STAINTON, Mr., on moths rejected by turkeys, 78, 88. STALACHTIS, a genus of Erycinidae, the object of mimicry, 84. STINGING insects generally conspicuously coloured, 72. STREPTOCITTA, 196. STURNIDAE, sexual colouring and nidification of, 244. STURNOPASTOR, 239. ST. HELENA, 10. _Streptolabis hispoides_, 93. STRUGGLE for existence, 28, 33. SURVIVAL of the fittest, law of, stated, 33; its action in determining colour, 67. SWAINSON'S circular and quinarian theory, 45. SYLVIADAE, sexual colouring and nidification of, 245. SYNAPTA, 258. _TACHORNIS phoenicobea_, 228. _Tachyris hombronii_, 172; _ithome_, 172; _lycaste_, 172; _lyncida_, 172; _nephele_, 172; _nero_, 172; _zarinda_, 172. TANAGRIDAE, sexual colouring and nidification of, 245. TAPIR, 299. TELEPHORI, similar colouring of two sexes, 114. TEMPERATE and cold climates favourable to civilization, 318. THECODONTIA, 299. THERATES, mimicked by Heteromera, 95. _Thyca descombesi_, 172; _hyparete_, 172; _rosenbergii_, 172; _zebuda_, 172. TIGER, adaptive colouring of, 52. TIMES newspaper on Natural Selection, 296. TOOLS, importance of, to man, 314. TREE FROGS, probable mimicry by, 103. TRICONDYLA, 97. TRIMEN, Mr., on rank of the Papilionidae, 136. TRISTRAM, Rev. H., on colours of desert animals, 50. _Trochilium tipuliforme_, 90. TROGONIDAE, sexual colouring and nidification of, 241. TROPICAL birds often green, 52. TROPICS, most favourable to production of perfect adaptation among animals, 68; not favourable to growth of civilization, 318. TROPIDORHYNCHUS mimicked by orioles, 104. TRUTHFULNESS of some savages, 353; not to be explained on utilitarian hypothesis, 354. TURDIDAE, sexual colouring and nidification of, 245. TURNIX, 115, 251. TYNDALL, Professor, on origin of consciousness, 361. UPUPIDAE, sexual colouring and nidification of, 241. USEFUL and useless variations, 34. UTILITY, importance of the principle of, 47, 127. VARIABILITY, simple, 144. VARIATIONS, useful and useless, 34; laws of, 143, 266; as influenced by locality, 166; of size, 168; universality of, 287-291; are there limits to, 291; of domestic dogs, 293; of pigeons, 293. VARIETIES, instability of, supposed to prove the permanent distinctness of species, 26; if superior will extirpate original species, 36; its reversion then impossible, 37; of domesticated animals may partially revert, 38, 40; inconvenience of using the term, 161. VERTEBRATA, mimicry among, 99. VOICE of man, not explained by natural selection, 350. VOLUCELLA, species of mimic bees, 75, 98. WALSH, Mr., on dimorphism, of _Papilio turnus_, 153. WEAPONS and tools, how they affect man's progress, 314. WEEVILS often resemble small lumps of earth, 58.