292 



THE DESCENT OP MAN. 



tion, are generally redder but rather duller than the females, the 

 latter being colored 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 color that they have been ranked 

 as distinct species; in one species both are of a beautiful shin- 

 ing green, but the male has a red thorax. On the whole, as far 





Fig. 16. Chalcosoma atlas. Upper figure, male (reduced); lower 

 fig'ure, female (natural size). 



as I could judge, the females of those Prionidae, in which the sexe3 

 differ, are colored more richly than the males, and this does not 

 accord with the common rule in regard to color, when acquired 

 through sexual selection. 



A most remarkable distinction between the sexes of many 

 beetles is presented by the great horns which rise from the head, 

 thorax, and clypeus of the males; and in some few cases from 

 the under surface of the body. These horns, in the great family 

 of the Lamellicorns, resemble these of various quadrupeds, such 



R. Trimen and Waterhouse, jun., inform me of two Lamellicorns, 

 viz., a- Peritrichia and Trichius, the male of the latter being more 

 obscurely colored than the female. In Tillus elongatus the male is 

 black, and the female always, as it is believed, of a dark blue color, 

 with a red thorax. The male, also, of Orsodacna atra, as I hear from 

 Mr. Walsh, is black, the female (the so-called O. ruflcollis) having a 

 rufous thorax. 



