Developmental capacities of transplanted genital and anal primordia of Musca domestica and Phormia regina

Abstract

InDrosophila, both sexes develop their whole genital and anal apparatus from one single median genital disc. Larvae ofMusca domestica andPhormia regina are equipped with 3 post-abdominal discs. In females, the median genital disc develops into the external analia, the hind gut and the parovaria. The 2 lateral genital discs together yield the chitinized structures of the 8th abdominal segment and the whole internal genital apparatus except the parovaria and the gonads. When transplanted into larval hosts of the same age as the donors, each lateral genital disc gives rise to an almost complete internal genital apparatus, i.e. they show a regulative capacity without previously being cultured. The entire male genital and anal apparatus develops from the median genital disc. The lateral genital discs of the male, as revealed by transplantation and exstirpation, seem to take part in the development of the syntergite 7+8.