TL;DR: Five genera and 10 species of Sarginae are now recognized from Australia, and a new Australian record is presented for Ptecticus longipes, also known from New Guinea and the Solomon Islands.
Abstract: A taxonomic treatment to genera is provided for the Australian members of the soldier fly subfamily Sarginae. This includes an updated identification key for the Australian genera, along with the diagnosis and illustration of Ptecticus Loew, 1855 and Sargus Fabricius, 1798, and three newly recorded genera: Cephalochrysa Kertész, 1912 (Cephalochrysa gselli (Hill, 1919) comb. nov.), Formosargus James, 1939 and Microchrysa Loew, 1855. Two new species are also described: Formosargus melanogrammus Lessard & Woodley, sp. nov. and Microchrysa wrightae Lessard & Woodley, sp. nov. A new Australian record is presented for Ptecticus longipes (Walker, 1861), also known from New Guinea and the Solomon Islands, and a taxonomic change is made for Formosargus lineata (de Meijere, 1913) comb. nov., from New Guinea, transferred from its previous position within Chrysochlora Latreille, 1829. Five genera and 10 species of Sarginae are now recognized from Australia.
TL;DR: Microchrysa flaviventris (Wiedemann), a species widespread in the Old World, is reported from North America for the first time and apparently is established in the eastern United States.
Abstract: Microchrysa flaviventris (Wiedemann) (Diptera: Stratiomyidae: Sarginae), a species widespread in the Old World, is reported from North America for the first time. Apparently it is established in the eastern United States. Specimens were taken in Alexandria, Virginia in August 2007.