112 HEREDITY AND SEX 



red and the other gray, the difference would have been 

 put down to such selection. There are also cases like 

 the phalarope, shown in Fig. 58, where the female is 

 more highly ornamented than the male. In fact, for 

 these cases, Darwin supposed that the males select 

 the females ; and in support of this view he points out 

 that the females are more active, while the male con- 

 cerns himself with the brooding of the eggs. In some 

 of the marine copepods female ornamentation is car- 

 ried to even a higher point. In Calocalanus plumosus 

 the female has one of the tail setae drawn out into a long 

 feather-like structure (Fig. 59). In another species, 

 C. parva, all eight setae of the tail of the female are 

 feather-like (Fig. 59, B), while the male (Fig. 59, C) 

 lacks entirely these " ornaments." 



In some butterflies also, two, three, or more types of 

 females are known, but only one male type. I shall 

 have occasion later to consider this case. 



COURTSHIP 



The theory of sexual selection hinges in the first 

 place on whether the female chooses amongst her 

 suitors. 



It has been objected that the theory is anthropo- 

 morphic it ascribes to beetles, butterflies, and birds 

 the highly developed esthetic sense of man. It has 

 been objected that the theory leaves unexplained the 

 development of this esthetic sense itself, for unless the 

 female kept in advance of the male it is not self-evident 

 why she should go on selecting the more highly orna- 

 mented. If she has advanced esthetically, what has 

 brought it about? In answer to this last question 



