Wilcox — Spermatogenesis. 



PLATE IV. 



Caloptenus femur-rubrum. 



Figs. 139-158. Spermatid metamorphosis. 



Figs. 159, 160. Spermatocytes, first division. 



Fig. 161. Spermatocyte, preparatory to first division. 



Figs. 162, 163. Spermatocytes with chromatin in dumb-bell stage. 



Figs. 164-171. Spermatogonia. 



Figs. 172-176. Spermatocytes, stages in ring formation. 



Fig. 177. Spermatocyte, first division. One centrosome is cut away in 



another section. 



Figs. 178-183. Spermatocytes, ring stages. 



Figs. 184-188. Spermatocytes, spirem stages. 



Fig. 189. Spermatogonium, tripolar division. 



