. The descent of man : and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings. 298 THE DESCENT OF MAN. whether their great size can thus be accounted for. We have seen that they are used by the Lucanus elaphus of N. America for seiz- ing 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 suspicion 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 Gran
. The descent of man : and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings. 298 THE DESCENT OF MAN. whether their great size can thus be accounted for. We have seen that they are used by the Lucanus elaphus of N. America for seiz- ing 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 suspicion 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 S. Chile —a splendid beetle belonging to the same family—has enormously developed mandibles (iig. 24); he is bold and pugna- cious; when threatened he faces round, opens his great jaws, and at the same time stridulates loudly. But the mandi- bles were not strong enough to pinch my linger so as to cause actual pain. Sexual selection, which implies the pos- session of considerable perceptive powers and of strong passions, seems to have been more effective with the Lamellicorna than with any other family of beetles. With bome species the males are provided J p \ with weapons for fighting; some live in ^ if ^ I pairs and show mutual affection; many have the power of stridulating when ex- cited; many are furnished with the most extraordinary horns, apparently for the sake of ornament; and some, which are diurnal in their habits, are gorgeously colored. Lastly, several of the largest beetles in the world belong to this fam- ily, which was placed by Linnaeus and Fabricius at the head of the Order.^^. Fig". 24. Chiasognathus Stridulating organs.—Beetles belonging to many and widely distinct families pos- sess these organs. The sound thus pro- grantii, reduced, per figrire, male; er figure, female. Up- duced can sometimes be heard at the dis- low- tance of several feet or even yards,''^ but it is not comparable with that made by the Orthoptera. The rasp generally consi
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Keywords: ., bookcentury1800, bookdecade1870, booksubjecthumanbeings, bookyear
