Guiana forest, struggle for life in, 124 Gull community, organization, 106, 134 Gypsy moth, 74 enemies of, 74 Habitats, 5, 60 affected by baseleveling, 86 amphibians, 148 animal, formed by plants, 89, 91 animals classified by, 134 ants, 137, 149 beetles, 145 bird preferences, 148 birds, 137 birds in summer, 146 cave, 112, 143, 144 classification, 59, 138, 139 Collembola, 136 crawfish, 116 dune, 139 fish of Illinois, 140 formed by river floods, 145 fresh-water, 86 grasshoppers, 148 history of their recognition, 138 inland, 91 insects, 128, 135 invertebrate, 146 lake, 87 lake beach, 147 lake fauna, 140 lake, for fish, 147 land, 86 mammals, 145 marine animals, 135, 136, 146 marsh for mollusks, 137 mollusks, 138, 145, 147 mollusks, classification, 138 mollusks of land and fresh water, classification, 138 moor, 139 Oregon sea beach, 149 Orthoptera, 137 oyster, 111, 112, 131, 132 parasitic fauna, 129 pond, 148 preferences of birds, 148 reptiles, 148 sand areas, 146 sand prairie, 139 sandy sea flats, 136, 137 sea bottom, 136 shore animals, 139 spiders, 125, 138 stream, 147, 148 three dimensions, 46 Turbellarian, 127 Habits, Amphipods, 119 _Amphithoe longimana_ Smith, 113 cave-inhabiting bats, 112 Cicindelidæ, 121 fish, 63, 112 formation in crawfish, 106 formation in the turtle, 105 Humble-bee, 118 _Leptinotarsa_, 119 mammals, 118 mammals of North America, 107 mating period of spiders, 115 _Plethodon_, 117 salamanders, 119 solitary wasps of Texas, 113 spiders, 117, 118 squirrels, 115 tortoises, 116 _Venus mercenaria_, 114 Halictus, biocönose, 134 guests and parasites, 134 Hearing in fish, sense of, 116 Heath ants, 149 Hemiptera, seasonal succession, 141 Hemiptera-Heteroptera, catalogue of Nearctic, 71 Hibernation, 115 influence on animal parasites, 130 insects, 128 Holland, sandy flats of, animals, 136, 137 _Homarus Americanus_, behavior of immature stages, 105 Homing pigeons, methods, 113 Honey-bee, natural history, 109 Horde, 132 Human associations, 11 Human behavior, biological and psychological foundations, 133 Humble-bee, domestication, 119 habits, 119 life history, 119 Humidity of air, vegetational control of relative, 90 Humus, effect on animal life of soil, 100 Huttonian theory, 80 _Hydroides Dianthus_ V., behavior modifiable, 106 Hydropsyche, photographing nets of, 64 Hymenoptera of N. America, bibliography, 73 catalogue of species, 73 Hypermetamorphic beetles, 139 Hypotheses, multiple working, 55 Ideas, biometric, 63 life history of scientific, 57