LETHAL FACTOES IN DROSOPHILA 



537 



The following tests were made of the daughters of number 

 12 of 36, table 4: 



TABLE 5— Continued 



36, 12 



In this test there were 5 high to 3 low ratios showing that 

 36, 12 was a lethal bearing female. 



The following tests were made of the daughters of number 

 7 of 47, table 4. 



TABLE ^—Continued 



47, 7 



Here there are 5 high to 3 low ratios indicating a lethal. 



In 47,S the 4 high to 4 low ratios indicate a lethal. 



In 47, 1 there are 3 high to 7 low ratios. Of the three sets 

 of tests of 47 of table 5 there were 12 high to 14 low ratios 

 which establishes the presence of a lethal in this line. The 

 general outcome of these tests leaves no doubt that a lethal was 

 present in the original females that were tested. 



Since only half of the daughters of a lethal female are hetero- 

 zygous for lethal and since these females are indistinguishable 



