macrochaeta & scutum
ara1 caup1/Df(3L)iro-2 flies lack lateral macrochaetae and the most lateral of microchaetae of the notum. The humeral bristles are normal and have wild-type axonal projections in these flies although the humerus is not morphologically normal. Bristles of variable size are formed in the otherwise naked lateral region of the notum if the flies are also carrying acHw-49c, at a position corresponding to that of the posterior supraalar bristle. This bristle has a contralateral axon branch in about 70% of cases.
ara1/ara1 flies carrying schs.PR develop tufts of bristles in the lateral part of the notum (that is normally naked in ara1 homozygotes) after heat shock. Double heterozygotes with Df(4)M101-62f or Df(1)260-1 have a much stronger phenotype, with some bristles missing at a high frequency.