Archive image from page 333 of The descent of man, and. The descent of man, and selection in relation to sex descentofmansele187301darw Year: 1873 320 SEXUAL SELECTION. [Part II. a from the left-hand one, the latter resembling in its sim- pie tapering joints the antenna? of the female. In the male the modified antenna is either swollen in the middle or angu- larly bent, or converted (fig. 3) into an elegant, and sometimes wonderfully complex, prehensile It serves, as I hear from Sir J. Lubbock, to hold the fe- male, and for this same purpose one of the two posterior legs (b) on the sa
Archive image from page 333 of The descent of man, and. The descent of man, and selection in relation to sex descentofmansele187301darw Year: 1873 320 SEXUAL SELECTION. [Part II. a from the left-hand one, the latter resembling in its sim- pie tapering joints the antenna? of the female. In the male the modified antenna is either swollen in the middle or angu- larly bent, or converted (fig. 3) into an elegant, and sometimes wonderfully complex, prehensile It serves, as I hear from Sir J. Lubbock, to hold the fe- male, and for this same purpose one of the two posterior legs (b) on the same side of the body is converted into a forceps. In an- other family the inferior or pos- terior antennae are ' curiously zig- zagged ' in the males alone. In the higher crustaceans the anterior legs form a pair of chelae or pincers, and these are gener- ally larger in the male than in the female. In many species the FlG' 3'7fromiLuCbbock))arwinii cnelse on tne opposite sides of the a. Part of right-hand anterior body are of Unequal size, the right- antenna of male, forming a 1 â â¢â T . n â prehensile organ. hand one being, as I am informed b. Posterior pair of the thoracic -i -»«- rv o t> n legs of male. by Mr. L>. fepence Bate, generally, though not invariably, the largest. This inequality is often much greater in the male than in the female. The two chelae also often differ in structure (figs. 4, 5 and 6), the smaller one resembling those of the fe- male. What advantage is gained by their inequality in size 5 See Sir J. Lubbock in 'Annals, and Mag. of Nat. Hist.' vol. xi. 1853, pis. i. and x.; and vol. xii. (1853) pi. vii. See also Lubbock in ' Transact. Ent. Soc.' vol. iv. new series, 1856-1858, p. 8. With respect to the zig- zagged antennae mentioned below, see Fritz Muller, ' Facts and Argu- ments for Darwin,' 1869, p. 40, foot-note.
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