No. 644] MUTANT CHARACTERS IN DROSOPHILA 223 



the region of the posterior cross-vein, and to the loss of 

 a section from the outside of the wing between the distal 

 ends of the second and third veins (compare Figs. 5 and 

 6). Beaded flies have poor viability, and the females are 

 sterile. Beaded is similar in appearance to the melano- 



gaster cutg although the latter is slightly more extreme 

 than beaded. While cute Ai^s are vigorous and fertile, 

 some of the cut allelomorphs are not completely fertile 

 and have poor viability.^ 



Orighi. — An out-crossed female, known to carry small- 

 bristle rough on one X-chromosome, and small-bristle 

 orange short-3 on the other, produced offspring in which 

 the small-bristle rough males were also beaded. This fe- 

 male was almost certainly heterozygous for the new gene. 

 Nine sisters were bred separately but no beaded flies ap- 

 peared in their offspring. 



