Heterischnus bicolorator (Aubert)

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

Heterischnus bicolorator (Aubert)

Figs 2 , 3

Rhexidermis bicolorator Aubert, 1965: 16. Syntype series of 14 specimens [ Musée de Zoologie, Lausanne, Switzerland]. Images of syntype (GBIFCH00759357) examined.

Diagnosis.

Heterischnus bicolorator can be distinguished from other Nearctic Heterischnus species by a combination of the following: 1) flagellum, clypeus, and mesosoma without white markings; 2) coxae black to dark brown; 3) gena rugulose-punctate; and 4) T2-3 brownish-red.

Description.

Female (Fig. 2 ). Body length: 7.7-8.2 mm. Fore wing length: 5.0-5.4 mm.

Color. Head black, except brownish-red mandibular apex. Antenna brown. Mesosoma black. Legs brownish-red with coxae and trochanters varying from black to dark brown, except for brown tarsomere 5. MS1 varying from 0.5 anterior black to dark brown with 0.5 posterior brownish-red, to entirely black; T2 varying from entirely brownish-red, to brownish-red with 0.1 posterior brown; T3 brownish-red with posterior 0.1 brown to dark brown; T4-7 dark brown to black. Wing membrane clear; veins light brown.

Head. Clypeus smooth with dorsal 0.6 punctate with punctures separated by 0.5-1.0 × their diameter becoming less dense apically; apical margin medially concave to nearly straight with blunted sublateral apices. Supraclypeal area rugulose-punctate. Gena rugulose-punctate ventrally, dorsally smooth with coarse punctures 0.5-1.0 × their diameter. Malar space 1.5-1.8 × basal mandibular width. Supraclypeal area rugulose-punctate. Vertex smooth with coarse punctures separated by 0.5-1.0 × their diameter. Antenna with 34 flagellomeres.

Mesosoma. Mesonotum smooth with coarse punctures separated by 0.1-0.5 × their diameter. Scutellum smooth with dense, coarse punctures separated by 0.2-1.0 × their diameter. Mesopleuron varying from densely, coarsely punctate to rugulose-punctate. Speculum coarsely punctate dorsally. Ventral division of metapleuron densely, coarsely punctate to rugulose-punctate. Dorsal division of metapleuron finely punctate. Propodeum rugulose. Propodeal carination complete, except lateral longitudinal carina obsolete anteriorly. Tarsal claws simple.

Metasoma. Postpetiole varying from granulate to rugulose. T2 length 1.4-1.5 × posterior width. T2-7 granulate with dense, shallow, punctation becoming sparser and indistinct posteriorly. Gastrocoelus longitudinally rugulose. Thyridium distant from T2 anterior margin by 2.0-3.0 × thyridial length.

Male. Not examined (not known from Nearctic region).

Material examined.

Non-type material: Canada • 1♀; British Columbia, Stone Mountain Park ; 5500 ft; 20.vii.1973; H. & M. Townes; EMUSENT00000302 • 1♀; same collection data as preceding; 22.viii.1973; H. & M. Townes; EMUS00000151 . USA • 1♀; Alaska, Umiat ; 20.vii.1947; C. Schultz; USNM .

Distribution and biology.

Heterischnus bicolorator is known from western Europe and as far east as Chita Oblast in Russia ( Yu et al. 2016). In the Nearctic, it is known only from two localities in Alaska and British Columbia (Fig. 3 ), but is likely present throughout the intervening areas, including the Yukon Territory. No host information is known.

Comments.

The three Nearctic specimens examined agree with both the original description ( Aubert 1965) and images of a syntype specimen. No significant color or morphological differences could be found that would indicate that the examined Nearctic specimens are not conspecific with Palearctic specimens of H. bicolorator .

Figures

Figure 2. Heterischnus bicolorator (Aubert), female A habitus B mesosoma, lateral view C head, frontal view D head, dorsal view E propodeum, dorsolateral view. Scale bars: 5.0 mm (A); 1.0 mm (B-E).

Figure 3. Nearctic distribution of Heterischnus bicolorator (Aubert).