Eggs laid by mutant females are arrested prior to completion of the first mitotic division, although they are fertilised. The polar bodies in these embryos are abnormal; in some cases the microtubules surrounding the polar body are normal, but the chromosomes within the polar body fail to form the normal rosette shape, while in other cases, both the chromosomes and microtubules are abnormal, more closely resembling mitotic spindles, but lacking spindle asters. Most of the arrested embryos also contain a single mitotic spindle with asters (in wild-type embryos, this is derived from the male and female pronuclei), but some of the chromosomes within the spindle are aberrantly localised to the poles. Anaphase and interphase figures are not seen, indicating arrest at metaphase. Homozygous and ball^Z3-0437/Df(3R)Tl-I oocytes show defects at stage 14; while 50% have normal metaphase I spindles, the other 50% have chromosomes in three distinct foci, suggesting a failure to establish or maintain the metaphase I spindle. The karyosome forms only in the early stage of oogenesis (stage 3) in homozygous oocytes, and does not form at all in ball^Z3-0437/Df(3R)Tl-I oocytes. The follicle cells in homozygous ovaries undergo the transitions from mitosis to endocycles to gene amplification in a manner that is indistinguishable from their sibling controls. Similarly, the transition of nurse cell chromosomes from polyteny to polyploidy is normal.