144 ORGANIC EVOLUTION 



There are a few examples of mimicry among birds. Let 

 me quote from Wallace's Darwinism a description of prob- 

 ably the best example. " More perfect cases of mimicry 

 occur between some of the dull-colored orioles in the 

 Malay Archipelago and a genus of large honey-suckers, the 

 Tropidorhynchi or 'friar-birds' (Plate 80). These latter are 

 powerful and noisy birds which go in small flocks. They 

 have long, curved, and sharp beaks, and powerful, grasping 

 claws ; and they are quite able to defend themselves, often 

 driving away crows and hawks which venture to approach 

 them too nearly. The orioles, on the other hand, are weak 

 and timid birds, and trust to concealment and to their retir- 

 ing habits to escape persecution. In each of the great 

 islands of the Austro-Malayan region there is a distinct 

 species of Tropidorhynchus, and there is always along with 

 it an oriole that exactly mimics it. All the Tropidorhynchi 

 have a patch of bare black skin around the eyes, and a ruff 

 of curious, paler, recurved feathers on the nape, whence their 

 name of friar-birds, the ruff being supposed to resemble the 

 cowl of a friar. These peculiarities are imitated in the 

 orioles by patches of feathers of corresponding colors ; 

 while the different tints of the two species in each island are 

 exactly the same. Thus in Bourru both are earthy brown ; 

 in Ceram they are both washed with yellow ochre ; in Timor 

 the under surface is pale and the throat nearly white, and 

 Mr. H. O. Forbes has recently discovered another pair in 

 the island of Timor Laut. The close resemblance of these 

 several pairs of birds, of widely different families, is quite 

 comparable with that of many of the insects already 

 described. It is so close that the preserved specimens have 

 even deceived naturalists, for, in the great French work, 



