16 



Linkage Group I. 



filled with liquid, but usually there is only a small blister, or perhaps two near the 

 center of the wing. Frequently only one wing is affected, and ordinarily in from 1 

 to 5 per cent of the cases both wings appear to be normal. The viability of vesicu- 

 lated stock is good, and aside from the inconstancy just mentioned the character is 

 good for linkage studies. 



Origin. — (V 290.) Several males were obtained from a mass culture (see Metz, 

 1918, p. 107). 



Comparison. — Vesiculated suggests "inflated" in D. melanogaster (Weinstein, 

 1918), "bubble" in D. simulans (Sturtevant unpublished data), and "inflated" in 

 D. funebris (Sturtevant, unpublished data). 



Fig. 4. — Singed. 



Oblique (o). (Plate 2, Figures 3 and 4.) 



Description. — Oblique males differ from normal in nearly all parts of the body. 

 In size they are smaller; in body-color considerably darker; in eye-color extremely 

 dark, becoming almost black with age. The body is much shorter and stouter than 

 usual, the wings are short, broad, and sometimes obliquely blunted instead of being 

 rounded (fig. 3, plate 2), and usually hang do\vn over the sides of the abdomen, 

 roof-like, instead of being held horizontally. The fifth vein is often short and the 

 posterior crossvein is often broken or wanting. Oblique females are sterile and conse- 

 quently pure stock has not been obtained. The name of this character was taken 

 from its appearance in combination with short. In this combination both char- 

 acters are exaggerated; the wings are frequently very short and cut off obliquely at 

 the tips (fig. 4, plate 2), and the veins are shortened more than in ordinary "short" 

 flies. 



Origin. — (M 47.) 16 oblique males were found among the offspring of 2 females 

 heterozygous for vermilion and short. 



