First record of the genus Empidideicus Becker, 1907 (Diptera, Mythicomyiidae) in China and the Oriental Region, with description of a new species

Abstract Empidideicus Becker, 1907 is newly recorded from China and the Oriental Region, with one new species, E.pentagoniussp. n., described and illustrated. Observations are provided on the biology of E.pentagoniussp. n. visiting flowers of Stemonamairei (Levl.) Krause (Liliflorae, Stemonaceae). A key to the genera of Mythicomyiidae known to occur in China is provided.

The genus Empidideicus is reported from China and Oriental Region for the first time, and a new species, E. pentagonius sp. n., is described. Observations are provided on the flower visiting behaviour of E. pentagonius in northwestern Yunnan, China. A key to the genera of Mythicomyiidae from China is presented. The distribution of the new species updates the easternmost distribution of the genus and more species might be distributed in the dry-hot valleys of the Oriental and eastern Palaearctic regions.

Material and methods
Specimens were collected by sweeping flowers of Stemona mairei (Levl.) Krause in June beside the Jinsha River in southwest China (28°21'18.91"N, 99°12'52.20"E). The photos of adults visiting flowers were taken with a Canon 5D digital Camera and combined into figures using Adobe Photoshop CS3 software. Photos of male genitalia were taken by KEYENCE VHX-2000. The specimens were studied and illustrated with an Olympus SZ61 stereo microscope. Preparations of genitalia were made by macerating the apical portion the abdomen in cold 10% NaOH for 12-15 h. After examination, dissected material was transferred to fresh glycerine and stored in a microvial together with the specimen. The holotype and other specimens examined are deposited in the Entomological Museum of the China Agricultural University, Beijing (CAU). Diagnosis. Head with ocellar tubercle yellowish, frons and face yellowish with a cupshaped brown area between frons and face; thorax with two yellowish subtriangular marks anterolaterally, with a subtrapezoidal yellowish brown area posteriorly; katepisternum with upper 1/3 yellow; aedeagal apodeme base semicirclular, with acute tip in dorsal view, aedeagal apodeme arched in lateral view; epiphallus pentagonal, with narrow tip in dorsal view. Description. Male. Body length 0.8-1.4 mm, wing length 1.1-1.4 mm. Head black and yellowish, eyes red, bare; ocellar tubercle black, ocelli yellowish; eyes dichoptic, 2 × width of ocellar tubercle, frons and face bare, yellowish, except a cup-shaped brown area between frons and face; occiput black. Antenna (Fig. 11) yellowish brown, scape semicircular nearly twice wider than long; pedicel trapezoidal, slight wider than long; first flagellomere ovoid, nearly 1.7 × longer than wide; second flagellomere about 1/3 length of first flagellomere, cylindrical, about 3 × longer than wide, with minute apical style. Antennal ratio: 1:2:8. Proboscis brown except base with a yellowish quadrilateral area laterally, nearly 2 × length of head. Thorax (Fig. 10) black and yellowish, mesonotum mostly black except edge yellowish, postpronotal lobe yellowish, anterior with two yellowish subtriangular marks laterally, and a subtrapezoidal yellowish brown area posteriorly, mesonotum with three brown prealar bristles, anepisternum and anepimeron mostly yellow except edge of front and bottom black, katepisternum mostly black except upper 1/3 yellow.

Key to genera of Mythicomyiidae from China
Scutellum yellowish brown. Legs yellow except femora and tarsi brown. Legs with short brown hairs; tibiae with short black hairs and bristles, tarsi with short black hairs.   Abdomen with all tergites dark brown, except posterior margin with narrow pale brown band, and with yellow posterolaterally. Sternites yellowish mostly, except yellowish brown centrally, and pale laterally.
Male genitalia brown and black (Figs 6-8). Epandrium brown except edge black, nearly as long as wide, cercus well exposed, narrow and long, tip acutely in ventral view; gonocoxa L-shaped, nearly 2 × longer than wide, with acute tip, gonostylus triangular with acute tip in lateral view; aedeagal apodeme base semicircle, extremely long, and narrowly apically, with acute tip in dorsal view, aedeagal apodeme arch in lateral view; epiphallus pentagonal, with narrow tip in dorsal view, epiphallus tip sickle-shaped in laterally view.

Remarks.
The new species is similar to E. legulicoxa Gharali & Evenhuis, 2010 (Iran), but it can be separated from the latter by the following features: the frons and face are yellowish, except a cup-shaped brown area between frons and face; the katepisternum mostly black except for the upper 1/3, which is yellow; the abdomen with all tergites is dark brown, except the posterior margin, which has a pale brown narrow band, and laterally, which is yellow posteriorly. In E. legulicoxa, the frons is yellowish white, and slightly depressed medially with a large squarish brown spot medially, and the lower 3/4 of the katepisternum is yellowish white; the abdomen is predominantly yellow and with medial brown color dorsally, tergites I-III are brown with undulating posterior margins (Babak et al. 2010). (1) E. pentagonius sp. n. rests on the flowers of Stemona mairei for a few minutes to half an hour, apparently feeding pollen or nectar. (2) After visiting a flower, much pollen was observed on the body of flies, which visited one flower after another. (3) E. pentagonius sp. n. is considered an important pollinator of S. mairei in June, but this species is rare in July, and beetles became the dominant visitors of S. mairei instead. (4). Different from other species of Stemona, S. mairei has a faint fragrance instead of a rotting smell (Chen et. al. 2017), which might attract E. pentagonius. (5) The eggs and larvae of the flies were not found in the flower, and the life history of E. pentagonius is unknown (Figs 2-5).