815 Mimetie Analogy, 



eyes of the oriole, and even the very peculiar ruff of recurved 

 feathers on the nape of the former, has its general effect imi- 

 tated by a collar of pale colour in the latter. The under and 

 upper surfaces of the two birds are as near as possible of the 

 same tint respectively, and, stranger still, the oriole has 

 closely copied the mode of flight and voice of its model, so 

 that in a state of nature the two birds are practically undis- 

 tinguishable." 



" This curious instance," states Mr. Wallace, " does not 

 stand alone, for in the adjacent island of Oeram, two allied but 

 very distinct species resemble each other with equal accuracy.'" 



With regard to the object of this imitation, Mr. Wallace 

 proceeds : — " In the case of insects it seems probable that it is 

 the odour or the taste of the imitated species which is unpala- 

 table to insect-eating birds ; or, in other cases, like the clear- 

 winged moths, which mimic Hymenoptera, the species mi- 

 micked are armed with a sting. In birds, it is evidently the 

 bravest, strongest, and best armed groups should be the sub- 

 jects of mimicry, and the weakest and most defenceless which 

 should obtain some advantage by imitating them. 



" Returning to the oriole and the honeysucker, we have 

 to observe that the former is a smaller, weaker, less active, 

 less noisy, and less pugnacious bird. The feet have a less 

 powerful grasp, and the bill is less acute. The latter has a 

 great variety of loud and piercing notes, which bring its com- 

 panions to the rescue in time of danger. And I have observed 

 them drive away crows, and even hawks, which had ventured 

 to perch on a tree where two or three of them were feeding. 



" The honeysucker knows how to take care of himself, and 

 make himself both respected and feared. It would, therefore, 

 evidently be to the advantage of the more defenceless oriole 

 to be mistaken for him. 



" In this instance, as in most others, the imitation is far 

 closer in the living bird than in the dead specimens. This is 

 a far more satisfactory case of mimicry than any of those 

 which I have before alluded to as occurring amoug birds. We 

 have here two species, each confined to single islands, and 

 each accurately imitated by a bird of a distinct family, with 

 which it has no direct affinities. I therefore cannot doubt 

 that this is a true case of mimicking exactly analogous to 

 that so common among insects." 



The most remarkable cases of mimetic analogy with which 

 we are acquainted are those found amongst the butterflies ot 

 the valley of the Amazon. These cases have been invcsi igati il 

 with great care by Mr. H. W. Bates, and the results published 

 in the twenty-third volume of the Transactions of the Linnean 

 Society. 



