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SEXUAL SELECTION. 
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 Lucanicke, as well as with the above- 
mentioned Leptorhynchus, the males are larger and 
more powerful insects than the females. The two sexes 
of Lethrus cejphalotes (one of the Lamellicorns) inhabit the 
same burrow; and the male has larger mandibles than 
the female. If, during the breeding-season, a strange 
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 on the head and thorax 
of many male Lamellicorns and Staphylinidae. 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.’ tom. x. p. 324. 
66 ‘ Ann. Soc. Entomolog. France,’ 1866, as quoted in ‘ Journal of 
Travel,’ by A. Murray, 1868, p. 135. 
