We describe in this paper details of morphogenesis of wing hairs in Drosophila pupae. The ultimate objective is to relate specific protein components used in hair construction to specific components produced in the rapidly changing patterns of gene expression that are characteristic for the period of hair differentiation in wing cells (H. K. Mitchell and N. S. Petersen, 1981, Dev. Biol. 85, 233-242). Hair extrusion to essentially full size occurs quite suddenly at about 34 hr (postpupariation) and this is followed by deposition of a double-layer of cuticulin during the next 4 to 5 hr. Extreme changes in shape of cells and hairs, probably related to actin synthesis, then occur for the next 5 to 6 hr. Deposition of fibers within the hairs and on hair pedestals follows. Formation of cuticle on the cell surface begins and continues until some time in the 60-hr range. It appears that cuticle is formed only on the cell surface and not in hairs or on the top of hair pedestals. The protein synthesis patterns associated with these events are described.