Rhagonycha falcata Y. Yang, Liu & X. Yang 2024, sp. nov.

Rhagonycha (s.str.) falcata Y. Yang, Liu & X. Yang, sp. nov. (Figs 15C‒D, 16D‒F, 17B, 18B, 39) Type material. HOLOTYPE: ♂ (CAS), CHINA, Yunnan: Tengchong, Jietou, Datang, 25.74556° N, 98.69630° E, 2030 m, 15.Ⅴ.2006, leg. H.B. Liang. PARATYPES: CHINA, Yunnan: 1♂, 2♀♀ (CAS), Tengchong, Houqiao, Danzha, Zhaobitang, 25.55627° N, 98.20941° E, 29.Ⅴ.2006, leg. H.B. Liang; 1♂ (MHBU), Malipo, Ganbazi, 7.VI.2015, leg. L.M. Li. Differential diagnosis. It looks similar to Rh. spinosa in the appearance, but can be easily distinguished from the latter by the characteristic aedeagus: ventral process of each paramere processively thinned near apex, while expanded in Rh. spinosa (Fig. 5D); conjoint dorsal plate of parameres with lateral margins each with a falcate prominence, and apical margin deeply emarginate in middle, while lateral margins without any prominence, apical margin hardly emarginate in Rh. spinosa (Fig. 5E). Description. Body length: 7.0‒ 8.5 mm (7.0 mm in holotype); width: 1.8‒2.2 mm (1.8 mm in holotype). Male (Fig. 15C). Coloration. Body black except for the following parts: head and pronotum uniformly yellowish orange, elytra pale yellow, almost transparent and feebly darkened at apices. Surface sparsely and finely yellow pubescent, anterior margin of clypeus fringed with pale bristles. Head rounded, surface densely and finely punctate; eyes moderately protruding, head width across eyes about as wide as anterior margin of pronotum; terminal maxillary palpomeres subtriangular, widest at apical third; antennae extending to elytral apices when reclined, antennomeres II shortest, about 2.8 times as long as wide at apices, III about 1.9 times longer than II, VII longest, XI feebly longer than X and pointed at apices. Pronotum subquadrate, about 0.9 times as long as wide, anterior margin rounded, anterior angles subrounded, lateral margins feebly diverging posteriorly, posterior margin nearly straight, posterior angles sub-rectangular, disc strongly convex on posterolateral parts, surface finely and sparsely punctate. Elytra nearly parallel-sided, about 3.3 times as long as humeral width, 4.6 times longer than pronotum, surface finely rugulose-lacunose, almost lustrous at basal parts. Aedeagus strongly swollen laterally near middle (Fig. 16D, E); ventral processes of parameres abrutly thinned apically near bases, with apices narrowly rounded and strongly bent to each other in ventral view (Fig. 16D), progressively narrowed apically and almost straight in lateral view (Fig. 16D); conjoint dorsal plate of parameres obviously longer than ventral processes (Fig. 16D, F), with apical margin roundly and deeply emarginate in middle, lateral margins distinctly diverging apically in dorsal view (Fig. 16E), latero-apical angles acute, inclined ventrally in lateral view, each side with a falcate prominence in middle of lateral margin (Fig. 16E, F); emargination between conjoint dorsal plate and ventral process about 2/5 length of aedeagus (Fig. 16F). Female (Fig. 15D). Similar to male, but with larger and stouter body, eyes less protruding, head width across eyes about as wide as anterior margin of pronotum, antennae thinner and shorter, extending to apical third length of elytra when reclined, pronotum wider and about 1.2 times as wide as long, disc feebly convex on posterolateral parts, elytra about 3.1 times as long as humeral width. Internal organ of reproductive system (Fig. 17B): vagina stout and abruptly thinned at ventroapical portion into a long and thin tube, where diverticulum and spermathecal duct arising separately; diverticulum long and spiral, almost evenly thin along the whole length; spermathecal duct very short and about 1/8 length of apical tube of vagina; spermatheca provided with a spiral tube, progressively thinned apically and nearly as long as diverticulum; accessory gland extremely long, almost three times as long as spermatheca. Abdominal sternite VIII (Fig. 18B) moderately narrowed posteriorly, widely triangular at latero-apical angles, and widely and trapezodinally protuberant in middle of posterior margin. Etymology. The specific name is derived from the Latin falcatus (hooked), referring to its conjoint dorsal plate each side with a falcate prominence. Distribution (Fig. 39). China (Yunnan).