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THE AMERICAN NATURALIST [Vol. XLVIII 



since they are similar to previous results in showing no 

 linkage. A winged, pink-eyed male bred to an apterous, 

 vermilion-eyed female (from Experiment III) gave, as 

 expected, winged, vermilion-eyed males and winged, red- 

 eyed females in F x . These inbred gave four classes of 

 winged and four classes of apterous, i. e., red, vermilion, 

 pink and orange. 6 The ratios are such as to show inde- 

 pendent segregation of apterous and pink. Below is a 

 summary of the expected and actual results. 



P x Apterous, vermilion $ a v vPX-a P vPX, 

 Winged, pink $ A P VpX-A P p. 



F x All winged. Eed $ a P vPX-A P V P X, 

 Verm. <$ chvPX-A P p. 



Eight kinds of eggs and four kinds of spermatozoa are 

 formed by these Fj flies, giving, through random fertiliza- 

 tion, 32 classes of offspring divided into eight groups, as 

 shown in Table IV. 



TABLE IV 



In the table red and vermilion have been considered 

 together as one class, because they both contain P; and 

 similarly pink and orange have been considered together 

 because they both contain p. The total numbers for the 

 four classes give the ratios 402:111:114:34, or 10.8:3.6: 

 3.35 : 1,-a sufficiently close approximation to the expected 



