Seco7idary Sexual Characters 441 



Mayer also made some experiments to test whether the females 

 show a choice in selecting the males. The male is dark or black- 

 ish ; the female reddish brown. The wings of a female were cut 

 off and glued on to the wings of a male, so that he appeared like 

 a female ; nevertheless he was accepted by a female, no aversion 

 was manifested, and the mating was normal. The converse 

 experiment was also made. The wings of a female were cut off 

 near the base and the wings of a male were glued on in their 

 place. Such females looked Hke males, yet the males mated 

 with them as with normal individuals. Clearly, then, neither the 

 coloration of the male nor of the female can be supposed to 

 have a selective value. 



Males pay no attention to males with female wings ; but will 

 pair readily with a female both of whose Avings have been cut off. 

 Even when the wings of both the male and the female have 

 been removed, pairing occurs if they are brought together. 



One series of experiments of this kind is not perhaps conclu- 

 sive, and there is great need for more experimental work along 

 these lines. 



There are many other serious objections to be urged against 

 Darwin's theory. I shall give here only a few of the more 

 important ones.^ 



In most groups of unisexual animals — and it is only such 

 that come under the theory — the number of males and fe- 

 males is approximately equal. Therefore even if we admit 

 that the most ornamented individuals are first selected, the 

 remainder of the females must pair with the less ornamented 

 males. In consequence nothing would be gained in successive 

 generations. 



It is assumed that by the selection of individual or fluctua,ting 

 differences the character of the males can be greatly changed. 

 It may be questioned if this is possible, even if rigorous selection 

 be admitted to occur. It is doubtful if anything more could be 

 accomplished in this way than to maintain the standard at a 



^ In my book on "Evolution and Adaptation" I have discussed this topic 

 more fully. 



