Lopaphus sphalerus (Redtenbacher, 1908) (Figs 1–5)

Cercophylla sphalera Redtenbacher, 1908:531; Brock, 1998:59; Candaules caesius Redtenbacher, 1908:539; Hennemann et al., 1998:198; Clark-Sellick, 1998:211; Brock, 1998: 20; Baxter, 2002:11. (Synonymised by Otte and Brock, 2005:187); Lopaphus sphalerus: Hennemann et al., 1998:197; Hennemann, 1999: 19; Seiler et al., 2000:93; Whiting et al., 2003:265; Otte & Brock, 2005:186; Harman, 2012:17; Yamada et al., 2021:269; Brock & Büscher, 2022:535.

Distribution. Vietnam: Than-Moi, China (New record).

Diagnosis. Medium-sized insects, with some species exhibiting fully developed wings. Sexual dimorphism pronounced: female robust, integument rugose with sparse granules laterally flanking the median carina; male more gracile, integument comparatively smoother. Head oval in dorsal view; antennae filiform, distinctly segmented, typically exceeding foreleg length. Female cerci triangular, distally tapering to an acute apex, projecting beyond posterior margin of anal segment. Female subgenital plate with distinct median carina, boat-shaped and strongly keeled, gradually tapering posteriorly; posterior margin narrowly rounded and acuminate, extending conspicuously beyond the posterior margin of anal segment. Legs elongate, lacking spines or denticulations; femora and tibiae unarmed, surfaces smooth and glabrous.

Material examined. 1 ♂, 1 ♀, China, Guangxi, Diding, 810 m, 11.IX.2022, leg. Xiangyi Lu & Qianwen Zhang; 2 ♂♂, 2 ♀♀, China, Guangxi, Diding, 1024 m, 30.VII.2024, leg. Yanting Qin, Zhilu Yu & Bingming Zhu; 2 ♂♂, China, Guangxi, Cenwanglaoshan, 1680 m, 3.VIII.2024, leg. Yanting Qin, Zhilu Yu & Bingming Zhu; 2 ♂♂, China, Guangxi, Leye, 428 m, 9.VIII.2024, leg. Yanting Qin & Zhilu Yu.

Description. Female. Large-sized. Body slender, brown (Fig. 5). Entirely brown, with lighter spots over body (Fig. 2). Head: Small, oval. Longer than wide. Compound eyes large and prominent. Occiput slightly convex. Head capsule with a prominent median carina extending uninterrupted from the frons to the posterior margin of the mesonotum. Antennal socket obvious; antenna filiform, about 70 segments, longer than profemora; scape cylindrical and depressed, pedicel cylindrical, flagellomeres indistinct, covered with setae (Figs 2A–B, 2E). Thorax: Pronotum subrectangular, longer than wide, covered with conspicuous granules, anterior third slightly constricted, the lateral margins gently concave; middle area with distinct transverse sulci extending to the pronotum's lateral margins. Mesonotum roughly trapezoidal, longer than the length of metanotum and median segment combined, with small, regularly aligned spines on both sides of the median carina. Metanotum characterized by a distinctly expanded posterior portion (Fig. 2D). Abdomen: Cylindrical, covered with inconspicuous granules and wrinkles. Median segment rectangular. Lateral margins of tergum II to tergum VI almost parallel, tergum II to V increasing in length; tergum VII– IX decreasing in length, tergum VIII and tergum IX equal in width. Anterior margin of anal segment expanded, posterior margin trapezoidally excavate covered with wrinkles.

Subgenital plate with distinct median carina, boat-shaped and strongly keeled, gradually narrowing to backward, surpassing the posterior margin of anal segment, posterior margin narrow and slightly projecting. Cerci small, triangular, strongly elongated, and dorsoventrally flattened that extends beyond the posterior margin of anal segment (Fig. 1E–G). Legs: Thick. Hindlegs slightly longer than forelegs; midlegs shortest. Profemora distinctly curved basally, with distinct carina; internal margins triangular. All femora and the corresponding tibiae about equal in length. Wings: Tegmina coriaceous, pale yellow with irregular light brown maculae, extending to the midlength of metanotum, apex rounded, venation discernible. Hindwings 5× as long as tegmina, membranous, translucent light gray, at rest folded and extending to posterior margin of tergum III (Figs 1A–D, 2F–G).

Male. Body medium, much smaller and slender than female (Table 1, Fig. 3). Entirely brown, with lighter spots over body (Fig. 3A–C). The last three abdominal tergites black. Head: Oval, longer than wide; occiput distinctly depressed. Compound eyes strongly protuberant. Antennal socket obvious. Antenna filiform, composed of approximately 70 segments. Scape cylindrical, slightly depressed; pedicel cylindrical; flagellomeres each bearing dense setae (Fig. 3G). Thorax: Pronotum trapezoidal, beige, bearing distinct longitudinal and transverse sulci; median transverse sulcus extending to lateral margins. Mesonotum subtrapezoidal, dark green, with a longitudinal carina along midline; white punctations bilaterally arranged along midline. Metanotum posteriorly expanded. Abdomen: Slender, covered with inconspicuous granules and wrinkles. Median segment rectangular. Lateral margins of tergum II to tergum VI subparallel; tergum II to V progressively increasing in length and slenderness; tergum VIII to X progressively enlarging.

Anal segment cleft, densely covered with long setae and minute spinules. Subgenital plate spoon-shaped, extending to the anterior margin of the anal segment. Cerci obvious, shorter than operculum, slightly curved, cylindrical, exceeding the end of anal segment, apices rounded, covered with long setae (Fig. 3D–F). Legs: Similar to female. Femora and tibiae with dense setae, tarsi covered with setae. Wings: Tegmina coriaceous, light brown, extending to the midlength of metanotum, apex rounded, venation clearly discernible. Hindwings elongate, broadly fan-shaped, brown, membranous, extending to tergum III with distinctly radiate venation, semitransparent; folded beneath forewings at rest.

Eggs (Fig. 4). Spherical, dark gray overall (Fig. 4A, C). Capsule black, oval in cross-section. Operculum oval, black, distinctly separated from capitulum by a smooth, black terminal rim. Capitulum oval, dark gray, with short shanks smoothly fused to operculum. Micropylar plate elongate, spoon-shaped, length ≈0.75× egg length, margins sharply defined (black); micropylar cup black, positioned adjacent to posterior end of plate. Surface sculpture: smooth, with slight gloss on terminal rim and capitulum (Fig. 4B).

Remarks. Morphological examination revealed notable similarities between Acrophylla sichuanensis and Lopaphus sphalerus, but they could be distinguished by the following characteristics: in Lopaphus sphalerus, the body size is smaller than that of Acrophylla sichuanensis; ocelli absent; the antennae are longer than the proferomora; and the legs lack spines or teeth. In Acrophylla sichuanensis, the tegmina are elongateovate, extending to the posterior margin of the metanotum, whereas in Lopaphus sphalerus, the tegmina are smaller, teardrop shaped, and reach only the middle of the metanotum.

The cerci of female Acrophylla sichuanensis are elongate, flattened and leaf-like, and female subgenital plate is elongate-navicular, barely reaching the base of the cerci. In contrast, the cerci of female Lopaphus sphalerus are triangular, and the female subgenital plate is boat-shaped and strongly keeled, and the opercular valves are spatulate, which are longer than those of Acrophylla sichuanensis, extending to the middle of the female cerci.