HoHsm, 432, 684, 693, 721- 

 729. See also Units, bio- 

 logical. 

 Homeostasis, 6, 184, 426, 

 631, 671, 694, 695, 728, 

 729. See also Food stor- 

 age; Temperature, body. 

 ecological, 672, 695, 710, 



728, 729 

 in mammals, 672 

 social, 215, 399, 424, 425, 

 428, 672, 694, 695, 701, 

 728 

 Homing, 412, 604, 645 



birds, magnetism and, 157 

 Homoiosmotic animals, 168 

 Homoiothermy, 97, 98, 214, 



215, 626 

 Homology, 427, 435, 633, 

 635, 636, 666, 672, 674, 

 676, 681, 693 

 Homoptera, 248, 424, 706. 



See also various families. 

 Hooker, 37, 38 

 Hopkins, biocHmatic rule, 18, 



117, 118 

 Hopkins' host-selection prin- 

 ciple, 494, 518, 615 

 Hoplodermatidae, 465 

 Horizons, soil, 217, 218, 219, 



225 

 Hormones, 428, 671, 679, 



689, 722 

 Horseflies, 629 

 Horses, 589, 637, 638, 655, 



679, 707 

 Horseshoe crabs, 158, 632, 



680 

 Host, 684, 708, 709, 719 

 density, 700. See also 



Population density. 

 isolation, 613, 708. See 



also Isolation, habitat. 

 selection, 258, 615, 700. 

 See also Habitat selection. 

 specificity, 22, 239, 258, 

 373, 486, 612-616, 698, 

 699, 700, 707, 713, 715, 

 717, 720 

 Host-parasite adaptation, 708, 

 709, 720 

 interactions, 379 

 relations, 60, 254,255,271, 

 327, 384, 385, 613-616, 

 628, 643, 644, 670, 671, 

 675, 679, 686, 699, 700- 

 704, 705, 707-710, 723, 

 728 

 Host-plants, 614, 698, 699, 

 703, 711, 724. See also 

 Gall insects. Herbivores, 

 Host specificity, Phyto- 

 phages. Plant feeders. 



SUBJECT INDEX 



Host-selection principle, Hop- 

 kins', 494, 518, 615 

 Hot springs, 103 

 Hovarth, 21 

 Humboldt, Alexander von, 33 



rule, 461 

 Humidity, 20, 51, 181, 182, 

 184, 185-189, 207, 208, 

 209, 210, 656, 666, 672 



behavior and, 188 



color and, 187, 626 



control, 425, 428, 429, 672. 

 See also Homeostasis. 

 modes of, 185, 186 



diel cycle, 182 



gradient, 182, 428 



insect relations, 187, 188, 

 189 



near ground, 212 



populations and, 335, 336, 

 722 



relative, in forests, 480 

 Humus, 224, 697 

 Hurricane(s), 146, 147 



community effects, 146 



transport, 149 

 Hutchinson, G. E., 343 

 Huxley, Juhan S., 57 

 Huxley, T. H., 23, 31, 38 

 Hybrid(s), incapacity, 606, 



623, 677 



inviabihty, 606, 622, 623, 



624, 626, 676 



origin of species, 624, 644, 



647 

 selection, 623, 624, 625 

 selective ehmination, 606, 



616, 622, 623 

 sterihty, 606, 618, 623, 626 

 survival, 617 

 Hydrarch succession, 572 

 Hydrobiology, history, 36, 44, 



46, 51 

 Hydrocarbons, origin, 75 

 Hydroceles, 184, 185 

 Hydrogen ion concentration, 

 172, 221, 340, 547 

 acid normahty and, 



172 

 adsorption relations, 



176 

 alkahne normality and, 



172 

 animal life and, 173 

 population and, 340 

 reaction of fishes to, 



174, 175 

 redox potential and, 



195 

 soil, 221, 222, 223, 



224 

 water, 173 



hardness, and, 204 



817 



Hydrogen sulfide, dissolved, 



193, 194, 196 

 Hydrological cycle, 177, J 78 

 Hydrolysis, soil, 219 

 Hydrophytes, 184 

 Hydrosere, 572, 577 

 Hydrosphere-hthosphere, in- 

 terphase, 158, 159-163 

 Hydrostatic pressure, 136 

 Hydrothermal index, 207 

 Hygrocoles, 184, 185 

 Hymenoptera. See also var- 

 ious famihes, and Bees, 

 Ants, Wasps. 

 exploitation of, 715 

 gall-making, 491 

 genetics of, 647, 688 

 hibernating, 538 

 parasitic, 335, 383, 472, 

 615, 653, 675, 676, 700 

 pupation rhythm, 552 

 societies, 419-435, 686, 691 

 stratification of, 494 

 in tree holes, 570 

 Hyperbola, temperature, 109. 

 Ill 

 time-temperature, 108 

 Hypohmnion, 94, 96, 499, 

 505, 573 

 dissolved gases, 192, 193. 

 194, 196 

 salts, 196, 202, 203, 204 

 redox potential, 196 

 Hypothesis, Rubner's, 113 



Ice, 91, 178, 179, 644, 645 

 Ichneumonidae, 715 

 lUinois, forest floor popula- 

 tion, 488 

 pyramid of numbers, 522 

 pastures, succession in 



dung, 567, 568, 569 

 seasonal succession in, 102, 



532, 533 

 succession in Fox Lake 

 area, 572 

 Illuviation, 218 

 Imbalance. See Unbalance. 

 Immigration, 649, 658, 681, 

 683. See also Dispersion, 

 Emigration, Migration. 

 coefiicient, 649 

 pressure, 649 

 Immunity, 642, 643,644,707, 



708, 709 

 Immunology, 601, 711 

 Imprinting, 7 



Inbreeding, effect of, 602- 

 605, 615, 649, 654, 656, 

 657, 662, 681, 683, 687, 

 692 

 Incubation of chrysalids of 

 Tenebrio molitor, 109 



