Fig. 1. Defective differentiation of mmy mutant cuticles. (A-G) Light microscopy of wild-type and mmy mutant larvae. (A) The wild-type larva has a colourless cuticle with tanned ventral denticles and head skeleton that is visible through the vitelline membrane. In larvae homozygous for mmy^IK63 (B) or for the P-element insertion KG08617 (C), no ventral denticles, head skeleton or cuticle are visible, and transheterozygous mmy^IK63/Df(2L)BSC6 larvae (D) display similar cuticle defects to homozygous mmy^IK63 mutant larvae. In all these mutant genotypes, the salivary glands accumulate abnormal debris (arrows in B-D). (E-H) Removal of the vitelline membrane reveals that larvae mutant for mmy^IL07 (F) have a distended cuticle compared with the wild type (E). Moreover, the mmy^IL07 mutant head skeleton (H) is darker and appears discontinuous compared with the wild type (G).