Holarctic
Guides
Badister
Badister is a genus of small ground beetles in the family Carabidae, comprising approximately 54 species distributed across North Africa, the Near East, and the Holarctic. Members of this genus are characterized by asymmetric mandibles adapted for shell-breaking predation on gastropods. The genus is classified within the tribe Licinini, a group widely associated with snail-eating behavior. Badister species occupy wetland and riparian habitats, with documented activity in wet grasslands, lakeshores, and riverbanks.
Baryphyma trifrons
Threefront Dwarf Weaver
Baryphyma trifrons is a dwarf spider (family Linyphiidae) with a Holarctic distribution spanning North America, Europe, the Caucasus, and across Russia to the Far East. The species was first described by O. Pickard-Cambridge in 1863. Two subspecies are recognized: B. t. trifrons and B. t. affine. It is one of approximately 4,600 species in Linyphiidae, the second-largest spider family.
Basalys
Basalys is a genus of minute parasitoid wasps in the family Diapriidae. Members are among the smallest known insects, with some species measuring less than 0.5 mm in body length. These wasps are internal parasitoids of dipteran larvae, particularly those developing in decaying organic matter. The genus has a Holarctic distribution with confirmed records from Scandinavia and other northern European regions.
Bathyphantes
dwarf spiders, sheetweb weavers
Bathyphantes is a genus of dwarf spiders (family Linyphiidae) comprising approximately 57 species distributed across the Holarctic region, with additional species in South America, Africa, Asia, and Oceania. These small spiders construct sheet webs and are characterized by complex male pedipalps and female epigyna used for species identification. The genus was first described by Anton Menge in 1866. At least one species, Bathyphantes simillimus, exhibits a triennial life cycle potentially adapted to cooler environments.
Bathytrichina
Bathytrichina is a subtribe of ichneumon wasps within the tribe Tryphonini. It comprises small to medium-sized parasitoid wasps that attack sawfly larvae. The group is relatively small and poorly studied, with limited published information on its biology and species composition.
Behningiidae
Sand-burrowing Mayflies, Tuskless Burrowing Mayflies
Behningiidae is a small, primitive family of burrowing mayflies with four described genera: three extant (Behningia, Dolania, Protobehningia) and one fossil (†Archaeobehningia). Nymphs inhabit sandy river sediments but lack the tusk-like mandibular projections typical of other burrowing mayfly families. The family has a Holarctic distribution, with Dolania occurring in North America and the remaining genera in northern Europe and Asia. Members are rarely collected due to their subterranean lifestyle.
Bembidion alaskense
Bembidion alaskense is a ground beetle species in the family Carabidae, described by Carl Lindroth in 1962. The species has a Holarctic distribution, with records from Alaska and Russia. It belongs to the large genus Bembidion, which comprises numerous small, often riparian-associated beetles. The species name reflects its Alaskan type locality.
Bembidion arcticum
Bembidion arcticum is a species of ground beetle in the family Carabidae, described by Lindroth in 1963. It is distributed across the Holarctic region, with records from Alaska, Canada, Russia, and the United States. The species is among the many small carabid beetles in the large genus Bembidion, which are generally predatory insects. Very few observational records exist for this species, with only one observation documented on iNaturalist.
Bembidion bruxellense
Bembidion bruxellense is a species of ground beetle in the family Carabidae, first described by Wesmael in 1835. It is native to Europe and has been recorded from North America (Canada and USA), suggesting either a native Holarctic distribution or possible introduction. The species belongs to the large genus Bembidion, which contains over 1,200 described species of small to medium-sized predatory beetles.
Bembidion compressum
Bembidion compressum is a small ground beetle in the family Carabidae, described by Lindroth in 1963. The species has a Holarctic distribution, occurring across northern regions of Europe, Asia, and North America. Like other members of the genus Bembidion, it is a predatory beetle inhabiting ground-level environments.
Bembidion grapii
Bembidion grapii is a Holarctic species of ground beetle in the family Carabidae, first described by Gyllenhal in 1827. It occurs across northern regions of Europe, Asia, and North America. The species belongs to the large genus Bembidion, which comprises numerous small, often metallic ground beetles.
Bembidion immaturum
Bembidion immaturum is a species of ground beetle in the family Carabidae, first described by Carl Lindroth in 1954. It is a small carabid beetle distributed across northern North America, extending into Russia. The species belongs to the large genus Bembidion, which contains hundreds of species of small ground beetles commonly found in moist habitats.
Bembidion incrematum
Bembidion incrematum is a small ground beetle in the family Carabidae, first described by John Lawrence LeConte in 1860. It is a member of the large genus Bembidion, which comprises numerous species of small predatory beetles commonly found in diverse terrestrial habitats. The species has a Holarctic distribution, occurring across northern regions of North America and Eurasia. Like other Bembidion species, it is presumed to be a ground-dwelling predator, though specific ecological studies are limited.
Bembidion lapponicum
Bembidion lapponicum is a species of ground beetle in the family Carabidae with a Holarctic distribution. It occurs across northern regions of Europe, Asia, and North America. The species was first described by Thomson in 1857 and is classified within the subgenus Bracteon of the large genus Bembidion.
Bembidion mckinleyi
Bembidion mckinleyi is a species of ground beetle in the family Carabidae, first described by Fall in 1926. It is a member of the large genus Bembidion, which contains over 1,400 described species of small to medium-sized carabid beetles. The species is known from both North America and Europe, with three recognized subspecies: B. m. mckinleyi, B. m. carneum, and B. m. scandicum. Like other members of its genus, it is likely associated with moist habitats near water bodies.
Bembidion scopulinum
Bembidion scopulinum is a Holarctic species of ground beetle in the family Carabidae. It occurs across Europe, Northern Asia, temperate Asia, and North America including Alaska and Canada. The species was described by William Kirby in 1837. Two subspecies are recognized: B. s. scopulinum and B. s. bellulum.
Bembidion semipunctatum
Bembidion semipunctatum is a small ground beetle species in the family Carabidae. It occurs across the Holarctic region, with documented presence in North America and Europe. The species was first described by Graells in 1858. Records indicate it has been collected in locations including Alaska, Austria, and the Azores (Terceira).
Bembidion stephensii
A ground beetle species in the family Carabidae with a Holarctic distribution spanning North America and Europe. First described by Crotch in 1866, it belongs to the large genus Bembidion, which contains numerous species of small predatory beetles commonly found in moist habitats.
Bembidion sulcipenne
Bembidion sulcipenne is a ground beetle in the family Carabidae. The species was described by J. Sahlberg in 1880. It occurs across a broad Holarctic range spanning Europe, Northern Asia (excluding China), and North America. Three subspecies are recognized: B. s. sulcipenne, B. s. hyperboroides, and B. s. prasinoides.
Beridinae
soldier flies
Beridinae is a subfamily of soldier flies (Stratiomyidae) comprising approximately 15 genera. Species in this subfamily have been documented across temperate regions including Canada, Alaska, and Iran, with records indicating presence in forested habitats. The subfamily is taxonomically well-defined with available identification keys for adults and larvae.
Bibio brunnipes
Bibio brunnipes is a march fly in the family Bibionidae with a Holarctic distribution, occurring across northern regions of both the Old and New Worlds. The species has been subject to taxonomic revision, with several previously described species now synonymized under B. brunnipes. Like other members of the genus, adults are typically active in spring and may occur in large aggregations. Larval stages develop in soil and contribute to decomposition processes.
Bibio holtii
Bibio holtii is a species of March fly described by McAtee in 1922. It belongs to the family Bibionidae, a group characterized by males with large holoptic eyes and females with small heads relative to body size. The species exhibits a Holarctic distribution pattern, occurring across the northern hemisphere. Like other Bibio species, adults are typically active in spring and form conspicuous swarms.
Bibio siebkei
Bibio siebkei is a Holarctic species of March fly in the family Bibionidae. It occurs across both the Palearctic and Nearctic regions, with synonyms including Bibio labradorensis and Bibio monstri now synonymized with this species. Like other Bibio species, adults are likely to be encountered in spring when males form swarming aggregations. Larval stages develop in soil where they feed on decaying organic matter.
Bibiocephala
net-winged midges
Bibiocephala is a genus of net-winged midges in the family Blephariceridae, established by Osten Sacken in 1874. The genus contains five described species distributed across the Holarctic region. These midges are members of a specialized family whose larvae inhabit fast-flowing streams and rivers. Adult Bibiocephala are characterized by their distinctive wing venation with dense, net-like crossveins that give the family its common name.
Bistonini
Bistonini is a tribe of geometer moths within the subfamily Ennominae. Members are characterized by relatively large size and hairy bodies compared to other geometrids, with some species resembling tiger moths (Arctiidae) in appearance. The tribe occupies a basal position within the broader Boarmiini group and retains more ancestral morphological traits. Taxonomic boundaries remain fluid, with some treatments merging Bistonini into an expanded Boarmiini or including the Erannini.
Blastodacna
Blastodacna is a genus of small moths in the family Elachistidae, first described by Wocke in 1876. The genus contains approximately 15 recognized species distributed primarily across the Holarctic region, with the majority of species occurring in the Palearctic. Taxonomic placement of this genus has been disputed, with some authorities historically assigning it to Agonoxenidae or recognizing it as the separate family Blastodacnidae. The genus includes several species associated with fruit trees, notably Blastodacna pyrigalla, which is known as a pest of pear.
Blethisa
Blethisa is a genus of ground beetles in the family Carabidae, subfamily Elaphrinae. It comprises approximately nine extant species distributed across the Holarctic region, plus one fossil species from the Pleistocene. Members of this genus are associated with aquatic or semi-aquatic habitats, with documented diving behavior in at least one species.
Blondelia
Blondelia is a genus of tachinid flies established by Robineau-Desvoidy in 1830, currently comprising approximately 20 described species. As members of the tribe Blondeliini, these flies are parasitoids, with larvae developing inside other insects. The genus has been recorded across the Holarctic region, with species distributed in Europe and North America.
Boletina
fungus gnats
Boletina is a species-rich genus of fungus gnats in the family Mycetophilidae, characterized by a mainly Holarctic distribution. The genus has historically been taxonomically challenging due to morphological similarities among species and paraphyletic relationships with related genera including Aglaomyia, Coelosia, and Gnoriste. Recent molecular phylogenetic studies and taxonomic revisions have clarified some relationships, though the genus remains under active investigation. Boletina species are particularly diverse in northern Europe, where ongoing research continues to reveal new species.
Bolitocharina
Bolitocharina is a subtribe of rove beetles (Staphylinidae) within the tribe Homalotini, subfamily Aleocharinae. It was established by Carl Gustaf Thomson in 1859. The subtribe contains multiple genera of small to minute beetles characterized by compact body forms and reduced elytra typical of the family. Members are found primarily in the Holarctic region, with some representation in other biogeographic zones.
Boloria chariclea
Arctic fritillary, purplish fritillary
Boloria chariclea is a Holarctic butterfly in the family Nymphalidae, known as the Arctic fritillary or purplish fritillary. It inhabits cold northern environments including tundra, taiga, alpine meadows, and acid bogs. The species exhibits a two-year life cycle in some populations, with larvae hibernating during first and second winters. Multiple subspecies are recognized across its broad range, including the endemic B. c. montinus isolated in the White Mountains of New Hampshire for approximately 9,000 years.
Boloria chariclea butleri
Butler's Fritillary
Boloria chariclea butleri is a subspecies of fritillary butterfly in the family Nymphalidae, commonly known as Butler's Fritillary. It belongs to a genus of butterflies typically associated with northern and montane habitats. The species Boloria chariclea has a Holarctic distribution, with subspecies butleri occurring in North America. Like other Boloria species, it is likely associated with moist meadow and tundra-edge habitats where larval host plants in the Violaceae family occur.
Boloria eunomia
Bog Fritillary, Ocellate Bog Fritillary
Boloria eunomia is a circumboreal fritillary butterfly distributed across the Holarctic in tundra, forest-tundra, and open acid bog habitats. Adults are orange-brown with distinctive round silver spots on the hindwing underside, a key diagnostic feature. The species exhibits ecotypic variation: meadow populations feed primarily on Polygonum bistorta, while bog populations utilize Ericaceae including Vaccinium species. It is univoltine with adults flying from late May through July depending on latitude. The species is considered vulnerable in parts of its range due to habitat loss from drainage, recreational development, and climate change.
Bombus flavidus
Yellowish Cuckoo Bumble Bee, Yellowish Cuckoo Bumblebee
Bombus flavidus is a widespread Holarctic cuckoo bumble bee and one of the most broadly distributed bumble bee species globally. As a social parasite, it invades colonies of other bumble bee species rather than building its own nests. Recent taxonomic research has clarified its status, synonymizing the former North American Bombus fernaldae with B. flavidus while recognizing an eastern North American subspecies, B. flavidus appalachiensis.
Bombylius curtirhynchus
Bombylius curtirhynchus is a species of bee fly in the family Bombyliidae, first described by Evenhuis in 1978. The genus Bombylius comprises approximately 350 species distributed across the Holarctic region, with many species exhibiting the characteristic fuzzy appearance and hovering flight behavior typical of bee flies. Species in this genus are generally spring-active and possess elongated mouthparts adapted for nectar feeding.
Boreaphilus henningianus
Boreaphilus henningianus is a rove beetle (Staphylinidae) with a Holarctic distribution spanning northern Eurasia and North America. The species is associated with cold, northern habitats and has been recorded from boreal and subarctic regions. It belongs to the tribe Coryphiini within the subfamily Omaliinae.
Boreoheptagyia
Boreoheptagyia is a genus of non-biting midges in the subfamily Diamesinae of the family Chironomidae. The genus was established by Brundin in 1966 and currently comprises approximately 19 described species distributed across the Holarctic region, with particular concentration in mountainous areas of Europe and Asia. Species in this genus are associated with cold, well-oxygenated lotic habitats and exhibit limited dispersal capacity, resulting in restricted, often isolated geographic ranges.
Brachylomia
Minor Shoulder-knot (B. viminalis)
Brachylomia is a genus of small noctuid moths in the tribe Xylenini, containing approximately 17 described species. The genus occurs across the Holarctic region, with species distributed in North America, Europe, and Asia. Brachylomia viminalis, the Minor Shoulder-knot, is the best-known species and serves as the primary reference for understanding the genus. Most species are associated with damp habitats and willow-dominated vegetation.
Brachyopa
Sapeaters
Brachyopa is a Holarctic genus of hoverflies (Syrphidae) characterized by atypical grey and brown coloration that distinguishes them from the typically bright-colored members of their family. These flies are cryptic and easily overlooked among other dipteran families. Larvae develop under bark of dead wood in association with decaying sap, making the genus saproxylic. Adults have been observed feeding on sap flows from wounded trees.
Brachypalpus
Catkin Flies
Brachypalpus is a genus of hoverflies (Syrphidae) commonly known as catkin flies. Adults are distinguished by their triangular head that projects forward and downward, and males possess a spur on the hind trochanter. The genus comprises approximately 15 described species distributed primarily across the Holarctic region. Larvae develop in decaying wood and sap flows under tree bark.
Brillia
Brillia is a genus of non-biting midges in the subfamily Orthocladiinae of the family Chironomidae. The genus exhibits remarkable cryptic diversity, with DNA barcoding studies revealing 30 Barcode Index Numbers and 158 unique haplotypes across 13 described species. East Asian and North American populations show complete genetic distinctness, suggesting long-term isolation. The larvae inhabit freshwater depositional zones and serve as sensitive bioindicators for ecosystem monitoring.
Bromius obscurus
Western Grape Rootworm, Brown and Black Beetle
Bromius obscurus is a small leaf beetle (Chrysomelidae: Eumolpinae) and the sole member of its genus. It is a Holarctic species with a notable geographic parthenogenesis pattern: North American populations reproduce sexually while European populations are triploid and reproduce asexually. The species is recognized as a pest of grape vines in Europe and western North America. Adults possess a stridulatory apparatus on the wings, the first documented in the subfamily Eumolpinae.
Broscodera
Broscodera is a genus of ground beetles in the family Carabidae, established by Lindroth in 1961. The genus comprises at least four described species distributed across East Asia and western North America. Members of this genus belong to the subfamily Broscinae, a group of predominantly nocturnal beetles often associated with moist habitats. The genus shows a disjunct distribution pattern, with species occurring in China, Nepal, and the Pacific Northwest of North America.
Bryotropha similis
obscure neb
Bryotropha similis is a small gelechiid moth with a Holarctic distribution spanning northern Europe, Greenland, Iceland, and the Palaearctic region. The species has a wingspan of 11–13 mm and exhibits distinctive wing patterning with dark fuscous forewings and faint pale markings. Adults are active from early June to late August, likely in a single annual generation. The species is known from the iNaturalist community as the 'obscure neb'.
Byrsopages villosus
Byrsopages villosus is a species of weevil in the family Curculionidae, subfamily Entiminae, described by Boheman in 1842. The genus Byrsopages belongs to the tribe Byrsopagini, a group of broad-nosed weevils. Distribution records indicate presence in the Holarctic region, specifically Alaska and Kamchatka. Very little detailed biological information is available for this species.
Byturidae
fruitworms, fruitworm beetles
Byturidae is a small family of cleroid beetles comprising over 15 described species in two subfamilies. The family is primarily distributed in the Holarctic region and Southeast Asia. Larvae of some genera, particularly Byturus, are significant agricultural pests of Rubus fruits (raspberries and blackberries), while others feed on catkins. Adults feed on developing leaves, flowers, and pollen. The family includes two subfamilies: Platydascillinae (Southeast Asia) and Byturinae (Holarctic).
Caenoscelis ferruginea
Caenoscelis ferruginea is a species of silken fungus beetle in the family Cryptophagidae. It is distributed across the Holarctic region, with records from Europe, Northern Asia (excluding China), and North America. As a member of Cryptophagidae, it is associated with fungal habitats, though specific ecological details for this species remain poorly documented.
Caliadurgus
Caliadurgus is a genus of medium-sized spider wasps in the family Pompilidae, subfamily Pepsinae. The genus was established by Pate in 1946 as a replacement for the preoccupied name Calicurgus. These wasps are known for hunting orb-weaving spiders (Araneidae) and long-jawed orb weavers (Tetragnathidae) to provision nests for their larvae. The genus has a Holarctic and Neotropical distribution, with species recorded across North America, Europe, and South America.
Calitys scabra
Calitys scabra is a species of beetle in the family Trogossitidae, originally described by Thunberg in 1784 under the basionym Hispa scabra. It belongs to a small family of predatory beetles commonly known as bark-gnawing beetles. The species has a Holarctic distribution with confirmed records from several Canadian provinces.
Callobius
tangled nest spiders
Callobius is a genus of cribellate spiders in the family Amaurobiidae, commonly known as tangled nest spiders. The genus was established by R.V. Chamberlin in 1947 and contains 35 species with a Holarctic distribution spanning North America and Eurasia. Members of this genus construct characteristic tangled, lacy webs that issue from a retreat, often in crevices or holes. They are frequently confused with other cribellate spiders such as Kukulcania (Filistatidae) due to similar web architecture.