SEXUAL SELECTION— NESTING OF BIRDS. 231 



explained if we look back to the past history of 

 those species, as is reflected in allied forms. 



Mr. Allen suggests that the only function of 

 concealment is that of the eggs — not the sitting 

 female. If this is admitted by a naturalist who 

 does not appear to believe in Darwin's brilliant 

 theory of Sexual Selection, his unbelief seems to the 

 present writer to be condemned by his own state- 

 ments. If the female bird be not kept dull and 

 sombre in colour by such a vitally important 

 function as the hatching of the eggs and the rear- 

 ing of the young in safety, why, it may be asked, is 

 she not equally as brilliant in colour as her mate ? 

 and if Sexual Selection does not give to him his 

 brilliant dress, whence the gaiety of his attire ? I 

 hold with much of what Mr. Allen has to say 

 respecting the colour of eggs ; but I also insist that 

 this colour is to a very large extent correlated with 

 the plumage of the female. It seems probable that 

 the colouring matter on birds' eggs is, or was at 

 some more or less remote period, influenced by 

 surrounding colours during the bird's period of 

 conception. We well know that eggs closely 

 resemble the colour of surrounding objects — the 

 dominant colour of a bird's surroundings and haunts 

 — greens with arboreal birds, sand colour and browns 



