Riseveinus hamatus sp. nov.

(Figs 11–17)

Description. Body length (incl. forewing): ♂, 8.3-8.5 mm. Head width (incl. eyes): 1.5–1.6 mm; head length: 1.5– 1.6 mm. Crown (Fig. 11) about 3/4 length of pronotum and scutellum together.

Anal tube with barblike ventral process (Fig. 14). Aedeagal shaft short, swollen at base and then gradually narrowing towards apex in lateral view, without apical processes; apodeme bilobed, dorsolateral extensions short, rounded; paired ventrolateral processes longer than aedeagal shaft, and close to aedeagal shaft in lateral view (Figs 15, 16).

Type material. Holotype ♂ (NMNS), TAIWAN, Taichung, Dashuishan Forest Rd. km 20, 1250m, 24°15'6"N 120°54'58"E, 18.vi.2004, C.H. Dietrich, 16-1, sweeping . Paratypes: 2♂♂ (NWAFU, INHS), TAIWAN, Taichung, Dashuishan Forest Rd. km 23, 1600m, 24°14'48"N 120°56'8"E 18.vi.2004, J.H. Zahniser, 17-1, sweeping .

Etymology. The specific epithet “ hamata ”, meaning hooked, refers to the barblike ventral process of the anal tube (Fig. 14).

Remarks. This species is very similar to R. sinensis (Jacobi) externally, but differs as follows: 1) anal tube with barblike ventral process (Fig. 14); absent in R. sinensis); 2) in lateral view, aedeagal shaft swollen at base and then narrowing towards apex gradually (aedeagal shaft same width from base to apex in R. sinensis); 3) aedeagal ventral process evenly curved near apex (sinuate near apex in R. sinensis).