Black-tie dress code: two new species of the genus Toxomerus (Diptera, Syrphidae)

Toxomerus hauseri Mengual sp. n. and T. picudus Mengual sp. n. are described from Peru and Ecuador respectively. Toxomerus circumcintus (Enderlein, 1938) is treated as a valid species and not considered synonym of T. marginatus, and Toxomerus ovatus (Hull, 1942) is considered junior synonym of Toxomerus nitidus (Schiner, 1868). An identification key for the Toxomerus species with dark abdomens is given along with diagnoses for each studied species