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

14 (23) Pronoto-elytral angle more or less distinct. Elytral margin (in lateral view) distinctly arched at shoulder. 15 (22) Metacoxal processes transversely truncate, not emarginate apically; common posterior margin of processes subrectilinear, not projecting medially. Protarsi of male with claws barely different in shape; both claws either entire or bifid. 16 (21) Segment III of protarsi at most slightly longer than segment II. Protarsi of male with normally curved, less elongate claws; both claws entire. Parameres with a regularly rounded or pointed apex; penis normal Hydrocoptus Motschulsky, 1853 17 (18) Elytral punctuation indistinct; surface with long, dense, distinct pubescence. Prosternai process spatuliform, relatively broad, weakly compressed laterally (Hydrocoptus incognitus, H. jonicus, H. palustris, H. springeri and H. striola) "palustris" species-group 18 (17) Elytral punctuation distinct; surface with short, sparse, indistinct pubescence. Prosternai process lanceolate, relatively narrow, strongly compressed laterally. 19 (20) Lateral margins of pronotum finely bordered. Metacoxal line simple (Hydrocoptus notatus and H. tristis) "tristis" species-group 20 (19) Lateral margins of pronotum not bordered. Metacoxal line double (Hydrocoptus umbrosus) "umbrosus" species-group 21 (16) Segment III of protarsi at least twice as long as segment II. Protarsi of male with barely curved, elongate claws; both claws bifid, deeply incised at tip. Parameres with an unciform apex; penis anomalous Schizoporus gen. n. 22 (15) Metacoxal processes distinctly emarginate apically; common posterior margin of processes bisinuate, angularly projecting medially. Protarsi of male with claws markedly different in shape; outer claw entire, inner claw bifid, more curved than outer one Hydroporinus Guignot, 1945 23 (14) Pronoto-elytral angle insignificant. Elytral margin (in lateral view) barely arched at shoulder. 24 (37) Metacoxal processes transversely or obliquely truncate, not emarginate apically; common posterior margin of processes either subrectilinear or projecting medially. 25 (36) Metacoxal processes transversely truncate, not emarginate apically; common posterior margin of processes subrectilinear, not projecting medially Hydroporus Clairville, 1806 26 (29) Lateral border of pronotum either absent or present but narrow (its broadest part either narrower or barely broader than elytral border). 27 (28) Body with distinct ash-coloured pubescence. Head conspicuously reddish in colour. Abdominal sternites densely punctuated (Hydroporus erytrocephalus) "erytrocephalus" species-group 28 (27) Body apparently bare. Head blackish or brownish in colour. Abdominal sternites sparsely punctuated (Hydroporus elongatulus and H. obscurus) "elongatulus" species-group