Rheocricotopus (Psilocricotopus) imperfectus Makarchenko & Makarchenko 2005

Rheocricotopus (P.) imperfectus Makarchenko & Makarchenko, 2005 Rheocricotopus (Psilocricotopus) imperfectus Makarchenko & Makarchenko, 2005: 126. Rheocricotopus (Psilocricotopus) imperfectus – Ashe & O’Connor 2012: 564. — Liu et al. 2014a: 24. Type material Holotype RUSSIA – Sakhalin • ♂; Dolinsky District, vicinity of Sokol, Belaya River; 15 Jul. 2001; E. Makarchenko leg.; FEBRAS. The type specimen of Rheocricotopus (P.) imperfectus was not examined. Distribution Except for the type locality of the Russian Far East, the distribution in Palaearctic China is highly doubtful. Remarks Makarchenko & Makarchenko (2005: 126) described the species based on a male from Sakhalin Island in the Russian Far East. The male is similar to that of R. (P.) chalybeatus in lacking acrostichal setae and a gonostylus sharply turned up apically, but separable in the low antennal ratio (AR 0.47), the wing with a reduced anal lobe and a moderately long costal extension (50 μm long), and the inferior volsella with a beak-like projection. In our opinion, the male of R. (P.) chalybeatus is characterized by the higher antennal ratio (AR ca 1.0), the wing with a right-angled anal lobe and a scarcely protruded costal extension, and the double-layered inferior volsella with a rounded apex. Later, Liu et al. (2014a: 24) recorded R. (P.) imperfectus Makarchenko & Makarchenko, 2005 from Palaearctic China based on many specimens. These records have no detailed morphological account. However, at least two voucher specimens (NK 08301, 09290) collected from Shaanxi Province do not belong to the true R. (P.) imperfectus because of the presence of two distinct acrostichal setae in the specimen NK 09290, and of more than 20 short acrostichal setae in the specimen NK 08301, which was confirmed by our close examinations of the vouchers. Until now, the female and immature forms are unknown.