Systropus coalitus, Cui, Weina & Yang, Ding, 2010

Cui, Weina & Yang, Ding, 2010, Two new species and two new synonyms of Systropus Wiedemann, 1820 from Palaearctic China (Diptera: Bombyliidae), Zootaxa 2619, pp. 14-26 : 18-20

Systropus coalitus sp. nov.

( Figs. 8–15 , 37–39 )

Diagnosis. Mesoscutum with three lateral pale yellow spots. Scutellum black, with pale pile on posterior border. Metasternum yellow with a wide black stripe on both sides, anterior portion coalesced. Hind coxa and trochanter black, femur brownish yellow, tibia black except apical 1/4 yellow, tarsus black.

Description. Male. Body length 16 mm, wing length 6 mm.

Head black except lower frons, face and gena yellowish, ocellar tubercle red brown. Setulae on head yellowish, except lower frons, face and gena with short silvery white pile; upper occiput with black setulae along eye margin. Antennal scape pale yellow with brown apex, with short black setulae; pedicel dark brown, with short black setulae; first flagellomere black, flat and bare; antennal ratio 2: 1: 1.7. Proboscis black except basal ventral portion mostly yellowish brown, bare; palpus brown with very short pale setulae.

Thorax black with yellow spots. Setulae on thorax pale and dark brown; yellow areas with pale setulae. Propleuron pale yellow. Postpronotal lobe pale yellow. Mesoscutum with three pale yellow lateral spots, anterolateral spot transverse and finger-like, midlateral spot onion-shaped, anterolateral spot connected with midlateral spot by narrow yellowish brown band (this character variable), posterolateral spot triangular. Postalar callus yellow. Scutellum black, with pale pile on posterior portion. Anepimeron with anterior portion dark brown and posterior portion gray, posterior margin with pale setulae. Metasternum yellow with a wide black stripe on both sides, anterior portion coalesced.

Fore leg yellow except femur black, third to fifth tarsomeres yellowish brown; 3 dark brown dorsal setulae present at tip of fifth tarsomere. Mid coxa black with elliptical yellow anterior portion at apex; trochanter brown; femur dark brown; tibia yellow; second to fifth tarsomeres brown to dark brown. Hind coxa and trochanter balck; femur brownish yellow; tibia black except apical 1/4 yellow; tarsus black. Claws shining black, pulvilli yellow. Setulae on legs mostly short and recumbent, those on black area black while those on yellow area yellowish brown. Hind tibia with three rows of black spine-like setae (6 ad, 3 av and 4 pv). Mid and hind tarsi with black spine-like ventral setae.

Wing with pale smoky infuscation; veins brownish. Halter stem yellowish brown, knob black dorsally, ventral surface and margin pale yellow.

Abdomen yellow, tergite 1 black with anterior margin wider than scutellum; tergites 2–5 with dark brown mid-longitudinal stripes; tergite 6 to hypopygium dark brown. Petiolus formed from segments 2–4 and anterior part of segment 5; segments 5–8 inflated, ovate. Setulae on abdomen very short, recumbent and black, except tergite 1 with pale postero-lateral setulae, tergites 2–5 with pale setulae on yellow portions.

Male genitalia ( Figs. 8–13 ). Epandrium ( Figs. 8–9 ) as long as wide, subquadrate, with very long and slender surstylus blackened at dorsal apical portion and pointed; cercus rather subtriangular, with large and wide blackened tubercle starting near inner ventral corner and protruding beyond dorsal outer margin in dorsal view. Sternite 10 ( Fig. 9 ) wider than long, V-shaped in dorsal view. Gonocoxite ( Figs. 10–11 ) longer than wide, narrowing posteriorly, with numerous black bristle-like setulae; gonostylus ( Figs. 10–11 ) cylindrical, its tip obtuse and blackened in lateral view. Midposterior part of dorsal band with pair of large circular convexities; median epiphallic lobe in ventral view acute; paired lateral epiphallic lobe absent.

Female. Body length 17 mm, wing length 7 mm. Similar to male, but mesoscutum with three isolated pale yellow lateral spots. Apical part of sternite 8 with black median epiphallic lobe triangular in ventral view ( Figs. 14–15 ).

Type material. Holotype male, CHINA: Beijing, Huairou, Baiquanshan (40° 18’ N; 116°37’ E), 26.VIII. 2009, Weina Cui. Paratypes 1 male, 1 female, CHINA: Beijing, Huairou, Baiquanshan (40° 18’ N; 116°37’ E), 26. VIII. 2009, Weina Cui; 1 male, CHINA: Beijing, Huairou, Baiquanshan (40° 18’ N; 116°37’ E), 26. VIII. 2009, Yan Li; 1 female, CHINA: Beijing, Huairou, Baiquanshan (40° 18’ N; 116°37’ E), 26. VIII. 2009, Dan Zhou.

Distribution. China (Beijing).

Etymology. The specific name refers to the metasternum yellow with two wide black stripes joined anteriorly.

Remarks. The new species is somewhat similar to S. excisus ( Enderlein, 1926) from China (Gangdong) in having similar antennal coloration, but it can be separated from the latter by the apex of the hind tibia yellow and the metasternum yellow with two wide black stripes joined anteriorly. In S. excisus , the apex of the hind tibia is black; the metasternum is yellow with two wide black stripes not joined anteriorly ( Nagatomi et al. 1991).

Figures

FIGURES 8 – 15. Systropus coalitus sp. nov. 8. Male genitalia, posterior view; 9. epandrium, cercus and sternite 10, ventral view; 10 – 11. gonocoxite and gonostylus, ventral and lateral views; 12 – 13. phallus, dorsal and lateral views. Female. 14. Apical portion of sternite 8, ventral view; 15. apex of abdomen, lateral view.

FIGURES 37 – 39. Systropus coalitus sp. nov. (male). 37. Body, lateral view; 38. mesoscutum and scutellum, dorsal view; 39. metasternum, posteroventral view.