Simulium (Wilhelmia) xichangense An, Tan & Wang 2025, sp. nov.

Simulium (Wilhelmia) xichangense An, Tan & Wang sp. nov. urn:lsid:zoobank.org:act: 34871151-537A-448D-800A-C587F2ACF81A (Figure 1) Female. Body length: 2.5 mm. Body brown. Head. Slightly narrower than width of thorax. Brown black. Face black and covered with white powder and long yellowish-white hairs. Frons black and covered with white powder and long yellowish-white hairs. Facetted eye dichotic, located in the middle of the head and on either side of the antennae. Antenna composed of scape, pedicel and nine flagellomeres. Antenna brownish black except scape, pedicel and basal 1/2 of the first flagellomere are yellowish-brown. Mouth parts brownish black. Maxillary palp composed of five palpomeres, dark brown. Fifth palpomere slender and curved. Third palpomere moderate swollen. The length of sensory vesicle 0.6~0.7 times of the third palpomere. Thorax. Brownish black. Scutum brownish black with 3 dark narrow longitudinal strings in the shape of strings, densely covered with blonde hairs, without silver-white spots. Pleural membrane hairy. Katepisternum bare. Postscutellum black with a small amount of long white hairs. Scutellum brownish black with numerous long white hairs. Halter. Yellow brown except basal portion darkened. Legs. Foreleg: dark brown except tibia brown. Midleg: dark brown except tibia brown. Hindleg: coxa black; trochanter and femur brownish black; tibia dark brown except basal 1/5 yellowish white; basitarsus yellowish white except basal 1/5 and apical 1/5 brown, 2nd tarsomere brown except basal 1/2 yellowish-brown, the rest of tarsi brown. Claws long and simple. Calcipala well-developed. Pedisulcus well-defined. Wing. Length 3.0 mm. Broad and Transparent. Without scales. Veins nearly transparent except costa and radius brown. Costa has spinules and hairs. Subcosta bare. Basal portion of radius hairy. Veins are simple, and the radial sector do not branch. Abdomen. Black with blonde hairs. 11 segments. Genitalia. Genital plate subtriangular, covered with several hairs, with its inner margins widely separated, each end with transparent narrow uncinate long projection. Genital fork of inverted-Y form, with slender stem; arms of genital fork with distinct stout outer projections, without inner projections. Paraproct in ventral view similar to the shape of shoes, strongly pigmented, with short to medium-long hairs on lateral and ventral surfaces. Cercus in ventral view oval, and with numerous short to medium-long hairs. Spermatheca oval, 1.4 times as long as its greatest width, brown except duct unpigmented. Male. Unknown. Pupa. Unknown. Larva. Unknown. Type material. Holotype. ♀, China, Sichuan province, Xichang city. Paratypes. 3♀, same data as the holotype. Etymology. The species name xichangense refers to the locality name, Xichang city, where this new species was collected. Remarks. The new specimen was first identified and marked by Juanjie Tan in the collection of specimens. This new species belongs to subgenus Wilhelmia as defined by Enderlein (1921). The main identification characteristics of the subgenus Wilhelmia are that the pleural membrane hairy, basal portion of radius hairy, each end of genital plate with transparent narrow uncinate long projection. It is closely related to S. (W.) pinnatum Chen, Zhang and Jiang, 2016 from Gansu province in China. However, there are some characteristics that are clearly different from those of the S. (W.) pinnatum, such as wing length longer than body length, the length of sensory vesicle and the shape of the reproductive fork arm.