Homozygotes and hemizygous die as late third instar larvae or shortly after pupariation. Many have large melanotic masses in the larval haemolymph. Mutants have pupal case defects, often being incomplete and uneven - some animals appear to have one half of the animal covered in typical third instar larval cuticle, with the other half covered by a normal appearing, tanned sclerotized puparium. Some mutants never form a puparium. Homozygous mutant germ-line clones have few or no pole cells in 95% of the embryos produced. The epithelial layer beneath the pole cells is disorganised, giving a "pole hole" type phenotype. Mutant embryos also show cytoplasmic clearing defects. Embryos laid by Gdi^L319/Gdi^AK307 mothers show defects in pole cell formation and "pole hole" phenotype. 73% of Gdi^N7-3/Gdi^L319 animals pupate and none survive to adulthood.