Forest-tree, section of a Bornean, 32 formed from climbers, 32 Forest-trees, characteristics of, 30 Forest-trees of low growth, 34 Forest-trees, uses of equatorial, 35 Forests, effect of on rainfall and drought, 19 devastation caused by destruction of, 20 equatorial, 29 undergrowth of tropical, 34 _Formica gigas_, 81 Foxes, none in Isle of Wight in 1605, 305 Frogs and toads, 116 Frog, with bright colours uneatable, 175 Frogs of oceanic islands, 309 Fruit-bats, 119 Fruits of equatorial forest-trees, 36 Fruits, attractive colours of, 224 protective colours of, 225 greater antiquity of protected than attractive, 227 G. Galapagos, colours of productions of, 163 poor in flowers and insects, 235 weedy vegetation of, 272 Gardner, Dr., on a large water-boa, 115 Geckos, 112 Geiger, on ancient perception of colour, 245 _Geranium pratense_, _G. pusillum_, 233 Gibbons, 116 Ginger-worts, 47 Gladstone, Mr., on the colour-sense, 245 Glow-worm, use of its light, 205 Goliath cuckoo, 105 Gosse, Mr., on Jamaica humming-birds, 132, 135 on the pugnacity of humming-birds, 134 on food of humming-birds, 137 Gould, Mr., on the motions of humming-birds, 131 Grammatophyllums, 51 Green, why the most agreeable colour, 244 Grisebach, on cause of vivid colours of arctic flowers, 237 _Guilielma speciosa_, 42 Gums from equatorial forest-trees, 36 H. _Habenaria chlorantha_, 230 Habits of humming-birds, 130 Heat due to condensation of atmospheric vapour, 14 changes colours, 183 Heliconiinæ and Acræinæ, local resemblances of, 256 Hindostan and Africa, resemblances of fauna of, 328 Hooker, Sir J. on flowers of Auckland Isles, 238 on deficient odour of New Zealand flowers, 277 Hornbills, 107 Horns of beetles, probable use of, 202 Howling-monkeys, 118 Humming-birds, number of, 124, 133 distinctness of, 125, 129 structure of, 125 colours and ornaments of, 127 descriptive names of, 129 motions and habits of, 130 display of ornaments by males, 134 food of, 135 nests of, 137 geographical distribution and variation of, 138 of Juan Fernandez, 140 influenced by varied conditions in South America, 147 relations and affinities of, 148 sternum of, 151 eggs of, 152 feather-tracts of, 152 resemblance of swifts to, 152 nestlings of, 153 differences from sun-birds, 154 I. Iguanas, 113 Indian peninsula once an island, 325 ancient fauna of, 325 Insects, wingless, 97 general observations on tropical, 98 Insular plants and insects, relations of, 267 Interference-colours in animals, 184 Islands, influence of locality on colour in, 257 J. Jacamars, 105 Juan Fernandez, humming-birds of, 140 insects of, 270 abundance of humming-birds in, 273 L.