Wilcox. — Spermatogenesis. 



PLATE 1\1. 



Caloptenus femur-rubrum. 



Figs. 105-107. Spermatogonia. 



Fig. 108. Longitudinal section of testicular follicle, a, spermatogonia ; b, growth 

 zone of spermatocytes; c, first division of spermatocytes; (/, first stages 

 of spermatids ; e, later stages of spermatids;/, abortive spermatogonia. 



Fig. 109. Cross -section of vas deferens containing spermatozoa. 



Figs. 110, 111. Spermatocytes in the spirem stage. 



Figs. 112, 113, 117, 118, 122, 123. Spermatocytes in the first division. 



Fig. 114. Spermatocyte of the first order before dumb-bell stage of chromatin. 



Figs. 115, 116. Spermatocytes of the first order in the dumb-bell stage of chromatin. 



Figs. 119-121, 124. Spermatogonia in division. 



Figs. 125, 12(5, 129. Spermatids just after division of the spermatocytes of the 

 second order. 



Fig. 127. Spermatocyte, first division. 



Fig. 128. Spermatocyte, second division. 



Fig. 130. Spermatocyte before first division. 



Fig. 131. Spermatogonium, polar view of spindle. 



Figs 132-138. Spermatogonia in division. 



