Distribution in Iran. Ardabil (Ghahari and Fischer 2011 as Opius magnus), Guilan (Ghahari et al. 2012 b as Opius magnus), West Azarbaijan (Rastegar et al. 2012 as Opius magnus).
Distribution outside Iran. Austria (Fischer 1958 a, 1967 a, 1980, 1981, 1983 a as Opius magnus, 1984, 1997 as Opius magnus; Tobias 1977; Papp 1979 b; Hellrigl 1997 as Opius magnus; Fischer and Koponen 1999; Yu et al. 2012), Finland (Fischer and Koponen 1999 as Opius magnus; Yu et al. 2012), Georgia (Yu et al. 2012), Germany (Fischer 1983 a as Opius magnus, 1984, 1997 as Opius magnus; Papp 1979 b; Fischer and Koponen 1999; Belokobylskij et al. 2003; Yu et al. 2012), Hungary (Fischer 1983 a as Opius magnus, 1984 as Opius magnus, 1997; Papp 1979 b, 1981; Fischer and Koponen 1999; Yu et al. 2012), Italy (Fischer 1980, 1981, 1983 a as Opius magnus, 1984 as Opius magnus, 1997; Monaco 1984; Frey 1989; Fischer and Koponen 1999; Yu et al. 2012), Kazakhstan (Fischer 1983 a; Fischer and Koponen 1999; Yu et al. 2012), Poland (Fischer 1983 a as Opius magnus, 1984, 1997 as Opius magnus; Tobias 1977; Papp 1979 b; Fischer and Koponen 1999; Yu et al. 2012), Russia (Tobias 1977 as Opius sayanicus; Tobias 2000; Fischer 1983 a; Yu et al. 2012), Switzerland (Hoffmeister 1990; van Achterberg 2014 b as Utetes ferrugator), Turkey (Yildirim et al. 2010; Beyarslan and Fischer 2011, 2013 all as Opius magnus), Ukraine (Fischer 1983 a; Fischer and Koponen 1999; Yu et al. 2012).
Host records. Rhagoletis sp. (Diptera: Tephritidae) (Ghahari and Fischer 2011). Yu et al. (2012) reported the following tephritid species (Diptera) as hosts for this species: Anomoia purmunda (Harris, 1780), Carpomya schineri (Loew, 1856), Rhagoletis laternata (Fallen, 1820), R. berberis Curran, 1932, R. cerasi (L., 1758), R. meigenii (Loew, 1844) and Trypeta spp. In Europe, it has been reared from Rhagoletis infesting cherries, Berberis, Rosa and Anomoia purmunda (Harris, 1780) infesting Crataegus (Hoffmeister 1992; Yu et al. 2012).