PLATE 7 



STUDIES ON GERM CELLS 



ROBERT W. HEGNER 



41 Compsilura concinnata; section through 44 Section through an egg containing one 



posterior end of egg showing formation of polar body (p.b), a female nucleus, and two 



primordial germ cells (p.g.c) 



42 A slightly later stage than in figure 41. 



43 Cecidomyia strobiloides ; section through 

 posterior end of egg just before deposition. 



44-55 Calligrapha. 



spermatozoa (s). 



45 The fusion of male and female nuclei. 



46 Egg containing two polar bodies and 

 two cleavage nuclei. 



47 Egg containing four cleavage nuclei. 



506 



