THE PHDOGENETIC FLY, MIASTOR — 55 
(f.n) are produced. The nucleus of the polar body 
divides by mitosis and the two nuclei thus formed 
Fic. 14.— Miastor americana. Longitudinal section through mature 
egg. c=cytoplasm; f.n =female nucleus; n.c = nurse chamber; 
p.b = polar bodies; pPl = pole-plasm. 
remain within the egg substance near the periphery 
for a considerable period (Fig. 14), but finally 
