stage 4 neuroblast A neuroblast delaminating in the fourth wave of neuroblast delamination from the ventral neurectoderm. This wave begins during embryonic stage 11, ending in late stage 11. The S4 neuroblasts delaminate into columns in between the existing intermediate and lateral columns of neuroblasts (Doe, 1992). VFB:FBbt_00001409 S4 neuroblast FBbt:00001409 fly_anatomy.ontology neuroblast