The geographical distribution of animals, with a study of the relations ...

Ghap. x.] THE PAL^ARCTIC REGION. 189much more abundant in the southern than the northern halfof the region. Several Oriental genera extend to Japan andNorth China, and a few Ethiopian genera to North Africa.Thirteen genera are confinedto the two north temperate regions.Several large genera, such as Dorcadion (154 species), Phytcecia(85 species), Pogonochmrus (22 species), Agapanthia (22 species),and Vesperus (7 species), are altogether peculiar to the Patearcticregion ; and with a preponderance of Leptura, Grammoptera,Stenocorus, and several others, strongly characterise it asdistinct from the Nearctic and Oriental regions.The other familieswhich are well developed in the Palsearcticregions, are, the Staphylinidre or rove-beetles, Silphidse orburying-beetles, Histeridae or mimic-beetles, Nitidulidse, Aphodiidse,Copridse (especially in South Europe), Geotrupidse ordung-beetles, Melolonthidse or chafers, Elateridee or clickbeetles,the various families of Malacoderms and Heteromera,especially Pimeliida? in the Mediterranean sub-region, Curculionidseor weevils, the Phytophaga or leaf-eaters, and Cocinellidaeor lady-birds.The number of species of Coleoptera in the western part ofthe Palrearctic region is about 15,000, and there are probablynot more than 2,000 to add to this number from Siberia.Japan, and North China; but were these countries as wellexplored as Europe, we may expect that they would add atleast 5,000 to the number above given, raising the PalaearcticColeopterous fauna to 20,000 species. As the total number ofspecies at present known to exist in collections isestimated (andperhaps somewhat over-estimated) at 70,000 species, we maybe sure that were the whole earth as thoroughly investigatedas Europe, the number would be at least doubled, since wecannot suppose that Europe, with the Mediterranean basin, cancontain more than one-fifth of the whole of the Coleoptera ofthe globe.Of the other orders of insects we here say nothing, because intheir case much more than in that of the Coleopteraand Lepidoptera,is the disproportion enormous between our knowledge ofthe European fauna and that of almost all the rest of the globe.