VG+ cells in cluster vi are mVUMs. A, Two-cell GFP+ clone in A8 of a stage 17 embryo includes one VG+ cell of cluster vi (arrowhead). B, The axon projected by this clone extends to the anterior (small arrow), and branches twice. C, Photomontage of clone cell bodies shown in B and axonal morphology of this clone. The first branching event produces two projections with complex arborizations at the lateral ends (small arrows). The second branching event results in long axons that extend on either side of the midline, each forming a broad ‘U’ (large arrows). We propose that the large axon marked by the large arrows is extended by the VG+ cell (arrowhead, B), which is MzVUM, and the shorter axons are extended by its sibling iVUM, which does not express VG.