SEXUAL SELECTION 



363 



is astonisliing, " as Mr. B. D. Walsli" 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 cornutua 

 (a neuropterous insect in some degree allied to the Dragon- 

 flies, etc.) has immense curved jaws, many times longer 

 than those of the female; and they are smooth instead of 

 being toothed, so that he is thus enabled to seize her with- 

 out 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 pur- 

 pose, but probably likewise for 

 fighting. In one of the sand- 

 wasps {Ammophila) the jaws in 

 the two sexes are closely alike, 

 but are used for widely different 

 purposes: the males, as Prof. 

 Westwood observes, "are exceed- 

 ingly ardent, seizing their partners 

 round the neck with their sickle- 

 shaped jaws;" ' while the females 

 use their organs for burrowing 

 in sand-banks and making their 

 nests. 



The tarsi of the front legs are mo, 9.-crabro cribrarius. trppet 

 dilated in many male beetles, or^^^' ""*'"' ^°^^' ^^""^' f"'"^'"- 

 are furnished with broad cushions of hairs; and in many 

 genera of water-beetles they are armed with a round, fiat 



Bnt. Soc," vol. iii., 1842, p. 195) of distinct species having been observed in 

 union. Mr. MacLacUan informs me (vide "Stett. Ent. Zeitung," 1867, s. 155) 

 that when several species of Phryganidse, which present strongly pronounced 

 differences of this kind, were confined together by Dr. Aug. Meyer, they 

 coupled, and one pair produced fertile ova. 



* "The Practical Entomologist," Philadelphia, vol. ii., May, IBS'?, p. 88. 



4 Mr. Walsh, ibid., p. 107. 



» "Modern Classification of Insects," vol. ii., 1840, pp. 205, 206. Mr. 

 Walsh, who called my attention to the double use of the jaws, says that 

 he has repeatedly observed this fact. 



