Bristle pattern of tarsal segments T2, T3 and T4 is transformed to that of T1. Homozygous males have ectopic sex combs in tarsal segments 2, 3 and occasionally 4, and fusion of tarsal segments 4 and 5. Additionally the two segments of the antennal basal cylinder are fused. Heterozygous males have an ectopic sex comb on tarsal segment 2.