S. Mahunka szerk.: Folia Entomologica Hungarica 57. (Budapest, 1996)

Dejean (1821) with two species: Plochionus brunneus was a nomen nudum, P. bonfilsii, however, was described as Lebia bonfilsii by Audinet-Serville in 1821. As AudinetServille's work antedates that of Dejean (see above), therefore, the generic name Plochionus is available since 1821. I have divided the family Haliplidae into two subfamilies, namely Haliplinae and Peltodytinae. The subfamily Haliplinae includes the tribes Haliplini and the newly described Brychiini (see below). The majority of the known genera and species belongs to Haliplini, while Brychiini includes the genus Brychius Thomson, 1859 only. The subfamily Peltodytinae embraces two genera, of which Peltodytes Régimbart, 1879 is represented by one species in Hungary. Brychiini trib. n. Type genus: Brychius Thomson, 1859 — Frons between eyes larger than one eye. Last segment of palpi subulate, shorter and narrower than penultimate one. Segment II of labial palpi somewhat flattened; interior apical angle tooth-like. Pronotum somewhat trapezoidal (rather than subquadrate), flattened dorsally, with a relatively long latero-basal stria at both sides. Lateral margins of prosternai process about parallel. Pronoto-elytral angle more or less distinct. Elytra finely and densely punctuated; surface more or less alutaceous; parasutural striae absent. Elytral margin (in lateral view) distinctly arched at shoulder. Broader basal part of epipleura with 1 or 2 longitudinal, rather irregular rows of larger punctures. Ventral punctuation obviously double: surface with obligate, sparsely distributed larger punctures and with fine, dense secondary punctuation among them. Lateral margins of metacoxae not bordered. Abdominal sternites I-IV covered by metacoxae. Abdominal sternite VII with a longitudinal, deeply incised furrow at apex. Dorsal (inner) face of metatibiae without a regular row of punctures bearing natatory hairs. Spurs of meso- and metatibiae smooth, not serrulate. There is a great confusion about the type designation of the genera Haliplus, Cnemidotus, Hoplitus and Peltodytes. As a crowning misfortune, it is practically impossible to identify the Fabrician Dytiscus impressus (the type of the genus Haliplus) from the original and subsequent descriptions. F. Balfour-Browne (1936) discusses the doubtful status of this species and, therefore, of the genus Haliplus. The original description might refer to almost any haliplid beetles. It is obvious that Fabricius himself and several early authors have described several different species (or a mixture of various species) under the name Dytiscus impressus. It is a wonder how some authors could identify this species in spite of entirely inadequate descriptions and illustrations as well as of inaccurate and impossible synonymies. Several writers have determined the Fabrician species as a Haliplus, while some others have considered it as a Peltodytes. After these it is difficult to see why Dytiscus impressus is universally recognized as a junior synonym of D. ruficollis De Geer, 1774 in recent times. In spite of all my efforts I have not found any lectotype designation for Dytiscus impressus or any explicit statement that the original material of this species contains at least one specimen of D. ruficollis. However, the doubt as to the identity of the Fabrician species is removed by Erichson (1837) who identifies Dytiscus impressus as Haliplus flavicollis, stating: "In Fabricius' Sammlung befindet sich eine ganze Reihe von Haliplus-Arten, sogar ein H. lineatocollis unter dem Namen Dyt. impressus: da aber