. The descent of man, and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings; Sexual selection in animals; Sexual dimorphism (Animals); Sex differences. INSECTS. 341 Sexual selection, which implies the possession of con- siderable perceptive powers and of strong passions, seems to have been more effective with the Lamellicorns than with any other family of beetles. With some species the males are provided with weapons for fighting; some live in pairs and show mutual aifection; many have the power of stridulating when ex- cited; many are furnished with the most e
. The descent of man, and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings; Sexual selection in animals; Sexual dimorphism (Animals); Sex differences. INSECTS. 341 Sexual selection, which implies the possession of con- siderable perceptive powers and of strong passions, seems to have been more effective with the Lamellicorns than with any other family of beetles. With some species the males are provided with weapons for fighting; some live in pairs and show mutual aifection; 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 family, which was placed by Linnaeus and Fabriciiis at the head of the order.* Stridulatmg Organs,—Beetles be- longing to many and widely distinct families possess these organs. The sound thus produced can sometimes be heard at the distance of several feet or even yards, f but it is not comparable with that made by the Orthoptera. The rasp generally con- usts of a narrow, slightly raised sur- i!ace, crossed by very fine, parallel ribs, sometimes so fine as to cause Hdescent colors, and having a very elegant appearance under the micro- ;cope. In some cases, as with Ty- L^hoeus, minute, bristly or scale-like prominences, with which the whole lurrounding surface is covered in iipproximately parallel lines, could traced passing into the ribs of the Fi^. 24. chiasognathus Gran. The transition takes place ^kiefwrfi^FrrfeS, I * Westwood, *' Modern Class.," vol. i, p. 184. fWollastoii, **0n Certain Musical Curculiouidse," "Annals and jlag. of Nat. Hist.," voL vi, 1860, p. 14. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble t
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