192 DISTRIBUTION OF THE CHROMOSOMES 



a a' 







iv* .* ••%•>•• 









• • 







• • • • • 



C 



Fig. 48. — Biston hirtaria; a, spermatogonia! chromosomes; a', primary 

 spermatocyte chromosomes (reduced number). Biston zonaria; h, sper- 

 matogonia! chromosomes; b', primary spermatocytes (reduced numlier). 

 Hybrid, out of zonaria fema!e by hirtaria ma!e; c, spermatogonia! chro- 

 mosomes; c', primary spermatocytes. (After Harrison and Doncaster.) 



