The epidermal cells of mature mutant embryos are often misshapen, especially at the basal side, resulting in an aberrant overall organisation of the epidermis and the cuticle often peels off from the underlying epidermis and tracheal cells. Homozygous clones induced in the larval imaginal discs that form the adult body do not affect larval viability, but result in pupal lethality. The pupae stop developing at various time points of metamorphosis, having holes of different sizes in the epidermis. In rare cases, adults with small clones in the abdomen escape lethality and eclose. The small clones in these escapers lack pigmentation. Mutant clones in the head and thorax are never seen in adult escapers. Homozygous clones in the eye disc also lead to pupal lethality.

Homozygous clones in the wing have wing hairs that lack pigmentation and are thinner and flimsier than normal.

In the developing dorsal trunk of the tracheal system of kkv^unspecified mutant embryos, no chitinous cable forms in the the lumen during stage 14, as it does in wild-type. During during stage 15, the lumen of the dorsal trunk fails to expand uniformly, remaining constricted at branch fusions, and the tube becomes excessively overgrown between fusion junctions. This overgrowth continues through stages 15 and 16 resulting in a dilated, elongated and irregularly shaped dorsal trunk. By stage 16, the apical surfaces or the cells lining are irregular, rather than forming the regular 'cobble-stone' array seen in wild-type. However, septate junction formation between these cells appears to be normal and, unlike in mutants where septate junctions are disrupted, trachea are not permeable to 10 kDa dextran dye. The first step in tracheal cuticle production, the deposition of a bilayered envelope, occurs normally, but subsequent deposition of chitin in the procuticle is reduced or absent.

kkv^unspecified mutant embryos have narrower denticle bands than normal and the head skeleton is crumbled. Embryos are sometimes inverted in the egg case.