A revision of western Palaearctic oxytorine genera. Part IV, Genus Megastylus (Hymenoptera, Ichneumonidae)

A key to the Palaearctic species of Megastylus Schioedte, (1839), is given. Three new species are proposed: Megastylus suecicus sp.n. female (Subgenus Megastylus Schioedte, (1839)), Megastylus elegans sp.n. female (subgenus Dicolus Foerster, (1869)) and Megastylus tenellus so.n. female (Sub-genus Dicolus Foerster, (1869)). The species Myriarthrus rufipleuris Foerster, 1871, and Megastylus pumilio Foerster, 1871, are taken to be the same as Mesoleptus albocollaris Cresson, 1868 = Megstylus orbitator Schioedte (1839). Megastylus subtiliventris (Foerster, 1871) is a synonym of Megastylus pectoralis (Foerster, 1871). The paper is illustated by 6 text-figures.