5. Eustra csikii Jedlička, 1968

Figs 6, 13–15, 30, 37–38.

Jedlička, 1968: 294 (‘ Vietnam: Prov. Ninh-Binh’); Deuve, 2001: 564, 573 (Cuc Phuong Nat. Res. as exact type locality).

MATERIAL. 16♂♂, 7♀♀ (SIEE), Northern Vietnam, Phu Tho Province, ~ 90 km W of Hanoi, Xuan Son National Park, 21º07´01´´N 104º56´39´´E, h= 400–700 m, 6–15.VI.2014, D.Fedorenko leg.; 15♂♂, 7♀♀ (SIEE), same data except 21º06´39´´N 104º57´25´´E, h= 400 m.

REDESCRIPTION. Very similar to the previous species except as follows: BL 2.95–3.35 mm, body (Fig. 6) pale brown, frons, vertex and neck dark brown to black (sometimes frons and vertex reddish-brown), elytra more infuscated due chiefly to ground colour slightly darker, brown, in couple with dark spots larger, almost reaching lateral margin and apex, narrowly separated along suture, and extended to basal 1/4–2/5. Dorsal microsculpture coarse on labrum and neck, superficial on clypeus, hardly traceable to obliterate on frons (except anteriorly), vertex, pronotum and elytra. Elytral aciculate microsculpture entirely or partly within and outside glabrous submarginal area. Head moderately densely pubescent, pronotum sparsely pubescent to nearly glabrous.

Head with neck constriction deep and vertex moderately convex, mostly bicarinate on each side, i.e., with supra-antennal carina and supra-ocular one running close to each other, the former reaching posterior margin of eye or almost so while the latter starting above antennal insertion, declining towards and disappearing on gena. Labrum apically evenly convex.

Pronotum barely longer, PW / PL 1.48–1.61 (1.55, n=5), PW / HW 1.10–1.13 (1.11), PLw / PL 0.21–0.26 (0.24, n=6), PB /PA 0.83–0.90 (0.87), sides mostly subsinuate in front of obtuse basal angles; apex slightly to deeply sinuate. Basal foveae rounded, large and deep, each extended apicad into a submarginal line or not. Explanate lateral margin from narrow and reflexed to wide and little reflexed in the case of shallower or deeper submarginal line, respectively; lateral edge minutely yet distinctly tuberculate or denticulate, more so in basal half.

Elytra shorter, EL / EW 1.32–1.38 (1.36, n=5), EW / PW 1.59–1.69 (1.67). USS consisting of 11-13+5+5 setae.

Legs. Mesotarsomere 1 slightly shorter than mesotarsomeres 2–4 combined and distinctly longer than mesotarsomere 5, TF2 0.92–1.18 (1.06): 1.17–1.27 (1.20); TF3 1.43–1.70 (1.57): 1.32–1.51 (1.38).

Aedeagus (Figs 13–15, 30, 37–38): median lobe with apex toothed; right paramere as long as left one, broadened apically. Internal sac with large apical sclerites.

DIAGNOSIS. The species has very distinctive colour pattern and aedeagus.

DISTRIBUTION. Hitherto known from two localities in Northern Vietnam.

HABITATS AND HABITS. See for the genus.