Organic Evolution. 207 



It should be noted that the answer to the question is in 

 each case a manifestly incomplete one. For if we say that 

 these forms of beauty, floral and animal, have been selected 

 through animal preferences, there still remains behind the 

 question How and why have the preferences taken these 

 aesthetic lines ? To which I do not see my way to a satis- 

 factory answer, though some suggestions in the matter will 

 be made in a future chapter.* At present all we can say is 

 this to be conspicuous was advantageous, since it furthered 

 the mating of flowers and animals. To be diversely con- 

 spicuous was also advantageous. As Mr. Wallace says, 

 "It is probably to assist the insects in keeping to one 

 flower at a time, which is of vital importance to the per- 

 petuation of the species, that the flowers which bloom 

 intermingled at the same season are usually very distinct, 

 both in form and colour." f But conspicuousness is not 

 beauty. And the question still remains From what source 

 comes this tendency to beauty ? 



Leaving this question on one side, we may state the 

 argument in favour of sexual selection in the following 

 form : The generally admitted doctrine of mimicry involves 

 the belief that birds and other insect-eating animals have 

 delicate and particular perceptual powers. The generally 

 received doctrine of the origin of flowers involves the belief 

 that their diverse forms and markings result from the 

 selective choice of insects. There are a number of colour 

 and form peculiarities in animals that cannot be explained 

 by natural selection through elimination. There is some 

 evidence in favour of preferential mating or selective asso- 

 ciation. It is, therefore, permissible to hold, as a pro- 

 visional hypothesis, that just as the diverse forms of flowers 

 result from the preferential choice of insects, so do the 

 diverse secondary sexual characters of animals result, in 

 part at least, from the preferential choice of animals through 

 selective mating. 



If this be admitted, then the elaborate display of their 

 finery by male birds, which Mr. Wallace does admit, may 



* That on " The Emotions of Animals " (X.). t " Darwinism," p. 318. 



