In a recent number of this Bulletin, Lloyd and Johnson (1) attempted to describe and illustrate all the known types of flagellate infections encountered in Glossina. Since this account was written a flagellate, which it is believed has not previously been described, has been encountered in three individuals of G. morsitans at Sherifuri, Northern Nigeria. In the first two cases the worker at the microscope was new to the infections of tsetse and did not notice anything peculiar about the parasite in the proboscides that were being examined. The appearance of the parasites in the stained film caused one slide to be retained with a note, but it was at that time regarded as an aberrant T. vivax infection. In the second instance T. vivax was present, and the unusual forms accompanying it were remarked upon, but unfortunately the slide was not retained. In the third instance it was noticed in the fresh preparation that none of the parasites were fixed to the labrum, as are the vast majority of those in T. vivax infections, nor were they clumped as in this species and in T. congolense. Each individual was free-swimming and many were escaping from the labial cavity, the power of translatory movement being great. The hypo-pharynx was not invaded. The remainder of the fly was then examined and the mid gut was found to be heavily infected, while the salivary glands were negative.