SEX-LINKED INHERITANCE IN DROSOPHILA 



93 



direction. The recessive RB combination may be obscured by 

 the red, nor^mal or black, female classes. 



Concerning the cases of crossing-over for character of wing 

 SWN c^ = 418, while LWN ^ = 224; SWR d' = 145, while 

 LWB cf = 95. On the other side, LRY d^ = 419, while SWY ^ 

 = 161 • LRBr c? = 102, while SRBr c? = 47. The sum of the 

 'straight' males is 1081, and that of the cross-overs 527; or almost 

 exactly 2 to 1. 



The reciprocal cross is as follows: 



SWB d" by LRY 9 



