Fig. 1. Dm myb mutants have missing and improperly oriented abdominal bristles, and patches of undifferentiated tissue. (A-H) Comparison of wild-type and mutant abdomens. Dorsal (A-D,H) and ventral (E-G) cuticles from female adult abdomens: control w/Df(1)sd^72a (A,E) flies raised at 24°C; myb² (B,F) flies raised at 24°C; (C) myb¹ raised at 18°C; (H) esg mutant (esg^k0060/Df(2L)TE35D-2) raised at 24°C; pharate adults of myb²/Df(1)sd^72a raised at 24°C (D); and pharate adults of myb² raised at 28°C (G). (I-L) Comparison of wild-type and mutant abdominal histoblast nuclei in third instar larvae raised at 24°C. All nuclei within the field were visualized by DAPI staining. (I'-L') Abdominal histoblast nest cells were identified by using ß-galactosidase antibodies and the enhancer trap insert esg^P3. (I) Control w; esg^P3/+; (J) myb²; esg^P3/+; (K) myb²/Df(1)sd^72a; esg^P3/+; (L) esg^VS8/esg^P3. Scale bars: in A, 0.5 mm for A-H; in I', 0.05 mm in I-L'.