424 



INDEX 



Tibicen, see Cicadas 

 Ticks, adaptive differences, 286 

 Tiger, paler coloured in north, 241 

 Tiger-beetles, see Cicindela 

 Tillyard, colour-polymorphism, 282 

 ' Time-character ' concept, 65 

 Timofeef-Ressovsky, heterozygous wild 



Drosophila, 26 

 Tiphia, physiological races, 1 20 

 Tipula, isolation of species, 143 

 Tisiphone, geographical variation, 113 

 — , specific intergradation, 89 

 Titanotheres, size of horns, 331 

 Tonnoir, adaptation of Blepharo- 



ceridae to water-flow, 266 

 Topographical groups, 1 1 

 Tornier and Milewski, experiments on 



Goldfish, 41 

 Torrents, adaptation to life in, 265 

 Tower, experiments on Leptinotarsa, 37 

 Toxoptera, temperature-relation with 



Lysiphlebus, 359 

 Toyama, voltinism in silkworms, 23, 



Trachusa, variation in nesting habits, 



120 

 Trachyponus, variation in habits, 54 

 Tragulus, races of, 116 

 Transients, 65 



Trends, adaptive explanation of, 55 

 — , environmental, 44, 77 

 — , in colour of Tiger, 241 

 — , non-environmental, 78 

 ■ — , relation to mimicry theory, 258-59 

 Trialeurod.es, optimum conditions, 358 

 Troglodytes, geographical races, 106 

 — , specific intergradation, 89 

 Trogoderma, experiments on, 79 

 Trout, xanthochroism, 93 

 Trueman, correlation in Carbonicola, 



163 

 — , on lineages, 65 

 - — , selection of colour-forms of Cepea, 



201 

 Tschulock, logical fallacy in ' Origin 



of Species,' 184 

 Tubifex, experiments on, 36 

 Turesson, ecotype and ecospecies, 72 

 Tutt, seasonal occurrence of Agriades, 



r 43 

 Typhlops, characters of, 286 

 Typhlosaurus, characters of, 826 



Uca, male chela?, 332, 337 



Units, structural, 60 



Use and disuse, 42, 324 



Uvarov, climatic factors in death-rates 



in insects, 194 

 — , differential effect of temperature 



on hosts and parasites, 359 



Uvarov, fluctuations in insects, 19 



— , race-formation in Cyrtacanthacris, 



108 

 — , voltinism in insects, 144 



Vandel, local parthenogenesis in 



Hymenoptera, 123-24 

 Vanessa, selective elimination of pupas, 



203 

 Varanus, adaptive difference, 290 

 Variants, distribution in space, 6 

 — , individual, 8 

 Variation, classification of, 18 

 — , continuous and discontinuous, 86 

 — , definition, 1 



— , effect of range of species, 90 

 — , geographical, see Geographical races 

 — , heritable, difficulty of recognising, 



1.9. 78 

 — , heritable, distribution among the 



phyla, 81 

 — , in different parts of animals, 5 

 — , inherent capacity for, 1 12, 126, 140 

 — , independent, of characters, 166 

 — , limits of, 7, 192 

 — , limits of, Darwin's view, 183 

 — , mode of occurrence, 8, 9 

 — , nature of, as affecting Natural 



Selection, 216-30 

 — , non-living substances, 3 

 — , origin of, 3 



— , problems raised by study of, 13-14 

 — , reduced or not reduced by selection, 



206-12 

 Variety, 63, 67 

 Vavilov, Law of Homologous Series, 



326 

 Vermes, tubes as a protection against 



the environment, 360 

 Vermetus, shell of, 336 

 Vernon, criticism of Weldon on Car- 



cinus, 197-98 

 Vervollkommnungsprinzip, 324 

 Vespa, correlation of characters, 1 73 

 — , selective elimination of hibernating 



queens, 207-8 

 — , variation in habits, 54 

 Vespa crabro, geographical races, 1 1 6 

 Vestiaria, young taught what to eat, 254 

 Virulence in Protozoa, 119 

 Vivipara, intermediacy, 88 

 Vogt, colour-convergence in Bombus, 



2 5. 8 . 



Voltinism in insects, 53, 144, 357 



Volucella, mimicry of bees, 252, 257 



Waagen, Collectivart, 71 

 — , Formenreihe, 58 

 Wagner, isolation, 128 



