Aristae tarsuslike with fused, distorted joints and terminal claws. Bristles reduced to vestiges and hairs short. Wings spread and drooping. Tarsal joints of legs fused, swollen, and distorted. Viability low; fly sterile. ssa53e/ssa like ssa. ssa53e/ssiso53 has fleshy proximal segments of aristae. RK2.
Piternick, 1953.