342 
SEXUAL SELECTION. 
Part II. 
organs , 2 “it is astonishing,” as Mr. B. I). Walsli 3 has 
remarked, “how many different organs are worked in 
“by nature, for the seemingly insignificant object of 
“ enabling the male to grasp the female firmly.” The 
mandibles or jaws are sometimes used for this purpose ; 
thus the male Corydalis eornuius (a ueuropterous insect 
in some degree allied to the Dragon flies, &c.) has im- 
mense curved jaws, many times longer than those of the 
female ; and they are smooth instead of being toothed, 
by which means he is enabled to seize her without 
injury.'’ One of the stag-beetles of North America 
(Lucanus elaphus ) uses his jaws, which are much larger 
than those of the female, for the same purpose, but 
probably likewise for fighting. In one of the sand- wasps 
(Arnrnoph'ila) the jaws in the two sexes are closely 
alike, but are used for widely different purposes; the 
males, as Professor Westwood observes, “are exceed- 
“ ingly ardent, seizing their partners round the neck 
“ with their sickle-shaped jaws ; ” 5 whilst the females use 
5 These organs in the male often differ in closely-allied species, #i'd 
afford excellent specific characters. Hut their importance, under !l 
functional point of viow, as Mr. R. MacLaehlan lias remarked to tin • 
lias probahl.v been overrated. It has been suggested, that slight ‘111- 
ferencea in these organs would suffice to prevent the intercrossing nt 
well-marked varieties or incipient species, and would thus aid in tlici r 
development. 1'hat this can hardly be the case, we may infer from tb* 
many recorded eases (see for instance, Bronn, ‘Geschichte der Natur- 
B. ii. 1813, s. Kit; and Westwood, ‘Transact. Eat. 8oc.' vol. iii. lSi% 
p. I Do) of distinct species having been observed in union. SB- 
MacLaehlan informs me vide ‘Skit. Ent. Ztitung,’ 1867. s. 155) that 
when several species of Phryganidre. which present stiongly-prououn<’ el1 
differences of litis kind, were confined together by Dr. Aug. Mcy t ‘ r ’ 
thei/ wm'pled, and one. pair produced fertile ova. 
s ‘Tho Practical Entomologist,’ Philadelphia, vol. ii. May, 186T» 
p. 88. 
4 Mr. Walsh, ibid. p. 107. 
5 ‘Modern Classification of Insects,’ vol. ii. 1840, p. 206,205. ^ T ‘ 
Walsh, who called my attention to this double use of the jaws, s"y s 
that he has repeatedly observed this fact. 
