Mutant mushroom body neuroblast clones generated in newly hatched larvae and examined in the wandering third instar overextend processes from the calyx. Mutant mushroom body neuroblast clones generated in newly hatched larvae and examined in the wandering third instar show a mild reduction in cell number compared to control clones. Adult mushroom body neuroblast clones consist mainly of γ neurons, with a few α'/β' neurons.