Progenies from the homozygous pleiohomeotic parents showed various abnormal developmental aspects due to maternal effects. They caused embryonic death before larvae hatching, cell death and homeotic transformations. Head was severely disrupted and its involution was abnormal. Unlike other Polycomb group genes, pleiohomeotic mutants showed weak homeotic transformation. Thoracic segments were transformed just to the first abdominal one, which is unique among Polycomb group mutants. Sixth and seventh abdominal segments were transformed to the eighth one. As pleiohomeotic mutants often caused segment defect, it is supposed that pleiohomeotic gene may be involved in segmentation as well as regulation of the homeotic gene expression. These maternal effects were recovered in proportion as the number of paternal pho+ allele increased.