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confined to the Palaearctic region. In the Ægeriidae the genus Ageria is mainly Palaearctic. The Sphingidae have a wider general range, and none of the larger genera are peculiar to any one region. Coleoptera.-The Palaearctic region is the richest portion of the globe in the great family of Carabidae, or predacious groundbeetles, about 50 of the genera being confined to it, while many others, including the magnificent genus Carabus, have here their highest development. While several of the smaller genera are confined to the eastern or western sub-regions, most of the larger ones extend over the whole area, and give it an unmistakable aspect; while in passing from east to west or vice-versá, allied species and genera replace each other with considerable regularity, except in the extreme south-east, where, in China and Japan, some Oriental forms appear, as do a few Ethiopian types in the south-west. Cicindelidae, or tiger-beetles, are but poorly represented by about 70 species of the genus Cicindela, and a single Tetracha in South Europe. Lucanidae, or stag-beetles, are also poor, there being representatives of 8 genera. One of these, Æsalus (a single species), is peculiar to South Europe, and two others, Cladognathus and Cyclopthalmus, are only represented in Japan, China, and Thibet. Cetoniidae, or rose-chafers, are represented by 13 genera, two of which are peculiar to South Europe (Tropinota and Heterocnemis), while Stalagmosoma, ranging from Persia to Nubia, and the fine Dicranocephalus inhabiting North China, Corea, and Nipal, may also be considered to belong to it. The genera Trichius, Gnorimus, and Osmoderma are confined to the two north temperate regions. Buprestidae, or metallic beetles, are rather abundant in the warmer parts of the region, 27 genera being represented, nine of which are peculiar. By far the larger portion of these are confined to the Mediterranean sub-region. A considerable number also inhabit Japan and China. . The Longicorns, or long-horned beetles, are represented by no less than 196 genera, 51 of which are peculiar. They are much more abundant in the southern than the northern half of the region. Several Oriental genera extend to Japan and North China, and a few Ethiopian genera to North Africa. Thirteen genera are confined to the two north temperate regions. Several large genera, such as Dorcadion (154 species), Phytaecia (85 species), Pogonochaerus (22 species), Agapanthia (22 species), and Vesperus (7 species), are altogether peculiar to the Palaearctic region; and with a preponderance of Leptura, Grammoptera, Stenocorus, and several others, strongly characterise it as distinct from the Nearctic and Oriental regions.
The other families which are well developed in the Palaearctic regions, are, the Staphylinidae or rove-beetles, Silphidae or burying-beetles, Histeridae or mimic-beetles, Nitidulidae, Aphodiidae, Copridae (especially in South Europe), Geotrupidae or dung-beetles, Melolonthidae or chafers, Elateridae or clickbeetles, the various families of Malacoderms and Heteromera, especially Pimeliidae in the Mediterranean sub-region, Curculionidae or weevils, the Phytophaga or leaf-eaters, and Cocinellidae or lady-birds.
The number of species of Coleoptera in the western part of the Palaearctic region is about 15,000, and there are probably not more than 2,000 to add to this number from Siberia, Japan, and North China; but were these countries as well explored as Europe, we may expect that they would add at least 5,000 to the number above given, raising the Palaearctic Coleopterous fauna to 20,000 species. As the total number of species at present known to exist in collections is estimated (and perhaps somewhat over-estimated) at 70,000 species, we may be sure that were the whole earth as thoroughly investigated as Europe, the number would be at heast doubled, since we cannot suppose that Europe, with the Mediterranean basin, can contain more than one-fifth of the whole of the Coleoptera of the globe.
Of the other orders of insects we here say nothing, because in their case much more than in that of the Coleoptera and Lepidoptera, is the disproportion enormous between our knowledge of the European fauna and that of almost all the rest of the globe. They are, therefore, at present of comparatively little use for purposes of geographical distribution, even were it advisable to enter into the subject in a work which will, perhaps, be too much overburdened with details only of interest to specialists.
Land Shells—These are very numerous in the warmer parts of the region, but comparatively scarce towards the North. South Europe alone possesses over 600 species, whereas there are only 200 in all Northern Europe and Asia. The total number of species in the whole region is probably about 1,250, of which the great majority are Helicidae; the Operculated families being very poorly represented. Several small genera or sub-genera are peculiar to the region, as Testacella (West Europe and Canaries); Leucochroa (Mediterranean district); Acicula (Europe); Craspedopoma (Atlantic Islands); Leonia (Algeria and Spain); Pomatias (Europe and Canaries); Cecina (Mongolia). The largest genera are Helic and Clausilia, which together comprise more than half the species; Pupa, very numerous; Bulimus and Achatina in moderate numbers, and all the rest small. Helic is the only genus which contains large and handsome species; Bulimus and Achatina, so magnificent in tropical countries, being here represented by small and obscure forms only. Daudebardia is confined to Central and South Europe and New Zealand; Glandina is chiefly South American; Hyalina is only American and European; Buliminus ranges over all the world except America; and the other European genera of Helicidae are widely distributed. Of the Operculata, Cyclotus, Cyclophorus, and Pupina extend from the Oriental region into Japan and North China; Tudoria is found in Algeria and the West Indies; Hydrocena is widely scattered, and occurs in South Europe and Japan. The genera of freshwater shells are all widely distributed.
THE PALFARCTIC SUB-REGIONS.
The four sub-regions which are here adopted, have been fixed upon as those which are, in the present state of our knowledge, at once the most natural and the only practicable ones. No doubt all of them could be advantageously again subdivided, in a detailed study of the geographical distribution of species. But in a general work, which aims at treating all parts of the world with equal fulness, and which therefore is confined almost wholly to the distribution of families and genera, such further subdivision would be out of place. It is even difficult, in some of the classes of animals, to find peculiar or even characteristic genera for the present sub-regions; but they all have well marked climatic and physical differences, and this leads to an assemblage of species and of groups which are sufficiently distinctive.
I. Central and Northern Europe.
This sub-region, which may perhaps be termed the “European,” is zoologically and botanically the best known on the globe. It can be pretty accurately defined, as bounded on the south by the Pyrenees, the Alps, the Balkans, the Black Sea, and the Caucasus range; and by the Ural Mountains, or perhaps more correctly the valley of the Irtish and Caspian Sea, on the east; while Ireland and Iceland are its furthest outliers in the west. To the north, it merges so gradually into the Arctic zone that no demarcation is possible. ' The great extent to which this sub-region is interpenetrated by the sea, and the prevalence of westerly winds bringing warmth and moisture from an ocean influenced by the gulf-stream, give it a climate for the most part genial, and free from extremes of heat and cold. It is thus broadly distinguished from Siberia and Northern Asia generally, where a more extreme and rigorous climate prevails.
The whole of this sub-region is well watered, being penetrated by rivers in every direction; and it consists mainly of plains and undulating country of moderate elevation, the chief mountain ranges being those of Scandinavia in the north-west, and the extensive alpine system of Central Europe. But these are both of moderate height, and a very small portion of their surface is occupied either by permanent snow-fields, or by barren uplands inimical to vegetable and animal life. It is, in fact, to these, and the numerous lesser mountains and hills which everywhere diversify the surface of Europe, that the variety and abundance of its animal life is greatly due. They afford the perennial supplies to rivers, and furnish in their valleys and ever varying slopes, stations suited to every form of existence. A considerable area of Central Europe is occupied by uplands of moderate elevation, a comparatively small portion being flat and marshy plains. Most of the northern and much of the central portions of Europe are covered with vast forests of coniferous trees; and these, occupying as they do those tracts where the winter is most severe, supply food and shelter to many animals who could not otherwise maintain their existence. It is probable that the original condition of the greater part, if not the whole, of temperate Europe, except the flat marshes of the river valleys and the sandy downs of the coast, was that of woodland and forest, mostly of deciduous trees, but with a plentiful admixture of such hardy evergreens as holly, ivy, privet, and yew. A sufficient proportion of these primeval woods, and of artificial plantations which have replaced them, fortunately remain, to preserve for us most of the interesting forms of life, which were developed before man had so greatly modified the surface of the earth, and so nearly exterminated many of its original tenants. Almost exactly in proportion to the amount of woodland that still remains in any part of Europe, do we find (other things being equal) the abundance and variety of wild animals; a pretty clear indication that the original condition of the country was essentially that of a forest, a condition which only now exists in the thinly inhabited regions of the north. Although the sub-region we are considering is, for its extent and latitude, richly peopled with animal life, the number of genera altogether peculiar to it is not great. There are, however, several which are very characteristic, and many species, both of the smaller mammalia and of birds, are wholly restricted to it. Mammalia.-The genera wholly confined to this sub-region are