Homozygotes cannot fly, their movement is sluggish and they have reduced viability. They generally have unexpanded and unextended wings, although approximately 43.0% of females and 5.9% of males have an incompletely expanded and inflated "balloon" type wing, and occasionally flies have fairly well expanded wings, or shrunken thread-like wings which are orientated slightly downward. The tibia and femur of the second and third legs are completely formed but are not well extended. This defect is strongest in the third legs. The posterior end of the scutellum is indented and the postscutellar bristles are vertically oriented and cross each other near their bases. The thorax-abdomen junction is broader than normal. High temperature (30^oC) given on the second day of pupariation slightly increases the fraction of flies with better expanded and extended wings.

low male viability Wings incompletely expanded as in a newly emerged fly, about one-half normal length, and frequently inflated. Tibiae and tarsi of third legs irregularly shortened and gnarled. Posterior scutellars convergent.