In nomenclature the word homonym is used for identical but independently proposed names for the same or different taxa. For exampe: Ochromyia Lehrer, 2005 is a homonym of Ochromyia Macquart, 1835. As a rule, the junior (more recent) name (in this case Ochromyia Lehrer, 2005) is invalid.
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?