Ferrv, Lancefield and j\Ietz: Mutations in Drosophila 377 



Circular (cr). 



Description. — The wings are circu- 

 lar, and often balloon shaped ; and the 

 entire fly is small. As it had very poor 

 viability, it was difficult to breed and 

 the stock has been lost. 



Origin. — (W294). Several males 

 and females were obtained from a mat- 

 ing for sex-ratio. 



Knotted (K). 

 Figure 17, No. 9 



Description. — Knotted affects all the 

 veins of the wings. They are enlarged 

 irregularly into knots, especially where 

 they meet each other or meet the mar- 

 ginal vein. There may be extra veins 

 present as branches from the main 

 veins, and the cross-veins may be gone 

 or may be close together, like approxi- 

 mated. The marginal hairs are present 

 in clumps giving the edge of the wing 

 a fringed appearance. The wing is 

 sometimes cut off square at the tip or 

 it may be turned up at the tip instead 

 of Iving down over the abdomen as 

 the normal wing does. The wings also 

 are often smaller than normal. The 

 character is a dominant and the flies 

 have poor viability. 



Origin.— (W922. L581). One knot- 

 ted male and one knotted female were 

 found in the first generation of a mat- 

 ing of rough rosette by morula. 



Comparison. — Knotted resembles delta 

 in D. simnlans"' in having the first vein 

 thickened ; the second vein frequently 

 thickened at the end. and sometimes 

 throughout the whole vein ; and the 

 others sometimes thickened. Like delta 

 it is an autosomal dominant, and the 

 flies have poor viability. Knotted dif- 

 fers from delta in not having a branch 

 on the posterior cross-vein; in not hav- 

 ing the wing-margin cut or nicked ; in 

 not having sterile females ; and in hav- 

 ing normal bristles on the scutellum. 



cupped and Scalloped (CI and SI). 

 Figure 16, Nos. 5 and 6 



Description of Clipped. — Clipped is 

 a dominant character, distinguished by 

 variable incisions on the inner margin 

 of the wing as shown in Figure 16. 



Presumably the gene is lethal when in 

 the homozygous condition, for matings 

 of clipped by clipped give approxi- 

 mately a 2:1 ratio, and selection (in 

 keeping stock) for forty-four genera- 

 tions has failed to give a homozygous 

 stock. 



Origin of Clipped.— (W1828 ) . Many 

 males and females were found in a 

 mating of rough by scu4:e short-3. 



Description of Scalloped. — The char- 

 acter scalloped agrees in all respects 

 with clipped and is probably due to the 

 same gene (or an allelomorph), al- 

 though this assumption has not yet 

 been tested adequately. 



Origin of Scalloped.— (W1854:,. 

 Many males and females were found in 

 a mating of rough by scute short-3. 



Apterous (ap). 



Description. — Apterous is charac- 

 terized by the entire absence of wings, 

 by greatly reduced balancers, by the 

 square rather than pointed scutellum, 

 and by the absence of scutellar bristles 

 (in most cases). In addition, the 

 thorax is sometimes greatly deformed. 

 Since both sexes are sterile the char- 

 acter is very difficult to keep in stock. 



Origin. — (R64). Several females 

 w^ere found in the rough clipped stock. 

 Later a few were found in the rough 

 scalloped stock. 



Comparison. — Apterous flies have 

 been found in other species of Droso- 

 phila (e. g., D. melanogaster') but the 

 difficulties of breeding have made de- 

 tailed linkage studies impracticable, and 

 comparisons may be omitted here. 



Ragged (rg). 

 Figure 16, No. 8 



Description. — The margin of the 

 wing is cut irregularly on each side of 

 the tip and the marginal hairs are pres- 

 ent in clumps along the part of the 

 edge which has not been cut. 



Origin. — (R1155). Several males 

 and females were found in a hetero- 

 zygous stock carrying combined. 



Red (red) 



Description. — Red is an eye color 

 character. The eve is a darker and 



