Section of Brachycera. There are two large families in this group, Syrphidae and Phoridae, and a number of smaller ones. They do not possess a ptilinum, and therefore lack the prominent ptilinal suture on the face as in other muscoid (Muscomorpha) flies.
They do still have a puparium with a circular emergence opening, but it is not as precisely ellipsoid in shape as is typical for other muscoids.
Does someone has a scan of Nartshuk E.P. 2003. Key to families of Diptera (Insecta) of the fauna of Russian and adjacent countries. Proceedings of the Zoological Institute Vol. 294: 1-252 for me?