THE ARU ISLANDS. 373 



however, be no doubt that they exist in Am, since they occur in 

 Australia, Ternate, and the Philippines. 



The splendid large Bird-winged Butterfly, with brilliant green 

 and velvety black wings (Omithqptera poseidon) was common 

 in the woods, but flew high and was difficult to catch. I shot 

 one or two with dust shot, without their being utterly damaged. 

 I once, however, was lucky enough to find a flock of about a 

 dozen males, fluttering round and mobbing a single female. 

 They were then hovering slowly, quite close to the ground, and 

 were easily caught. 



The female had thus a large body of gaudy admirers from 

 which to make her choice. Interesting results might possibly 

 be derived from a series of experiments, in which, in the case of 

 brightly coloured and decorated butterflies, the colours should 

 be rubbed off the wings of a few amongst a number of males, or 

 painted over of a black or brown colour. It might be tested 

 whether the females would always prefer the brightly coloured 

 ones. Dark coloured butterflies might possibly have the wings 

 of the male touched up with a little colour. 



Similar experiments might be made with more chance of 

 success in the case of gaudy birds, the feathers of the cock being 

 dyed dark, or enhanced in colouring in the case of a little deco- 

 rated male. The hen might be kept in a cage between two males, 

 and it might be noted to which she gave the preference, and then, 

 whether an alteration in the colours of the plumage caused a 

 change in her inclination. If the artificial increase of colouring 

 succeeded as an experiment, then experiments might be made to 

 learn what colours, or mixture of colours, is most attractive in 

 various cases.* 



A party visited Wanumbai, Mr. Wallace's old hunting- 

 ground, in the ship's steam-pinnace. We steamed across a sort 

 of lagoon, shut in by the islands, passing on the way a large Sea 



* Mr. Tegetmeier stained some pigeons with magenta at Mr. Darwin's 

 request, but the birds were not much noticed by the others. Mr. Darwin 

 cites the case of the pied peacock, and that of the silver pheasant which 

 had its plumage spoiled, and which was then rejected by the hens. No 

 systematic experiments, however, seem to have been made on this subject 

 though they could easily be carried out in the case of birds. C. Darwin, 

 " The Descent of Man," Vol. II, pp. 118, 120, London, Murray, 1871. 



