412 THE ZOOLOGIST. 



the display of the male solely as a sign of vigour and health, and 

 thereby attractive to the female, and finally denies any aesthetic 

 sense to the female. He says : — " We have thus no reason for 

 imputing to her any of those aesthetic emotions which are excited 

 in us by the beauty of form, colour, &c, or the still more im- 

 probable aesthetic tastes which would cause her to choose a mate 

 on account of minute differences in their forms, colours, &c." 

 Here I am unable to follow him. As natural selection continually 

 acts for the future good of a species, it is evident that in order to 

 attain this end a healthy female is as essential as a healthy male, 

 and therefore those females which are first ready to breed, and 

 before whom the males display their plumage, must be in a 

 healthy and fit condition ; if the reverse were the case, and an 

 unhealthy female had as great a chance of securing a mate as a 

 healthy one, then such a theory as Mr. Wallace puts forward 

 would become untenable. But the evidence in support of such 

 a supposition is strong. The females of all the migratory species 

 arrive after the males, the interval between the sexes varying in 

 different species. The arrival of the females is spread over some 

 days ; at first they come sparingly, but later increase rapidly. 

 Among the Ducks, a female desires to choose a mate ; to her all 

 the drakes pay homage, regardless of other females round, who in 

 their turn are apparently disinterested spectators of the display 

 of the males. Natural selection therefore has probably im- 

 planted in the female a faculty whereby she becomes conscious 

 of the fact that she is in a healthy and fit condition to breed. 

 According, then, to Mr. Wallace, in order to obtain the same 

 result attained in the female, natural selection has caused the 

 males to go through an elaborate display, and in addition has 

 developed in the female the power of selecting the most vigorous 

 male. Surely this is a fallacy. It would have been a far more 

 simple process, and one more in keeping with the working of 

 natural selection, as we know it, if the same power developed in 

 the female had also been developed in the male ; and supposing 

 such were the case, then, no explanation is afforded by such a 

 theory for the display. There is another objection directly 

 arising out of this theory, which alone makes it almost incon- 

 ceivable that colours, &c, could have been developed in this 

 manner. It is this : that if all plumes, colours, song, and form 



