The progeny of neuroblasts NB 3-5 and NB 7-3 show mostly normal axonal projections in stage 16 mutant embryos. However, axons have abnormal varicosities and additional small ectopic side branches. Alterations in the structure of the growth cones are seen; they appear enlarged with sometimes extensive, filopodia-like processes.

Fas2-positive axons occasionally cross the midline in β-Spec^unspecified stage 16 embryos.

Mutant larvae often fail to hatch. Newly hatched larvae initially crawl, eat and respond to touch, but grow increasingly sluggish over time, fail to grow and eventually die.

Commissures appear to be of uneven thickness in stage 13 embryos and the RP1 neurons appear closer to the midline than normal. Some commissural axons directly turn to cross the midline again, instead of projecting further laterally to grow along the forming longitudinal tracts, resulting in a "circling axon" phenotype. The longitudinal connectives do not form properly. A small set of normally ipsilateral axons project contralaterally in mutant embryos.