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 beat 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 
Trochilidse, 313 
Trochilium tipuliforme, 64 
Trogonidse, 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 
Tropidorliynchus mimicked by orioles, 
73 
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 
Upupidjs, 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, 159 
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 
species, 28 
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 
Volueella, 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. Mausel, on plants of 
Karoo, 397 
