258 COLOR PREFERENCES 



alexis of Europe fly toward a very small bit of 

 pale blue paper lying upon the grass and stop 

 within an inch or two of it as if to settle, doubt- 

 less mistaking it for another of its own kind. 

 Plateau has observed the Small Tortoise-shell 

 (Aglais urticae) of Europe fly rapidly toward 

 a cluster of artificial flowers, and a species of 

 Pieris toward a white calla which could offer it no 

 sweets. And Jenner Wier has noticed how the 

 white butterflies settled on the variegated leaves 

 in his garden. 



Such examples as these seem to indicate that 

 butterflies may perceive color in mass, but in no 

 case indicate any further visual powers ; and since 

 the difference between the sexes is generally 

 rather one of disjDOsition of colors than of variety 

 in the colors themselves, though the latter is by 

 no means wanting, the theory of sexual selection 

 proposed by Darwin cannot be rightly claimed to 

 cover the general ground. Wallace, moreover, 

 has adduced strong reasons for doubting the value 

 of this theory, even in those animals against 

 whose powers of sight no such stricture can be 

 made, believing, as he does, that all differences 

 between the sexes can be explained from the fact 

 of the greater vigor of the male, and the intensity 



