7.1% of expected mutant embryos hatch as first instar larvae. The latest observed stage of mutants is adult. Nerve cord length is 76% of embryo length. Midline guidance failure of repellence phenotype, evidenced by midline crossing, is moderate. 2.9 ventral oblique muscles per segment cross the midline on the dorsal surface of the ventral nerve cord, instead of having migrated to the edges and inserted into the ectoderm.
Mesectodermal cell distribution is normal. Axon trajectories in the CNS show misdirection towards the midline. The commissural tracts are thickened and show poor definition of anterior and posterior commissures. Longitudinal tracts are thinned. During stage 12/0, pioneers of the longitudinal tracts show misdirection and crossing of the midline. The ventral oblique muscle phenotype of crossing the midline is less marked than for sli2