ANALYTICAL INDEX 



469 



Sterility, of hybrids, bearing of 

 Darwin's work on heterostyled plants 

 upon, xxviii, 90, 91 ; between species, 

 49; difference between Darwin's 

 and Wallace's views on, 49, 8o, 89 ; 

 between Darwin's and Huxley's 

 views on, 49, 77-80, 82, 201 ; 

 of hybrids, 63, 64, 77, 78; be- 

 tween species characteristic, but be- 

 tween domestic races very rare, 77- 

 80; between certain artificially selec- 

 ted races, 78-80; reduced by domes- 

 tication, 79; attempt to induce by 

 selection, 79, 80; not due to Natural 

 Selection, 80, 89 ; causes of, 80-2 ; 

 germinal causes of, 80-2 ; various 

 causes of, 81 n. 1 ; possible between 

 tnds of ' syngamic chain ', 89 ; inci- 

 dental rather than selected, 91 ; cross- 

 fertilization and, 90, 91 : see also 

 xxviii ; not a test of specific dis- 

 tinctness, 91. 



Sticks, protective (procryptic) 

 resemblance to, 370. 



Stictoploea harrisi, 372, 376. 



Stillness essential in protective 

 resemblance, 298. 



Stimulus and Mechanism as 

 Factors in Organization, J. B. 

 Farmer, 74 n. 2. 



Stimulus to inquiry, interest as 

 a, xliv-xlvi. 



Stimulus of light in adjustable 

 protective resemblance, 305 ; experi- 

 mental investigation into seasonal 

 changes and physiological, 311, 312, 

 340-2. 



Sting, associated with warning 

 colours, 315, 316 ; no defence if food 

 scanty, 317 ; hardness as a defence, 

 compared with smell, &c, and, 370. 



Stinging insects, Batesian mimics 

 of, 376 ; Miillerian mimics of, 376 : 

 see also 230-1 ; see also bees, Fos- 

 sores and wasps. 



Stockholm Natural History 

 Museum, type f. of L. chrysippus 

 from Cameroons in, 321 n. I. 



Stone, protective (procryptic) 

 resemblance to, 298, 301. 



Stonechat, South African, 

 Lycaenid chased by, 284. 



Stratified rocks, thickness of, 16 ; 

 lapse of time during deposition of, 

 1 6, 17 ; uniformity of conditions 

 during deposition of, 17-19. 



Stray Feathers, 290. 



Acronycta, fertile with 

 not with bred males, 



strigosa, 

 wild but 

 87 n. 1. 



Striking Examples of Mul- 

 lerian Mimicry, X. 331-6; (a) 

 the New World, 331-3 ; (6) the 

 Old World, 333-6. 



Stripes of zebra, invisibility pro- 

 duced by, 298. 



Struggle for Life, hours 

 when most Severe, X. 303. 



Struggle for life : see also Natural 

 Selection ; a factor of selection, 96 ; 

 utility in the, 105-9 ! Palae- 

 ontology and, 107-8 ; conditions of, 

 in insects, 117, 155-7; especially 

 severe in winter, 148 ; in the dry 

 season, 148, 208-11; during pupal 

 period, 157-60; in young birds, 

 167, 167 n. 2, 168; insufficiently 

 appreciated by J. C. Prichard, 191 ; 

 in S. America, 248 j curious evidence 

 of, 291, 292 ; imperfect knowledge 

 of details of, 302, 303 ; complexity 

 of, 323 ; effect upon insect life of 

 enemies', 328. 



Strutt, Hon. R. J., on radium in 

 rock, 15 n. 2. 



Study of Adaptation Stimu- 

 lates AND DOES NOT BAR 

 Inquiry, Introd. xliv-xlvii : see also 

 74 n. 2. 



Study of Insects and Ques- 

 tion 'Are Acquired Char- 

 acters Hereditary?' Essay V, 

 139-72. 



Sty/ops, effect of, upon bees, 380. 



subbuteo, Falco, Terias found in 

 stomach of, 284. 



Suberites domuncula, 357. 



Subjective Judgement of 

 Discontinuity, Introd. xvii. 



Sub-species or Geographical 

 Races traverse Diagnosis, II. 

 75-76. 



Sub-species, importance for the 

 study of evolution, of geographical, 

 xvi ; united by syngamy, 75, 76. 



Sucking, an instinctive action, 117. 



Sudan, ant-like Locustid from, 

 256, 257, 258 (Fig. 5), 280. 



suffocans, Mephitis, warninj 

 colours of, 315. 



sulcirostris, Cleonus, colour ad- 

 justment probable in, 307. 



Summa Theol., St. T. Aquinas, 

 55- 



