The Ameniinae comprise seven genera, of which six occur in Australia; the largest, Amenia, is restricted to this country. Previous studies left some uncertainty about the status of several taxa in Amenia, and Part 1 of this study applies morphometric methods to the problem. These analyses show that Amenia longicornis comprises two geographically isolated, morphologically distinct forms. One occurs around the head of Spencer's Gulf in South Australia and north as far as Alice Springs; the other is widespread across the Nullarbor Plain. Similar studies of A. i. imperialis and close relatives show that A. i. imperialis and A. i. dubitalis are clearly separable by head shape; also, that two other 'forms' of A. imperialis can be distinguished: one occurring in northwestern Australia and arid areas of New South Wales and Queensland, the other in the vicinity of Cooktown, Queensland. Likewise, the two subspecies of A. leonina, A. l. leonina and A. l. albomaculata are morphometrically separable, but with some sign of intergradation, as well as the existence of distinct 'forms' of A. l. albomaculata in the New England area of New South Wales and on the Eyre Peninsula, South Australia. Finally, A. chrysame is shown to comprise two morphometrically separable 'forms', occurring north and south of the 26th parallel. In Part 2, the subfamily Ameniinae is reviewed, with descriptions of eight new species: two in Stilbomyella, four in Paraplatytropesa, and two in Amenia. The last represent morphometrically recognised siblings of A. imperialis. Also, the subspecies of A. imperialis are raised to full specific rank, as are those of A. leonina; genus Formosiomima is relegated to synonymy under Amenia; the New Guinean Platytropesa simulans is newly recorded from north Queensland; and the known ranges of several other species are extended with new records. In Part 3, phenetic studies are offered to support the existing classification within the subfamily, and its zoogeography and possible evolutionary history are discussed. It seems not unlikely that the Australasian taxa stem from a Paramenia-like ancestor, that originated in western New Guinea as sister to the mainly Oriental Catapicephala. One or more of its descendant species then entered Australia from the north, dispersing, with further concurrent speciation, in a clockwise fashion around the continent.