Oresbius cushmani, Watanabe, 2025

Oresbius cushmani nom. nov.

[SJN: Matsunokurohosi-habachi-togari-himebachi]

( Figs. 43A–G, 76F, 79L)

Pezoporus opaca Cushman, 1937: 33 .

Aptesis? opaca View in CoL : Townes et al., 1965: 165.

Materials examined. JAPAN: [Honshu] NSMT, 4F, Shizuoka Pref., Nagaizumi , 25. III. 1937 (cocoon of Diprion nipponicus coll.) , IV. 1937 (em.) ; NSMT, 1F, ditto, no collecting data; KPM-NK 81199 , F, Nagano Pref., Ueda City, Takeishi-toge to Utsukushigahara-road , 25. IX. 2011, M. Takakuwa leg. ; KPM-NK 81200 , F, Gunma Pref., Tsumagoi Vil., Kanbara, Takamine-kogen , 3. IX. 2015, K. Watanabe leg.

Description. Female (n = 7). Body polished; covered with setae; body length 8.0– 9.3 mm.

Head 0.55 × as long as wide in dorsal view. Clypeus 2.0–2.1 × as wide as long; weakly convex in lateral view; sparsely punctate; ISP partly coriaceous; with transverse convexity; lower margin truncate in frontal view, sharp in lateral view ( Fig. 76F). Face 0.4 × as long as minimum width; weakly convex medially; matt; densely punctate except for lateral sides. Frons weakly concave above antennal sockets; matt and punctate except for concavities smooth. POL 1.6–1.7 × as OD. OOL 1.0–1.3 × as OD. Gena and occiput densely punctate. Dorsal profile of gena rounded in dorsal view; width gradually narrowing posteriorly ( Fig. 43D). Occipital carina complete. Malar space 1.45–1.55 × as long as basal width of mandible. Mandible weakly convex at base; lower tooth equal in length of upper tooth. Antenna with 30–34 flagellomeres; not flattened and tapped. FL I 2.9–3.5 × as long as maximum depth in lateral view, 1.15 × as long as FL II.

Mesosoma reticulate rugose ( Fig. 43E). Epomia absent. Mesoscutum densely punctate. Notaulus short and weak. Scutellum sparsely punctate anteriorly, densely punctate posteriorly. Mesopleuron with smooth area around speculum ( Fig. 43E). Epicnemial carina present laterally and ventrally. Sternaulus shallow in entire length of mesopleuron. Metapleuron with largely indistinct juxtacoxal carina. Propodeum with short dorsal face, ca. 0.4 × as long as area postero; anterior transverse carina partly present, weakly defined by rugae; posterior transverse carina complete; lateromedian longitudinal carina largely indistinct ( Fig. 43G); lateral longitudinal carina complete; pleural carina complete; area superomedia indistinct; apophysis weak and small; spiracle oval. Fore wing length 7.1–8.2 mm. Areolet as long as maximum width; width steeply narrowing anteriorly; received vein 2m-cu slightly basal than middle ( Fig. 43F). Fore wing vein 1cu-a slightly antefurcal to or interstitial to vein M&RS ( Fig. 43F). Nervellus subvertical; intercepted posterior to middle. Hind femur reticulate coriaceous; 5.0–5.6 × as long as maximum depth in lateral view. Tarsal claws simple.

Metasoma matt. T I 1.95–2.1 × as long as maximum width; apico-median area flat or slightly concave; lateromedian carina present except for apical part; dorso-lateral carina complete. T II 0.6–0.65 × as long as maximum width; sparsely punctate posteriorly. Thyridium present; close to anterior margin of T II; not depressed; ca. 2.0 × as wide as length. T III and T IV finely and densely punctate posteriorly. Ovipositor sheath 0.5 × as long as hind tibia, 0.8–0.9 × as long as T I. Ovipositor straight; apex sharp; apex of lower valve with teeth ( Fig. 79L).

Colouration ( Figs. 43A–G). Body (excluding wings) black to blackish-brown. Setae silver. Subapical part of mandible, lower margin of clypeus, and labrum weakly tinged with reddish-brown. Frontal orbits sometimes with pair of dark reddish-brown markings. FL V to FL X with white markings. Apical parts of trochanters and trochantelli and base of femora narrowly tinged with reddish-brown. Posterior margin of T II narrowly tinged with reddish-brown. T VII with ivory marking medially. Thyridium and ovipositor reddish-brown. Wings hyaline. Veins and pterostigma blackish-brown except for brown wing base.

Male. Unknown.

Distribution. Japan (Honshu).

Etymology. The specific name is from Dr. Robert Asa Cushman (1880–1957), who is a taxonomist of Ichneumonidae in USA and described this species firstly.

Bionomics. Host: Diprion nipponicus Rohwer, 1910 ( Hymenoptera , Diprionidae ) ( Cushman, 1937).

Remarks. This species can be easily distinguished from other Japanese species, O. leucopsis , by the completely black legs (coxae and hind femur except for apex red in O. leucopsis ).