I. IMITATION 179 II. INTERCOMMUNICATION 193 III. SOCIAL COMMUNITIES OF BEES AND ANTS 205 IV. ANIMAL TRADITION 220 V. THE EVOLUTION OF SOCIAL BEHAVIOUR 225 CHAPTER VI _THE FEELINGS AND EMOTIONS_ I. IMPULSE, INTEREST, AND EMOTION 235 II. PLAY 248 III. COURTSHIP 258 IV. ANIMAL “ÆSTHETICS” AND “ETHICS” 270 V. THE EVOLUTION OF FEELING AND EMOTION 282 CHAPTER VII _THE EVOLUTION OF ANIMAL BEHAVIOUR_ I. THE PHYSIOLOGICAL ASPECT 295 II. THE BIOLOGICAL ASPECT 305 III. THE PSYCHOLOGICAL ASPECT 315 IV. CONTINUITY IN EVOLUTION 324 INDEX 338 ILLUSTRATIONS FIG. PAGE 1. _Paramecium_. (From “Animal Biology.” Longmans) 4 2. Behaviour of Paramecia. (After Jennings, _American Journal of Psychology_) 8 3. Cell-division. (From “Animal Biology.” Longmans) 13 4. Wapiti with antlers in velvet. (Drawing by Mr. Charles Whymper, after photograph by Miss Reynolds) 16 5. Wapiti with velvet shredding off. (Drawing by Mr. Charles Whymper, after photograph by Miss Reynolds) 17 6. Sun-dew leaf and tentacles. (From Darwin’s “Insectivorous Plants.” Murray. By kind permission of Mr. Francis Darwin, F.R.S.) 26 7. Venus’s Fly-trap. (From Darwin’s “Insectivorous Plants.” Murray. By kind permission of Mr. Francis Darwin, F.R.S.) 27 8. Flower of _Valisneria_ 28 9. Flower of _Catasetum_ 30 10. Flower of _Catasetum_ dissected. (From Darwin’s “Fertilization of Orchids.” Murray. By kind permission of Mr. Francis Darwin, F.R.S.) 31 11. Solitary Wasp stinging Caterpillar. (After Plate III. in Dr. and Mrs. Peckham’s “Solitary Wasps”) 75 12. Solitary Wasp dragging a Caterpillar to its Nest. (After Plate IV. in Dr. Peckham’s “Solitary Wasps”) 76 13. Insect Larvæ: _Sitaris_, _Argyromœba_, and _Leucopsis_. (After Fabre “Souvenirs”) 80