Helius (Helius) pallidissimoides Xu, Ma & Zhang 2024, sp. nov.

Helius (Helius) pallidissimoides Xu, Ma & Zhang, sp. nov. (Figs 4–5) Diagnosis. Antenna with flagellomeres oval, apically tapering and elongated. Rostrum nearly as long as remainder of head. Prescutum and presutural scutum yellow with a very narrow darkened median line. Pleuron yellow to brownish yellow. Wing with stigma indistinct, pale yellow. Distance between tips of R 4 and R 5 about four times as long as distance between tips of R 1 and R 4. Tip of outer gonostylus bispinous, inner spine smaller. Interbase oval, tip significantly expanded laterally; laterally producing into a narrow, apically acute outgrowth. Description. Male. Body length 7.5–7.6 mm (excluding rostrum), wing length 6.5–6.7 mm, rostrum length 0.4–0.5 mm, antenna length 0.9–1.0 mm. Head (Fig. 4B). Pale brownish yellow with vertex dark brown. Setae on head dark brown. Antenna (Fig. 4C) brown with scape paler. Scape long cylindrical with tip slightly expanded, about 2.5 times as long as wide. Pedicel oval. Flagellomeres oval, apically tapering and elongated, with unilaterally arranged dark brown verticils; verticils on outer flagellomeres long, subequal in length to or slightly longer than corresponding flagellomere. Rostrum nearly as long as remainder of head, brownish yellow with dark brown setae. Palpus brownish yellow with brown setae. Thorax (Fig. 4D). Pronotum pale brown. Prescutum and presutural scutum yellow with a very narrow darkened median line. Postsutural scutum pale yellow with middle area darker. Scutellum pale yellow with middle area darker. Mediotergite yellow with two sides of base paler. Pleuron (Fig. 4A) yellow to brownish yellow. Setae on thorax dark brown. Fore coxa pale brownish yellow, mid and hind coxae yellow; trochanters yellow; remainder of legs pale brownish yellow. Setae on legs brown. Wing (Fig. 4E) tinged with pale brownish yellow, costal field slightly light yellow. Stigma indistinct, pale yellow. Veins yellow to brownish yellow. Venation: Sc ending just before fork of Rs, sc-r at its tip; distance between tips of R 4 and R 5 about four times as long as distance between tips of R 1 and R 4; cell dm about 1.5 times as long as wide; m-cu close to or just beyond fork of M. Halter yellow with knob paler. Abdomen (Fig. 4A). Tergite 1 dark brown; sternite 1 pale yellow. Segment 2–7 pale brownish yellow with caudal areas dark brown. Segment 8–9 dark brown. Setae on abdomen dark brown. Hypopygium (Fig. 5). Pale brownish yellow. Posterior margin of tergite 9 with a broad and shallow U-shaped emargination (Fig. 5A). Gonocoxite cylindrical with base slightly expanded. Setae on gonocoxite dark brown; shorter, slender and denser on inner side (Figs 5A–B). Outer gonostylus slightly curved with subtip slightly expanded; tip blackened and bispinous, inner spine smaller (Figs 5A–B, E). Inner gonostylus curved with basal half expanded (Figs 5A–B, E). Aedeagal complex with semen pump inverted pear-shaped (Figs 5C–D), ejaculatory apodeme very short and stout with tip trifurcated (Figs 5C–D); aedeagus rod-shaped with tip curled dorsally (Figs 5A–D). Parameres fused forming flattened transverse plate with long basal and apical parts, tip of apical part bent dorsally (Figs 5C–D). Interbase oval, tip significantly expanded laterally; laterally producing into a narrow, apically acute outgrowth (Figs 5C–D, F–G). Female. Unknown. Type material. Holotype ♂ (TYPE003 B01), China: Sichuan Province, Emeishan City, Mt. Emei, Linggongli (29°34′58″N, 103°17′24″E), 2016.V.21, Zehui Kang. Paratypes. 1♂ (TYPE003 B02), same data as holotype. 1♂ (TYPE 003 B03), China: Sichuan Province, Emeishan City, Mt. Emei, Qingyinge (29°34′27″N, 103°23′30″E), 2016.V.20, Zehui Kang. Distribution. Sichuan (Emeishan). Etymology. The name of the new species refers to H. (H.) pallidissimus Alexander, 1930, as the two species are very similar morphologically. Remarks. This new species is similar to H. (H.) pallidissimus from China by having a similar pale body coloration, but can be separated by the basal flagellomeres being oval (Fig. 4C), the femora, tibiae and tarsi of the legs being uniformly pale brownish yellow (Fig. 4A), and the tip of the interbase being significantly expanded laterally with an apically acute outgrowth (Figs 5C–D, F–G). In H. (H.) pallidissimus, the basal flagellomeres are short and crowded (Fig. 6C), the femora, tibiae and tarsi of the legs gradually change from yellow to brownish yellow (Fig. 6A), and the tip of the interbase is slightly expanded with an apically blunt outgrowth (Figs 7C–D, F–G).