Fig. 3. Ectopic msh produces symmetrical dorsal-dorsal wings. c765-Gal4/+; UAS-msh/+ wing. All features are of dorsal identity. In the anterior wing margin each surface differentiates two rows of bristles: a row of densely packed mechanosensory bristles and a row of chemosensory bristles. The pattern of vein L3 corrugation, shown in the diagram, is completely dorsal (d) on both surfaces. The alula differentiates almost no bristles in the ventral surface.