Species of the subgenus Empis (Xanthempis) from South Korea (Diptera, Empididae)

Abstract The subgenus Empis (Xanthempis) is newly recorded from South Korea with the following two species: E. (X.) sesquata (Ito, 1961) and E. (X.) suhi sp. n. A key to the known species of Xanthempis from Eastern Asia is presented. The distribution of Xanthempis in eastern Asia is briefly discussed.

In the present paper, two species are added to the fauna of South Korea, one of which is described as new to science. A key to the known species of the subgenus Xanthempis from eastern Asia is presented, mainly based on Shamshev (1998).

Materials and methods
Specimens used for our study are deposited in the Insect Collection of Kyungpook National University, Daegu, South Korea. Terminalia preparations of males were made by macerating the apical portion of the abdomen in cold 10% NaOH for 12-15 hours. After examination, the preparations were transferred to fresh glycerine and stored in microvial pinned below the dry-pinned specimen, and the descriptions are based on dry-pinned material. Morphological terminology for adult structures mainly follows McAlpine (1981), and the structures of the male genitalia follow Cumming and Wood (2009 Diagnosis. Mesoscutum with broad black median longitudinal vitta running also over scutellum and postnotum and elongate blackish spot between postpronotal lobe and suture. Occiput with contrastingly black, wedge-shaped spot including ocellar tubercle. Prothoracic spiracle yellow. Description. Male (Fig. 1). Body length 6.0-6.1 mm, wing length 8.5-8.6 mm. Head (Fig. 4) largely brownish yellow or yellow, faintly pale greyish pollinose; frons and face dark yellow, occiput with narrow contrastingly black, wedge-shaped spot including ocellar tubercle. Eyes dichoptic, ommatidia equally small. Frons broad, parallel-sided, with minute dark setulae laterally. Occiput (Fig. 6) with short sparse black setae arranged in two almost regular transverse rows on upper part and some pale setae behind mouth-opening. Ocellar tubercle with two short proclinate oc and some minute setulae. Antennal scape and pedicel brownish, postpedicel and stylus black; scape long, approx. five times longer than wide, with some black setulae; pedicel very short, subglobular, with circlet of black subapical setulae; postpedicel very long, narrow, subconical, approx. eight times longer than wide; stylus very short, nearly 0.3 times as long as postpedicel. Proboscis long, labrum approx. two times longer than head height; palpus yellow, with scattered blackish setulae.
Abdomen extensively yellow but tergites broadly brownish dorsally forming uniform vitta, subshiny; with scattered, mostly yellowish to brownish yellow setulae longer and darker on sternite 8 posteriorly. Hypopygium (Fig. 5) large, almost entirely yellow, only cerci narrowly brownish apically. Cercus rather large, with deep excision, dorsal arm long, broad, somewhat concave apically (lateral view), ventral arm short, finger-like; covered with dark minute setulae and bearing a moderately long seta on ventral arm. Epandrial lobe rather trapezoid, with upper posterior corner broadly rounded and lower posterior corner narrowly elongated; covered with dark setae longer along upper margin and on posterior corner. Hypandrium subtriangular viewed ventrally, with two black closely set spinules apically. Phallus strongly curved, attenuated on about middle part, with dorsal projection on subapical part (lateral view), long beak-like apical opening.
Female (described for the first time, Fig. 2). Body length 7.2-7.9 mm, wing length 8.2-8.5 mm. Very similar to male, but mesonotum with somewhat long setae; scutal lateral spots less distinct and sometimes absent. Cercus long, slender, brown, clothed in minute setulae.  Remarks. The species has been known for a long time only from the holotype male described by Ito (1961) from Honsyû Island (Hiroshima Prefecture) of Japan. Here we record E. sesquata from South Korea for the first time, where this species was collected Description. Male (Fig. 7). Body length 6.0-6.1 mm, wing length 8.2-8.8 mm. Head (Fig. 10) yellow, faintly pale greyish pollinose; occiput with narrow brown droplike spot including ocellar tubercle. Eyes dichoptic, ommatidia equally small. Frons broad, parallel-sided, with minute dark setulae laterally. Occiput (Fig. 12) with short sparse black setae on upper part and some pale setae behind mouth-opening. Ocellar tubercle with two short proclinate oc and some minute setulae. Antennal scape and pedicel brown, postpedicel and stylus black; scape long, 4.3 times longer than wide, with some black setulae; pedicel very short, subglobular, with circle of black subapical setulae; postpedicel very long, narrow, subconical, nearly 9.5 times longer than wide; stylus very short, 0.2 times as long as postpedicel. Proboscis long, labrum 2.5-3.0 times longer than head height; palpus yellow, with scattered blackish setulae.
Abdomen extensively yellow, but tergites broadly brownish dorsally forming uniform vitta (except tergite 8), subshiny; mostly yellowish to brownish yellow setulae longer laterally, segment 8 with black setae posteriorly. Hypopygium (Fig. 11) large, almost entirely yellow, only cerci narrowly brownish apically. Cercus rather large, with deep excision; dorsal arm long, broad, somewhat concave apically (in lateral view), ventral arm short finger-like; covered with dark minute setulae and bearing one moderately long seta on ventral arm. Epandrial lobe rather trapezoid, with upper posterior corner broadly rounded and lower posterior corner narrowly elongated; covered with dark short setae somewhat long along upper margin and on posterior corner. Hypandrium subtriangular in ventral view, with two black closely set spinules apically. Phallus strongly curved, somewhat broad near base, otherwise of more or less uniform thickness, with small dorsal tubercle closer to short beaklike apical opening.
Distribution. Palaearctic: South Korea. Remarks. In the scutal pattern, the new species is similar to E. belousovi Shamshev, 1998 andE. zlobini Shamshev, 1998 known from the Russia Far East (including Sakhalin Island) and to E. japonica Frey, 1955 known from Hokkaido and Kuril Islands (Kunashir) (Shamshev 1998). Empis suhi sp. n. can be distinguished from these species as it has been given in the key.
Etymology. The species is named in honor of Prof. Sang Jae Suh, Daegu in order to express our sincere thanks to him during the course of this study.

Discussion
At the present the subgenus Xanthempis is known exclusively from the Palaearctic region with 53 described species. There are eight species known in Eastern Asia, including the Russian Far East, Mongolia, the Korean Peninsula, and Japan. The subgenus Xanthempis is recorded from South Korea for the first time with the following two species: E. (X.) sesquata (Ito) and E. (X.) suhi sp. n. Empis sesquata is found in both the Korean Peninsula and Japan. The new species is similar to E. belousovi Shamshev, 1998 andE. zlobini Shamshev, 1998 from Russian Far East (including Sakhalin Island), and to E. japonica Frey, 1955 known from Hokkaido and Kuril Islands (Kunashir) (Shamshev 1998). Empis kovalevi Shamshev and E. richteri Shamshev are distributed on the Asian continent, and E. stercorea Linnaeus widely spreads in the Palaearctic region. Xanthempis has not been reported from China yet; however, some species of the subgenus may occur in northeast China. Further collections and investigations of Xanthempis from these areas may provide additional data on the fauna and distribution of this subgenus in Asia.