Hydrophilidae, also called water scavenger beetles, is a family of chiefly aquatic beetles. Aquatic hydrophilids are notable for their long maxillary palps, which are longer than their antennae. Several of the former subfamilies of Hydrophilidae have recently been removed and elevated to family rank; Epimetopidae, Georissidae (= Georyssinae), Helophoridae, Hydrochidae, and Spercheidae (= Sphaeridiinae). Some of these formerly-included groups are primarily terrestrial or semi-aquatic.
The vernacular name water scavenger beetles is not an accurate description of their habit. With rare exceptions, the larvae are predatory while the adults may be vegetarians or predators in addition to scavenging. Many species are able to produce sounds.
Species of Hydrophilus are reported as pests in fish hatcheries. Other species are voracious consumers of mosquito larvae, and have potential as biological control agents. There are 2,835 species in 169 genera 
Berosus is a genus of beetles in the family Hydrophilidae, the water scavenger beetles. The genus contains 273 species. It is distributed worldwide.Beetles of this genus are aquatic, with most living in ponds and other marshy habitat types.Cercyon (beetle)
Cercyon is a genus of water scavenger beetles in the family Hydrophilidae. There are at least 50 described species in Cercyon.Cymbiodyta
Cymbiodyta is a genus of hydrophilid beetles with 31 species. Twenty–eight of the species occur in the Americas and three species in the Palearctic.Enochrus
Enochrus, a genus of water scavenger beetles, is the third-largest genus of hydrophilids with 222 species in six subgenera worldwide.Georissus
Georissus, also called minute mud-loving beetles, is the only genus in the beetle family Georissidae (or Georyssidae). They are tiny insects living in wet soil, often near water. Found on every continent except Antarctica.Haliplidae
The Haliplidae are a family of water beetles who swim using an alternating motion of the legs. They are therefore clumsy in water (compared e.g. with the Dytiscidae or Hydrophilidae), and prefer to get around by crawling. The family consists of about 200 species in 5 genera, distributed wherever there is freshwater habitat; it is the only extant member of superfamily Haliploidea. They are also known as crawling water beetles or haliplids.Helochares
Helochares is a genus of hydrophilid beetles with over 180 species in five subgenera worldwide.Helophorus
Helophorus ís the only genus in the beetle family Helophoridae (traditionally included within Hydrophilidae as the subfamily Helophorinae). They are small insects, found mainly in the Holarctic region (150 occur in Palearctic and 41 species in North America), but two or three species also live in the Afrotropical region, Central America and one in the Indomalayan region (northern India).Hydrobius
Hydrobius is a genus of hydrophilid beetles that contains nine species distributed throughout the Holarctic ecozone.
Hydrobius arcticus Kuwert, 1890
Hydrobius convexus Brullé, 1835
Hydrobius fuscipes (Linnaeus, 1758)
Hydrobius melaenus (Germar, 1824)
Hydrobius orientalis Jia & Short, 2009
Hydrobius pauper Sharp, 1884
Hydrobius pui Jia, 1995
Hydrobius punctistriatus Jia, 1995
Hydrobius tumidus LeConte, 1835Hydrobius fuscipes
Hydrobius fuscipes is a species of beetles in the family Hydrophilidae that is found across much of the temperate Northern Hemisphere.Hydrochara
Hydrochara is a genus of hydrophilid beetles with 23 species in North America, Europe, Asia, and Africa.Hydrophilinae
Hydrophilinae is the largest subfamily of Hydrophilidae that contains 1852 species in 61 genera and 8 tribes.Hydrophilini
Hydrophilini is a tribe in the subfamily Hydrophilinae of aquatic beetles that contains 198 species in 8 genera.Hydrophiloidea
Hydrophiloidea is a superfamily of beetles. Until recently it was only a single family, the water scavenger beetles (Hydrophilidae), but several of the subfamilies have been removed and raised to family rank.
The present list of recognized families is thus:
Georissidae (= Georyssidae)
Spercheidae (= Sphaeridiidae)The Histeroidea seem to be very closely related and may be part of an extended Hydrophiloidea clade; some researchers have proposed merging the two superfamilies into one.Hydrophilus (beetle)
Hydrophilus is a genus of beetles in the family Hydrophilidae, the water scavenger beetles. There are about 48 species in three subgenera in the genus: Hydrophilus, Dibolocelus, and Temnopterus.Laccobius
Laccobius is a genus of water scavenger beetles in the family Hydrophilidae. There are at least 70 described species in Laccobius.Megasternini
Megasternini is a tribe of water scavenger beetles in the family Hydrophilidae. There are at least 70 described species in Megasternini.Sphaeridiinae
Sphaeridiinae is a subfamily of water scavenger beetles (insects in the family Hydrophilidae). Some species live in fresh water as both larvae and adults.Tropisternus
Tropisternus is a genus of hydrophilid beetles with 63 species in five subgenera in North and South America.
Extant Coleoptera families