The lethal period is during the late pupal phase.

Lethal at the time of puparium formation. The third larval instar period is extended by up to 4 days. The mature larvae appear slightly bloated. The wing imaginal discs are clumped, enlarged and incapable of differentiation. They form benign neoplasms when transplanted. The remaining imaginal discs develop normally initially, but in older larvae they have a highly abnormal folding pattern and mode of growth; imaginal disc cells invade the epithelia of adjacent discs and also invade the central nervous system, where they destroy large regions of the neuropile and cortex. The large polytene, ecdysone-secreting cells of the ring glands are degenerated.

late pupal lethal