SEXUAL SELECTION 105 



way the attitude of the sexes to each other. 7 Even 

 the complete absence of wings failed to produce any 

 impression; at the same time it was shown by experi- 

 ments made on those butterflies and on the Porthe- 

 tria, that the males were attracted by a certain odour 

 emanating from the females. 



There have been other objections to the idea of 

 sexual selection. T. H. Morgan 8 lists as many as 

 twenty, the most important of which we have already 

 mentioned. The strength of those objections com- 

 pels us to conclude that a different explanation must 

 be found for the majority of cases in point. Dar- 

 win's theory rendered a signal service, as it offered a 

 natural explanation and excluded all finalist consider- 

 ations. It retained its prestige long enough to ac- 

 custom thinkers to accept only explanations of this 

 nature. It mav now make room for some other the- 

 ory more in conformity with experimental data and 

 taking into account the discoveries made since Dar- 

 win's time. 



Many solutions have been offered for this prob- 

 lem. Certain naturalists have expressed the opinion 

 that the colouring of males is a means of identifica- 

 tion, but we fail to see why males alone should need 

 it; it would seem, on the contrary, as though the fe- 

 males, being generally passive and sought by the 



T Cited by Kellogg, Darwinism To-day, p. 122. 



s T. H. Morgan. Evolution and Adaptation, pp. 167-221. 



