128 THE MEANING OF EVOLUTION 



women is so intensely attractive to man, and that 

 vigor and manliness in man are so attractive to 

 women, leads us to infer that among the lower ani- 

 mals, although of course in a vastly less degree, vigor 

 and beauty are also attractive. The weakest point of 

 the position lies in the fact that it probably presup- 

 poses a higher degree of capacity for appreciation on 

 the part of lower animals than they possess. Those 

 who deny the truth of the theory laugh at the idea 

 that a butterfly can see clearly enough and care enough 

 for what it sees to notice whether its mate has wings 

 of one type or of another. The size, number and 

 position of the spots on the wings of many butterflies 

 are so nearly constant that they cannot of themselves 

 have been entirely determined by the choice of the in- 

 sect. Yet this may not preclude the possibility of the 

 fact that, while the spots were produced through some 

 other agency, certain types of them were selected by 

 sexual preference. 



If attractive coloration is effective anywhere in the 

 animal world, it will possibly be found among the in- 

 sects, but it is especially likely to be found among the 

 birds. Very many field workers in these groups feel 

 quite sure of the value of attractiveness. When but- 

 terflies chase each other up and down, circling and 

 doubling, following each other for long distances, it 

 would certainly seem as if they were pleased with 



