Females containing homozygous germ line clones efficiently produce eggs for at least 10 days after eclosion. The eggs are approximately 70% the length of wild-type eggs and are abnormally round. Some stem cells are still dividing actively in 4 day old females containing homozygous germ line clones. The morphology of the germarium is often abnormal in these flies, with region 1 being shorter than normal. Embryos derived from females containing homozygous germ line clones crossed to either wild-type or pnut^rN498/+ males die without hatching. The embryos have a characteristic but variable cuticle phenotype. The cuticles are always smaller than wild type and usually do not fill the eggshell. The head and tail structures are severely defective. Denticles can be identified and are usually grouped in clusters or bands, but the number of bands varies in number (from 0 to 5, with an average of about 3), shape, size and position. The types and severities of the cuticle phenotype are similar in embryos derived from crosses of females containing homozygous germ line clones to either wild-type or pnut^rN498/+ males. Actin organisation prior to cellularisation appears approximately normal in embryos derived from females containing homozygous germ line clones. The actin cytoskeleton appears normal at the beginning of cellularisation and through the slow phase of cellularisation. However, defects in the organisation of actin at the bases of forming cells are seen during the fast phase of cellularisation, although most embryos appear grossly normal at this stage. The actin does not resolve into the discrete rings seen in wild-type embryos and is more uniformly distributed in the plane of the leading edge, except for the presence of concentrated "bars" of actin between some pairs of cell bases. Approximately 10% of the embryos show regions where the bases of cells are unevenly closed. In these embryos, there is an associated disruption of the actin cytoskeleton along the lateral surfaces of the forming cells and occasional abnormal displacement of nuclei from the cortex. The bases of many cells appear to reopen at the beginning of gastrulation, the distribution of actin along the cellularization front becomes more patchy than in wild-type embryos, cell integrity is disrupted over large parts of the embryo and germ band extension is delayed. In slightly older embryos, nuclei that are no longer surrounded by an actin cytoskeleton are seen and small areas at the anterior of the embryo seem to be devoid of nuclei. The actin cytoskeleton at the ventral furrow is grossly disorganised.