Homozygotes are phenotypically wild type at 18^oC.

Temperature-sensitive period for lethality extends from the second larval instar until twelve hours after pupariation. Shifting adult females to restrictive conditions results in the gradual abolition of oviposition; during the first day normal appearing eggs, many of which hatch, are produced, on the second day the hatchability of the eggs is reduced and by day four the eggs are small and misshapen and lack chorions; oviposition ceases on the fifth or sixth day after shift up; at this time the ovary is deficient in stage 8-11 oocytes and lacks follicle cells indicating a breakdown in vitellogenesis. Shift back down to 25^oC leads to resumption of egg laying after four days. Ovarian response is autonomous in ovarian transplants. Fertility of males irreversibly impaired by shift up to 29^oC.