Type species: Nomia californiensis Michener, 1937 = Nomia tetrazonata Cockerell, 1910, by original designation.
Brief diagnosis. ♂, Scutellum without projections, calcar of intermediate tibiae shorter with fine closely spaced teeth, ♀, External calcar of hind tibiae bears strong subapical tooth inserted at right angles. Basal plate of hind tibiae keeled in form of a shield, centre being hairy.