In kkv^IB22/kkv^63-20 mutants, the cuticular and luminal chitin of the tracheae is absent, and there are dilations and constrictions in the dorsal trunk and apical expansions in other branches. Defects in cuticle formation are also observed.

In cuticle preparations of mature homozygous embryos, the cuticle detaches from the body and dilates (indicating a loss of cuticle integrity), so that the embryos appear wider, but not longer, than wild-type embryos. Ventral denticle belts and dorsal hairs are present, but the denticle belts are stretched laterally, and probably as a consequence, their arrangement appears sloppy compared to wild type. The number and shape of the denticles is normal and they do not collapse, even though they do not contain chitin. The denticles are less pigmented than normal. The aberrant body shape seen in cuticle preparations is not as dramatic in living mature homozygous embryos manually freed from the egg case, although these embryos appear more transparent than wild-type embryos. The tracheae are not visible in these mutant embryos and the presumptive tracheal cells appear collapsed. The cuticle of mature mutant embryos has a variable thickness, due to abnormalities in the epicuticle and procuticle (the cuticle envelope is normal); the lower epicuticle is broadened at the expense of the upper epicuticle and the procuticle consists of a spongy and amorphous material probably composed of free procuticular chitin-binding proteins instead of protein-chitin laminae. There is no adhesion zone at the surface of the epidermal cell, in contrast to wild type. There is more electron-dense material present in the cuticle of mature mutant embryos compared to wild type. At stage 17, the epicuticle is uneven and penetrates the lower amorphous procuticle in mutant embryos, in contrast to wild-type embryos at this stage where the uniform epicuticle lies above the fibrous procuticle. The adhesion zone at the apical plasma membrane of the epidermal cell is missing in mutant stage 17 embryos. The hindgut and its cuticle appears normal in mature mutant embryos and the cuticle does not detach from the gut epithelium.

kkv^IB22/kkv^63-20 has embryonic/larval tracheal section phenotype, non-suppressible by Scer\GAL4^btl.PU/exp^UAS.RB

kkv^IB22/kkv^63-20 has embryonic/larval tracheal section phenotype, non-suppressible by reb^UAS.cMa/Scer\GAL4^btl.PU