THE AMERICAN NATURALIST 

 Parents: AbE by NE 



all normal ; these inbred gave in F 2 the classes given above : 

 Two eosin females heterozygous for white were crossed 

 each to an abnormal male. The normal F x daughters 

 were bred to those sons that had white eyes, and gave the 

 following kinds of offspring : 



Abnormal males were bred to eosin females and gave, as 

 before, normal F x sons and daughters. Some of the 

 daughters were backcrossed to eosin cream abnormal 

 males and gave the following results : 



These tables show that the abnormal condition rarely ap- 

 pears in F 2 . Its realization must be due therefore either 



