EVOLUTION 1025 



residue of the unattractive. He also pointed out that the more 

 vigorous and more attractive males would be accepted by the more 

 vigorous females which are the first to breed, and this would imply 

 a cumulative preponderance of the more vigorous and more attractive 

 types. Even earlier hatching of the young birds might be of critical 

 moment. 



As a matter of fact, definite information as to the elimination 

 of some of the males is by no means wholly lacking. Thus in dia- 

 grammatic illustration we may refer to some spiders where, as the 

 Peckhams and others have shown, the female sometimes kills a 

 suitor who does not adequately please her. That she may also kill a 

 successful suitor is immaterial, since the mating has been accom- 

 plished. (See G. W. and E. G. Peckham, Observations of Sexual 

 Selection in Spiders of the Family Attidce, Milwaukee, 1889, p. 60.) 

 It has been pointed out, however, that this devouring of the male 

 is exceptional, yet it is interesting to notice that where it does 

 occur, it is often because the male has failed to conform to the 

 frequently very subtle "rules "of sex-behaviour! 



(6) In the second place, many critics have objected to crediting 

 the female organism — ^whether bird or butterfly — with the power 

 of "choice", and while comparative psychology has not advanced 

 far enough to admit of many definite statements as to the subjective 

 aspect of animal courtship, it may be granted that there is not in 

 the "choice" of any female animal much that would correspond to 

 a human weighing of pros and cons. But the point of importance 

 is whether the mating is in any real way selective, preferential, dis- 

 criminative. It has been proved experimentally that insects as well 

 as birds may be selective in their eating : is the same true as regards 

 their mating? It appears to us that the phenomena of mating 

 recorded by Darwin, by Groos (Play of Animals, 1898), by Cunning- 

 ham [Sexual Dimorphism, 1900), by Pycraft {Courtship of Animals, 

 1913), and so on, place the reality of some measure of preferential 

 mating beyond doubt. Even if one adopts the modern view that 

 the female does not choose the "best" out of a bunch of suitors, 

 but rather remains unresponsive to the solicitations of males who 

 do not raise her emotional interest to the requisite pitch, that is 

 quite enough for the purposes of the theory; and it is in agreement 

 with Darwin's own remark about the female bird: "it is not probable 

 that she consciously deliberates: but she is most excited or 

 attracted by the most beautiful, or melodious, or gallant males". 



(c) A third objection is more serious. It is one thing to admit 

 the reality of a somewhat vague preferential mating, it is quite 

 another thing to credit the female animal with a capacity for appre- 

 ciating slight differences in decorativeness or musical talent or 

 lithesomeness. Wallace's statement of this objection is well known. 

 Referring to Darwin's four chapters in The Descent of Man, he says: 



VOL. II u 



