224 



SABRA COLBY TICE. 



barred males all the offspring were narrow barred. This stock 

 has since bred true. 



RED-BARRED EYE BY WHITE NORMAL EYE. 



The original barred male was crossed with white-eyed females, 

 with the results given in Table IV. The FI 9 9 were red barred, 

 and the FI o 71 cf were white normal, since white is a sex-linked 

 character. The F 2 generation consisted of four classes, red 

 barred, white barred, red normal, white normal, with an equality 

 of males and females in each. The ratios of the four classes w r ill 

 be discussed later. In the following analyses, w is the factor 

 for the recessive white (sex-linked) and W is its normal allelo- 

 morph (red). 



TABLE IV. 



Pi White normal 9 , X w br' X w br' . 



Red-barred d\ X W Br' . 



Fi Females. Fi Males. 



'X w br' JX w br' 



X W Br' t - 



Red Barred 9 . White Normal d*. 



483 440 



Gametes of Fi barred 9 X w br'X W Br'X w Br'X W br' . 

 Gametes of Fi white cT X w br'. 



Females. 



F2 Males. 



The white heterozygous barred females (2 above), bred to 

 their white barred brothers, gave the expected proportions (Table 



V.). 



