FIG. 1. Equatorial plate from somatic tissues of a male pupa, 27 large chromosomes, 1 small one. 2. Equatorial plate from an egg follicle, 28 large chromosomes. 3. Equatorial plate of spermatogonium, 27 large chromosomes, 1 small one. 4. First spermatocyte, synizesis stage. 5. First spermatocyte, early spireme stage, showing unequal pair of chromosomes. 6-7. First spermatocyte, later growth stages. 8. First spermatocyte, prophase. 9-12. First spermatocyte, metaphase. 13. First spermatocyte, equatorial plate. 14-15. First spermatocyte, anaphase, showing separation of the elements of the unequal pair (_l_ and _s_). 16. First spermatocyte, daughter plates. 17. Second spermatocytes, equatorial plates. 18. Second spermatocytes, equatorial plates showing V-shaped chromosomes. 19. Second spermatocyte, early anaphase, the small chromosome in metakinesis. _Trirhabda canadense._ 20. Equatorial plate from egg follicle, 30 large chromosomes. 21. Equatorial plate of spermatogonium, 29 large chromosomes, 1 small one. 22. First spermatocyte, growth stage showing the heterochromosome group. 23. Heterochromosome group. _p_ = plasmosome, _l_ = large heterochromosome, _s_ = small heterochromosome. 24-27. First spermatocyte, metaphase. 28. First spermatocyte, equatorial plate. 29. First spermatocyte, equatorial plate, small member of the unequal pair only present. 30. First spermatocyte, daughter plates. 31. Second spermatocytes, equatorial plates. 32-33. Second spermatocytes, prophase. [Illustration: STEVENS PLATE VIII N. M. S. del. COLEOPTERA] PLATE IX. _Chelymortha argus_ (_Family Chrysomelidæ_). FIGS. 34-35. Equatorial plates from egg follicles, 11 equal pairs, no small chromosome. 36. Equatorial plate of spermatogonium, 21 large chromosomes, 1 small one. 37. First spermatocyte, synizesis stage. 38-40. First spermatocyte, synapsis stage. 41-43. First spermatocyte, bouquet stage after synapsis. 44-45. First spermatocyte, spireme stage showing the unequal pair of heterochromosomes. 46. First spermatocyte, prophase. 47-49. First spermatocyte, metaphase. 50-51. First spermatocyte, equatorial plates, _x_ the heterochromosome pair. 52. First spermatocyte, showing metakinesis of the unequal pair. 53. First spermatocyte, anaphase. 54-55. Second spermatocyte, equatorial plates. 56. Second spermatocyte, anaphase. _Odontota dorsalis_ (_Family Chrysomelidæ_). 57. Equatorial plate of male somatic cell from walls of the testis, 15 large chromosomes, 1 small one. 58-59. Equatorial plates of spermatogonia, 15 large chromosomes, 1 small one. 60. Resting nucleus of spermatogonium, showing plasmosome (_p_). 61. First spermatocyte, synizesis stage. 62. First spermatocyte, synapsis stage. 63-64. First spermatocyte, spireme stage, showing the larger and smaller heterochromosome associated with a plasmosome. 65-68. First spermatocyte, prophases. [Illustration: STEVENS PLATE IX. N. M. S. del. COLEOPTERA] PLATE X.