Strap-like wings. Homozygous females have a less extreme phenotype than their hemizygous brothers.

Ectopic bristles are often clustered along the wing veins.

Flies have an extreme scalloped phenotype. The wings are reduced to vestiges in hemizygous males, and are narrow and strap-like in homozygous females. One or both scutellar bristles are sometimes truncated, and halteres appear somewhat reduced in males. The severity of the wing phenotype may vary somewhat with temperature and culture conditions.

Extreme allele of sd associated with the insertion of a P element carrying ry⁺ at 13F. In hemizygous males, wings reduced to mere vestiges similar to vg; in homozygous females the wings are narrow and strap-like. One or both scutellar bristles are sometimes truncated and halteres appear somewhat reduced in males. Severity of wing defect may vary with temperature. Under dysgenic conditions, excision of the P element leads to the loss of ry⁺ and amelioration of the sd phenotype (i.e., wild type or nibbled wings); the molecular lesions of a number of such derivatives have been characterized (Daniels, McCarron, Love, and Chovnick, 1985). One derivative was used as a 'tag' for cloning the sd region (Campbell, Duttaroy, Katzen, and Chovnick, 1991).