A MALAYAN FOREST, WITH ITS CHARACTERISTIC BIRDS.
Among the Amphibia, toads and frogs of the genera Micrhyla, Kalophrynus, Ansonia, and Pseudobufo, are peculiar: while the Oriental Megalophrys, Ixalus, Rhacophorus, and Hylorana are abundant and characteristic.
Fishes.—The fresh-water fishes of the Malay archipelago have been so well collected and examined by the Dutch naturalists, that they offer valuable indications of zoo-geographical affinity; and they particularly well exhibit the sharply defined limits of the region, a large number of Oriental and even Ethiopian genera extending eastward as far as Java and Borneo, but very rarely indeed sending a single species further east, to Celebes or the Moluccas. Thirteen families of fresh-water fishes are found in the Indo-Malay sub-region. Of these the Scienidæ and Symbranchidæ have mostly a wide range in the tropics. Ophiocephalidæ are exclusively Oriental, reaching Borneo and the Philippine islands. The Mastacembelidæ are also Oriental, but one species is found as far as Ceram. Of the Nandidæ, 3 genera range over the whole region. The Labyrinthici extend from Africa through the Oriental region to Amboyna, The single species constituting the family Luciocephalidæ is confined to Borneo and the small islands of Biliton and Banca. Of the extensive family Siluridæ 17 genera are Oriental and Malayan, and 11 are Malayan exclusively; and not one of these appears to pass beyond the limits of the sub-region. The Cyprinidæ offer an equally striking example, 23 genera ranging eastward to Java and Borneo and not one beyond; 14 of these being exclusively Malayan. It must be remembered that this is not from any want of knowledge of the countries farther east, as extensive collections have also been made in Celebes, the Moluccas, and Timor; so that the facts of distribution of fresh-water fishes come, most unexpectedly, to fortify that division of the archipelago into two primary regions, which was founded on a consideration of mammalia and birds only.
Insects.—Few countries in the world can present a richer and more varied series of insects than the Indo-Malay islands, and we can only here notice a few of their more striking peculiarities and more salient features.
The butterflies of this sub-region, according to the best estimate that can be formed, amount to about 650 described species, a number that will yet, no doubt, be very considerably increased. The genera which appear to be peculiar to it are Erites (Satyridæ); Zeuxidia (Morphidæ); Amnosia, Xanthotænia, and Tanæcia (Nymphalidæ). The groups which are most characteristic of the region, either from their abundance in individuals or species, or from their size and beauty, are—the rich dark-coloured Euplæa; the large semi-transparent Hestia; the plain-coloured Mycalesis, which replace our meadow-brown butterflies (Hipparchia); the curious Elymnias, which often closely resemble Euplæas; the large and handsome Thamantis and Zeuxidia, which take the place of the giant Morphos of South America; the Cethosia, of the brightest red, and marked with a curious zigzag pattern; the velvety and blue-glossed Terinos; the pale and delicately-streaked Cyrestis; the thick-bodied and boldly coloured Adolias; the small wine-coloured Taxila; the fine blue Amblypodia; the beautiful Thyca, elegantly marked underneath with red and yellow, which represent our common white butterflies and are almost equally abundant; the pale blue Eronia, and the large red-tipped Iphias. The genus Papilio is represented by a variety of fine groups; the large Ornithoptera, with satiny yellow under-wings; the superb green-marked "brookeana;" the "paradoxa" group, often closely resembling the Euplæas that abound in the same district; the "paris" group richly dusted with golden-green specks; the "helenus" group with wide-spreading black and white wings; the black and crimson "polydorus" group; the "memnon" group, of the largest size and richly-varied colours; and the "eurypilus" group, elegantly banded or spotted with blue or green: all these are so abundant that some of them are met with in every walk, and are a constant delight to the naturalist who has the privilege of observing them in their native haunts.
The Coleoptera are far less prominent and require to be carefully sought after; but they then well repay the collector. As affording some measure of the productiveness of the tropics in insect life it will not be out of place to give a few notes of the number of species collected by myself in some of the best localities. At Singapore 300 species of Coleoptera were collected in 15 days, and in a month the number had increased to 520; of which 100 were Longicorns and 140 Rhyncophora. At Sarawak in Borneo I obtained 400 species in 15 days, and 600 in a month. In two months this number had increased to about 850, and in three months to 1,000 species. This was the most prolific spot I ever collected in, especially for Longicorns which formed about one-fifth of all the species of beetles. In the Aru Islands in one month, I obtained only 235 species of Coleoptera, and about 600 species of insects of all orders; and this may be taken as a fair average, in localities where no specially favourable conditions existed. On the average 40 to 60 species of Coleoptera would be a good day's collecting; 70 exceptionally good; while the largest number ever obtained in one day was 95, and the majority of these would be very minute insects. It must be remembered, however, that many very common species were passed over, yet had every species met with been collected, not much more than 100 species would ever have been obtained in one day's collecting of four or five hours. These details may afford an interesting standard of comparison for collectors in other parts of the world.
Of Cicindelidæ the most peculiarly Malayan form is Therates, found always on leaves in the forests in the same localities as the more widely spread Collyris. Five genera of this family are Indo-Malayan.
The Carabidæ, though sufficiently plentiful, are mostly of small size, and not conspicuous in any way. But there is one striking exception in the purely Malayan genus Mormolyce, the largest and most remarkable of the whole family. It is nocturnal, resting during the days on the under side of large boleti in the virgin forest. Pericallus and Catascopus are among the few genera which are at all brillantly coloured.
Buprestidæ are abundant, and very gay; the genus Belionota being perhaps one of the most conspicuous and characteristic. The giant Catoxantha is, however, the most peculiar, though comparatively scarce. Chrysochroa and Chalcophora are also abundant and characteristic. Out of the 41 Oriental genera 21 are Malayan, and 10 of these are not found in the other sub-regions.