At 25oC, the survival rates of homozygotes are: adult survival - 0%, eclosion - 1%, pupation 4%. At 18oC, the survival rates of homozygotes are: adult survival - 6%, eclosion - 7%, pupation 11%. Ptp69D15 embryos show motor axon defects; 36% of ISNb axons, 6% of ISN axons, 13% of SNa axons and 6% of SNc axons show defects.