210 THE COURTSHIP OF ANIMALS 



an exception to the rule that the sexes of Beetles do not 

 differ in colour. Most of these insects are large and 

 splendidly coloured. The males of the genus Pyrodes . . . 

 are generally redder but rather duller than the females, 

 the latter being coloured of a more or less splendid golden- 

 green. On the other hand, in one species the male is 

 golden-green, the female being tinted with red and purple. 

 In the genus Esmeralda the sexes differ so greatly in 

 colour that they have been ranked as distinct species : 

 in one species both are of a beautiful shining green, but 

 the male has a red thorax. On the whole, as far as I could 

 judge, the females of those Prionidae in which the sexes 

 differ are coloured more richly than the males, and this 

 does not accord with the common rule in regard to colour 

 when acquired through sexual selection." 



While there is nothing very remarkable in the two sexes 

 being coloured alike, it is certainly strange to find the female 

 more brilliantly coloured than the male. And this because 

 among the higher vertebrates, as among the birds, the 

 female exceeds in brilliance only where she also plays 

 the role of wooer instead of wooed ; leaving to the male 

 the whole responsibility of rearing the family. With 

 the Beetles the family has to rear itself, parental care 

 being limited to the right disposal of the eggs. By some 

 change in the character of the germ-plasm the females 

 may have, in these cases, acquired more " maleness," 

 more of the qualities which are answerable for the secondary 

 sexual characters of the male, or, what seems rather to 

 be the case here, a result like that which has been reached 

 in certain of the Pigeons and Parrots has been arrived 

 at. That is to say, the tendency to intensification of pig- 

 ment in the female struck out a new line, instead of follow- 

 ing that of the male. This rather rare form of sexual 



