Opius variabilis Provancher, 1888:382, Muesebeck, 1926Muesebeck, C.F.W. 1926. A revision of the parasitic wasps of the genus Microbracon occuring in America north of Mexcio. Proceedings of the United States National Museum 67 (art. 8):1-85.:69, Type (Museum of Public Instruction, Parliament Building, Quebec, Canada). - As Bracon variabilis: - Krombein et al., 1979Krombein, K.V., P.D. Hurd, D.R. Smith & B.D. Burks 1979. Catalog of Hymenoptera in America North of Mexico. Volume 1. Symphyta and Apocrita (Parasitica). Smithsonian Institution Press, Washington D.C. 1-1198. (distribution). - As Microbracon variabilis:
Bracon tortricicola Ashmead, 1888:621, ♀. Holotype ♀, Kirkwood, Missouri, April 28, 1885 (U. S. National Museum, leg. Mary E. Murtfeldt); Muesebeck, 1926Muesebeck, C.F.W. 1926. A revision of the parasitic wasps of the genus Microbracon occuring in America north of Mexcio. Proceedings of the United States National Museum 67 (art. 8):1-85.:69, Type (U.S.N.M., No. 2915). - Dalla Torre, 1898Dalla Torre, C.G. 1898. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. - IV: Braconidae. Sumptibus Guilelmi Engelmann, VIII + 323. (distribution); Muesebeck, 1926Muesebeck, C.F.W. 1926. A revision of the parasitic wasps of the genus Microbracon occuring in America north of Mexcio. Proceedings of the United States National Museum 67 (art. 8):1-85.:69 ( listed as synonym of Microbracon variabilis (Provancher, 1888)).