Technique, 15, 57 of fresh-water biology, 62 scientific, 55 Temperature, effect of extremes, 99 in open and wooded areas, 91 influence on digestion of cold-blooded vertebrates, 100 lowering of, and loss of water, 99 physiological effects of high temperature, 99 Termites, Arthropods living with, 130 Terns, noddy and sooty, behavior, 120 Terrapin, diamond-back, cultivation, 110 natural history, 110 Texas, habits of solitary wasps, 113 wasps, solitary, habits, 113 Theory, use, 40 Thermocline, biological significance, 87 Tiger beetles, larval habits, 118 life histories, 118 relation of distribution to plant succession, 90 Tipulidæ, 76 Toad, American, 100 Tomahawk Lake, Wis., Mollusca of, 137 Tortoise, Florida land, 135 habits, 116 perception of space, 121 Tracks and tracking, 58 Trapping, 39, 60 Tree frogs, behavior, 112 color changes, 112 Trees, insects affecting, 74 Trematoda and trematode diseases, index to literature, 129 Trial and error, 104 Tubicolous Annelids, behavior, 112 Turbellarian, behavior, 127 ecology, 127 food, 127 habitat, 127 Turtles, cultivation, 110 discriminative ability of painted, 109 food, 129 formation of habits, 105 natural history, 110 Pennsylvania, 129 _Turtur risorius_, 110 Types of eyes, image-forming powers of various, 110 Typography, 68 Use of theory, 40 Utah, 55 _Vanessa antiopa_ Linn., phototropism, 116 Variation, in animals, 96 in plants, 96 statistical, 60 Vegetation, and animal associations, 90 and control of land animal communities, 133 Caithness, 88 changes in, 88 controlling land animal communities, 90 correlated with lake fauna, 140 development and structure, 88 invading alluvial flats, 89 invading new land surface, 89 Vegetational change, influence upon animals, 85 Vegetational control, of relative evaporating power of the air, 90 of relative humidity of air, 90 Vegetative cycles, causes, 88 _Venus mercenaria_, growth, 108, 114 habits, 114 life history, 108 Veterinary zoölogy, bibliography, 129 Vineyard Sound, invertebrate animals of, 136 Visual discrimination in raccoons, 110 Vital conditions, optimum, 99 Vital optimum, 94 Voices of pigeons as means of social control, 106, 134 Volcanic activity and new land surface, 89 Volcanic islands, new flora, 89 “Walking stick,” behavior, 119 habits, 119 mating instincts, 119 reactions, 119 Walnut Lake, ecological relations of fish, 147 fish ecology, 147 Warning coloration, 62 testing by experiment, 125 Warning colors, insects of South Africa, 128 Wasps, social, 117 behavior, 110 Wasps, solitary, habits, 116, 117 habits, of Texas, 113 instincts, 116, 117