OBEDIENCE. 



INDEX. 



ORYCTES. 



451 



0. 



Obedience, value of, i. 162. 



Observation, powers of, possessed by- 

 birds, ii. 109. 



Occupations, sometimes a cause of 

 diminished stature, i. 115; effect 

 of, upon the proportions of the body, 

 i. 116. 



Ocelli, absence of, in female Mutil- 

 lidee, i. 341. 



Ocelli of birds, formation and vari- 

 ability of the, ii. 132. 



Ocelot, sexual ditferences in the 

 colouring of the, ii. 287. 



Ocyphaps lophotes, ii, 96. 



Odonata, i. 314. 



Odonestis potatoria, sexual difference 

 of colour in, i. 398. 



Odour, correlation of, with colour of 

 skin, i. 248 ; emitted by snakes in 

 the breeding-season, ii. 30 ; of 

 mammals, ii. 278. 



Oecanthus nivalis, difference of colour 

 in the sexes of, i. 361. 



Oidemia, ii. 226, 227. 



Olivier, on sounds produced by 

 Pitnelia striata, i. 385. 



Om'doplia hrunnea, stridulation of, i. 

 381. 



Onitis furcifer, processes of anterior 

 femora of the male, and on the 

 head and thorax of the female, i. 

 372. 



Ontkophagus, i. 370. 



Onthophagus rangifer, sexual differ- 

 ences of, i. 369 ; variation in the 

 horns of the male, i. 370. 



Ophidia, sexual differences of, ii. 29. 



Opossum, wide range of, in America, 

 i. 219. 



Optic nerve, atrophy of the, caused 

 by destruction of the eye, i. 116. 



Orang-Outan, ii. 323 ; Bischoff on 

 the agreement of the brain of the, 

 with that of man, i. 11 ; adult age 

 of the, i. 13 ; ears of the, i. 21 ; ver- 

 miform appendage of, i. 27 ; plat- 

 forms built by the, i. 36 ; alarmed 

 at the sight of a turtle, i. 43 ; 

 using a stick as a lever, i. 51 ; 

 using missiles, i. 52 ; using tlie 

 leaves of the Fand inus as a night 

 covering, i. 53 ; hands of the, i. 



139 ; absence of mastoid processes 

 in the, i. 143 ; direction of the 

 hair on the arms of the, i. 192 ; its 

 aberrant characters, i. 197 ; sup- 

 posed evolution of the, i. 230 ; 

 voice of the, ii. 276 ; monogamous 

 habits of the, ii. 361 ; male, beard 

 of the, ii. 284. 



Oranges, treatment of, by monkeys, 

 i. 139. 



Orange-tip butterfly, i. 388, 393, 

 394. 



Orchestia Darwiiiii, dimorphism of 

 males of, i. 332. 



Orchestia Tucuratinga, limbs of, i. 

 330, 331, 337. 



Ordeal, i. 68. 



Oreas canna, colours of, ii. 288. 



Oreas Derbianus, colours of, ii. 288, 

 299. 



Organs, prehensile, i. 256 ; utilised 

 for new purposes, ii. 335. 



Organic scale, von Baer's definition 

 of progress in, i. 211. 



Orioles, nidification of, ii. 167. 



Oriolus, species of, breeding in im- 

 mature plumage, ii. 214, 215. 



Oriolus melanocephalus, coloration of 

 the sexes in, ii. 178. 



Ornaments, prevalence of similar, i. 

 233 ; fondness of savages for, ii. 

 338 ; of male birds, ii. 50. 



Ornamental characters, equal trans- 

 mission of, to both sexes, in mam- 

 mals, ii. 297 ; of monkeys, ii. 306. 



Omithoptera croesus, i. 310. 



Ornitkorhynchus, i. 200 ; spur of the 

 male, ii. 242 ; reptilian tendency 

 of, i. 204. 



Orocetes erythrogastra, young of, ii. 

 219. 



Orrony, Grotto of, i. 28. 



Orsoiacna atra, difference of colour 

 in the sexes of, i. 368. 



Orthoptera, i. 352 ; metamorphosis 

 of, i. 292 ; stridulating, auditory 

 apparatus of, i. 353 ; colours of, i. 

 360; rudimentary stridulating or- 

 gans in female, i. 359 ; stridula- 

 tion of the, and Homoptera, dis- 

 cussed, i. 360. 



Ortygornis gularis, pugnacity of the 

 male, ii. 44. 



Oryctes, stridulation of, i. 381 ; sexual 



2 G 2 



