Polytene chromosome maps of the tsetse fly Glossina austeni have been prepared and a description of all the principal chromosome markers is provided. A detailed comparison has been effected between these chromosomes and the polytene elements of G. m. morsitans the only other member of the same sub-genus so far mapped. Although there are many similarities in banding pattern a relatively large number of paracentric inversions and at least one pericentric inversion separate the two species. There are also groups of bands in both species which are not shared in common.