Riseveinus tenuispinus sp. nov.

(Figs 27–35)

Description. Body length (incl. forewing): ♂, 7.9 mm; Head width (incl. eyes): ♂, 1.5 mm; head length: ♂, 1.6 mm. Crown (Fig. 29) slightly shorter than length of pronotum and scutellum together.

Aedeagal shaft short, swollen at base then gradually narrowing towards apex in lateral view (Fig. 34), with pair of apical processes (Fig. 33); apodeme bilobed with moderately long dorsolateral extensions (Figs 33, 34); paired ventrolateral processes slightly shorter than aedeagal shaft, slender, and recurved dorsally and closely paralleling ventral margin of aedeagal shaft in lateral view (Fig. 34).

Type material. Holotype ♂ (NMNS), TAIWAN: Kaohsiung, Shanping Forest Res., Aiyong Rd. ca. km 8, 1200m, 22°57'32"N 120°41'43"E, 24.vi.2004, C.H. Dietrich, 26-1, sweeping.

Etymology. The specific epithet, a combination of “tenuis” meaning slender, and “ spina ” meaning spinelike, refers to the slender, spiniform aedeagal ventrolateral processes.

Remarks. This species is similar to R. compressus Zhang, Zhang & Wei externally, but differs in having: 1) the aedeagus ventrolateral process slender and gracile (Fig. 33; stout in R. compressus); 2) aedeagus ventrolateral process recurved dorsally and paralleling ventral margin of aedeagal shaft in lateral view (Fig. 34; recurved but well separated from shaft in R. compressus); 3) distal part of aedeagal shaft inflated in caudal view (Fig. 33; parallel-sided from base to apex in R. compressus); 4) aedeagus ventrolateral process close to aedeagal shaft in caudoventral view (Fig. 33; well separated from shaft in R. compressus).