. The descent of man, and selection in relation to sex. Evolution; Heredity; Human beings; Natural selection. CHAP. X.] COLEOPTERA, 3i9 If the male is removed the female ceases all work, and, as M. Brulerie ''^ believes, would remain on the s?me spot until she died. The great mandibles of the male Lucanidse are extremely variable lx)th in size and structure, and in this re- spect resemble the horns on the head and thorax of many male Lamelli- corns and Staphylinidse. A perfect series can be formed from the best- provided to the worst-provided or de- generate males. Although the mandi- bles of
. The descent of man, and selection in relation to sex. Evolution; Heredity; Human beings; Natural selection. CHAP. X.] COLEOPTERA, 3i9 If the male is removed the female ceases all work, and, as M. Brulerie ''^ believes, would remain on the s?me spot until she died. The great mandibles of the male Lucanidse are extremely variable lx)th in size and structure, and in this re- spect resemble the horns on the head and thorax of many male Lamelli- corns and Staphylinidse. A perfect series can be formed from the best- provided to the worst-provided or de- generate males. Although the mandi- bles of the common stag-beetle, and probably of many other species, are used as efficient weapons for fighting, it is doubtful whether their great size can thus be accounted for. We have seen that they are used by the Lucanus elaphus of North America for seizing the female. As they are so conspic- uous and so elegantly branched, and as owing to their great length they are not well adapted for pinching, the sus- picion has crossed my mind that they may in addition serve as an ornament, like the horns on the head and thorax of the various species above described. The male Chiasognathus grantii of South Chile—a splendid beetle belong- ing to the same family—has enormous- ly developed mandibles (fig. 24) ; he is bold and pugnacious; when threat- ened he faces round, opens his great jaws, and at the same time stridulates loudly. But the mandibles were not strong enough to pinch my finger so as to cause actual pain. Sexual selection, which implies the JJwerlfgure^^rmaii;^"''''"^'^'* possession of considerable perceptive powers and of strong passions, seems to have been more effec- tive with the Lamellicorns than with any other family ot beetles. With some species the males are provided with weap*. Fig. 24.—ChiasognatVius grantfl, '* " Ann. Soc. Entomolog. ; 1866. as quoted in " Journal ot TraveV by A. MuP |Mgr> x868, p. Please note that these im
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