Omegasyrphus

There are five myrmecophilous species in this genus. These are small Microdontinae flies with a distinctive abdominal shape; the second segment is widened, flattened, and flared, with its lateral margin subcircular, thickened, and rounded, and the rest of abdomen (third–fifth segments) narrowed and cylindrical. Larvae are found in ant nests. They are native to southern North America. The genus was previously treated as a subgenus of Microdon.