The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface.
Silphidae is a family of beetles that are known commonly as large carrion beetles, carrion beetles or burying beetles. There are two subfamilies: Silphinae and Nicrophorinae. Nicrophorines are sometimes known as sexton beetles. The number of species is relatively small at around two hundred. They are more diverse in the temperate region although a few tropical endemics are known. Both subfamilies feed on decaying organic matter such as dead animals. The subfamilies differ in which uses parental care and which types of carcasses they prefer. Silphidae are considered to be of importance to forensic entomologists because when they are found on a decaying body they are used to help estimate a post-mortem interval.
The Trachypachidae are a family of beetles that generally resemble small ground beetles, but that are distinguished by the large coxae of their rearmost legs. There are only six known extant species in the family, with four species of Trachypachus found in northern Eurasia and northern North America, and two species of Systolosoma in Chile and Argentina. They were much more diverse in the past, with dozens of described species from the Mesozoic.
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.
Histeridae is a family of beetles commonly known as clown beetles or hister beetles. This very diverse group of beetles contains 3,900 species found worldwide. They can be easily identified by their shortened elytra that leaves two of the seven tergites exposed, and their geniculate (elbowed) antennae with clubbed ends. These predatory feeders are most active at night and will fake death if they feel threatened. This family of beetles will occupy almost any kind of niche throughout the world. Hister beetles have proved useful during forensic investigations to help in time of death estimation. Also, certain species are used in the control of livestock pests that infest dung and to control houseflies. Because they are predacious and will even eat other hister beetles, they must be isolated when collected.
Staphylinoidea is a superfamily of beetles. It is a very large and diverse group with worldwide distribution.
The Fanniidae are a small group of true flies largely confined to the Holarctic and temperate Neotropical realms; there are 11 Afrotropical species, 29 Oriental, and 14 Australasian.
Cleridae are a family of beetles of the superfamily Cleroidea. They are commonly known as checkered beetles. The family Cleridae has a worldwide distribution, and a variety of habitats and feeding preferences.
Leiodidae is a family of beetles with around 3800 described species found worldwide. Members of this family are commonly called round fungus beetles due to the globular shape of many species, although some are more elongated in shape. They are generally small or very small beetles and many species have clubbed antennae.
Cryptorhynchinae is a large subfamily of weevils (Curculionidae), with some 6000 species. They are found in most zoogeographic regions although they are most diverse in the Neotropics, Australia and Oceania.
Histeroidea is a superfamily of beetles in the infraorder Staphyliniformia.
The Perissommatidae are a family of flies (Diptera) that was proposed in 1962 by Donald Colless based on the species Perissomma fusca from Australia. The family now includes five extant species within the single genus Perissomma, four from Australia and one from Chile. The Perissommatidae are unusual as they appear to have four compound eyes. They have a small slender body less than 2 mm in length. Their wings are large in comparison to their bodies and subsequently their flight is weak. Preferring high-altitude forest environments, adults only fly in the winter. The larvae live in decaying leaf litter in wet sclerophyll or cool rain forests. Some species are suspected to be associated with fungi. In the case of Perissomma macalpinei, numbers of adults have been observed congregating in clumps of foliage and rising in short, zigzag flights in the sunlight above the foliage for short periods before descending.
Helophorus ís the only genus in the beetle family Helophoridae within the Hydrophiloidea. They are small insects, found mainly in the Holarctic region, but two or three species also live in the Afrotropical region, Central America and one in the Indomalayan region.
Chlaenius is a large and diverse genus of ground beetle. It is native to the Palearctic realm, Afrotropical realm, and Nearctic realm. Worldwide, roughly 1,000 species are currently recognized with the majority of known species occurring in the Oriental and Afrotropical regions. The genus is divided into many subgenera.
Silvanidae, "silvan flat bark beetles", is a family of beetles in the superfamily Cucujoidea, consisting of 68 described genera and about 500 described species. The family is represented on all continents except Antarctica, and is most diverse at both the generic and species levels in the Old World tropics.
Monotomidae is a family of beetles in the superfamily Cucujoidea. The family is found worldwide, with approximately 240 species in 33 genera. The ecological habits of the family are diverse, with different members of the group being found under tree bark, in decaying vegetation, on flowers and in ant nests. Their ecology is obscure, while at least some species are mycophagous, feeding on the fruiting bodies of ascomycete fungi, Rhyzophagus are predators on bark beetles and possibly Phoridae larvae, with the larvae of some species also being mycophagous.
Agyrtinae is a subfamily in the family Agyrtidae. It contains four genera: Agyrtes, Ecanus, Ipelates and Lyrosoma.
Eulichadidae is a family of beetles belonging to Elateriformia. There are two extant genera, Eulichas with several dozen species native to the Indomalayan realm of Asia, and Stenocolus, with a single species native to Western North America. The larvae are aquatic, with the larvae of Eulichas being found in sandy sediments of clean forest streams, while the larvae of Stenocolus are found under rocks and in leaf packs in low elevation streams and rivers. They are herbivious/saprophagous with larval specimens of Eulichas having been found with wood particles in their stomachs, while the larvae of Stenocolus are known to feed on decaying roots and detritus. The adults are terrestrial, with specimens of Eulichas typically found using light, while specimens of Stenocolus are typically found in riparian vegetation, and are not attracted to light. Potential extinct genera have been described from Mesozoic rocks, but the placement of several of these taxa in the family is disputed.
Lyrosoma opacum is a species of primitive carrion beetle in the family Agyrtidae. It is found in Europe and Northern Asia and North America.
Ipelates is a genus of primitive carrion beetles in the family Agyrtidae. There are at least four described species in Ipelates.
