Xylota abiens Meigen

(Korean name: cheong-lam-saeg-heo-ri-kkot-deung-e)

Figs 1P, 2P, 3 A–E, 8A–D, 13E

Xylota abiens Meigen, 1822: 218 (type locality: Europe; type ♀, NMW); Hippa, 1968: 186 (taxonomic discussion); Hippa, 1978: 64 (taxonomic discussion); Violovitsh, 1986: 140, 142 (in Siberian key); Peck, 1988: 224 (in Palaearctic catalog); Kim J.I. et al., 1994a: 116 (fauna of Mt. Gwangdoksan); ESK & KASAE, 1994: 291 (in Korean checklist); Kim J.I., 1995b, 145 (fauna of Byonsan peninsula); Kim J.I., 1996: 178 (fauna of Mt. Bangtaesan); Park, 1998: 86 (Insects in Gangwon-do); Han et al., 1998: 152 (Korean catalog); Mutin & Barkalov, 1999: 495 (in species key); Speight, 1999: 216, 217 (in European key); Vujić & Milankov, 1999: 124, 126 (in key of Balkan peninsula); Han & Choi, 2001: 214 (in Korean catalog); Stubbs & Falk, 2002: 333, 340 (color illustration); Bartsch et al., 2009: 404, 406 (color illustration and diagnosis); Paek et al., 2010: 232 (in Korean checklist); Huang & Cheng, 2012: 669 (illustration and diagnosis); Han et al., 2014: 29 (in Korean catalog); Ohara et al., 2014: 522 (in Japanese catalog).

Musca semulator Harris, 1780: 112 (type locality: England; type lost).

Zelima subabiens Stackelberg, 1952: 326 (type locality: Russia, Leningrad Prov.; holotype ♂, ZISP).

Zelima abiens: Sack, 1932: 373 (in Palaearctic key); Shiraki, 1930: 64, 71 (in key with description); Hokuryukan, 1965: 214 (description with color photograph); Kim C.W. & Nam, 1982b: 130 (fauna of Mt. Gyebangsan, Sogyebangsan and Gachilbong).

Diagnosis. In Korea, only X. abiens, X. orientiflorum sp. n. and X. tarda share a light colored abdominal pattern in dark background, by which they can be separated from any other Korean Xylota species: abdominal terga 2 and 3 each with a pair of orange-yellow maculae (Fig. 2 P–S). Among these three species, the shape and size of maculae are species specific, and there is no problem distinguishing one another. Xylota tarda do have the largest maculae almost touching each other (Figs 2R, S, 6O, P). The other two species have smaller maculae, but maculae on tergite 3 are more or less square in X. abiens (Figs 2P, 3A) but widely rectangular in X. orientiflorum sp. n. (Figs 2Q, 5O). In addition, the latter species can be further separated by having the area anterior to ocellar triangle (vertical triangle anterior to ocellar triangle in male, and small area immediately anterior to ocellar triangle in female) covered with yellowish pile (Fig. 1Q) while the other two species do not have pile on that area (Fig. 1P, R–U). The latter species also has black pile on scutal area anterior to wing base, while others have yellow pile.

Description of Korean material. MALE. Body length 8.8–9.0mm; wing length 6.1–7.3mm; dark brown to black species with orange-yellow abdominal maculae (Figs 2P, 3A). Head black; face with dense yellow pollinosity (Fig. 3D, E); frons anterior to eye contiguity with dense yellow pollinosity (Figs 1P, 3D, E); area anterior to ocellar triangle (vertical triangle anterior to ocellar triangle) bare but posterior area covered with yellow pile (Fig. 1P). Thorax entirely black; scutum subshiny black with appressed short yellow pile, but posterior half sparsely with longer erect yellow pile mixed with short pile; anterior anepisternum covered with yellowish white pollinosity; posterior anepisternum with yellow pile and yellowish white pollinosity; anepimeron covered with yellow pile; katepisternum moderately covered with yellowish white pollinosity, dorsal posterior area with yellow pile; notopleuron with yellow pile; scutal area anterior to wing base with yellow pile; postalar callus with yellow pile; metasternum bare with white pollinosity. Wing hyaline except for brown pterostigma (Fig. 3A); halter yellowish white. Legs: femora almost entirely dark brown to black; pro- and mesotibiae yellow with subapico-ventral 3/5 dark brown; pro- and mesotaromeres 1–3 yellow; pro- and mesotaromeres 4 and 5 brown; metatrochanter ventrally with short calcar (subequal to basal width) (Fig. 3B); apico-ventral 1/3 of metafemur with two carinae covered with spinose setulae, remaining ventral area with few spinose setae, antero-dorsally and postero-ventrally with long yellowish white pile, apico-dorsal 1/3 with short black pile; basal 1/3 of metatibia yellow (Fig. 3B); metataromeres 1–3 dark brown and 4 and 5 black (Fig. 3B). Abdomen about 2.5x longer than wide (Figs 2P, 3A); terga 2 and 3 more or less parallel-sided; preabdominal terga dark brown in ground color; tergum 2 medially with a pair of orange-yellow and relatively small subrhombic maculae, separated from each other roughly by 1/3 of each macula width; tergum 3 with a pair of orange-yellow subsqure maculae, separated from each other by about 1/3 of each macula width (Figs 2P, 3A). Male genitalia (Figs 8 A–D, 13E): surstylus with dorsal lobe about twice as long as ventral lobe, long finger shaped and slightly bent ventrally in lateral view, densely covered with spinose setulae (Fig. 8A, B); ventral lobe of surstylus widely bulged, apically with scattered short setulae (Fig. 8A, B); cercus cordate in profile with long pale pile (Fig. 8A, B); lingula indistinct (Fig. 13E); fenestra small and elliptic in outline (Fig. 8A, B); spur of superior lobe reduced (Fig. 13E); superior lobe asymmetrical (Fig. 8A, B); each lateral arm of theca apico-dorsally with 4 thorny projections (Fig. 8A, B); aedeagus with ejaculatory hood medially with furrow in postero-ventral view, dorsally round in lateral view (Fig. 8C); ejaculatory process short (Fig. 8C); ejaculatory apodeme apically enlarged and bowl shaped.

FEMALE. Not examined. Bartsch et al. (2009) indicated that European female of this species has frons with a distinct pollinose fascia, the posterior margin of which is straight.

Material examined. SOUTH KOREA: Gangwon-do: 1♂, Inje-gun, Girin-myeon, Mt. Jeombongsan, Valley along Gangseon-ri, 7.VIII.1997, HY Han et al.; 1♂, Inje-gun, Sangnam-myeon, Bangdong-ri, Mt. Bangtaesan, north valley of Guryongduckbong, 1.VIII.1996, HY Han and HW Byun.

Distribution. Europe, Korea, Japan, Northeast China, Russia (From Urals to Sakhalin).