Bembidion (Hydrium), LeConte, 1847

Bousquet, Yves, 2012, Catalogue of Geadephaga (Coleoptera, Adephaga) of America, north of Mexico, ZooKeys 245, pp. 1-1722 : 424-425

Subgenus Hydrium LeConte, 1847

Hydrium LeConte, 1847: 453. Type species: Bembidium levigatum Say, 1823 by monotypy. Etymology. From the Greek hydrias (from water), probably alluding to the habitat requirement of the species [neuter].

Eudromus Kirby, 1837: 55 [junior homonym of Eudromus Klug, 1835]. Type species: Peryphus nitidus Kirby, 1837 by monotypy. Synonymy established, under the name Platytrachelus Motschulsky, by Ganglbauer (1891b: 17). Etymology. From the Greek eu (well) and dromos (running) [masculine].

Platytrachelus Motschulsky, 1844: xi [junior homonym of Platytrachelus Schönherr, 1843]. Type species: Platytrachelus sibiricus Motschulsky, 1844 (= Bembicidium vitiosum Gemminger and Harold, 1868) designated by Netolitzky (1939: 9). Etymology. From the Greek platys (broad, wide) and trachelos (neck, by extension pronotum), alluding to the wide pronotum (" corselet presqu’aussi large que les élytres ") of the adult of Bembidion sibiricum [masculine].

Eurytrachelus Motschulsky, 1850a: 15. Replacement name for Platytrachelus Motschulsky, 1844. Synonymy established by Maddison (2012: 569). Etymology. From the Greek eurys (broad, wide) and trachelos (neck, by extension pronotum) [masculine].

Pogonidium Ganglbauer, 1891a: 151. Type species: Elaphrus laticollis Duftschmid, 1812 by monotypy. Synonymy established with the name Eudromus Kirby by Csiki (1906: 37). Etymology. From the generic name Pogonus [q.v.] and the Latin suffix - idium (little) [neuter].

Diversity.

Northern Hemisphere, with ten species in the Nearctic (four species) and Palaearctic (six species) Regions.

Identification.

Lindroth (1963b: 250-254, as nitidum and levigatum groups) covered all four North American species.

Taxonomic Note.

Habu and Uéno (1955: 45) described the subgenus Aptenidium (one Japanese species) in the genus Hydrium implying (though not discussed by the authors) a close relationship between the two genus-group taxa. Based on the original description, Aptenidium is likely not closely related to Hydrium .