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

both Erichson and Régimbart definitely intended to base a genus on Dytiscus caesus (D. impressus as erroneously determined by Panzer). Nevertheless, the use of the generic name Cnemidotus by Erichson is merely a misapplication. Peltodytes, however, should be regarded to have been properly published. It should be based on the species that were included in Cnemidotus by Erichson. Since it originally contained only Dytiscus caesus, consequently, that species should be considered (by monotypy) as the type of the genus Peltodytes. Hoplitus Clairville, 1806 was published as a name of separate status but it was nearly always mentioned in synonymy with Haliplus by the subsequent writers. (It is possible to contend that it is an intended emendation of Haliplus, but no direct evidence appears in the original publication of it. Hoplitus, therefore, should be considered as a distinct genus.) Three species were originally included in it: Dytiscus fulvus Fabricius, 1801, D. impressus Fabricius, 1787 and D. obliquus Fabricius, 1787. The type, Dytiscus fulvus, was subsequently designated by Crotch (1870). If the type designation for the genera Haliplus Latreille, 1802 and Cnemidotus Illiger, 1802 is taken literally (as I believe it should be), and the nominal species Dytiscus impressus Fabricius, 1787 is a senior subjective synonym of Haliplus flavicollis Sturm, 1834, then the name Haliplus should hereafter be applied to the genus called recently as Liaphlus Guignot, 1928. Haliplus and Cnemidotus become objective synonyms. Both are senior subjective synonyms of Hoplitus Clairville, 1806 and of Liaphlus Guignot, 1928. Hoplitus and Liaphlus are objective synonyms. Haliplidius Guignot, 1928 is the name remaining for the genus that includes Dytiscus obliquus. Haliplinus Guignot, 1939 is the genus that includes Dytiscus ruficollis De Geer, 1774 and its congeners. Peltodytes may be retained in its customary sense. The problems about the type designation of Haliplus and Cnemidotus will revive: if the lectotype is designated for the Fabrician Dytiscus impressus and it is a species other than Haliplus flavicollis; or D. impressus is considered as an erroneously applied name for a certain species different from the Fabrician one. At all events the designation of Dytiscus obliquus as the type species for the genus Haliplus by F. Balfour-Browne cannot be maintained by any means, unless the International Commission of the Zoological Nomenclature validates it. The genus Ilybius Erichson, 1832 originally included three species (Dytiscus ater De Geer, 1774; D. fenestratus Fabricius, 1781 and D. fuliginosus Fabricius, 1792). According to Nilsson et al. (1989) the type species (designated by Westwood in 1838) is Dytiscus fenestratus. However, Dytiscus ater was previously designated as the type by Laporte de Castelnau (1834). This does not affect the present usage of the generic name Ilybius. The names Dytiscus variegatus Gravenhorst, 1807, Dyticus variegatus Germar et Kaulfuss, 1817 and Lacophilus variegatus Sturm, 1834 are subjective synonyms. Each name was separately validated but they were proposed for the same species: Laccophilus variegatus auct. The first two names, however, are both junior primary homonyms of Dyticus variegatus Fourcroy, 1785 and, therefore, unavailable. The generic names Bidessus and Deronectes have generally been attributed to Sharp (1882). However, most writers have overlooked the fact, that these names (applied to groups of species in the genus Hydroporus) had previously been published by Bedel (1881). They were validated without a formal description, merely by listing a number of previously established valid species.