INDEX 



291 



Flocks of birds, breeding, 111; 

 social organization, 175, 

 206; leadership in, 196; 

 wheeling flight, 198; of 

 mixed species, 197, 248 



Folks, Homer, 230 



Forced movements, 43. (See 

 Tropism) 



France, population trend, 223 



Fresh water, mass protection 

 from, 63 



Fundulus, learning, 164 



Gates, Mary, 149 



Gene frequency, 118 



Germany, population trend, 

 220, 223, 225, 226; children 

 in wartime, 230 



Goldfish, mass protection, 53, 

 56, 68; effect of numbers on 

 growth rate, 92; on amount 

 of food taken, 136; on 

 learning, 159; leadership, 

 166; imitation, 170 



Gross, A. O., 113 



Group behavior, 22, 133; 

 stimulation of feeding, 136; 

 organization, 175 



Growth, retarded by over- 

 crowding, 91; of goldfish, 

 effect of numbers, 92; ef- 

 fect of extracts on, 72, 96; 

 of mice, effect of numbers, 



99 

 Gulls, minimal population, 

 110; effect of numbers on 

 survival, 111 



Hawaii, snails, 123 

 Heath hen, 113, 122 



Henry IV of France, 236 

 Hibernation, 32, 58 

 Holmes, S. J., 231 

 Hormones, effect on social 

 rank, 193; social, 264, 267 

 Hoskins, Walter, 92 

 Hunt, Harrison, 228 



Imitation, 170 



Insects, social, 26, 29, 32, 259; 



population in nature, 39; 



evolution of, 88; as enemies 



of man, 241; castes, 250 

 Instinct, 249; definition, 246; 



social, 244, 245, 249 

 International relations, 210 

 Isopods, behavior, 20 

 Italy, population trend, 219, 



225, 226, 227; children in 



wartime, 230 



Japan, population, 226 

 Johnson, W. H., 77 

 Jordan, David Starr, 228 



Kellogg, John, 185 

 Kessler, K. F., 26 

 Kropotkin, Prince, 27 



Leader, of a group, 166, 175, 

 196, 207; relation to peck- 

 order, 199 



League of Nations, 236 



Learning, effect of numbers, 

 142 



Liven good, Wayne, 92 



Lobster-krills, 34 



Locusts, migratory, 35; phases, 

 272 



