The Dytiscidae – based on the Greek dytikos (δυτικός), "able to dive" – are the predaceous diving beetles, a family of water beetles. They occur in virtually any freshwater habitat around the world, but a few species live among leaf litter. The adults of most are between 1 and 2.5 cm (0.4–1.0 in) long, though much variation is seen between species. The European Dytiscus latissimus and Brazilian Megadytes ducalis are the largest, reaching up to 4.5 cm (1.8 in) and 4.75 cm (1.9 in) respectively. In contrast, the smallest is likely the Australian Limbodessus atypicali of subterranean waters, which only is about 0.9 mm (0.035 in) long. Most are dark brown, blackish, or dark olive in color with golden highlights in some subfamilies. The larvae are commonly known as water tigers due to their voracious appetite. They have short, but sharp mandibles and immediately upon biting, they deliver digestive enzymes into prey to suck their liquefied remains. The family includes more than 4,000 described species in numerous genera.
Acilius is a holarctic genus of diving beetles in the family Dytiscidae and typically has a life cycle that is univoltine.
The Barstow Formation is a series of limestones, conglomerates, sandstones, siltstones and shales exposed in the Mojave Desert near Barstow in San Bernardino County, California.
Schistomerus is an extinct genus of predaceous diving beetle that is known from one species, Schistomerus californense, which inhabited Lake Barstow during the middle Miocene. It is the most common beetle found in the concretions from the Barstow Formation. The specimens are typically preserved in three dimensions.
Hydrodytes is a genus of predaceous diving beetles in the family Dytiscidae. There are at least three described species in Hydrodytes. It is found in North America and the Neotropics.
Stygoporus oregonensis is a species of beetle in the family Dytiscidae, the only species in the genus Stygoporus.
Hydroporinae is a subfamily of predaceous diving beetles in the family Dytiscidae. There are at least 2,200 described species in Hydroporinae.
Eretes sticticus, the western erete, is a species of predaceous diving beetle in the family Dytiscidae. It is found in Africa, the Middle East, and the Americas from the southern United States to Peru. This species preys specifically on mosquito larvae in ponds and pools. They can kill up to all the instar larvae of the mosquito depending on size and density of the prey.
Hyphydrini is a tribe of predaceous diving beetles in the family Dytiscidae. There are about 16 genera and more than 390 described species in Hyphydrini.
Acilius semisulcatus is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America.
Acilius sylvanus is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America.
Acilius abbreviatus is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America.
Derovatellus floridanus is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America.
Hydrodytes dodgei is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America.
Amurodytes is a genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Amurodytes, A. belovi, found in the Palearctic.
Ereboporus is a genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Ereboporus, E. naturaconservatus, found in North America.
Hyphoporus nilghiricus, is a species of predaceous diving beetle found in India, Pakistan, and Sri Lanka. Sometimes, the species is included into the genus Hygrotus by some authors.
Hydrovatus picipennis, is a species of predaceous diving beetle found in India, Sri Lanka, Indonesia, Philippines, China and Thailand.
Hydrovatus lyratus, is a species of predaceous diving beetle widespread in South Asia, South East Asia and Australian region.
Neonectes is a genus of beetles in the family Dytiscidae, containing three species found in the Palaerctic, including China, Japan, the Korean Peninsula, and Russia:
