4 6 



P. W. WHITING. 



By expectation from sex-linkoid inheritance the daughters 

 should carry orange, the sons should be without it. The domin- 

 ance of black was complete. Four isolated daughters bred as 

 follows : 



The excess of orange over the expected one to one ratio 

 indicates that orange is not deficient in viability. 



Eight daughters that had mated with their brothers bred as 

 follows : 



The failure of orange to appear in the females is to be expected 

 from sex-linkoid inheritance. 



The mutant orange male was crossed successfully to three of 

 his heterozygous daughters and produced offspring as follows: 



Here in accordance with expectation the orange-eyed females 

 appeared for the first time. In eye color they resembled the 



