Illinois, ecological relations of entomophilous flora and anthophilous insect fauna, 142 fish, 140 sand areas, biology, 146 sand prairies, associational study, 139 State Entomologist’s reports, 74 Illinois River, entomology, 74 plankton, 147 Image-forming powers of eyes of various types, 110 Imitation, and intelligence in birds, 117 criterion, 117 Index, Agricultural reports of the U. S. patent office, 72 circulars, U. S. Entomology Bureau, 73 Experiment Station Record, 76 Illinois State entomologist’s reports,74 Insect Life, 72 Lintner’s New York State entomologist’s reports, 74 Missouri reports on insects, 77 Ontario entomological society reports, 72 Orthoptera of North America, 77 papers on biological survey of U. S., 128 Riley’s Missouri entomological reports, 77 Index catalogue of medical and veterinary zoölogy, 129 Indian corn, _see_ Corn Indiana, caves and their fauna, 144 insect galls, 143 Individual development, 97 Individual ecology, 3, 8, 23, 24 and the associational unit, 131 Influence, of sessile habit, 100 of slowest factors, 98 Inland habitats, 91 Insect associations, changes in, 127 Insect depredations in forests, 127 Insect enemies of cotton boll weevil, 125 Insect fauna of the giant cactus of Arizona, 135 Insect galls, Europe, 143 Indiana, 143 New York, 143 Insect guests of Florida land tortoise,135 Insect Life, 111 index, 72 Insect oscillations regulated by birds, 123 Insectivorous Coleoptera, 127