Heterozygotes die as early pupae at 29oC; leg and wing discs evert, but the cephalic complex fails to evert. The temperature-sensitive period is during the third instar to early pupal stage and persists for approximately 15 hours. Homozygous females express a maternal effect on embryonic viability; only 0-5% of eggs laid by homozygous females at 29oC hatch.
Lethal phase is during the early pupal stage at 29oC.