The role of the choriothete in tsetse flies

Abstract

The anatomy of the choriothete and its relation to certain features of the tsetse uterus, such as the previously unnoticed radial, uterine ridges, are described. The results of this study suggest that the choriothete is an organ for support of the developing embryo or larva and this role is taken over by the uterine ridges when the larva reaches a sufficient size. The choriothete then appears to degenerate due to stretching of the uterus until the beginning of the next breeding cycle.Hatching takes place with the aid of a labral egg-tooth as in some other dipteran larvae and does not require the additional presence of the choriothete.The uterine ridges also help to form a pool of milk gland secretion around the anterior end of the second-instar larva by locking its body wall to that of the uterus.I am grateful to Dr E. J. Popham and Col. H. W. Mulligan for reading the text and would like to thank Dr T. A. M. Nash of the Tsetse Research Laboratory, Bristol, for the provision of tsetse material. The work was carried out during tenure of a grant from the Ministry of Overseas Development.