ANALYTICAL INDEX 



465 



COLOURS ; APOSEMATIC AND EPI- 

 SEMATIC CHARACTERS, X. 315-58. 

 For divisions, sections, sub-sections, 

 &c., see pp. 294-6. 



Sematic Colours (see Warning 

 Colours and Signalling Colours) : 

 place in scheme of the bionomic uses 

 of colour, 226; defined, 315. 



Semper, Karl, on Natural Selec- 

 tion not creative, xxii ; letter from 

 Darwin to, 74. 



Senses, Instincts, and Intelli- 

 gence of Animals, &c., Sir John 

 Lubbock, 161. 



septentrionalis, Croesus, habits of 

 larvae of, 238, 239 ; transition from 

 cryptic to aposematic defence in 

 gregarious larvae of, 319, 320. 



serena, Acraea, model of wet f. of 

 B.gotzius, 341. 



Serpents, 312, 319, 324, 326, 367, 

 367 n. 2, 368, 376. For analysis see 

 snakes. 



sesamus, Precis, seasonal forms of, 

 208 ; dry form (sesamus) bred (1898) 

 from wet (natalensis), 208, 339, 340, 

 340 n. 4 ; attempt to determine the 

 physiological cause of change, 340 ; 

 procryptic under surface of, while 

 natalensis is a rough mimic of 

 Acraea, 339, 339 n. 1, 340 ; S. African 

 habitat of, 340. 



Sesia (Trochiliuni) , transparency 

 of scales in, 25 1, 366 : see also Troch- 

 ilium, 251, 365, 366. 



Sesiidae, mimicry of Aculeata by, 

 251, 365, 366. 



severina, Belenois, experiments on 

 seasonal forms of, 311-12. 



SEVERITY OF STRUGGLE GREAT- 

 EST AT CERTAIN HOURS, X. 303. 



Seward, A. C., on the earliest land- 

 plants, 44 ; F. Darwin and, on 

 Prichard as an evolutionist, 174 n. 2, 

 175 n. i. 



Sex, predetermined in ovum, 133. 



SEXES ALIKE OF BOTH MODEL 

 AND MIMIC, X. 371. 



SEXES DIFFERENT, MALE 

 MIMICKING MALE, FEMALE 

 FEMALE, X. 371. 



Sexes of insects, and Natural 

 Selection, 246, 247 ; mimicry and 

 the, 215-18, 244-7, 279, 347, 353, 

 372-5 ; recognition between per- 

 haps aided by smell in close 

 mimicry, 358. 



Jl 



Sexual reproduction, Weismann's 

 interpretation of, 127, 128, 137. 



SEXUAL SELECTION, EPIGAMIC 

 COLOURS, X. 379, 380. 



Sexual Selection : see also Epi- 

 gamic ; a cause of asyngamy, 65, 85-8 ; 

 suggested as cause of mimicry, 225, 

 228, 272 ; objection to as explanation 

 of protective resemblance, 227, 228 ; 

 objections to as explanation of 

 mimicry, 227, 228, 233, 236, 245, 

 246, 260, 261, 267, 270, 273, 

 275, 276, 278-82 ; objections to less 

 strong than to other alternatives to 

 Natural Selection, 236 ; T. Belt on 

 white patch of male Dismorphina, 

 240 ; first suggested by Darwin 

 (1858), 379; difficulty of theory of, 

 379 ; selection proved by diversity of 

 elements co-operating to produce 

 effect, 379; supported by observa- 

 tions on courtship of spiders, 380 ; 

 and of grasshoppers, 380. 



SHADOW, NEUTRALIZATION OF, 

 X. 299-300: see also 298, 313. 



SHADOW, ADJUSTABLE NEUTRAL- 

 IZATION OF, X. 300. 



SHADOW, REDUCTION OF, BY 

 ATTITUDE, X. 300, 301 : see also 

 289. 



Shadow, importance in desert of, 

 298 ; parallelism of main pattern lines 

 of moth with main lines of, 156, 301 ; 

 cast by dead leaves, resemblance to, 

 299 ; elimination of, in aggressive 

 resemblance, 313. 



' Sham death ', meanings of, 323, 

 324; appearance of real death 

 different from that of, 324 ; procryptic 

 in spiders, beetles, caterpillars, 323 : 

 see also 155 ; aposematic in un- 

 palatable moths, 323, 324. 



Shape, relation to general and 

 special protective resemblance of, 

 297, 298 : see also xxiv n. 2. 



Sharks, teeth of, on ocean floor, 20 ; 

 in early Palaeozoic, 30. 



Sharp, David, on ant-like bug 

 larva, 257 n. I. 



Sheep, Jacob's experiments on, 

 1 86 ; J. C. Prichard on changes of 

 fleece of, in tropics, 190. 



Shelford, R., results obtained by 

 quoted in Essay X, 293 ; on mimicry 

 of Hymenoptera by Bornean Longi- 

 corns, 257 n. I, 280; on Bornean 

 Clytinae as models for other Longi- 



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