Chap. X.] 



COLEOPTERA. 



357 



red thorax. On the whole, as far as I could judge, the 

 females of those PrionidaB, in which the sexes differ, are 

 colored more richly than the males ; and this does not ac- 

 cord with the common rule in regard to color when ac- 

 quired through sexual selection. 



Fig. 15.— Chalcosoma atlas. Upper figure, male (reduced) ; lower figure, female 



(natural size). 



A most remarkable distinction between the sexes of 

 many beetles is presented by the great horns which rise 

 from the head, thorax, or clypeus of the males; and in 

 some few cases from the under surface of the body. These 

 horns, in the great family of the JLamellicorns, resemble 

 those of various quadrupeds, such as stags, rhinoceroses, 

 etc., .and are wonderful both from their size and diversi- 

 fied shapes. Instead of describing them, I have given 

 figures of the males and females of some of the more re- 

 markable forms. (Figs. 15 to 19.) The females gen- 



