Two new species of Limonia Meigen, 1803 from Northwest China (Diptera, Limoniidae)

Abstract Two new species of Limonia Meigen, 1803, Limonia medexochasp. nov. and Limonia subcostasp. nov. are described and illustrated from Northwest China. The following five species are re-described and reported from China for the first time: L. macrostigma (Schummel, 1829), L. phragmitidis (Schrank, 1781), L. stigma (Meigen, 1818), L. sylvicola (Schummel, 1829) and L. taurica (Strobl, 1895). A key to adult males of Limonia from Northwest China is presented.

Northwest China includes the following six provinces: Xinjiang, Shaanxi, Ningxia, Gansu, Qinghai, and Inner Mongolia (western area). In this region the Altai Mountain A key to adult males of Limonia from Northwest China Body brown; wing with a distinct brown stigma (Figs 1, 3); occiput black brown without markings (Fig. 2); prescutum with three longitudinal stripes (Fig. 2); gonostylus with slender apex; paramere with slender and pointed apex (Figs 4-7) . Wing with three obvious dark spots (at basal Rs, apical Sc, and R 2 ) (Fig. 19); occiput dark brown (Fig. 18); paramere with slender apex (Fig. 23)  Diagnosis. Flagellar verticils 2 times length of corresponding segment. Prescutum with three dark-brown longitudinal stripes. Wing pale brown with distinct, large, brown stigma; apical Sc 1 slightly beyond base of Rs. Posterior margin of tergite 9 broadly emarginated. Paramere ending at 5/6 of aedeagus. Female, hypogynial valve 3.7 times longer than wide at base.
Redescription. Male (n = 10): body length 7-9 mm, wing length 8-9.5 mm. Head mostly dark brown (Figs 6, 7). Vertex dark brown. Occiput dull yellow. Head with black setulae. Antenna dark brown and 14-segmented; pedicel oval; flagellomeres pale brown, nearly cylindrical; flagellar verticils black, 2 times longer than corresponding segment. Rostrum and nasus brown to dark brown. Nasus 3/5 as long as rostrum. Labella pale yellow except inner margin brown, with black setulae. Palpi black brown with black setulae, terminal two segments pale brown.  Thorax mostly brown (Figs 1, 2). Cervical sclerite brown with black outer margin. Pronotum dull brown with black setulae. Prescutum with three dark-brown longitudinal stripes, median one with black setulae at outer margin. Scutum dark brown with black setulae at postero-lateral margin. Scutellum brown with tapered yellow median stripe. Mediotergite dark brown (Fig. 2). Mesopleura yellow to dark brown; subspiracular sclerite dull brown with pale-yellow spot at postero-lateral corner; episternum pale yellow to dark brown; katepisternum with black setulae and tapering, dark-brown marking at antero-lateral corner. Legs with coxae, trochanters yellow to pale brown except fore coxa yellow to dark brown; femora brown with one dark-brown, subapical ring; tibia brown; tarsi reddish brown to dark brown. Setulae on legs black. Wing hyaline, pale brown with large brown stigma at branching of R 1+2 ; apical Sc 1 slightly beyond base of Rs, Sc 2 apically reaching 1/5 of Rs; basal deflection of CuA 1 before branching point of M (Fig. 3). Halter: stem dull brown; knob bicolor, upper part pale brown to dark brown, lower part white (Fig. 1).
Abdomen (Fig. 1). Mainly dull brown. Each abdominal segment with one pale yellow ring at posterior margin. Abdomen covered with golden setulae.
Material examined. Remark. This is the first report of this species from China. The position of Sc relative to Rs and female body color shows the geographic variation. First, specimens from Xinjiang (Burqin, Altay Mountain) have Sc 1 slightly beyond basal Rs, Sc 2 reaching 1/5 of Rs (Fig. 3), similar wing venation with Savchenko's drawing (Savchenko 1985: 145, fig. 95.2), whereas specimens from Korea have Sc 1 reaching 1/3 of Rs, Sc 2 reaching 1/4 of Rs (Podenas and Podeniene 2017: 17, fig. 25). Moreover, female specimens from Xinjiang have the dark brown sternites, whereas Korean specimens have the yellow sternites (Podenas and Podeniene 2017:19).
Description. Male (n = 2): body length 9-10.5 mm, wing length 10-11 mm. Head mostly yellow (Figs 10, 11). Vertex dull yellow. Occiput dull yellow, covered with black setulae. Occipital marking dark brown, but pale brown at posterior part, Yshaped, with anterior marking linked with inner margin of eyes. Head with black setulae. Antenna 14-segmented; scape dark brown, pedicel yellowish brown, flagellomeres yellowish brown; flagellar verticils black, three times longer than corresponding segment. Nasus 1/2 as long as rostrum. Rostrum and nasus brown to dark brown. Labella pale yellow, with black setulae and inner margin with brown. Postgena light yellow with short narrow stripe near inner margin of eyes. Palpi dark brown with black setulae.
Thorax mostly yellow (Figs 10, 11). Cervical sclerite pale brown with black outer margin. Pronotum dull yellow with dull brown median stripe. Prescutum with one broad, dark-brown mid-longitudinal stripe and black setulae at lateral margin. Scutum dark brown with black setulae around outer margin. Scutellum dark brown with tapered yellow median stripe. Mediotergite dark brown (Fig. 11). Mesopleura entirely light yellow except katepisternum with dark brown margin at antero-lateral corner and subspiracular sclerite dull yellow; center of episternum with eight black setulae. Legs with coxae and trochanters yellow; femora yellowish brown with dark-brown terminal ring; tibiae yellowish brown, with dull brown subapical ring; tarsi reddish brown to dark brown. Setulae on legs black. Wing hyaline, pale brown; stigma pale brown with yellowish brown margin; Sc 1 apically reaching 3/5 of Rs; while Sc 2 apically reaching 3/4 of Rs; basal deflection of CuA 1 far before branching point of M. (Fig. 12). Halter with dull-brown stem and pale-brown to dark-brown knob (Fig. 10).
Abdomen mainly light yellow (Fig. 10). Dorsum with one dark-brown mid-longitudinal stripe. Abdominal segments 7-9 entirely dark brown; hypopygium mostly dark brown. Hypopygium . Posterior margin of tergite 9 with two finger-like, sclerotized protrusions that constrict at base and project outward at apex (Fig. 9). Gonocoxite wide at base and narrow at apex, longer than wide. Gonostylus with blunt apex and swollen basal protrusion that is strongly outward and hairy (Figs 9-11). Paramere reniform with small apical protrusion and rod-shaped; apex ended at 2/5 of aedeagus . Aedeagus complex; mid-ventral margin with strong protrusion which is long and rectangular in lateral view (Fig. 15); outer margin serrated; apex with small notch; spherical protrusion located mid-ventrally at base (Figs 13-16).
Remarks. This new species is very unique and differs from other known species of Limonia. This new species is somewhat similar to L. macrostigma (Schummel, 1829) in wing stigma. It can be separated from the latter by the following features: body yellow; occiput yellow with Y-shaped marking; gonostylus with obtuse apex; paramere with obtuse apex; aedeagus with strong mid-ventral protrusion. In L. macrostigma, the body is brown; the occiput is black brown; the prescutum has two lateral stripes; the gonostylus has a slender apex; the paramere has a slender and pointed apex; and the aedeagus has no mid-dorsal protrusion (Podenas and Podeniene 2017).
Diagnosis. Flagellar verticils shorter than corresponding segment. Pronotum dark brown. Prescutum with one narrow, deep-brown longitudinal stripe. Wing pale brown with three small, brown markings at base of Rs, apical Sc, and R 2 ; Sc 1 apically reaching 1/2 of Rs. Gonostylus with sharp apex and swollen base. Paramere ended at 3/5 of aedeagus. Aedeagus with unique H-shaped pattern at the mid-ventral margin. Female, hypogynial valve 2.1 times longer than wide at base.
Thorax mostly yellow (Figs 17, 18). Cervical sclerite pale brown, with black outer margin. Pronotum dark brown with black setulae. Prescutum with rather narrow, brown longitudinal stripe (anterior part wider than posterior part). Scutum pale yellow, with black setulae around outer margin. Scutellum pale yellow. Mediotergite pale yellow to yellow (Fig. 18). Mesopleura pale yellow to yellow; subspiracular sclerite pale yellow; anepimeron and katepisternum with black setulae. Legs with coxae and trochanters pale yellow; femora yellow with one dark-brown subapical ring; tibiae brown; tarsi brown to dark brown. Setulae on legs black. Wing hyaline, pale brown, with three small brown markings at base of R s , apical Sc, and R 2 ; Sc 1 apically reaching 1/2 of Rs; basal deflection of CuA 1 before branching point of M (Fig. 19). Halter: stem white; knob bicolor with upper part pale yellow to yellow while lower part white (Fig. 17).
Abdomen mainly yellow (Fig. 17). Sternite 8 reddish brown. Each abdominal segment with one pale-brown ring at posterior margin. Abdomen covered with golden setulae.
Female (n = 6): body length 8-10 mm, wing length 8-10 mm. Remark. This is the first report of this species from China.
Thorax mostly yellow (Figs 17, 18). Cervical sclerite yellow with black margin at antero-lateral margin. Pronotum dark brown, with black setulae. Prescutum with one brown, triangular longitudinal stripe (anterior part wider than posterior part); two setulae and longitudinal rows at middle. Scutum pale yellow, with black, oblique setulae at middle. Scutellum white. Mediotergite pale yellow, variegated with white (Fig. 27). Mesopleura pale yellow to yellow; subspiracular sclerite yellow; katepisternum with black setulae. Legs with coxae and trochanters yellow; femora dull yellow with one dark-brown subapical ring; tibiae brown with dark-brown subapical ring; tarsi brown to dark brown. Setulae on legs black. Wing hyaline, pale brown with one small grayish black marking at R 2 ; Sc 1 apically reaching 1/2 of Rs; basal deflection of CuA 1 before branching point of M (Fig. 28). Halter dull yellow; knob bicolor, with upper part dull yellow and lower part white (Fig. 26).
Abdomen mainly yellow (Fig. 26). Sternite 7 reddish brown. Each abdominal segment with one pale-brown ring at posterior margin. Abdomen covered with golden setulae.
Female resembling male in head, thorax, and wing. Female terminalia (Fig. 46) reddish brown. Cercus brown, with slightly arched dorsally at apex, slender, and 2 times longer than wide at base. Hypogynial valve 1.8 times longer than wide at base; lateral margin with oval, black marking (Figs 43, 44). Distribution. China (Shaanxi: Foping, Yangxian). Etymology. The specific name, from Latin, sub and costa (meaning "below the costa", refers to relative position of Sc to Rs.
Remarks. This new species is similar to L. pernigrina Alexander, 1938 in the wing marking and shape of the gonostylus. It can be separated from the latter by the following features: Sc 2 ended at 1/2 of Rs; branch pointing of Rs with small, whitish spot; posterior margin of tergite 9 with a narrow, median recession and long, finger-like protrusions (Figs 29,31). In L. pernigrina, the Sc 2 ends almost at branch of Rs; the branch pointing of Rs has a large whitish band that is linked anteriorly with the costal margin of the wing (Fig. 30); and the posterior margin of tergite 9 has a broad, median recession and short, finger-like protrusions (Alexander 1938b Diagnosis. Flagellar verticils 2 times longer than corresponding segment, but shorter in some specimens. Prescutum with one very broad brown mid-longitudinal stripe. Wings yellow variegated with grayish smoky markings, and three grayish spots at basal Rs, apical Sc and R 2 ; Sc 1 apically reaching 1/2-3/4 of Rs. Gonostylus long and slender. Posterior margin of tergite 9 emarginated. Gonostylus with sharp apex and swollen base. Apex of paramere ended at 3/4 of aedeagus. Ventral margin of aedeagus with H-shaped. Female, hypogynial valve 2.3 times longer than wide at base. Redescription. Male (n = 13): body length 6-8 mm, wing length 7-8 mm. Head dull brown (Figs 45,46). Vertex dull brown, with two yellow markings at outer margin near eyes (Fig. 46). Occiput dull yellow, covered with black setulae. Antenna yellow and 14-segmented; scape and pedicel dull brown; flagellomeres nearly cylindrical; flagellar verticils grayish yellow, 2 times longer than corresponding segment but short in some specimens. Nasus 1/2 as long as rostrum. Rostrum brown or dull brown. Labella pale yellow, except inner margin brown. Palpi brown, with black setulae.
Female (n = 4): body length 9 mm, wing length 8-10 mm. Female resembling male in head, thorax, and wing. Female terminalia pale yellow. Cercus yellow with slightly arched dorsally at apex, slender and 2.4 times longer than wide at base. Hypogynial valve 2.3 times longer than wide at base; lateral margin with broad, black marking (Figs 53, 54).
Thorax mostly brown (Figs 55, 56). Cervical sclerite dull brown, with black outer margin. Pronotum dark brown, with black setulae. Prescutum with five nar-row, brown longitudinal stripes, except middle and lateral stripes dark brown, lateral margin of prescutum with oval, dark marking (Fig. 56). Scutum reddish brown, with triangular yellow marking at postero-lateral margin, covered with sparse setulae at anterior margin. Scutellum dull yellow, with pale yellow markings at posterior margin. Mediotergite reddish brown, with two dull yellow markings at posterior margin (Fig. 56). Mesopleura reddish brown; subspiracular sclerite reddish brown; katepisternum with black setulae. Legs with coxae and trochanters dull yellow, except frontal coxae brown; femora yellow with dark-brown subapical ring; tibiae yellow with reddish-brown subapical ring; tarsi yellow to dark brown onwards. Setulae on legs black. Wings brown with three dull-brown spots at basal Rs, apical Sc, and R 2 ; Sc 1 apically reaching 7/10 of Rs (Fig. 57). Halter: stem white to brown; knob brown but white at posterior part.
Female (n = 5): body length 8.5-9 mm, wing length 9-10 mm. Female resembling male in head, thorax, and wing. Female terminalia pale yellow. Cercus yellow with slightly arched dorsally at apex, slender, and 3 times longer than wide at base. Hypogynial valve 5.3 times longer than wide at base; lateral margin with triangular, black marking (Figs 62, 63) Remark. This is the first report of this species from China.