Genus Ischnus Gravenhorst, 1829

Ischnus Gravenhorst, 1829a: 638 . Type species: I c h n e u m o n p o r re c t o r i u s Fabricius, 1787 (= Ichneumon inquisitorius Müller, 1776). Designated by Westwood (1840).

Habrocryptus Thomson, 1873: 498 . Type species: I c h n e u m o n p o r re c t o r i u s Fabricius, 1787 (= Ichneumon inquisitorius Müller, 1776). Designated by Viereck (1914).

Aglaocryptus Cameron, 1903b: 31 . Type species: Aglaocryptus curvimaculatus Cameron, 1903 . Designated by Viereck (1914).

Erythrocryptus Cameron, 1905b: 126 . Type species: Erythrocryptus rufus Cameron, 1905 (= Cryptus atricollaris Walsh, 1873). Monobasic.

In Japan, two species, I. homonae (Sonan, 1930) and I. yezoensis (Uchida, 1936), have been recorded. I found a new species from Japan and newly describe this species below.