Rhorus Förster, 1869

Kasparyan, D. R., Choi, Jin-Kyung & Lee, Jong-Wook, 2016, New species of Rhorus Förster, 1869 (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from South Korea, Zootaxa 4158 (4), pp. 569-576 : 570

Genus Rhorus Förster, 1869

Type species: Tryphon mesoxanthus Gravenhorst, 1829

The genus can be distinguished from other ctenopelmatine genera by the presence of a characteristic U-shaped emargination between the base of the propodeum and the metanotum as well as by a slender ovipositor in its apical part (these two characters are typical of most Pionini ). Species of Rhorus can be easily recognized by the absence of a suture between the face and the clypeus, by subbasal convexity of the mandible (convexity not strong and usually mat), and by semi-cylindrical, usually yellow ovipositor sheaths (their rounded apices bear a hairy membranous depression dorsally); distinctive characters of the wing venation include the presence in the fore wing of an areolet and nervulus usually very strongly postfurcal in the fore wing and hind wing - presence of a strongly inclivous nervellus usually broken near the lower end. The presence of a slender ovipositor suggests that hosts (sawflies) can be attacked at the stage of early-instar larvae or even eggs; there are records of oviposition through the ocellus in the larval head capsule ( Zinnert, 1969; Pschorn-Walcher and Zinnert, 1971). Adult ichneumon wasps always emerge from cocoons of the host.

All representatives of the subfamily Ctenopelmatinae are koinobiont endoparasitoids and attack sawfly larvae ( Hymenoptera Symphyta ). For Rhorus about 70 sawfly species, mainly belonging to the family Tenthredinidae , are known to be hosts ( Yu et al., 2012).