652 



INSECTS. 



INDEX. 



JERDOK. 



Insects, relative size of the cerebral 

 ganglia in, 54; male, appearance 

 of, before the females, 212 ; pursuit 

 of female, by the males, 221 ; period 

 of development of sexual characters 

 in, 236 ; secondary sexual cha- 

 racters of, 274; stridulation, 566. 



Insessores, vocal organs of, 370. 



Instep, depth of, in soldiers and 

 sailors, 32. 



Instinct and intelligence, 67. 



, migratory, vanquishing the 



maternal, 107, 113. 



Instinctive actions, the result of in- 

 heritance, 105. 



impulses, difference of the force 



of, 110, 111 ; and moral impulses, 

 alliance of, 110. 



Instincts, 66 ; complex origin of, 

 through natural selection, 67 ; 

 possible origin of some, 67 ; ac- 

 quired, of domestic animals, 104; 

 variability of the force of, 107 ; 

 difference of force between the 

 social and other, 111, 126 ; utilised 

 for new purposes, 571. 



Instrumental music of birds, 375, 378. 



Intellect, influence of, in natural 

 selection in civilised society, 136. 



Intellectual faculties, their influence 

 on natural selection in man, 127 ; 

 probably perfected through natural 

 selection, 128. 



Intelligence, Mr. H. Spencer on the 

 dawn of, 67. 



Intemperance, no reproach among 

 savages, 119; its destructiveness, 

 137. 



Intoxication in monkeys, 7. 



Iphias glaucippe, 313. 



Iris, sexual difference in the coiour of 

 the, in birds, 383, 425. 



Ischio-pubic muscle, 41. 



Ithaginis cruentus, number of spurs 

 in, 364. 



Tulvs, tarsal suckers of the males of, 

 274. 



Jackals learning from dogs to bark, 



73. 

 Jack-smpe, coloration of the, 491 

 facquinot, on the number of species 



of man, 174. 

 j'aeger, Dr., length of tones increased 



from carrying weights, 32; on the 

 difficulty of approaching herds of 

 wild animals, 100 ; male Silver- 

 pheasant, rejected when his plu- 

 mage was spoilt, 419. 



Jit guars, black, 539. 



Janson, E. W., on the proportions of 

 the sexes in Tomicus villvsus, 253; 

 on stridulant beetles, 302. 



Japan, encouragement of licentious- 

 ness in, 46. 



Japanese, general beardlessness of the, 

 560 ; aversion of the, to whiskers, 

 581. 



Jardine, Sir W., on the Argus phea- 

 sant, 384, 403. 



Jarrold, Dr., on modifications of the 

 skull induced by unnatural position, 

 56. 



Jarves, Mr., on infanticide in the 

 Sandwich Islands, 257. 



Javans, relative height of the sexes 

 of, 559 ; notions of female beauty, 

 580. 



Jaw, influence of the muscles of the, 

 upon the physiognomy of the apes, 

 54. 



Jaws, smaller proportionately to the 

 extremities, 33 ; influence of food 

 upon the size of, 33 ; diminution 

 of, in man, 53 ; in man, reduced 

 by correlation, 562. 



Jay, young of the, 481 ; Canada, 

 young of the, 481. 



Javs, new mates found bv, 407 ; dis- 

 tinguishing persons, 412. 



Jeffreys, J. Gwyn, on the form of the 

 shell in the sexes of the Gastero- 

 poda, 262 ; on the influence of light 

 upon the colours of shells, 263. 



Jelly-fish, bright colours of some, 

 260. 



Jenner, Dr., on the voice of the rook, 

 375 ; on the finding of new mates by 

 magpies, 407; on retardation of the 

 generative functions in birds, 409. 



Jenyns, L., on the desertion of their 

 young by swallows, 108 ; on male 

 birds singing after the proper 

 season, 409. 



Jerdon, Dr., on birds dreaming, 74; 

 on the pugnacity of the male bul- 

 bul, 360 ; on the pugnacity of the 

 male Ortygornis gularis, 363 ; on 

 the spars of Galloperdix^ 364 ; on 



