No. 583] BOLE OF ENVIRONMENT IN DROSOPHILA 



409 



TAP.LE XVII 



TESTS OF CHANGED-OVEB CLASSES 



In a number of cases in which some members of an ab- 

 normal class changed over to become phenotypically 

 members of a normal class; some of these apparently 

 normal flies were tested under conditions favorable for 

 the appearance in the next generation of abnormality. 



