New Metalimnobia crane flies (Diptera, Limoniidae) from China with an update of species distributions

Abstract Two new species of the genus Metalimnobia Matsumura, 1911 from southwest China, M. (M.) bicolorsp. nov. and M. (M.) caudifuscasp. nov., are described and illustrated. The new species can be distinguished from congeners by their wing patterns and male genitalia. New distributional data are given for the following species: M. (M.) bifasciata (Schrank, 1781), M. (M.) quadrinotata (Meigen, 1818) and M. (M.) tenua Savchenko, 1976. An updated key for all Chinese Metalimnobia crane flies is presented.


Introduction
Metalimnobia Matsumura, 1911 is a small genus in the family Limoniidae with 48 known species/subspecies. The genus is characterized by the following characters: body medium-sized to large, wing length more than 10 mm; antenna with 12 or 13 flagellomeres, palpus with five segments; wing distinctly patterned with dark brown spots or markings and often with smoky areas; R 1+2 and R 2 short and transverse, almost ending at the same level, basal section of CuA 1 before the fork of M; male gonocoxite with a large ventro-mesal lobe, inner gonostylus often divided into three lobes; ovipositor Wing with one or more spots at base (Fig. 2)  Diagnosis. Pleuron brownish black with brownish yellow stripe extending from pronotum to base of wing. Femora each with two rings, apical ring brown, subapical ring slightly paler and spreading over half of femora. Wing brownish with one or more brown spots at base, two large spots at origin and fork of Rs with upper parts brown and lower parts brownish black. Sc 1 ending beyond fork of Rs, Sc 2 shorter than Sc 1 ; basal section of CuA 1 before fork of M. Inner gonostylus divided into three lobes. Paramere with distal part long and nearly straight, tip flattened and bare.
Description. Male. Body length 10.5-10.8 mm, wing length 11.8-12.0 mm. Head (Fig. 1b) brown with vertex and frons dark brown. Setae on head dark brown. Antenna length 2.5-2.8 mm, brownish black with scape dark brown. Scape cylindrical; pedicel nearly globose; flagellomeres oval with long setae, each flagellomere slightly narrower than previous one, terminal flagellomere elongated. Rostrum dark brown with dark brown setae. Palpus brownish black with brownish black setae.
Thorax (Fig. 1c). Pronotum brownish black with lateral margins brown. Prescutum brown with four broad, brownish black longitudinal stripes, two lateral stripes about 1/2 length of median stripes. Scutum brown with middle area brownish yellow; each lobe with two large brownish black spots, anterior spot connected with lateral stripe of prescutum. Scutellum brownish black with middle area brownish yellow. Mediotergite brownish black, posterior area with two nearly confluent pale brownish yellow spots. Pleuron (Fig. 1a) brownish black with a brownish yellow stripe extending from pronotum to base of wing. Setae on thorax brownish black. Coxae brown; trochanters pale yellow; femora each brownish yellow with two rings, apical ring brown, subapical ring slightly paler and spreading over half of femora; tibiae brownish yellow with tip dark brown; tarsi brownish black, basal 1/3-1/2 of first tarsal segments brownish yellow. Setae on legs brownish black. Wing (Fig. 2) brownish with brown to brownish black pattern: long oval, brown spot at wing base ( Fig. 2a), often divided into two or three small spots (Fig. 2b, c); two large spots at origin and fork of Rs, each spot with upper part pale brown and lower part brownish black; stigma brown with each side darker; brown seams along cord, m-m, basal section of M 3 and base of CuA; obscure, irregular brownish clouds in most cells, darker near R 3 . Veins brownish yellow, darker in clouded areas. Venation: Sc long, Sc 1 ending beyond fork of Rs; Sc 2 a greater distance before tip of Sc 1 , Sc 1 1.5-2 times as long as Sc 2 ; basal section of CuA 1 1/2-2/3 of its own length before fork of M. Halter length 1.7-1.8 mm, white with knob dark brown.
Hypopygium (Fig. 3). Posterior margin of ninth tergite emarginate, each lobe with several setae. Gonocoxite slender with a large, elongate and caudally curved ventromesal lobe. Outer gonostylus broad, arched at 2/3 length, outer third narrowing into a flattened spine. Inner gonostylus divided into three lobes: innermost lobe long, slender and curved; dorsal fleshy lobe fingerlike with long setae; ventral fleshy lobe oval with long setae. Paramere wide basally with distal part long and nearly straight, tip flattened and bare. Aedeagus long, slightly enlarged before tip.
Distribution. China (Sichuan). Etymology. The specific name refers to the wing spots at the origin and fork of Rs which have brown upper parts and brownish black lower parts.
Remarks. Metalimnobia (M.) bicolor sp. nov. can readily be distinguished from all other Metalimnobia crane flies known from China by the wing spots at the origin and fork of Rs. This species has a somewhat similar wing to the widespread M. (M.) tenua but can be easily distinguished from the latter by the antenna with dark brown scape and brownish black pedicel, the mostly brownish black pleuron, the brown coxae, and the paramere being wide basally with a long and nearly straight distal part and a flattened tip (Figs 3, 4a, 4d). In M. (M.) tenua, the scape and pedicel of the antenna are yellowish brown, the pleuron is mostly yellowish brown, the coxae are pale yellow, and the paramere is subtriangular with an acute tip (Fig. 4b, e). Diagnosis. Pleuron yellow. Femora yellow with apical brown rings. Wing yellowish without spot at base. Sc 1 ending close to fork of Rs, Sc 2 longer than Sc 1 ; basal section of CuA 1 close to or beyond fork of M. Outer gonostylus broad, arched at 2/3 length, outer angle extended and darkened. Inner gonostylus undivided. Paramere with distal part long and nearly straight, tip blunt with several hairs on inside.
Remarks. Metalimnobia (M.) bifasciata is widely spread in the Palearctic and Oriental regions. In China, this species is known in many provinces and is now recorded in Sichuan for the first time. For descriptions and illustrations of this species, see Alexander (1918), Boardman (2007), Mao and Yang (2010), Matsumura (1911), Nakamura (2006), Podenas et al. (2006), Podenas and Gelhaus (2007) and Podenas and Byun (2016). Diagnosis. Pleuron yellow. Fore femur yellow with apical brown ring; mid and hind femora each with two rings, apical ring brown, subapical ring pale brown and spreading over half of femur. Wing grayish without spot at base. Sc 1 ending beyond fork of Rs, Sc 2 shorter than Sc 1 ; basal section of CuA 1 before fork of M. Inner gonostylus divided into three lobes; dorsal fleshy lobe arched at 2/3 length, tip pointed. Paramere with distal part long, slender and slightly curved outwards, tip angulate with tuft of hairs.
Description. Male. Body length 9.5-10.5 mm, wing length 11.5-13.0 mm. Head (Fig. 5b) brownish yellow with vertex brown and frons yellow. Setae on head brown. Antenna length 2.2-2.5 mm, yellow with flagellomeres brown. Scape cylindrical; pedicel nearly globose; flagellomeres oval with long setae, each flagellomere slightly narrower than previous one, terminal flagellomere elongated. Rostrum brown with dark brown setae. Palpus brown with dark brown setae. Thorax (Fig. 5c). Pronotum brown with lateral regions brownish yellow. Prescutum yellow with four broad, brown longitudinal stripes, lateral stripes about 1/2 length of median stripes. Scutum yellow, each lobe with two large pale brown spots, anterior spot connected with lateral stripe of prescutum. Scutellum yellow with lateral regions pale brown. Mediotergite yellow, base with two pale brown spots. Pleuron (Fig. 5a) yellow. Setae on thorax dark brown. Coxae yellow. Trochanters pale yellow. Fore femur yellow, tip with brown ring; mid and hind femora each yellow with two rings, apical ring brown, subapical ring pale brown and spreading over half of femur. Tibiae brown. Tarsi brown, bases of first tarsal segments slightly paler. Setae on legs dark brown. Wing (Fig. 5d) grayish with pale brownish yellow to pale brown pattern: large, pale brown spots at origin and fork of Rs; stigma pale brown with middle area paler; very pale brown seams along cord, m-m, basal section of M 3 and base of CuA; obscure, irregular pale brownish yellow clouds in most cells. Veins pale brownish yellow, darker in clouded areas. Venation: Sc long, Sc 1 ending beyond fork of Rs; Sc 2 a greater distance before tip of Sc 1 , Sc 1 1.2-3 times as long as Sc 2 ; basal section of CuA 1 1/4-1/2 of its own length before fork of M. Halter length 1.7-1.9 mm, pale yellow. Abdomen (Fig. 5a). Tergites 1-5 yellow to brownish yellow, tergites 6-8 brown. Sternites 1-6 yellow, sternites 6-8 brown. Hypopygium (Fig. 6). Posterior margin of ninth tergite emarginate, each lobe with several setae. Gonocoxite slender with short, rounded and apically blunt ventro-mesal lobe. Outer gonostylus broad, arched at 2/3 length, outer third narrowing into a flattened spine. Inner gonostylus divided into three lobes: innermost lobe long, slender and curved; dorsal fleshy lobe long and stout with long setae, arched at 2/3 length, tip pointed; ventral fleshy lobe oval with long setae. Paramere wide basally with distal part long, slender and slightly curved outwards, tip angulate with tuft of hairs. Aedeagus long and slender.
Female. Unknown. Distribution. China (Xizang/Tibet). Etymology. The specific name refers to the caudal segments of the abdomen being uniformly brown.
Remarks. Some Metalimnobia crane flies that occur in China also have a tuft of hairs at the tip of the parameres (e.g., bifasciata, quadrimaculata, rectangularis and xanthopteroides). ) rectangularis by the wing pattern (caudifusca has no spot at the base of the wing, but quadrimaculata and rectangularis have a spot at the base of their wings) and the shape of the paramere (Fig. 4c, f-h). Notably, the type specimens of M. (M.) yunnanica deposited in USNM and NHM were examined and showed that its wing had pale spots at the base.

Metalimnobia (Metalimnobia) quadrinotata (Meigen, 1818)
Limnobia quadrinotata Meigen, 1818: 144  Diagnosis. Pleuron brownish yellow. Femora each brownish yellow with two rings, apical ring black, subapical ring paler and spreading over half of femora. Wing brownish with one or more spots at base. Sc 1 ending beyond fork of Rs, Sc 2 longer than Sc 1 ; basal section of CuA 1 before fork of M. Inner gonostylus divided into three lobes. Paramere with distal part long and curved ventrally, tip flattened and bare.
Distribution ( Remarks. Metalimnobia (M.) quadrinotata is widespread in the Palearctic region. In China, this species was previously known in three provinces and is now recorded in Hebei, Jilin and Neimenggu for the first time. For descriptions and illustrations of this species, see Savchenko (1985), Podenas et al. (2006), Podenas and Gelhaus (2007), Mao and Yang (2010) and Podenas and Byun (2016).

Metalimnobia (Metalimnobia) tenua Savchenko, 1976
Metalimnobia quadrinotata tenua Savchenko & Krivolutskaya, 1976: 151. Type locality: Russia, several localities in Eastern Siberia and the Far East Diagnosis. Pleuron brownish yellow, variegated by darker areas. Femora each brownish yellow with two rings, apical ring black, subapical ring slightly paler and spreading over half of femora. Wing brownish with two relatively large spots at base. Sc 1 ending beyond fork of Rs, Sc 2 shorter than Sc 1 ; basal section of CuA 1 before fork of M. Inner gonostylus divided into three lobes. Paramere subtriangular, tip slightly acute and bare (Fig. 4b, e).
Remarks. Metalimnobia (M.) tenua is widespread in the Palearctic region. In China, this species was previously only known in Ningxia and is now recorded in Sichuan for the first time. For descriptions and illustrations of this species, see Savchenko and Krivolutskaya (1976), Savchenko (1983), Podenas and Gelhaus (2007) and Mao and Yang (2010).