ILLUSTRATIONS. . 



Page. 



Fig. 1. Median longitudinal section of body of worker 8 



2. Diagram of generalized insect embryo 12 



3. Example of generalized insect mouth parts 17 



4. Diagram of generalized thoracic segment 19 



5. Typical insect leg -. 2] 



6. Diagram of generalized insect wing and its articulation 22 



7. Diagram of terminal abdominal segments of a female insect and early 



stage in development of gonapophyses 25 



8. Example of a swordlike ovipositor 25 



9. Head of worker bee 27 



10. Heads of worker, queen, and drone 29 



11. Median longitudinal sections of heads of worker and drone 30 



12. Antennal hairs and sense organs 36 



13. Mandibles of worker and drone 40 



14. Internal mandibular gland of worker 42 



15. Mouth parts of worker 43 



16. Median section through distal half of mentum and base of ligula of 



worker 50 



17. Epipharynx and labrum of worker 51 



18. Sense organs of epipharynx 52 



19. Median longitudinal section of head of worker 52 



20. Dorsal view of ventral walls of body of worker 53 



21. Thorax of worker 54 



22. Lateral view of mesotergum of worker 56 



23. Thoracic terga of worker 57 



24. Upper part of left mesopleiu-um of worker 58 



25. Wings of Hymenoptera 60 



26. Basal elements of wings of Hymenoptera 61 



27. Median section through thorax of drone 64 



28. Internal view of right pleurum of mesothorax of drone 65 



29. Legs of worker, queen, and drone 67 



30. Claws and empodium of foot of worker 68 



31. Tarsal clawa of worker, queen, and drone 69 



32. Lateral view of abdomen of worker 70 



83. Ventral view of abdomen of worker 70 



34. Dorsal view of abdominal sterna of drone 70 



35. Sixth abdominal sternum of worker, queen, and drone , 72 



36. Semidiagrammatic view of left side of sting of worker 75 



37. Ventral view of sting of worker 76 



38. Section of small piece of wall of poison sac 79 



39. Sections of alkaline gland of sting 79 



40. Details of sting of worker 81 



41. Tip of abdomen of worker with left side removed 82 



6 



