Double heterozygotes with brrbp-5, br5 or br2Bc-2 show no effect on development. Heterozygous brrbp-5 females and mutant brrbp-5 males homozygous for Eip74EFneo24 pupariate normally. Half of each group die during prepupal development, resembling severe phenotype Eip74EFneo24 mutants. 8% display novel phenotypes. Head eversion fails and rudimentary appendages/cryptocephalic head structures develop. 58% of Eip74EFneo24 mutants carrying a single effective dose of br+ arrest during the prepupal period. 20% of these prepupae show a misshapen puparium. A novel microcephalic phenotype results from partial head eversion, though eyes do develop. Leg and wing structures are absent. Lethal phenotype is more severe than either Eip74EFneo24 or br5 alone. More than 25% of Eip74EFneo24 carrying a single effective dose of br+ formed a misshapen puparium. This phenotype is 100% penetrant in a br2Bc-2 mutant background. Most double mutants die during the prepupal stage, earlier than either br2Bc-2 or Eip74EFneo24 mutants alone. In 16% of double mutants eye development proceeds to the point where pigment can be observed, but other discs do not undergo morphogenesis.