Ichneumon helvolus Cresson, 1867:312, ♀. 4 ♀♀, Connecticut, Pennsylvania, Illinois; Heinrich, 1977Heinrich, G.H. 1977. Ichneumoninae of Florida and neighboring states (Hymenoptera: Ichneumonidae, subfamily Ichneumoninae). Arthropods of Florida and neighboring land areas 9:1-350.:313, Holotype ♀ (ANS). - Cresson, 1867Cresson, E.T. 1867. A list of Ichneumonidae of North America, with descriptions of new species. Part I. Transactions of the American Entomological Society 1:289-312. (distribution). - As Diadromus helvolus: - Heinrich, 1977Heinrich, G.H. 1977. Ichneumoninae of Florida and neighboring states (Hymenoptera: Ichneumonidae, subfamily Ichneumoninae). Arthropods of Florida and neighboring land areas 9:1-350. (distribution); 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).
Ichneumon Magdalensis Provancher, 1890:248, Heinrich, 1977Heinrich, G.H. 1977. Ichneumoninae of Florida and neighboring states (Hymenoptera: Ichneumonidae, subfamily Ichneumoninae). Arthropods of Florida and neighboring land areas 9:1-350.:313, Holotype ♂ (Provincial Museum Quebec). - Heinrich, 1977Heinrich, G.H. 1977. Ichneumoninae of Florida and neighboring states (Hymenoptera: Ichneumonidae, subfamily Ichneumoninae). Arthropods of Florida and neighboring land areas 9:1-350.:313 ( listed as synonym of Diadromus helvolus (Cresson, 1867)); 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.:487 ( listed as synonym of Diadromus helvolus (Cresson, 1867)).