Homozygotes die as late embryos or early first instar larvae. Embryos have no posterior spiracles.

Suppresses penetrance of head defect phenotype when in trans with Abd-B^iab9-tuh-3. Heterozygotes with Abd-B^iab9-tuh-3 exhibit genital defects.

A5-A8 (including female genitalia) transformed to A4 in mosaics. Embryos have sclerotic plates in pA8 and occasional extra denticles in A9, and parasegments 10-13 are transformed to parasegment 9.

Heterozygous males have a 7th tergite, there is loss of pigment in the anterior of the 5th tergite, and the 6th sternite has bristles.

Abd-B^S4/Abd-B^S7 embryos show an extreme Abd-B mutant phenotype: denticle belts of parasegments 10-13 resemble that of parasegment 9. Sense organs of parasegment 14 are missing or abnormal. There is a large bald area posterior to the ventral denticle, juxtaposed by a pair of sclerotised plates, which are often associated with two lateral groups of fine denticles. The dorsal spinule patch is absent. There is a supernumerary area of spinules posterior to the dorsal hairs of parasegment 13.