Some concepts of the interaction of Trypanosoma (Nannomonas) congolense and Glossina pallidipes.

Light and electron microscope investigations were carried out on the infection with Trypanosoma (Nannomonas) congolense of laboratory-reared tsetse flies Glossina pallidipes. Trypanosomes became entombed in the peritrophic membrane (PM) to form intraperitrophic cavities which were more electron-translucent than the amorphous layer of the PM. A hypothesis is suggested that after migration anteriorly in the ectoperitrophic space, the trypanosomes become enmeshed in the PM during its formation in the proventriculus, and that the trypanosomes are extricated in the midgut as the PM advances towards the posterior end of the gut.