Wing veins of ab60M/abG9 heterozygous adults are absent between the margin and the posterior crossvein; thoracic and wing mechanosensory bristles are missing; occasionally one of the campaniform sense organs on wing vein L3 is absent; legs are gnarled and the more distal segments are reduced in length or absent; male genitalia rotated.
Alleles fall into an allelic series with respect to wing venation and bristle defects: ab1/ab1 = ab94/ab94 < ab1/ab60M = ab1/abG9 < ab1/ab1D = ab1/abG5.