Eulocastra sasakii Sugi 1985

Eulocastra sasakii Sugi, 1985 Eulocastra sasakii Sugi, 1985 - Sugi (1985): 90. Holotype: male, in coll. NHMUK. Eublemma sp.: Sugi (1982): 809. Eulocastra sasakii Sugi: Sugi (1990): 99; Nakamura et al. (1996): 228; Gifu Prefecture (2010): 0005227; Kishida (2011): 206; Fukui Prefecture (2016): 224; Aichi Environmental Research Center (2020): 425; Akita Prefecture Department of Living Environment. Nature Conservation Division (2020): 70; Ministry of the Environment, Japan (2020): 25; Mie Prefecture (2025): 286. Materials Type status: Other material. Occurrence: catalogNumber: INU-12214, CYBG-0244; recordedBy: Y. S. Bae, Y. K. Kim, Y. D. Ju, B. S. Park, H. J. Lee; sex: 1 male, 1 female; lifeStage: adult; occurrenceID: 9047AA3C-789E-51EC-AAFB-C163CC5B673C; Location: higherGeography: Cambodia; Seima; Event: year: 2011; month: 11; day: 09; Record Level: type: PhysicalObject; basisOfRecord: PreservedSpecimen Type status: Other material. Occurrence: catalogNumber: CYBG-0245; recordedBy: (Bae et al.); sex: 1 male; lifeStage: adult; occurrenceID: 3BF14E42-D981-5597-A8AB-E5321A8DABCC; Location: higherGeography: Cambodia; Seima; Event: year: 2011; month: 6; day: 30; Record Level: type: PhysicalObject; basisOfRecord: PreservedSpecimen Description HABITUS (Fig. 1 a, b, c) – Length of fore-wing 6–7 mm in male, 7 mm in female; wingspan 13–15 mm. Antennae filiform in both sexes. Head creamy to metallic dark brownish-grey; ocellus present; labial palpus bright ochre to dark ochre. Thorax creamy to metallic dark brownish-grey, with two very faint greyish bands. Fore-wing ground colour creamy-white; basal area dark grey; sub-basal line black, interrupted, inwardly curved; medial band dark grey, distal half paler than proximal half, with a black discal dot; postmedial line dim, not reaching the subcostal vein; three subterminal patches dark grey, large at the costa, small and indistinct at the tornus; adterminal line grey, diffused, not reaching subterminal area; terminal line black, dotted; cilia grey to dark grey. Hind-wing ground colour creamy-ivory. Wing venation (Fig. 1 d) – Fore-wing with Sc reaching costa near 3 / 4; R 1 free; areole present; R 2 arising from the upper margin of the areole; R 3 and R 4 stalked almost half-length; R 5 arising from the lower margin of the areole; M 1 arising from the upper distal angle of the cell; M 2, M 3 and CuA 1 well separated, M 2 free, arising from near M 3; CuA 2 arising from the lower margin of the cell near 3 / 4; 1 A + 2 A reaching near tornus, 3 A absent. Hind-wing with Sc + R 1 shortly anastomosed with Rs near base; Sc + R 1 reaching near apex; Rs and M 1 shortly stalked; M 2 free, arising from near M 3; M 3 and CuA 1 only shortly stalked; CuA 2 arising from the lower margin of the cell near 2 / 3; 1 A + 2 A reaching near tornus, 3 A absent. Male genitalia (Fig. 2) – Uncus elongated, beak-shaped, apically pointed. Scaphium with a pair of linear sclerites; subscaphium weakly sclerotised. Tegumen moderately sclerotised. Transtilla represented by paired rod-like arms fused dorsally with the diaphragmal membrane; diaphragmal membrane weakly sclerotised, with a granulated field; juxta well-sclerotised, inverted T-shaped. Valva elongated, tongue-shaped, asymmetric, slightly expanded distally; costal margin sclerotised, wavy, with a median protrusion, bearing a cluster of setae; right valva with a well-sclerotised axe-shaped ampullar process connected to the costal protrusion; cucullus broad, blunt in the right valva and rounded in the left valva; inner surface partially membranous, broader in the right valva; distal part of valva weakly sclerotised; harpe broad and flattened, gradually tapering distally to an acute apex. Sacculus stout, weakly sclerotised. Vinculum broadly V-shaped. Aedeagus arched, distal margin partially sclerotised; with a single spear-shaped cornutus. Eighth tergite with a reversed Y-shaped sclerotised plate; eighth sternite with a rectangular marginal sclerotised plate. Female genitalia (Fig. 3) – Papillae anales short. Apophyses anteriores almost as long as apophyses posteriores. Ostium bursae well-sclerotised, subtriangular, laterally folded, twisted at base, with a small asymmetrical curved process. Ductus bursae tubular, posterior 1 / 3 well-sclerotised and twisted, remainder membranous. Cervix bursae elongated, bearing the ductus seminalis, with a weakly sclerotised bulla. Corpus bursae ovate, weakly sclerotised; signum absent. Diagnosis Eulocastra sasakii can be distinguished from other East Asian congeners by the following combination of adult and genitalic characters: fore-wing pattern with a distinct fuscous basal area, a well-defined medial band and three separated subterminal patches; hind-wing uniformly creamy-ivory; male genitalia with asymmetrical valvae bearing a strongly developed ampullar process; and female genitalia with a distinctly twisted ductus bursae and the absence of a signum. It differs from E. shibaharai Kishida, 2010 (Kishida 2010: 61) not only in the fore-wing pattern (presence of a distinct medial band and non-uniformly suffused distal half), but also in the male genitalia, particularly the asymmetrical valva and strongly developed ampullar process (vs. valva symmetrical and processes weakly developed). From E. excisa (Swinhoe, 1885) (Kishida 2011: 206), it differs in the fore-wing pattern, particularly in the presence of a more distinctly defined medial band with a relatively straight inner margin (vs. medial band indistinct or irregular), the subterminal markings separated into distinct patches (vs. forming a broad, continuous dark area) and in the uniformly pale hind-wing (vs. with darker suffusion). From E. neoexcisa Berio, 1954 (Butler 1889: 61; De Prins and De Prins 2026), it differs in having a distinct, undulate postmedial line (vs. faint and irregular), a distinct and continuous subterminal line (vs. interrupted) and, in the male genitalia, a strongly sclerotised distal portion of the valva (vs. weakly sclerotised), a large, triangular ampullar process (vs. relatively small and axe-shaped), an elongate triangular harpe with a blunt apex (vs. broad and flattened, gradually tapering distally) and an aedeagus with a small process on the carina (vs. absent). Distribution Cambodia (Seima), Japan (Aichi, Akita, Fukui, Gifu, Mie) (Sugi 1985, Gifu Prefecture 2010, Kishida 2011, Fukui Prefecture 2016, Aichi Environmental Research Center 2020, Akita Prefecture Department of Living Environment. Nature Conservation Division 2020, Ministry of the Environment, Japan 2020, Mie Prefecture 2025). Taxon discussion Genitalic comparisons with some congeners remain limited, as the female genitalia of E. shibaharai have not been described and the genitalia of E. excisa are insufficiently documented. The ostium bursae and ductus bursae of E. sasakii are naturally twisted, but were partially flattened during slide preparation to clarify their structure. Host plants Molinia japonica (Nakamura et al. 1996, Gifu Prefecture 2010, Aichi Environmental Research Center 2020, Mie Prefecture 2025).