Vespa velutina subsp. nigrithorax du Buysson 1905

Vespa velutina nigrithorax du Buysson, 1905 Description. Head (Fig. 9): CW / MW = 1.64–1.76 (n = 1.68). Cranium with moderate, irregular rugo-reticulation, except for some parallel rugae between the temporal band and the mid-cranial sulcus. Antenna positioned near the level of the dorsal margin of the clypeus (Fig. 9 D, E), measuring 0.08–0.1 mm in diameter (Fig. 9 E), with very weak pigmentation and a hyaline antennal socket (Fig. 9 D). Temporal band (Fig. 9 D, E) similar to that in V. simillima (Fig. 8 J), with variation in width; edges mostly weakly margined; inner part with moderate ferruginous pigmentation in the dorsal and ventral areas or mostly transparent; ventral edge positioned above the dorsal margin of the antenna. Paired suprafrontal marks relatively weak; dotted patches on the upper frontal area distinct and extending ventrad (Fig. 9 D, E: arrow); region around the frontal suture with 18–23 setae, primarily in the dorsal area; frons, except for this region, with fewer than 14 setae distributed between the dfm and the clypeus. Clypeus (Fig. 9 D, E) with a width similar to or less than the minimum distance between the antennae; dorsal margin of the main disc roundly convex; lateral margin slightly curved, without pigmented spots, except in the tentorial pit; ventral margin shallowly convex; main disc not very high, with a CLI of 1.5–2; main disc with 40–50 setae (sometimes lower than 60 setae); ventral section strongly transverse, with a straight anterior margin. Labrum (Fig. 9 F, left) bearing numerous sensory bristles, except in the zone along the dorsal margin. Palate (Fig. 8 B, C, F: right) with a small median patch (0.03 × 0.03 mm); sclerotized patch relatively poorly developed and pale in color, not extending to the dorsolateral part; conical papillae tiny and densely arranged ventrally; with fewer than 10 papillae present on the sclerotized patch; spicules distributed in the medioventral part, along the lateral margin of the palate, and on the conical papillae (Fig. 9 C, F). Mandible (Fig. 9 D, E, G) strongly sclerotized in the apical two-fifths; outer surface without pits but with a few bumps (Fig. 9 A) or extensively smooth. All mandibular teeth smooth and moderately produced (Fig. 9 G); tooth I similar in size to, or slightly larger and more produced than, tooth II, occasionally bearing small denticles on the dorsal margin; tooth IIIa similar to or more produced than IIIb; teeth I and II separated at an angle of 65 ° – 90 °, II and IIIa at 60 ° – 90 °, and IIIa and IIIb at 75 ° – 105 °; bifurcation point between teeth II and IIIa slightly deeper than the other bifurcation points. Maxilla with approximately 25 setae. Prelabium with approximately 45‒55 setae. Body (thorax and abdomen): Body 21‒23.2 mm in length (n = 50, mean 21.8 mm) and 10–12 mm in width (mean 11.1 mm); integument with setae gradually decreasing in density posteriorly from the fifth integument (often evenly distributed across all segments) with dense spicules. Spiracle shallow; generally uniform in size, except for spiracles 1, 2, and 10, which are slightly smaller; largest spiracle 0.3 mm in diameter; spiracular rim 0.03 mm in thickness with dense spicules of variable sizes. Remarks. Mature larvae exhibit minimal variation within a single colony and consistently retain traits comparable to those of V. simillima simillima. However, distinguishing them from some individuals of V. simillima simillima based solely on morphology is challenging. Specimens examined. South Korea • 30 mature larvae; Jeonllanam-do, Gurye-gun; 35°25'57"N, 127°58'62"E; 10 Sept. 2021; Choi • 10 mature larvae; Gyeonggi-do, Pocheon-si; 37°58'36"N, 127°14'24"E; 13 Oct. 2022; Choi and Ma • 10 mature larvae; Gyeongsangnam-do, Sacheon-si; 35°01'37"N, 128°07'20"E; 19 Oct. 2022; Choi and Ma • 20 mature larvae; Daegu; 35°48'40"N, 128°33'07"E; 7 Sept. 2023; Choi et al. • 5 mature larvae; Gyeongsangbuk-do, Cheongdo-gun; 35°40'37"N, 128°43'19"E; 17 Oct. 2023; Choi and Kim • 5 mature larvae; Chungcheongbuk-do, Boeun-gun; 36°26'28"N, 127°41'35"E; 15 July 2024; Choi • 15 mature larvae; Gyeongsangbuk-do, Gyeongsan-si; 35°49'07"N, 128°43'14"E; 13 Aug. 2024; Ma and Kim • 10 mature larvae; Jeollabuk-do, Muju-gun; 35°52'13"N, 127°39'12"E; 19 Sept. 2024; Ma • 15 mature larvae; Gyeongsangbuk-do, Andong-si; 36°34'05"N, 128°43'33"E; 24 Sept. 2024; Ma and Kim • 15 mature larvae; Gyeongsangbuk-do, Andong-si; 36°33'54"N, 128°43'27"E; 25 Sept. 2024; Ma • 20 mature larvae; Gyeongsangbuk-do, Gyeongsangbuk-do, Andong-si; 36°56'80"N, 128°70'57"E; 02 Sept. 2023; Choi and Kim.