Hover-flies of the genus Melanostoma closely related to Melanostoma dubium (Diptera, Syrphidae)

Two new species of the genus Melanostoma Schin., 1860, closely related to M. dubium (Zetterstedt, 1838), are described, and a key to the species of this group is given. Melanostoma clausseni sp. n. and M. tschernovi sp. n. are closely related to M. dubium (Zett.), but differ in the uniformly black abdomen and legs. Melanostoma clausseni sp. n. differs from M. tschernovi sp. n. in the lustrous mesonotum and finely pruinose frons and face (in M. tschernovi, the face, frons, and mesonotum are covered with gray pruinosity). Holotypes of the new species are deposited in the collection of the Siberian Zoological Museum (Novosibirsk). © Pleiades Publishing, Inc., 2009.