HYELAPIIUS 



INDEX. 



INSECTIVORA. 



651 



Byelaphus porcinus, 546. 



Hygrogonus, 345. 



Hyla, singing species of, 350. 



Hylobates, absence of the thumb in, 51 ; 

 upright progression of some species 

 of, 52 ; maternal affection in a. 

 70; direction of the hair on the 

 arms of species of, 151 ; females of, 

 less hairy below than males, 558. 



— — agilis, 51 ; hair on the arms of, 

 151 ; musical voice of the, 527 ; 

 superciliary ridge of, 558 ; voice of. 

 567. 



hooloch, sexual difference of 



colour in, 537. 



— — lar, 51 ; hair on the arms of, 

 151. 



leucisciis, 51 ; song of, 568. 



syndactylus, 51; laryngeal sac 



of, 527. 



Hylophila prasinana, 308. 



Hymenoptera, 291 ; large size of the 

 cerebral ganglia in, 54 ; classifica- 

 tion of, 148 ; sexual differences in 

 the wings of, 277 ; aculeate, rela- 

 tive size of the sexes of, 279. 



Hymenopteron, parasitic, with a 

 sedentary male, 221. 



Hyomoschus aquativs, 547. 



Hyperytkra, proportion of the sexes 

 in, 251. 



Hypogyrnna dispar, sexual difference 

 of colour in, 316. 



Hypopyra, coloration of, 315. 



Ibex, male, falling on his horns, 508 ; 

 beard of the, 531. 



Ibis, white, change of colour of 

 naked skin in, during the breeding 

 season, 389 ; scarlet, young of the, 

 481. 



— — tantalus, age of mature plumage 

 in, 483 ; breeding in immature 

 plumage, 484. 



Ibises, decomposed feathers in, 385 ; 

 white, 492 ; and black, 493. 



Ichneumonidrc, difference of the sexes 

 in, 292. 



Ichthyopterygia, 37. 



fchthyosaurians, 159. 



Idiots,. microcephalous, their charac- 

 ters and habits, 35 ; hairiness and 

 animal nature of their actions, 36 ; 



microcephalous, imitative faculties 

 of, 87. 



Iguana tuberculata, 354. 



Iguanas, 354. 



Illegitimate and legitimate children, 

 proportion of the sexes in, 244. 



Imagination, existence of, in animals, 

 74. 



Imitation, 68 ; of man by menkeys, 

 72 ; tendency to, in monkeys, micro- 

 cephalous idiots and savages, 87 ; 

 influence of, 129. 



Immature plumage of birds, 463, 466. 



Implacentata, 157. 



Implements, employed by monkeys, 

 81; fashioning of, peculiar to 

 man, 82. 



Impregnation, period of, influence of, 

 upon sex, 245. 



Improvement, progressive, man alone 

 supposed to be capable of, 79. 



Incisor teeth, knocked out or filed by 

 some savages, 575. 



Increase, rate of, 44 ; necessity of 

 checks in, 47. 



Indecency, hatred of, a modern virtue, 

 119. 



India, difficulty of distinguishing the 

 native races of, 167 ; Cyprinidae 

 of, 343; colour of the beard in 

 races of men of, 558. 



Indian, North American, honoured 

 for scalping a man of another tribe, 

 117. 



Individuality, in animals, 80. 



Indopicus carlotta, colours of the 

 sexes of, 458. 



Infanticide, prevalence of, 46, 117, 

 256 ; supposed cause of, 577; pre- 

 valence and causes of, 591 et seq. 



Inferiority, supposed physical, 0/ 

 man, 64. 



Inflammation of the bowels, occur- 

 rence of, in Cebus Azara, 7. 



Inheritance, 27 ; of long and short 

 sight, ->33 ; of effects of use of vocal 

 and mental organs, 88 ; of moral 

 tendencies, 123, 126; laws of, 

 227; sexual, 232; sexually limi- 

 ted, 444. 



Inquisition, influence of the, 141. 



Insanity, hereditary, 28. 



Insect, fossil, from the Devonian, 289. 



Insectivora, 534; absence of sec ouiarj 

 sexual characters in, 218. 



