368 



SEXUAL SELECTION. 



Part II. 



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 richly 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 Prionidse, 

 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. 



Fig. 10. Chalco^oma atlas. Upper figure, male (reduced) ; lower figure, female 



(nat. size). 



tricliia and Trichius, the male of the latter being more obscurely 

 coloured than the female. In Tillus elongatus the male is black, and 

 the female always, as it is believed, of a dark blue colour with a red 

 thorax. The male, also, of Orsodacna atra, as I hear from Mr. Walsh, 

 is black, the female (the so-called 0. ruficollis) having a rufous thorax. 



