With tomentum. For example: Dasybasis elquiensis (Tabanidae): 'Tergites I to VI with broad greyish tomentose median posterior spots. Tergites III-VI with pale greyish tomentose sublateral spots.'
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?