64 BUTTERFLIES 



butterflies be thus gaily clothed ? The older 

 naturalists thought it sufficient to say that butter- 

 flies were beautiful because their beauty gave us 

 pleasure, and that it was for our enjoyment that 

 these delicate tints and gorgeous hues existed. 

 But this is clearly incorrect, for the most magnifi- 

 cent butterflies are found in parts where man but 

 seldom visits, for instance, tropical America and the 

 East Indies. The true explanations are varied 

 and not the same in all cases. 



Sexual Colours. With butterflies as with birds 

 there is often a striking difference between the 

 sexes, the male as a rule being the more gaily 

 coloured. Among birds, for instance, the cock bird 

 is often most gaily coloured ; the hen bird being more 

 soberly coloured, and indeed often plain. The 

 peacock, drake, and bird of paradise will at once 

 occur to our minds as illustrations. Mr. Wallace 

 pointed out that the sober colouring of the female 

 was explained as protective so as to escape detection 

 when sitting on eggs on an open nest. The male 

 usually taking no share in incubation had no 

 special need for protective colouring. Mr. Darwin 

 explains the specially brilliant colours of males as 

 due to what he calls sexual selection, that is, to the 

 fact of the female preferring a smart male to an 

 untidy one. So with butterflies and moths ; and if 

 we watch butterflies or birds coquetting we soon 

 convince ourselves that the males know they are 

 beautiful, and mean to show off their beauty to its 

 best advantage in the hopes of gainii|g the affection 

 of the female. 



