Rheocricotopus (Psilocricotopus) oiraprimus Sasa 1991

Rheocricotopus (P.) oiraprimus Sasa, 1991 Fig. 6, Table 5 Rheocricotopus oiraprimus Sasa, 1991: 72. Rheocricotopus (Psilocricotopus) longiligulatus Yamamoto & Yamamoto, 2017: 75. Syn. nov. Eukiefferiella amamipubescia [nec Sasa, 1990] – Sasa & Okazawa 1992: 108. Rheocricotopus (Psilocricotopus) oiraprimus – Saether et al. 2000: 161. — Ashe & O’Connor 2012: 566. — Yamamoto & Yamamoto 2014: 297. Rheocricotopus (Psilocricotopus) imperfectus [nec Makarchenko & Makarchenko, 2005]. – Liu et al. 2014a: 24, partim. Material examined Holotype of Rheocricotopus oiraprimus JAPAN – Aomori • ♂; Towada, Oirase River; 2 Jul. 1990; M. Sasa leg.; NSMT, NSMT 5989 [No. 202:51]. The type specimens of R. (P.) longiligulatus were not examined. Other material examined CHINA – Shaanxi • 1 ♂; Ankang, Ningshan, Xunyangba; 33°54′ N, 108°54′ E; 17 Aug. 1994; W.J. Bu leg.; NK 09290 [labelled as “ R. imperfectus ”]. JAPAN – Shizuoka • 1 ♂; Aoi-ku, Ashikubo, Funatoike Pond, stream; 35°2′ N, 138°22′ E; 77 m a.s.l.; 10 Oct. 1981; H. Niitsuma leg.; PCHN • 1 ♂; Aoi-ku, Ushizuma, Abe River; 35°4′ N, 138°22′ E; 99 m a.s.l.; 26 Oct. 1994; H. Niitsuma leg.; PCHN. Description Male (n = 3) Total length 2.3–2.6, 2.5 mm. COLOURATION. Head dark brown on vertex. Thorax largely blackish brown except yellow pleural membrane and HP. Abdomen (Fig. 6A–B) variously bicoloured; T I entirely yellow; T II or II–V yellow with lateral and middle longitudinal dark brown bands, or extensively dark brown; T IV–IX or VI–IX entirely dark brown. Legs largely brown; P 1 darker than P 2–3; all fe somewhat paler in anterior part. HEAD. Temporals 2–4, 3. AR 0.49–0.52, 0.51. Clypeus with 9–12, 10 setae. Lengths (μm) of Pm 1–5: 34–37 (2); 44–59 (2); 106–118 (2); 116–118 (2); 214 (2), respectively. Pm 4 /Pm 3 1.0–1.1 (2); Pm 5 /Pm 4 1.8–1.9 (2). Pm 3 with 3–4, 3 SCl on circular depression. THORAX. Aps 4–8, 6, divided into 2 groups. Ac 4 (2) near to apex of Scu, longest 20–25 (2) μm long; Dc 9–14, 12, including 2–4, 3 H; Pa 3; Scts 8 (2). HP (Fig. 6C) large, circular, and occasionally indistinct in part. WING (Fig. 6D). Length 1.7–1.8, 1.7 mm. C moderately projected, extension 54–64, 58 μm long. VR 1.1. R with 4–6, 5 setae; R 1 and R 4+5 without setae. AnL much reduced. Sq with 0–2, 1 seta. LEGS. P 1 with ti spur 39 (2) μm long; P 2 with 2 ti spurs 22–23, 23 and 18–20, 19 μm long; P 3 with 2 ti spurs 47–52, 49 and 22–23, 22 μm long. P 2 with one Sch on ta 1. P 3 with ti comb of 12–13, 12 bristles. Lengths and proportions of legs as in Table 5. ABDOMEN. Hypopygium (Fig. 6E) with AnP pointed apically, bearing 7–9, 8 lateral setae. Gc 165–185, 175 μm long, 2.9–3.0, 3.0 × as long as broad at middle, with SVo thick, roundly protruded; IVo triangular. Gs (Fig. 6F) 76–81, 80 μm long; CD distinct, triangular or quadrate. HR 2.16–2.27, 2.20. Pupa and larva Unknown. Distribution This species has been known from Palaearctic Japan. Here, a record from Oriental China (Shaanxi) is added. Remarks A re-examination of the holotype male of R. (P.) oiraprimus Sasa, 1991 disclosed that actually eight scutellar setae are present and AR is 0.52, not 16 and 0.41, respectively, as in the original description (Sasa 1991: 72). Although the hypopygium is mounted in a supine position on the slide, a crista dorsalis is distinct at the subapex of gonostylus. The acrostichal setae are indistinct because of the poor mounting. We re-examined the voucher specimens identified as R. (P.) imperfectus by Liu et al. (2014a: 24). One (NK 09290) of these specimens possesses strong antepronotal setae in two groups and a few strong acrostichal setae near the apex of scutum. The male is well consistent with that of R. (P.) oiraprimus in morphological features, although the apices of hypopygial gonostylus are crushed. This is the first record of R. (P.) oiraprimus in the Oriental region. The features of this male comply with the description of R. (P.) longiligulatus Yamamoto & Yamamoto, 2017, and thus are conspecific although the holotype of the latter species were not examined here. The female adult was described under R. (P.) longiligulatus by Yamamoto & Yamamoto (2017: 78) from Tokushima, Japan. According to them, tergite IX is elevated, but undivided. Sasa & Okazawa (1992: 108) redescribed Eukiefferiella amamipubescia Sasa, 1990 based on two males from Toyama Prefecture, Japan. After re-examinations of these vouchers, Yamamoto et al. (2015: 108) concluded that these specimens belong to R. (P.) oiraprimus. The male is similar to that of R. (P.) bifasciatus Wang & Zheng, 1991 in the bicoloured abdomen, the rounded humeral pit, the wing with a much-reduced anal lobe and a moderately extended costal vein, a triangular inferior volsella, and a distinct crista dorsalis, but is separable by the antepronotal setae located in medial and lateral groups, the scutum anteriorly with a few strong acrostichal setae (longest setae 20–25 μm), the tergite II with lateral and middle dark brown bands, the legs with uniformly brown tibiae, and a thick, roundly protruded superior volsella. The male of R. (P.) bifasciatus is characterized by the antepronotal setae positioned laterally only, the many relatively weak acrostichal setae (longest setae 10–12 μm), the entirely yellow tergite II, the legs distinctly bicoloured (tibia dark brown, apically with a broad white band), and the thin, triangular superior volsella.