This paper contains a complete catalogue of references to the Australian species of Pelecorhynchus, the description of a new species and a key to those described. Thoracic markings are illustrated from such type specimens as are available for study. Over one hundred specimens have been examined, representing all the known species, four of which, P. distinctus, Taylor, P. tillyardi, Taylor, P. claripennis, Ricardo, and P. deuqueti, sp. nov., are only known from the female. Pelecorhynchus personatus, Walker (= P. maculipennis. Macquart), seems to have been unrecognised in Australian collections and confused with P. nigripennis, Ricardo, from which it is distinguished by doubtful characters. Future investigation will probably show these to be variations of the same species.