HYDROCHIDAE Hydrochus excavatus LeConte. Johnson: (Wickham 1911); Winnebago: (Wickham 1911). Distribution: Eastern USA, extending west to the Midwest. Hydrochus neosquamifer Smetana. Winnebago: Winnebago R., Lake Mills, TMM, 7/30/12. Distribution: Eastern USA, extending west to North Dakota in the north and Mississippi in the south. New state record . Hydrochus pseudosquamifer Miller. Jackson: South Big Mill Cr., Bellevue, CTH, 9/3/10; Kossuth: Black Cat Cr., Algona, MWB, 8/25/ 03. Distribution: Northern transcontinental in the USA. Hydrochus rufipes Melsheimer. Clinton: Brophy Cr., McCausland, CTH, 8/19/14; Linn: Wapsipinicon R., Troy Mills, CTH, 9/20/04. Distribution: Eastern USA, extending west to Wyoming in the north and Texas in the south. Hydrochus scabratus Mulsant. Buchanan: Pine Cr., Quasqueton, CTH, 9/1/15; Hardin: Tipton Cr., Buckeye, CTH, 7/30/99; Johnson: (Wickham 1911); Mitchell: Wapsipinicon R., McIntyre, MWB, 8/27/08. Distribution: Transcontinental in the USA. Hydrochus squamifer LeConte. Johnson: (Wickham 1911); Linn: Wickiup Nature Center (UV light), ELF, 7/28/04; Story: (Wickham 1911). Distribution: northern Transcontinental in the USA, extending south to Missouri and Kansas in the Midwest. Hydrochus subcupreus Randall. Black Hawk: Beaver Cr., Cedar Falls, MWB, 8/6/12; Cedar: Sugar Cr., Wilton, CTH, 8/23/01; Clinton: Brophy Cr., McCausland, CTH, 8/19/14; Muscatine: Pike Run, Nichols, CTH, 8/20/12. Distribution: Northeastern USA, extending west to Minnesota and Iowa.

Published as part of Hubbard, Todd, 2017, Aquatic Coleoptera (Dryopidae, Dytiscidae, Elmidae, Gyrinidae, Haliplidae, Helophoridae, Hydrochidae, Hydrophilidae, Noteridae, Psephenidae) of Iowa: Distributional Records and Notes, pp. 471-505 in The Coleopterists Bulletin 71 (3) on pages 496-497, DOI: 10.1649/0010-065X-71.3.471, http://zenodo.org/record/5376890