Megarhyssa atrata (Fabricius)

Pook, Victoria G., Sharkey, Michael J. & Wahl, David B., 2016, Key to the species of Megarhyssa (Hymenoptera, Ichneumonidae, Rhyssinae) in America, north of Mexico, Deutsche Entomologische Zeitschrift 63 (1), pp. 137-148 : 139

Taxon classification Animalia Hymenoptera Ichneumonidae

Megarhyssa atrata (Fabricius) Figs 1, 2

Ichneumon atratus Fabricius, 1781. Species Insectorum, v. 1, p. 436.

Ichneumon tenebrator Thunberg, 1822; 1824. Acad. Imp. des Sci. St. Petersburg, Mem.8: 266; 9: 322. Unnecessarily proposed n. name for atratus Fabricius.

Rhyssa laevigata Brullé, 1846. In Lepeletier, Hist. Nat. Ins. Hym., v. 4, p. 78.

Megarhyssa atrata lineata Porter, 1957. Ent. News 68: 206. Synonymized by Carlson (1979)

Geographic range.

Eastern Nearctic to about longitude 100 °W ( Townes and Townes 1960).

Hosts.

Tremex columba ( Hopkins 1893; Treherne 1916; Beaulne 1939; Townes 1944; Nénon 1995).

Distinguishing characters.

Female: Head and antenna mostly yellow, may or may not have a dark spot above the clypeus. Mesosoma and metasoma black. Mesosoma sometimes with a small yellow spot on posterodorsal corner of pronotum, rarely with yellow markings. Fore wing 15 to 30 mm long; wings infuscate or entirely black. Ovipositor sheath about 3.7 times as long as forewing.

Females may be distinguished from the other species occurring in the USA and Canada by their body color.

Male. Head yellow, may or may not have a dark spot above the clypeus. Mesosoma yellow and blackish brown; metasoma very dark brown to black with a yellow mark on the hind margin of the first tergite; wings hyaline, fore wing 16 to 22 mm long.

Males may be distinguished from Megarhyssa macrurus by the evenly darkened fore wing and the lack of a brown patch at the base of cell 2R1; from Megarhyssa nortoni by the additional yellow markings on the mesopleuron; and from Megarhyssa greenei by the color of the mesosoma.