Homozygotes frequently fail to escape from the puparium and die during eclosion. This mortality increases under desiccated conditions and decreases under humid conditions. Homozygous flies are more sensitive to desiccation than wild-type; all flies die within 3 hours under desiccated conditions without a water supply, in contrast to wild-type where 50% survive for more than 15 hours under the same conditions. Flies survive longer in a moist environment conditions without a water supply than in the desiccated environment. There are no significant qualitative differences in the cuticular hydrocarbons of pch⁴ and wild-type flies.