Stenus perodiosus nov.sp. (Figs 12, 38, 67)

Type material: Holotype () and 17, 19 - paratypes: Taiwan: Nantou Hsien: Yushan National Park, 1.8 km W Pai-Yun Hut, 3375m, 17.V.1991, A. Smetana (T 85) . Paratypes: 11, 9: ibidem, 2 km W Pai-Yun Hut, 3350m, 16.V.1991, idem (T 84) ; 1, 1: Yushan National Park, Mun-Li Clif, 2700m, 13.V.1991, idem (T 79).- HT and PTT in coll. Smetana (Ottawa), PTT also in cN, cT and in cP .

Description: About as in S. persubtilis nov.sp.

Length: 2.5-3.5mm (forebody: 1.4-1.6mm).

PM of the HT: HW: 29; DE: 15; PW: 21; PL: 21; EW: 26.5; EL: 23; SL: 17.

Male: Metasternum shallowly impressed, moderately coarsely and moderately densely punctate, interstices often as large as half diameter of punctures. Anterior sternites simple, sternite 7 finer and denser punctate and pubescent posteromedially. Sternite 8 with a very shallow apical emargination (LS: ED= 50:2). Sternite 9 with comparatively short apicolateral teeth (fig. 12). Aedeagus (fig. 38), apical portion triangularly narrowed, apex acute, expulsion hooks connected medially; parameres slightly longer than median lobe, with about 8-9 apical setae.

Female: Sternite 8 at posterior margin slightly projecting, apex moderately broadly rounded. Valvifer with a comparatively short apicolateral tooth. Spermatheca (fig. 67), infundibulum more than 3x as long as broad.

About as S. persubtilis, but the elytra with deep longitudinal impressions in lateral half and near suture; median portion of frons distinctly exceeding the level of medial eye margins; longitudinal impression of pronotum deep, broadly impunctate and deeply reticulate, dull; abdominal punctation throughout very dense.

Comparative note: This new species resembles many similar species with deep elytral impressions, from which it should be distinguished by examining the sexual characters.

Etymology: Because of its great similarity with other species of the group and the difficulty to identify this species I name it " perodiosus " (Lat.= very odious).