84 



SEX INHERITANCE 



wild type A. grossulariata is crossed to the rare mu- 

 tant type A. lacticolor. 



LACnCOLOR $ 



GROSSULARIATA cf 



0(D 



EGGS O i) 



© © 



© © SPERM 



Fig. 30. — Abraxas lacticolor female bj'^ A. grossulariata male. The sex 

 chromosomes are represented by the circles in the center of the diagram, 

 and the letters contained in them stand for the factors that each carries. 

 The W chromosome, confined to the female line, is represented without 

 either G or L; for it, like the Y chromosome in Drosophila, carries no sex 

 linked factors. 



