(A) Left: schematic showing spatial positions of NB5-6 and NB7-4. Right: Immunostaining of stage nine embryos showing neuroblast-specific STF expression (En, Gsb) and common TTF expression (Hb). Genotype: en-Gal4/UAS-GFP. (B–D’) NB5-6-Gal4 is expressed in the NB5-6 lineage from stage 10 until the end of embryogenesis. Dan is present in NB5-6 through stage 12 (C’). (D’) Schematic of NB5-6 expression (green outlines) and Hb expression (purple), see text for details. Note that Gal4 expression is present during the Dan + Hb competence window. Genotype: lbe-K-Gal4/UAS-myr::GFP. (E–G’) NB7-4-Gal4 is expressed in the NB7-4 lineage from stage 10 until the end of embryogenesis. Dan is present in NB5-6 through stage 12 (F’). (G’) Schematic of NB7-4 expression (green outlines) and Hb expression (purple), see text for details. Genotype: R19B03AD/UAS-myrGFP; R18F07DBD/+. (H–I) NB5-6 early-born Chaise Lounge neurons. Lateral view, anterior, left. (H) Two segmentally repeated Chaise Lounge neurons labelled by MCFO (hs-FLP lbe-K-Gal4 UAS-MCFO); the Chaise Lounge neurons are Hb+ (inset). Note the ipsilateral projections. (I) Two segmentally repeated Chaise Lounge neurons in the EM reconstruction, where they are named A27k. Inset: outline of CNS with Chaise Lounge neurons shown. (J–K) NB7-4 early-born G neuron. (J) MARCM clone made with en-Gal4 labels most or all of the NB7-4 lineage, including the diagnostic Channel Glia (CG) which are only made by NB7-4 (Schmidt et al., 1997; Schmid et al., 1999). Note the G neuron axon arbors which project the most laterally in the connective and are both ascending and descending (red arrowheads). SPG, subperineurial glia. Dorsal view, anterior to left. (J) The G neuron in the EM reconstruction (red). The neuropil is outlined in gray. Note the lateral axon projection that is ascending and descending, and the cell body position contacting the neuropil. Also note the two small bilateral midline processes, which match those of the grasshopper G neuron (Raper et al., 1983).