CHAP. PAGE I. Introduction 1 II. Growth and Change 8 III. The Life-stories of some Sucking Insects 16 IV. From Water to Air 23 V. Transformations, Outward and Inward 35 VI. Larvae and their Adaptations 49 VII. Pupae and their Modifications 79 VIII. The Life-story and the Seasons 89 IX. Past and Present--the Meaning of the Story 105 Outline Classification of Insects 122 Table of Geological Systems 123 Bibliography 124 Index 129 LIST OF ILLUSTRATIONS Stages in the Transformations of a Gnat _Frontispiece_ FIG PAGE 1. Stages of the Diamond-back Moth (_Plutella 3 cruciferarum_) 2. Head of typical Moth 5 3. Head of Caterpillar 5 4. Common Cockroach (_Blatta orientalis_) 12 5. Nymph of Locust (_Schistocera americana_) 13 6. _Aphis pomi_, winged and wingless females 19 7. Mussel Scale-Insect (_Mytilaspis pomorum_) 21 8. Emergence of Dragon-fly (_Aeschna cyanea_) 29-31 9. Nymph of May-fly (_Chloeon dipterum_) 33 10. Imaginal buds of Butterfly 39 11. Imaginal buds of Blow-fly 43 12. Carrion Beetle (_Silpha_) and larva 51 13. Larva of Ground-beetle (_Aepus_) 52 14. Willow-beetle (_Phyllodecta_) and larva 53 15. Cabbage-beetle (_Psylliodes_) and larva 54 16. Corn Weevil (_Calandra_) and larva 55 17. Ruby Tiger Moth (_Phragmatobia fuliginosa_) 61 18. Larvae and Pupa of Hive-bee (_Apis mellifica_) 65 19. Larva of Gall-midge (_Contarinia nasturtii_) 68 20. Crane-fly (_Tipula oleracea_) and larva 69 21. Maggot of House-fly (_Musca domestica_) 71 22. Ox Warble-fly (_Hypoderma bovis_) with egg, larva, and puparium 75 23. Pupa of White Butterfly (_Pieris_) 85 CHAPTER I INTRODUCTION