Figs. 1–10.

Male. Forewing length 9.6–9.8 mm. General body color dark brown. Distance between ocelli slightly wider than diameter of the ocellus. Head dark brown with brownish M-line; M-line outlined by three dark triangular patches of approximately equal size, the posterior portions of posterior dark areas medially fused with a dark patch covering ocelli, and laterally extended to the compound eye inner margin; the entire dark area appears peach-shaped in outline, with a mesolateral eye-shaped lighter spot near inner margin of each compound eye (Fig. 1); compound eyes black; antennae brownish, scape darker. Pronotum brown with scattered pale markings (Fig. 1); wing membrane brownish, veins dark brown; legs mostly dark brown, but hindleg with wide pale band, nearly two third of total length (Fig. 4). Abdominal segments 1–6 bicolored, terga dark brown but sterna pale, terminalia darker, cerci mostly dark brown, several basal segments yellow brown (Fig. 5).

Male terminalia. Tergum 6 with a tiny median knob at posterior margin. Tergum 7 with posterior margin produced into a trapezoidal to triangular process, covered with distal sensilla basiconica (Figs. 2–3). Tergum 8 with sclerotized anteromedial trapezoidal area, with a few sensilla basiconica (Figs. 2–3). Tergum 9 with two patches of sensilla basiconica and hairs on lateral humps and a small medial patch of sensilla basiconica. Hemitergal processes of tergum 10 sclerotized and elongate, gently curved medially with blunt apex (Figs. 2–3). Aedeagal tube plump, mostly membranous with triangular dorsal sclerite (Figs. 6–7), and a pair of slender lateral projections apically; the projection basally swollen and bulbous, apical third constricted and finger-like, covered with two rows of ca. 4 dorsolateral spines at basal half, apex with an obscure dorsolateral spine (Figs. 6–7), additional 6 scattered spines occur apically in ventral aspect (Fig. 8). Aedeagal sac (Figs. 6 & 9–10) nearly as long as tube, most membranous and bald except 2 dorsal spines at midlength, distal half mostly covered with dorsal spinules before spinous apex, apex slightly curved ventrally and covered with mixed armatures of spines and spinules, dorsally separated by median membrane (Figs. 9–10).

Female. Unknown.

Type material. Holotype male: China, Guangxi Zhuang Autonomous Region, Shangsi County, Shiwandashan National Forest Park, Wangle village near Pearl River, N21°54.316' E107°54.203', 295m, 2013. V.18, light trap, Guoquan Wang Wang (HIST). Paratypes: 2 males (CAUC & HIST), same data as holotype.

Etymology. The species name refers to the bicolored abdominal segments 1–6 of the male that distinguish this species from related taxa.

Distribution. China (Guangxi Zhuang Autonomous Region).

Diagnosis and remarks. The new species shares a similar aedeagal tube with a small subgroup of species in the N. montivaga species group (Zwick 1983) as indicated by Wang et al. (2014), including N. lihuae Li & Murányi, 2014 from Yunnan Province of southwestern China and N. zonata Stark & Sivec, 2008 from Lao Cai Province of northwestern Vietnam and the recently described N. tadpolata Li & Murányi, 2014 known from Guangxi Zhuang Autonomous Region, near the type locality of the new species. Neoperla bicolor appears closely related to N. tadpolata in having a similar color pattern of the head and legs and similar aedeagal structures. However, the male of the new species is characterized by “eye”-shaped head spots and bicolored abdominal segments 1–6 (Figs. 1 & 5). Additionally, both species can be distinguished by the details of the aedeagal armature. In N. tadpolata, the tube bears two groups of 4–5 mesoventral and lateroapical spines, which are absent in N. bicolor. The apex of lateral projection is covered with numerous tiny spines, whereas only one obscure spine occurs in N. bicolor. The apex of the aedeagal sac of N. tadpolata is ventrally curved and hook-like with spinules, but the corresponding area is only gently curved with larger spines dorsally, separated by median membrane in N. bicolor (compare Figs. 6–10 with figs. 5–9 in Wang et al. 2014).