Syrphoctonus Förster, 1869

Morishita, Shunsuke & Watanabe, Kyohei, 2025, Review of the genera Homotropus Förster and Syrphoctonus Förster (Hymenoptera, Ichneumonidae, Diplazontinae) from Japan, Zootaxa 5588 (1), pp. 49-76 : 72-73

Genus Syrphoctonus Förster, 1869

Syrphoctonus Förster, 1869: 162 .

Type species: Bassus exsultans Gravenhorst, 1829 . Designated by Viereck (1914).

Diagnosis. According to Klopfstein (2014b), this genus can be distinguished from other genera by the following combination of character states. Face coriaceous and matt; without vertical impressions; entirely black or with yellow central marking in female; entirely yellow in male. Clypeus with thin apical margin; with basal elevation and impressed only laterally; resulting in central area being convex and sides being concave. Antenna with apical flagellomeres longer than wide; with tyloids in male; tyloids linear and narrow and without long setae. Mesoscutum without notaulus; coriaceous and matt with inconspicuous but sometimes dense punctures; yellow shoulder markings usually present. Scutellum only carinate basally. Mesopleuron either entirely coriaceous and matt or rather smooth, especially on upper half; never strongly punctate. Epicnemial carina interrupted behind fore coxa. Propodeum with carinae reduced; at most with some traces of lateral carinae. Propodeal spiracle inconspicuous. Areolet absent; very rarely present as aberration in S. tarsatorius . Hind wing with 2–3 basal hamuli. Hind tibia white, yellow or orange with apex dark. Female metasoma evenly tapered to apex; without transverse impressions. T I without latero-median carina. T II with spiracle dorsal, above lateral fold. T III with spiracle below or behind the fold. Metasoma black; often with yellow apical bands on most tergites ( Fig. 14 B ), or orange on median tergites. Ovipositor sheaths 0.3 × as long as hind tibia; rather stout; laterally compressed; slightly tapered and fully enclosing ovipositor or diagonally truncate; with inconspicuous setae ventrally and apically. T VIII and T IX of males present as separate sclerites. Hypopygium about 2.0 × wider than long, emarginated apically and forming two lobes; outer corners of lobes rounded.

Distribution. Afrotropical, Australasian, Holarctic, Neotropical, and Oriental regions ( Yu et al., 2016).

Remarks. Two species, H. atamiensis and H. tarsatorius , are known in Japan. The former is described based on incomplete descriptions based on damaged holotype. Both species are currently unseparable, and they are likely to be the same species, but taxonomic treatment is reserved.

Figures

FIGURE 14. Syrphoctonus tarsatorius (Panzer, 1809), female―A: lateral habitus; B: mesosoma and metasoma, dorsal view.