BRISTLE INHERITANCE IN DROSOPHILA 



71 



averages (fig. 3 and table 8) show that this is not the case. The 

 averages for females range from +2.83 to +4.05. This set of 

 families gives some idea as to how much variation is possible 

 when the grandparents are brother and sister and the parents 

 all sibs of the same grade. 



In Fe are two sets of cousins. In one group are five families 

 (fig. 3B), grandchildren of 115, with parents of various grades. 

 Considering the female averages (table 8B) it is seen that the 

 parental sums of 7, 8a, and 12 give similar filial averages, whereas 

 the parental sums of 8b and 14 give higher averages. Con- 

 sidering the males, parental values of 7, 8b, and 12 give similar 



TABLE 8 



Six groups of cousins. In each group the parents are sibs; grades of parents and 

 means of offspring arranged according to the sums of the parents' grades. See 

 figure 3 



