Rheocricotopus (Psilocricotopus) hidakadeeus Sasa & Suzuki 2001

Rheocricotopus (P.) hidakadeeus Sasa & Suzuki, 2001 Fig. 5, Table 4 Rheocricotopus hidakadeeus Sasa & Suzuki, 2001b: 184. Rheocricotopus (Psilocricotopus) hidakadeeus – Ashe & O’Connor 2012: 564. — Yamamoto & Yamamoto 2014: 297. — Fu et al. 2016: 262. Type material Holotype JAPAN – Hokkaido • ♂; Nakasatsunai, Hidaka Mountain area; 26 Sep. 1998; H. Suzuki leg.; NSMT, NSMT-I-Dip 5367 [No. 401 (1): 51]. Description Male (n = 1) Total length 3.4 mm. COLOURATION. Body mostly dark brown, with scutal vittae, Sct and Pn blackish brown. Legs dark brown. HEAD. Temporals 10. AR 1.5. Clypeus with 14 setae. Lengths (μm) of Pm 1–5: 44, 74, 123, 172, 266, respectively. Pm 4 /Pm 3 1.4, Pm 5 /Pm 4 1.5. Pm 3 with 1 SCl. THORAX. Lateral Aps 9. Ac 15, longest 25 μm long; Dc 16 including 4 H; Pa 5; Scts 12. HP (Fig. 5A) nearly triangular, very large. WING (Fig. 5B). Length 2.3 mm. C well projected from end of R 4+5, extension 86 μm long. VR 1.1. R with at least 7 setae, R 1 with 1 seta, R 4+5 scratched. AnL developed, nearly right-angled. Sq with 10 setae. LEGS. P 1 with ti spur 52 μm long; P 2 with 2 ti spurs 20 and 17 μm long; P 3 with 2 ti spurs 54 and 22 μm long. P 2 with 4 Sch on ta 1. P 3 with ti comb of 13 bristles. Lengths and proportions of legs as in Table 4. ABDOMEN. Hypopygium (Fig. 5C) with AnP pointed apically, bearing 4 lateral setae. Gc 246 μm long, 3.1 × as long as broad at middle, with SVo somewhat thick, triangular, bearing rounded apex; IVo double-layered, with apically rounded dorsal lobe. Gs 106 μm long, nearly straight in outer margin; CD triangular, distinct. HR 2.33. Female, pupa and larva Unknown. Distribution The species is known only from the type locality, Hokkaido in Palaearctic Japan. Remarks The male is very similar to that of R. (P.) tokarakeleus Sasa & Suzuki, 1995 in the wing with a right-angled anal lobe and a long costal extension; the triangular superior volsella; the double-layered inferior volsella bearing an apically rounded dorsal lobe; and the triangular, distinct crista dorsalis. However, re-examinations of the holotypes of both species suggest that the males may be separated by stronger acrostichal setae (25 μm long in the longest seta), the thicker superior volsella, and the gonostylus with a nearly straight outer margin. In R. (P.) tokarakeleus, the acrostichal seta is at most 15 mm long, the gonocoxite bears a relatively thin superior volsella, and the gonostylus is roundly convex in outer margin. Additionally, the holotype of R. (P.) hidakadeeus is much darker than that of R. (P.) tokarakeleus. The male was described from a badly damaged single specimen as in R. (P.) tokarakeleus. The former was collected from Palaearctic Japan, while the latter is from Oriental Japan. We treat these as two different species, until more material is available for both.