No. 576] 



VARIATION IN DROSOPHILA 



737 



to obtain Ebony flies with Beaded wings have failed. The 

 possibility that for some "inherent peculiarity" an 

 Ebony fly can not have Beaded wings has suggested itself, 



TABLE XXII 



Back-crosses of F, Beaded Males of the Cross Beaded <J X Sepia $ to 



and although this would seem very improbable, it may 

 nevertheless be the fact. At any rate, it appears that 

 Beadedness either depends on genes which in the presence 

 of the Ebony body color are completely recessive, or that 

 the third chromosome gene for Beadedness, B', lies so 

 close to that for Ebony that cross-overs are extremely 

 rare even in the female. 



TABLE XXIII 

 F 2 Results of the Cross Beaded $ X Ebony (J 



151 j 17 525 



Very extensive experiments were carried out with Pink- 

 eyed flies. The important facts brought out are presented 

 in condensed form in Tables XIX, XX, and XXIV-XXIX. 



In Table XXIV are shown the F 2 counts for Beaded by 

 Pink Ebony. From the eleven Pink Beaded flies obtained 

 a new stock was derived, which was "purified" by a few 



TABLE XXIV 



