« EelmineJätka »
sub-region which never cross the narrow seas to the east of them; 6 others which only pass to Celebes; and 2 more which have extended from Java along the closely connected line of islands eastwards to Timor. On the other side, we find 5 strictly Austro-Malayan genera, and 2 others which have a single representative in Java. The following is a list of these genera :—
Indo-malayan Genera :—Amathusia, Thaumantis, Tancecia, Eurytela, Ilerda, Zemeros, Taxila, Aphneus, Prioneris, Dercas, Chrome, Adolias, Apatura, Limmitis, lolaus, Leptocircust (the last six reach Celebes); Discophora, Thestias', (the last two reach Timor.)
Austro-malayan Genera:—Hamadryas, Hypocista, Mynes, Dicallaneura, Elodina, Hyades, Prothoe (the last two reach Java).
The most characteristic groups, which range over the whole Archipelago and give it a homogeneous character, are the various genera of Danaidse, the genus Elymnias, and Amblypodia with a few other Lycsenidse. These are all abundant and conspicuous groups, but they are nevertheless exceptions to the general rule of limitation to one or other of the regions. The cause of this phenomenon is probably to be found in the limitation of the larvae of many Lepidoptera to definite species, genera, and families of plants; and we shall perhaps find, when the subject is carefully investigated, that the groups which range over the whole Archipelago feed on genera of plants which have an equally wide range, while those which are limited to one region or the other, have foodplants belonging to genera which are similarly limited. It is known that the vegetation of the two regions differs largely in a botanical sense, although its general aspect is almost identical; and this may be the reason why the proportion of wide-ranging genera is greater among such insects as feed upon dead wood, than among those which derive their support from the juices of the living foliage. This subject will be again discussed under the various families of Coleoptera, and it will be well to bear in mind the striking facts of generic limitation which have been here brought forward.
Fossil Butterflies, apparently of existing genera, occur in the Miocene and Eocene formations, and an extinct form in the Lower Oolite; but these cannot be held to give any adequate idea of the antiquity of so highly specialised a group, which, in all probability, dates back to Palaeozoic times, since one of the Bombycida?,—a group almost as highly-organised—has been discovered in the coal formation of Belgium. (See VoL I. p. 168.)
Geodephaga, or Carnivorous Ground Beetles.
The Geodephaga consist of two families, Cicindelidse and Carabidse, differing in their form and habits no less than in their numbers and distribution. The former, comprising about 800 species, are far more abundant and varied in Tropical regions; the latter, more than ten times as numerous, are highly characteristic of the North Temperate zone, where fully half of all the known species occur.
CICINDELIDiE. (35 Genera, 803 Species.)
The Cicindelidae, or Tiger Beetles, are a moderately extensive group, spread over the whole globe, but much more abundant in tropical than in temperate or cold countries. More than half of the species (418) belong to the single genus Cicindela, the only one which is cosmopolitan. The other large genera are,— Gollyris (81 sp.), wholly Oriental; Odontochila (57 sp.), South American, with species in Java and Celebes; Teiracha (46 sp.), mostly South American, but with species in South Europe, North America, and Australia; Tricondyla (31 sp.), characteristic of the Oriental region, but extending eastward to New Guinea; Ctenostoma (26 sp.), wholly Neotropical; Dromica (24 sp.), wholly African, south of Lake Ngami and Mozambique; Thtrates (18 sp.), wholly Malayan, from Singapore to New Guinea.
The genera are distributed in the several regions as follows:— the Nearctic region has 5 genera, 3 of which are peculiar to it; the Palsearctic has 2, but none peculiar; the Ethiopian 13, with 11 peculiar; the Oriental 8, with 3 peculiar; the Australian 9, with 2 peculiar; and the Neotropical 15, with 10 peculiar. The connection between South America and Australia is shown by the latter country possessing 9 species of the characteristic South American genus Tetracha, as well as one of Megacephala. The small number of peculiar genera in the Oriental and. Australian regions is partly owing to the circumstance that two otherwise peculiar Oriental genera have spread eastward to the Moluccas and New Guinea, a fact to be easily explained by the great facilities such creatures have for passing narrow straits, and by the almost identical physical conditions in the Malayan portion of the two regions. The insects of Indo-Malaya were better adapted to live in the Austro-Malay Islands than those of Australia itself, and the latter group of islands have thus acquired an Oriental aspect in their entomology, though not without indications of the presence of an aboriginal insect-fauna of a strictly Australian type. The relation of the Australian and Neotropical regions is exhibited by this family in an unusually distinct manner. Tetracha, a genus which ranges from Mexico to La Plata, has 9 species in Australia; while Megacephala has 2 American and 1 Australian species. Another curious, and more obscure relation, is that between the faunas of Tropical America and Tropical Africa. This is also illustrated by the genus Megacephala, which has 4 African species as well as 2 South American; and we have also the genus Peridexia, which has 2 species in South America and 2 in Madagascar.
Several of the sub-regions are also well characterised by peculiar genera; as Amblychila and Omus confined to California and the Eocky Mountains; Manticora, Ophryodera, Platychile, and Dromica, characteristic of South Africa; Megalomma and Pogonostoma peculiar to the Mascarene Islands; and Caledonica to the islands east of New Guinea. The extensive and elegant genus Collyris is highly characteristic of the Oriental region, over the whole of which it extends, only just passing the limits into Celebes and Timor.
The Cicindelidse, therefore, fully conform to those divisions of
the earth which have been found best to represent the facts of distribution in the higher animals.
CAEABIDJE. (620 Genera, 8500 Species.)
The enormous extent of this family, necessitates a somewhat general treatment. It has been very extensively collected, while its classification has been most carefully worked out, and a detailed exposition of its geographical distribution by a competent entomologist would be of the greatest interest. A careful study of Gemminger and Harold's Catalogue, however, enables me to sketch out the main features of its distribution, and to detail many of its peculiarities with considerable accuracy.
The Carabidse are remarkable among insects, and perhaps among all terrestrial animals, as being a wonderfully numerous, varied, conspicuous, and beautiful group, which is pre-eminently characteristic of the Palaearctic region. So strikingly and unmistakably is this the case, that it must be held completely to justify the keeping that region distinct from those to which it has at various times been proposed to join it Although the CarabidfB are thoroughly well represented by hosts of peculiar genera and abundant species in every part of the world without exception, yet the Pakearctic region alone contains fully onethird, or perhaps nearer two-fifths, of the whole. It may also be said, that the group is a temperate as compared with a tropical one; so that probably half the species are to be found in the temperate and cold regions of the globe, leaving about an equal number in the much more extensive tropical and warm regions. But, among the cold regions, the Pakearctic is pre-eminent North America is also rich, but it contains, by far, fewer genera and fewer species.
The magnificent genus Cardbus, with its allies Procerus and Procrustes, containing about 300 species, all of large size, is almost wholly confined to the Palsearctic region, only 10 species iuhabiting North America, and 11 Temperate South America, with one on the African mountain of Kilimandjara Twelve large genera, containing together more than 2000 species, are truly cosmopolitan, inhabiting both temperate and tropical countries all over the globe; but many of these are more abundant in the Palaearctic region than elsewhere. Such are Scarites, Valosoma, Brachinus, Cymindis, Lebia, Chlwnius, Platynus, Harpalus, Bembecidium, Pcecilus, and Argutor. Of tropical cosmopolites, or genera found in all the tropical regions, but not in the temperate zones, there seem to be only four,—Catascopus, Coptodera, CoUtpodes, and Ca&snonia. Pheropsophus is confined to the tropics of the Old World; while Drimostoma, though widely scattered, is characteristic of the Southern Hemisphere.
The Palaearctic region has about 50 genera of Carabidae which are strictly confined to it, the most important being,—Leistvs (30 sp.), Procerus (5 sp.), Procrustes, (17 sp.), Zabrus (60 sp.), Pristonychus (42 sp.), and Ophonus (60 sp.); but it possesses a large number in common with the Nearctic region. The more remarkable of these are,—Garabus, Nebria, Amara, Cyrtonotus, Bradycellus, Anopthalmus, Celia, Cychrus, Patrobus, Elaphrus, Notiophilus, Bradytus, Callisthenus, Blethisa, and several others. Many too, though not strictly confined to the North Temperate regions, are very abundant there, with a few species isolated in remote countries, or widely scattered, often in an eccentric manner. Among these may be mentioned, Trechus (120 sp.), all North Temperate but 8, which are scattered in Java, New Caledonia, and South America; Dyschirus (127 sp.), North Temperate, with 3 or 4 species in Australia, China, and La Plata; Omaseus, (88 sp.), Steropus (90 sp.), Platysoma (114 sp.), and Pterostichus (138 sp.), are mostly North Temperate, but each has a few species in the South Temperate zone, New Zealand, Australia, Chili, and the Cape of Good Hope. Dromius (54 sp.), is about two-thirds Palaearctic, the rest of the species being scattered over the world, in Chili, North and South America, South Africa, Burmah, Ceylon, and New Zealand. The North Temperate genera Calathus and Olisihopus, have each one species in New Zealand; Percus has most of its species in South Europe, but 3 in Australia; Abax is confined to the north temperate zone, but with one species in Madagascar; while Lcemosthenes is said to have a species identically the same in South Europe and Chili. Some of these apparent anomalies may be due to wrong