outwards, and does not reach the metasternum, it is not marked by any definite impressed line so that there is no true coxal border, the articular cavities are widely separated, and terminate internally in such a manner as to form a short broad notch. Hind-body with six visible horny, ventral segments ; the first one interrupted in the middle by the hind coxae, the second scarcely at all infringed on by the coxte, but with its middle part distinctly prolonged forwards, so as to form an obtuse triangle adapted to the apex of the articular portions of the hind coxae : the ventral sutures are all distinct. The scutellum is large, and exposed at the base of the elytra. The wing-case has a well developed epipleura, which is very broad at the base but becomes greatly narrower at the side of the first ventral segment, and continues rather narrow till the commencement of the last segment, where it disappears ; this epipleura is very much inflexed, and very closely embraces (or is coadapted with) the flanks of the undersurface of the body : at the base of the wing-case, on its inner face, there is a free scutellar membrane. The ventral segments have a lateral border, which is clearly divided into two portions, each of which is horny, the upper portion on each segment is about equal in width to the lower, and the pieces on the successive segments from base to extremity continue of about one width, except that on the terminal segment the lateral pieces disappear from the posterior half of the side of the segment. All the legs are elongate and slender, and peculiarly free from ciliae and setae, there exists however a slender band of elongate ciliae placed in a groove on the outer 6 Q J 846 On Aquatic Carnivorous Coleoptera or DytiscidcB. edo-e of the middle tibia: none of the lesfs are in the least incrassate or modified for swimming: and the tibia of each is terminated by two short, subequal spurs. The sexual distinctions are unknown to me, as also are the position and condition of the stiofmata. The above characters are drawn from a specimen of Amphizoa insolens, Lee. Amphizoa is peculiar to California, it is a completely isolated creature and yet at the same time a so-called synthetic type. It has been much discussed whether the genus should be classified in the Cara- bidse, or in the Dytiscidse, or should form a distinct family : and some of the ablest of modern Coleopterists have treated the question. Leconte, the original describer of Amphizoa, considered it the type of a family distinct both from the Carabidae and the Dytiscidae ; Lacordaire classified it among the Dytiscidae, while Schaum described it as a Heteromeroid form of Carabidie, and another entomologist actually described the insect as a member of the Heteromera. I am with Horn unable to detect the least approach to the Heteromera, and think Schaum's opinion quite incorrect. For each of the opposing views of Leconte and Lacordaire much may be said, and I have decided to give Amphizoa a place, but a quite isolated one, amongst the Dytiscidae, for the following reasons : — The peculiarities of the Dytiscidae have been produced in accordance with two main facts of their existence, first that they live in the midst of water, and second that they locomote through and in that medium : while the Carabidse live on the surface of the earth, or do so approximately ; the structural peculiarities of the two families are correlative with this difference of the conditions of existence The antennae of the Dytiscidae are different as regards their sensitive structure from those of the Carabidae because the medium through which the origin of the sensations is conveyed is different ■* so the locomotive organs in the two families act under profoundly different conditions, the legs of a Carabus walking on dry ground have to overcome the influence of gravity and both lift and support and move forward the being at each step ; the Dytiscidae are of nearly the same specific gravity as the fluid in which they live, but are a little lighter than it, and their legs have to act so as to slightly drive down their bearer at they same time as they move it forwards ; the legs of a Carabus find the medium which directs their action only beneath their body, and only a small portion of the limb can come in contact with this medium, while the Dytiscidae have the whole body and leg sur- rounded by the medium ; hence the leg as a lever acts in a different direction, so that it may be quite correctly said the differences in structure of the legs of the Carabidae and Dytiscidae are perfectly in accordance with difl'erences in their environment. * The special reason may be either, that the physical impulses acting on the antennse are not transmitted through water ; or that water in contiguity with the apparatus of sensation is incompatible with its functional activity. Oii A<2(ialio iJainiL'orous Coieoptera or DytiscidcE. 847 Amphizoa shares the conditions of existence of Dytiscidse completely as regards the medium in which it Hvos, but only incompletely as regards its locomotion ; it lives in water coustanLly but does not move through the water, but clings to stones and moves about on them ; (the structure of its i\h\se and tarsi are of themselves sufficient to show that it is not a swimmer or diver) its legs however have not to overcome the influence of gravity, and they become forward propellers, not lifters, and they propel by pushing not against water, but against the surface of the stones beneath or behind them ; the structure of these propellers is therefore a singular melange of the structures of these parts in Dytiscidae and Carabidse, the coxae are modified absolutely in the Dytiscidse direction ; while the other parts of the leg remain absolutely as in the lower Carabidae. Strictly speaking therefore Amphizoa is neither Dytiscid nor Carabid. N^evertheless after this has been granted there presses itself on us this incontrovertible fact, viz., that in most of the points in which Amphizoa departs from Cai-abidai it becomes Dytiscid, to which we must add the important fact that in the structure of its middle coxal cavities it possesses pecu- liarities found in no other beetles except itself and the Dytiscidse. Amphizoa is therefore for me a member of the Dytiscidse, that differs from all other members of the family by its want of means of swimming through the water, and occupies a completely isolated position in the family aggregate. Viewing the matter as a point of synthetical classification I assert boldly and without fear of contradiction this: that Ampliizoa should be united with the Dytiscidse in a synthesis prior to the synthesis that unites together Dytiscidse, Amphizoa, Carabid £e, Hahplidse, and Cicindelidse as one aggregate. Dr. Horn has reviewed the opinions of Leconte, Lacordaire and Schaum, and stated (Tr. Am. Ent. Soc. 1867, p. 158), "with the Dytiscidse, Amphizoa has but little in common excepting the large size of the posterior coxse. The parts of the mouth have but little analogy to those of Dytiscidse." He gives however no further reason for its separation from Dytiscidse ; and I cannot myself consider that the parts of the mouth separate the insect from Dytiscidse; the large size of the mentum is a fact of great interest but evidently of com2:)aratively little importance; the only other point of difference in the trophi from Dytiscid^ is the absence of a division in the external lobe of the maxilla ; but this point is merely a question of develop- ment, for I have no doubt it will be shown that ail the primitive Dytiscidse (and Oarabida^) had an inarticulate external lobe to the maxilla ; and moreover in the neighbouring family Carabidse we find that although the lobe is biarticulate in nearly the whole of its enormous number of species there are yet one or two exceptions in which it is only uniarticulate as in Amphizoa. Further, the parts of the mouth have not been examined in many Dytiscidse, and it is quite possible that some true Dytiscidse may be found to have a simple external lobe on the maxilla. I come to the conclusion then, that Amphizoa cannot be considered a distinct family of Coieoptera from the Dytiscidse and Carabidse, in the same sense as Dytiscidse 848 On Aquatic Carnivorous Coleojitera or Dytiscidoe. and Carabidte are themselves distinct families, and that as its departures from the Carabidse are in the Dytiscidas direction it may be placed with the latter. It is a creature which may be considered to have retained a more primitive condition in certain portions of the organization, (antennge, maxillary lobe, and legs, coxse excepted) than have other members of the Dytiscidse or Carabidje, while its hind coxai and thoracic segments have been the subjects of an evolution similar to that of the same parts in Dytiscida). It is Dytiscid inasmuch as it lives in water, it is Carabid inas- much as it moves on a solid surface in that water ; now as there are no Carabidse having the middle coxal cavities formed as they arc in Amphizoa and as in this respect it agrees with the majority of Dytiscidse, these reasons entitle us to place it with the latter in a natural classification. Note. — I consider that the punctate antennge of Amphizoa may be justly considered a more primitive condition of those organs than the pubescent antennae of '^'arabidse or the glabrous antennae of Dytiscidae, for the following reasons; the antenna} of Carabidse are complex organs of sensation, perfection being obtained by means of punctuation (?), setae, and delicate pubescence,* the simply punctate antennae of Amphizoa are therefore clearly more primitive than the punctate-setose-pubescent antennae of Carabidae. As regards the comparative primitiveness of the glabrous antennae of Dytiscidae and the punctate antenna? of Amphizoa, the facts are not so clear, and it would at first appear that the glabrous antennae of Dytiscidae should be treated as more primitive than the punctate Amphizoa antennae; but there is reason to believe that the antennae of Dytiscidae have been more or less punctate before becoming glabrous ; thus in Pelobius (the most imperfect Dytiscid or Carabo- Dytiscid), the basal joint of the antennae is a good deal punctured, in Scutopterus (S. horni, Crotch) a higher form, a slight punctuation of the basal joint exists, and traces of such punctuation may be perceived even in Dytiscus, while in the highest Dytiscidai (Cybister for example) the antennae are completely polished and free from punctuation. In writing of these insects I consider therefore I am entitled to treat antennae with a punctuation on the basal joints as more primitive than polished, or highly pubescent, antennaj. I. 17.— Genus HYDROVATUS. {Vide p. 321.) This aggregate is formed by the union of about forty .species. The individuals are of small size, and of broad, convex, short, sometimes quite rotund form ; the elytra are more or less acuminate behind, and there is frequently a small spine pi'ojecting from the termination of the body ; the swimming legs are very slender and little developed. The clypeus is large, and overhangs the labrum ; this, how- ever, is seen to be exserted and visible when the undersurface of the head is * I say this without conaidei'ing at all what relation this punctuation may bear to the pits described by Erichson and others as forming part of the sensitive apparatus of the antenniB of the Coleoptera. On Aquatic Carnivorous Colcoplcra or Dytiackkn. 843 ■examined. The prosternal process is broad and short, in fact subtriangular, with the base of the triangle placed behind ; the point of junction with the prosternum is marked by a slight tubercular projection. The middle coxas are rather broadly separated. The hind coxte are about twice as great in area as the metasternum, their upper border subparallel with the lower one, but still, near its outer termination, ■distinctly arched in front ; the hind coxal cavities are not contiguous, and possess a very distinct ojaening or coxal notch, and external to this there is a projecting portion (extra-rimal portion) of about equal width to that of the intra-rimal portion ; tliis extra-rimal portion conceals and protects the outer part of the articular cavity. The coxal lines are very fine, but a good deal divergent in their anterior part. The swimming legs are slender ; their femora are slender, and are rounded at the extremity, their tibiae and tarsi are very slender and very little ciliate, the latter are not compressed laterally, and are terminated by two small, slender, equal, curvedclaws. The front and middle tarsi are very short, four-jointed, the third joint imperfectly bilobed. The elytra have on their inner face a raised ridge, which is somewhat waved near the apex, but is not provided with any articular tongue ; they have a genicular fossa at the shoulder, (or base of the epipleura). The sexual differences are found chiefly in the antennae and in the sculpture ; they are remarkable in a few species, but in the majority are inconspicuous ; it is probable that in some species dimorphism of sculpture occurs in the females, but I am not able to announce this with certainty. The aggregate is very widely distributed on the surface of the earth, but does not occur in the northern regions, and is unknown in New Zealand and the Pacific Islands. The species are very difficult to distinguish inter se, and moreover it is certain that only a small portion of those existing are known to me. Under these circumstances it would be useless to attempt any tabular discrimination of them : comparison of fresh individuals with those already named and described will be, in the present imperfect condition of our knowledge, the only trustworthy mode of determination. Anyone attempting to discriminate the species should note the nature of the margin of the front of the head, and examine carefully the structure of the antennae and tarsi. I. 18.— Genus QUEDA. {Vide p. 336.) A single species is isolated under this generic name. It is an insect somewhat simi- lar in form to the Hydro vati, but exceeds them in size. The characters are to a large extent similar to those of Hydrovatus ; but the head is completely rounded in front, and has a very evenly raised margin, and the labrum is so extremely concealed that on the most careful examination only the long fringes by which it is terminated, and its outer angles, can be detected. The coxal lines are subparallel, the coxal opening is broader and shorter, and the extra-rimal portion is broader and completely 850 On Aquatic Carnivorous Coleoptera or Dytiscidoe. conceals the articular cavity : the ridge on the inner face of the wing-case is broader near the apex and distinctly bisinuate. (So far as 1 can see there is only one verv short claw terminating the hind tarsus, but this requires confirmation.) When fully known I think it probable the departure from Hydrovatus will be found very decided ; it is worthy of note that this interesting form approaches considerably in appearance and in some of its characters to its geographical consort, Pachydrus. This autogeneric species is found in tropical America. I. 19.— Genus HETERHYDRUS. {Vide p. 337.) This autogenus is formed by a species whose individuals have the size and form of an elongate Hyphydrus, and this resemblance is rendered still greater by a similarity in the head and swimming legs to those of Hyphydrus. The head is quite rounded and evenly margined in front, and the labrum is exserted on the under- surface; the prosternal process behind the coxae is very broad and short, and its hind margin forms in the middle so very obtuse an angle that it may be called sub- truncate. The hind coxte are extremely large, and the suture between them and the metasternum is very obliterated; their articular cavities.are widely separated, and quite exposed, being placed external to the broad adpressed coxal process, and not protected by any portion of it. The swimming legs are apparently similar to those of Hyphydrus, even as regards the tarsi and claws. As I have only a single (badly preserved) individual of this creature at my disposal I am unable to ascertain more completely its characters. It appears however to be allied to the South American Pachydrus, from which it differs by the exserted labrum, and by the fact that its hind coxae have their anterior border less arched, and less approximate to the middle coxae. Whether the coxae be soldered with the ventral segments is not ascertained, but in my classification I have taken it for granted that such is the case. This interesting autogenus is found in Madagascar and tropical Africa; 1 have little doubt that other species will be discovered. I. 20.— Genus PACHYDRUS. {Vide p. 338.) Five species form this aggregate ; they are insects of broad and short, rounded form, excessively convex beneath, and without colour variegation on the surface. The head is broad and short, and is rounded and margined in front, the labrum is not visible from the front, but when the undersurface of the head is looked at it is found to be slightly exserted. The prosternum is very small, and has a short, broad — broader than long — process ; this prosternal process is carried forwards between the coxae as a raised narrower process, till it terminates very abruptly, more than lialf way towards the front of the coxae, as an abrupt acute projection. On Aquatic Carnivorous Coleoptera or DijtiscidcB. 851 Middle coxse rather widely separated ; the intercoxal process of the metastenium is slightly emarginate in front, in adaptation to the prosternal process ; the metaster- num is elongate in the middle, and its side wings are extremely slender ; the hind coxae are extremely large, their articular cavities are very widely separated, and are quite exposed and unprotected, being placed quite outside of the broad coxal processes which are adpressed to the level of the ventral segments ; the hind border of the coxsB is completely soldered to, and amalgamated with the basal ventral segment. The hind legs are rather slender, their tibiiB and tarsi not much ciliate, the latter terminated by a stout short claw, (there exists a second claw, but it is so short that it can only be detected by a most careful examination). On the inner face of the wing-case the raised ridge has a very strong double wave near the extremity. The anterior and middle tarsi are small, four-jointed, the third joint bilobed, the fourth joint exserted, and of about the same length as each of the other joints. Although these insects have hitherto been classed with the old world Hyphydri, and not in any way distinguished therefrom, they are really widely different. The soldered ventral segment is of great importance as a distinguishing character, but besides that, the genus has the hind articular cavities more widely separate, and the upper border of the coxas different in form ; the prosternum is still more reduced, while its process is broader and larger, and the inter-coxalband is prominent; the anterior tarsi are formed as in Hydrovatus, and very different from those of Hyphydrus. External marks of the sexes are scarcely to be found, and the colour of the upper surface is without the variegation existing in Hyphydrus. The Pachydri are peculiar to tropical America and the West Indian Islands. I. 21.— Genus DESMOPACHRIA. {Vide p. 340). About twelve species form this aggregate ; they are minute or small insects, of short, broad form, convex beneath. Front of head margined, the clypeus overhang- ing the labrum, but when viewed from beneath the latter is seen to be distinctly exserted. Prosternum extremely minute, forming in fact merely a slender frame for the coxge : prosternal process minute, rhomboidal, acuminate behind. Middle coxae distinctly separated. Metasternum very long in the middle, with its curved side wing excessively slender, so as to be a mere line, the suture between it and the coxa is however excessively obliterated so that this character is not easily appreciated. Hind coxse enormous, their processes quite adpressed to the ventral segment, moderately broad, and leaving quite exposed the coxal cavities : hind border soldered to first ventral segment. Hind legs moderately stout ; their rather stout short tibiae of even thickness throughout. Front and middle tarsi small, fonr- jointed, third joint but little lobed. Elytra on inner face at extremity with a single prominent ligula. TRANS. ROT. DUB. SOC, N.S., VOL. II. 6 H 852 On Aquatic Carnivorous Coleoptera or Dytiscidce. These small insects arc readily distinguished from Pachyhydrus, by the minute prosternal process, by the different shape of the metasternum, (its middle part being more parallel sided owing to the greater development of the hind coxse), and by the less widely separated hind coxal cavities. The species are either unicolorous, or are yellow, with a few thick black marks on the elytra (H. minimus, Wehncke, Hydro- porus dispersus, and H. latissimus, Crotch) ; it is probable however that the latter group will prove to be a distinct genus, somewhat approximating to the Old World Hyphydrus, to which the species are similar not only by their colour, but also by the structure of their front and middle tarsi. External distinctions between the sexes appear to be extremely slight; but I find that in one or two species the prosternal process is of two forms, and this is probably a sexual character. One of the features ot the Dytiscidae, viz., the tendency to reduction in size of the pieces of the presternum is in Desmopachria carried to the most extreme point it has reached in the family. The genus is peculiar to the New "World, but is probably represented by numerous species there. I. 22.— Genus BIDESSUS. {Vide p. 344.) This is a large aggregate comprising fully eighty species. They are insects of small or minute size, the largest attaining only about 3 m.m. of length, they are oblong, or oblong-oval, in form, (a few species however are of broad, short, form, convex beneath) ; with a sort of plica or longitudinal fold or impression on the basal portion ot the thorax, a little nearer to the outside than to the middle, this fold very often is continued on the basal portion of the elytra. Head not, or only indistinctly margined. Presternum small, front coxse very small, prosternal process, moderately long, rather narrow^, and acuminate, its length quite as great as the inter- coxal portion of the jirosternum. Middle coxse nearly contiguous ; when the pro- thorax is taken away, it is seen that the apex of the intercoxal portion of the meta- sternum does not reach to, or connect with, the middle furcate portion of the mesosternum, but a space intervenes between them, and in this space the middle coxae are seen to be absolutely contiguous. Metasternum elongate in middle, excessively short at sides ; hind coxas very large ; posterior cavities not contiguous, but not widely separated, the coxal processes being rather narrow, these are adpressed to the level of the ventral segments, the articular cavities quite unprotected, the coxal lines nearly straight and parallel, shghtly convergent towards the apex; first ventral segment soldered to the hind coxae : hind legs slendei", their tibiae with a slender basal portion, but from the middle to the apex gradually and distinctly thickened : front and middle tarsi 4-jointed, the third joint scarcely bilobed, the fourth joint exserted, quite as long as the third : no tongue on the inner face of elytra near the apex. The genus as here limited seems to extend its variations of structure in the direction of several other aggregates from which however it is really distant. The Un Aquatic Carnivorous Coleoptera or Dytiscidae. 853 species of the widely separated Sternopriscus, for instance, resemble greatly Bi dessi in appearance, and possess similar swimming legs and even the peculiar plicee of the pronotum. The natural arrangement of the species I am unable at present to accomphsh owing to the minute size of the creatures and the consequent fact that they have not been sufficiently collected, so that material for dissection of many of the more peculiar species cannot yet be obtained. It is probable that the aggregate as here defined will prove to consist of more than one distinct primary aggregate or genus. The best indications I can give at present on this point are the following remarks : — Nos. 242 and 243 are distinguished from all others by the fact that their headistruly and evenly margined ; an aproximation to Desmopachria is thus suggested and appears to be supported by some other details. The rest of the species have not the front of the head margined, although many of them have a kind of waved transverse thickening near the front, giving the appearance at first sight of a real margin. Nos. 244, 245, and 246 no doubt form a distinct genus; although I am not able to examine them thoroughly owing to having only a single individual of each. The form approximates to Hydrovatus being very acuminate behind, the size is very minute the head is not margined in front, the coxae and coxal cavities are formed much as in Desmopachria, while the prosternal process, depi-essed in the middle and carinate on each side, is like that of Dytiscus geminus ; hind tibiae as in Bidessus. A comparison with 242 and 243, as well as with Hydroporus granarius, is highly desirable. The thoracic basal impression is smaller than in Bidessus and there is- none on the elytra. Nos. 247 to 254 are insects of short broad form, without pubescence, with the punctures on the undersurface peculiarly large, and the sculpture on the upper surface also coarse, and the plica on the elytra remarkably developed, so that it assumes the form of an elongate carina extending for more than half the length of the wing-cases. It is in these species that the thickening across the front of the head above alluded to is most conspicuous. For one of them (Bidessus maculatus) Babington proposed the generic name Anodocheilus, which may ultimately prove of service, but at present the insect Babington had in view cannot be separated with advantage from the Old World Hydroporus porcatus, Klug, and Hydroporus bicarinatus, Clairv. Nos. 255 to 260, by their posterior coxse, which have a less extension in the longitudinal direction, are separated from the bulk of the aggregate, and by this, and the coarser, more evenly distributed punctuation of their undersurface, as well as by the form of their front and middle tarsi, an approximation is made to some Hydropori; these species however are approached more or less closely by Dytiscus unistriatus and others that I have placed in the same group of the genus. The genus has a large distribution in both hemispheres, 5 R 2 8 54 On Aquatic Carnivorous Coleoptcra or Dytiscidce. I. 23.— Genus HUXELHYDRUS. {Vide p. 369.) Under this name T have separated a species that has in some respects the appear- ance of the members of Bidessus, and likewise is similar to that aggregate in much of its structure, it however departs from them by some very interesting characters; the prosternal process is much more largely developed and elongate, it is flat and only faintly margined at the sides ; the mesosternum is joined to the metasternum at a very obtuse angle ; the hind coxal cavities are more widely separated from one another : the coxal lines are extremely rudimentary, being very fine and short, and visible only in the immediate vicinity of the cavities. To these peculiarities may be added, as of minor importance, that the prothorax is straight at the sides or rather slightly narrowed towards the base, that the undersurface is densely, finely, and evenly punctured, and the elytra are truncate at the apices ; and that the terminal joint of the front and middle tarsi is much more elongate than in any of the Bidessi. Many of the peculiarities of this insect are repeated to a greater or less extent in some of the Bidessi, and in the isolated Sternopriscus, and even in some of the Hydroporini. The Huxelhydrus syntheticus occurs either in Australia or New Zealand, and possibly in each of those regions. I have made this generic name, as well as Tyndallhydrus, Darwinhydrus, and Spencerhydrus, in reference to some men whose clear thinking and able writing have placed us under a load of obligation, my recognition of which I am glad to express. I. 24.— Genus TYNDALLHYDRUS. {Vide ^. 370.) A small species, of which only an unique individual is known to exist, is isolated to form this genus. At first sight one might fancy it to be an ally of Dytiscus duodecimpustulatus ( Hydroporini ), but it is much smaller, and presents the remarkable character of having its prothorax narrowed behind, so that the outline is interrupted as in the Carabida3 : and behind the front coxse the prosternal process is bent upwards, its apex is therefore concealed and is quite separated from the metasternum. The surface is densely punctate, and almost destitute of pubescence : the middle coxae are quite contiguous ; the hind coxae are large, their front border having a great extension in the anterior direction ; the coxal lines are not turned outwards at the tip, and the coxal border is excessively minute ; the coxal cavities are rather widely separated, but a considerable approximation of their trochanters is possible inasmuch as the cavities have a distinct prolongation inwards, between the coxal process and the ventral segment ; the hind legs are slender, and are formed much as in Bidessus. Takinsf all these characters into consideration this little insect would seem to be one of the most anomalous of the Dytiscid:© ; the prosternal process failing to connect On Aquatic Carnivorous Coleoptera or DytLcidcB. 855 with the metasternum is known only in it, in the South American Vatellini, and in the South African Andex. I have not been able to ascertain with certainty that the hind coxse are soldered to the ventral segments, but I believe this to be the case, and if so the genus may take its place in the Bidessini near Bidessus, though very distinct therefrom on account of the structure of the prothorax. This iuterestinsr creature comes from South Africa. I. 25.— Genus A.SDEX. {Vide p. 371.) A. single species is isolated under this name. It is but little known, and its individuals are of peculiar form, the prothorax being greatly narrower than the after- body, and almost narrower behind than in front ; the most remarkable peculiarity of the species is however the fact that the prosternal process does not connect with the metasternum, but terminates in front of the middle coxse, so that these latter can be at once observed to be contiguous : the inter-coxal process of the metasternum does not project between the coxae, and is thus widely separated from attaining the mesosternal fork. The front and middle legs are elongate, and the fourth joint of tlieir tarsi is elongate and slender, the third joint being rather small and but little emarginate ; the swimming legs are rather slender and elongate. The head is rounded in front, but not margined. The Cape of Good Hope is the territory of this creature. The Vatellini, and the genus Tjaidallhydrus of the Bidessini are the only Dytiscidse besides Andex that possess a prosternal process not reaching the metasternum. The Vatellini are exclusively South American insects, but Tyndallhydrus like Andex is a native of Southern Africa. 1. 26.— Genus HYDROPEPLUS. (Vide p. 372.) This is another autogenus ; the individuals of this unique species have much the form and size of Hyphydri, but the surface both above and below is very densely and finely punctured. The front of the head is evenly rounded but without raised margin. The prosternal process is small, but somewhat elongate, it is very acuminate, its apex is somewhat bent downwards and rests against the short and inconspicuous inter-coxal process of the metasternum ; the extremity of this latter process is a little curved upwards to meet the prosternal process, but it does not connect with the mesosternal fork. The hind coxse are very largely developed, being very elongate with very arched anterior border, the wing of the metasternum deflexed outside this border forms a very slender parallel-sided band. The hind coxal cavities are quite exposed ; the swimming legs are elongate and slender, their tarsi ai-e longer than the tibise, and the tibial spurs are shorter than the first 856 On Aquatic Carnivorous Coleoptera or Dytiscidce. joint of the tarsus. The front and middle tarsi have their third joint short and broad not bilobed, but with the outer portion of its upper surface excavate or channelled for the reception of the base of the terminal joint : this latter is very elongate, two or three times as long as the third joint. The epipleura has at the shoulder a well marked genicular fossa, limited behind by a distinct raised line. This, like the allies, is an inhabitant of South Africa. I. 27.— Genus PRIMOSPES. {Vide p. 372.) This is at present an autogenus. The insect has much the size of a large Hydropoius and is similar thereto in form. The surface above and below is densely and finely punctate, and the sculpture on the anterior parts of the upper surface becomes obsolete. The head is rather truncate in front. The epipleura; of the elytra possess at the shoulder an indefinite genicular fossa not limited behind by a definite raised line : the swimming legs are quite slender. In other respects the characters are those of Hydropeplus. This species is from Capetown. I. 28.— Genus CCELHYDRVS. {Vide p. 373.) This is again as yet an autogenus : it consists of a species whose individuals have about the size of the Coelambi, and are of short peculiar form, suggesting themselves as an intermediate between the Coelambi and Hyphydri. The head is subtruncate in the middle in front, and not in the least margined ; the prosternal process is rather short and very acuminate, its apex is decurved, and in repose just rests on the extremity of the very short and slender inter-coxal process of the metasternum; this is a little curved towards the mesosternal fork, which, however, it does not attain, and it is obscurely grooved in front. The hind coxae are very large, and their cavities are rather broadly separated, and quite exposed, the coxal processes being adpressed, and without any trace of external acute angle. The swimming legs are rather short, and are moderately stout, the upper third of their tibia;, being a good deal more slender than the apical portion, the spurs are not straight but distinctly slightly crooked or sinuate. The front and middle tarsi have the third Joint rather small ; the terminal joint is likewise not greatly developed, it is however exsertcd, and as long as the third joint. The epipleura has a definite genicular fossa at the shoulder. This insect is likewise an inhabitant of Southern Africa. On Aquatic Carnivorous Coleoptera or Dytiscidce. 857 I. 29.— Genus DARWINHYDRUS. {Vide p. 373.) This name represents an autogenus, known only by a single individual ; it is an insect of small size, of peculiar broad rounded form, with a rather flat upper surface and costate elytra. The head is rounded and margined in front; the swimming legs are slender and rather short ; the epipleurae of the elytra become gradually narrower from the base to the apex ; by this character it departs from the other Hyphydrini, and approximates to Hydroporus nebulosus, &c. (gen. Chostonectes) of Australia. This insect was recorded in Castlenau's collection as being from Capetown ; I consider however there is just a possibility it may really be from Australia. I. 30.— Genus HYPIIYDRJJS. {Vide p. 374.) About five-and-twenty species at present form this aggregate. The size of the individuals is rather uniform, varying between 31 and 6 m.m. of length ; the form is short, broad, and very elevated, the convexity being chiefly on the undersurface. The upper surface is nearly always variegate in colour, by means of black marks on a yellowish or brownish ground. Head rounded in front and margined, labrum not visible from above, exserted and visible from beneath. Prosternal process short, not truncate behind, somewhat variable in size and form, its apex not received into a groove on the inter-coxal portion of the metasternum : middle coxae nearly contiguous ; the inter-coxal process of the metasternum is curved upwards at its termination to touch the process of themesosternum, and this perpendicular poi'tion is slightly hollowed in adaptation to the back (or upper) part of the prosternal process. Metasternum elongate in the middle, with excessively short side wings which are greatly deflexed down the outer portion of the hind coxas. Hind coxse enormous, their anterior border excessively arched ; coxal processes adpressed, their outer terminal angle obtuse or rounded ; the articular cavities, are therefore quite distinctly separated and are not at all protected, but (on the leg being extracted from the articulation) are seen to be entirely exposed externally to the coxal process : first ventral segment not soldered to coxae. Elytra on their inner face near the apex of their raised ledge with a highly developed elongate tongue, which is received into a pocket on the internal face of the lateral piece of the penultimate segment. Swimming legs rather slender ; their tibiae and tarsi rather strongly ciliate, the latter on both upper and under edge ; terminated by a rather stout, little curved claw, and with an excessively short and indistinct second claw. Front and middle tarsi four-jointed, the fourth joint short, protruding but little from the groove at the apex of the third joint in which it is inserted, the third joint large, the fourth inserted at a great distance from its base. The sexual differences are often very striking, the females being often smaller and weaker with quite different sculpture : as regards this latter point the females are dimorphic in some species, certain individuals resembling the males : the 856 Un Aquatic Carnivorous Culeoptera ur DyttscidcB. swiiuiiiing legs of the male are more powerful, as are also often all the other legs ; the front and middle tarsi are frequently dilated ; these tarsi are also often compressed laterally and rarely are quite flat on the upper surface : the anterior trochanters in the male are frequently the seat of incomprehensible secondary sexual characters, in aoiue species scarcely to be detected, while in others they ai'e carried to an extent that may almost be called ludicrous. The peculiar structure of the front tarsi readily leads to any water-beetle possessing it being identified as a member of this aggregate. In no other DytiscidaB is the terminal joint of the front tarsus so little exserted from the third joint ; this is so remarkable that in the females of some species of the genus the tarsi have the appearance of being only three-jointed. The dark marks on the elytra are formed by lines placed in the longitudinal direction, but of irregular lengths, and much united together in the transverse direction so as to give somewhat the appearance of highly irregular transverse bands ; the marks so formed rarely extend so far as the outer margin which is thus nearly always paler than the sutural portions. The genus is in several respects approximated by Hyphoporus of the Hydroporini. Hyphydrus is distributed over the whole of the Eastern hemisphere, except the colder parts thereof ; in the Western hemisphere it has only been found in New Caledonia. I. 31.— Genus STERNOPRISCUS. {Vide p. 384.) Ten species form this aggregate ; their individuals are of small size, and of moderately elongate form ; the punctuation of the upper and under surfaces is very dense, and the colour more or less variegate. The sexual differences are often extreme. The thorax has a longitudinal plica on each side. The prosternal process is elongate and slender ; the middle cox« are absolutely contiguous, and their exserted apices project beyond the level of the body ; the fork of the mesosternum is elongate, and the prosternal process which extends over the middle coxse is thus rendered peculiarly protuberant. The hind coxse are elongate externally. The hind coxal cavities are not contiguous, but each has an internal prolongation, by means of which the basal portions of the two swimming legs are allowed Yevy nearly to meet. The coxal lines are short, but rather acutely elevated, distinctly turned outwards near the apex, forming a rather acute coxal process, with a small coxal border. The swimming legs are slender, their tibise are slender at the base, and near the base have a crook or distortion, which is more conspicuous in the males than in the females. The front and middle tarsi are distinctly five-jointed : the mesosternum is placed at a very obtuse angle with the metasternum and thus is quite visible. The genus is very easily distinguished by the distinctly 5-jointed tarsi, and the comparativelv ill-constructed and fitted together parts of the mesosternum and adjacent pieces. It has points of similarity with widely separated forms, and has On Aquatic Carnivorous Coleoptera or Dytiscidce. 859 no near allies, and is an exemplification of the peculiar isolation so frequently found to exist in tlie case of these so-called synthetic types. In general appearance and in the structure of the mesosternal parts, Huxelhydrus of the Bidessini makes a quite incontrovertible approach to Sternopriscus ; while from another direction Necterosoma of the Hydroporini approximates it by the 5-jointed tarsi ; and even Dytiscus dorsalis in Hydroporus makes some approach to it, in the mesosternal structure and some other points. Sternopriscus is peculiar to Australia ; and it may here be mentioned that Huxelhydrus and Necterosoma just alluded to are also exclusively Australian ; we are, in my opinion, not justified from these facts in inferring a genetic connection between these forms, but I think we are quite justified in concluding that the conditions of existence of certain Hydroporini in Australia have induced the development of similar structures in perfectly distinct creatures. The similarity of structure is evidence not of descent from a common ancestor, but of conformity of the conditions of existence at certain periods of the ancestral records. The classification of Sternopriscus is very difficult, for although it is clear that it is correctly placed amongst the Hydroporides, it does not appear possible to locate it satisfactorily in any of the four secondary aggregates which form that group ; if we take the aggregate of its characters it would appear to be nearest to Huxelhydrus in the Bidessini, but it does not possess the soldered coxse and ventral segments, which is the essential character of that group. On the other hand there is no member of the Hydroporini to which it approaches Avith any nearness, and I have decided that it is the more natural course to le&^e it at present isolated during the second synthesis, and to unite it with other components to form the Hydroporides of the third synthesis. I. 32.— Genus IIYPHOPORUS. [Vide p. 390.) Three species form this aggregate, their individuals have the same appearance as- the species of Hyphydrus, to which they are similar in size, form, and colour : and the similarity of structure of the front tarsi, in combination with these slighter characters, indicates an undoubted approximation between the two genera ; the third joint of the front tarsus is large, and little emarginate, and the terminal I'oint short and little exserted. The front of the head is rounded and margined. The elytra have on the shoulder of the epipleura a definite genicular fossa, which is limited externally by a raised line, and the ligula on the inner face of the elytra is highly developed ; the epipleura3 are very slender in their posterior portion ; the articular cavities of the hind coxse are slightly but quite distinctly separated, and the extremity of the upper covers of the cavities is distinctly displayed beyond the apices of the coxal processes ; the coxal lines are distinctly sinuate or turned outwards near their apex, and there is a short, rather broad, coxal border. The genus as above stated approximates to Hyphydrus, but its closest ally is TEANS ROT. DUB, SOC., N.S., VOL. II. ^ 860 Oh Aquatic Carnivorous Coleoptera or Dytiscidce. Ccelambus, from which it differs by the terminal joints of the front tarsi, and by the gi-eater separation of the articulations of the swimming legs. The species are found in the East, in India, and Egypt. The genus is not a very natural or satisfactory one, as Hydroporus solieri is not so Hyphydroid as its allies ; there can be little doubt that other allied species remain to be discovered, and the separation of the species into two distinct aggregates would be at present premature. I. 33.— Genus PAROSTER. {Vide j). 391.) Three species from Australia form this aggregate ; the individuals resemble greatly ordinary Hydropori, but have the upper surface more convex transversely than is usual in the species of the genus Hydroporus : the size is rather small, (3 or 4 m.m. of length) the form convex, rather short, but not very broad ; the surface is without pubescence. The head is not in the least margined in front ; the prosternal process is compressed laterally, strongly carinate, and elevate along the middle ; the mesosternum does not connect with the inter-coxal process of the metasternum ; the hind coxae have a moderate extension in the anterior direction ; their processes are peculiar, the intra-rimal portion being prolonged considerably beyond the extra-rimal portion ; the coxal lines are effaced in their posterior part, the coxal border is excessively minute with slender, acute, outer angle, and the articular cavities are much exposed ; the structure of these parts may be briefly described by saying, that the articular cavities are rather widely separa,ted, and that there exists a quite distinct, indeed rather large coxal notch, notwithstanding the small size of the terminal portions of the coxal processes. The hind legs are slender, their tibiaa are slender as well as a little crooked below the knee ; the genicular area of the wing-case is bordered behind by a raised line ; the inner face of the wing-case is without any trace of apical ligula : the basal ventral segment is not soldered to the coxje. The species are peculiar to Australia and are very rare in collections at present. These obscure and unattractive insects prove to be of considerable interest when examined and compared, and to be much isolated : they have resemblances to Bidessus (of the Bidessini), as well as to Ccelambus of the Hydroporini ; the approximation to Bidessus consists in the form of the articular poi'tions of the hind coxae, which may be described as that which exists in Bidessus but rendered more conspicuous by the wider separation of the articular cavities : the slender hind tibiae also are such as exist in Bidessus. The genus differs from Ccelambus by the peculiarities of the coxal processes, and by the want of ligula on the inner face of the wing-case. _ On Aquatic Carnivorous Coleoptera or DytiscidcB. 861 T. 34.— Genus HEROPHYDRUS. {Vide p. 392.) Six species form this aggregate ; the individuals are of large size (comparatively with many other Hydroporides), from 4 to 6 m.m. of length : they are oblong- oval in form, very convex beneath ; without pubescence, coarsely punctate ; the head is either margined in front, Avith the margin interi'upted in the middle, or is without margin ; the fourth joint of the front tarsus is but little elongate in com- parison with the others, which are narrow in proportion to their length, the third joint only obscurely bilobed, and the insertion of the iourth joint is nearer to the apical than to the basal edge of the third joint ; the front tibise are short, and rather broad ; the ridge on the inner face of the elytra is largely developed, risino- gradually from the front towards the extremity till its greatest prominence is attained, and then falling abruptly, so that as regards one of its sides (the posterior) it forms a ligula, but as regards the other does not : the genicular area of the epipleurae is limited externally by a well-marked line ; the hind legs are slender ; their coxae formed as in Ccelambus. The genus is nearly allied to Ccelambus, but differs b}'- the elytral ridge, as well as by the shorter, and comparatively broad, front tibias ; the shape of the tibite suggests an approximation to Hydrovatus, which is confirmed by the rather small front tarsi, as well as by the swimming legs, slender and ill-developed in proportion to the weight and size of the insect. Madagascar is the metropolis of the aggregate, three species being peculiar to that island, while the other three are found in neighbouring regions, — two in South Africa, these two the most Ccelambus like — ; while the sixth species has an exten- sive range, being found in Arabia, Senegal, Egypt and North Africa, and Southern Europe. I. 35.— Genus CCELAMBUS. {Vide p. 394.) This is an extensive aggregate, consisting of about fifty species ; the individuals are convex beneath, but in other respects somewhat variable in form, usually oblong-oval, but sometimes shorter, even rotund in form ; they are nearly or entirely destitute of pubescence, the upper surface is usually pale, with distinct black marks, the under surface nearly always with coarse, (or moderately coarse) punctuation. There is always a distinct, and abrupt ligula on the inner face of the elytra, and the genicular area of the epipleura is well defined, and generally limited externally by a more or less raised line : the epipleurse are greatly reduced in breadth in their posterior portion, in fact opposite the hind margin of the second ventral segment there exists nothing of the epipleura but its two marginal lines, which have become contiguous. The front border of the hind coxae has much extension in the anterior direction, (especially in the elongate species constituting the greater part of the genus), and the culmen or summit of its arch is narrow, and in extreme cases est 862 On Aquatic Carnivorous Coleoptera or Dytiscidce. (Dytiscus parallelogrammus) almost angular ; in such species the metasternura is elongate in the middle, and although its wing is much abbreviated as its outer portion is reached, yet it remains comparatively broad till the culmen of the coxae is reached, and there is very abruptly deflexed outside of it as a veiy slender band. Altliouo'h the species of this aggregate show much diffei-ence in various points of structure, yet they are constant in the possession of the elytral ligula, and the genus is thus absolutel}' distinguished from Deronectes. Although the head differs much in the extreme forms, yet as it is not exactly alike in any two species it does not justify the formation of two (or more) distinct aggregates; in the shorter species the head is completelj^ rounded in front, and bordered with a distinct raised margin, and the labrum is placed so much on the undersurface as to be greatly concealed, — the head in such species closely approaches that of Hyphydrus. In other cases however the labrum is brought forward to the front of the head, and quite exposed (Hydroj)orus enneagrammus, No. 419, Dytiscus confluens, No. 423, &c.) the front of the head being truncate-emarginate ; various species ai'e more or less intermediate between these extremes. In the development of the hind coxae there exists also considerable difference between the extreme forms. The species of short form possess hind coxa3 with their antero-external portions less extended towards the front of the body, so that the shape of the culmen of the coxal arch is more rounded and less abrupt and angular than it is in the more elongate species. In other of the structural points characteristic of the genus, numerous shades of variation may be detected ; such is the case with the form of the tarsi, and the development of the genicular area of the epipleura. In all the species the epipleura is small, and is much reduced in its posterior portion : Hydroporus enneagrammus shows us the extreme of this reduction : in this species the epipleura at the base is very small, and before the middle length of the wing-case is reached has altogether disappeared : this diminution of area is accompanied by some alteration in the form of the shoulder of the wing-case, and as a result of this it seems at first sight as if the genicular area were altogether absent, nevertheless on a more careful examination not only is the area seen to be definitely present, but also the existence of a line marking it oflF externally is certified ; in agreement with this reduction of the epipleura, the ligula of the elytra is also extremely minute in this species, but yet it exhibits the form characteristic of the other species ; in this peculiar insect there cannot be detected on the undersurface of the body any trace of the coarse punctuation that exists (though in certain species only in a comparatively slight degree) in all the other components of the aggregate. The external sexual disparities are, as a rule, not strongly marked : scarcely to be detected in Dytiscus insequalis (No. 381), they become so far as regards the legs On Aquatic Carnivorous Coleoptera or Dytiscidce. 863 considerable in Hydroporus polonicus (No. 406) ; while in certain species (e.g., Dytiscus ijarallelogrammus (No. 416), Dytiscus imjiressopunctatus (No. 409), the females are dimorphic, one of the forms, and that the rarer, departing greatly in sculp- ture from the males, and ordinary females. The most remarkable of the sexual disparities is that where the males have the ventral segments of a black colour, while they are yellow in the females (Hydroporus flaviventris, No. 420, and H. pallidulus, No. 422). In H. enneagrammus the colour of the ventral segments in the females appears to be variable, sometimes nearly yellow, it is in other individuals quite black except at the tip. The species are confined to the northern hemisphere, and scarcely exist in its tropical zone ; several appear to be fond of brackish or even salt water, and it is probable that when the large fresh-water lakes, and salt lakes of America and central Asia are well examined, a considerable increase in the known species of the genus will result. I. 36.— Genus CHOSTONECTES. {Vide p. 408.) Four species compose this aggregate ; they are insects of broad, more or less short outline, convex beneath : the upper surface is pubescent, the undersurface bears coarse punctuation specially remarkable on the coxae. The head is rounded in front, but not margined ; thorax with its greatest width behind ; all the legs are rather slender, and the posterior femora are slender, especially in their outer portion ; the hind coxte have only a moderate extension ; the outer apices of the coxal processes are acute ; the elytra have a very distinct, strongly raised internal ridge, but no ligula ; the genicular area of the epipleura is abruptly limited externally, but not by a raised line, though at first sight such a line appears to exist, owing to the abrupt cessation of the coarse punctuation of the epipleura. The hind tibise are glabrous externally, possessing only a single series of punctures. The four species associated in this aggregate are not by any means closely related hiter se ; and may indeed prove to be incorrectly placed as one genus. The general form is that of Dytiscus inaequalis (Coelambus) or Dytiscus ovatus (Hyphydrus), and the shape of the head and eyes especially suggest such likeness : Chostonectes sharpi is nearest in form to D. insequalis, Hydroporus gigas being more similar to Hyphydrus. The genus is approached by Hydroporus latus of the genus Deronectes in more than one point of structure, but these Australian insects have a different form from it, a coarse punctuation, glabrous posterior tibise, a well marked hum.eral area to the elytra, and acute external apices to the coxal processes ; moreover the terminal half of the epipleura is larger. The species are peculiar to Australia and Tasmania. 864 On Aquatic Carnivorous Coleoptera or Dytiscidm. I. 37.— Genus ANTIPORUS. {Vide p. 410.) Eight species form this aggregate ; the individuals are in colour a mixture of black and yellow, in a rather indefinite and variable manner : the form is oblong- oval, moderately convex beneath, the surface is densely and evenly punctured both on the upper and under sides, and is not shining, and bears an excessively minute, scarcely visible pubescence. The eyes are convex and prominent ; the portion of the head in front of them is very short, its front edge is variable in form but does not possess a raised margin. The anterior tibiae are slendei% and their tarsi usually have the joints elongate, and narrow at the base, the third being deeply bilobed, the real fourth joint not visible, the terminal (apparent fourth) joint elongate, and inserted near the base of the third joint. The posterior portion of the epipleura is rather broad, there is no definite genicular area, the epipleura being punctured up to the point where it becomes contiguous with the prothorax : on the inner face of the wing-case there exists a well-marked ridge ; this is not developed into any distinct ligula near the apex, although there is a short, more or less distinct prominence on the ridge at the point where the ligula exists in some other genera. The hind cox« have a very considerable anterior extension (as in most species of Coelambus, e.g., Dytiscus parallelogrammus, No. 416). The terminal portions of the coxal lines are parallel, not turned outwards ; the hind legs are slender and their tibiae are punctate externally. The external sexual disparities are nearly confined to the legs, the males are usually in this respect remarkable. The species of this aggregate in form and sculpture, and even in colour, approxi- mate to the Deronecti of Europe, and, as in that genus, the wing-cases are frequently denticulate at the tip ; the broader hind portion of the epipleura separates the aggregate from most of those near it, but approximates it to Chostonectes, from which it differs by the shape of the front tarsi, which have always an elongate terminal joint, as well as by numerous minor characters, amongst which the fine dense sculpture of the under surface is conspicuous. These insects are found only in Australia, Tasmania, and New Zealand : the species from the latter locality are very closely allied to Australian species, and it is possible they may be Z'ecent immigrants to New Zealand and not really distinct species. I. ^Q.—Genn& NECTEROSOMA. {Vide ^. 413.) This is an aggregate consisting of eight species ; in many respects the individuals are similar to those of Antijjorus, but they differ in some important points, and one of these — the structure of the anterior tarsi — distinguishes the aggregate from all its near allies; all the five joints are distinctly visible ; the third joint is not truly bilobed, but only emarginate at its outer portion, and the small fourth joint pro- jects quite distinctly beyond it, and is therefore conspicuous between the third and On Aquatic Carnivorous Coleoptera or Dytiscidce. 865 fifth joints. The coxal Hnes have their terminal portions much turned outwards, and in their anterior parts are much less widely separated from one another than they are in Antiporus. The ligula on the inner face of the elytra is quite distinct although short and broad. The characters in other respects are much those of Antiporus. The genus is peculiar to Australia and Tasmania. I. 39.— Genus MACROPORUS. {Vide p. 416.) This is an aggregate consisting of six species ; the individuals are of large size amongst their allies, the largest attaining 7 m.m. of length, but vary much in width, they are convex beneath ; the upper surface is distinctly pubescent, the lower is coarsely punctured : the size attained is greater than in any other Hydroporini, and equals that of the members of the Hyphydrini. The hind coxse have a large area, and are elongate even quite near the middle longitudinally of the body, their anterior border does not stretch abruptly forwards, so that the length of the coxa at its longest part is not twice what it is at its shortest pan ; the coxal lines are subparallel, being a little divergent both in their anterior and posterior portions ; and their articular cavities are but slightly separated ; the femora are broad and sublaminate (showing when viewed from above a distinct lamina at their outer hinder portion, which when the tibia is flexed receives and covers its base : the hind tibiae are glabrous externally, with a series of setigerous punctures near the margin : the epipleura of the wing-case is moderately broad in its terminal portion, and is impressed at the humeral angle, but there is no trace of any raised line limiting externally this area : there is no ligula on the inner face of the wing-case : the real fourth joint of the front tarsus cannot be perceived. The genus is especially characterized amongst the Hydroporini by the well developed swimming legs, these organs attaining in Macroporus a perfection greater than in any other Hydroporini. In some other respects there is considerable variety amongst the species ; M. lateralis, has the terminal joint of the front tarsus quite short, and in fact approximates to Hyphydrus by the structure of this part, while the other species have the joint alluded to either considerably or greatly more elongate. The species are found only in Australia and Tasmania. I. iO.— Genus DERONECTES. (FiJe p. 418.) Group 1. The characters assigned to the first group of species of Deronectus (see p. 419), justify the association together of about twelve species, which when carefully examined exhibit nevertheless important structural differences amongst themselves : 866 On Aquatic Carnivorous Coleoptera or Dytiscidce. the prothorax may be remarkably narrowed behind and so leave the shoulders of the elytra quite free (D. longipes, &c.), or its base may be of equal width with the base of the elytra (Hydroporus platynotus, No. 459), or even slightly broader than the elytra (H. semirufus, No. 458) ; in some species there is considerable difference between the sexes in this respect (Hydrop. lareynei, No. 454, and H. opatrinus, No. 455), which fact has led to the sexes in such cases being considered as distinct species, even by skilled coleopterists. Where such sexual difference exists, it is always the case that the female has the base of the thorax narrower than the male. The coxal lines show very important difterences in the group ; thus in Hydroporus latus (No. 461), they are very approximate and quite parallel till near the extremity, when they gradually diverge ; in H. opatrinus (No, 455) they are very different from this, for in front they are widely separated, and then converge till the extremity is reached and here their terminal portion is abruptly turned outwards. In H. opatrinus the articular cavities of the swimming legs are distinctly separated, the portion intervening between the two, projecting backwards so as to be very visible, while in H. latus the two cavities are contiguous, except that they are separated by a thin lamina, which does not project beyond tliem, and can only be seen by looking along the plane of the ventral segments. Also the prosternal process shows a good deal of variation in the group : in H. bombycinus it is shorter than in the other species, and its terminal portion is considerably decurved or bent downwards; in H. latus also it is short, but there is.no trace of decurvation of the apical portion ; in H. opatrinus and H. moestus it is more elongate, and its lateral compression reaches its maximum. The sculpture of the upper surface in this group is peculiar ; it consists of a fine dense nearly evenly distributed punctuation, and in addition to this a coarser and more unevenly distributed punctuation ; in the species with the thorax narrowed behind the coarse punctuation is but little developed, but in other species such as H. opatrinus (No. 455), and H. bicostatus, (No. 460), it becomes so extensive as to overpower or mask the fine punctuation. The undersurface also is covered with a dense, fine sculpture, evenly distributed over the middle and hind bodies, and in addition there may be present on the hind coxfe a few coarse but subobsolete punctui-es. Deronectes longipes may be considered the lowest form of the group, and H. latus the highest. Were it not for the existence of the last named species the group would be much more isolated than it actually is ; for the separation of the hind articular cavities would then be a character constant in the whole of the group ; this separation of the articular cavities exists however in the following group ; and on the other hand H. latus of the present group departs from its allies in this respect, to resemble the species of the fourth group ; so that this character does not justify the establishment of a distinct genus. On Aquatic Carnivorous Coleopteva or Dytiscidce. 867 Group 2. Two closely allied species form the second group of Deronectes ; the form of the body is peculiar; the elytra have their terminal portion more prolonged and acuminate, and the last ventral sefrment is more elono-ate than in the members of the following group. The other characters of the group have been given on p. 419, and it is only necessary here to remark that as the first group of the genus agrees with this second group in the separation of the hind articular cavities ; and as H. tessellatus, (the third group), has the posterior tibise punctured in a similar manner, it is clear that these characters do not justify the establishment of a distinct genus for the second group : I expect however that characters will ultimately be detected that will call for its separation as a good and distinct aggregate. Group 3. This group consists of an isolated species, with coarsely punctate hind tibiae, but in other respects similar to the following or fourth group ; it would thus seem to be a connecting link between the first and fourth groups, but such is not really the case, and it is more correctly an insect belonging to the fourth group but possessing to a considerable extent one of the more important characters of the first group. It is to be noted that this exceptional species is an insular one, found in the Canary Islands, and it is additionally intei-esting to find that the H. vigllans of Madeira which I have placed in the following groups, has some punctures placed on the basal portion of the tibia and so forms a connecting link between the H. tessellatus and the fourth group. Group 4. The fourth group of Deronectes comprises the majority of the genus, and includes all the species having the infero-external face of the hind tibiae glabrous and shining. The group is specially well represented in the regions near the Mediterranean, but includes a very widely distributed alpine and boreal species, and one or two from the New World. About fifty species, arranged in four groups as above expressed, form the aggregate Deronectes. The form of the individuals is oval, or oblong oval, and only moderately convex beneath, the upper surface is very finely pubescent, and finely punctate. (In most of the species, the punctuation is very fine, and the undersurface is entirely without coarse punctures, but has an extremely dense, fine, somewhat rugose sculpture, rendering it very opaque, and the upper surface is more or less variegate in colour ; the remarkable first group forms however an exception in these respects, for the surface is not variegate, and a coarse punctuation exists, to a greater or less extent, in combination with the fine sculpture). The head is never margined in front, the epipleurse of the elytra are much narrowed TBAHS. SOT. DUB. SOC, N.3., VOL. II. * T 868 On Aquatic Carnivorous Coleoptera or Dytiscidce. (in the length between the hind margin of the posterior coxpe, and the second ventral segment), so that their terminal portion is very narrow, although in some species it remains quite di?tinguishable till as far, at least, as the commencement of the last ventral segment, (Dytiscus depressus, No. 472, &c.) ; while in others it cannot be distinguished after the second ventral segment is passed (D. griseostriatus, No. 493, &c.); the difference between these two forms is however not great, and intermediates occur. There is no ligula on the inner face of the elytra near the apex ; the genicular area of the epipleura is generally indistinct, and is never limited externally by a raised line ; the swimming legs are but slender, their femora are never incrassate, and their postero-external angle is never acute. The hind coxee are not large, their front border having but litt'e extension in the anterior direction, and the culmen of its arch is rather rounded and broad, thus contrasting with Coelambus : the hind articular cavitie.s are contiguous or nearly so. The species are found in the European and Mediterranean regions, but one or two exist in Nortli India and Abyssinia and Arabia, and one or two others in the northern portion of the New World. I. 41.— Genus HYDROPORIJS. {Vide p. 435.) Group 1. The first group of species included in Hydroporus consists of certain insects dis- playing a slight peculiarity in the structure of the apices of the coxal processes ; the middle portion of the apex being slightly prolonged, so that the articular cavities are distinctly separated by this middle portion ; which is closely adpressed to the plane of the ventral segments. Six species are included in the group ; they all have the third joint of the front tarsi strongly bilobed, and the general characteristics are much those of the following group ; the punctuation of the under SLU'face is sometimes but little developed, and never very coarse, the wing-cases are •. ariegate in colour, and the undersurface is never black, though sometimes greatly in'"useate The species are all rare, and have therefore been but imperfectly examined ; one of them, (Hydroporus vittatipennis, No. 500), is perhaps not very naturally associated with the other species, for the lateral margin of its prothorax is extremely slender, even in front, while in all the other species it is more or less flattened and. thickened in front. Group 2. In this group the front tarsi have the third joint more deeply bilobed than is the case in the following group ; (in some species however the distinction is but slight in this respect, see Hydroporus dimidiatus, No. 517) ; the thoracic side margin is usually thickened and flattened in front, but to this also there are exceptions (see H. mellitus, No. 502, and H. hybridus. No. 519). The wing-cases are variegate but occasionally ():'ly obscurely so; the undersurface is red or yellow; the metasternum On Aquatic Carnivorous Coleoptera or DytiscidcE. 8(J9 is sulcate in front; the coxal processes have their middle part projecting- quite as far as, or a little farther than their outer terminations or angles, but only in a few species can the cavities be detected to be at all separated, (see H. clypealis, No. 508) ; the punctuation of the undersurface is coarse and extensive. Some of the species depart slightly Irom the others in the structure of the coxal cavities, to approximate in this respect to the first group. And in B. dimidiatus the sculpture of the undersurface may be looked on as intermediate between this group and the third group ; the species just named also approximates the third group by the structure of its tarsi. Both in this and the preceding group the coxal lines are usually remarkably sub-parallel, strongly elevated, but little separated in their anterior portions, and very little divergent at their termination ; but these characters are not absolutely constant, for H. hybridus, Aube (No. 519), has the lines rather widely distant in front, and rather abruptly approximated about the middle of their course; also in it, and still more in H. dimidiatus, they show an undoubted, though never conspicuous, divergence in their terminal portions. In the two groups the apices of the processes never assume, even in an incomplete manner, the form of rounded lobes, but are truncate, or approximating thereto, and their outer angles are nearly acuminate. Group 3. This group includes about thirty species, of variable form and size, but all have the upper surface variegate ; the hind coxal cavities are quite approximate or very nearly so, and the coxal processes do not on the mesial line e.Ktend quite so far back as at their outer portion, and so do not present a common straight hind margin, but assume more or less decidedly the form of separated lobes. The species are distinguished from those of all the other groups of Hydroporus (except group 9) by the rounded form of the coxal processes ; those arranged at the commencement of the group show this character only in a slight degree, and resemble the species oi the fourth group of Deronectes : also the earlier species have the third joint of the front tarsus but little lobed, while the terminal one is more elongate than in the species towards the end of the group. Group 4. This group includes about eighty species ; in it the hind coxal cavities are quite approximate and the lamina dividing them quite concealed ; the coxal processes are soldered together quite to the hind margin, so as to present a common, truncate extremity ; and their outer angle formed by the short coxal border is only very slightly rounded or obtuse ; if the common suture at the hind margin is a little more prolonged backwards, yet it is only very slightly so, and the projecting portion is not at all adpressed to the level of the ventral segments. The prothorax is with- out any longitudinal stria or depression at the side. 6 T 2 870 ■ On Aquatic Carnivorous Coleoptera or Dytiscidce. The group is a very natural one formed by closely allied species, in no one of ■which have I been able to detect any important structural distinction from the others. The chief variations of structure are to be found as follows : 1st, in the prosternal process, which in H. modestus and the species iicar it is more elongate than usual ; and is also either much compressed laterally, and so appearing narrow — the case in most of the species of the group — or is little compressed and broad, as in H. arcticus ; 2nd, in the third joint of the front and middle tarsi, which is either comparatively large with xerj elongate sub-lobes (Dytiscus modestus, No. 627), or is small and obscurely lobed, (Hyphydrus pubescens. No. 568, &c.) ; and 3rd, in the amount of extension forwards of the front border of the hind coxsa ; this is very slight indeed in some species {e. g., Hyphydrus memnonius, No. 558 and Hydroporus sibiricus, No. 583), so that the coxa is no longer externally than it is along the mesial line, and the culmen of the arch is very broad and low ; in other species the anterior extension may be a little greater (f the fourth ventral side piece is about six times its breadth, while in Scutopterus On Aquatic Carnivorous Coleoptera or Dytiscidce. 890 horni this piece is only about 2j times as long as broad. In many other respects however the genus undoubtedly comes near Meladema. The prothora,x is without side margin ; the prosternal process is rather broad, distinctly compressed ; the metasternal groove is imperfectly developed ; the wings of the metasternum are not large, (in Scutopterus horni they are decidedly small) ; the coxal lobes have a considerable extension in the transverse, but little in the longitudinal direction. The swimming legs are rather slender especially the tarsi, and the lamina of the femora is rounded at its outer angle; the terminal joint of their tarsi is elongate, longer than the preceding one, and their lower claw is very long, t\Yice as long as the other. The species of this interesting and isolated genus are peculiar to the northern parts of North America, and are still rare in collections. I. 62.— Genus RHANTUS. {Vide p. 607.) This is an extensive aggregate, with forty species : the size of the individuals is moderate (from 8 to 15 m.m. of length). The side pieces of the fourth and following- ventral segments are very narrow ; the metasternal groove is distinct and Avell- defined, and the terminal joint of the hind tarsus is not longer, (or is but little longer) than the preceding one. The numerous species are distinguished constantly from their allies by the above characters, as well as by two others, which are not quite so constant, these are first that the prothorax has a distinct lateral margin, Nos. 957, 958, and 959 being however exceptions in this respect ; and second, that the swimming legs are rather well developed, the femora having their undersurface forming a developed lamina towards the extremity. The colouration of the upper surface usually is yellow, with black specks on the wing cases, but in some species it is entirely black, and in other cases nearly so ; where the wing cases are nearly but not quite entirely black it is generally the margins that are pale, and the black colour seems to have been produced by a coalescence of the black specks. The prosternal process is moderate in length, never elongate, nor very short, and neither slender nor broad, always distinctly compressed. The metasternal groove though not elongate is perfectly well developed, the middle coxse never being so much approximated as to interfere with its development, and it has therefore always perfectly distinct sides ; the coxal lobes are broad and the division between them extends far forwards (except in Colymbetes capensis (No. 957) and Rhantus goudoti (No. 958), which depart from the other species in this respect ; the supra articular border is narrow ; the coxal lines are much separated in front ; the side wings of the metasternum are variable in size, but are never very small. The swimming legs are well developed in some species such as Rhantus goudoti (No. 958), and Dytiscus calidus (No. 942), but are more slender in others, especially in Colymbetes pacificus and other species placed near the TRANS. ROY. DUB. SOC, K.S., VOL. II. 5 Z 900 On Aquatic C. 931 tropical South America, tlie Pacific Islands (including New Caledonia) or the Malayan and tropical Asiatic regions. The one or two species found in New Zea- land are very closely allied to Australian species. Australia (with Tasmania) possesses five genera (containing about thirty species) peculiar to itself, but the great majority of the species are found in the North American and European regions, where the three genera Ccelambus, Deronectes, and Hydroporus are represented by about 260 species. No member of the group has yet been found in Japan, so that in this respect Japan and tropical Asia agree, and are very different from Europe. II. 10. — Group Agabini. {Vide p. 491.) This aggregate of the second degree is formed by ten primary aggregates which include one hundred and forty-four species. The size of the individuals varies from 6 m.m. to 14 m.m. of length, so that in the stature of the individuals the group stands at about the central point of the Dytiscidae. The upper surface is very rarely indeed possessed of a true punctuation, its place being taken by a reticulation of fine scratches, forming meshes of various shapes and magnitudes, according to the species ; sometimes this sculpture becomes exces- sively fine, and occasionally the surface is smooth and polished. The colour is usually obscure, or dark with a brassy tint ; few species are variegate. The characters of the group are that the semimembranous piece bordering the inner edge of the first ventral segment is smooth, and not thrown into transverse folds as it is in the Colymbetini ; the apex of the wing of the metasternum reaches, when the wing-cases are closed, to the edge of the epipleura ; the hind femur bears on its undersurface, at the extremity and quite close to the hind margin, a more or less developed group of ciHte ; and the side piece of the fourth and of the follomng ventral segments is comparatively broad. The first of these characters is merely a negative one, and by it -the Agabini depart from the Colymbetini to agree with the vast majority of the Dytiscidae. The character drawn from the relation of the points of the metasternal wings to the epipleurae is of little consequence, and moreover is not absolute but is rather one of degree : it depends on the fact that the metathoracic episternum (placed at the antero-external portion of the metasternum) proceeds backwards between the edare of the winsr-case and the wincj of the metasternum till it terminates as a sharp point, contiguous with the point of the metasternal wing ; this character however is not absolute, for in Dytiscus ater (No. 781) the exposed terminal portion of the episternum is not a sharp point, but is truncate ; the point of the metasternal wing in that species does not therefore reach absolutely so far as the epipleura, although it approaches very near indeed thereto. In those species of the aggregate that have the swimming legs but little developed, the femoral cilise are, Hke the legs themselves, less highly developed and perfect : TIIANS. BOY. DUB. SOC, N.S., VOL. U. " ^ 9SA On Aquatic Carnivorous Coleoptera or Dytiscidce. and in groups 7 and 8 of the genus Agabus, they are scarcely present, there being merely a few punctures grouped close together in a manner approximating to rectilinear, and each bearing a very obscure short hair or cilia. ^Yhere the swim- ming legs are highly developed (comp. Agabus, group 4), the punctures become confluent so as to form a regular line or depression, in which are placed the thick, contiguous, and regularly arranged cilise. In all cases however, including even those species where their development is rudimentary, the cilise are placed so as to form at their insertion a kind of linear depression parallel with and approximate to the hind border of the femur at its outer extremity. The width of the ventral side pieces is subject to some degree of variation, but so far as I have been able to examine the character, the variation is not great ; and it may be said that the width of the ventral side piece of the fourth segment is about one -half or one-third of the length. The aggregate may be described as a really natural one, inasmuch as the definition given of it will apply to no member of any allied group ; and also because that the primary aggregates of which it is composed are closely linked together. There is still however doubt as to its being actually isolated, because if other characters besides those above enumerated be taken into consideration, then a fresh combination becomes possible. Moreover each of the characters reappears, or at any rate is greatly approximated to, in allied groups. Thus the wide ventral side pieces reappear in Scutopterus, {htij. op.) although the rest of the members of the group with which that genus is associated (the Colymbetini) have the ventral side pieces narrow. As an instance of an imjiortant character that is variable in the group, but which has been left out of consideration by me, I may point out the penultimate stigma ; this in Agabus is quite small, while in Colymbetini it is transversely elongate. In Ilybius which I have included among Agabini, this stigma is also transversely elongate to as great an extent as it is in certain Colymbetini. C. J. Thomson, (and other naturalists have lollowed him in this), has made the want of a setigerous space on each of the middle of the third, fourth, and fifth ventral plates a distinctive character of the European Agabini, and has thus distinguished the group from the Colymbetini, in which the setigerous pore is present in a high degree of development. The character will not however bear when rigidly examined so high a degree of taxonomic importance as that assigned to it by the talented and most observant Swedish naturalist; for on careful examination it may be found present in Agabini in various stages of development. Thus in Dytiscus bipustu- latus (Agabus No. 751), a few scattered fine punctures bearing a very short hair may be detected about the middle of these segments, and in Dytiscus fuscipennis (Agabus No. 752) these punctures and setae are more highly developed, and are placed so as to form a diffuse patch on each side of the middle of the segment : in Ilybius they are present to a greater or less degree of concentration on the middle of the segment; On Aquatic Carnivorous Coleoptera or Dytiscidce. 933 in Ilybiosoma though very indistinct they are still more aggregate ; in Colymbetes gaudichaudi, (Leuronectes, No. 773), they are present in a very minute form, and in Col. peruvianas (Agametrus, No. 776) they are quite concentrated into a fovea and conspicuous, although not so large as in most Colymbetini. The Agabini are in their geographical distribution specially characteristic of cold and temperate regions, both in the northern and southern hemispheres, but more particularly in the northern ; and thence a few penetrate into neighbouring tropical regions ; the group is unknown in New Zealand and the Pacific Islands, although well represented in Australia; the few members found in South America, are probably inhabitants of mountainous regions. II. 0. — (Seven unassociated genera.) The seven aggregates placed between the Agabini and Colymbetini, are distin- guished from these two groups, by the fact that they do not possess the accumulation of cilise at the angle of the hind femur as found in the Agabini, and that the stigmatic rugae of the Colymbetini are also absent. As these are both purely neo-ative characters, and as in many other respects these aggregates differ much from one another, it seems to me that they cannot naturally be considered to form an associated group ; at any rate I must decline the responsibility of treating them as such at present. As regards the other characters made use of by me in the synthesis of the components of Agabini and Colymbetini, there are some observations that should be made in order to show the kind of variation these characters undero-o in these unassociated genera. The setigerous punctures of the lower face of the femur exhibit some most interesting peculiarities. In Copelatus they appear to be entirely absent, and the lower face of the femur shows a smooth impunctate surface. In Lancetes on the other hand there is an elongate sei'ies of setigerous punctures placed just on the middle of the lower face of the femur, that is about equidistant from its front and hind margins, at some distance from the base, and not extending to the outer extremity ; these punctures are seven or eight in number and vary in minor details of situation and development. In the other genera they are nearly entirely absent but whenever they can be traced it will be seen that they are placed, not near the hind border of the femur as in Agabus, but on the middle of its longitudinal axis, that is to say on a line drawn from base to apex of the femur at equal distances from its front and hind border. Thus in Lacconectus three or four obsolete punctures bearing each a very fine seta may be detected on the middle axis near the apex, and in addition to them one or two others extending towards the hind angle. The ventral side pieces in all these seven genera are more or less intermediate s o 3 934 On Aquatic Carnivorous Coleoptera or Dytiscidce. between tlie broad form displayed by the pieces iu the Agabini and the narrow one usually found in the Colymbetini. Thus in Matus the side piece of the fourth segment is as broad as in the genus Agabus, while in Coptotomus it is hardly broader than it is in certain members of the Colymbetini (Dytiscus grapii, No. 943, for example). In this respect therefore these genera connect the Agabini and Colymbetini. In most of the several genera the posterior portion of the metathoracic epister- num where it is exposed between the wing of the metasternura and the epipleura is very attenuate and acuminate; this is especially the case with Copelatus, Aglym- bus, Lacconectus, and Matus; while in Coptotomus the wing of the metasternum has so great an outward extension that it is almost invaded by the epipleura, that is to say that its termination cannot certainly be distinguished without slightly raising the epipleura from the breast. Thus this genus which by its ventral side pieces approximates to Colymbetini, by its metathoracic structure departs mostwidely therefrom. On the other hand Lancetes has the posterior extremity of the epister- num comparatively broad, and the apex of the wing of the metasternum distinctly though slightly separated from the epipleura, thus making an approximation to the Colymbetini. In these genera, the setigerous abdominal pores, relied on by Thomson as distinguishing the Agabides from the Colymbetides, undergo much vai'iation ; they are distinct on the fourth and fifth segments, but are wanting on the third in Lancetes and Coptotomus ; they are present on the third, fourth, and fifth segments iu Matus, but are only very slightly impressed ; they are present on the three seg- ments but are very small in Copelatus and Agiymbus; in Lacconectus they are also present but are so minute and rudimentary that they can scarcely be detected; and in Agabetes they are altogether wanting. II. 11. — Group Colymbetini. (F^fZe p. 605.) This aggregate is formed by four genera (comprising sixty-two species) ; the individuals are of moderate or rather large size, varying from 8 to 21 m.m. in length, and the surface is not punctate, but is either nearly smooth or possesses on the wing-cases a peculiar sculpture, wliich may be either reticulation or transverse scratching (aciculation), or even a kind of faintly raised sculpture having a slightly imbricate appearance. The semimembranous side piece of the first segment of the hind body {i.e., the part interposed between the stigma and the edge of the ventral plate) is marked by transverse rugse or furrows ; when tliere are any setigerous punctures on the hind femur, they form an irregular patch at the extremity, not however close to the hind margin, but widely separated therefrom. The most important of these characters is the presence of the stigmatic rugte, and it is the possession of these rugte that decides absolutely that a species shall be placed in the Colymbetini rather than iu the Agabini. These rugte are found outside the limitsof the Colymbetini only in the two genera Hyderodes and Dytiscus (formingthe On Aquatic Carnivorous Coleoptera or Dytiscidce. 935 •group Dytisclni), so that the chai-acter is of considerable taxonomic importance, and will probably be found to have a considerable functional value in the respiratory pro- cesses. I have examined a great number of species in addition to those I have actually dissected, and I have not detected any trace of the existence of these rugee, even in & rudimentary form, in any other Dytiscida?. The setigerous punctures on the hind femur are variable in the group, but they never assume the form which they constantly present in the Agabini. In some species they are entirely absent, Dytiscus calidus (No. 942), for example, while in a few other species of Rhantus (Dytiscus notatus, e.g.) and in most Colyinbetes they are rather numerous and conspicuous, and all the intermediate grades occur ; on the whole it seems that in the Colymbetini the tendency is for these setigerous punctures to disappear in the higher forms, while, on the contrary, in the Agabini it is in the higher species that they display their gi-eatest development and are most conspicuous. Three of the four genera forming the group agree in possessing the ventral side pieces narrow, and are thus sharply distinguished from the Agabini ; the fourth genus (Scutopterus) however departs abruptly from the other genera to agree in this respect with the Agabini. In Colymbetes and Meladema, the width of the ventral side pieces is so much reduced that the fourth may be described as linear, its leno-th beinar six or ei^ht times its breadth. In Rhantus the reduction of width of this piece is not so conspicuous as it is in the aggregates just mentioned, but still it is so great that the genus is by that character alone perfectly distinct from the Agabini ; in Col. graph, which so far as I have observed is the species of Ehantus that comes nearest to the Agabini in this respect, the length of the fourth side piece is four or five times its width; while in Agabini (as mentioned in that group, p. 932) the length is only about twice the width. Scutopterus however forms a striking exception to the other genera of Colymbetini, the length being only about twice the width. Another character by which the Colymbetini is contrasted with the Agabini is the greater development in the former group of the penultimate ventral stigma. There is however much variation in this respect, and it is not necessary to go into details of the variations, it is sufficient to remark that in this respect it is not Scu- topterus that most approaches the Agabini, but Rhantus. In Colymbetes this stigma is transversely elongate, while in some of the smaller Rhanti (Dytiscus exoletus, No. 951, e.q.) it remains smaller than it is in some of the Agabini. The hind tarsi show very frequently a lobing of the posterior margins of the hind tarsi externally, but to a very variable extent. In Colymbetes this lobing is extreme, while in Rhantus it is variable and in some species (Col. binotatus. No. 935, e.g.) is but slight. The claws of the hind tarsi are usually very unequal in the Colymbetini, and are nearly straight, the inner one being very large, and twice or three times as long 936 On Aquatic Carnivorous Coleoptera or Uytiscidce. as the outer one, but this character although it has been considered the essential distinction of Colymbetes (auct.) is not trustworthy, for in Colymbetes pacificus (No. 920) we have a species where the claws are almost positivel}' equal. The sculpture of the upper surface in the genus Colymbetes must not be passed over without remark, for it is almost without parallel in the Coleoptera ; this peculiar sculpture consists of elongate transverse striae on the wing-cases, giving rise to a file-like appearance ; it is to some extent sexual, and attains its maximum of development in the female of Dytiscus dolabratus (No. 971). It is all the more worthy of remark because the tendency of development in the water beetles is towards the attainment of a smooth and polished surface. lu the other genera of Colymbetini no trace of this transverse sculpture exists, but in Scutopterus a beautiful reticulation of fine but rather deep lines covers the upper surface, and in Meladema coriacea, a most peculiar scale-like sculpture exists. In Ehantus the surface is usually very polished and smooth, but in most species a very delicate excessively fine, minute reticulation is detected, with a good glass, on the wing- cases ; in the little developed Col. pacificus however the reticulation on the wing- cases does not exist, but is replaced by an obscure punctuation, while on the other hand in that highly developed species of Rhantus, Dytiscus pustulatus, the fine reticulation is very distinct, and like what exists in Ilybius. The Colymbetini as a whole are approximated by Ilybius of the Agabini, that aggregate displaying enlargement of penultimate stigma, lobing of the hind tarsi, and conspicuous inequality of their claws, characters which are all of them still more pronounced in Colymbetini. Scutopterus in Colymbetini approaches Agabini by the broad ventral side pieces, by the little lobing of the hind tarsi, and its sculpture which is a great development of Agabus sculpture. Although one aggregate of the Colymbetini thus approximates to Agabini, and one member of the Agabini approximates to Colymbetini, yet there is no approximation between these two aggregates themselves ; Colymbetini sends out as it were a pseudopod in the direction of Agabini, and Agabini a pseudopod in the direction of Colymbetini, but the two pseudopods so protruded are not in directions which lead one to .suppose they have had, or will have, any actual contact. Another approximation is made in certain respects to Colymbetini by Lancetes ; ttie species of that genus have in fact hitherto been universally placed by writers on the subject actually as part of the genus Colymbetes, and they approach the Colymbetini by their general appearance, by the comparatively blunt apex of the metathoracic episternum, by the comparatively large side wings of the metasternum and by the very unequal hind claws ; on the other hand by the truncate elytra, as well as by the little lobed hind tarsi, Lancetes tends rather towards Agabini than towards Colymbetini : and it is of course positively excluded from the latter group by the absence of stigmatic rugse. The mention of this latter character reminds us of another approximation On Aquatic Carnivorous Coleoptera or Dytiscidce. 937 made towards the Colymbetini — viz., by the DytiscinI ; for these are the only DytiscidaB except the Colymbetini that possess the stigmatic rugae : and this approximation is rendered more distinct by the fact that the Dytiscini show us perfected that wonderful development of the terminal stigmata of which the Colymbetini show the rudimentary stages ; but in this case again we must look upon the approximation as pseudopods, so to speak, not as indications of any past, present, or future amalgamation of the two aggregates, for in many others of the most constant characters of the Dytiscini there is no tendency towards contact, but quite the contrary. Thus Colymbetini are characterized by little extension of the coxal processes in the longitudinal direction, Dytiscini by a most remarkable extension of the processes in the longitudinal direction; Colymbetini have highly displayed lobing of the hind tarsi, which is nearly absent in Dytiscini ; Colymbetini have remarkably constantly very unequal hind claws, which is absolutely absent in Dytiscini ; so again we should find it with numerous other characters ; and more- over there is no tendency whatever for any one member of the Dytiscini to make any approach to any one member of Colymbetini. The conclusion to be derived from a careful consideration of the approximations between Colymbetini and other allies does not therefore in the least tend to raise or to confirm the idea of descent from a common ancestor ; the more thoroughly the details are mastered, the more does the realization of such an idea become hazy and elude the mental grasp. The siJecies inhabit specially the cool and temperate regions of the Old World, from whence a few have spread into adjacent regions. So far as known to me they are wanting in Australia, except that a species found almost everywhere in the Eastern Hemisphere occurs there ; as however two or three aberrant species occur in the Pacific Islands, such may also be found in Australia. A single very peculiar species is reputed from New Zealand, where also the same widely distributed Rhantus that is found in Australia occurs. Two or three aberrant species are known from Southern Africa and Madagascar : Madeira shows one or two very jieculiar species, but the Canary Islands have only a species found in Southern Europe, which is absent from Madea'a. Some species of Colymbetes are peculiar or nearly so to the arctic regions ; and in the New World besides the numei'ous species found in North America some others are found in or near the Andes, and one species of Rhantus is abundant in the warm parts of the New World (Dytiscus calidus, Fab.) II. 12.— Group Dytiscini. {Vide p. 632.) This secondary aggregate is formed by twenty-five species arranged in two genera. The size of the individual in all the species is large, not less than half an inch of length, and may attain one and a half inches. The swimming legs are rather slender and are terminated by two nearly equal curved claws ; the posterior margins 938 Oil Aquatic Carnivorous Coleoptera or Di/tiscidce. on the outer face of the joints of their tarsi are not ciHate ; the hind coxoe are never very large : the coxal jirocesses are elongate and narrow, and the coxal notch is very deep. The circular outline of the eyes is not interrupted by the side of the head over the insertion of the antennas. The stigmatic rugse on the side piece of the first ventral segment are present and highly developed. The stigmata of the two last ventral segments are large and highly developed. The front tarsi of the males are greatly dilated so as to form a large circular plate. These characters are amply sufficient to distinguish the Dytisciui in a certain manner from all the other secondary aggregates. They have usually been classified near Acilius and Cybister on account of the large, circular, front tarsi of the male, but this has been a mistake, for the only real ajiproximation they make to any insect outside of their own aggregate is to Colymbetes of the Colymbetides. In that genus we find as in Dytiscini, stigmatic rugse j^resent, and the posterior stig- mata more or less enlarged, whereas in Acilius and Cybister both these important peculiarities of the Dytiscini are entirely absent. Even as regards the male tarsi, the approximation of Dytiscus to Colymbetes is quite as decided as it is to C}' bister. It is true that the circular margin of the eye is common to Dytiscini and Acilius and Cybister, and not to Colymbetes ; if however Dytiscus be carefully examined as to this point it will be seen that certain species ( Vide D. lajjponicus and D. marginalis) have the outline of the eye distinctly, if slightly, infringed on by the side of the head over the insertion of the antenna, after the manner of Colymbetes, so that this point justifies the classification of the Dytiscini in the neighbourhood of the Colymbetini, certain members of which have the eyes not greatly emarginate. The enlargement of the terminal abdominal stigmata is a character of considerable importance and interest, and it seems remarkable that the few species constituting this group Dytiscini, should be the only ones of the whole family Dytiscida;, or carnivorous water beetles, that have developed to a great extent this respiratory structure : of which we find as it were the preliminary stages in some of the Colymbetini. The stigmatic rugae of the first abdominal segment are highly developed in tlie Dytiscini so that the group stands far higher than any other of the Dytiscidae in the development of its external respiratory apparatus. On the other hand in its powers of locomotion as displayed by the perfection of the swimming legs, the Dytiscini remain far inferior to the Thermonectini and Cybistrini, and even to some Colymbetini. The present habits and past history of the species of the group will no doubt be found to be correlative with these peculiarities of their organization. One of the most remarkable facts in this group is the existence, in numerous species, of two forms of the female sex. It is in this group that the dimorphism of the females so remarkable in the Dytiscidfe is carried to its gi'eatest extent ; and it is of especial interest tu notice that the two genera composing the group are On Aquatic Carnivorous Coleoptera or Dytiscidw. 939 extremely different as to the form assumed by the peculiar females, — so distinct indeed, that their development may be said to have been in opposite directions ; nothing could be more different than the deep regular grooves of the sculptured females of Dytiscus, and the dense irregular tubercles of the corresponding females of Hyderodes ; this fact would suggest the view that the resemblance or approxi- mation between Dytiscus and Hyderodes does not arise from genetic connection (or common origin), but is due to a j)arallelisni in the environment of the organisms during their evolution. Much has been written as to these dimorphic females of Dytiscus, but little or no light has at present been thrown on the subject ; and it will require a very extensive accumulation of observations and recorded facts, before successful generalization can be accomplished. It is worthy of note that the curious difference between the sculptured females of Dytiscus and of Hyderodes is completely paralleled in the Hydaticides, where the females of certain Acilii are sulcate like the females of Dytisci, while the females of certain Graphoderes are tuberculate like Hyderodes. The geographical distribution of the group is very peculiar. Dytiscus with its twenty-three species is confined to tjie northern hemisphere, whei'e it is specially at home in the northern jsarts of the Old and New Worlds ; while Hyderodes is peculiar to Tasmania and Australia, and seems especially characteristic of the former ; the large intermediate tropical zone comprising the parts of the earth richest in insects is absolutely destitute of Dytiscini, so far as we at present know. This peculiar restriction of a small group to the two most w^idely separated zoological districts of the world is remarkable, and is similar to that of the genus Pelobius, except that this latter does not occur in the New World. n. 13. — Group Htdaticini. {Vide p. 647.) This aggregate of the second degree is formed by the extensive genus Hydaticus (forty-five species), and the autogenus Prodaticus. The characters are similar to those of the more extensive group Thermonectini, except as regards posterior legs, and the metasternum. The hind coxa is not enormous, its length never being quite so great as its width, and frequently considerably less, so that the front border of the coxa is considerably separated from the middle coxa ; the suture between the wing of the metasternum and the episternum is a straight line (or nearly so) drawn obliquely from the front of the breast outside the middle coxa, to the epipleura. On the upper face of the hind tibia, parallel or sub-parallel to its outer margin is an elongate series of punctures, each bearing a stout furcate seta ; the spurs of the hind tibia are quite acuminate at the apex. The species are probably sparingly distributed over all the warmer and temperate parts of both hemispheres, but are absent from New Zealand, and probably from most of the Pacific islands. TRANS nOY. DUl.. SOC. N.S., VOL. 11. g E 940 On Aquatic Carnivorous Coleoptera or Dytiscidce. 11. 14. — Group Thermonectini. (Vide p. 672.) This aggregate of the second degree consists of fortj-one species arranged in four aofffreofates, and of two autooenera. The size of the individual is not less than one-third and scarcely exceeds two-thirds of an inch of length ; the surface is nearly always variegate, and may be punctate though it is generally very smooth and polished. The antennal portion of the head is short, sometimes extremely short, and the eyes are large. The thorax is destitute of a lateral margin ; the prosternal process is short and obtuse or rounded at the apex, and is received into a broad, short, shallow impression on the apex of the inter-coxal process of the metasternum, the middle cox£e being always somewhat widely separated. The hind coxsb are extremely large, their upper border is greatly arched, and never separated by a long space from the middle coxse, and often very closely approximated thereto ; the metasternum very elongate in the middle, terminates on each side as a slender side wing deflexed for a considerable distance outside the coxa, the band so formed is a little broader just before its termination than it is a little distance in front of that point ; the suture between the wing of the metasterrmm and the episternum (tliat is the piece at the outer anterior part of the breast) is very distinctly curvilinear ; and the most internal portion of the metathoracic epimeron may frequently be distinguished, even when the wing cases are quite closed, as a small angular piece, whose inner angle nearly touches the terminal angle of the side wing of the metasternum behind the a^iex of the episternum : as however the sutures between this epimeron and the adjoining pieces are very obliterated, it easily escapes observation even when really exposed. The coxal lines are always small, and sometimes quite obliterated, and even when most developed their anterior part is always very far indeed from attaining the anterior border of the coxa ; the supra-articular border when it can be distinguished is never ver}' narrow, and is frequently so broad that it forms nearly one half of the coxal lobe. The swimming legs are always highly developed ; the upper face of their femora is either smooth and polished, without any punctuation, or possesses some isolated punctures placed in a transverse manner on the basal portion and without any development of pubescence : the upper face of the tibia bears a short series of contiguous punctures (4 to 7 in number) placed near the middle of the limb in a transverse or obliquely transverse direction, each puncture bears a thick seta or spine bifid at the extremity ; the tibia bears at the apex two rather slender spurs, each of which when viewed in a certain direction is seen to have its apex not quite pointed but more or less minutely emarginate, though viewed in another direction the spur may appear quite acuminate. The aggregate is a perfectly natural one, distinguished by the form of the epi- siernal suture and the bifid extremity of the posterior tibial spui's; its curved epi- sternal suture is present in the adjoining Eretes, but the bifid extremity of the On Aquatic Carnivorous Coleoptera or Dijtiscidce. 9-tl tibial spurs is present in no member of the Hydaticides except the Thermonectini. The most aberrant member of the aggregate is Acilius, and it is quite possible that this may ultimately have to be separated in a more marked manner from the allies : but Dytiscus mediatus, No. 1057 (which however I have only been able to study in an incomplete manner), seems really to connect the other species of Acilius with Thermonectes. Thermonectini are found in all the warmer parts of the globe; two of the genera however (Acilius and Graphoderes) occur onlj^ in the temperate parts of the northern hemisphere. II. 15. — Group Cybistrini. [Vide p. 700.) This secondary aggregate or group consists of four genera comprising seventy-two species. The size is usually large, but varies much (from 14 m.m. to 48 m.m. of length). The outline is very perfect and continuous, and punctuation is absent, so that the surface is polished and smooth, except that the females of many species show a sexual sculpture on the upper surface consisting of short lines or scratches. The swimming legs are very powerful, their tibiae are very short and broad, and their apical spurs very unequal, the inferior one being very broad, and also longer than the othei*. The front tarsi of the males have the three basal joints greatly, frequently enormously, dilated in the transverse direction, and furnished on the underside with a large number of palettes, all quite similar to one another, and forming four crowded series; the large disc, formed by the dilatation of the three joints alluded to, is fringed along its margins with fringing hairs, and at the base or heel, between the basal row of palettes and the fringing hairs, there is an area of variable size, occupied by dense fine hairs or setae (pubescent area). The inter- mediate male tarsi are without any dilatation or thickening of the basal joints in the transverse direction. When there is a sexual sculpture present in the females, it consists of fine scratches or short lines, which may extend over elytra, thorax, and head, or some part, or parts thereof. The characters above enumerated are present in all the Cybistrini, and are quite suflBcient to validate the group; but it is also distinguished by numerous other ):)ositive and negative characters, not quite so definite or constant as the preceding ones. The two terminal joints of the male front tarsi and their claws are but little elongate, and the palettes of their undersurface are peculiar in their structure, each being oblong in form, and the outer portion of a peculiar thin or papery-like nature, while the basal portion of each is more solid and is deeply impressed or pitted ; the stalk by which the palette is connected with the tarsus is attached to this more solid basal portion : (the genus Spencerhydrus forms however an exception to the other Cybistrini in respect of the structure of the male feet, the terminal joints of 6 £ 3 y-t'i On Aquatic Carnivorous Coleoptera or Dytiscidce. the front tarsi being more elongate, while the palettes are nearly circular in form, and without the papery external prolongations). The intermediate tarsi of the male are sometimes furnished beneath with fine sexual jjubescence, but are sometimes quite destitute thereof; the claws are some- times distinctly, but never greatly, elongate, and are never slender. The claws of the hind feet differ considerably in the group, the differences being of sexual and specific, as well as of generic importance : they are always however extremely differentiated from the normal, or Cai'aboid, structure. The females, besides sometimes possessing a sexual sculpture, have often a peculiar form of the epipleura, inasmuch as this part near the base is flattened and twisted up so as to assume a more perpendicular direction: this torsion extends to different lengths according to the species, it generally commences a little behind the shoulder, and terminates before the middle or about the middle of the leng'th of the wino^-case. The males have always the underside of the posterior tarsi furnished at both edges with fine swimming hairs, while in the females such cilise are present only on the inner edge, except in the case of one or two species of Cybister, in which the hind tarsi of the females are ciliate on both edsjes as in the males. The stigmata of the hind body are all small, and are nearly circular", and difi'er little from one another in size or structure, except in the case of that on the apical segment, which is very small and circular, and passes through the integument in an oblique direction so as to form a sort of tube ; it is in fact formed as if it were made by a needle being pushed through the dorsal plate in the direction of the long axis of the body, instead of at right angles to it. The presternum is greatly thickened along the middle so as to give it extreme strength ; the thickening is sometimes so great that, being truncate in front, there is an exposed perpendicular face of considerable length at the front edge in the middle ; the prosternal process is short and thick, and gradually acuminate towards the acute apex, which is received into an impression of the metasternum of just the same form as the termination of the process itself; very little mobility is allowed by this articulation. In some of the Australian forms the presternum shows a deep longitudinal channel along the middle. The terminal portion of the wing of the metasternum is always very short (in the direction of the long axis of the body) owing to the fact that the upper border of the hind coxa, when it approaches its antero-external termination, is deflexed abruptly so that its termination is about at right angles to its previous direction; this peculiar and characteristic form of the metasterual wing is however departed from by the Australian genus Spencerhydrus. There is usually a distinct, or even considerable, space between the point of the metasternal lacinia and the epipleura ; in some cases however (Uybister latus. No, 1,105, and Spencerhydrus pulchellus, No. 1097) this interval is greatly reduced: in some species (Nos. 1,103 and 1,104) the termination of the metathoracic epimeron On Aquatic Carnivorous Coleoptera or Dytiscidce. 943 is very distinctly left exposed by the epipleura, while in other cases it cannot be at all perceived when the wing-cases are in the natural closed condition. The epipleuree show much variation in their width from species to species. The hind coxEe are always very largely developed, and their upper border of the form already described, The coxal processes never have a large extension either in the longitudinal or transverse direction ; the coxal lines are but little turned outwards near their termination, and they extend but a short distance in the anterior direction, so that they remain extremely remote from reaching the front border of the coxa, their extension forwards is however indicated by a curved series of punctures in front of the termination of the actual line. In the Australian genus Homceodytes the coxal lines are absent, and the coxal processes of rather unusual form. It is in this group of the Dytiscidfe that the swimming legs attain their greatest and most admirable development ; the femora are very broad, and the tibiae are often so thick and short that their length does not greatly exceed their breadth : in Dytiscus roeselii actual measurement shows about 3| m.m. of length, by 2g m.m. of breadth. The superior of the two apical spurs is ot slender form, and is more or less profoundly canaliculate along its inner face, and is either simply acuminate at the apex, or largely furcate there, or minutely tricuspidate ; the inferior spur is dilated and flattened, but is quite acute at the apex, and is longer than, as well as broader than, the other. The tarsi are very thick and their hind margins though sinuate are not distinctly lo bate-produced at their outer edges, and are destitute of fine ciliaB. Tlie claws are very vai'iable ; either there exists only a single thick, pointed, straight and immobile claw, or there are two, more slender, straight, equal claws, or the two claws may be unequal to a greater or less degree in length or thickness. It has been supposed that when there is only one claw present, it is because the two claws have become soldered and amalgamated into a single one ; and as a groove may be detected running along the length of the claw this is cited as a relic of the original distinction into two claws : this is however quite erroneous. When there is only one claw present it is because the second claw is undeveloped or rudimentary ; this second claw in point of fact is present in all degrees of development ; and moreover where there are two well marked claws present in the genus, each of the two claws may be seen to be deeply channelled {vide Cybister giganteus, No. 1,11 V) showing conclusively that the channel is not evidence of two claws being amalgamated. The Cybistrini are found in most parts of the world, except that they do not extend into the cooler regions, and must be considered as characteristic of the warmer and warm-temperate regions. The Australian species are much more aberrant than those found in any other part of the world. 944 On Aquatic Carnivorous Coleoptera or Dytiscidce. THIKD SYNTHESIS. (TRIBES.) III. L— Tribe NOTERIDES. {Vide p. 260.) This tertiary aggregate consists of two groups and two isolated genera, and comprises altogether only about eighty species, arranged in nine genera. The size of the individuals, occasionally very minute and never large, ranges from 1 to 8 m.m. of lenoth. The form is peculiar, the convexity is great, but is nearly limited to the upper surface ; the thorax and elytra are excessively co-adapted, and thus perfectly continuous in outline ; this outline is attenuate or acuminate behind. Varieoation of colour only occasionally becomes conspicuous, the punctuation of the surface may be considerable, or on the upper surface may be wanting, giving place to an extreme polish. The head is short, never in the least margined in front, but terminating in a sharp edge, so that the very exposed labrum continues the plane of the upper surface of the head ; the eyes are never very prominent, and their circular outline is a little notched by the side of the head over the insertion of the antenna. The antennee are short, and the shape of the joints is more or less dissimilar inter se ; the labial palpi usually have the terminal joint dilated, and frequently notched. The prothorax has always a lateral margin, which is often very broad and very little elevated. The front coxse are conical in form in some genera (Notomicrus, Hydrocoptus, Noterus), but approach more nearly to the spherical form than in the other Dytiscidse, and in Suphisini and Hydrocanthini they are nearly truly globose ; Pronoterus and Synchortus being apparently inter- mediate forms in this respect. The pro.sternum along the middle longitudinally, is usually of one plane from the front margin to the termination of the prosternal process, but in Colpius, it is incrassate in this direction, so that it projects beyond the coxpe, and forms a conspicuous prominent rectangle : the length of the pro- sternum in front of the coxse is sometimes extremely little (Suphisini), sometimes moderately great, (Noterus, Hydrocanthus) ; the prosternal process varies greatly, but it has never a slender acuminate terminal portion, and is usually very large, and becomes broader behind ; when small it is broad in proportion to the length ; it is always received into a highly developed fork of the mesosternum, and its posterior edge is extremely accurately co-adapted with the anterior part of the inter-coxal process of the metasternum. The front legs are in the more difierentiated forms of the Noterides modified in a remarkable manner, the modification reaches its extreme in the Suphisini and Hydrocanthini, but little or no trace of it can be found in Notomicrus and Hydro- coptus. Tiie femora in Suphisini become subcylindric and a little arcuate, and the tibia assumes a position in which the normally upper face looks outwards ; this part of the leg is at the same time modified in shape, and terminates in a large hook ; this hook is one of the ordinary spurs of the apex of the tibia developed in On Aquatic Carnivorous Coleoptera or Dytiseidce. 94.> a wonderful manner, and firmly fixed at its base in a cavity at the back of the tibia, so as to become rigid and immobile, and appear as if it were a prolongation of the extremity of the tibia ; in Notomicrus and Hydrocoptus, the modification ot the leg scarcely exists, but in Pronoterns the early stage of such an evolution may be seen in the fact that one of the two spurs at the apex of the tibia is a little elongate and curved. The male front tarsi are modified in a highly peculiar manner in some of these much evoluted forms, the basal joint being greatly incrassate, and of peculiar form, while the following joints are in comparsion very little modified. The modifications of the male legs are carried to the greatest extent in Noterus, and it would appear that the evolution of the front limb in that genus has been principally subject to a sexual direction, while in Suphisini the very great modi- fication is subject only to very slight sexual disparity, and probably corresponds to some vital operations common to the two sexes. The mesosteruum in the Noterides shows a great range of development, and in the higher forms its size and position is unusual amongst the water beetles ; in Hydro- canthini and still more in Noterini, instead of being articulated to the metasternum almost at right angles therewith, it is placed in a plane more or less continuous with that of the metasternum; this is not the case in Notomicrus; but in Synchortus this continuity of the meso- and metasterna is carried to its extreme, so that these two parts are but little discontinuous in their plane ; at the same time the area of the mesosternum becomes larger than usual; this development of the mesosternum, rare in the Dytiscidee, is found in water beetles of other families (Hydrophilidpe and Gyrinidae) and is no doubt the morphological correlative of greater functional jictivity of the intermediate legs ; these no doubt take a greater part of the locomotive activity in Noterides than they do in the other tribes of Dytiscida3. The increase in the area of the mesosternum is entirely due to growth in the epistemum, which becomes very large, the epimeron not sharing in the least in this inci'ease, but rather becoming smaller and more linear. This diminished size of the mesothoracic epimeron is one of the characteristics of the Noterides, but it is found in other Dytiscidse, (especially is some members of Bidessini) and cannot be used for distinguishing or defining the Noterides as suggested by Crotch. In no case however, so far as I am aware, except in the Noterides, is it accompanied by an increase in the episternum ; the epimeron, even in Notomicrus, where the characteristic structure of the Noterides is so rudimentary, is small in comparison to the episternum. The angle of the epimeron which touches the angle of the metathoracic-episternum is but little conspicuous, and very obtuse ; and owing to the enlargement, above described, of the episternum, the epimeron at this point is much diminished in breadth ; these characters although developed to a less extent in Notomicrus are yet extant in it, and the Noterides may be correctly defined as possessing a mesothoracic epimeron of very small area in comparison with tlie 94G On Aquatic Carnivorous Coleoptera or Dytiscidce. epirftenium, and very small in width at the posterior angle, which itself is obtuse and little prominent. This though true of all Noterides is not untrue of all other Dy tiscidse, for such a description applies also to Huxelhydrus of the Bidessini. The fork of the mesosternum always is highly developed, and accurately coadapted with the inter-coxal process of the metasternum, and one of the most striking charac- teristics of the Noterides is. the accurate coadaptation of the three parts, prosternal process, mesosternal fork, and inter-coxal process of metasternum ; it is by this that the immobility of the prothorax is secured ; and the perfect continuity of the prothorax and after body is thus rendered possible. The middle legs in the higher Noterides are a good deal thickened and flattened out (see especially Synchortus). and their coxse are small and globular ; they play no doubt, as above observed, a considerable part in the locomotion of the individual, and have undergone a considerable change to facilitate this. This is quite in opposition to the higher forms of other groups of Dytiscida;, for in them the middle legs do not share in a correlative manner the development of the hind legs into S'wdmming organs. The metasternum is peculiarly formed in the higher Noterides ; its middle part is prominent, and very closely soldered with the prominent coxal processes, so that the suture is more or less nearly obliterated ; it is short in the middle, and forms only a very obtuse point there ; extending laterally this suture has very little anterior direction, but owing to the brevity of the metasternum, it is never far separated from the middle coxa, and sometimes indeed almost touches the coxal cavity near its middle {vide Noterus), it then proceeds almost directly outwards with a slight slope in the backward direction till it attains the episternum ; its anterior part in the middle always forms a very distinct and rather broad inter-coxal process, and on the outside of the coxal cavity extends a good deal forwards ; a lateral wing of the metasternum is thus formed, having a very peculiar shape, this shape depends on the middle coxa having, as it were, by the unusual growth of the mesosternum, been forced backwards so that its cavity intrudes greatly on the metasternum, and as the metasternum is short, and has suffered compression from behind in the middle, by the growth of the peculiar and enormously developed coxal processes, the consequence is that on the space between these two forces it has become very reduced, and the lateral wing is almost cut off from the middle part. This peculiar structure is best studied in Noterus {vide fig. 39) and Synchortus, but where the swimming powers of the middle and hind legs are but little developed, as in the Suphisini, all that can be said is that there is such a form of the parts as might be developed into the peculiar structure described, by such changes as are necessary to improve the swimming powers. Thus in Suphis dilformis the middle coxa intrudes comparatively little on the metasternum, and the hind femur when flexed for the stroke of propulsion can be brought comparatively little towards the middle, so that its stroke is nmch less powerful than it is in Noterus and On Aquatic Carnivorons Coleoptera or Dytiscidce. 947 Hydrocanthus where it can be brought much nearer to the middle line of the body. In Suphis difFormis, however, as in the higher Noterides, the front border of the coxa attains its greatest anterior extension near the middle of the body and thus forms a striking contrast to the Hydroporides, where the greatest anterior extension of the coxa is near the outside ; in this respect the approximation of the more primitive forms of Noterides to Pelobius is very decided, and in fact, so far as the shape of the metasternum and hind coxae go, there is no great difference between Pelobius and Suphisini. The hind coxae are in the Noterides modified in a very peculiar manner ; the coxal processes are enormously developed and are projected on to a different plane from the external lamina of the coxse, so as to form a prominent platform ; a concavity or elongate axilla is formed by the inner portion of the outer lamina being pushed in above this prominent platform, and this axilla extends the whole length of the coxa, and as the middle of the metasternum is more or less prominent in a similar manner to the coxal processes, a kind of prominent platform continuous with the prosternum is formed, extending the whole length of the breast. This platform is extremely conspicuous and remarkable where the swimming legs are highly developed (especially in Hydrocanthus), but scarcely exists in Suphis, for although in it the elongate axilla formed by the coxal processes exists, there is not the least prominence of the middle of the metasternum. The coxal processes show no trace of the existence of any coxal lines or coxal borders, and their posterior outer angle is acute or rectangular ; the coxal cavities are either distinctly separated or absolutely contiguous : Hydrocoptus is the only genus in which the coxal lines can be detected, they extend the whole length of the coxa and mark off a fine coxal border. The swimming legs vary greatly in their development ; the most characteristic peculiarity is that in the higher forms the tarsi do not share in the incrassation of the femora 'and tibiae to the same extent as in other Dytiscidae, thus in Hydi'ocanthus, the tarsus is not half so broad as the tibia ; the tibia moreover never becomes shorter than the femur ; and it seems, therefore, that it plays to a large extent the part performed by the tarsus in other Dytiscidae; the spurs of the tibiae are never greatly incrassate, but one of them is occasionally beautifully serrate along its inner face (Hydrocanthus laevigatus). The tarsi have the basal joint always very elongate in proportion to the others ; and the claws appear to be always small and insignificant, and so far as known are both always present, and nearly equal. Ciliae at the hind angle of the posterior femur are either present or not ; in Hydrocanthus they attain a greater development than in any other Dytiscida3. Both the front and middle tarsi in the Noterides are distinctly 5-jointed, and there is no bilobing of the third joint ; when the male front tarsi are thickened, the incrassation is chiefly confined to the basal joint, and there is not the least TRANS. ROT. DIB. SOC , N.S. VOL. II. 6 F 948 On Aquatic Carnivorous Coleoptera or DytiscidcB. tendency for the three basal joints to be co-adapted and dilated to form a saucer ; the clothing of the under surface is never more, or other than, a few small palettes. The Noterides are characterized specially by the structure of the hind coxse ; the anterior border of this part attains its greatest forward extension umch nearer to the middle (longitudinally) of the body than it does in auy other Dytiscidae, and thus a peculiar shape is given to the wings of the metasternum ; and the interior lamina of the coxae is very separated for its whole length from the external lamina, and projects and foims an axilla, into which tlie interior Ijorder of the hind femur is I'eceived when it is flexed. This structure of the hind coxae, under various modifications, is found in all Noterides, and is not found in any other of the Dytiscidaj, except the totally distinct Pelobius (in which, inter alia, the scutellum is visible). There are some other characters by which most of Noterides may be recognized, but they are not quite so constant or peculiar as the coxal structure. These are : first, the small size of the mesothoracic epimeron in comparison with the ejjisternum and its sublinear form ; second, the accurate adaptation of the prosternal process to the inter-coxal process of the metasternum ; and third, the unusual development of one of the spurs of the front tibia to form a hook, I now proceed to discuss briefly the amount of variation of these characters within the limits of the tribe itself, and to what extent they are possessed by other Dytiscidae not included in the tribe. The hind coxae var}' very much in their area as in other Dytiscidae, but whereas in other Dytiscidae when they increase their area and encroach on the metasternum the anterior border attains its greatest ajDproach to tlie front of the body more or less near the epipleurae, in Noterides, as already stated, this greatest apjiroach is made much nearer to the middle line of the body, and so at a greater distance from the epipleura ; this character so far as can be seen is absolutely constant, but it cannot be tested in the minute Notomicri, for in these the outline of the coxa cannot be distinguished from the metasternum; but there is no reason for supposing the geims to be really an exception to the other species in any other respect besides that of the obliteration of the suture : Pelobius is the only Dytiscid outside of the Noterides in which the coxa has at all the Noterid form ; and although nothing can look more dissimilar than the coxa of Pelobius and one of the higher Noteridae such as Hydrocanthus, yet if we compare it with one of the lower Noterides, such as Suphis or Colpius, the likeness of the two is readily perceived. I'ulobius has moreover the internal lamina of the coxa abruptly distinguished from the outer lamina for its whole length longitudinally, and thus again resembles the Noterides ; this latter peculiarity of the structure of the coxa occurs however in other genera of Dytiscidae, such as Agabinus and Hyderodes, very widely separated genera belonging respectively to Agabini and D3'tiscini. The small size of the mesothoracic eiiimeron — one of the features characteristic On Aquatic Carnivorous Coleoptera or Dytiscidce. 949 of the Noterides — appears to be true of all the species of the tribe, but it is likewise found insomeBidessini, in Sternopriscus, and even (though not so remarkably) in Pelobius; no\v' as all these widely different forms have in common the fact that the Tnesosternuiii is placed on a plane more continuous with the plane of the meta- sternum than it is in other Dytiscidce, it is clear that the small size of the meso- thoracic epimeron is correlative with the less amount of change of position of the mesosternum, or in other words, just so much as the mesosternum has been bent towards the metasternum, just so much has the epimeron increased in size : although Bidessus and Sternopriscus resemble Noterides in the small size of the epimeron, they do not agree with it in its comparative obliteration at its upper or episternal angle ; this is clearl}^ because growth of the mesothoracic episternum has gone on in Noterides (owing to greater use of the middle legs in locomotion), while no such growth has taken place in Bidessus and Sternopriscus. 'i'hus we see that the form of the mesothoracic epimeron in the Noterides is the result of the little change of plane of the mesosternum plus the unusual growth of the episternum ; and we can clearly see that these peculiarities are properly considered as amounting to evolution from more primitive to higher forms, and we see further that the likeness presented by other water beetles in this respect is not due to any genetic connection or common ancestry, but rather should be looked on as community of structure owing to similarities of evolution. Another peculiarity of the Noterides, viz., the relation between the prosternal process and metasternum, need not occupy us long ; it is very striking in Hydro- canthini, but much less so in the other groups, and all that need be said is that whereas in Hydrojiorides and some other groups accurate adaptation of these parts has been gained com^oaratively late in the process of evolution, on the other hand, in the Noterides it has been a striking feature even in some of the early forms. Sternopriscus, which has been just alluded to as approximating to Noterides by one part of the structure, is in this resjiect abruptly different, it being one of the forms where co-adaptation between the prosternal process and metasternum is most incomplete. The unusual development of the spur at the apex of the front tibia, is not present in all the forms, it seems to be absolutely deficient (so far as I can see) in Hydro- coptus and Notomicrus, but it is present in all the higher forms, and in some of the lower ones, and attains its greatest evolution in Suphisini, which in some other respects are to be considered low or primitive forms. Although, so far as we know of them at present, and probably really at the present epoch, the Noterides form a very fragmentary tribe, yet it is one which is very well adapted for studying in connection with eA'olution ; and I have come to the conclusion that certainly there is no ancestral relation between the different forms comprised in it ; after careful consideration I feel sure that no species, of it can be considered the ancestor of any other species, no genus the ancestor (jf 6 F 2 930 On Aquatic Carnivorous Coleoptera or Dytiscidte. any other genus, iind a fortiori, no group the ancestor of any other group ; neither can I find it credible that the similarities visible are due to descent from a common unknown ancestor. The geographical distribution of the tribe is extensive, but fails to reach the cooler temperate regions, or New Zealand and the Pacific islands. III. 2.— Tribe HYDROPORIUES. {Vide p. 319.) About five hundred species, arranged in twenty-six genera, and forming five secondary aggregates or groups (in addition to two isolated genera) form this tertiary aggregate or tribe. It is therefore by far the most extensive of the tribes of Dytiscidse. They are all small insects, the largest size attained being about 6 m.m. of length, and the surface of the body is nearly always punctate. The tribe is specially defined by thu structure of the prosternum, which is deflected or bent between the front cox?e so as to be very discontinuous in the plane of its direction with that of the prosternal process. The anterior border of the hind coxa is directed forwards as well as outwards, in such a manner that its greatest extension in front is at a point nearer to the epipleura than to the middle line (longitudinally) of tlie body. The metathoracic episternum penetrates to the middle coxal cavity. The front and middle tarsi have the three basal joints formed so as to show a flat sole clothed beneath with a kind of glandular pubescence : these tarsi have usually only four visible joints, the joint between the third and (true) fifth joints being reduced to a mere knot ; in the cases where this rudimentary joint is quite conspicuous (Necterosoma, Sternopriscus) it usually remains small in comparison with the adjacent joints. The scutellum is usually quite con- cealed, but in Celina is large and conspicuous. Of the above characters, that drawn from the structure of the prosternum is the one by which an insect may most certainly and readily be identified as a member of the ti'ibe ; but the tarsal structure and other points must be also taken into consideration, for if not, Sujshis (a jjrimitive form of Noterides in the Dytisci fragmentati) might be supposed to belong to the Hydroporides, as the form of its prosternum corresponds to the above definition. The Hydroporides show no tendency whatever to thickening or strengthening of the anterior parts of the prosternum along the middle, as do all the higher and larger forms of the Dytiscidaj : on the contrary, the anterior parts of the prosternum are ahvays feeble and but little developed, and afibrd but slight protection to the front coxae. The anterior transverse band of this part is always small, and has not the least tendency to being arched in the transverse direction : the band between the front coxa3, connecting this transvei'se part with the prosternal process, is never more prominent than the coxae, and is often more or less depressed between them : the prosternal process itself is much more variable and may attain a large development On Aquatic Carnivorous Coleoptera or DytiscldcB. i)51 (Dytiscus dorsalis, Celina, Sternopriscus, Hydroporus ublitus, e.(j.), ox may be very small, as in Dytiscus ovatus, (Hyphydrus, No. 347), and numerous Hydropori. The reduction of the pieces of the prosternura seems to attain its maximum in Hyphydrus, where the anterior and inter-coxal bands form a mere slender frame for the setting of the coxa?, which are longer than is usual in the other Hydroporides. The pro- sternal process is not only variable in size but is exti'emely so in form ; its junction with the inter-coxal band is frequently very conspicuous and it may project at the point of junction as a kind of angular or tubercle-like prominence ; this is especially the case when the prosternal process is thick and powerful as in Pachydrus, where the prominence alluded to is clearly seen to be the result of a thickening and growth of the prosternal process, while no corresponding development of the inter-coxal band has taken place ; hence at the point between the front coxa3 where occurs the junction of the thickened prosternal process with the feeble inter-coxal band, there is an angular prominence. It is worthy of remark that the New World seems to have been more favourable to the production of this thickening of the prosternal process than the Old World has been ; not only does it reach its maximum in the New World Pachydrus, but it will be found to occur with great frequency in North A.merican Hydropori, and indeed in certain cases {e.g., Nos. 492 and 493, Deronectes prosternalis, and Dytiscus griseostriatus) is almost the only character by which a New World species is distinguished from an Old World one. In short though the members of the Irlydroporides agree among themselves in showing a feebleness of the anterior parts of the prosternum, yet that feebleness is accompanied by great variety of structure, and I do not see the least reason for considering it as evidence of genetic connection among the insects possessing it. Its functional value will probably be expressed in terms defining the nature of the movements of the head and front legs performed by the insects. The front and middle tarsi of the Hydroporides show great variety, although agreeing in the generalized and guarded definition given above. Moreover they show much difference in the sexes of the same species, and this renders their use as a means of definition somewhat more difficult. Thus though the thi-ee basal joints agree in being more or less fiat, and in presenting beneath a sole clothed with pubescence, yet as will be seen by examining the sexes of Dytiscus ovatus (No. 347), this structure is much more conspicuous in the males than in the females, for in the former the three joints are comparatively broad and flat, and present a well marked sole beneath, while in the female they are compressed in such a way as to be extremely convex transversely on their upper face and to present but a small surface or sole beneath. It is the rule throughout the aggregtite that the males have the front and middle tarsi broader, and so displaying the character- istic structure more markedly than the females. Although the male tarsi may be said to have the basal joints dilated, they never have any tendency to assume the beautiful patellate form occurring in the corresponding sex of the Hydaticides, Dytiscini and 952 On Aquatic Carnivorous Coleojytera or Dytiscidce. Cybistrini, where not only is the dilatation of the three joints in question on the front feet enormous, but it is accompanied by a shortening and coadaptation which render them in fact a sinsrle orofan or saucer. Neither do the males show an incrassation of the basal joints of the tarsi such as exists in Agabiniand Laccophilini, where an enlarged sole is gained by an increase in the whole circumfei'ence of the joints, the increase being in fact as great in the vertical as in the horizontal direction of each incrassate joint. Putting aside these sexual differences in the tarsi, other interestingf variations in the basal joints, especially in the outer of them — the third joint — may be noted ; this is almost subquadrate or truncate-cordate in certain forms (H}'phydrus, Macro- vatellus, e.g.) with the upjier surface bearing a short groove at the extremity for the insertion of the basal joint; while in others (many North American species of Hydroporus of groups 1 and 2), it is deeply grooved, or indeed cleft nearly to the base, so as to exhibit elongate lobes, the terminal joint being inserted near to its base. In this case the structure is essentially that of the tetramerous Coleoptei'a, as represented by the Curculionidfe, Phytophaga, Longicornes, &c. : and there is everj^ reason to believe that this modification of structure is essentially similar in its functional value in the two cases. The Coleoptera which walk or run on the surface of the earth ha,ve slender cylindric tarsi, destitute of clothing beneath or bearing only a few rather rigid setaB, while those groups which live much on foliage have the three basal joints of the tarsi dilated to form a sole, which is clothed beneath with a peculiar pubescence, while the terminal joint is not used in walking but is inserted so that the claws terminating it are held up from the surface ; so in the Hydropori mentioned we have good grounds for supposing that the species are much in the habit of frequenting and walking on aquatic plants, while in the other tribes of Dytiscidfe the front and middle tarsi (when not modified for sexual purposes) have essentially the structure of the Carabidse. As another striking instance of the relation between the form of the tarsi and these habits of the species, I may be allowed to mention the genus Stenus of the Staphylinidse, some species of which run swiftly on earth and mud and have filiform elongate feet, while others which live nuich on plants have the tarsi broad with a lobed penultimate joint and the surface clothed beneath with fine pubescence. In these Steni the tarsi however remain five-jointed and have not as in these specialized Hydropori acquired the fully characteristic structure of the tetramerous Coleoptera. In the fact therefore that the structure of the tarsi of some Dytiscidte diflers fundamentally but little, scarcely at all, from that of some Curculionidfe, we have clearly a clue to decij^hering certain of the environments under which they have been developed. It is worthy of note that where the true fourth joint of the tarsus is conspicuous, as in Sternopriscus and Necterosoma, it is accompanied by an elongation of the fifth joint, and this elongation is different sexually, being always somewhat, ofteji greatly, more developed in the males. A striking example of this may be pointed On Aquatic Carnivorous Coleoptera or Dytiscidce, 953 out in Sternopriscus oscillator, where the luiddle tarsi of the male are very elongate and their true fourth joint is developed to such an extent that it actually very nearly equals the third joint. It is a further interesting fact that the only two genera, — and they are widely different from one another — in which the true fourth joint of the tarsi is very con- spicuous, are both peculiar to Australia. Also it should be noted that some otthe species of Sternopriscus, differing as they do from all other Dytiscidas by the great development of the true fourth joint of the middle tarsi of the males, have no two species in which this part is similarly formed. 1 judge from this that each species has developed the peculiarity independent of the others, and that their all possessing it (in various ways) is no proof of genetic identity. There seems reason to believe that the Hydroporides have had ancestors with five-jointed front and middle tarsi ; not only because the joint usually wanting (the true fourth joint) remains quite visible in certain genera, (Necterosoma, Sterno- priscus) ; but also because the posterior or hind tarsi are always five -jointed throughout the tribe. And as in all the carnivorous Coleoptera except these Hydro- porides, the front and hind tarsi have the same number of joints (fivej, and as this is at present the case in a certain number of Hydroporides (where the fourth joint is greatly reduced though still conspicuous), we may reasonably suppose that these Hydroporides which have now only four joints on the front foot, had formerly five joints, and that the true fourth joint has become reduced and lost, in conformity with the plant-frequenting conditions of their existence ; it being the rule that beetles which walk on vegetable substances have only four-jointed tarsi. The pos- terior tarsi remain always five-jointed because they are used not for walking on plants but for sswimming, and for this purpose reduction in area would be very disadvantageous. The scutellum displays in this aggregate great diversity, though as it is concealed from view a superficial or misleading conformity among the species is suggested. In Hydrovatini it is found in its minimum of development, so that when the prothorax is separated from the after or middle body the scutellum still appears to be absent, indeed the mesonotum in these insects seems to be excessively small and fra- gile, and owing to the perfect way in which the elytra are locked together, I have not succeeded in getting a view of the mesonotum without rupturing and destroying it. In Dytiscus ovatus (Hyphidrini) the scutellum exists as a moderately large membranous plate ; the posterior margin is truncate and presents a sharp edge, but this is not produced into a fine triangular plate : the anterior margin of the scutellum is also truncate and is narrower than the posterior one. In Dytiscus duodecimpustulatus (Hydroporiiii^ Deronectes,) the anterior pieces of the mesonotum are larger than in Dytiscus ovatus (Hyphidrini) but the scutellum is not larger, and is of a different form, being rhomboidal, and angulate both in 954 071 Aquatic Carnivorous Coleoptera or Di/tiscidce. front and behind, and its posterior part projects as a fine edge, which laps over the basal sutural angles of the wing-cases when they are closed. In Hydroporus nigriceps (Hydroporus, No. 576) the anterior pieces of the mesonotum are smaller than in Dytiscus duodecimpustulatus ; the scutellum is however similar in form, but it is received into an angular depression at the base of the elvtra, for the reception of the middle of the base of the prothorax, whereas in D. duodecimpustulatus, the elytra are truncate at the base. Tn all the above insects the scutellum is completely concealed when the prolhorax is in its natural position. In Hydroporus oblitus, however, a small portion of its apex remains uncovered, and in Celina it is largely visible. I have not been able to obtain a specimen of either of these insects for more detailed examination. Thus the definition "scutellum invisible" applied to tlie Hydroporides covers and includes a series of diverse and interesting modifications. The functional value of these parts is con.siderable. Nothing more perfect can be imagined than the manner in which the elytra when closed are locked together by different portions of their structure and by projections of the mesosterna and mesonota ; a complicated set of surfaces and edges is so beautifully coadapted that there cannot be the slightest admission of fluid from without, and great strength is attained although the material used is very small. Almost everytbing remains to be done in the study of these pai-ts, for they have hitherto been but little examined. The Hydroporides are found in all parts of the world, except some of the Pacific islands. The Hydrovatini and Bidessini are widely distributed in the waimer p.arts of the world ; the Hypliidrini are more specially African ; and the Hydroporini Palajarctic and Nearctic ; while Sternopriscus is peculiar to Australia, and Celina to the warmer parts of the New World. There exist in the Hydroporides numerous grades of development of various organs, and this instability of the structure, combined with the fact that some of the gradations can clearly be distinguished as higher or lower than others, suggests the idea that some of the species or genera may be placed in an ancestral relation to others. Hydrovatus, having very poorly developed locomotive organs, possesses a great resemblance to some of the species of Coelambus, such as Dytiscus inaequalis, and this latter form in the structure of its swimming legs might be con- sidered to be an advanced Hydrovatus, the apparent connection between the two being greatly increased by their possessing in common a margined head, and a genicular impression on the epipleura, as well as by the general form, by the sculpture, and by the structure of the antenna. Thus a truly genetic relationship seems to be suggested. But on continuing the comparison the probability of any such relationship quite disappears, for while in Hydrovatus the middle and hind coxse are widely separated and the prosternal process of remarkable width and peculiar form, and the posterior coxal cavities covered and protected, in Dytiscus On Aquatic Carnivorous Coleoptera or Dytiscidce. 955 iiifeqiialis we see the other extreme in these respects, and we find a small and acuminate prosternal process, with very approximate coxae and exposed posterior coxal articulations. If we take a third form of the Hydroporides, Dytiscus duodecimpustulatus of the genus Deronectes for example, and continue our com- jiarison, we find in it a general shape and swimming legs more adapted for aquatic locomotion ; the head is completely without margin and the labrum is quite exposed. The middle and hind legs are less approximate than in D. intequalis, the prosternal process is much broader and the posterior coxal cavities more pro- tected. As the result of the comparison of the three species we find then, that having regard to the general form and the development of the swimming legs, a supposed line of descent, thus — 1. Hydrovatus ; 2. Coelambus ; 3. Deronectes; while if we look to the distance of the coxae, the form of the prosternal process, and the protection of the hind coxal cavities, the order would be — 1. Elydrovatus ; 2. Deronectes ; 3. Coelambus ; and if again we look to the structure of the head, we find that Hydrovatus is the intermediate form, and the line of descent would be — 1. Coelambus {D.insequalis) ; 2. Hydrovatus; 3. Deronectes. It ajjpears, there- fore, that a natural classification in which all the structures are dealt with o-ives no support to the idea of a genetic relationship between these three forms ; while in an artificial classification — a classification in which some one or two characters should be taken into account to the exclusion of others — the three forms would stand in different relationships to one another according to what jsoint of structure should be selected as the basis of the classification. It does not however follow that in a natural classification it would be incorrect to speak of any one of these three species as being higher than the others, for if we were acquainted with all the points of structure, and knew accurately their functional value, we would be able to assign to each organ a numerical value, indicative of its orade of develop- ment (as for instance, in the case of the swimming legs, 1 to Hydrovatus, 3 to Coelambus, and ."3 to the Deronectes), and by adding all these together we would be able to say with certainty which was absolutely the higher form ; but because we could do this it would not in the least follow that the lower form was ancestral to the higher. This is equally applicable to the relations of the anomalous Pelobius and Amphizoa to the other Dytiscidse ; although they are less highly developed as Dytiscidre there does not appear any reason for supposing them to be truly ancestral forms to their more highly developed allies, and thus the fact that certain of the lower forms have numerous points in common does not indicate a genetic relationship between them; the similarities found are indeed indicative not of such relationship, but rather of similarity in the stage of development of some one or more of the points of structure. TRANS, nor. DUB. SOC., N S., VOL. II. g Q. 956 On Aquatic Carnivorous Coleoptera or Dytiscuhe. III. 3.— Tribe COLYMBETIDES. (F/c/e p. 490.) This tertiary aggregate comprises two secondary aggregates and seven unassociated genera placed between them, in all twenty-one genera, with about three hundred and twenty species ; so that it is, next to the Hydroporides, the most extensive of the four tri bes of the family. The tarsi are all invariably quite clearly five-jointed, and the scutellum is alwa\ s visible at the base of the elytra ; the inter-coxal process of the metasternum always connects with the mesosternal fork, and the apex of the prosternal process always reaches over or between the middle coxae, and rests on the apex of the inter-coxal process of the metasternum which is more or less grooved or impi-essed for its reception. A line drawn along the middle of the prosternum, from front to back, is nearly or quite a straight line,"" but occasionally, although raiely, the front portion of the prosternum is so much thickened in this middle line, that it presents in front a distinct vertical edge. The hind coxae are very rarely less than of moderate size, and are sometimes very large : the side wings of the metasternum are very variable in size. The posterior coxal cavitiesare always absolutely, or very nearly, conjoined, and are always protected by free, projecting coxal lobes or processes. The swimming legs, sometimes quite slender, are in the highest species well developed, but are never extremely thick ; the hind margins of the joints of their tarsi are never externally closely set with adpressed cilia;, and they are always terminated by two visible claws, which however are of very variable develop- ment, sometimes being very small and equal, while as the other extreme the inner one is very elongate and the claws thus become very unequal ; the spurs of the hind tibia a)"e never incrassate or bifid at their apex, and the hind tibias themselves never show even the rudiments of the development of a patch of spur-Hke setse at the outer and upper angle of the extremity of their inner face. The Colymbetides are thus most essentially separated from the Hydroporides, by the prosternal sti'ucture, and in a rather more subordinate degree by the con- spicuously five-jointed front and middle tarsi and the visible scutellum. Tn speaking of the Hydi'oporides I pointed out that that group never exhibited any tendency to thickening of the prosternum along its middle line, and that the anterior portions of the prosternum were always placed on a very different plane to the posterior portions. In the Colymbetides the reverse occurs. The prosternum is always more or less thickened along the middle, and projects, so that the front coxte are as it were embedded in it, and there is but little change in its direction or plane from the point of the prosternal jjrocess to the front margin. The thickening is found in all degrees of development, it is very slight in the lower forms of Agabus, but in the higher species is very much more developed and reaches its maximum in Coptotomus : in that genus as a consequence the prosternum * That is to say, is a straight line drawn on a plane. On Aquatic Carnicorous Coleoptera or Dytiscidce. 957 shows at the front edge in the middle a distinct vertical face, placed at right angles to the plane of the prosteruum; a superficial approximation to the definition of the pros- ternal structure of the Hydroporides is thus suggested ; but a very slight examination is sufficient to show that so far from this being the case, Coptotomus is of all the Colymbetides the farthest removed by its prosternal structure from the Hydro- porides. In Hydroporides it is the inter-coxal band of the prosternum that is placed on a different i^lane to the prosternal process, the very small transverse band forming the front of the prosternum being again nearly horizontal in plane like the prosternal process ; in Coptotomus the horizontal plane is continuous from the apex of the prosternal process to the front margin of the prosternum, and then there occurs the vertical free face of the incrassate portion. Dytiscus fuscipennis (Agabus, group 21) makes however a genuine approach to Hydroporides in the j)ro thoracic structure, the band between the front coxte being placed, in its relation to the prosternal process, somewhat as in that group : this interesting similarity is not however accompanied by any other approach in D. fuscipennis to the Hydroporides, so that we may say that those influences that have caused this insect to approach Hydroporides have been confined in their operation to its prosternal structure. The front and middle tarsi are always conspicuously five-jointed, the fourth joint being as far as its length goes, as much developed as the basal ones, and thus a conspicuous contrast with what is usual (but not absolute) in Hydroporides is exhibited. In the male sex of Colymbetides there is always a greater or less incrassation of the three basal joints of the tarsi, and we find in certain members of the aggregate that this incrassation is displayed to a less extent by the fourth joint (vide Colymbetides), a most unusual character in the Dytiscidee. Still how- ever it is interesting to remark that in both Colymbetides and Hydrojjorides in certain exceptional cases, the sexual development exhibited by the three basal joints of the tarsi is accompanied by an unusual development of the fourth joint. Except in the case of sexual clothing ot the males, the front and middle tarsi are bare beneath, or armed only with rigid cilise : their structure being thus that characteristic of locomotion on rough surfaces, while in the Hydroporides we have seen the structure of the tarsi indicates an adaptation for locomotion on plants. The male tarsi do not show a great range of variation in the Colymbetides, although very different grades of development of their structure are included in the aggregate. As I have already remarked, the three basal joints of the male front feet are more or less incrassate; in one or two cases (Metronectes, Agabinus), only two basal joints are thus aftected, the third reinaining undeveloped. This increase is in its rudimentary forms but slight, and is an incrassation rather than a dilatation, the increase in the size of the sole for bearing the sexual clothing being obtained by enlarging the diameter of the cylinder in both the horizontal and vertical directions ; in the higher forms it becomes greater, and the incrassation is acconi- 6 G 2 958 On Aquatic Carnivorous Coleoptera or Dytiscidce. panied by a flattening of the joints, such as would be produced by a pi-essure acting on the incrassate cylinder in a vertical direction. These two processes of incrassation and flattening do not go on 'pari passu, some species with much incrassation showino; but little flatteninof, and vice versa. The flatteninsf of the tarsi is carried to its greatest extent in the cases where the individuals are large (gen. Colyrabetes, Meladema), and then the joints are co-adapted, so as to form a saucer-like surface beneath ; but this differentiation never attains the perfection of these parts as seen in Dytiscus, Hydaticini and Cybistrini. The front and middle claws of the males sometimes attain a truly wonderful development, and frequently in such cases are very unequal {vide Lancetes, L. unguioularis ; Agabus, Dytiscus bipustulatus ; Hhantus, Dytiscus exoletus, &c.) The clothing of the under-surface shows great difference in its development ; it is rudimentary and inconspicuous in the lower forms fMetronectes, and several Agabi, &c.), and it may even remain, but littlf developed in species which in other respects have become considerably perfected. In its rudimentary form the clothing is short and uniform, and has the appearance as if some very fine grains of sugar were placed on the under-surface of the foot : in this state I have frequentl}' spoken of it in my descriptions, as " glandular pubescence;" as development becomes perfected, the clothing undergoes both growth and differentiation, the middle hairs have their glandular extremities developed into conspicuous palettes, while the external ones become beautifully elongated into pencils of fine fringing hairs. These de\elopments do not neces- sarily go on pari passu, but the palettes may be greatly developed, with the fringing hairs less perfect, or vice versa ; the greatest development of the palettes may be seen in some Colymbetes (Dytiscus striatus. No. 972,6.9.), while it is in some of the Khanti (I'ytiscus adspersus, and Dytiscus pustulatus for example), that the most perfect fringing hairs are found ; in these cases the extremities of the fringing hairs are beautifully curved. This differentiation into palettes and fringing hairs is not the only one that has occurred in the Colymbetides, for in some of the species of Colymbetes we find that there is {vide D. striatus, &c.) coexistent with these two structures, a basal patch of glandular or cilia-like pubescence ; in such an insect we have a transformation similar to what has occurred in Cybistrini, whei'e the male palettes are surrounded with fringing hairs, and the clothing of the included part of the palette consists of fine hairs on the basal portion and of transverse series of palettes on the outer part. The perfection attained by this structure in the Colymbetides, is however far inferior to what we find in Cybistrini. Gradations in other important parts of the organization are displayed in the Colymbetides ; thus the posterior stigmata, small and almost useless in some of the lower forms, become in Colymbetes transverse, and are the seat of develop- ment of a beautifial minute anatomical structure. As highly exceptional characters exhibited by certain members of the family, the following are worthy of note : a dilatation of some of the intermediate joints of On Aquatic Carnivorous Coleoptera or Dytiscidce. 959 the antenna in Copelatus pulitus ; the display of a file of fine rugte in some of the species of Agabus (group 8) on the tliird venti'al segment ; and the existence of a similar structure on the edge of the second ventral segment in numerous species of Colym betes, and in a few PJianti. The form of the eoxal processes in Agabinus is very peculiar, reminding one somewhat of Noterus. Hydrotrupes and Coptotomus show peculiar labial palpi. A.nd in Platambus we have a remarkable increase in the posterior portion of the epipleur*, which however is approximated by certain Agabi. In Matus we have a conspicuous sulcation of the presternum which is repro- duced in Spencerhydrus, a genus of Cybistrini. While in several genera (A.gametrus, Metronectes, and others) we have the very exceptional occurrence of a complete efFacement of the coxal lines. Colymbetes reticulatus, (Laucetes) shows a difference in the colour of the ventral segments of the two sexes, similar to what exists in certain species of Bidessus and Coelambus, in the Hydroporides. The interesting Madeiran species of Meladema, (Dytiscus lanio) makes an approach to the genus Dytiscus in several respects, and it has the suture on the front of the head distinct as is the case in that genus, and the clypeus is coloured yellow as in that genus, while the two pale marks on its vertex seem to indicate the manner in which the angular mark on the front of the head of Dytiscus has been developed from the two pale spots so common in the Colymbetides. As regards geographical distribution little can be said, except that the great majority of Colymbetides are inhabitants of the northern parts of the Eastern and Western Hemispheres, but one large genus (Copelatus) is on the contrary chiefly tropical. TIL 4.— Tribe HYDATICIDES. {Vide p. 647.) This tertiary aggregate consists of about one hundred species arranged in five primary aggregates, plus three isolated species ; and in the second synthesis these are reduced to two aggregates, plus an isolated primary aggregate. They are all insects of moderately large size — one-third of an inch to two-thirds of an inch in length : the colour of the surface is generally variegate. The head is short, the eyes are large, the insertion of the antenna is but little protected by the side of the front, and this does not infringe on the circular outline of the eye ; the frontal suture can be detected only at each side ; the antenna are elongate and slender but to a variable degree. The hind coxae are large, and the wing of the metasternum has always a slender sub-parallel deflexed band as its terminal portion ; this band is however very variable in its length according to the amount of forward extension of the hind coxa. The coxal lines are always short, (sometimes quite obliterated) and in front they are very far indeed from attaining the front border of the coxa ; the coxal lobes are never elongate and are always broad in proportion to their length, and when the 960 Qn Aut as I am about to dilate on this elsewhere, it is here only necessary for m^ 2 B c X Q 2 5 ■i^ -^ i -; -^ >, ^ >^ ^ ct X > ^^ O -T o :r ^ |1 ^ 0) C 2 'w iCfi^ C5 X H II II II II II II II II M W X X r/7 rr rr rf> c o o ^ C c O CC 02 o o o o o o (D OJ 0; C O O Ch &. CI, =u ;i, =:. a2 cc a; aj oi 03 -a — _c s: ?; — < B f^ C C s' ai X V. X X !r. oj o) ii ,2 "^ .£ *o 'o '3 '^ 'il "o 0) a; a; c c a, cu ;x, C- ;i^ — z. ? C .^ ^ 5 » CO r ^'::r ^ <^ £ c l-s bJ § ? i o +j '-r ^ o :r i- 2 II O fC 5 i £ 1 2 ^ g Z > ^PhSoq-^^ ^ o,X x -ji x/1 'Ji x -Ji m xr. tfi tfi .S .i .^ .-^ .^ .^ "^ "^ -' ® "S *o 'o '3 *5 *3 'C '3 'o '3 CC C"" ^ e s s £ 5 5 ^ r^ 't a; X o in o On Aquatic Carnirorom Coleoptera or D/jtiscidce. S77 A.SS1FICATI0N. •3 g P a o CO Q h- 1 m >^ o O o 1—1 K S E- a w c o X K O s 2 g ^ = I H ^- -5 -^ -1 O -£ O q SB 02 CO a: a; o g d s 3 Is as II II II II II M x M x 3: O -J 1) ai c; o -J y :j u :a a c; C) rjj X GO CC X >o IM O CO C-l '^ rt K;i; p^; ^ -M ;: i: ;: ; H a -i :; f O O O U i> o cj o :;; :^ c; (U XX XX XXX XXX ^ "^ ■'^ ^T u ^ :s X X S S Q 3J a; O" ^ :j O :.j ij V X X X X CC c^ ••S: CO 978 EXPLANATION OF ABBREVIATIONS OF AUTHORS' NAMES AND TITLKS OF WORKS CITED. Aube, Ic. v., . • • Aube, Sjiec, ■ Bab., Tr. Ent. Soc. Lond., Ballion, Bull. Mosc, , Bert., Bull Ent. It., Bluncli., Von. Pole Sud., Boh., Ewjeii. lies., . . Boh., Ins. Caff'. /., . . • Borre, Ann. Soc. Belg. XIV., . Brulle, Exp. 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Coleoptera Atlautidum. London, 1865. Wollaston, T. V. Colcoi)tera hesjieridum. London, 18G7. , Wollaston, T. V., in the Transactions of the Entomological Society of London, 1871. . Zetter.stedt, J. W. Fauna insectorum Lapponicfe. Hammone, 1828. . Zoubkoff, B., in Bulletin de la Societe imperiale des naturalistes de Moscou. Vol. VI. Moscow, 1833. 983 EXPLANATION OF PLATES. PLATE VII. Fig. 1. Uppersui'face of head of Cy bister (Dytiscus rceselii, Fab.) Fig. 2. Undersurface of head of Cybister (Dytiscus roeselii, Fab.); a, intiexed angle of epicranium, bearing the antennal cavity ; h, eye ; c, maxillary cleft ; d, gula ; e, sutui'e between proto- cranium and epicranium. (The artist iu endeavouring to make the drawing of this figure look less diagramatic has diminished its anatomical value ; the curved line extending across the front of gula, and also the second transverse line behind the eye, indicate not sutures but merely depressions of the surface). Fig. 3. Anterior portion of body of Pelobius : (after Regimbart). Fig. 4. Anterior jiortion of bod}' of the DytisfidiV : (after Regimbart). Fig. 5. Inner face of labruni of Dytiscus (D. marginalis, L.), after Schiodte, Dan, EL, Table XXI, c. ; (.showing conical prominences and commencement of oesophageal membrane). Fig. 6. Right mandible of Dytiscus (D. marginalis, L.), after Scliiijdte, Dan, EL, Table XXI, a, b. ; «, upper face ; b, under face. Fig. 7. Left maxilla of Dytiscus (D. marginalis, L.), ,, ,, ,, Cj d ; the ritjht liand fig. is as seen from beneath ; the left hand fig. as seen from above, with maxillary fringe omitted ; a, leathery basal portion of inner lobe ; /3, squama ; y, stipes ' d, hollow for paljius : (in these figs, the e.xtremity of the inner lobe should be more abniptly curved). Fig. 8. Labium (outer face) of Dytiscus (D. marginalis, L.), after Schiodte Dan., El., Tab. XXI, f. ; (in this fig. the .supports of the labial palpi should be emarginate). Fig. 9. Labium (outer face) of Cybister (D. rceselii, Fab.) Fig. 10. Labium of Dytiscus (D. marginalis, L.), after Schiodte Dan., El. XXI, g. h. Right-hand fig., inner face, a, resopliageal piece uniting by a curve with its fellow of opposite side ; j3, fulcrum or siijiport ; y, stijjps or .stem ; J, paraglossa. Left-hand fig., right side of ligula, removed with labial pal] ms, and seen externally; a, (Esophageal piece; /3, fulcrum; y, stipes, (this and the precoiling seen without cilia') ; B, support of palpus ; c, membranous piece connecting y and c ; J, paraglossa. Fig. 11. Antenna of Cybister (D. rceselii). Fig. 12. Antenna of Hydrovatus aristidis $. Fig. 1 3. Antenna of Noterus Isevis $ (after ISIigneaux, the joints are rather too elijngate). Fig. 14. Lateral aspect of undersurface of pi-othor.ox of Cybister (D. roeselii) ; a, medisternum ; b, prosternal process ; c, epistemum ; d, epimeron ; e. inflexed portion of pronotum ; ,/, depres- sion for reception of front coxa. Fig. 15. Lateral aspect of undersurface of prothorax of Hyphydrus (Dytiscus ovatus, L.), lettering as in Fig. 14. Fig. IG. ^riddle of prosteruum of Hyphydrus (Dytiscus ovatus, L.); a, medisternum ; b, prosternal process; c, coxal depression. Fig. 17. Prosternal process of Hydrocanthus, (H. atripennis). 984 On Aquutic Corjiirorous Coleoptera or DijtisciiUn. Fig. 18. Pi-ostPi-nal process of C:mtliy(lni-;, (C. gniininicus). Fig. 19. Prosternal pi-ocoss of Hyclrovatus. Fig. 20. Prosternal process of Platj-nectes. Fig. 21. Prosternal process of Neptostenius. Fig. 22. Prostenial process of LaccopLilus (D}tiscus maculosus, Geim.) Fig. 23. Mesostcnmin of Dytiscus (D. niargiiialis, L.) ; a, episteruum ; b, epimeron ; c, portion of margin of iniiliUe coxal caA'ity ; '/, iiiedisternum. Fig. 2-t. Mesostcrnum of Hyilroeantluis (H. atripennis), one side removed ; lettering as in fig. 23. Fi". 25. Middle coxal cavity looked into, and seen laterally, of Eretes ; a, mesosternum ; h, metaster- num ; c, vacant space forming a foramen of comnumication with tlie cavity of otlier side of body. Fig. 2G. Same parts in Hydaticus rimosus. Fig. 27. Same parts in Dei-onectcs (DytLscus assimilis, Payk.) Fig. 28. Same pai-ts in Deronectes (Hydroporus luctuosus, Aube). Fig. 29. Same parts in Hvdroportis (Hypliydrus memnonius, Nic.) Fig. 30. Diagram of pieces surrouudinj; middle coxal cavity in Hydrocantlius (Dytisci fragmentali) ; a, mesosternum (medisternuin) ; h, its cpisternnm ; c, its epimeron ; d, episternnm of meta- sternum, with exposed and thickened anterior margin simulating an additional piece ; e. metastemum ; f, coxal cavity. Fig. 31. Similar diagram of Laccophilus (also Dytisci fragmenti). Fig. 32. Similar diagram of Colymbetes (Dytisci comj)licati), but with epipleura represented ; a, meso- sternum ; h, its episteruum ; c, epijileura ; (/, metathoracic episternnm with incrassate and exposed anterior liortler; e, inetasternum ; f, coxal cavity; g, mesothoracic epimeron. Fig. 33. Diagram of the middle of undersurface in Silphomorpha (Carabidoe, Pseudomorphini) ; a, meso- sternum [)roper (medisternum) ; h, its e]usternum ; c, its ejiimeron ; d, metasternum ; e, its episteinum ; f, its epimeron ; (j, internal lamina of hind coxa ; /(, external lamina of hind coxa ; i, first ventral segment ; /•, middle coxal cavity. Fig. 3-1. Diagram of same parts in Procrustes (Carabida?, Carabini) ; in tliis the parts of the side pieces usually covered by the wingcases are introduced ; and f, indicates the external portion of the metathoracic episternum to which the membranous epimeron is attached, the suture between these two pieces being really placed on the inner face of tlie episternum and thus concealed : otherwise lettei'ing as in fig. 33. Fig. 35, Diagram of same parts in Cybister (Dytiscus rceselii) ; the lateral portions are covered by the wingcase when this is closed ; letterii^g as in fig. 33. Fig. 36. Metasternum and hind coxa; of Ampliizoa. Fig. 37. Idem „ Pelobius. Fig. 38. Idem „ Suphis. Fig. 39. Idem „ Noterus. Fig. 40. Idem „ Hydrovatus. Fig. 41. Idem „ Queda. Fig. 42. Idem „ Laccophilus. Fig. 43. Idem „ Hyphydrus, on the right side of this figure, the first ventral segment, and the external parts [of the pieces usually concealed by the wingcase are introduced. Fig. 44. Metasternum and hind coxa; of Methles. Fig. 46. One side of metastemum'and hind coxa of Coelambus. Fig. 46. Hind coxa of Hydroporrs. Fi;;. 47. Idtfii of Paroster. Fig. 49. Idem, Fig. 50. Idem Fig. 61. Ideia Fig. 52. Idem Fig. 53. Idem Fig. 54. Idem Fig. 55. Idem On Aquatic Carnivorous Coleoptera or. Di/tiscidce. 985 Fig. 48. Internal laminie of liiml coxre of Hydroporus diver.siconii.s. „ Hydroporus oblongus. „ Agabiis (Dyfciscus bnmneus). „ Agabus (Dytiscus bipustiilatus). „ Platambus (Dyliiscus maculatu.s). ,, Agabiuus. „ Copelatus. „ Agabetes. Fig. 56. External lamina and wing of mctasteniiun of Agabus (Dytiscus uliginosus). Fig. 67. „ „ „ Agabus (Dytiscus abbreviatus). Fig. 58. „ ,, „ Platambus (Dytiscus maculatus). Fig. 59. „ „ „ Copelatus. Fig. GO. Hind coxa and one side of metasteruum of Prodaticus. Fig. 61. „ „ „ Hydaticus. Fig. 62. „ „ „ Thermonectes. Fig. 63. „ „ „ Acilius. Fig. 64. „ „ „ Eretes. PLATE VIII. Fig. 65 Lateral view of articulations at side of breast of Eretes ; n, metatlioracic episternum ; b, meta- tlioracic epimeron ; r, 1st ventral segment; d, bind coxa; e, wing of metasternum : in thi.s fig. and in fig. 66, the portion on the left of the dotted line is covered by the wing-case in the condition of repose. Fig. 66. Lateral view of articulations at side of Ijreast of Cybister (Dytiscus roeselii, Fab.) ; lettering as in preceding fig. Fig. 67. Ventral segments of Dytiscus (D. marginalis.) Fig. 68. Idem ,, Pelobius (Dytiscus tardus.) Fig. 69. Dorsal aspect of middle and hind body of Cybister (Dytiscus roeselii, Fab.), with the left wing- case and wing removed ; a, right wing-case ; b, scutellum ; c, mesonotum ; (/, point of articu- lation of wing-case : e, angle of mesothoracic episternum ; f, upper edge of mesothoracic epimeron ; tj, upper (semicorneous) portion of metathoracic episternum ; /;, idem of metatlio- racic epimeron ; i, line of attachment of wing ; k, jiieces of metanotum ; I, trochanter of articulation between various pieces; ///, hind border of metanotum, where is situate the metathoracic breathing aperture ; 1 to 8, dorsal plates of hind-body or abdomen ; 1* to 6*, upper edges of ventral plates of hind-body ; s to s', abdominal stigmata or breathing apertures. Fig. 70. Superior oblique lateral view of i-ight side of hind-body, and metasterno-coxal articulation of Dytiscus latissimus ; a, portions of metanotum ; b, metathoiacic epimeron ; c, angle of hind- coxa ; (/, metathoracic stigma ; e, side j^iece of fii'st ventral segment ; /', stigmatic rugte ; g, fii-st abdominal stigma ; 1 to 8, dorsal plates of hind-body : this diagram is made from a specimen distended by stufiing with cotton-wool, so that the membranous portions are shown as fully as the corneous. Fig. 71. Outline of front foot of Hyphydrus $, (Dytiscus ovatus, L.) Fig. 72. Outline of front foot of Hydroporus S- Fig. 73. Outline of front foot of Necterosoma. Fig. 74. Anterior tibia and tarsus of Noterus ^ (after Sohiodte, Dan. El. XVIII, A), 986 On Aquatic Carnivorous Coleoptera or Vijtiscida. Fig. 75. Anterior tai-sus seen laterally of Xoterus f (after ScLiodte, Dan. El. XVIII, i). Fig. 76. Under sui-t:ice of front tarsus $ of Laccophilus (after Scliiudte, Dan. El. XVIII., t). Fig. 77. Front tarsus $ of Agalnis (Dytiscus chalconotus), (after Schiodte, Dan. El. XIX, a*). Fig. 78. Upper surface of front tarsus of J'^retes $. Fig. 79. Under surface „ idem. Fig. 80. Kight front tibia and tarsus of Eretes $. Fig. 81. Intermediate leg of Cyliister $ (Dj-tiscus rojselii). Fig. 82. Hind or swimming leg of Hyckovatus. Fig. 83. „ „ Macroportts (lower face, the cilise are repi-esented abbreviated). Fi". 84. „ ,, Hydrocantlius atripennis (upper face). Fig. 85. „ „ Megadytes (lower face, Cybister giganteus $). Fig. 86. Hind tarsus (without ciliie), of Pelobius; a, sole; b, the short side. Fig. 87. ,, ., Scutopterus horni. Fig. 88. • ,, „ ' Hyderodes shuckhardi. Fig. 89. ,, ,, Laccophilus. Fig. 90. ,, ,, Sandracottus (S. huntei-i). Fif. 91. ,. „ Cybister (Dytiscus rccselii. Fab.) Fig. 92. Terminal joint of hind tarsus with claws of Homceodytes. Fig. 93. ,, „ „ Cybister (Dytiscus immarginatus). Fig. 94. „ „ Megadytes ^f. Fig. 95. Epipleura of Chostonectes. Fig. 96. Wing of DytLscus sidcatus (Acilius) ; a and h, costal and subcostal nervures ; c, median nervnre ; d, submedian nervure ; e, anal ncrvure ; /, carpal cell, or carpa ; g, jngraent fleck. Fig. 97. Wing of Hydaticus flavo-lineatus. Fig. 98. „ of Cybister, (Dytiscus roeselii, Fab). Fig. 99. Dorsal and lateral aspect of cedeagus of Cybister confusus. Fig. 100. Idem „ ,, of the closely allied Dytiscus limbatus (the lower portion is not sufficiently elongate in this figure). Fig. 101. Idem of Cybister guerinii. Fig. 102. Idem of Dytiscus trij)unctatus (Cybister) ; (the rendering of the dorsal aspect is not exact, but its outline is fairly coi-rect.) Fig. 103. Doi-sal, lateral, and ventral aspects of cedeagus of Dytiscus roeselii. Fab. (Cybister). Fig. 104. Dorsal and lateral aspects of cedeagus of Dytiscus latissimus (Dytiscus). Fig. 105. Lateral aspect of ojdeagus of DytLscus sticticus (Eretes) on same scale as preceding figs. PLATES IX TO XVIII. These Plates represezit figures of one or more species of each genus of the Dytiscidie ; as the figures are all numbered, and the numbers with the names are given at the foot of each plate, it is not necessary to repeat the names here. INDEX This index contains an alphabetical reference to the species descriptions included in the previous IVlemoir, and also a set of references to complete a connection between the noTnenclature of the Munich Catalogue of Coleoptera, of Anbe's Species generate des Hydrocanthares, and that of this Memoir. It also includes certain other synonyms, such as some of date subsequent to the Munich Catalogue, i|ualis, Horn. Colymbetes iusolutus, Avdie =: Colymbetes interclusus, Walk. Colymbetes in-oratus, Brulle =r Colymbetes lanceolatus . Colymlietes lanio, Aiibii = Colymbetes lateralis, Gebl. Colymbetes latus, Fairm, nee. Geb. = Colymbetes latus, CtoIiI. . Colymbetes limbatus Colymbetes liiieatus (-'ol^'mbetes lineatus, IJedt. 1210 708 1211 1212 1213 939 890 924 1214 907 121.5 757 121G 93.5 972 942 957 9.56 1217 951 924 953 978 1218 905 9G0 1219 968 1220 1221 1222 1223 930 1037 1224 1225 73fi 966 1226 1227 1228 961 973 773 777 879 1229 943 967 1230 1231 1233 1232 951 1234 926 913 979 1235 958 1236 941 856 1237 Colymbetes loiigulus Colymbetes m;iculicipllis, Aube = Colymbetes magellauicus, Bab. Colymbetes marmoratus Colymbetes marmoratus, Perr. Colymbetes mexicanus . Colymbetes uioiiostigma, Hope Colymbetes montrouzieri, Luc. := Colymlietes iiigiicejis Colymbetes iiitidus Colymlietes notaticollis . Colymbetes uotatus, Aube = Colymbetes obscuricollis, Aube Colymbetes obtusatus Colymbetes octodecimmaculatus Colymbetes pacificus Colymbetes parvulus Colymbetes pa^kulli Colymbetes peruvianus . Colymlietes jtlijeopterus, Kiib. Colymbetes piceus Colymbetes picipes, Kirli. Colymbetes procerus Colymbetes pneniorsus . Colymlietes pulcber Colymbetes jjulverosus . Colymbetes pustulatus, Aube = Colymbetes quadriguttatus Colymbetes reticulatus, Kirb. =: Colymbetes rotundicollis, Bab. Colymbetes ruficeps, Jleu. Colymbetes rugipeuuis . Coh'mbetes sculptilis Colymbetes semuiiger C'oh'mbetes semipunctatus Colymlietes seriatus Colymbetes signatus, Griunn. Colymbet&s simplex, Walk. Colymbetes sinuatus Colymbetes sobrinus, Motsch. Colj-mbetes socialis, Waterh. Col^-mbetes staguinus Cohmbetos striatus, Aube = Colymbetes strigatus Colymbetes strigipemiis . Colymbetes strigosus, Lee. Colymbetes sulimaculatus, Cast. Colymlietes sulxpiadratus, Motscli, Colymbetes substrigatus Coh mbetes sulcipenuis . Coh-mbetes suturalis, Macl. Colymbetes thomsoni Colymbetes tseuiolatus Colymbetes tostus Colymbetes trilinoatus, Aube = Colymbetes trivittatus, jMontr. Colymbetes truucatipennis, Miin, Colj'mbetes ungularis, Lee. Colymbetes vagaus Colymbetes vibicicollis, Hoch. Colymbetes viciuus COLYMUETIDES COLYMBETIKI COPELATU.S Macl. (V. p. 973) Cat. 962 935 1238 10G9 1239 936 1240 924 915 940 946 947 1241 685 124? 920 821 961 776 1243 975 1244 977 916 1038 924 945 7S2 736 1245 1246 969 968 963 695 673 1247 1248 944 1249 1250 689 973 964 894 1251 1252 1253 974 895 1254 970 701 950 926 1255 1205 1256 976 1257 928 956 934 892 Index. 991 ■Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus -Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Co])elatus Copelatus Copelatus Copelatus Copelatus Copelatus Cop'jlatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Cojielatus Copelatus Co))elatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Cojielatus Copelatus Copelatus Copelatus Copelatus Copelatus Copelatus Cojielatus Ch acuductus ad \'eua africanus alternatus angustatus ater atriceps aubei . australia?, C\\ liadeni basalis, Boh. bicolor, Muu. boiivouloiri brullei buqueti cajlatipeunis capeusis carinatus clievrolati clarki . censors concolor coxalis daeuieli decemstriatus, debilis depressus dimorphus discoideus distiuctus dori:i3 . duodecimstrif dupouti elongatuluS; ericlisoui exaratus exteiisus externus, ferruginous filifoi'niis fonuosus, Woll fuscipennis gallapagoensis, geniculatus geutilis glypliicus, i\]u gracilis guerini liydroporoides impressicollis indicus innjqualis inornatus insolitus integer iuterruptus irregularis labratus latipes lineatus, Mun, lividus lougicornis maculatus margiuatus melanarius Kir Cat. Aube = atus Macl. sell Waterh. .. Cat. = Cat. = 819 880 863 84.3 12.58 SU 826 896 12.59 887 1260 1286 84.5 891 884 883 848 868 865 867. 840 842 836 888 879 8.50 877 827 861 882 849 837 844 1261 873 885 815 1262 810 805 1263 855 1264 858 857 879 808 835 807 878 860 838 824 823 881 847 890 812 853 85 G 811 828 816 851 817 Copelatus niundus Copelatus neglectus Copelatus nigricans Copelatus nigritiilus Copelatus nigro-lineatus . C!opelatus nitidus Copelatus normalis, Er. . Copelatus obertburi Copelatus oblitus Copelatus obscunis Copelatus obtusus, Boli. . C'opelatus perfectus Copelatus peruvianus, Muu. Cat. Copelatus politus Copelatus jiolystrigns Copelatus posticatiis, Mun. Cat. Copelatus prolixus Co]ielat>is jirolongatus Copelatus pulcbellus, Mun. Cat. Cojielatus punctulatus Copelatus punctulatus, Aube = Copelatus pusillus Copelatus quadrisignatus, Eegt. Copelatus restrictus Copelatus rufipes Copelatus sexstriatus Copelatus signatus, Sharp ^ Copelatus simplex Copelatus striatellus, Boh. Copelatus striaticollis, Luc. Copelatus striatopterus . Copelatus striatulus Copelatus strigulosus Copelatus subjectus Copelatus substriat\is, Kirscli. Copelatus sulcatus Copelatus sulcipennis, Mun. Cat Copelatus terminalis Ciipelatus tibialis Copelatus undecinistriatus, Aube Copelatus validus Copelatus victoriaj Copelatus vigintistriatus COPTOTOMUS Coptotomus difficilis, Lee. Coptotomus interrogatus, Mnn. Cat. Coptotomus longulus Coptotomus obscurus Coptotomus serripalpus, Say. Cybister Cybister wneus, Orm. Cybister artensis, Montr. = Cybister asiaticus Cybister auritus, Gerst. . Cybister bcngalensis Cybister biniac\ilatus, Aube =: Cybister binotatus Cybister Viisignatus, Aube =: Cybister bivulnerus, Aube =: Cybister brevis . Cybister buqueti Cybister celebensis Cybister cephalotes CyViister cliaudoiri, Hoeli. ^ Cybister chinensis P- P- 839 841 870 818 846 834 1205 893 859 874 1266 S89 776 822 Sl-l 875 832 S69 864 831 879 854 1267 829 897 830 875 813 12G8 1209- 892 852 862 820 1270 886 895 876 833 1271 866 800 871 896 1272 yii 912 910 1273 918 1274 1140 1142 1275 1159 11.35 1133 1122 1133 1128 1154 1166 1153 1169 1162 992 On Aquatic Carnivoivud Lohoptera or Dytiscidai. Cybister cinctus . (-y bister cognatus Cybister coufusxis (^ybister convexus Cybister costalis ■ (Jyliister crassipes CybistiT crassiis Cybister deliaani , Cybister dejeani, AuIjc . Cybister tlei>laiiatiis Cybister desjardinsii, AwbS = Cybister dissiuiilis, Aube = (/vbister distiuctus Cybister dytiscoides Cybister ellipticus CvV)ister exj)lanatus Cybister fallax . ( Vbister tilicoruis Cybister fiavoeinetus Cybister fumatus C\ bister gayndahensis, Macl. = Cybister giganteiis Cybister glaiicus Cybister godeffroyi Cybister goi-yi, Aiibe Cybister gotscLii, Hocli. ^ Cybister gracilis Cybister giieriiii Cybister hnokeri Cybister iminargiuatus . Cybister indic\is, Aube = Cybister iusignis Cybister insularis, Hope Cybister irritaus Cybister japoniciis Cybister javanus Cybister jordanis, Reielie Cybister lewisianus Cybister I'lierniinieri, Cast. = Cybister madagascariensis, Aube Cj'bister marginicollis, Boh. Cj'bister niodestus Cybister nigripes Cybister notasicus, Aube = Cybister novre-caledonise, Montr. Cybister occidentalis Cybister olivaceus, Boh. = Cybister olivieri, Crotch Cybistytiscus pictus . 648 Dytiscus pisanus 992 Dytiscus planus . 675 Dytiscus posticatus 875 Dytiscus punctulatus 983 Dytiseus pustulatus 945 Dytiseus i-eticulatus, Fab. = 386 Dytiscus -rceselii . 116» Dytiscus rufieollis. Fab. = , im» Dytiscus rufifrons 615 Dytiscus seminiger 1006 Dytiscus seijtpntrionalis, Aub6 ^ 1003 Dytiseus serricornis 755 Dytiscus sharpi . 98i Dytiscus signatus 926 Dytiscus-stagnalis 1011 Dytiseus sticticus 1095 Dytiscus striatus . . 972 Dytiseus striolatus 710 Dytiscus- sturmi . 737 Dytiscus sublimbatus , , 990 Dytiscus. snlcatus 1052 Dytiseus tardus . 1 994 On Aquatic Carnivorous Coleoptera or Dijiiscida.'. Dytiscus tataricus, Gel>l. Dytiscus trans veraal is Dytiscus tripuuctatus Dytiscus tiistis . Dytiscus uliginosus Dytiscus uuifasciatus, Fab. Dytiscus unistriatus Dytiscus variegatus DytLscus veri-ucifcr Dytiscus versicdlor Dytiscus verticalis Dytiscus vexatus D_vtiscus vittatus Dytiscus vittiger Dytiscus wasastjei'UiB Dytiscus zonatus Eretes . Eretes australis . Erigleuus uuguicularis, Tli. = Eunectes australis, Muu. Cai. - Eunectes conicollis, Woll. = Eunectes griseus, AuVie = Eunectes helvolus, Klug. = Eunectes occidentalis, Er. = Eunectes jiunctatus, Zoub. =: Eunectes punctipcnnis, Macl. = Eunectes sticticus, Muu. Cat. ^ Eunectes subcoriaocus, Woll. ^= Eunectes subdiaplianus, Woll. = Eunectes succinctus, Kl. = Gaurodytes wueolus, Or. = Gaurodytes angusticollis, Sahl. Gaurodytes biguttulus, 'J'b. =^ Gaurodytes boreellus, Said. := Gaurodytes clypcalis, Tb. = Gaurodytes coriaceus, 8abl. = Gaurodytes disintegratus, Crotcb =; Gaurodytes dissimilis, Sabl. = . Gaurodytes inscriptus, Crotch = Gaurodytes intersectvis, Crotch = Gaurodytes lecontei, Crotch = Gaurodytes leptapsis, Lee. Gaurodytes longulus, Lee. Gaiirodj'tes lutosus, Crotcb Gaui-odytes minimi, Sahl. = Gaurodytes obovatus, Sabl. Gaui'odytes obscuri]iennis, Sahl. Gaurodytes ovalis, Sahl. Gaurodytes ovoideus. Crotch := . Gaurodytes septemseriatus, Sahl. := Gaurodytes strigulosus, Ci'otch = Gaurodytes suturalis, Crotch Gaurodytes thomsoni, Sabl. ^= . Gaui-odytes walslnghami. Crotch := Gaurodytes zetterstedti, Th. = Graphoderes Grapboderes elatus Grajiboderes porplcxus . Gra]iboderes piciycntris . Herophydrus , Heroi)bydrus li'2i;os Horopbydrus ol)!jcui-us , Herojibydrus oscillator , 129.-) 1012 11 40 C02 G'J-t 129G 2G1 155 1002 386 988 997 1049 741 720 1091 913 1096 700 109G 1095 1095 1095 1095 1095 1095 1095 1095 1095 1095 696 1297 697 097 712 70G 702 707 706 067 731 r:98 1299 1300 721 1301 1302 1303 724 670 717 1304 700 723 733 .. 912 1090 1089 1093 : 801 375 379 380 HeriH)bydrus verticalis . He>oj)liydrus spadiceus . Heterhydrus . Heterbjdrus agaboides, Fairm. = HOJKEODYTES, HrXELHYDRl'S . Huxelbydrus syntheticus Hyd.vticides hvdaticixi hvdaticus Hydaticus adamsii Hydaticus agaboides Hydaticus aniazouicus . Hj-daticus amci'icanus Hydaticus aj)icalis, Boh. Hydaticus aruspex, Clk. Hydaticus austriacus Hydaticus bacri, l^egt. . Hydaticus Ijakcwelli Hydaticus bibaiuatus Hydaticus biliueatus, Aube = Hydaticus biuiarginatus, Aube = Hydaticus bipunctatus, Wehncke Hj'daticus bivittatus Hydaticus bowringi Hydaticus brunnipennis, Aulie Hydaticus cafter, Boh. . Hydaticus capicola Hydaticus chevrolati, Aube = Hydaticus cinctipeunis . Hydaticus cinereus, Aub6 = Hydaticus concolor Hydaticus congestus, Klug Hydaticus cousanguineus Hydaticus daenieli Hydaticus decoius Hydaticus dejeani Hydaticus dineutoides . Hydaticus discoidalis, Hope Hydaticus disci n dens, Walk. = Hydaticus dorsiger HydaticiLS drcgci Hydaticus du]ile.x Hydaticus exclamationis Hydaticus fabricLi . Hydaticus fasciatocollis, Mun. Cat. Hydaticus fasciatus, Mun. Cat. ^ Hydaticius festivus, Aube ^ Hydaticus flavocinctus, Mun. Cat. Hydaticus flavolineatus . Hydaticus fractifer. Walk. = Hydaticus fulvonotatus, Clk. Hydaticus fusci\eutris, Reiche H^'daticus galla . Hydaticus goryi . Hydaticus gi-auimicus, Mun. Cat. Hydaticus histrio, Clk. . Hydaticus hybncri, Aube = Hydaticus incaustus, Aube == H\'daticus insiguis Hydaticus isabelli, Aube = Hydaticus Japonicus, Sharp = Hydaticus jucundus 376 377 850 223 916 854 326 959 939 907 1087 1034 1018 1009 1305 1306 1085 1307 1077 1021 1094 ■ 1015 104!> 1045 1048 1084 1308 1043 1073 1008 1088 1031 1309 1037 1044 1025 1075 1023 1310 1021 1029 1027 1047 1050 1035 1086 1073 1074 1290 1024 1021 1311 1032 1042 1020 1028 1312 1006 1040 1076 1040 1087 1026 Index. 995 Hyt-laticus Iwvipenuis Hydaticus lateralis, Cast. Hydaticus leander, A\ibe = H3'daticus leveillei, Regt. = Hydaticus liber, Mun. Cat. ^ Hydaticvis luczonicus Hydaticus maeulatus H3'daticus madagascariensis, Aube Hydaticus marnioratus, Aube = Hydaticus matruelis Hydaticus mixtus, Blauchd. = Hydaticus modestus Hydaticus nauzieli, Fairm. Hydaticus iiigro-marnioratus, Clk. Hydaticus iiigrovittatus, Clk. Hydaticus pacificus, Aube = Hydaticus paganus, Clk. Hydaticus palliatus Hydaticus parallelus Hydaticus petitii Hydaticus philiiipeusis, Welin. Hydaticus piceus Hydaticus pouticus Hydaticus punctipennis, Th. = Hydaticus reotangulus . Hydaticus rectus Hydaticus rhantoides Hydaticus rielili, Welm. Hydaticus rimosus Hydaticus rochasi, Montr. = Hydaticus ruticollis, JNIun. Cat. =: Hydaticus rufulus, Aube = H3'daticus seminiger, Mun. Cat. Hydaticus servillianus . Hydaticus signatipeunis . Hydaticus sobrinus Hydaticus stagualis, Aube = Hydaticus suljfasciatus . Hydaticus transversalis, Aube = Hydaticus unifasciatus, Mun. Cat. Hydaticus usberi, Clk. . Hydaticus variegatus Hydaticus verecuudus, Clk. Hydaticus vittatus, Aube = Hydaticus xantlunnelas, Brulle H3'daticu« zonatus, Aube = Hyderodes H3'derodes collaris Hj'dei'odes crassus H\Hlerodes shuckhardi . H3draclina australasise, Mun. Cat. H3'dracLna nigra, Mun. Cat. ^ Hydraclma tarda, M>m. Cat. =: Hydroc^ntuini Hydrocanthus . Hydrocanthus advena Hydrocanthus asperatus Hydrocanthus atripennis Hydrocanthus auiitus, Regt. Hj'drocanthus australasise Hydrocanthus badenii, Wehncke ^ Hydrocanthus buqueti, Mun. Cat. = Hydrocanthus debilis Hydrocanthus deyrollei . TIIA>S. HOT. DCB. SOC , U.S. TOL. IL 1010 1313 1032 131^ 1084 1022 1082 1314 1069 1030 1073 1007 131.5 131C 1317 1021 1318 1040 1014 1001 1319 1013 1033 1012 104(5 1017 1036 1320 lOlG 1083 1020 103.5 lOOG 1039 1083 1041 1011 1019 1012 i29t; 1321 1063 1322 1049 1323 1091 903 982 981 980 2 3 1 920 839 80 18 77 1324 71 55 42 78 82 Hydrocanthus fasciatus, Steinl. Hydrocanthus flaviis Hydrocanthus funebris . Hydrocantlius grandis, Mun. Cat. Hydrocanthus guttula H3Mlrocanthus haagi Hydrocantlius indicus H3'drocanthus iricolor H\drocanthus l;evigatus, Mun. Cat. = H3'drocantluis lineatus, VVehn. Hydrocanthus luctuosus H3lius flaviculus, Motsch. Hy'dropeplus Hydroporomorpha parallela, Bab. Hydroporides . Hydroporini Hydroporus Hydi-oporus aberrans, Clk. Hydroporus acaroides H3'droporus acumiiiatellus, Fairm. H3-droporus acuta.ngulus Hydroporus addendus Hydroporus adumbratus, Clk. H3'droporas advena H3-droporus sequinoctialis H3-droi)orus atiinis H3'droporus alienus, Sharp = Hydroporus alpinus, Mun. Cat. Hydroporus alticola H3'droporus ania\)ilis Hydi'oporus amaudus, Lee. Hydroporus americanus . Hydroporus analis Hydroporus angularis, Klug. Hydroporus angulipennis, Peyr. Hydroporus angustatus . H3'dro}iorus anticus Hydroporus antidotus Hydroporus apicatus 1325 70 79 81 54 G8 72 74 76 1326 CO 57 1327 47 55 73 62 69 64 1328 19 52 1329 39 1330 73 63 834 12 1331 1332 1333 1334 11 8 10 1335 855 1336 950 928 868 1337 389 489 596 523 1338 649 525 318 533 529 590 293 1339 619 579 1340 1341 605 509 572 244 e M i)a?ticus l>ake\vel]i, Clk. basal is basiuotatus, Reiclie belfragei bioariuatus bicostatus bifasiiatus, Macl. bitidus, Say. bihamatus, Cliev. = bilineatus bivittis, Mun. Cat. ^ bistrigatus blakci bombyciiius bonarieusis, Steiul. boiuiaii'c'i, Fairm = boristlieuicus, Hoch. braunani, Scliauf. = bnivis brucki bnmneipeuuis, Macl bi'yaiistoui . caligiuosus, Lee. caualiculatus cant.iliricus caraibus carboiiarius, Clk. carinaius c;isj)ius celatus ceresyi charlotti, Clk. chilecsis cimicoides . ciuctellus clarki cleopatra;, Poyr. clypealis collaris collaris, Boh. =: collaris, Hope compactus . compunctus. Woll. conciuuus confluens, Mun. Cat confusus coiifusus, Luc =. conicus conoideus, Lee. = consiniilis contractulus, Mann. eonvexus eopelatoides . coquerelii, Fairm. C28 Hydroponis corpulentus 411 471 Hydroporus corsicus 5(i5 589 Hjdroporus costipenuis . 251 1342 Hydroporus cribratellus, Fairni. 1356 598 Hydroporus cribrosus 242 495 Hydroporus crotchi 477 GIO Hydroporus crux, Mun. Cat. = . 549 026 Hychoporus cuspidatus, Aube := LSO 191 Hydroporus cyj>rius, Eegt. 1.3;.7 489 Hydioporus darwiiii 437 1343 Hydroiiorus dauricus, Mun. Cat. = 1331 280 Hydroporus davisii 531 1344 Hydroporus decemlineatus, Man. = 409 644 Hydroporus decemsiguatus, Clk. 1358 247 Hydroi)orus decipiens 580 460 Hydroporus decoratus, Mun. Cat. = 388 1345 Hydrojjorus delectus, Woll. 1359 1.346 Hydroponis delicatulus . 268 544 Hydrojwrus depressicollis, Ros. . 1360 542 Hydroporus depressus, Mun. Cat. = 472 12 Hydroporus despectus .584 299 Hydro],orus diclirous 620 434 Hydroporus dichrous, Melsh. 1361 457 Hydroporus diffoi-mis 615 318 Hydroporus dimidiatus . 517 576 Hydroporus discedens, Regt. = . 611 1347 Hydroporus discicollis, Say 1302 456 Hydroporus discoideus, Lee. 1303 562 Hydrojiorus discretus 504 577 Hjdroporus dispar 440 447 Hydroponis disjiersus 241 238 Hydroporus diversicornis 496 1348 Hydi-oporus dissimilis 408 487 Hydroporus distingnendus, Desb. = 610 556 Hydroporus dohrni 250 309 Hydroporus dorsalis, Mun. Cat. =^ 630 1349 Hydroporus dorsojilagiatus, Fairm. 1364 484 Hydroporus dubius, Aube 1.365 421 Hydroporus duodecimlineatus 530 632 Hydroporus duodecimmaculatus 463 490 Hydroporus duodecirapustulatus, Mun. C at. = 462 1350 Hydroiiorus dujilex 431 310 Hydroponis duponti 325 501 Hydioporus elongatuliis 601 255 Hj'droporus elegautulus, Boh. 1.366 469 Hydroporus einilianus, Clk. 1307 1351 Hydroporus enneagx'ammus 419 508 Hydroporus errans 571 638 Hydroponis eruditus 611 1377 Hydroporus erythrocephalus, Mim. Cat. : 614 1352 Hydroporus erythrostomus, Mann. = 318 300 Hj'drojionis eseheri 536 1353 Hydrojiorus evaiiescens. Boh. 1368 497 Hydroporus exiguus 254 423 Hydroporus exilis, Boh. . 1309 270 Hydrojiorus exLmius 522 1395 Hydrojiorus exornatus . 264 610 Hydrojiorus fairniairei, Lep. 1370 646 Hydrojiorus farctus 384 510 Hydioporus itinoralis 428 1354 Hydroporus fenestratus . 467 237 Hydropoi-us ferrugiueus . 636 648 Hydrojiorus flavicollis 258 1355 Hydroporus flaviculus, Mun. Cat. =: 1335 Index. yy7 Hydroponis flavofasciatiis Hytlroporus flavipes, ]\Iiin. Cat. Hydro])orns flaviveutris . Hydroponis formosus Hydroporus fortis HjHlroporus fossuliponuis, Macl. Hydroporus foveiceps, Macl. = Hydroporus fractilinea, Solsk. Hydroporus fractus Hydroporus fratermis Hydroporus fryi, Clk. Hydroporus fuuereus Hydroporu.s fuscatus Hydroporus fuscipennis . Hydroporus g'ardneri Hydroporus gemellus Hydroporus geminus, Mun. Cat. Hydroporus geiiei Hydrojiorus gigas Hydroporu? gilberti Hydroponis glabriusculus Hydroponis goudotii Hydroporus gracilis, Wehn. Hydroporus granarius Hj-droponis granulans, Mun. Cat, Hydrojiorus graumii Hydroporus gra\-idus, Clk. Hydroporus griseostriatus, Mun. Cat. = Hydroporus gyllenhalli . H3-dropt)rus habelmanni, Welm. Hydroporus haleusis, Muu. Cat. = Hydroporus liamatus Hydroporus hamulatus, Mun. Cat. = Hydroporus hansardii, Clk. Hydroporus liardyi Hydroporus hirtellus Hydroporus hispanicus, Rosenh. Hydroporus hottentottus, Har. Hydroporus liowitti Hydrojiorus liumeralis Hydroporus liiiniilis, Klug. Hydroporus hybridus Hydroporus liydrojiicus . Hydroporus liyphydrioides, Perr. Hydroporus ignotus, Muls. Hydroporus iua^qualis, M. C. = H\"droporus incognitus Hydroporus inconspectus, Lep. Hydroporus inconspicuus, Lee. = Hydroponis incrassatus, Tli. Hydroporus ineiSciens, Walk. Hydroponis ineptus Hydroporus infacetus, Clk. Hydroporus infaustus, Clk. Hydroporus iniirmus. Boh. Hydroporus inoequalis, Mun. Cat, Hydrojiorus inornatus Hydrojiorus inquinatus, Boh. Hydrojiorus insignis Hydroporus inscitus Hydroporus insculjitilis . Hydroporus iusularis Hydrojiorus integer Hydrojiofus iuteiinixtus il) .111 o47 420 .53.5 (lis 3.54 444 1371 510 405 1.372 524 320 507 447 301 209 53'J 427 433 595 202 1373 322 541 23.5 1374 493 599 1375 528 445 274 1370 643 588 {$) 455 1377 444 G09 1378 5 1 9 383 1379 381 611 1380 308 1381 13S2 570 1383 1384 1385 381 621 1386 474 574 374 557 499 289 Hydroporus interpulsus, Walk. Hydrojjorus interrogationis Hj'droporus ionicus Hydrojiorus jajjonicus Hyilrojiorus jucundus Hyilrojiorus kingi, Clk. . Hydroporus kolstromi Hydroporus kraatzii Hydroporus laccophilinus, Leo. Hydroporus lacustris Hydroporus lastabilis Hydrojjorus laiticulus Hydrojiorus Ifeviventris Hydrojiorus lauceolatus, Walk Hydroporus lajijionum, Mun. Cat, Hydroporus larejmei Hydroporus latebrosus Hydrojiorus latebrosus, Lee. Hydrojiorus lateralis, Boli. Hj'droporus latifrons Hydroporus latipes Brulle Hydrojiorus latissimus Hydroporus latus Hydroporus lautus Hydroporus lepidus, Mun. Cat. = Hydroporus leprieuri, Eeiche = Hydrojiorus lerneus Hydrojiorus libeus Hydrojiorus lilijiutanus . Hydroporus limliatus Hydrojiorus lineatus, Mun. Cat. = Hydrojiorus lineolatus Hydroporus lineolatus, Lee. = Hydroporus lituratus Hydrojiorus lobatus Hydroporus longicornis . Hydrojioi'us longiusculus Hydroporus longulus, Muls. Hydroporus lucasi, Reiehe Hydroporus luctuosus H3'drojionis luguliris Hydroporus hiridus, Macl. - Hj'drojiorus lutulentus, Lee. = , Hydroporus lutesceus Hydrojiorus lynceus Hydrojiorus macularis, Lee. = . Hydrojiorus magensis, Clk. . Hydrojiorus malaocK, Clk. Hydrojiorus ruarginatus, Muu. Cat. = Hydrojiorus marklini, Mun. Cat. Hydrojioius martinii Hydrojiorus niasoulLuus, Crotch. . Hydrojiorus masters! Hydrojiorus maurns Hydrojiorus meadfooti Hydrojiorus medialis Hydroporus melanarius . Hydrojiorus melaiicholicus, Motsch. Hydrojiorus melanocejihalus, Mun. Cat. Hydroporus mellitus Hjdrojiorus memnonius, Mun. Cat. := Hydrojiorus meridionalis Hydroporus mexieanus . Hydrojiorus miersi, Mun. Cat. = 6 U 3 1387 429 010 286 551 1388 629 631 1389 319 62 545 473 1390 617 454 642 1391 1392 623 1393 240 461 418 534 536 415 526 316 578 537 278 500 669 504 554 593 1394 1395 400 647 299 587 398 506 318 1396 191 582 396 485 1397 284 673 364 401 555 1398 598 502 558 540 527 313 9j8 On Aquatic Carnlcorous Coltoptera or iJytiscidce. Hyili'i'iis niiuutissimus l!G7 Hydrojiorus piceus, Steph. 1414 Hydropoius niixtus 52(1 Hydroponis picieornis . 637 Hvilioiwrus inixtiis(Motscli.) Mun. Cat. = 1332 Hydrojiorus picipes, Mun. Cat. . 409 Hyilroporus moilestus C27 Hydrojiorus pictodes 256 H ydroporus mccstus 45 Ci Hydroporus pictus, Mun. Cat. = 548 llyihopurns ma'St\is, ^Y;^lk. 1399 Hydroporus jiiochardi, Kegt. 1415 1 lyilropoius monilicornis Salil. 1400 Hydrojiorus plauatus, Mann. 1416 HydmiJCirus monticola, Sharp = 555 Hydrojiorus planus, Mun. Cat. = 575 Hyilroponis moriu 598 Hyilrojiorus jilatynotus . 459 Hy,aittatus, Eegt. 1401 Hyilrojiorus plicipeiinis . 257 Ilyilioporus multiniaculatus 3iJ5 Hydrojiorus jiolitus, Macl. 1417 Ily droporus unguieidaris, Crotch 1447 Hydroporus uni§triatus, Mun. Cat. := 261 Hydroporus vagppictus . 613 Hydroporus varjegatus . 481 Hydroporus varjus 544 Hydroporus veuator 581 Hydroporus venustus, Lee. = 519 Hydroporus vestitus, Gebl. 1448 Hydroporus vicLnus 538 Hydroporus vigilans 465 Hydroponis vilis 641 Hydroporus vitiosus 514 Hydrojioiiis vittatijiennis 500 Hydrojiorus vittatus 515 Hydroporus vittieollis, Boh. 1449 Hydropprus vittula . . 608 Hydro[iorus wakefieldi Hydri ijiorus wardii Hydroporus wollastoni HVDROTRUPES Hydrotruptes palpalis HVDEOVATINI HVDROVATUS Hydrovatus acuminatiis Hydrovatus acutus Hydi-ovatus aristidis Hydi-ovatus badeni H3drovatus bonvoulorii Hydrovatus brevipes Hydrovatus caraibus Hydrovatus castaneus Hydrovatus clypealis Hydrovatus compactus Hydrovatus compressus Hydrovatus confertus Hydrovatus crassulus Hydrovatus cribratus Hydrovatus elevatus Hydrovatus faseiatus Hydrovatus fei'rugatus, Eegt. Hydrovatus flaminidatus Hydrovatus fractus Hydrovatus fulvesceus . Hydrovatus fusculus Hydrovatus hornii, Crotch Hydrovatus huiuilis Hydrovatus longicornis . Hydrovatus maculatus . Hydrovatus maculatus, Motsch, Hydrovatus major Hydrovatus nigricans Hydrovatus nigrita Hydrovatus obscurus, Motsch. H \drovatns obtusus Hyrhovatus opaeus Hydi-ovatus ovalis Hydrovatus j)arallelus . Hydrovatus picipenuis . Hydrovatus pictulus Hydrovatus politus Hydrovatus pumilus Hydrovatus punctipennis, Motsch. Hydrovatus rufescens, Motsch. Hydrovatus seminarius, Motsch. Hydrovatus simjilex Hydrovatus sordidus Hydrovatus subrotundatus, Motsch. Hydrovatus subtilis Hydrovatus sumatrensis Hydi-ovatus tinctus Hygrotus impressifrons, Motsch. Hyphopokus Hyphoporus ajier Hyplioporus elevatus Hypiivdrini Hyphydrus Hyphydius acuminatus Hyphydrus africanus Hyphydrus australis Hyphydrus austrocaledonicus, PeiT. 430 395 441 875 6 337 368 145» 1000 On Aquatic Carnivorous Coleoptera or Ihjtiscidai. Hypliydrus bisulcatus, Clk. =^ Hvpliydrus blanchardi, Clk. := Hyphydrus cafifer, Boll. . Itypliydnis caledonijp, Clk. =z Hypliydiiis cayenneusis, Cast. Hyjihydiais tircuiiiflexus, Klug Hypliydiais contigiius Hypliydrus crassiis Hypliydrus cuspidatus . Hypliydrus dpceuiuiauulatus Hypliydrus dei-oratus Hypliydrus distinctus Hypliydrus exiuiius, Clk. = H\'])liydrus frontalis HyiJiydrus gl 130 ^Macroporous solidus 4-48 109 Mac'rovatellus ji. 840 117 Jlaerovatelhis lateralis 83 124 Macro vatellus marginalis SO 158 JIacrovatellus uiexicanus 87 1482 ilacrovatellus rudis 84 1483 ]\[acrovatellus sahlbergi 85 137 Macrovatellus ventralis 89 160 Matus . p. 895 138 ]\Iatus bicarinatus, Mun. Cat. = 907 142 Matus daemeli . 909 90 Matus wingi 908 1484 MEriADYTES p. 917 157 Megadytes ducalis 1118 152 Megadytes expositus 1103 1485 Megadytes flohri 1109 94 Megadytes fratenius 1107 106 Megadytes gra\'idus 111.5 148G Megadytes obesus 1112 110 Megadytes perplexus 1114 164 Megadytes steiuheili 1108 1487 MeLADE-MA p. 902 126 Meladema coriacea 978 173 Methles p. 873 113 Methles punctipennis 659 170 Methles rectus . 658 1488 Methles spinosus C57 121 Metronectes p. 875 100 Necterosoma p. 86+ 145 Necterosoma arcuatum ++,■5 112 Necterosoma flavicollo, ^ [acl. 1490 1002 Oji Aquatic Carnivorous Coleoptera or Dytiscid"'. Necterosoma regulare 442 NecterosoUia schmeltzi . 438 Necterosoma vittipeune, Macl. . 1497 Neptostersus . ■ P- 843 Neptusternus omatus 175 NOTERIDES !>• 944 KOTERISI ■ P- 919 NOTERUS P- 83G Noterus bicolor . 37 Noterus btiqueti 42 Noterus clavicornis, Mun. Cat. = 20 Noterus coiivexiusculus 22 Noterus crassicomis, Aube = 20 Notei-us grandis . 81 Notei-us imbricatus, Klug. 1498 Noterus japonicua 24 Noterus lievigatus 76 Noteras Isevis 25 Noterus ponticus 23 Noterus semipunetatus, Mun. Cat. = 21 NOTO.MICRUS . . . . P- 833 Notouiicrus brevicoruis . C Notoiiiicrus lievigatus 4 Notomicrus sutuntlis 5 Notoiiiicrus traili 7 (Etiiioxec'tes . . P- 910 Gitliionectes optatus 1072 Oxynoptilns carboiiarius, Mun. Cat. = . 1349 O.xynoptilus cuspidatus, Mun. Cat. = . 180 Oxynoptilns pustulatus, ISIun. Cat. = 18G Pacuvdrds .' . P- 850 Pacliydrus bre\'is 228 Pacliydrus cribratus 225 Pacliydrus obesus 227 Pacliydrus punctatus 224 Pacbyte.s elegaus, Mont. 1499 Paroster . . . . P- SCO Parostcr pallescens 373 Pelobiis . . . . P- 827 Pelobius australasire <•> Pelobius hernianni, Aube = 1 Pelobius niger . . . . 3 Pl-ATAMBUS . . . . P- 889 Platynectks P- 887 Platynectes iienescens 759 Platynectes daenieli 704 Platynectes linil)atus 701 Platynectes obscurus 702 Platynectes ornatifrons . 7G9 Platynectes parananus . 771 Primospes . . . . P- 850 Primospes suturalis 330 PUODATICUS P- 900 Prodaticus pictus • 1005 Pronoterus P- 835 Prouotcrus punctrj)eunis 13 QUEDA .... • P- 849 Queda compressa 222 Ehantaticus • P- 911 Ehantus- • P- 899 Eliantus abeiTaius, Mun. Cat. = 954 Ehantus advcna • 929 Ehantus anisonychus 937 Ehantus aniiecteus 922 Hliantus angusticoUis. Mun. Cat. := . 1211 KluDitus liinotatus, Mun. Cat. = . 935^ Ehantus bistriatua, Mun. Cat. = . 947 Kliantus capeusis, Mun. Cat. = . . 954 Khantus cousiuiilis, Motsch. . . 150O Khanlus consputus, Mun. Cat. = . 95.'i Ehantus darwinii, Mun. Cat. = ■. 1219 Ehantus dcbilis .... 921 Ehantus discedeus . . . 938- Ehantiis discicollis, Muu. Cat. = . 1221 Ehantus divisus, Mun. Cat. = . . 930 Ehantus doiiiinguensis, Mun. Cat. = . 93.'> Ehantus duiionti, Mun. Cat. =: . . 1225 Ehantus olovatus . . . . 92.^ Ehantus exoletus, Mun. Cat. = . 951 Ehantus tlavigriseus, Crotch. . . 150L Ehantus goudoti . . . 958 Ehantus hispanicus . . . 955- Ehantus irroratus, Mun. Cat. = . 926 Ehantus latitans . . . 952 Ehantus longipes . . . 931 Ehantus lutcicollis, Gebl. . . 1502 Ehantus margiuatus . . . 917 Ehantus melanopterus, Muu. Cat. := . 951 Ehantus mexicanus, Mun. Cat. = . 936 Ehantus nigriccps, Mun. Cat. = . 915 Ehantus nigriventris. Motsch. . . 1503 Ehantus nigropunctatus, Motsch. . 1504 Ehantus notaticollis, Mun. Cat. = . 946 Ehantus notatus, Mun. Cat. = . . 947 Ehantus obscuricoUis, Mun. Cat. = . 1241 Ehantus oljscurus . . . 932^ Ehantus jJantaris . . . 923 Ehantus j>lebeius . . . 934 Ehantus pulverosus, Mvm. Cat. = . 924 Ehantus remator . . . 927 Rh.mtus rotundioollis, Mun. Cat. := . 1245 Ehautus sericans . . . 948 Ehantus signatus, Mun. Cat. =: . 926 Ehantus sutlusus . . . 933 Ehautus trilineatus, Mun. Cat. . 926 Ehantus validus . . . 959 Ehantus varius, Mun. Cat. = . . 916 Ehantus vibicicoUis. Mun. Cat. = . 1257 Ehantus vicinus, Muu. Cat. = . . 928 Sandracottus . . . . p. 910 Sandracottus guttatus . . . 1078 Sandracottus hunteri . . . 1073 Sandracottus uauticus . . . 1081 Sandracottus ornatus . . . 1080 Sandracottus rotundus . . . 1079 SCUTOPTERUS . . . • P- 898" Scutopterus angustus, Mun. Cat. = . 918 Scutojitcrus coriacfus, ]\Iun. Cat. = , 978 Scutojitcrus daliuricus, Man. Cat. =: . 960 Scutojiteriis distigiua, Mun. Cat. =: . 1223 Scutopterus horni . . . 919- Scuto])terus imbricatus, WoU. . . 1505 Scutopterus lanio, Mun. Cat. = . 979 Scutopterus pustulatus, Mun. Cat. . 945 Spencerhydrus . . . p. 916 Spencerhydrus lateciuctus . . 1098 Spenccrliydrus pulchellus . . 11)97 Spencorhydrus sewiitiavus . . 1099- Index. 1003 Sternopriscus . Sternopriscus browni Sternopriscus clavatiis Sternopriscus obscurus Sternopriscus oscillator Sternojwiscus signatus Sternopriscus -tarsalis Sternopriscus tasmanicus Sternopriscus wehnckei SUPHIS SUPHISINI Supliis bicolor, Mun. Oat. Suphis cimicoides Suphis diflbrmis Suphis gibbulus Supliis lineatus . Suphis puncticollis, Crotch Suphis semipuuctatus, Lee. Suphis subtUis Synchortus Synchortus aciculatus Synchortus duplicatus Synchortus simplex Synchortus sparsus Thermonectes . Thermonectini . Thermonectes batesi Thermonectes cuneatus Thermonectes depictus Thermonectes intermedins, Crotch Thermonectes simulator . Trochalus rugulosus, Redt. Trogus seneus, Mun. Cat. = Trogus artensis, Mun. Cat. =: Trogus atratus, Mun. Cat. = Trogus bengalensis, Mun. Oat. ^= Trogus bimaculatus, Mun. Cat. = Trogus binotatus, Mun. Cat. = . Trogus bisignatus, Mun. Cat. = Trogus brevis, Mun. Cat. = Trogus buqueti, Mun. Cat. =: Trogus cafler, Mvm. Cat. = Trogus chaudoLri, Mun. Cat =: Trogus chinensis, Mun. Cat. = . Trogus costalis, Mun. Cat. = Trogus dehaani, Mun. Cat. — Trogus dejeani, Mmi. Cat. =: Trogus desjardinsi, Mun. Cat. = Trogus ellipticus, Mun. Cat. = . Trogus explanatus, Mun. Cat. := Trogus fallax, Mun. Cat. = . 8.58 359 361 360 367 363 362 368 366 , 838 , 920 37 27 29 38 48 1.506 1507 28 , 835 15 17 14 16 . 909 , 940 1068 1067 1062 1508 1064 1509 1274 1140 1100 1159 1135 1133 1122 1128 1154 1135 1169 1162 1116 1139 1276 1133 1120 1147 nil Trogns fimbriolatus, Miui. Cat. ^ Trogus flavocinctus, Mun. Cat. = Trogus giganteus, Mun. Cat. =• . Trogus glaucus, Mun. Cat. = Trogus godefFroyi, Wehncke = Trogus goryi, Mun. Cat. = Trogus gotschi, Mun. Cat. = Trogu.'j guerini, Mun. Cat. == Trogus haagi, Wehncke ^= 1^'rogus hookeri, Mun. Cat. =r Trogus immarginatus, Mun. Cat. = Trogus indicus, Mun. Cat. =; Trogus insularis, Mun. Cat. = Trogus jordanis, Mun. Cat. = Trogus liBvigatus, Mun. Cat. = . Trogus latus, Mun. Cat. ^ Trogus Iherminieri, Mun. Cat. = Trogus limbatus, Mun. Cat. = Trogus niadagascariensis, Mun. Cat. = Trogus marginicoUis, Mun. Cat. . Trogus natalensis, Wehn. Trogus nigripes, Wehncke =: Trogus notasicus, Mun. Cat. = . Trogus novsecaledonia^, Mun. Cat. = Trogus occidentalis, Mun. Cat. = Trogus olivaoeus, Mun. Cat. =r . Trogus owas, Mun. Cat. = Trogus posticus, Mun. Cat. = Trogus prosterno-viridis, Mun. Oat. = Trogus puncticollis, Mun. Oat. = Trogus reichei, Mun. Cat. = Trogus robustus, Mun. Cat. = Trogus rugosus, Mun. Cat. =: Trogus rugulosus, Mun. Cat. := Trogus scutellaris, Mim. Cat. = Trogus senegalensis, Mun. Cat. =: Trogus steinheili, Wehncke = Trogus sugillatus, Muji. Cat. = Trogus tataricus, Mun. Oat. := Trogus temnenki, Mun. Cat. =: Trogus tripunctatus, Mun. Oat. Trogus vii-ens, Mun. Oat. = Trogus vulneratus, Mun. Oat. = Tyndailhydrus Tyndallhydrus caraboides Vatellini Vatellus Vatellus grandis, Buq. Vatellus haagi Vatellus lentus . Vatellus tarsatus, Mun. Cat. = 1119 1121 1117 1104 1168 1277 1140 1158 1140 1102 1136 1167 1278 1279 1106 1105 1117 1157 1133 1280 1510 1123 1122 1140 1146 1122 11.35 1127 1282 1110 1148 1113 1167 1509 1101 1145 1108 1122 1295 1140 1140 1169 1283 p. 854 327 p. 921 p. 840 1511 88 91 90 TEANS. ROY. DUB. SOC, N.S., VOL. II. 6 N Dlbmn ; Printed by Alex. Thom & Co., 87, 88, and 89, Abbey-street, The Queen's Printing Office. I'or Her Majesty's Stationery Office. !)24.-l,000.— 4/82. f M^eii. Ti'.ui.s. -K .D. b.Vol. 2.n.s. Plated, E^ 3ft Tt^ 35. 9 Kg 41 Fy4J Fig 44 Fug 42. Rg4S Fig SI. JhgSZ. FigSi Fig SB FLgSl Fig 58 FigSS FigeO FigG) Fig 62 Kg 63 Fig64-. WTurhiss £3 Sharp del Ired^DangeHitU/ Lith, laiLCbru. S cien Trans. JI.D. S, Vol , 2 . n, s . Plate .Ylll A e,ydsrM£ danmrms de Ceer) 1 1 4 CANTHYDRUS (EydTocanthueTwgrums mij)ij II7\^ATELLUS fSyiraporus-kiursatuslapj FraVy DmirjerfLeli- blh,Xtmdmi Scien. Trans. R,D.S.VoL2.n.s. JOateX ITi no rl2 /2.3 727 i!8 DEROVATELLUS (^KuteZiiS ferefeufr.y 121 AMPHizOA (Ameol^is Lec. ': 124- HET£RHVDfH)Sl'3yphydni£smega2ensisJubiJ 127 BIDESSUS fBphaxtiLs) VJS. IS LACCOPHiLus ( L pdhccodus I 122 QUE DA I Q CtympreSSlv ) 125 PACHYDRUS f F puiwtaiice j 128 BIDE3SUS f B zaevgiu6.J 129 I9.Q nrf-"! ■jjrtCiNua fE tndms: j 123 HYDROVATUE flfrfiyar. ) I2G DESMOPACHRIA f d- OVollB.j 123 HUXELHYDRUS f H. 4yniheixcus.) WPurlass id. Tred.'^DcuigeHiJJy iHi london, 223* Scierv Trans. R.D. S.Vol. 2n.s. Plate H, ^■■ r-r- ,€P^ -^ k 13S -xm ■^.'- 130. TYNDALLHVDRUS. ( T caraijovcUs.) 133. PRIMOSPES- ' P. enuburalis.) 136. HYPHYDRUS, ( Unuxjor.) 139. HVPHYDRUS ( H OLiEtraiu! S] 131 ANDE)^ ( A--m^i^TcU^} 134 CCELHYDRUS. / C . ireyuxUu! ) 137 HYPHYDRUS. f S.japortucus o' ) 140 STERNOPRISCUS. ( Sbrovmu. S.) W Pia-hss del 132. HYDROPEPLUS. (Sydroporiie trimoailaiu£ 135. DARWlNHYDRUa/Xi sbUdun] 138. HYPHYDfiUS. ( Ejaporacus.s) l + l, STERNOPRISCUSY'S'. irowu/ $.) ^ 2502 S CI en. Trans. R. D. S.Vol. 2.n.s Plate m V ."^ ^ ^-, "' ^ ««fc I42.HYPH0P0RUS fs^droporus sobers ajuic J M3 PAROSTER [PpcMesans-.j 144. HEROPHYDRUS fjlheros.j 145 CCELAMBUS. f'Kyiroporus ajcarcAcslcc) I46CCELAMBUS (C.-nutuue.) li?. CCELAMBUS. f Hydrapcras mJiiki^ Ice.) 148 CH0STONECTES./'iiyA-opCTn'J^.' -Li/h'landon/ 2S01. Scien.Traiis.ilD-S.Vol. l.n. Plate Xni 162 763 ^ 1^1- 154. DERONECTES (Hyinjpmus carmMuM Auii.j 155. DERO^ECTtS ( B^d^apmus sU-uUzUm^ icc.j \bi. momomS /K^s.corw ) 157. HVDROPORUS ( BsvnhJuoXus Say.) 160. HYDROPORUS fj. aMUnius CroCcki) 163. HYDROTRUPES (E palpcbUsJ WPurTuxs ill 58. HYDROPORUS ( Syphyinie LafpOKum GyW.) M'i. mWQVOVMZ (H n^mepi Sciuujmj lei CEIINA. (C aaduilou Jwbe.) ISZ. METHLES (MyMnO^m-as) ^^, m^Um^alS(A^aiu.a^P^r..) ,65. ACABUS ^^T^J^tl^^ Saen. Trai\s. R. D. S .Vol. 2.n. s PkLeHV. 765 770 771 m 1T} 166 ACABUS acj^hdal^^JUcJ,^) Kl AGAB'JS f Dyt^aus hm,au>^ Tai } 168 ACAB'JS / A giUfOies A.JjeJ I69.ACABUS (AJusniUgrcUu^ ) I'O ACABUS f Colymiezes Uaru^ Srb j 171 ACA8US /.^, «M^««tf. j I72.A0ABUS ^i)ytea« yu5ap«m.Pa^/t.j 173 ACABUS f DyUsr,:^ serru^rnu ra^k.) ^.7 1^ \m\OSOm fAgah^reguhr^ Ice j l75.PLATYNECrES /'.Dyte^cw iecmf^tuyctoMu^Fai varj 176 PLATYNtCTES (AgaJbus v^^ca,ujuauJusAJ>i) 177. L£ljmNECTF.S/G.^wgr^^^^^Z^ >J Sden Trans. R.D.S. Vol. 2 n_s. Plate JV 179 IdV 182 178 AGAMETRUS fCobymities penmamu; Cast j ISI.ILYBIUS flcUscedmej 184', COPELATUS (C-m-grxbJhiS.) 187. COPELMUS (GUymheiu su2aperavut &st,J WMcuss dd. 179, ACABINUS fColymhetes glahrMuu<:Mei.! 115 223. CYBISTER ^C...a.^J 22.. CYBISTER . fDyt^cus l^^nia.^ Fa^J ^25. CY^SUR^^/^^Ti^'^.i. WPurhes iel^. SMITHSONIAN INSTITUTION UBRARIES lllllllliiillMi 3 IDfifi DD2E0mb 5 nhent qQL596 09S53 On aquatic camivofous Coleoptera of l>yi