The ISN shows three aberrant phenotypes in mutant embryos; failure to reach the final branch point in the dorsal muscle domain, failure to innervate muscles despite being in the dorsal muscle domain and crossing of the anterior segment boundary following contact with the LBD sensory neuron. The SNa shows several phenotypes; failure of either or both of the dorsal and lateral SNa axons to defasciculate from one another, truncation of either or both branches due to an over-fasciculation phenotype and in less than 1% of hemisegments, fasciculation with the ISN. In many hemisegments the mutant motor projection consists of only the two major motor nerves (ISN and SNa) rather than the normal 5 branches, due to a failure of the ISNb, ISNd and SNc branches to defasciculate. The ISNb, ISNd and SNc branches extend into the periphery and are detectable as large clumps of growth cones tightly associated with the ISN or SNa nerve routes.