Dihelus hylaevorus
Creators: name: Kyohei Watanabe
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ichneumonidae
Dihelus
Dihelus hylaevorus

description: Dihelus hylaevorus (Momoi, 1966)
(Figs. 1I, 2N, 3D, 6A–E)
Caenocryptus hylaevorus Momoi, 1966: 159.
Dihelus niger Gupta & Gupta, 1978: 561. Syn. nov.
Description. The original description of this species and D. niger (Momoi, 1966; Gupta & Gupta, 1983) lacks some important character states. Thus, I redescribe this species below.
Female (n=14). Body length 6.0–10.0 mm, covered with silver setae.
Head 0.65 times as long as wide. Clypeus 0.45–0.5 times as long as wide, punctate. Face 1.7–1.8 times as long as wide, mat, partly punctate, slightly convex medially. Frons slightly concave, sparsely punctate except for smooth area above antennal sockets, sometimes covered with weak rugae below anterior ocellus (Figs. 6D–F). Occipital carina complete, its lower end joined with hypostomal carina. Lower tooth of mandible 1.5 times as long as upper tooth. MSL 0.6–0.8 times as long as BWM. OOL 1.6–2.0 times as long as OD. POL 1.0–1.3 times as long as OD. Antenna with 22–24 flagellomeres. F1 1.0–1.05 times as long as F2.
Mesosoma polished. Epomia present. Lateral area of pronotum punctate, with striation posteriorly. Notauli distinct and deep on anterior 0.66 of mesoscutum. Scutellum weakly convex. Epicnemial carina distinct, its dorsal end close to subalar prominence. Mesopleuron with striae along epicnemial carina, subalar prominence and speculum. Metapleuron punctate, partly covered with somewhat transversely arranged rugae. Propodeum with anterior transverse carina, posterior transverse carina, pleural carina and basal section of lateromedian longitudinal carina. Area anterior to anterior transverse carina punctate. Other area of propodeum covered with irregular rugae. Propodeal apophysis apparently absent. Propodeal spiracle round. Fore wing length 5.0–8.0 mm. Areolet medium-sized, hexagonal, with sides convergent anteriorly (Fig. 1I). Nervulus opposite to basal vein. Nervellus intercepted anterior to midpoint. Fore tibia with a bulge except for basal 0.25. Hind femur 5.5–5.7 times as long as maximum depth in lateral view. Hind TS2: TS1, TS3, TS4 and TS5 = 2.0: 4.5–4.8, 1.2, 0.5–0.6 and 1.2.
Metasoma mat. T1 2.5–2.8 (2.1 in a single case) times as long as maximum width, without a pair of small triangular teeth at base. Median dorsal carina of T1 absent. Dorsolateral carina of T1 complete or partly narrowly indistinct. T2 0.9–0.95 times as long as maximum width. In lateral view, posterior margin of T8 truncate, its dorsal corner almost right angle (Fig. 2N). Ovipositor sheath 1.2–1.25 times as long as hind tibia. Apex of ovipositor as Fig. 3D.
Coloration (Figs. 6A–F). Body (excluding wings and legs) black, except for: clypeus sometimes tinged with reddish brown; mandible tinged with reddish brown medially; palpi blackish brown; F6–F9 (sometimes also F10) with a white band; facial orbit and ventral part of frontal orbit sometimes tinged with reddish brown; dorsal part of frontal orbit and vertical orbit white; median part of collar tinged with yellowish brown; antenna without a white band; scutellum, postscutellum, posterior part of tegula and subalar prominence with a yellow to whitish yellow spot; posterior margin of T1–T7 narrowly white to reddish yellow; posterior part of T8 and carci white to whitish yellow; ovipositor reddish brown. Wings hyaline; veins and pterostigma blackish brown to brown except for yellow wing base. Legs black to blackish brown, except for: fore and mid coxae sometimes with a small yellow area; tibial spurs yellowish brown.
Male (n=10). Similar to female except for coloration of body (excluding wings) and legs. Body sculpture weaker than female. Face 1.6–1.7 times as long as wide. OOL 1.5–1.8 times as long as OD. F1 1.1–1.15 times as long as F2. F13–F15 (usually also F16) with a tyloid. Fore tibia without a bulge. Hind femur 5.8–6.2 times as long as maximum depth in lateral view. Hind TS2: TS1, TS3, TS4 and TS5 = 2.0: 3.4–3.8, 1.2–1.3, 0.6–0.7 and 0.8–0.9. T1 4.0–4.7 times as long as maximum width. T2 1.95–2.3 times as long as maximum width. Body (excluding wings and legs) black, except for: face, clypeus, all orbits (sometimes except for dorsal end of temporal orbit), malar space, ventral part of scape and pedicel, collar, posterodorsal corner of pronotum, posterior area of propleuron, median spot of mesoscutum (indistinct in a few cases), scutellum, postscutellum, subalar prominence and posteroventral area of mesopleuron yellow; mesosternum, metapleuron, posterior part of propodeum partly tinged with yellow to reddish brown; posterior margin of T1–T7 tinged with reddish brown (Figs. 1G, H). Fore and mid legs whitish yellow to yellowish brown. Hind leg brown to yellowish brown (Fig. 1G). Ventral area of hind coxa, hind trochanter and hind trochanterllus, and hind TS1–TS4 paler than other area of hind leg.
Specimens examined. JAPAN: NIAES, F, Iwate Pref., Mt. Hayachine, 2–8. VIII. 1989, M. Sharkey and H. Makihara leg. (MsT); MNHAH, F, Niigata Pref., Kurokawa, 16. IX. 1960, K. Baba leg.; KPM-NK 69935, F, Niigata Pref., Nagaoka City, Suyoshi Town, Mt. Nokogiriyama, 7. VI. 2014, S. Shimizu leg.; KPM-NK 69936, M, Niigata Pref., Myokou City, Suginosawa, Mt. Sasagamine, 17. VIII. 2013, S. Shimizu leg.; KPM-NK 69937, 69938, 1 F & 1 M, Niigata Pref., Sado Is., Kanaishinpo, Mt. Hakuundai to Mt. Myokenzan, 4. VIII. 2009, K. Watanabe leg.; KPM-NK 69939, F, Tochigi Pref., Kuroiso City, Sugiatado, 2. X. 2000, E. Katayama leg.; KPM-NK 69940-69943, 4 M, Ibaraki Pref., Tsukuba City, Oda, Mt. Hokyosan, 18. V. 2014, S. Shimizu leg.; AEIC, F (holotype of D. niger), Nagano Pref., Kamikochi, 22. VII. 1954, Townes family leg.; KPM-NK 69944, M, Nagano Pref., Outaki Vil., Mt. Ontakesan, 5. VIII. 2010, K. Watanabe leg.; MNHAH, M (paratype of D. hylaevorus), Hyogo Pref., Sasayama, 10. V. 1951, K. Iwata leg.; MNHAH, F (paratype of D. hylaevorus), ditto, 29. V. 1951; MNHAH, F, ditto, 6. V. 1960; MNHAH, F (paratype of D. hylaevorus), Hyogo Pref., Tamba, Ryuzoji, 3. V. 1957, K. Iwata leg.; MNHAH, M (paratype of D. hylaevorus), Hyogo Pref., Sasayama, Okano, 10. VI. 1960, K. Iwata leg.; MNHAH, 2 F & 1 M (paratypes of D. hylaevorus), ditto, 16. VI. 1960; KPM-NK 69945, F, Tottori Pref., Wakasa Town, Mt. Hyonosen, 6. VIII. 2011, K. Watanabe leg.; MNHAH, M, Fukuoka Pref., Mt. Hikosan, 25. V. 1956, S. Momoi leg.
Distribution. Japan (Hokkaido, Rebun Is., Honshu, Sado Is.* and Kyushu).
Remarks. This is the first record of this species from Sado Island. The description about male of D. niger (allotype) is largely differed from male of D. hylaevorus (body black without yellow stripe and punctures). Gupta & Gupta (1978) did not examine the types of D. hylaevorus and did not proposed the description about male of D. hylaevorus. Thus, I think that the male of D. niger may be other species.
description: Published as part of Kyohei Watanabe, 2019, Taxonomic and Zoogeographical Notes of Japanese Cryptinae (Hymenoptera, Ichneumonidae), with Description of Five New Species, pp. 81-113 in Bulletin of the Kanagawa Prefectural Museum (Natural Science) 48 on pages 89-91, DOI: 10.5281/zenodo.11205625