Fig. 1. Cuticular phenotypes associated with tup clones. (A) View of the lateral-posterior region of a notum displaying ectopic structures in a fly bearing f tup² clones. The framed area is shown at high magnification in B, after mounting of the cuticle. (B) S1 and S2, extant first and second axilary sclerites; S1' and S2', recognisable ectopic sclerites; asterisk and tg', mass of sclerotised tissue and an ectopic tegula-like structure, respectively, bearing macrochaetae and sensilla trichoidea. (C) Ectopic tegula (arrow) with ytup^ex4 bristles, and extant tegula (arrowhead). (D) Pedicel of a haltere (asterisk) showing rows of sensilla campaniformia (white arrowheads). Black arrowhead, ectopic structure on the metanotum bearing at its base pedicel-like sensilla campaniformia (arrows). Insets show boxed regions at high magnification. (E) Protuberance on the anterior lateral notum with f tup² microchaetae (arrowhead). (F) Notum showing loss of tissue and of bristles in the scutellum (arrow) and a vesicular invagination (arrowhead). (G) High magnification of the vesicle shown in F. Arrowhead, group of sensilla campaniformia. (H,I) Two focal planes of an invagination with y tup^ex4 microchaetae arising from its interior (arrowhead). Green line, contour of a crinkled (ck)-marked twin-spot which covers the invagination. (J) Cuticular defects (arrow and arrowheads) on the scutum and scutellum of a fly with ftup^isl-1 clones. (K) Protuberance/invagination (indicated by the arrow in J) at high magnification. Note the apical hole of the invagination, and the abutting ck twin-spot tissue in the top-left corner of the panel. (L) Malformation with a central depression and ftup² macro and microchaetae. Red, sensillum campaniforme, as shown at higher magnification in the inset. In K and L, some of the mutant ftup bristles are coloured yellow.