Mutant embryos show abnormalities in cells of the peripheral nervous system, including the absence of many neurons, especially in the dorsal and ventral clusters and an abnormal morphology of chordotonal lateral organ neurons, which appear bunched and lack the normal apical dendrites. The v'chn1 and dbp neurons are usually absent. Homozygous clones in the adult notum often fail to generate macrochaetae, with the scutellar bristles being the most sensitive to being lost. The penetrance of this phenotype is not complete. The bristle shaft, but not the tormogen, is seen to be lost at a low frequency. Sensory organ precursor cells are often missing in homozygous clones in the third larval instar wing disc.