BEETLES THAT "BLUFF" 213 



they have been formed for some purpose ; but their 

 excessive variability in the males of the same species 

 leads to the inference that this purpose cannot be of a 

 definite nature. The horns do not show marks of friction, 

 as if used for any ordinary work. Some authors suppose 

 that as the males wander about much more than the 

 females, they require horns as a defence against their 

 enemies ; but as the horns are often blunt, they do not 

 seem well adapted for defence. The most obvious con- 

 jecture is that they are used by the males for fighting 

 together, but the males have never been observed to 

 fight, nor could Mr. Bates, after a careful examination 

 of numerous species, find any sufficient evidence, in their 

 mutilated or broken condition, of their having been thus 

 used. If the males had been habitual fighters, the size 

 of their bodies would probably have been increased 

 through sexual selection, so as to have exceeded that 

 of the females ; but Mr. Bates, after comparing the two 

 sexes in above a hundred species of the Copridae, did not 

 find any marked difference in this respect amongst well- 

 developed individuals. In Lethrus, moreover, a Beetle 

 belonging to the same great division of the Lamellicorns, 

 the males are known to fight, but are not provided with 

 horns, though their mandibles are much larger than 

 those of the female. 



" The conclusion that horns have been acquired as 

 ornaments is that which best agrees with the fact of their 

 having been so immensely, yet not fixedly, developed — 

 as shown by their extreme variability in the same species 

 This view will at first appear extremely improbable , 

 but we shall . . . find with many animals standing 

 much higher in the scale, namely, fishes, amphibians, 

 reptiles and birds, that various kinds of crests, knobs, 



