confinis Dej. DISONYCHA Chevr. 5-vittata. Altica 5-vit. Say. J. Ac. 4, 85. GRAPTODERA Chevr. cuprea. ignita. Alt. ignita Ill. Mag. 6, 117. GALLERUCA Fabr. canadensis Kb. N. Z. 219. gelatinariæ Fabr. El. 1, 490. Olivieri Kb. N. Z. 218. HIPPODAMIA Chevr. Redt. abbreviata Dej. Cat. Coccinella abb. Fabr. E. 1, 360. parenthesis. Coccinella par. Say. J. Ac. 4, 93. 5-signata. Coccinella 5-sig. Kb. N. Z. 230. 13-punctata Dej. Cat. Cocc. 13-pune. Lin. Fn. Su. 481. C-tibialis Say. J. Ac. 4, 94.' COCCINELLA Lin. 9-hotata F. El. 1, 366. 48 Nor have I compared this species. 49 Corpus alatum breviter oblongum antice subangustatum glabrum. Antennæ capite breviores articulo 2 ndo majusculo, ultimo ovali majore. Ligula emarginata. Scutellum distinctum. Ungues simplices. Epipleuræ impressæ. Abdomen articulo 1 mo laminarum margine externo curvato. O. moerens. Niger nitidus, punctulatus, thoracis margine, elytrorumque gutta minuta pone medium testaceis, antennis tarsisque rufis. Long. 1. St. Ignace. Variat, a elytris gutta altera parva humerali testacea, margine pone medium rufescente. Niger immaculatus. 50 S. caudalis,- Breviter ovalis, convexus, punctatus, niger, thorace lateribus, antennis, palpis pedibus, abdominisque segmentis 2 ultimis rufis, mesosterno lato, fere truncato, abdominis laminis integris, basi punctatis, ad marginem segmenti 1 mi fere extendentibus. Long. 09. & articulo ultimo abdominis late profunde emarginato, pedibus capiteque rufis. Plate 8th represents twelve new species of the Coleoptera, described in the preceding Catalogue. On glancing over the catalogue which is just ended, the entomologist cannot fail to be struck with two very remarkable characters displayed by the insect fauna of these northern regions. First, the entire absence of all those groups which are peculiar to the American continent. Thus, there is no Dicælus, no Pasimachus among the Carabica; the Brachelytra are represented only by forms common to both continents. Among the Buprestidæ is no Brachys; in the Scarabæidæ, the American groups (except Dichelonycha) are completely unrepresented; in brief, there is scarcely a genus enumerated which has not its representative in the Old World. The few new genera which I have ventured to establish, are not to be regarded as exceptions, they are all closely allied to European forms, and by no means members of groups exclusively American. Secondly, the deficiency caused by the disappearance of characteristic forms, is obviated by a large increase of the members of genera feebly represented in the more temperate regions, and also by the introduction of many genera heretofore regarded as confined to the northern part of Europe and Asia. Among these latter are many species which can be distinguished from their foreign 51 S. lacustris.-Breviter ovalis, convexus, punctatus, niger, mesosterno lato fere truncato, abdominis laminis integris, basi punctatis, ad marginem segmenti, Imi fere extendentibus. Long. 09. articulo ultimo abdominis profunde triangulariter impresso; basi minus dense punctata; pedibus vel rufis, vel piceis, rufo-marginatis. abdomine integro, æqualiter dense punctato, antennis pedibusque nigris, posticis nonnunquam rufis. 52 S. ornatus.-Ellipticus, convexus dense subtiliter punctatus, niger elytris utrinque macula magna obliqua ante medium, alteraque magna orbiculata pone medium læte rufa, antennarum basi tibiis tarsisque fusco-rufis, abdominis laminis extrorsum omnino obliteratis, mesosterno lato, parum emarginato. Long. 08. 16* analogues only by the most careful examination. This parallelism is sometimes most exact, running not merely through the genera, but even through the respective species of which they are composed; thus of the two species of Olisthærus, each is most closely related to its European analogue, O. laticeps being similar to 0. megacephalus, while O. nitidus can scarcely be known from 0. substriatus. While upon this subject, we may take occasion to distinguish the different kinds of replacement of species, which are observed in passing from one zoological district to another more or less distant. There appear to be four distinct modifications by which faunas are characterized. 1st. When the same species, or organic forms, so similar as to present no appreciable difference, appear at points so situated as to preclude the possibility of any intercommunication. These are most rare, and are only observed when the physical circumstances under which the species exists are nearly identical. 2d. When a species in one district is paralleled by another in a different region so closely allied that upon a superficial glance they would be regarded as the same. These are called analogous species; e. g., the Olisthæri, Spondyli, Bembidia, Helophori, &c., &c., of the preceding catalogue, as compared with European species. 3d. Where several species in one region are represented by several others of the same genus, which perform a similar part in the economy of nature, without, however, displaying any farther affinity to each other. These are called equivalent species; e. g., most of the species of Cicindela, Brachinus, Clytus, Donacia, &c., of America, as compared with those of the eastern world. 4th. Where the members of a group are represented collectively by kindred species in another district, which however display such differences of structure that each may at once be referred to its proper locality; e. g., most of the Melolonthæ among Coleoptera, and the entire group of Quadrumana among mammalia. Now it will be observed, that in proceeding from the Arctic circle to the tropics, the prominent character of the fauna is successively modified by these peculiarities. We pass from a region where the fauna is the same at remote points, through one where the productions are similar, but not identical, to one finally, where the equilib rium of forms is still preserved, but where the general arrangement is totally different, the prominent groups of one continent being either feebly represented on the other, or else entirely wanting. It does not become us, in the present imperfect state of tropical exploration, to determine what groups are peculiar to each continent; we can merely say that particular forms are more abundant in certain regions. For by a strange fatality, (at least in Coleoptera,) no sooner is any group admitted by a common consent to be exclusively American, than suddenly, as if produced by the well-known jugglery of those countries, a species starts up in Central Asia, or Africa, (e. g., Galerita, Agra, Sandalus.) Still, enough remains to show us that the prevailing character of tropical fauna is individuality; the production of peculiar forms within limited regions: while the distinguishing feature of temperate and arctic fauna is the repetition of similar or identical forms through extensive localities. On proceeding now to illustrate these deductions by special examples from the catalogue before us, it will be seen that the parallelism of species in temperate and frigid climates can be demonstrated more particularly in the genera which are more universally diffused over the earth, or in those which are especially confined to temperate regions, than in such as receive their principal development within the tropics. Thus for instance, among the great group of Carnivorous Coleoptera, the terrestial species, (although well represented in cold climates,) contain an immense number of genera, each of which (with few exceptions) seems to have a particular locus, external to which it is feebly represented. Accordingly in this group, the parallelism of species is by no means clear, and the forms are rather to be considered equivalent than analogous. On the other hand, among the aquatic Predaceous Coleoptera, the genera are but few, and the tribe is more abundant in cold regions; and in these the parallelism is most exact, so that there are but few mentioned in the preceding pages, that have not their exact counterparts in Europe. The characters appended to the new species will render this sufficiently obvious to the student, while the relations of those previously described by Kirby and Aubé have already been clearly pointed out by those authors. Passing on to the other water-beetles, the species of Helophorus and Ochthebius will afford other striking examples of this parallelism. Among the Brachelytra are numerous other instances, the most remarkable being the genus Olisthærus, already alluded to. Proteinus and Megarthrus also for the first time appear on this continent. The Aphodii with large scutellum, the Ditylus, Pytho, Sphæriestes, and Spondylus are also good illustrations. Among the Elateridæ are numerous instances, but having not yet submitted this group to philosophical study, I have not ventured to describe the new species, but have merely indicated them by names. For the present therefore, any remarks on the parallelism of the forms in this group must be postponed. Notwithstanding this approximation to a uniform, subarctic standard, we still find in these boreal regions, a prevailing character of North American fauna-the extreme paucity of Curculionidæ. The Donacia too, although numerous, do not afford any prominent parallelism. The American species can only be regarded as equivalent to the European. On concluding this short essay on the geographical distribution of Coleoptera in the northern part of our continent, I feel that some cause must be assigned for the brief manner in which such extensive material has been disposed of. Enough has been given to point the laws of distribution, and to show that they accord most perfectly with those derived from other branches of natural history, while during the yet imperfect condition of entomological science in this country, a minute analysis of the components of the entire fauna would be a work of immense labor, and would in fact be rendered nugatory, until all the species are described, and all the groups submitted to a philosophical revision. My complete success in tracing the parallelism between the Pselaphide of Europe and North America (in an unpublished monograph of this family) leads me to believe that a rich store of material is herein presented to such minds as are satisfied with statistical comparisons between the inhabitants of different zoological districts; and that nothing but industry and a free access to the most common European insects is required to produce a most formidable list of analogous species. I shall rest satisfied with having shown that this parallelism exists even more accurately than in the vertebrate class, and with having pointed out examples far more numerous than those furnished by the higher animals: the more so, |