Helius (Helius) gracillimus Alexander, 1938

Lv, Hanhuiying, Xu, Yuanyuan, Zhao, Yufei, Lin, Kejian & Zhang, Xiao, 2024, New records for the Helius Lepeletier & Serville fauna (Diptera, Limoniidae) of China, Biodiversity Data Journal 12, pp. e 115775-e 115775 : e115775-

Helius (Helius) gracillimus Alexander, 1938

Helius (Helius) gracillimus Alexander, 1938 - Alexander (1938): 143.

Materials

Type status: Other material. Occurrence: recordedBy: Yan Li; individualCount: 3; sex: males; lifeStage: adult; occurrenceID: 4932F87B-166F-50C2-AD8F-FB35D8AB10CA; Taxon: scientificName: Helius (Helius) gracillimus Alexander, 1938 ; order: Diptera ; family: Limoniidae ; genus: Helius ; subgenus: Helius ; Location: country: China; stateProvince: Inner Mongolia; county: Horqin Left Back Banner; locality: Daqinggou National Nature Reserve ; decimalLatitude: 42.76881; decimalLongitude: 122.21064; Event: samplingProtocol: sweeping; eventDate: 21 - Aug- 14; Record Level: institutionCode: QAU

Description

Diagnosis. Antenna long with base of first flagellomere paler, flagellomeres long cylindrical. Rostrum slightly longer than remainder of head. Prescutum and presutural scutum pale yellow dorsally with a pair pale yellow stripes separated by a narrow line and bordered by dark dots. Femora and tibiae pale brownish-yellow with tips slightly darker. Wing with large and brown stigma, brown spot at base of Rs, brown seam along cord. Venation with Sc ending nearly at fork of Rs, cell dm about 2.5 times as long as wide, m-cu beyond fork of M. Posterior margin of tergite 9 arched medially. Outer gonostylus slender and slightly curved with blackened and obtuse tip. Inner gonostylus with distal half curved and tapering apically. Interbase long, blade-shaped, outer margin darker. Aedeagus rod-shaped, tip expanded and trifid, middle spine tube-shaped and wavy, lateral spines triangle and shorter.

Male (Fig. 5 A). Body length 6.1–6.7 mm (excluding rostrum), wing length 7.0– 7.8 mm, rostrum length 0.5–0.6 mm, halter length 1.0– 1.2 mm.

Head (Fig. 5 B). Brownish-black. Setae on head brown. Antenna long, brown with base of first flagellomere paler. Scape cylindrical, twice as long as wide. Pedicel oval, tip slightly enlarged. Flagellomeres long cylindrical, tapering apically, with brown verticils. Rostrum slightly longer than remainder of head, dark brown with brownish-black setae. Palpus brown to dark brown with brownish-black setae, terminal segment elongated.

Thorax (Fig. 5 C). Pronotum yellow with middle area slightly darker. Prescutum and presutural scutum pale yellow, dorsally with a pair pale yellow stripes separated by a narrow line and bordered by dark dots; base of lines darkened by brown. Postsutural scutum brown, each lobe with a spot indistinctly bordered by pale yellow. Scutellum brown to dark brown. Mediotergite brown with indistinct median line. Pleuron brownish-yellow (Fig. 5 A). Setae on thorax dark brown. Coxae yellow with fore coxa slightly darker, trochanters yellow, femora and tibiae pale brownish-yellow with tips slightly darker, tarsi brown to dark brown. Setae on legs brown. Wing (Fig. 5 D) pale brown with cell sc darker; stigma large and dark brown, brown spot at base of Rs, brown seam along cord. Veins brown. Venation: Sc ending nearly at fork of Rs, sc-r near tip of Sc; m-m shorter than basal section of M 3; cell dm about 2.5 times as long as wide; m-cu more than 1 / 2 of its length beyond fork of M. Halter brownish-yellow with knob darker.

Abdomen. Tergites 1–8 brown, yellow laterally, with margins darker; tergite 9 brown. Sternites 1–8 yellow to brownish-yellow, sternite 9 dark brown. Setae on abdomen brown.

Hypopygium (Fig. 6 ). Posterior margin of tergite 9 arched medially (Fig. 6 A). Gonocoxite yellow, cylindrical, base with a stout, spinerous lobe (Fig. 6 A and B). Outer gonostylus brownish-yellow, slender and slightly curved, tip blackened and obtuse (Fig. 6 A, B and E). Outer gonostylus about 2 / 3 as long as inner gonostylus (Fig. 6 E). Inner gonostylus dark brown, distal half curved and tapering apically (Fig. 6 A, B and E). Interbase long, blade-shaped, outer margin darker (Fig. 6 A – D). Parameres sheet-like, medially fused, apically elongated and connecting to base of interbase (Fig. 6 C and D). Aedeagus rod-shaped, tip expanded and trifid, middle spine tube-shaped and wavy, lateral spines triangle and shorter (Fig. 6 A – D).

Female. Unknown.

Distribution

China (Inner Mongolia); North Korea, Russia, South Korea ( Oosterbroek 2023).

Notes

Helius (H.) gracillimus is an East Palaearctic species that occurs in Russia, North Korea and South Korea ( Oosterbroek 2023) and now recorded in China for the first time. For descriptions and illustrations of this species, also see Alexander (1938) and Podenas and Byun (2014). The species is closely related to H. (H.) subfasciatus Alexander, 1924 in the key by Xu et al. (2023) and can be distinguished by the brownish-yellow pleuron and the yellow coxae (Fig. 5 A). In H. (H.) subfasciatus , the pleuron is dark brownish-black and the coxae is brown ( Alexander 1924 b).

Figures

Figure 5. Helius (Helius) gracillimus Alexander, 1938. A habitus of male, lateral view; B head, lateral view; C thorax, dorsal view; D wing. Scale bars: 2.0 mm (A); 0.5 mm (B, C); 1.0 mm (D).

Figure 6. Helius (Helius) gracillimus Alexander, 1938. A male hypopygium, dorsal view; B male hypopygium, ventral view; C aedeagal complex, dorsal view; D aedeagal complex, ventral view; E outer gonostylus and inner gonostylus, dorsal view. Scale bars: 0.2 mm (A, B); 0.1 mm (C, D, E).