Hydraena

Hydraena is a genus of minute moss beetles in the family Hydraenidae. There are more than 990 described species in Hydraena.

Systematics

There are at least 924 species in the genus Hydraena:Hydraena abbasigili Jäch, 1988^{i c g}Hydraena abdita Orchymont, 1948^{i c g}Hydraena abyssinica Régimbart, 1905^{i c g}Hydraena accurata Orchymont, 1948^{i c g}Hydraena achaica Jäch, 1995^{i c g}Hydraena acumena Perkins, 2011^{i c g}Hydraena adelbertensis Perkins, 2011^{i c g}Hydraena adrastea Orchymont, 1948^{i c g}Hydraena aethaliensis Breit, 1917^{i c g}Hydraena affirmata Perkins, 2007^{i c g}Hydraena affusa Orchymont, 1936^{i c g}Hydraena africana Kuwert, 1888^{i c g}Hydraena akameku Perkins, 2011^{i c g}Hydraena akbesiana Audisio, De Biase and Jäch, 1993^{i c g}Hydraena albai Sáinz-Cantero, 1993^{i c g}Hydraena alberti Balfour-Browne, 1950^{i c g}Hydraena alcantarana Ienistea, 1985^{i c g}Hydraena algerina Kaddouri, 1992^{i c g}Hydraena alia Orchymont, 1934^{i c g}Hydraena aliciae Jäch and Díaz, 2005^{i c g}Hydraena allomorpha Lagar and Fresneda, 1990^{i c g}Hydraena alluaudi Régimbart, 1906^{i c g}Hydraena alpicola Pretner, 1931^{i c g}Hydraena altamirensis Díaz Pazos and Garrido Gonzalez, 1993^{i c g}Hydraena altapapua Perkins, 2011^{i c g}Hydraena alternata Perkins, 1980^{i c g}Hydraena alterra Perkins, 1980^{i c g}Hydraena alticola Skale and Jäch, 2008^{i c g}Hydraena altiphila Perkins, 2011^{i c g}Hydraena amazonica Perkins, 2011^{i c g}Hydraena ambiflagellata Zwick, 1977^{i c g}Hydraena ambigua Ganglbauer, 1901^{i c g}Hydraena ambiosina Perkins, 2007^{i c g}Hydraena ambra Perkins, 2011^{i c g}Hydraena ambripes Perkins, 2011^{i c g}Hydraena ambroides Perkins, 2011^{i c g}Hydraena americana Jäch, 1993^{i c g}Hydraena amidensis Jäch, 1988^{i c g}Hydraena ampla Perkins, 2011^{i c g}Hydraena anaphora Perkins, 1980^{i c g}Hydraena anatolica Janssens, 1963^{i c}Hydraena ancylis Perkins, 1980^{i c g}Hydraena ancyrae Jäch, 1992^{i c g}Hydraena andalusa Lagar and Fresneda, 1990^{i c g}Hydraena andreinii Orchymont, 1934^{i c g}Hydraena angulicollis Notman, 1921^{i c g b}Hydraena angulosa Mulsant, 1844^{i c g}Hydraena angustata Sturm, 1836^{i c g}Hydraena anisonycha Perkins, 1980^{i c g}Hydraena antaria Perkins, 2007^{i c g}Hydraena antiatlantica Jäch, Aguilera and Hernando, 1998^{i c g}Hydraena antiochena Jäch, 1988^{i c g}Hydraena apertista Perkins, 2011^{i c g}Hydraena apexa Perkins, 2011^{i c g}Hydraena appalachicola Perkins, 1980^{i c g}Hydraena appetita Perkins, 2007^{i c g}Hydraena aquila Perkins, 2011^{i c g}Hydraena arabica Balfour-Browne, 1951^{i c g}Hydraena arachthi Ferro and Jäch, 2000^{i c g}Hydraena arcta Perkins, 2007^{i c g}Hydraena arenicola Perkins, 1980^{i c g}Hydraena argutipes Perkins, 1980^{i c g}Hydraena ariana Janssens, 1962^{i c g}Hydraena arizonica Perkins, 1980^{i c g}Hydraena armata Reitter, 1880^{i c g}Hydraena armatura Perkins, 2014^{i c g}Hydraena armeniaca Janssens, 1968^{i c g}Hydraena armipalpis Jäch and Díaz, 2000^{i c g}Hydraena armipes Rey, 1886^{i c g}Hydraena aroensis ^{i c g}Hydraena arunensis Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena ascensa Perkins, 2007^{i c g}Hydraena assimilis Rey, 1885^{i c g}Hydraena ateneo Freitag, 2013^{i c g}Hydraena athertonica Perkins, 2007^{i c g}Hydraena atrata Desbrochers des Loges, 1891^{i c g}Hydraena atroscintilla Perkins, 2011^{i c g}Hydraena attaleiae Ferro, 1984^{i c g}Hydraena audisioi Jäch, 1992^{i c g}Hydraena aulaarta Perkins, 2011^{i c g}Hydraena aurita Jäch, 1988^{i c g}Hydraena australica Zwick, 1977^{i c g}Hydraena australula Perkins, 2007^{i c g}Hydraena austrobesa Perkins, 2011^{i c g}Hydraena avuncula Jäch, 1988^{i c g}Hydraena bacchusi Perkins, 2011^{i c g}Hydraena bactriana Janssens, 1962^{i c g}Hydraena bakriensis Skale and Jäch, 2011^{i c g}Hydraena balearica Orchymont, 1930^{i c g}Hydraena balfourbrownei Bameul, 1986^{i c g}Hydraena balkei Perkins, 2011^{i c g}Hydraena balli Orchymont, 1940^{i c g}Hydraena barbipes Zwick, 1977^{i c g}Hydraena barricula Perkins, 1980^{i c g}Hydraena barrosi Orchymont, 1934^{i c g}Hydraena bedeli Berthélemy, 1992^{i c g}Hydraena belgica Orchymont, 1930^{i c g}Hydraena beniensis Perkins, 2011^{i c g}Hydraena benjaminus Jäch and Díaz, 2006^{i c g}Hydraena bensae Ganglbauer, 1901^{i c g}Hydraena bergeri ^{i c g}Hydraena berthelemyana Jäch, Díaz and Dia in Jäch, Dia and Díaz, 2006^{i c g}Hydraena berytus Jäch, 1986^{i c g}Hydraena beyarslani Jäch, 1988^{i c g}Hydraena bicarina Perkins, 2014^{i c g}Hydraena bicarinova Perkins, 2011^{i c g}Hydraena bicolorata Jäch, 1997^{i c g}Hydraena bicuspidata Ganglbauer, 1901^{i c g}Hydraena bidefensa Perkins, 2007^{i c g}Hydraena bifunda Perkins, 2011^{i c g}Hydraena bihamata Champion, 1920^{i c g}Hydraena biimpressa Perkins, 2007^{i c g}Hydraena billi Zwick, 1977^{i c g}Hydraena bilobata Jäch and Díaz, 1998^{i c g}Hydraena biltoni Jäch and Díaz, 2012^{i c g}Hydraena bimagua Jäch, 1986^{i c g}Hydraena birendra Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena biseptosa Perkins, 2014^{i c g}Hydraena bispinosa Pu, 1951^{i c g}Hydraena bisulcata Rey, 1884^{i c g}Hydraena bitruncata Orchymont, 1934^{i c g}Hydraena bituberculata Perkins, 1980^{i c g}Hydraena biundulata Perkins, 2011^{i c g}Hydraena blackburni Zaitzev, 1908^{i c g}Hydraena bodemeyeri Jäch and Díaz, 2001^{i c g}Hydraena boetcheri Orchymont, 1932^{i c g}Hydraena bolivari Orchymont, 1936^{i c g}Hydraena boliviana Perkins, 2011^{i c g}Hydraena bononiensis Binaghi, 1960^{i c g}Hydraena borbonica Fairmaire, 1898^{i c g}Hydraena bosnica Apfelbeck, 1909^{i c g}Hydraena brachymera Orchymont, 1936^{i c g}Hydraena bractea Perkins, 1980^{i c g}Hydraena bractoides Perkins, 1980^{i c g}Hydraena brahmin Perkins, 2011^{i c g}Hydraena breedlovei Perkins, 1980^{i c g}Hydraena brevis Sharp, 1882^{i c g}Hydraena britteni Joy, 1907^{i c g}Hydraena brittoni Zwick, 1977^{i c g}Hydraena bromleyae Jäch, 1986^{i c g}Hydraena browni Perkins, 1980^{i c g}Hydraena bubulla Perkins, 2011^{i c g}Hydraena bulgarica Breit, 1916^{i c g}Hydraena buloba Perkins, 2011^{i c g}Hydraena buquintana Perkins, 2011^{i c g}Hydraena buschietanni Freitag, 2021^{i c g}Hydraena buscintilla Perkins, 2011^{i c g}Hydraena busuanga Freitag and Jäch, 2007^{i c g}Hydraena calcarifera Janssens, 1959^{i c g}Hydraena californica Perkins, 1980^{i c g}Hydraena campbelli Perkins, 1980^{i c g}Hydraena canakcioglui Janssens, 1965^{i c g}Hydraena canticacollis Perkins, 1980^{i c g}Hydraena capacis Perkins, 2007^{i c g}Hydraena capensis Perkins, 2014^{i c g}Hydraena capetribensis Perkins, 2007^{i c g}Hydraena cappadocica Jäch, 1988^{i c g}Hydraena caprivica Perkins, 2014^{i c g}Hydraena capta Orchymont, 1936^{i c g}Hydraena carbonaria Kiesenwetter, 1849^{i c g}Hydraena carica Jäch, 1988^{i c g}Hydraena carinocisiva Perkins, 2011^{i c g}Hydraena carinulata Rey, 1886^{i c g}Hydraena carmellita Perkins, 2011^{i c g}Hydraena carniolica Pretner, 1970^{i c g}Hydraena castanea Deane, 1937^{i c g}Hydraena castanescens Freitag and Jäch, 2007^{i c g}Hydraena cata Orchymont, 1936^{i c g}Hydraena catalonica Fresneda, Aguilera and Hernando, 1994^{i c g}Hydraena catherinae Bameul and Jäch, 2001^{i c g}Hydraena caucasica Kuwert, 1888^{i c g}Hydraena cavifrons Perkins, 2011^{i c g}Hydraena cephalleniaca Jäch, 1985^{i c g}Hydraena cervisophila Jäch, 1992^{i c g}Hydraena challeti Perkins, 2011^{i c g}Hydraena cheesmanae Perkins, 2011^{i c g}Hydraena chenae Pu, 1951^{i c g}Hydraena chersonesica Jäch, Díaz and Przewozny, 2007^{i c g}Hydraena cherylbarrae Perkins, 2011^{i c g}Hydraena chiapa Perkins, 1980^{i c g}Hydraena chiesai Janssens, 1965^{i c g}Hydraena chifengi Jäch and Díaz, 1999^{i c g}Hydraena chobauti Guillebeau, 1896^{i c g}Hydraena christinae Audisio, De Biase and Jäch, 1996^{i c g}Hydraena christoferi Jäch and Díaz, 2005^{i c g}Hydraena ciliciensis Jäch, 1988^{i c g}Hydraena circulata Perkins, 1980^{i c g b}Hydraena cirrata Champion, 1920^{i c g}Hydraena clarinis Perkins, 2011^{i c g}Hydraena claudia Freitag and Jäch, 2007^{i c g}Hydraena clavicula Perkins, 2014^{i c g}Hydraena clavigera Zwick, 1977^{i c g}Hydraena clemens Jäch and Díaz, 2006^{i c g}Hydraena clinodorsa Perkins, 2011^{i c g}Hydraena clystera Perkins, 2011^{i c g}Hydraena cochabamba Perkins, 2011^{i c g}Hydraena colchica Janssens, 1963^{i c g}Hydraena colombiana Perkins, 1980^{i c g}Hydraena colorata Perkins, 2011^{i c g}Hydraena colymba Perkins, 1980^{i c g}Hydraena compressipilis Jäch and Díaz, 1998^{i c g}Hydraena concepcionica Perkins, 2011^{i c g}Hydraena concinna Orchymont, 1932^{i c g}Hydraena confluenta Perkins, 2011^{i c g}Hydraena confusa Pu, 1951^{i c g}Hydraena connexa Orchymont, 1932^{i c g}Hydraena converga Perkins, 2007^{i c g}Hydraena coomani Orchymont, 1932^{i c g}Hydraena cooperi Balfour-Browne, 1954^{i c g}Hydraena cooperoides Perkins, 2014^{i c g}Hydraena copulata Perkins, 2011^{i c g}Hydraena cordata Schaufuss, 1883^{i c g}Hydraena cordiformis Jäch and Díaz, 2000^{i c g}Hydraena cordispina Perkins, 2011^{i c g}Hydraena corinna Orchymont, 1936^{i c g}Hydraena cornelli Jäch and Díaz, 1998^{i c g}Hydraena corrugis Orchymont, 1934^{i c g}Hydraena coryleti Jäch, 1992^{i c g}Hydraena costiniceps Perkins, 1980^{i c g}Hydraena crepidoptera Jäch, 1992^{i c g}Hydraena cristatigena Jäch and Díaz, 2000^{i c g}Hydraena croatica Kuwert, 1888^{i c g}Hydraena cryptostoma Jäch, 1992^{i c g}Hydraena crystallina Perkins, 1980^{i c g}Hydraena cubista Perkins, 2007^{i c g}Hydraena cultrata Perkins, 2007^{i c g}Hydraena cunicula Perkins, 2011^{i c g}Hydraena cunninghamensis Perkins, 2007^{i c g}Hydraena curta Kiesenwetter, 1849^{i c g}Hydraena curtipalpis Jäch and Díaz, 1998^{i c g}Hydraena curvipes Jäch and Díaz, 2012^{i c g}Hydraena curvosa Perkins, 2011^{i c g}Hydraena cuspidicollis Perkins, 1980^{i c g}Hydraena cyclops Jäch and Díaz, 2000^{i c g}Hydraena cygnus Zwick, 1977^{i c g}Hydraena czernohorskyi Müller, 1911^{i c g}Hydraena dalmatina Ganglbauer, 1901^{i c g}Hydraena damascena Pic, 1910^{i c g}Hydraena dariensis Perkins, 2011^{i c g}Hydraena darwini Perkins, 2007^{i c g}Hydraena d-concava Perkins, 2011^{i c g}Hydraena d-destina Perkins, 1980^{i c g}Hydraena debeckeri ^{i c g}Hydraena decepta Perkins, 2011^{i c g}Hydraena decipiens Zwick, 1977^{i c g}Hydraena decolor Sainte-Claire Deville, 1903^{i c g}Hydraena decui Spangler, 1980^{i c g}Hydraena delia Balfour-Browne, 1978^{i c g}Hydraena deliquesca Perkins, 2007^{i c g}Hydraena delvasi Delgado and Collantes, 1996^{i c g}Hydraena densa Fauvel, 1883^{i c g}Hydraena dentipalpis Reitter, 1888^{i c g}Hydraena dentipes Germar, 1824^{i c g}Hydraena devillei Ganglbauer, 1901^{i c g}Hydraena devincta Orchymont, 1940^{i c g}Hydraena diadema Perkins, 2011^{i c g}Hydraena diazi Trizzino, Jäch and Ribera in Trizzino, Jäch, Audisio and Rivera, 2011^{i c g}Hydraena diffusa Perkins, 2011^{i c g}Hydraena dilutipes Fairmaire, 1898^{i c g}Hydraena dimorpha Orchymont, 1922^{i c g}Hydraena dinarica Freitag & de Vries, 2021^{i c g}Hydraena dinosaurophila Jäch, 1994^{i c g}Hydraena discicollis Fairmaire, 1898^{i c g}Hydraena discreta Ganglbauer, 1904^{i c g}Hydraena disparamera Perkins, 2007^{i c g}Hydraena dochula Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena dolichogaster Janssens, 1965^{i c g}Hydraena dorrigoensis Perkins, 2007^{i c g}Hydraena draconisaurati Jäch and Díaz, 2005^{i c g}Hydraena dudgeoni Perkins, 2011^{i c g}Hydraena duodecimata Perkins, 2014^{i c g}Hydraena duohamata Perkins, 2011^{i c g}Hydraena ebriimadli Jäch, 1988^{i c g}Hydraena ecuadormica Perkins, 2011^{i c g}Hydraena egoni Jäch, 1986^{i c g}Hydraena eichleri Orchymont, 1937^{i c g}Hydraena einsteini Perkins, 2011^{i c g}Hydraena elephanta Perkins, 2014^{i c g}Hydraena elisabethae Jäch, 1992^{i c g}Hydraena eliya Jäch, 1982^{i c g}Hydraena emarginata Rey, 1885^{i c g}Hydraena emineae Jäch and Kasapoglu, 2006^{i c g}Hydraena epeirosi Ferro, 1985^{i c g}Hydraena errina Orchymont, 1948^{i c g}Hydraena erythraea Régimbart, 1905^{i c g}Hydraena eryx Orchymont, 1948^{i c g}Hydraena esquinita Brojer and Jäch, 2011^{i c g}Hydraena essentia Perkins, 2011^{i c g}Hydraena eucnemis Janssens, 1970^{i c g}Hydraena evanescens Rey, 1884^{i c g}Hydraena evansi Balfour-Browne, 1945^{i c g}Hydraena exarata Kiesenwetter, 1866^{i c g}Hydraena exasperata Orchymont, 1935^{i c g}Hydraena excisa Kiesenwetter, 1849^{i c g}Hydraena exhalista Perkins, 2011^{i c g}Hydraena exilipes Perkins, 1980^{i c g}Hydraena expedita Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena explanata Pic, 1905^{i c g}Hydraena extorris Zwick, 1977^{i c g}Hydraena falcata Jäch, 1992^{i c g}Hydraena farsensis Skale and Jäch, 2011^{i c g}Hydraena fasciata Perkins, 2011^{i c g}Hydraena fascinata Perkins, 2011^{i c g}Hydraena fasciola Perkins, 2011^{i c g}Hydraena fasciolata Perkins, 2011^{i c g}Hydraena fasciopaca Perkins, 2011^{i c g}Hydraena favulosa Perkins, 2014^{i c g}Hydraena fenestella Perkins, 2011^{i c g}Hydraena ferethula Perkins, 2007^{i c g}Hydraena feryi Skale and Jäch, 2011^{i c g}Hydraena feuerborni Orchymont, 1932^{i c g}Hydraena fijiensis Balfour-Browne, 1945^{i c g}Hydraena filum Sahlberg, 1908^{i c g}Hydraena finita Orchymont, 1943^{i c g}Hydraena finki Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena finniganensis Perkins, 2007^{i c g}Hydraena fiorii Porta, 1899^{i c g}Hydraena fischeri Schönmann, 1991^{i c g}Hydraena flagella Perkins, 2011^{i c g}Hydraena fluvicola ^{i c g}Hydraena foliobba Perkins, 2011^{i c g}Hydraena fontana Orchymont, 1932^{i c g}Hydraena fontiscarsavii ^{i c g}Hydraena formosapala Perkins, 2011^{i c g}Hydraena formula Orchymont, 1932^{i c g}Hydraena forticollis Perkins, 2007^{i c g}Hydraena fosterorum Trizzino, Jäch and Ribera in Trizzino, Jäch, Audisio and Rivera, 2011^{i c g}Hydraena franklyni Deler-Hernández and Delgado, 2012^{i c g}Hydraena freitagi Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena frenzeli Skale and Jäch, 2008^{i c g}Hydraena fritzi Jäch, 1992^{i c g}Hydraena frondsicola ^{i c g}Hydraena funda Perkins, 2011^{i c g}Hydraena fundacta Perkins, 2011^{i c g}Hydraena fundaequalis Perkins, 2007^{i c g}Hydraena fundapta Perkins, 2011^{i c g}Hydraena fundarca Perkins, 2011^{i c g}Hydraena fundata Perkins, 2007^{i c g}Hydraena fundextra Perkins, 2011^{i c g}Hydraena furthi Jäch, 1982^{i c g}Hydraena gaditana Lagar and Fresneda, 1990^{i c g}Hydraena galatica Janssens, 1970^{i c g}Hydraena galea Perkins, 2011^{i c g}Hydraena gavarrensis Jäch, Díaz and Martinoy, 2005^{i c g}Hydraena geminya Perkins, 1980^{i c g}Hydraena genumorpha Perkins, 2014^{i c g}Hydraena georgiadesi Orchymont, 1931^{i c g}Hydraena geraldneuhauseri Jäch and Díaz, 2006^{i c g}Hydraena germaini Orchymont, 1923^{i c g}Hydraena glassmani Jäch, 1986^{i c g}Hydraena gnatella Orchymont, 1945^{i c g}Hydraena gnatelloides Orchymont, 1945^{i c g}Hydraena gracilidelphis Trizzino, Valladares, Garrido and Audisio, 2012^{i c g}Hydraena gracilis Germar, 1824^{i c g}Hydraena graciloides ^{i c g}Hydraena grandis Reitter, 1885^{i c g}Hydraena graphica Orchymont, 1931^{i c g}Hydraena grata Orchymont, 1944^{i c g}Hydraena gregalis Orchymont, 1944^{i c g}Hydraena gressa Orchymont, 1944^{i c g}Hydraena griphus Orchymont, 1944^{i c g}Hydraena grouvellei Orchymont, 1923^{i c g}Hydraena grueberi Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena guadelupensis Orchymont, 1923^{i c g}Hydraena guangxiensis Jäch and Díaz, 2005^{i c g}Hydraena guatemala Perkins, 1980^{i c g}Hydraena guentheri Jäch, 1992^{i c g}Hydraena guilin Jäch and Díaz, 2005^{i c g}Hydraena gynaephila Jäch, 1997^{i c g}Hydraena habitiva Perkins, 2014^{i c g}Hydraena hainzi Jäch, 1988^{i c g}Hydraena haitensis Perkins, 1980^{i c g}Hydraena hajeki Skale and Jäch, 2011^{i c g}Hydraena hamifera Zwick, 1977^{i c g}Hydraena hansreuteri Jäch and Díaz, 2005^{i c g}Hydraena hayashii Jäch and Díaz, 2012^{i c g}Hydraena helena Orchymont, 1929^{i c g}Hydraena hendrichi Jäch, Díaz and Skale, 2013^{i c g}Hydraena hernandoi Fresneda and Lagar, 1990^{i c g}Hydraena herzogestella Perkins, 2011^{i c g}Hydraena heterogyna Bedel, 1898^{i c g}Hydraena hiekei Jäch, 1992^{i c g}Hydraena hillaryi Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena hintoni Perkins, 2011^{i c g}Hydraena hispanica Ganglbauer, 1901^{i c g}Hydraena holdhausi Pretner, 1929^{i c g}Hydraena hornabrooki Perkins, 2011^{i c g}Hydraena hortensis Jäch and Díaz, 2000^{i c g}Hydraena hosiwergi Freitag and Jäch, 2007^{i c g}Hydraena hosseinieorum Bilton and Jäch, 1998^{i c g}Hydraena huangshanensis Jäch and Díaz, 2005^{i c g}Hydraena huitongensis Jäch and Díaz, 2005^{i c g}Hydraena humanica Perkins, 2014^{i c g}Hydraena hunanensis Pu, 1951^{i c g}Hydraena hungarica Rey, 1884^{i c g}Hydraena huonica Perkins, 2011^{i c g}Hydraena hyalina Perkins, 1980^{i c g}Hydraena hynesi Zwick, 1977^{i c g}Hydraena hypipamee Perkins, 2007^{i c g}Hydraena ibalimi Perkins, 2011^{i c g}Hydraena iberica Orchymont, 1936^{i c g}Hydraena idema Perkins, 2011^{i c g}Hydraena iheya Jäch and Díaz, 1999^{i c g}Hydraena ilamensis Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena ilica Jäch, 1994^{i c g}Hydraena imbria Jäch and Díaz, 2001^{i c g}Hydraena impala Perkins, 2011^{i c g}Hydraena imperatrix Kniz, 1919^{i c g}Hydraena impercepta Zwick, 1977^{i c g}Hydraena impressicollis Fairmaire, 1898^{i c g}Hydraena inancala Perkins, 2007^{i c g}Hydraena inapicipalpis Pic, 1918^{i c g}Hydraena incisiva Perkins, 2011^{i c g}Hydraena incista Perkins, 2011^{i c g}Hydraena incurva Orchymont, 1932^{i c g}Hydraena indiana Jäch, 1994^{i c g}Hydraena indica Orchymont, 1920^{i c g}Hydraena infoveola Perkins, 2011^{i c g}Hydraena ingens ^{i c g}Hydraena inhalista Perkins, 2011^{i c g}Hydraena injectiva Perkins, 2014^{i c g}Hydraena innuda Perkins, 2007^{i c g}Hydraena inopinata Jäch and Díaz, 1998^{i c g}Hydraena inplacopaca Perkins, 2011^{i c g}Hydraena insandalia Perkins, 2011^{i c g}Hydraena insita Orchymont, 1932^{i c g}Hydraena insolita Orchymont, 1932^{i c g}Hydraena insularis Orchymont, 1945^{i c g}Hydraena integra Pretner, 1931^{i c g}Hydraena intensa Perkins, 2011^{i c g}Hydraena intermedia Rosenhauer, 1847^{i c g}Hydraena intraangulata Perkins, 2007^{i c g}Hydraena inusta Orchymont, 1932^{i c g}Hydraena invicta Perkins, 2007^{i c g}Hydraena iriomotensis Jäch and Díaz, 1999^{i c g}Hydraena isabelae Castro and Herrera, 2001^{i c g}Hydraena isolinae Jäch and Díaz, 1998^{i c g}Hydraena ispirensis Kasapoglu, Jäch and Skale, 2010^{i c g}Hydraena iterata Orchymont, 1948^{i c g}Hydraena jacobsoni Orchymont, 1932^{i c g}Hydraena jaechiana ^{i c g}Hydraena jaegeri Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena jailensis Breit, 1917^{i c g}Hydraena janczyki Jäch, 1992^{i c g}Hydraena janeceki Jäch, 1987^{i c g}Hydraena janssensi Nilsson, 2001^{i c g}Hydraena jengi Jäch and Díaz, 1998^{i c g}Hydraena jilanzhui Jäch and Díaz, 2005^{i c g}Hydraena jivaro Perkins, 1980^{i c g}Hydraena johncoltranei Perkins, 2011^{i c g}Hydraena jubilata Perkins, 2011^{i c g}Hydraena kadowakii Jäch and Díaz, 2012^{i c g}Hydraena kakadu Perkins, 2007^{i c g}Hydraena kamitei Jäch and Díaz, 2012^{i c g}Hydraena karinkukolae Jäch, 1989^{i c g}Hydraena karmai Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena kasyi Jäch, 1992^{i c g}Hydraena kaufmanni Ganglbauer, 1901^{i c g}Hydraena kellymilleri Perkins, 2011^{i c g}Hydraena khnzoriani Janssens, 1968^{i c g}Hydraena kilimandjarensis Régimbart, 1906^{i c g}Hydraena kitayamai Jäch and Díaz, 2012^{i c g}Hydraena knischi Orchymont, 1928^{i c g}Hydraena kocheri Berthélemy, 1992^{i c g}Hydraena kodadai Freitag and Jäch, 2007^{i c g}Hydraena koje Perkins, 2011^{i c g}Hydraena koma Perkins, 2011^{i c g}Hydraena krasnodarensis Jäch and Díaz, 2006^{i c g}Hydraena kroumiriana Kaddouri, 1992^{i c g}Hydraena kucinici Micetic Stankovic and Jäch, 2012^{i c g}Hydraena kuehnelti Jäch, 1989^{i c g}Hydraena kurdistanica Jäch, 1988^{i c g}Hydraena kwangsiensis Pu, 1951^{i c g}Hydraena labropaca Perkins, 2011^{i c g}Hydraena lagamba Brojer and Jäch, 2011^{i c g}Hydraena lapidicola Kiesenwetter, 1849^{i c g}Hydraena lapissectilis Jäch, 1992^{i c g}Hydraena larissae Jäch and Díaz, 2000^{i c g}Hydraena larsoni Perkins, 2007^{i c g}Hydraena lascrucensis Brojer and Jäch, 2011^{i c g}Hydraena lassulipes Perkins, 2011^{i c g}Hydraena latebricola Jäch, 1986^{i c g}Hydraena latisoror Perkins, 2007^{i c g}Hydraena lazica Janssens, 1963^{i c g}Hydraena leechi Perkins, 1980^{i c g}Hydraena leei Jäch and Díaz, 1998^{i c g}Hydraena legorskyi Jäch and Brojer, 2012^{i c g}Hydraena lehmanni Jäch and Díaz, 2005^{i c g}Hydraena leonhardi Breit, 1916^{i c g}Hydraena leprieuri Sainte-Claire Deville, 1905^{i c g}Hydraena levantina Sahlberg, 1908^{i c g}Hydraena ligulipes Jäch, 1988^{i c g}Hydraena lilianae Perkins, 2011^{i c g}Hydraena limbobesa Perkins, 2011^{i c g}Hydraena limpidicollis Perkins, 1980^{i c g}Hydraena liriope Orchymont, 1943^{i c g}Hydraena longicollis Sharp, 1882^{i c g}Hydraena loripes Perkins, 2011^{i c g}Hydraena lotti Bilton, 2013^{i c g}Hydraena lucasi Lagar, 1984^{i c g}Hydraena lucernae Zwick, 1977^{i c g}Hydraena ludovicae Orchymont, 1931^{i c g}Hydraena luminicollis Perkins, 2007^{i c g}Hydraena luridipennis MacLeay, 1873^{i c g}Hydraena lusitana ^{i c g}Hydraena lycia Jäch, 1988^{i c g}Hydraena macedonica Orchymont, 1931^{i c g}Hydraena maculicollis Champion, 1920^{i c g}Hydraena maculopala Perkins, 2011^{i c g}Hydraena madronensis Castor, García and Ferreras, 2000^{i c g}Hydraena magna Pu, 1951^{i c g}Hydraena magnessa Jäch, 1997^{i c g}Hydraena magnetica Zwick, 1977^{i c g}Hydraena mahensis Scott, 1913^{i c g}Hydraena malagricola Jäch and Díaz, 2012^{i c g}Hydraena malickyi Jäch, 1989^{i c g}Hydraena malkini Perkins, 1980^{i c g}Hydraena manabica Perkins, 2011^{i c g}Hydraena manaslu Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena manfredjaechi Delgado and Soler, 1991^{i c g}Hydraena manguao Freitag and Jäch, 2007^{i c g}Hydraena manulea Perkins, 2011^{i c g}Hydraena manuloides Perkins, 2011^{i c g}Hydraena marawaka Perkins, 2011^{i c g}Hydraena marcosae Aguilera, Hernando and Ribera, 1997^{i c g}Hydraena marginicollis Kiesenwetter, 1849^{i c g}Hydraena mariannae Jäch, 1992^{i c g}Hydraena marinae Castro, 2003^{i c g}Hydraena martensi Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena martinschoepfi Jäch and Díaz, 2005^{i c g}Hydraena masatakai Jäch and Díaz, 2003^{i c g}Hydraena maureenae Perkins, 1980^{i c g}Hydraena mauriciogarciai Perkins, 2011^{i c g}Hydraena mazamitla Perkins, 1980^{i c g}Hydraena mecai Millán and Aguilera, 2000^{i c g}Hydraena melas Dalla Torre, 1877^{i c g}Hydraena mercuriala Perkins, 2011^{i c g}Hydraena meschniggi Pretner, 1929^{i c g}Hydraena metzeni Perkins, 2007^{i c g}Hydraena mexicana Perkins, 1980^{i c g}Hydraena mianminica Perkins, 2011^{i c g}Hydraena michaelbalkei Jäch, Díaz and Skale, 2013^{i c g}Hydraena mignymixys Perkins, 1980^{i c g}Hydraena millerorum Perkins, 2007^{i c g}Hydraena miniretia Perkins, 2007^{i c g}Hydraena mintrita Perkins, 2011^{i c g}Hydraena mitchellensis Perkins, 2007^{i c g}Hydraena miyatakei Satô, 1959^{i c g}Hydraena modili Jäch, 1988^{i c g}Hydraena monikae Jäch and Díaz, 2000^{i c g}Hydraena monscassius Jäch, 1988^{i c g}Hydraena monstruosipes Ferro, 1986^{i c g}Hydraena monteithi Perkins, 2007^{i c g}Hydraena morio Kiesenwetter, 1849^{i c g}Hydraena motzfeldi Skale and Jäch, 2011^{i c g}Hydraena mouzaiensis Sainte-Claire Deville, 1909^{i c g}Hydraena mpumalanga Perkins, 2014^{i c g}Hydraena muelleri Pretner, 1931^{i c g}Hydraena muezziginea Jäch, 1988^{i c g}Hydraena multiloba Perkins, 2011^{i c g}Hydraena multimurata Perkins, 2014^{i c g}Hydraena multispina Perkins, 2011^{i c g}Hydraena mylasae Jäch, 1992^{i c g}Hydraena namibiensis Perkins, 2014^{i c g}Hydraena nanocolorata Perkins, 2011^{i c g}Hydraena nanopala Perkins, 2011^{i c g}Hydraena nanoscintilla Perkins, 2011^{i c g}Hydraena natiforma Perkins, 2014^{i c g}Hydraena neblina Perkins, 2011^{i c g}Hydraena nelsonmandelai Makhan, 2008^{i c g}Hydraena neoaccurata Perkins, 2014^{i c g}Hydraena nevermanni Perkins, 1980^{i c g}Hydraena newtoni Perkins, 1980^{i c g}Hydraena nielshaggei Freitag and Jäch, 2007^{i c g}Hydraena nigra Hatch, 1965^{i c g}Hydraena nigrita Germar, 1824^{i c g}Hydraena nike Jäch, 1995^{i c g}Hydraena nilguenae ^{i c g}Hydraena nitidimenta Perkins, 2011^{i c g}Hydraena nivalis Jäch, 1992^{i c g}Hydraena nomenipes Perkins, 2014^{i c g}Hydraena notsui Satô, 1978^{i c g}Hydraena novacula Perkins, 2011^{i c g}Hydraena numidica Sainte-Claire Deville, 1905^{i c g}Hydraena nurabadensis Skale and Jäch, 2011^{i c g}Hydraena nuratauensis Jäch, 1994^{i c g}Hydraena oaxaca Perkins, 1980^{i c g}Hydraena oblio Perkins, 1980^{i c g}Hydraena occidentalis Perkins, 1980^{i c g}Hydraena occitana ^{i c g}Hydraena okapa Perkins, 2011^{i c g}Hydraena okinawensis Jäch and Díaz, 1999^{i c g}Hydraena olidipastoris Jäch, 1988^{i c g}Hydraena ollopa Perkins, 2011^{i c g}Hydraena optica Jäch and Díaz, 2012^{i c g}Hydraena orchis Jäch and Díaz, 1998^{i c g}Hydraena orcula Perkins, 1980^{i c g}Hydraena ordishi Delgado and Palma, 1997^{i c g}Hydraena orientalis Breit, 1916^{i c g}Hydraena ortali Jäch, 1986^{i c g}Hydraena orthosia Jäch, Díaz and Dia in Jäch, Dia and Díaz, 2006^{i c g}Hydraena otiarca Perkins, 2011^{i c g}Hydraena ovata Janssens, 1961^{i c g}Hydraena owenobesa Perkins, 2011^{i c g}Hydraena oxiana Janssens, 1974^{i c g}Hydraena ozarkensis Perkins, 1980^{i c g}Hydraena pachyptera Apfelbeck, 1909^{i c g}Hydraena pacifica Perkins, 1980^{i c g}Hydraena pacificica Perkins, 2011^{i c g}Hydraena paeminosa Perkins, 1980^{i c g}Hydraena pagaluensis Hernando and Ribera, 2001^{i c g}Hydraena paganettii Ganglbauer, 1901^{i c g}Hydraena pajarita Brojer and Jäch, 2011^{i c g}Hydraena pakistanica Jäch, 1992^{i c g}Hydraena pala Perkins, 2011^{i c g}Hydraena palamita Perkins, 2011^{i c g}Hydraena palawanensis Freitag and Jäch, 2007^{i c g}Hydraena pallidula Sainte-Claire Deville, 1909^{i c g}Hydraena palustris Erichson, 1837^{i c g}Hydraena pamirica Jäch, 1992^{i c g}Hydraena pamphylia Jäch and Díaz, 2001^{i c g}Hydraena pangaei Jäch, 1992^{i c g}Hydraena pantanalensis Perkins, 2011^{i c g}Hydraena paraguayensis Janssens, 1972^{i c g}Hydraena parciplumea Perkins, 2007^{i c g}Hydraena particeps Perkins, 1980^{i c g}Hydraena parva Zwick, 1977^{i c g}Hydraena parysatis Janssens, 1981^{i c g}Hydraena paucistriata Jäch and Díaz, 2000^{i c g}Hydraena paulmoritz Jäch, Díaz and Skale, 2013^{i c g}Hydraena pavicula Perkins, 1980^{i c g}Hydraena paxillipes Perkins, 2011^{i c g}Hydraena peckorum Perkins, 2011^{i c g}Hydraena pectenata Perkins, 2011^{i c g}Hydraena pedroaguilerai Perkins, 2011^{i c g}Hydraena pegopyga Perkins, 2011^{i c g}Hydraena pelops Jäch, 1995^{i c g}Hydraena pennsylvanica Kiesenwetter, 1849^bHydraena pensylvanica Kiesenwetter, 1849^{i c g}Hydraena penultimata Perkins, 2011^{i c g}Hydraena perkinsi Spangler, 1980^{i c g}Hydraena perlonga Balfour-Browne, 1950^{i c g}Hydraena perpunctata Perkins, 2011^{i c g}Hydraena persica Janssens, 1981^{i c g}Hydraena pertransversa Perkins, 2011^{i c g}Hydraena peru Perkins, 1980^{i c g}Hydraena pesici Skale and Jäch, 2011^{i c g}Hydraena petila Perkins, 1980^{i c g}Hydraena phainops Perkins, 2011^{i c g}Hydraena phallerata Orchymont, 1944^{i c g}Hydraena phallica Orchymont, 1930^{i c g}Hydraena phassilyi Orchymont, 1931^{i c g}Hydraena philippi Jäch and Díaz, 2005^{i c g}Hydraena philyra Orchymont, 1944^{i c g}Hydraena phoenicia Jäch, Díaz and Dia in Jäch, Dia and Díaz, 2006^{i c g}Hydraena photogenica Perkins, 2011^{i c g}Hydraena pici Sainte-Claire Deville, 1905^{i c g}Hydraena picula Perkins, 2011^{i c g}Hydraena pilimera Brojer and Jäch, 2011^{i c g}Hydraena pilipes Zwick, 1977^{i c g}Hydraena pilulambra Perkins, 2011^{i c g}Hydraena pindica Janssens, 1965^{i c g}Hydraena pisciforma Perkins, 2014^{i c g}Hydraena planata Kiesenwetter, 1849^{i c g}Hydraena plastica Orchymont, 1943^{i c g}Hydraena platycnemis Jäch, 1988^{i c g}Hydraena platynaspis Jäch, 1988^{i c g}Hydraena platysoma Janssens, 1968^{i c g}Hydraena plaumanni Orchymont, 1937^{i c g}Hydraena plumipes Rey, 1886^{i c g}Hydraena pluralticola Perkins, 2011^{i c g}Hydraena plurifurcata Jäch and Díaz, 1998^{i c g}Hydraena polita Kiesenwetter, 1849^{i c g}Hydraena pontequula Perkins, 1980^{i c g}Hydraena pontica Janssens, 1963^{i c g}Hydraena porchi Perkins, 2007^{i c g}Hydraena porcula Jäch and Díaz, 1998^{i c g}Hydraena praetermissa Jäch, 1987^{i c g}Hydraena premordica Perkins, 1980^{i c g}Hydraena pretneri Chiesa, 1927^{i c g}Hydraena prieto Perkins, 1980^{i c g}Hydraena princeps Fauvel, 1903^{i c g}Hydraena processa Perkins, 2011^{i c g}Hydraena producta Mulsant and Rey, 1852^{i c g}Hydraena proesei Skale and Jäch, 2011^{i c g}Hydraena profunda Perkins, 2014^{i c g}Hydraena prokini Jäch and Díaz, 2006^{i c g}Hydraena propria Perkins, 2011^{i c g}Hydraena prusensis Jäch, 1992^{i c g}Hydraena pseudocirrata Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena pseudopalawanensis Freitag and Jäch, 2007^{i c g}Hydraena pseudoriparia Orchymont, 1945^{i c g}Hydraena puetzi Jäch, 1994^{i c g}Hydraena pugillista Perkins, 2007^{i c g}Hydraena pulchella Germar, 1824^{i c g}Hydraena pulsatrix Perkins, 1980^{i c g}Hydraena punctata LeConte, 1855^{i c g}Hydraena puncticollis Sharp, 1882^{i c g}Hydraena punctilata Perkins, 2011^{i c g}Hydraena putearius Jäch and Díaz, 2000^{i c g}Hydraena pygmaea Waterhouse, 1833^{i c g}Hydraena quadrata ^{i c g}Hydraena quadricollis Wollaston, 1864^{i c g}Hydraena quadricurvipes Perkins, 1980^{i c g}Hydraena quadriplumipes Perkins, 2011^{i c g}Hydraena quechua Perkins, 1980^{i c g}Hydraena queenslandica Perkins, 2007^{i c g}Hydraena quetiae Castro, 2000^{i c g}Hydraena quilisi Lagar, Fresneda and Fernando, 1987^{i c g}Hydraena quintana Perkins, 2011^{i c g}Hydraena ramuensis Perkins, 2011^{i c g}Hydraena ramuquintana Perez, 2011^{i c g}Hydraena receptiva Perkins, 2011^{i c g}Hydraena reflectiva Perkins, 2014^{i c g}Hydraena regimbarti Zaitzev, 1908^{i c g}Hydraena remulipes Perkins, 2011^{i c g}Hydraena reticulata Zwick, 1977^{i c g}Hydraena reticuloides Perkins, 2007^{i c g}Hydraena reticulositis Perkins, 2007^{i c g}Hydraena revelovela Perkins, 2007^{i c g}Hydraena reverberata Perkins, 2011^{i c g}Hydraena reyi Kuwert, 1888^{i c g}Hydraena rhinoceros ^{i c g}Hydraena rhodia Jäch, 1985^{i c g}Hydraena riberai Jäch, Aguilera and Hernando, 1998^{i c g}Hydraena richardimbi Jäch, 1992^{i c g}Hydraena rigua Orchymont, 1931^{i c g}Hydraena ripaeaureae ^{i c g}Hydraena riparia Kugelann, 1794^{i c g}Hydraena rivularis Guillebeau, 1896^{i c g}Hydraena robusta Zwick, 1977^{i c g}Hydraena rosannae Audisio, Trizzino and De Biase in Audisio, Trizzino, De Biase, Mancini and Antonini, 2009^{i c g}Hydraena rudallensis Blackburn, 1896^{i c g}Hydraena rufipennis Boscá Berga, 1932^{i c g}Hydraena rufipes Curtis, 1830^{i c g}Hydraena rugosa Mulsant, 1844^{i c g}Hydraena ruinosa Zwick, 1977^{i c g}Hydraena rukiyeae Kasapoglu, Jäch and Skale, 2010^{i c g}Hydraena sabella Perkins, 1980^{i c g}Hydraena saga Orchymont, 1930^{i c g}Hydraena sagatai Perkins, 2011^{i c g}Hydraena sahlbergi Orchymont, 1923^{i c g}Hydraena saluta Perkins, 2011^{i c g}Hydraena samia Jäch, 1986^{i c g}Hydraena samnitica Knisch, 1924^{i c g}Hydraena sanagergelyae Brojer and Jäch, 2011^{i c g}Hydraena sanfilippoi ^{i c g}Hydraena sappho Janssens, 1965^{i c g}Hydraena sardoa Binaghi, 1961^{i c g}Hydraena satoi Jäch and Díaz, 1999^{i c g}Hydraena sautakei Jäch and Díaz, 1999^{i c g}Hydraena sauteri Orchymont, 1913^{i c g}Hydraena scabra Orchymont, 1925^{i c g}Hydraena scabrosa Orchymont, 1931^{i c g}Hydraena schawalleri Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena schilfii Jäch, 1988^{i c g}Hydraena schillhammeri Jäch, 1988^{i c g}Hydraena schmidi Jäch and Díaz, 2001^{i c g}Hydraena schoedli Jäch, 1992^{i c g}Hydraena schoenmanni Jäch, 1988^{i c g}Hydraena schubertorum Jäch and Díaz, 2001^{i c g}Hydraena schuelkei Jäch, 1992^{i c g}Hydraena schuleri Ganglbauer, 1901^{i c g}Hydraena scintilla Perkins, 1980^{i c g}Hydraena scintillabella Perkins, 1980^{i c g}Hydraena scintillamima Perkins, 2011^{i c g}Hydraena scintillapicta Perkins, 2011^{i c g}Hydraena scintillarca Perkins, 2011^{i c g}Hydraena scintillutea Perkins, 1980^{i c g}Hydraena scitula Orchymont, 1943^{i c g}Hydraena scolops Perkins, 1980^{i c g}Hydraena scopula Perkins, 1980^{i c g}Hydraena scythica Janssens, 1974^{i c g}Hydraena sebastiani Perkins, 2014^{i c g}Hydraena sepikramuensis Perkins, 2011^{i c g}Hydraena septemlacuum Jäch, 1992^{i c g}Hydraena serpentina Jäch, 1988^{i c g}Hydraena serricollis Wollaston, 1864^{i c g}Hydraena servilia Orchymont, 1936^{i c g}Hydraena sexarcuata Perkins, 2011^{i c g}Hydraena sexsuprema Perkins, 2011^{i c g}Hydraena sharmai Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena sharpi Rey, 1886^{i c g}Hydraena shorti Perkins, 2011^{i c g}Hydraena sicula Kiesenwetter, 1849^{i c g}Hydraena sidon Jäch, Díaz and Dia in Jäch, Dia and Díaz, 2006^{i c g}Hydraena sierra Perkins, 1980^{i c g}Hydraena similis Orchymont, 1930^{i c g}Hydraena simonidea Orchymont, 1931^{i c g}Hydraena simplicicollis Blackburn, 1896^{i c g}Hydraena simplipes Zwick, 1977^{i c g}Hydraena singaporensis Jäch, Díaz and Skale, 2013^{i c g}Hydraena sinope Jäch, 1992^{i c g}Hydraena smyrnensis Sahlberg, 1908^{i c g}Hydraena socius Jäch and Díaz, 1999^{i c g}Hydraena solarii Pretner, 1930^{i c g}Hydraena solodovnikovi Jäch and Díaz, 2006^{i c g}Hydraena sordida Sharp, 1882^{i c g}Hydraena spangleri Perkins, 1980^{i c g}Hydraena spatula Perkins, 2011^{i c g}Hydraena speciosa Orchymont, 1944^{i c g}Hydraena spinipes Baudi, 1882^{i c g}Hydraena spinissima Perkins, 2007^{i c g}Hydraena spinobesa Perkins, 2011^{i c g}Hydraena splecoma Perkins, 1980^{i c g}Hydraena squalida Orchymont, 1932^{i c g}Hydraena stefani Jäch and Díaz, 2005^{i c g}Hydraena steineri Perkins, 2011^{i c g}Hydraena stellula Perkins, 2011^{i c g}Hydraena storeyi Perkins, 2007^{i c g}Hydraena striolata Perkins, 2011^{i c g}Hydraena stussineri Kuwert, 1888^{i c g}Hydraena subacuminata Rey, 1884^{i c g}Hydraena subgrandis Jäch, 1988^{i c g}Hydraena subimpressa Rey, 1885^{i c g}Hydraena subina Orchymont, 1944^{i c g}Hydraena subinflata Orchymont, 1944^{i c g}Hydraena subinoides Orchymont, 1944^{i c g}Hydraena subintegra Ganglbauer, 1901^{i c g}Hydraena subinura Orchymont, 1944^{i c g}Hydraena subirregularis Pic, 1918^{i c g}Hydraena subjuncta Orchymont, 1930^{i c g}Hydraena sublamina Orchymont, 1945^{i c g}Hydraena sublapsa Orchymont, 1945^{i c g}Hydraena subsequens Rey, 1886^{i c g}Hydraena supersexa Perkins, 2011^{i c g}Hydraena supina Perkins, 2011^{i c g}Hydraena szechuanensis Pu, 1951^{i c g}Hydraena takin Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena takutu Perkins, 2011^{i c g}Hydraena tarsotricha Perkins, 2011^{i c g}Hydraena tarvisina ^{i c g}Hydraena tatii Sáinz-Cantero and Alba-Tercedor, 1989^{i c g}Hydraena tauricola Jäch, 1988^{i c g}Hydraena taxila Janssens, 1962^{i c g}Hydraena tekmanensis Jäch, Skale and Kasapoglu, 2011^{i c g}Hydraena tenjikuana Satô, 1979^{i c g}Hydraena tenuis ^{i c g}Hydraena tenuisella Perkins, 2007^{i c g}Hydraena tenuisoror Perkins, 2007^{i c g}Hydraena terebrans Jäch, 1992^{i c g}Hydraena terralta Perkins, 1980^{i c g}Hydraena testacea Curtis, 1830^{i c g}Hydraena tetana Perkins, 2011^{i c g}Hydraena textila Perkins, 2007^{i c g}Hydraena thienemanni Orchymont, 1932^{i c g}Hydraena thola Perkins, 2011^{i c g}Hydraena tholasoris Perkins, 2011^{i c g}Hydraena thumbelina Perkins, 2011^{i c g}Hydraena thumbelipes Perkins, 2011^{i c g}Hydraena thyene Balfour-Browne, 1958^{i c g}Hydraena tiara Perkins, 2014^{i c g}Hydraena tibiopaca Perkins, 2011^{i c g}Hydraena tobogan Perkins, 2011^{i c g}Hydraena torosopala Perkins, 2011^{i c g}Hydraena torricellica Perkins, 2011^{i c g}Hydraena transvallis Perkins, 2011^{i c g}Hydraena trapezoidalis Zwick, 1977^{i c g}Hydraena tricantha Zwick, 1977^{i c g}Hydraena trichotarsa Perkins, 2011^{i c g}Hydraena tricosipes Perkins, 2011^{i c g}Hydraena tridigita Perkins, 2011^{i c g}Hydraena tridisca Perkins, 2007^{i c g}Hydraena triloba Perkins, 2007^{i c g}Hydraena trinidensis Perkins, 1980^{i c g}Hydraena triparamera Jäch, 1982^{i c g}Hydraena tritropis Perkins, 2011^{i c g}Hydraena tritutela Perkins, 2011^{i c g}Hydraena truncata Rey, 1885^{i c g}Hydraena tsushimaensis Jäch and Díaz, 2012^{i c g}Hydraena tubuliphallis Jäch, 1982^{i c g}Hydraena tucumanica Perkins, 1980^{i c g}Hydraena tuolumne Perkins, 1980^{i c g}Hydraena turcica Janssens, 1965^{i c g}Hydraena turrialba Perkins, 1980^{i c g}Hydraena tyrrhena Binaghi, 1961^{i c g}Hydraena ulna Perkins, 2011^{i c g}Hydraena umbolenta Perkins, 2011^{i c g}Hydraena unca Valladares, 1989^{i c g}Hydraena undevigintioctogintasisyphos Jäch and Díaz, 2005^{i c g}Hydraena undulata Jäch and Díaz, 1998^{i c g}Hydraena uniforma Perkins, 2014^{i c g}Hydraena unita Perkins, 2011^{i c g}Hydraena uzbekistanica Jäch, 1994^{i c g}Hydraena vadosa Perkins, 2014^{i c g}Hydraena valentini Jäch and Díaz, 2012^{i c g}Hydraena vandykei Orchymont, 1923^{i c g}Hydraena variopaca Perkins, 2011^{i c g}Hydraena vedrasi Orchymont, 1931^{i c g}Hydraena vela Perkins, 1980^{i c g}Hydraena velvetina Perkins, 2011^{i c g}Hydraena venezuela Perkins, 2011^{i c g}Hydraena verberans Jäch and Díaz, 2006^{i c g}Hydraena verstraeteni Ferro, 1984^{i c g}Hydraena victoriae Jäch and Díaz, 1999^{i c g}Hydraena vietnamensis ^{i c g}Hydraena virginalis Janssens, 1963^{i c g}Hydraena vodozi Sainte-Claire Deville, 1908^{i c g}Hydraena vulgaris Jäch and Díaz, 2000^{i c g}Hydraena waldheimi Jäch, 1987^{i c g}Hydraena wangi Jäch and Díaz, 1998^{i c g}Hydraena wangmiaoi Jäch and Díaz, 2005^{i c g}Hydraena watanabei Jäch and Satô, 1988^{i c g}Hydraena wattsi Perkins, 2007^{i c g}Hydraena weigeli Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena weiri Perkins, 2007^{i c g}Hydraena wencke Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena wewalkai Jäch, 1988^{i c g}Hydraena williamsensis Deane, 1931^{i c g}Hydraena wittmeri Satô, 1979^{i c g}Hydraena wolfi Skale and Jäch in Jäch and Skale, 2009^{i c g}Hydraena wrasei Jäch, 1992^{i c g}Hydraena xingu Perkins, 2011^{i c g}Hydraena yangae Jäch, Díaz and Skale, 2013^{i c g}Hydraena yonaguniensis Jäch and Díaz, 2003^{i c g}Hydraena yosemitensis Perkins, 1980^{i c g}Hydraena yoshitomii Jäch and Díaz, 1999^{i c g}Hydraena youngi Perkins, 1980^{i c g}Hydraena ypsilon Zwick, 1977^{i c g}Hydraena yunnanensis Pu, 1942^{i c g}Hydraena zapatina Perkins, 1980^{i c g}Hydraena zelandica Ordish, 1984^{i c g}Hydraena zetteli Freitag and Jäch, 2007^{i c g}Hydraena zezerensis Díaz Pazos and Bilton, 1995^{i c g}Hydraena zimbabwensis Perkins, 2014^{i c g}Hydraena zwicki Perkins, 2007^{i c g}
Data sources: i = ITIS, c = Catalogue of Life, g = GBIF, b = Bugguide.net