Revision of the Chinese species of Dialineura Rondani, 1856 (Diptera, Therevidae, Therevinae)

Abstract The genus Dialineura Rondani is reviewed from China. One species, Dialineura elongata sp. n. is described as new to science. Two species, Dialineura nigrofemorata Kröber and Dialineura gorodkovi Zaitzev, are recorded from China for the first time. The female information of Dialineura henanensis Yang is also included here. A key to all the male species in the world and a biogeography map of China are presented.


Introduction
The genus Dialineura Rondani, 1856 belongs to the subfamily Therevinae (Diptera: Therevidae). Until now, this genus had twelve known species in the world, which are distributed in Palaearctic region, Oriental region (i.e. China) and Nearctic region (i.e. Canada and USA). Four species have been known to occur in China: D. kikowensis Ôuchi, 1943 from Zhejiang;D. affinis Lyneborg, 1968 from Sichuan;D. aurata Zaitzev, 1971 from Northeast China; D. henanensis Yang, 1999 from Henan.
Both Irwin and Lyneborg (1981a) and Webb and Irwin (1991) gave the detailed descriptions for body and male terminalia. Irwin and Lyneborg (1981a) emphasized mid coxa with long pile on posterior surface, and Webb and Irwin (1991) presented the description and figures for female terminalia. The genus Dialineura can be characterized by the following features: male eyes nearly contiguous medially; male and female frons pruinose; parafacial usually bare; scape of antenna more or less swollen, wider than first flagellomere; style one-segmented, terminal spine minute; prosternal furrow pilose; scutal chaetotaxy (pairs): np 3-6, sa 2, pa 1-2, dc 1-3, sc 1-2; cell m 3 open; middle coxa with long pile on posterior surface; hind femur with 6-10 anteroventral setae; in male genitalia, hypandrium absent; some species with substylus on gonocoxite; in female genitalia, spermathecal sac duct very short (Irwin and Lyneborg 1981a;Nagatomi and Lyneborg 1988;Webb and Irwin 1991).

Material and methods
The specimens were studied and illustrated with an OPTEC SMZ-B 2 stereomicroscope. Male genitalic preparations were made by removing and heating the apical portion of the abdomen in lactic acid at 180°C temperature for 15 min, and rinsing in water and 75% ethanol. Female genitalic preparations were made by removing and rinsing the abdomen in a saturated NaOH solution at room temperature for one day, staining with a saturated Chlorazol Black solution in 75% ethanol, and rinsing in 75% ethanol. After examination, preparations were transferred to fresh glycerin and stored in a microvial pinned below the specimen. The habitus photographs of adults were taken with a digital camera (Canon EOS 450D). Type specimens were deposited in the Entomology Museum of China Agricultural University (CAU), Beijing.

Taxonomy
Following is a key to the world male species of the genus Dialineura. The males of Dialinuera kikowensis Ôuchi, 1943 andDialineura aurata Zaitzev, 1971 are unknown, but we can identify females of these two species according to their distinct characters. The female D. kikowensis has two wide yellow vittae on mesonotum (Fig. 71), apical margin of cell m 3 narrower than cross-vein m-cu (see fig. 1, Ôuchi 1943), each tergites 2-7 with a median black spot (Fig. 71); female D. aurata has the body completely covered with dense bright yellow pubescence (Fig. 72).
Some figures cited in the key for the previously described species are from Zaitzev (1971Zaitzev ( , 1977, Nagatomi and Lyneborg (1988) and Webb and Irwin (1991). Femora black with yellow tips (Fig. 26), pterostigma of wing pale yellow (Fig. 25); apical epandrium narrow with a triangular medial invagination (Fig. 30), dorsal apodeme of aedeagus 1/2 as long as ventral apodeme (Fig. 34)  Scape of antenna very large, at least 1.5 times longer than first flagellomere (see fig. 7 Black pile distinctly present on fore femur; epandrium 1.5 times longer than subepandrial sclerite (see fig. 9, Zaitzev 1971 Diagnosis. Male mesonotum with 3 wide brown vittae, separated by 2 narrow pale yellow stripes, the central vitta with a narrow grey stripe in the middle; female mesonotum with 3 wide brown vittae, separated by 2 narrow pale brown stripes, the central vitta with a narrow pale brown to dark brown stripe in the middle. Mid and hind femora mostly yellow. Pterostigma of wing brown. Male apical epandrium relatively wide with a trapezoid medial invagination; gonocoxite relatively wide apically; dorsal apodeme of aedeagus nearly as long as ventral apodeme; distiphallus recurved and S-shaped. Description. Male. Body length 7.1-8.5 mm, wing length 6.0-7.0 mm. Head ( Fig. 1) with dense pale pubescence over black ground color, central area of frons brown. White pile from gena to occiput, black setae on ocellar tubercle and frons, parafacial bare, upper occiput also with some black postocular setae. Eyes reddish brown and nearly contiguous on upper frons. Antenna with dense pale pubescence over black ground color, except first flagellomere and style brown; black setae on scape long and thick, but those on pedicel short and thin; first flagellomere nearly bare; central part of first flagellomere widest; style resting apically on first flagellomere with a tiny distal spine; antennal ratio: 5.0 : 1.0 : 4.1 : 0.7. Proboscis pale yellow with some black parts marginally, covered with short brown pile; palpus pale yellow with white pile.
Abdomen with dense pale pubescence over black ground color, posterior margin of each segment pale yellow. White pile on abdomen, some black setae on terminalia. Male genitalia: Epandrium ( Fig. 10) elongated, 1.4 times longer than wide, apically with a trapezoidal medial invagination. Subepandrial sclerite rectangular, as long as cercus. Gonocoxite (Fig. 11) relatively wide apically. Dorsal apodeme of aedeagus  nearly as long as ventral apodeme; distiphallus recurved and S-shaped. Female. Body length 8.9-10.5 mm, wing length 6.5-7.9 mm. Most characters of female are similar to the male, with following exceptions: Frons ( Fig. 15) with dense dark brown pubescence over black ground color. Frons wide with 2 rows black setae, the narrowest point of frons 5 times wider than anterior ocellus. Antenna ratio: 4.2 : 1.0 : 3.9 : 0.7. Proboscis black but pale yellow marginally. Mesonotum ( Fig. 16) with 3 wide brown vittae, separated by 2 narrow pale brown stripes, the central vitta with a narrow pale brown to dark brown stripe in the middle. Fore coxa with a 1, av 1; mid coxa with a 3; hind coxa with a 3, d 1. Fore and mid femora without any prominent setae; hind femur with av 6, pv 2. Fore tibia with ad 4, pd 4, pv 4, apically with 5 setae; mid tibia with ad 3-4, av 5, pd 4-5, pv 5, apically with 5 setae; hind tibia with ad 8, pd 9-10, av 8, pv 9, apically with 3 setae. Pale pubescence on abdomen thinner than the male. Distribution. Palaearctic region: China (Shaanxi, Beijing); Oriental region: China (Yunnan) (Fig. 73). This is biogeographically part of North China Region and South China Region (Zhang 1999). Remarks. This new species is similar to D. henanensis Yang from China, especially in the recurved and S-shaped distiphallus and the relatively wide apical gonocoxite. But it can be separated from the following features: most areas of the mid and hind femora of both male and female are yellow; the pterostigma of the wing is brown; the halter knob is brown; the epandrium is wide apically with a trapezoidal medial invagination; the subepandrial sclerite is rectangular, as long as the cercus; the dorsal apodeme of aedeagus is nearly as long as the ventral apodeme. In D. henanensis, most areas of the mid and hind femora are black; the pterostigma of the wing is pale yellow; the halter knob is pale yellow; the epandrium is narrow apically with a triangular medial invagination; the subepandrial sclerite is triangular, nearly 2 times longer than the cercus; the dorsal apodeme of aedeagus is 1/2 as long as the ventral apodeme.
Etymology. The specific name refers to the elongated distiphallus, from the Latin adjective "elongatus" meaning prolonged. Diagnosis. Male mesonotum with 3 wide grey vittae, separated by 2 narrow pale yellow stripes, the central vitta with a narrow brown stripe in the middle; female mesonotum with 3 wide black vittae, separated by 2 narrow grey stripes, the central vitta with a narrow grey stripe in the middle. Pterostigma of wing pale yellow. Halter knob pale yellow. Male epandrium wide basally then suddenly narrow after middle line and with a triangular medial invagination apically; gonocoxite relatively wide apically; dorsal apodeme of aedeagus 1/2 as long as ventral apodeme; distiphallus recurved and S-shaped. Redescription. Male. Body length 7.3-8.5 mm, wing length 6.6-7.1 mm.

Dialineura nigrofemorata
Diagnosis. Male mesonotum with 3 wide black vittae separated by 2 narrow pale grey stripes. Pterostigma of wing yellow. Fore femur only with white pile. Male subepandrial sclerite very long; gonocoxite narrow apically and with substylus in interior margin.
Redescription. Male. Body length 8.2 mm, wing length 7.0 mm. Head (Fig. 43) with dense pale pubescence over black ground color, central upper area of frons brown. White to pale yellow pile from gena to occiput, black setae on ocellar tubercle and frons, setae on frons divided into 2 tufts, parafacial bare, upper occiput also with some black postocular setae. Eyes reddish brown and nearly contiguous on upper frons. Antenna with dense pale pubescence over black ground color, except first flagellomere and style brown; black setae on scape long and thick, but those on pedicel short and thin, first flagellomere nearly bare; central part of first flagellomere widest; style resting apically on first flagellomere with a tiny distal spine; antennal ratio: 3.6 : 1.0 : 3.5 : 0.9. Proboscis black with short brown pile; palpus brown with white pile.
Abdomen with dense pubescence over ground color, except tergite 1 and anterior margins of tergites 2-3 with very thin pubescence so that ground color is visible, posterior margin of each segment pale yellow. White pile on abdomen and terminalia. Male genitalia: Epandrium (Fig. 51) elongated, 1.3 times longer than wide, apically narrowed with a triangular medial invagination. Subepandrial sclerite slightly constricted in the central area, nearly 3 times longer than cercus. Gonocoxite (Fig. 52 Distribution. Palaearctic region: China (Liaoning) (Fig. 73), Russia. In China, this is biogeographically part of Northeast Region (Zhang 1999).

Dialineura gorodkovi
Remarks. Zaitzev (1971) firstly described Dialineura gorodkovi from Chukchi, Russia and gave the figures of the male genitalia. Lyneborg (1975) first recorded D. gorodkovi in north America. Webb and Irwin (1991) . 59) with dense pale pubescence over black ground color. White pile on frons and from gena to occiput, brown pile on ocellar tubercle, parafacial bare, upper occiput also with some black postocular setae. Eyes reddish brown and nearly contiguous on upper frons. Antenna with dense pale pubescence over black ground color; black setae on scape long and thick, but those on pedicel short and thin, scape also covered with long white pile, first flagellomere nearly bare; central part of first flagellomere widest; style resting apically on first flagellomere with a tiny distal spine; antennal ratio: 5.3 : 1.0 : 4.3 : 0.8. Proboscis brownish yellow with short brown pile; palpus pale brownish yellow with white pile.
Abdomen with dense pale pubescence over black ground color, except tergite 1 and terminalia with very thin pubescence so that ground color is visible, posterior margin of each segment pale yellow. White pile on abdomen and terminalia. Male genitalia: Epandrium (Fig. 65) elongated, 1.5 times longer than wide, apically narrowed with a triangular medial invagination. Subepandrial sclerite trapezoid, little longer than cercus. Gonocoxite (Fig. 66)  Diagnosis. Female mesonotum with two wide yellow vittae. Apical margin of cell m 3 narrower than cross-vein m-cu (Ôuchi 1943, p481, fig. 1). All femora (Fig. 67) entirely yellow. Each tergite of abdomen with a large black central spot.
Remarks. Ôuchi (1943) described only one female specimen of Dialineura kikowensis from Zhejiang, China and gave the figures of middle part of wing and abdomen in dorsal view. Yang (1999) included it into the key to species of Dialineura from China. We examine photos of the type specimen.  Zaitzev, 1971 http://species-id.net/wiki/Dialineura_aurata Figs 72, 73
Remarks. Zaitzev (1971) described four female specimens of Dialineura aurata from Palaearctic region including one from Northeast China. Zaitzev (1977) newly recorded three female specimens of Dialineura aurata from the Far East region of Russia. Yang (1999) included it into the key to species of Dialineura from China.  Zaitzev, 1971, lateral view.