298 ELIZABETH A. SMITH. 



PLATE IV. 

 Sympetrum semicintum (Say). 



FIGS. 45, 46, AND 47. Side views of metaphase of primary spermatocyte divi- 

 sion. 



FIG. 48. Anaphase of primary spermatocyte division. 



FIGS. 49, 50, 51 AND 52. Telophases of primary division. 



FIG. 53. Polar view of telophase of primary division which shows the sex- 

 chromosome at one side. 



FIGS. 54, 55, 56 AND 57. Polar view of chromosomes of secondary spermatocyte. 



FIGS. 58, 59, 60, 61 AND 62. Metaphase views of secondary spermatocyte 

 divisions with the sex-chromosome in various positions. 



FIGS. 63. 64. Telophases of secondary spermatocyte division. 



FIG. 65. Metaphase of secondary spermatocyte division from aceto-carmine 

 smear. 



FIGS. 66 AND 67. Polar view of telophase of secondary spermatocyte division 

 showing sex-chromosome. 



FIGS. 68, 69 AND 70. Spermatids. 



FIG. 71. Spermatid showing tail filament. 



FIGS. 72 AND 73. Spermatids which have elongated and formed head spines. 



FIG. 74. A sperm head from a smear preparation. 



FIGS. 75 AND 76. Cross-section of spermatozoa to show the chromatin con- 

 densed around the nuclear wall. 



FIGS. 77, 78 AND 79. Spermatozoa from aceto-carmine preparations. 



