Spilopteron tamdaoensis sp. nov.

(Fig. 6)

Material examined. Holotype: ♂ (OMNH), Vinh Phuc Province, Tam Dao NP, 4.v.1998, 900– 1200 m a.s.l., hand net, R. Matsumoto leg.; paratypes: 1♂ (IEBR) 1♂ (OMNH), same data as holotype; 1♂ (IEBR), same data as holotype except collected on 3.v.1998; 1♂ (OMNH), same data as holotype except collected on 8.v.1998; 4♂ (OMNH), same locality and collector as holotype, 2–3.vi.1997, 500– 1000 m a.s.l.

Description of holotype male. Head. Antenna with 40 flagellomeres, first flagellomere 1.35× length of second; frons concave and polished medially, punctate laterally, carina between antennal sockets extending to face dorsally; face 0.7× as high as wide, with coarse punctures; clypeus about 0.6× as high as wide, subpolished, with sparse punctures median tubercle small; malar space 1.2× as long as basal width of mandible; inner margins of eyes divergent ventrally; diameter of lateral ocellus 0.7× ocellar-ocular distance; vertex with small punctures; occipital carina evenly curved, ventrally meeting hypostomal carina about 1.0× basal mandible width from base of mandible.

Mesosoma. Epomia about 1.1× as long as mandible basal width; pronotum with striations across median groove and dense, small punctures at posterior corner; mesoscutum slightly longer than width at anterior level of tegulae, with dense punctures, pubescent; scutellum densely punctate, pubescent, lateral carina extending to middle; metanotum polished, impunctate; mesopleuron subpolished, impunctate medially, ventrally with dense punctures, pubescent, epicnemial carina extending to subtegular ridge but narrowly interrupted subdorsally; metapleuron subpolished, with dense, small punctures, pubescent, submetapleural carina complete; propodeum with area basalis smooth, longer than wide, area externa with dense, small punctures, pubescent, area superomedia weakly defined, subpolished, area dentipara densely wrinkled, area petiolaris smooth; fore basitarsus 2.9× second tarsomere; mid basitarsus 2.9× second tarsomere; hind leg with femur 4.1× as long as wide, 0.67× length of tibia, tarsus 0.78× tibia, basitarsus 2.1× second tarsomere. Fore wing length 11.7 mm, vein M&RS distad of 1 cu-a, vein 2 rs-m slightly basad of 2 m-cu, hind wing with first abscissa of vein CU 1.2× length of vein cu-a.

Metasoma. Tergites with small punctures, pubescent; first tergite 3.0× as long as posterior width, with dense punctures, lateral longitudinal carina shortly present anteriorly; second tergite 0.45× as long as first tergite, wider than long, slightly longer than third; sclerotized part of first sternite extending to 0.8× length of tergite, to level of spiracle, male subgenital plate pentagonal with anterior margin relatively transverse (fig. 6g) and aedeagus as pictured in figure 6f, with penis valve about 1.3× as long as basal apodeme, basal apodeme with straight tip.

Colour. Reddish yellow with apical flagellomeres black, frons with two black spots and brown markings on mesoscutum and metasomal tergites.

Variation. Paratypes have 37–41 flagellomeres. The area superomedia and area dentipara are completely defined, partly defined or undefined.

Female. Unknown.

Comparison. Spilopteron tamdaonensis sp. nov. is most similar to S. luteum (Uchida, 1930) in general appearance. It differs from the latter by the entirely hyaline wings, the pentagonal male subgenital plate with anterior margin relatively transverse, and its aedeagus with the straight basal apodeme’s tip (which is hexagonal with evenly curved anterior margin and curved basal apodeme’s tip in S. luteum (see Ito & Maeto, 2017)).

Etymology. This species is named after its type locality, Tam Dao National Park, northeastern Vietnam.

Distribution. Currently known from Vinh Phuc Province, Tam Dao NP.