376 SEXUAL SELECTIOX. Part II. 



that when a boy he often put the males together to see 

 them fight, and he noticed that they were much bolder 

 and fiercer than the females, as is well known to be the 

 case with the higher animals. The males would seize 

 hold of his finger, if held in front, but not so the females. 

 With many of the Lucanidse, as well as with the abo^e- 

 mentioned Leptorhynchus, the males are larger and 

 more powerful insects than the females. The two sexes 

 of Lethrus cejplialotes (one of the Lamellicorns) inhabit the 

 same burrow ; and the male has larger mandibles than 

 the female. If, during the breeding-season, a strenge 

 male attempts to enter the burrow, he is attacked ; the 

 female does not remain passive, but closes the mouth of 

 the burrow, and encourages her mate by continually 

 pushing him on from behind. The action does not 

 cease until the aggressor is killed or runs away. 65 The 

 two sexes of another lamellicorn beetle, the Ateuchus 

 cicatricosus live in pairs, and seem much attached to 

 each other; the male excites the female to roll the 

 balls of dung in which the ova are deposited ; and if 

 she is removed, he becomes much agitated. If the 

 male is removed, the female ceases all work, and as 

 M. Brulerie 66 believes, would remain on the spot until 

 she died. 



The great mandibles of the male Lucanidse are ex- 

 tremely variable both in size and structure, and in this 

 respect resemble the horns or the head and thorax 

 of many male Lamellicorns and Staphylinidse. A per- 

 fect series can be formed from the best-provided to the 

 worst-provided or degenerate males. Although the 

 mandibles of the common stag-beetle, and probably of 



65 Quoted from Fischer, in ' Diet. Class. d'Hist. Nat.' torn. s. p. 324. 



66 'Ann. Soe. Entomolog. France,' 1866, as quoted in 'Journal of 

 Travel,' by A. Murray, 186S, p. 135. 



