按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
tain； and North Australia。
It was in the Moluccas that I first discovered undoubted cases of 〃mimicry〃 among birds； and these are so curious that I must briefly describe them。 It will be as well； however； first to explain what is meant by mimicry in natural history。 At page 205 of the first volume of this work； I have described a butterfly which； when at rest； so closely resembles a dead leaf； that it thereby escape the attacks of its enemies。 This is termed a 〃protective resemblance。〃 If however the butterfly； being itself savoury morsel to birds； had closely resembled another butterfly which was disagreeable to birds； and therefore never eaten by them； it would be as well protected as if it resembled a leaf； and this is what has been happily termed 〃mimicry〃 by Mr。 Bates； who first discovered the object of these curious external imitations of one insect by another belonging to a distinct genus or family； and sometimes even to a distinct order。 The clear… winged moth which resemble wasps and hornets are the best examples of 〃mimicry〃 in our own country。
For a long time all the known cases of exact resemblance of one creature to quite a different one were confined to insects； and it was therefore with great pleasure that I discovered in the island of Bouru two birds which I constantly mistook for each other； and which yet belonged to two distinct and somewhat distant families。 One of these is a honeysucker named Tropidorhynchus bouruensis； and the other a kind of oriole； which has been called Mimeta bouruensis。 The oriole resembles the honeysucker in the following particulars： the upper and under surfaces of the two birds are exactly of the same tints of dark and light brown； the Tropidorhynchus has a large bare black patch round the eyes； this is copied in the Mimeta by a patch of black feathers。 The top of the head of the Tropidorhynchus has a scaly appearance from the narrow scale…formed feathers； which are imitated by the broader feathers of the Mimeta having a dusky line down each。 The Tropidorhynchus has a pale ruff formed of curious recurved feathers on the nape （which has given the whole genus the name of Friar birds）； this is represented in the Mimeta by a pale band in the same position。 Lastly； the bill of the Tropidorhynchus is raised into a protuberant keel at the base； and the Mimeta has the same character； although it is not a common one in the genus。 The result is； that on a superficial examination the birds are identical； although they leave important structural differences； and cannot be placed near each other in any natural arrangement。
In the adjacent island of Ceram we find very distinct species of both these genera； and； strange to say； these resemble each other quite as closely as do those of Bouru The Tropidorhynchus subcornutus is of an earthy brown colour； washed with ochreish yellow； with bare orbits； dusky： cheeks； and the usual recurved nape…ruff： The Mimeta forsteni which accompanies it； is absolutely identical in the tints of every part of the body； and the details are copied just as minutely as in the former species。
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 Ornithopteraepriamus； 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 NymphalidaeDiadema 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 in