Chap. X. 



Coleoptera. 



295 



which the sexes differ, are coloured more richly than the males, 

 and this does not accord with the common rule ill regard to 

 colour, 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 those of various quadrupeds, such 

 as stags, rhinoceroses, &c, and are wonderful both from their 

 size and diversified shapes. Instead of describing them, I have 

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

 markable forms. (Figs. 16 to 20.) The females generally ex- 

 hibit rudiments of the horns in the form of small knobs or 

 ridges ; but some are destitute of even the slightest rudiment. 

 On the other hand, the horns are nearly as well developed in the 

 female as in the male of Phanceus lancifer ; and only a little less 

 well developed in the females of some other species of this genus 

 and of Copris. I am informed by Mr. Bates that the horns do 

 not differ in any manner corresponding with the more important 

 characteristic differences between the several subdivisions of the 

 family : thus within the same section of the genus Onthophagus, 

 there are species which have a single horn, and others which 

 have two- 



*H 



16. Chalcosoma atlas. 



Upper figure, male (r due d) ; lov??r figure, female 

 (nat. size). 



