Plate I 



Musca domestica 



Fig. I Spermatogonium, prophase, five equal pairs and one unequal pair of chromosomes. 



Fig. 2 First spermatocyte, growth stage. 



Fig. 3 First spermatocyte, prophase. 



Fig. 4 First spermatocyte, anaphase. 



Figs. 5 and 6 Second spermatocytes, prophase. 



Figs. 7 and 8 Second spermatocytes, anaphase. 



Fig. 9 Oogonium, metaphase. 



Calliphora vomit or ia 



Fig. lo Spermatogonium, metaphase. 



Fig. 1 1 First spermatocyte, growth stage. 



Figs. 12 and 13 First spermatocyte, metaphase. 



Fig. 14 First spermatocyte, anaphase. 



Figs. 15 and 16 Second spermatocyte, metaphase. 



Fig. 17 Second spermatocyte, anaphase. 



Figs. 18 and 19 Oogonia, metaphase. 



Lucilia casar 



Fig. 20 First spermatocyte, growth stage. 

 Figs. 21 and 22 First spermatocyte, metaphase. 

 Figs. 23 and 24 Second spermatocyte, prophase. 



