A–F, Confocal images of early pupal Voila1/UAS–GFP expression pattern. A, At puparium formation, expression appears in the third leg disks in two distal clusters of cells (arrowheads) with axon-like processes (arrow). B, At 2 hr APF, two nerves are visible in the elongating leg (arrowheads).C, At 4 hr APF, leg segmentation begins (arrowheads). D, In wing disks, initial expression is seen at 8 hr APF in regularly spaced groups of cells along the anterior margin (arrowheads).E, At 16 hr APF, the clusters of cells are clearly revealed as wing sensilla. Their distribution coincides with the adult pattern of approximately 30 chemosensilla on the dorsal triple row (arrowheads) and approximately 12 chemosensilla on the ventral triple row (arrows). F, At 24 hr APF, the strong staining pattern in legs (arrowheads) and wings (arrows) is reminiscent of the pattern of chemosensilla. Scale bar, 100 μm.