Male and female genitalia and analia are missing or abnormal in homozygotes. Parasegment 14 is partially transformed into parasegment 13, and there is a rudimentary setal belt in A9 in homozygous embryos.
Hemizygous individuals have abnormal posterior spiracles and a rudimentary ninth ventral setal band.
Complements iab-5 and iab-6 alleles.