Contributions to the Theory of Natural Selection

Polarity, Forbes’ theory of, 17 (#x1_x_1_i253), 45 (#x2_pgepubid00024).

Polymorphism, 145 (#x4_x_4_i44);

illustration of, 157 (#x4_x_4_i52).

Population of species, law of, 28 (#x2_x_2_i14);

does not permanently increase, 29 (#x2_x_2_i18);

not determined by abundance of offspring, 29 (#x2_x_2_i18);

checks to, 30 (#x2_x_2_i18);

difference in the case of cats and rabbits explained, 32 (#x2_x_2_i20).

Prevision, a case of, 122 (#x4_x_4_i12).

Prioniturus, 196 (#x6_x_6_i10).

Protection, various modes in which animals obtain it, 69 (#x3_x_3_i4)-71 (#x3_x_3_i8), 258 (#x7_x_7_i76);

greater need of, in female insects and birds, 113 (#x4_x_4_i2).

Protective colouring, theory of, 65 (#x2_x_2_i69).

Psittaci (Parrots), sexual colouring and nidification of, 242 (#x7_x_7_i26).

Pterosauria, 298 (#x8_pgepubid00098).

Ptychoderes, 94 (#x3_x_3_i37).

RACES, or subspecies, 160 (#x4_x_4_i57);

of man, origin of, 319 (#x9_x_9_i28).

Redbreast and woodpigeon, protective colouring of, 53 (#x2_x_2_i54), 54 (#x2_x_2_i56).

Representative groups, 9 (#x1_x_1_i242);

of Trogons, butterflies, &c., 12 (#x1_x_1_i247).

Reptiles, protective colouring of, 54 (#x2_x_2_i56).

Rhamphastidæ, sexual colouring and nidification of, 242 (#x7_x_7_i26).

Rhinoceros, 299 (#x8_x_8_i45).

River system, as illustrating self-adaptation, 276 (#x8_x_8_i16).

Roses, Mr. Baker on varieties of, 165 (#x5_x_5_i3).

Rudimentary organs, 23 (#x2_x_2_i3).

SALVIN, Mr. Osbert, on a case of bird mimicry, 107 (#x3_x_3_i58).

Saturnia pavonia-minor, protective colouring of larva of, 63 (#x2_x_2_i67).

Satyridæ, probable means of protection of, 176 (#x5_x_5_i28).

Sauropterygia, 299 (#x8_x_8_i45).

Savages, why they become extinct, 319 (#x9_x_9_i28);

undeveloped intellect of, 339 (#x9_x_9_i58), 341 (#x9_x_9_i60);

intellect of, compared with that of animals, 341 (#x9_x_9_i60), 343 (#x9_x_9_i62);

protect their backs from rain, 346 (#x9_x_9_i68).

Scansorial birds, nests of, 238 (#x7_x_7_i11).

Scaphura, 98 (#x3_x_3_i43).

Scissirostrum, 165 (#x5_x_5_i3).

Scopulipedes, brush-legged bees, 91 (#x3_x_3_i34).

Scudder, Mr., on fossil insects, 301 (#x8_x_8_i47).

Scutelleridæ, mimicked by Longicorns, 96 (#x3_x_3_i39).

Sesia bombiliformis, 90 (#x3_x_3_i34).

Sesiidæ, mimic Hymenoptera, 90 (#x3_x_3_i34).

Sexes, comparative importance of, in different classes of animals, 111 (#x4_x_4_i1);

diverse habits of, 156 (#x4_x_4_i52).

Sexual selection, 156 (#x4_x_4_i52);

its normal action to develop colour in both sexes, 247 (#x7_x_7_i51);

among birds, 283 (#x8_x_8_i24).

Sidgwick, Mr. A., on protective colouring of moths, 62 (#x2_x_2_i66).

Simocyonidæ, 300 (#x8_x_8_i45).