Genus Rhembobius Förster, 1869

Rhembobius Förster, 1869: 184 . Type: Phygadeuon quadrispinus Gravenhorst, 1829 . Designated by Ashmead (1900a).

Ulothymus Förster, 1869: 185 . Type: Ichneumon perscrutator Thunberg, 1824 . Designated by Perkins (1962)

Acanthocryptus Thomson, 1873: 520 . Type: Phygadeuon quadrispinus Gravenhorst, 1829 .

Original designation.

Two species, Rh. perscrutator (Thunberg, 1822) and Rh. quadristriatus (Uchida, 1956), have been recorded from Japan. The latter species is recorded by only a male holotype and I could not find the type. In this study, I record the distributional data of the former below. Japanese species can be distinguished by the following key.

Key to Japanese species of the genus Rhembobius (♀ ♁)

(female of Rh. quadristriatus is unknown)

1. Metasoma entirely black (Figs 32A, D), sometimes T II and T III slightly tinged with reddish brown. Legs black (Fig. 32A). Body length 5.0–8.0 mm. ................................ Rh. perscrutator (Thunberg, 1822)

-. Posterior margins of T I, T II, and T III yellowish red. Legs largely yellowish red. Body length 6.5 mm. ................................ Rh. quadristriatus (Uchida, 1956)