Heterischnus Wesmael, 1859

Claridge, Brandon, 2021, Revision of Nearctic Heterischnus Wesmael, 1859 (Hymenoptera, Ichneumonidae, Ichneumoninae, Phaeogenini), Journal of Hymenoptera Research 85, pp. 57-79 : 57

Heterischnus Wesmael, 1859

Heterischnus Wesmael, 1859: 83. Type species: Ichneumon pulex Müeller. Monotypic.

Rhexidermus Förster, 1869: 192. Type species: Rhexidermus japonicus Ashmead. Monotypy by inclusion in Ashmead (1906).

Posocentrus Provancher, 1875: 273. Type species: Posocentrus huardi Provancher. Monotypic.

Ischnopsidea Viereck, 1914: 77. Type species: Ichneumon thoracicus Gravenhorst. Monotypic and original designation.

Aethiopischnus Heinrich, 1938: 127. Type species: Aethiopischnus olsoufieffi Heinrich. Monotypic and original designation.

Generic diagnosis.

Among Phaeogenini genera, Heterischnus is easily recognized by a combination of the following: unidentate, falciform mandible; epistomal suture distinct; basal flagellomeres slender and elongate (Fig. 1 ); scutellum moderately narrow, convex, and distinctly elevated above metanotum; areolet (cell 1-2Rs) of the fore wing is closed (Fig. 1 ); hind coxa simple; thyridium wide. In some species, notably Heterischnus huardi (Provancher), the clypeus is medially truncate with acute sublateral projections making such species instantly recognizable as Heterischnus . However, the ventral clypeal margin varies between the aforementioned morphology and being medially straight without acute sublateral projections. The majority of species tend toward the latter condition. Additionally, the tarsal claws of Heterischnus pulex ( Müller) are pectinate which is unique among Phaeogenini , although the tarsal claws are simple in the remaining species.

Figures

Figure 1. Unpublished illustration of Heterischnus huardi (Provancher) lateral habitus and frontal view of head by Professor Masaaki Tokunaga or his assistants, commissioned by Dr. Henry Townes.