No. 5S3] ROLE OF ENVIRONMENT IN DROSOPHILA 405 



An examination of Table VI shows how extensively 

 changing took place in almost every one of the experi- 

 ments. The contrast with the result of Table V is very 

 striking. 



L 



>c_>c 



The experiment was made once one way (Table XI) and 

 seven times reciprocally (Table XII). In the first case 



TABLE XI 

 Parents: YWAb $ by GBN<^ 

 F»: GEN $ — YWN <$ 



nearly all of the GRAb females are of the normal type. 

 The only GR males that are abnormal are single cross- 

 overs (Diagram V). This means that the heterozygous 

 females are affected more easily than are the pure male-: 



l slight . 25 

 1 71 

 3 69 



5 ... ... ... 225! 536. 



able, viz., two GWN ?. 



