Bees in the family Megachilidae have been collected and described from Australia since the earliest scientific expeditions. However, the only major revision of Australian megachilid bees was concerned with taxa at the level of subgenus and above. This study represents the first comprehensive revision of a megachilid group at species level. It is restricted to the apparently wholly Australian subgenera of ChaiIcodoma Lepeletler sensu Michener.The subgenera Austrochile Michener, Chaiicodomoides Michener, Hackeriapis Cockerell, Rhodomegachlle Michener, Schizomegachlie, Michener and Thaumatosoma (Smith) of ChaiIcodoma are revised. Of the 108 species names previously included in these subgenera, 40 are considered to be synonyms.Morphological characters Important for grouping and separating species are discussed and illustrated. In males, modified sterna 5, 6, and 8, and genitalia are illustrated for all type species of genera and subgenera, the first species in a species group, and for new species unless very similar to those already Illustrated. Sternum 8 is illustrated for almost all species. Scanning electron micrographs for most types of male mandibles are included. Pore tarsi are illustrated for most species with modified fore legs, and, in a few, photographs of the entire leg are provided. In females, scanning electron micrographs of the main mandible types are given, the clypeus Is Illustrated for almost all species. Most species are redescribed. Measurements of overall length, wing length, and relative head measurements are recorded for all species.The genus Thaumatosoma, previously reduced to a subgenus of ChaiIcodoma, is reinstated and redescrlbed, and includes two species. Two new genera, Coorooa with 14 species, and Torridapis with 24 species, are described. The subgenera Hackeriapis and Austrochlle are elevated to generic status, and redescrlbed. Hackeriapis includes 26 species. Austrochile Includes 8 named species, with 32 previously unknown species awaiting description. ...............................