Fig. 11. (A) Morphology of the adult Drosophila proboscis. Posterior (left) and anterior (right) views (from Kumar et al., 1979). (B) Comparison of the original fate map (left) and molecular maps of wild-type (center) and pb5 (right) labial discs. Note that the Dll (green) expression domain and its function in pseudotracheal formation are not consistent with the positions of the pseudotracheal and border hair anlagen on the original fate map. ALP, anterior labial plate; BH, border hairs; DP, distiproboscis; FU, furca; HS, horse-shoe sclerite; LB, labellar bolster; LC, labellar cap; MP, mediproboscis; PA, prestomal aperture; PM, prementum; PT, pseudotracheae; SB, sensilla basiconica; SS, sigmoid sclerite. The colored domains and shading are the same as those used in Fig. 9 and indicate the accumulation patterns of the appendage patterning genes in the labial discs.