554 



MARY B. STARK 



TABLE 17 (a) 

 White eyed granddaughters of sister and brother by a white eyed miniature male 



had taken place, except when crossing over occurred again in 

 the mother. This was tested (table 17b). 



TABLE 17 (b) 

 Red eyed granddaughters of sister and brother by white eyed miniature male 



Four of the red eyed females gave a 2 : 1 ratio indicating that 

 crossing over did occur in the mother. 



To determine whether this lethal is the new one or the original 

 one whose locus was shown to be at 23.7 the white eyed females 

 were mated to eosin^ to find the locus of the factor in the chromo- 



3 Eosin is an allelomorph of white. A female that has the eosin factor in one 

 X and the white factor in the other X can be distinguished from a pure female 

 with eosin in both X's. 



