1 8 The Descent of Man 



liave often seen, before poultry or even pigs ' (vol. ii. p. 86). 

 Again, as to the brilliant Rupicola crocea, Sir R. Schomburgk 

 says : ' A male was capering to the apparent delight of 

 several others ' (vol. ii. p. 87). 



From the fact of ' display ' Mr. Darwin concludes that ' it 

 is obviously probable that the females appreciate the beauty 

 of their suitors' (vol. ii. p. 111). Our author, however, only 

 ventures to call it ' probable,' and he significantly adds : ' It 

 is, however, difficult to obtain direct evidence of their capacity 

 to appreciate beauty.' And again he says of the hen bird : 

 ' It is not probable that she consciously deliberates ; but she 

 is most excited or attracted by the most beautiful, or melo- 

 dious, or gallant males' (vol. ii. p. 123). No doubt the 

 plumage, song, etc., all play their parts in aiding the various 

 processes of life ; but to stimulate the sexual instinct, even 

 supposing this to be the object, is one thing — to supply the 

 occasion for the exercise of a power of choice is quite another. 

 Certainly we cannot admit what Mr. Darwin affirms (vol. ii. 

 p. 124), that an ' even occasional preference by the female of 

 the more attractive males would almost certainly lead to 

 their modification.' 



A singular instance is given by Mr. Darwin (vol. ii. p. Ill) 

 in support of his view, on the authority of Mr. J. Weir. It is 

 that of a bullfinch which constantly attacked a reed-bunting, 

 newly put into the aviary ; and this attack is attributed to a 

 sort of jealousy on the part of the blackheaded bullfinch of 

 the black head of the bunting. But the buUfinch could 

 hardly be aware of the colour of the top of its own head ! 



Mr Wallace accounts for the brilliant colours of cater- 

 pillars and many birds in another way. The caterpillars 

 which are distasteful, must have gained if ' some outward 

 sign indicated to their would-be destroyer that its prey was a 

 disgusting morsel.' As to birds, he believes that brilliance of 

 plumage is developed where not hurtful, and that the gener- 



