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 .