INDEX 



491 



Temperate and cold climates favour- 

 able to civilisation, 177 

 Temperature of London and Batavia 

 compared, 221 



of different latitudes, various 



causes of, 221 



influenced by heat of soil, 222 

 influenced by aqueous vapour of 



atmosphere, 223 

 of tropical and temperate zones, 



cause of illustrated, 226 

 Tertiary gravels of Colorado, stone 



implements in, 448 

 Thaumastura cora, very pugnacious, 



381 



Thecodontia, 164 

 Therates, mimicked by Heteromera, 



67 



Tiger, adaptive colouring of, 39 

 Times newspaper on natural selection, 



162 

 Timor and Flores, white-marked birds 



of, 388 



Timor and Scotland, climates com- 

 pared, 227 



Tools, importance of, to man, 174 

 Toucans, 298 

 Tree-frogs, probable mimicry by, 73 



abundance of, in the tropics, 305 

 Tricondyla, mimicked by cricket, 69 

 Tristram, Rev. H., on colours of 



desert animals, 37 

 Trochilida;, 313 

 Trochilium tipuliforme, 64 

 Trogonidae, sexual colouring and nidi- 



fication of, 125 

 Trogons, 297 



Tropical birds often green, 38 

 Tropical vegetation, concluding re- 

 marks on, 267 



probable causes of its luxuriance 



and variety, 268 

 Mr. Belt on, 268 

 birds, coloration of, 300 

 green, 300 

 dull-coloured, 301 



Tropics, most favourable to production 

 of perfect adaptation among ani- 

 mals, 49 

 not favourable to growth of 



civilisation, 177 

 limitation of, 218 

 aspects of animal life in, 309 



Tropidorhynchus mimicked by orioles, 



Trunks, variety of, 241-243 



probable cause of flowering, 244 

 Truthfulness of some savages, 200 

 not to be explained on utilitarian 



hypothesis, 201 

 Turdidse, sexual colouring and nidifi- 



cation of, 128 

 Turnix, 81, 132 

 Twilight, short at equator, 232 

 Tyndall, Professor, on origin of con- 

 sciousness, 206 

 Typical colours, 374 



UPUPID.E, sexual colouring and nidifi- 



cation of, 125 



Useful and useless variations, 27 

 Utility, importance of the principle of, 



35, 89 



VAMPIRE-BATS, 308 



Vanda lowii, 257 



Variation, how influenced, 326 



studied by Darwin, 457, 460, 462 

 Variations, useful and useless, 27 



laws of, 142 



universality of, 156, 150 



are there limits to, 159 



of domestic dogs, 160 



of pigeons, 160 



Varieties, instability of, supposed to 

 prove the permanent distinctness of 

 species, 21 



if superior will extirpate original 



its reversion then impossible, 29 

 of domesticated animals may 



partially revert, 29, 30 

 Vegetation, equatorial, 238 

 Vertebrata, mimicry among, 70 

 Vipers, green, 304 



Vitality a cause of bright colour, 365 

 Voice of man, not explained by 



natural selection, 198 

 Volucella, species of mimic bees, 54, 

 70 



WARNING COLOURS, theory of, 361 

 Wasps and bees, 286 

 Wave-lengths of coloured rays, 355 

 Weale, Mr. J. P. Mansel, on plants of 

 Karoo, 397 



