The taxonomic status of three of the previously described Armillifer spp. is unequivocal but there is some confusion regarding A. monilijbrmis. By using three diagnostic criteria, namely, hook dimensions, annulus number and the form of the terminal segment, we have shown that A. moniliformis australis from Australasian pythons, previously considered as a race of A. moniliformis by Heymons (1932), is, in fact, a distinct species. These criteria also distinguish another species A. arborealis sp. nov. from Australasian tree snakes. The genus Ligamifer, which embraces the single species Ligamifer mazzai, is shown to be invalid. A reinterpretation of the morphology of the terminal segment firmly places the species within the genus Armillifer. The species is renamed Armillifer mazzai to preserve the nomenclatural homogeneity of the taxon. The latter now comprises seven species. There is a distinct possibility that some of the new species could utilize man as an accidental intermediate host.