Extreme wing reduction especially in the posterior compartment. Half of the flies have duplications of the anterior wing margin, distal costa and triple row bristles. Little venation is present. Some flies have defective third legs (more frequent in females than males). Halteres and scutellar bristles appear normal.

Homozygotes display extreme wing reduction, particularly of the posterior wing compartment. Approximately 50% of the flies have duplications of the anterior wing margin, distal costa and triple row bristles. In wings with large amounts of wing blade, very little venation is present; however, these may often have triplications or even four copies of the anterior wing margin, some located in the posterior part of the wing. Dried hemolymph sometimes trapped between the dorsal and ventral wing surfaces giving the wing a puffy blackened appearance. This mutant therefore has duplications and deficiencies characteristic of cell death followed by regulation in the wing, but also has transformations of the posterior wing compartment to the anterior wing compartment. 8% of the flies have defective third legs, more frequently in females than in males. Halteres and scutellar bristles appear to be normal.