The total number of bristles on the basitarsi of the second legs is reduced. The number of bractless bristles on the basitarsi remains normal. Significantly more bristles are missing from the anterior side of the basitarsus than from the posterior side. One or the other of the distal sensilla is sometimes missing, and an ectopic sensillum sometimes forms proximally between bristle rows 3 and 4.
ac2, sc3 double mutant removes all bristles except scutellars and postdorsocentrals. ac2/ac2 and ac2/+ suppress h1. Viability of males low; females nearly inviable. RK2.