We have two kinds of evidence to tell us which bird in this case is the model, and which the copy. The honeysuckers are coloured in a manner which is very general in the whole family to which they belong, while the orioles seem to have departed from the gay yellow tints so common among their allies. We should therefore conclude that it is the latter who mimic the former. If so, however, they must derive some advantage from the imitation, and as they are certainly weak birds, with small feet and claws, they may require it. Now the Tropidorhynchi are very strong and active birds, having powerful grasping claws, and long, curved, sharp beaks. They assemble together in groups and small flocks, and they haw a very loud bawling note which can be heard at a great distance, and serves to collect a number together in time of danger. They are very plentiful and very pugnacious, frequently driving away crows and even hawks, which perch on a tree where a few of them are assembled. It is very probable, therefore, that the smaller birds of prey have learnt to respect these birds and leave them alone, and it may thus be a great advantage for the weaker and less courageous Mimetas to be mistaken for them. This being case, the laws of Variation and Survival of the Fittest, will suffice to explain how the resemblance has been brought about, without supposing any voluntary action on the part of the birds themselves; and those who have read Mr. Darwin's "Origin of Species" will have no difficulty in comprehending the whole process.
The insects of the Moluccas are pre-eminently beautiful, even when compared with the varied and beautiful productions of other parts of the Archipelago. The grand bird-winged butterflies (Ornithoptera) here reach their maximum of size and beauty, and many of the Papilios, Pieridae Danaidae, and Nymphalidae are equally preeminent. There is, perhaps, no island in the world so small as Amboyna where so many grand insects are to be found.
Here are three of the very finest Ornithopterae--priamus, helena, and remiss; three of the handsomest and largest Papilios--ulysses, deiphobus, and gambrisius; one of the handsomest Pieridae, Iphias leucippe; the largest of the Danaidae, Hestia idea; and two unusually large and handsome Nymphalidae--Diadema pandarus, and Charaxes euryalus. Among its beetles are the extraordinary Euchirus longimanus, whose enormous legs spread over a space of eight inches, and an unusual number of large and handsome Longicorns, Anthribidae, and Buprestidae.
The beetles figured on the plate as characteristic of the Moluccas are: 1. A small specimen of the Euchirus longimanus, or Long-armed Chafer, which has been already mentioned in the account of my residence at Amboyna (Chapter XX.). The female has the fore legs of moderate length. 2. A fine weevil, (an undescribed species of Eupholus,) of rich blue and emerald green colours, banded with black. It is a native of Ceram and Goram, and is found on foliage. 3. A female of Xenocerus semiluctuosus, one of the Anthribidae of delicate silky white and black colours.
It is abundant on fallen trunks and stumps in Ceram and Amboyna.
4. An undescribed species of Xenocerus; a male, with very long and curious antenna, and elegant black and white markings. It is found on fallen trunks in Batchian. 5. An undescribed species of Arachnobas, a curious genus of weevils peculiar to the Moluccas and New Guinea, and remarkable for their long legs, and their habit of often sitting on leaves, and turning rapidly round the edge to the under-surface when disturbed. It was found in Gilolo.
All these insects are represented of the natural size.
Like the birds, the insects of the Moluccas show a decided affinity with those of New Guinea rather than with the productions of the great western islands of the Archipelago, but the difference in form and structure between the productions of the east and west is not nearly so marked here as in birds. This is probably due to the more immediate dependence of insects on climate and vegetation, and the greater facilities for their distribution in the varied stages of egg, pupa, and perfect insect. This has led to a general uniformity in the insect-life of the whole Archipelago, in accordance with the general uniformity of its climate and vegetation; while on the other hand the great susceptibility of the insect organization to the action of external conditions has led to infinite detailed modifications of form and colour, which have in many cases given a considerable diversity to the productions of adjacent islands.
Owing to the great preponderance among the birds, of parrots, pigeons, kingfishers, and sunbirds, almost all of gay or delicate colours, and many adorned with the most gorgeous plumage, and to the numbers of very large and showy butterflies which are almost everywhere to be met with, the forests of the Moluccas offer to the naturalist a very striking example of the luxuriance and beauty of animal life in the tropics. Yet the almost entire absence of Mammalia, and of such wide-spread groups of birds as woodpeckers, thrushes, jays, tits, and pheasants, must convince him that he is in a part of the world which has, in reality but little in common with the great Asiatic continent, although an unbroken chain of islands seems to link them to it.
