CHAP. XV.] RECAPITULATION. 389 



Many other facts are, as it seems to me, explicable on this 

 theory. How strange it is that a bird, under the form of a wood- 

 pecker, should prey on insects on the ground ; that upland geese 

 which rarely or never swim, should possess webbed feet ; that a 

 thrush-like bird should dive and feed on sub-aquatic insects ; and 

 that a petrel should have the habits and structure fitting it for 

 the life of an auk! and so in endless other cases. But on the 

 view of each species constantly trying to increase in number, 

 with natural selection always ready to adapt the slowly varying 

 descendants of each to any unoccupied or ill-occupied place in 

 nature, these facts oease to be strange, or might even have been 

 anticipated. 



We can to a certain extent understand how it is that there is so 

 much beauty throughout nature ; for this may be largely attributed 

 to the agency of selection. That beauty, according to our sense 

 of it, is not universal, must be admitted by every one who will 

 look at some venomous snakes, at some fishes, and at certain 

 hideous bats with a distorted resemblance to the human face. 

 Sexual selection has given the most brilliant colours, elegant 

 patterns, and other ornaments to the males, and sometimes to 

 both sexes of many birds, butterflies, and other animals. With 

 birds it has often rendered the voice of the male musical to the 

 female, as well as to our ears. Flowers and fruit have been 

 rendered conspicuous by brilliant colours in contrast with the 

 green foliage, in order that the flowers may be easily seen, visited, 

 and fertilised by insects, and the seeds disseminated by birds. 

 How it comes that certain colours, sounds, and forms should give 

 pleasure to man and the lower animals, that is, how the sense of 

 beauty in its simplest form was first acquired, we do not know 

 any more than how certain odours and flavours were first rendered 

 agreeable. 



As natural selection acts by competition, it adapts and improves 

 the inhabitants of each country only in relation to their co-inhabi- 

 tants ; so that we need feel no surprise at the species of any one 

 country, although on the ordinary view supposed to have been 

 created and specially adapted for that country, being beaten and 

 supplanted by the naturalised productions from another land. 

 Nor ought we to marvel if all the contrivances in nature be not, 

 as far as we can judge, absolutely perfect, as in the case even of 

 the human eye ; or if some of them be abhorrent to our ideas of 

 fitness. We need not marvel at the sting of the bee, when used 

 against an enemy, causing the bee's own death ; at drones being 

 produced in such great numbers for one single act, and being then 

 slaughtered by their sterile sisters ; at the astonishing waste of 

 poller by our fir-trees ; at the instinctive hatred of the queen-bee 

 for her own fertile daughters; at ichneumonidae feeding within 



