Hemizygous animals show developmental delay throughout all stages. By 9 days after egg deposition (AED) the mutant larvae begin to wander away from food and by 12 days AED some animals form prepupae. The mutant animals cannot complete the transition to the pupal stage, failing to shorten their body, evert spiracles or harden their cuticle. The eye-antennal and wing discs of hemizygous third instar larvae are smaller than wild-type controls at 5.5 days AED and still appear smaller at 9 AED.