stage 5 neuroblast neuroblast NB4-3 neuroblast NB4-3 FBbt:00001423 NB 21 lineage NB4-3 neuroblast Schmidt et al. (1997) describe this lineage as producing motorneurons that project into the SN. Contrarily, Schmid et al. (1999) suggest that the cells identified as motorneurons by Schmidt are actually neurosecretory cells of the TN. Neuroblast that delaminates at S5 and generates 2-3 neurosecretory cells that project together out of the CNS via the transverse nerve in addition to interneurons (Schmid et al., 1999). In the embryo, one of these cells can be found in each hemisegment from S1-A9 (Birkholz et al., 2013; Urbach et al., 2016). In the larva, it resumes proliferation in all thoracic segments (Lacin and Truman, 2016). The neurons that develop from this neuroblast after larval hatching form postembryonic lineage 21. fly_anatomy.ontology VFB:FBbt_00001423 lineage 21 neuroblast neuroblast 21 segmentally-repeated neuroblast