Four sub lethal concentrations 0.5, 1, 2.5, 5% of aqueous extract of Melia azedarach L. were used against the second instars larvae of the housefly, Musca domestica L.. The results of the microscopical preparations and statistical analysis have shown that this aqueous extract had a significant inhibitory effect on the growth and development on the ovaries and ovarian follicles of the adult flies obtained from previously treated larvae with four stage of age, 24, 48, 72, 96 hour after birth. The extract also led decreased in the numbers of ovarian follicles and their degradation. In some instances the microscopically preparations of the mid gut of the housefly have also shown that this aqueous extract has seriously affected the histological structure of the alimentary canal particularly the mid gut. It has led to the separation of the muscular layer from the epithelial lining.