1. Diplonevra nudisetalis sp. nov.

(Figs. 1–4)

Descripton. Male. Frons (Fig. 1) dark brown, with 50–60 scattered setulae. Supra-antennal setae below lower interfrontal setae and closed to each other. First row of frontal setae a little convex, lower interfrontal setae further from each other than either is from a lower fronto-orbital seta. Second row straight, all four setae are equidistant. First flagellomere dark brown, oval. Palpus brown and 3 times as long as its breadth, with 6 setae on ventral apex. Proboscis mainly whitish yellow, but darker at tips of labella.

Scutum and scutellum dark brown, with 3 notopleural setae. Scutellum with 4 setae. Legs dark brown, but fore tibia and tarsomeres 1–4 yellow brown, tarsomere 5 dark brown. Fore tibia without isolated setulae at basal half, but with a row of about 10 small spines, which are lightly differentiated from adjacent pubescence. Mid tibia with 2 longitudinal hair palisades, anterodorsal one almost straight and extending to 1/2 (0.58) of tibia. All mid tarsomeres dark brown. Posterior on median area and two groups of microtrichia on basal and dorsal parts respectively. Posterior face of hind femur with 5–6 strong lower setae and 2 strong upper setae arranged longitudinally (Fig. 3). Hind tibia with 2 setal palisades and with 2 anteroventral setae. Wing (Fig. 2) length 2.20–2.25 mm, width 1.07–1.09 mm. Costal index 0.52–0.53. Costal ratios 3.92–3.98:1:1. Costal cilia length 0.06–0.08 mm. Costal sections 2 and 3 swollen; Vein M 1 curved.Alula with 5 setae. All veins brown and membrane yellowish brown. Halter brown.

Abdominal tergites dark brown.Venter dark grayish brown.Male terminalia (Fig.4) dark brown. Left side of epandrium a little triangular, with about 10 long setulae, the longest one at the posteroventral corner. Right side of epandrium broad, with about 10 long setulae toward posterior margin. Hypandrium with pubescence, without setulae. Cerci and proctiger light brown basally and whitish brown apically.

Body length 2.24–2.45 mm.

Female. Unknown.

Distribution. China (Beijing).

Etymology. The specific epithet is derived from Latin words nudus (naked) and setalis (seta), referring to the character of fore tibia.

Specimens examined. Holotype, ♂, Beijing, Huairou, Labagoumen (40°33'36"N, 116°37'36"E), 7-VI-2016, Tao Li; 1 ♂, same data as in holotype.

Remarks. The species is similar to D. nigritarsis Lee et al. 2022, but it differs by only tarsomere 5 of fore leg darker and the upper setae of posterior face of hind femur arranged longitudinally.