Davis.— Spermatogenesis. 
PLATE 7. 
Fias. 99-111. Successive stages of the monosome in the primary sperma- 
k tocytes of Dissosteira carolina. 
Fias. 112-114. Monosomes of Arphia tenebrosa during the late growth period. 
Fias. 115-124. Successive stages of the monosome in the primary sperma- 
tocytes of Melanoplus femoratus. 
Fias. 125-150. Successive stages of the monosome in the primary sperma- 
tocytes of Stenobothrus curtipennis. 
Figs. 151-158. Successive stages of the monosome in the primary sperma- 
tocytes of Steiroxys trilineata. 
Fic. 159. Rod-shaped tetrad of Hippiscus tuberculatus. 
Figs. 160-182 Dissostiera carolina. 
Fies. 160-164. Suecessive stages of the rod-shaped type of tetrads. 
Fias. 165-168. Successive stages of the cross-shaped type of tetrads. 
Fic. 169. Extreme development of cross-shaped type of tetrad. 
Fies. 170-174. Successive stages of ring-shaped tetrads. 
Figs. 175-182. Successive stages of the crossed loops. 
Fies. 183-188. Large loops of Stenobothrus curtipennis. 
