MIMETIC ANALOGY. 47 



" 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 power- 

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

 variety of loud and piercing notes, which bring its companions 

 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 among 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 which have 

 come to our knowledge are those of certain butterflies found 

 in the valley of the Amazon. Mr. H. W. Bates investigated 

 these cases most carefully, and recorded the results in the 

 Transactions of the Linnaean Society, vol. xxiii., from which 

 we give a summary of his observations. 



Among the numerous butterflies of this region are various 

 genera and species belonging to the family of Heliconidse. 

 They thrive and flourish although of feeble structure and slow 

 in flight, and apparently without any means of defence in 

 districts abounding with insect- eating birds, and are so 

 numerous that the pathways of the forests are quite gay with 

 the myriads that fly about clothed in bright orange, yellow, 

 red, blue, and black. Some of the species are in the habit of 

 assembling in small parties like our gnats, or by twos and 

 threes, to sport together, and perform a kind of mazy dance. 

 The sport generally begins with a single pair, which advance, 



