(Figure 17)
Yezoceryx umaculosus Wang, 1982b: 204. Holotype: ♀, China: Yunnan (IZCAS).
Diagnosis. Yellow with black marks; mesoscutum with U-shaped black mark; scutellum usually with black spot posteriorly; first tergite about 1.4–1.6× as long as its apical width; first sternite with anteriorly projecting hook; ovipositor about 1.8× length of hind tibia.
Material examined. Vinh Phuc, Tam Dao NP: 1♀ (IEBR), 2.vi.1997, 900– 1000 m a.s.l.; 1♂ (OMNH), 7.v.1998, 3♂ (OMNH), 8.v.1998, hand net, R. Matsumoto leg.; Ninh Binh, Cuc Phuong NP: 1♂ (OMNH), 26.iv.1998; 1♀1♂ (OMNH), 27.iv.1998, 200– 300 m a.s.l., hand net, R. Matsumoto leg.; Thua Thien Hue, Phong Dien NR: 5♀ 8♂ (RMNH, IEBR), 15 km W Phong My, 23.iii–6.iv.2001, 80– 210 m a.s.l.; 1♀ 2♂ (RMNH), 12 km W Phong My, 24.iii-6.iv.2001, 60 m; 1♀ (RMNH), 15 km W Phong My, 23.iii–6.iv.2001, 50– 60 m a.s.l.; 1♀ (RMNH), 19 km W Phong My, 23.iii-6.iv.2001, 50- 100m; 1♀ (RMNH), 15 km W Phong My, 23.iii–6.iv. 2001, 150m, Malaise trap, C. v. Achterberg & R. de Vries leg.; Thua Thien-Hue, Nam Dong, Thuong Lo: 1♂ (IEBR), 1-4.ix.2005, Malaise trap, T.Q. Nguyen leg.; Hoa Binh, Xa Linh, Pa Co: 1♂ (IEBR), 23.iv.2002, 1100 m a.s.l., hand net, T.V. Hoang leg.; Bac Can, Ba Be NP: 1♂ (OMNH), 1.v.2006, 20.23 0 N 105.37 0E, 200 m a.s.l., R. Matsumoto leg.
Distribution. Previously known from China (Yunnan Province) (Wang, 1982b), these are the first records of this species from Vietnam.