Davis. — Spermatogenesis. 



PLATE 5. 



Figs. 69-73. Steiroxys trilineata. 



Fig. 69. Stage e, primary spermatocyte. The monosome is seen above and 

 at the left. 



Fig. 70. Stage g, primary spermatocyte. The monosome is seen at the 

 lower side of the nucleus. 



Figs. 71, 72. Stage h, primary spermatocyte. The monosome is distin- 

 guished from the autosomes by its more compact structiu-e. 



Fig. 73. Metaphase of first maturation division. Tlae monosome is con- 

 nected with only one pole. 



Fig. 74. Metaphase, first division of Melanoplus femoratus. The mono- 

 some is seen at the right connected with only one pole. 



Figs. 75-81. Dissosteira Carolina. 



Fig. 75. Semiresting stage of second spermatocyte. The monosome is seen 



below in the figure and at a lower focus. 

 Fig. 76. Prophase of second division. 

 Fig. 77. Metaphase of second division. 

 Figs. 78-79. Anaphase of second division. The figures are from two 



successive sections of the same cell. All the chromosomes 'are 



shown. 

 Fig. 80. Telophase of second division. 



Fig. 81. Spermatids. The monosomes still retain their compact st'-ucture. 

 Fig. 82. Spermatid of Stenobothrus cvrtipcnnis. The monosome is still 



compact. 



