i. 242;

on the polygamy of the South African antelopes, i. 267; on the proportion of the sexes in _Kobus ellipsiprymnus_, i. 305; on _Bucephalus capensis_, ii. 29; on South African lizards, ii. 37; on fighting gnus, ii. 240; on the horns of rhinoceroses, ii. 248; on the fighting of lions, ii. 266; on the colours of the Cape Eland, ii. 288; on the colours of the gnu, ii. 289; on Hottentot notions of beauty, ii. 345.

SMITH, F., on the Cynipidae and Tenthredinidae, i. 314; on the relative size of the sexes of Aculeate Hymenoptera, i. 347; on the difference between the sexes of ants and bees, i. 365; on the stridulation of _Trox sabulosus_, i. 380; on the stridulation of _Mononychus pseudacori_, i. 382.

_Smynthurus luteus_, courtship of, i. 348.

SNAKES, sexual differences of, ii. 29; male, ardency of, ii. 30.

"SNARLING MUSCLES," i. 127.

SNIPE, drumming of the, ii. 63; coloration of the, ii. 226.

SNIPE, painted, sexes and young of, ii. 202.

SNIPE, solitary, assemblies of, ii. 101.

SNIPES, arrival of male before the female, i. 260; pugnacity of male, ii. 43; double moult in, ii. 80.

SNOW-GOOSE, whiteness of the, ii. 228.

SOCIAL animals, affection of, for each other, i. 76; defence of, by the males, i. 83.

SOCIABILITY, the sense of duty connected with, i. 71; impulse to, in animals, i. 79, 80; manifestations of, in man, i. 84; instinct of, in animals, i. 86.

SOCIALITY, probable, of primeval men, i. 155; influence of, on the development of the intellectual faculties,