The Origin of Mimicry 



It is easy to understand the profit that these 

 mimics derive from their mimicry. When once 

 the disguise has been assumed we can compre- 

 hend how natural selection will tend to improve 

 it by eliminating those that mimic badly ; but it 

 seems to us that the theory fails utterly to 

 account for the origin of the likeness. 



13. Similarly, the Neo- Darwinian theory fails to 

 explain the colours of the eggs of birds laid in 

 open nests, why, for example, the eggs of the 

 accentor or hedge-sparrow are blue and those 

 of the doves are white. 



14. The theory fails to give a satisfactory ex- 

 planation of the phenomena of sexual dimorphism. 

 Why, for example, in some species of doves and 

 ducks, thesexes are alike, while in other species 

 with similar habits they differ in appearance. 



1 5. It fails to explain why the rook is black and 

 why the jackdaw has a grey neck. 



These and many other objections we shall 

 deal with more fully in the chapter on animal 

 colouration. It must suffice here to mention 

 them, and to say that our experience teaches us 

 that scarcely a single species of bird or beast 

 exists which does not display some characteristic 

 which is inexplicable on the theory that natural 

 selection, acting on small variations, is the one 

 and only cause of organic evolution. 



