. The descent of man, and selection in relation to sex. Evolution; Heredity; Human beings; Natural selection. CHAP. X.) INSECTS. 295. iike those on the tarsi of the Carabidae, '' and obviously for the same ; In male dragon-flies, ''the appendages at the tip of the tail are modified in an almost infinite variety of curious patterns to enable them to eml)race the neck of the ; Lastly, in the males of raany insects, the legs are furnished with pecu- liar spines, knobs or spurs; or the whole leg is bowed or thickened ; but this is by no means '>nvariably a sexual character
. The descent of man, and selection in relation to sex. Evolution; Heredity; Human beings; Natural selection. CHAP. X.) INSECTS. 295. iike those on the tarsi of the Carabidae, '' and obviously for the same ; In male dragon-flies, ''the appendages at the tip of the tail are modified in an almost infinite variety of curious patterns to enable them to eml)race the neck of the ; Lastly, in the males of raany insects, the legs are furnished with pecu- liar spines, knobs or spurs; or the whole leg is bowed or thickened ; but this is by no means '>nvariably a sexual character ; or one pair or all three pairs are elongated, sometimes to an extravagant length.^ The sexes of many species in all the orders present differences of which the meaning is not understood. One curious case is that of a beetle (fig. 10), the male of which has the left mandible much enlarged; so that the mouth is greatly distorted. In another Carabidous beetle, Eurygnathus,^ we have the case, unique as far as known to Mr. Wollaston, of the head of the fe- male being much broader and larger, though in a ^-» variable degree, than that of the male. Any num- ber of such cases could be given. They abound in the Lepidoptera: one of the most extraordi- nary is that certain male butterflies have their forelegs more or less atrophied, with the tibiae and tarsi reduced to mere rudimentary knobs. The wings, also, in the two sexes often diffe, in neuration,^^ and sometimes considerably in out- line, as in the Aricoris epitus, which v/as shown to me in the British Museum by Mr. A. Butler. The males of certain South American butterflies have tufts of hair on the margins of the wings, and horny excrescences on the discs of the pos- terior pair.^^ In several British butterflies, as shown by Mr. Wonfor, the males alone are in parts clothed with peculiar scales. The use of the bright light of the female glow-worm has been subject to much discussion. The male is feel)ly lumin- ous, as are the larv
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Keywords: ., bookcentury1800, bookdecade1870, booksubjecthumanbeings, bookyear
