*Ciiap. X. 
COLEOFTERA. 
377 
many oilier species, are used as efficient weapons for 
fighting, 
their 
great size can 
it is doubtful whether 
thus be accounted for. We have 
seen that with the Lucanus da - 
j pints 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 Chiasognathus 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 
Coleoptera or beetles. With some 
species the males are provided with weapons for fight- 
ing ; some live in pairs and show mutual affection ; 
Fig. 23. Chiasognathus grantii, 
reduced. Upper figure, male ; 
lower figure, female. 
