Chap. X. 



COLEOPTERA. 



377 



many other species, are used as efficient weapons for 

 fighting, it is doubtful whether their great size can 

 thus be accounted for. We have 

 seen that with the Lueanus ela- 

 plms of N. America they are used 

 for seizing the female, As they 

 are so conspicuous and so ele- 

 gantly branched, the suspicion 

 has sometimes crossed my mind 

 that they may be serviceable to 

 the males as an ornament, in the 

 same manner as the horns on the 

 head and thorax of the various 

 above described species. The 

 male Chiasoc/nathus grantii of S. 

 Chile — a splendid beetle belong- 

 ing to the same family — has enor- 

 mously-developed mandibles (fig. 

 23) ; he is bold and pugnacious ; 

 when threatened on any side he 

 faces round, opening his great 

 jaws, and at the same time stridu- 

 lating loudly ; but the mandibles 

 were not strong enough to pinch 

 my finger so as to cause actual 

 pain. 



Sexual selection, which implies 

 the possession of considerable per- 

 ceptive powers and of strong pas- 

 sions, seems to have been more 

 effective with the Lamellicorns 

 than with any other family of the 

 Ooleoptera or beetles. With some 

 species the males are provided with weapons for fight- 

 ing ; some live in pairs and show mutual affection ; 



Fig. 23. Chiasopnathus grantii, 

 reduced. Upper figure, male ; 

 lower figure, female. 



