(Figs. 1–3)

Adult habitus (Figs. 1 a–1b). Body color dark brown. Head dark brown; M-line paler; lateral margins and anterior portion of frons brown; tentorial callosities distinct, yellow and oval; palpi and antennae dark brown; the distance between ocelli ca. 1.5X as wide as the diameter of the ocellus; head wider than pronotum. Pronotum trapezoidal, brown, with scattered, darker rugosities; anterior corners sharp while posterior corners rounded. Wings brown and transparent, veins dark brown; legs dark brown except yellow brown basal femora; cerci brown, apex darker.

Male ( Figs. 1–3). Forewing length ca. 13.8 mm. Hindwing length ca. 12.0 mm. The posteromedial area of tergum 6 with several sparse sensilla basiconica. Posterior process of tergum 7 trapezoidal, covered with many sensilla basiconica. Tergum 8 with tongue-shaped upcurved process, with many sensilla basiconica at distal margin. Tergum 9 with two paramedial patches of long hairs, without sensilla patches. Hemitergal processes of tergum 10 sclerotized and finger-like, upcurved medially (Figs. 1c, 2 a–2c). Aedeagal tube plump, with sclerotized dorsal surface and a short hook-like Y-lobe forked near midlength; arm of Y-lobe without apical spines, about as long as stalk (Figs. 2 d–2e, 3a–3d). Aedeagal sac about as long as tube, strongly curved ventrad forming an open loop with a blunt tip, and mostly covered with spines except for ventral surface mostly lacking spines (Figs. 3a, 3 e–3f).

Female. Unknown.

Type Material. Holotype: male (HIST), China: Guangxi Zhuang Autonomous Region, Nanning City, Wuming County, Liangjiang Town, Neichao, Neichao River above Neichao Ming Hotel, 220 m, 23°29.664'N, 108°21.622'E, 2018.V.5, light trap, G.Q. Wang.

Etymology. The name refers to the strongly bent ventral lobes of aedeagus. Latin “curvus” means bent, and “lobus” means lobe.

Distribution. China (Guangxi Zhuang Autonomous Region).

Remarks. The single specimen, the holotype of the new species, is most similar to N. delphina Li, Mo & Wang, 2020 and N. wui Yang & Yang, 1990, in having similar terminalia and the hook-like Y-lobe of aedeagus. The new species may be separated from the two above species by aedeagal sac almost fully covered with distinctly, larger brown spines. In N. delphina, aedeagal sac only has indistinct, fine spinules in the apical half. In N. wui, the aedeagal sac is partially covered by stout spines. In addition, head patterns, apparently differ (figs. 1a, 2a in Li et al. 2020; Fig. 6a, fig. 1 in Yang & Yang, 1990; figs. 4a in Wang et al. 2013b and Figs. 1 a–1b).

The type locality is near the vicinity of the capital city of the Guangxi Zhuang Autonomous Region. This partially mountainous region borders Vietnam and the Gulf of Tonkin. This region is rich in Plecoptera diversity.