LINKAGE VARIATION IN DROSOPHILA 



15 



sing e exceptional rise in the percentage in the case of bar fused 

 is probably not significant, since the same females gave no rise 

 but a fall in the case of other gens, and the distance involved 

 is so small (2.3 units) that a very few flies make a great apparent 

 difference. 



THE THIRD CHROMOSOME DATA 



For the third chromosome I am now able to report only the 

 single case of pink and kidney (table 19). Here four of the 

 five second broods showed rises, and only one a fall. The 

 totals show a rise of 2.4 units, or of 17.1 per cent, on the basis 

 of the first broods. This case in itself is too small for any con- 

 clusion to be drawn. It is possible, however, that in the case 

 of the third chromosome a rise from first to second broods may 

 occur. 



TABLE 19 

 Pi wild X pink kidney. B.C. F\ wild type 9 X pink kidney cf c?" 



