Holarctic
Guides
Exechiopsis
fungus gnats
Exechiopsis is a genus of fungus gnats in the family Mycetophilidae, established by Tuomikoski in 1966. The genus contains approximately 80 described species distributed across the Holarctic region, with particular diversity in Europe and Asia. Several species were formerly placed in the genus Xenexechia, which is now treated as a synonym. Species identification relies primarily on male genitalia morphology.
Exochus nigripalpis
Exochus nigripalpis is a species of ichneumon wasp described by Thomson in 1887. It belongs to the large family Ichneumonidae, which comprises parasitoid wasps that attack other insects. The species has been documented in Canada and parts of Europe, with observations concentrated in boreal and temperate regions. Like other members of the genus Exochus, it likely functions as a koinobiont parasitoid of Lepidopteran larvae, though specific host records for this species remain limited.
Exochus nigripalpis tectulum
Exochus nigripalpis tectulum is a subspecies of ichneumonid wasp described by Townes & Townes in 1959. It belongs to the genus Exochus, a group of koinobiont parasitoid wasps that attack concealed lepidopteran larvae. The subspecies designation suggests geographic or morphological differentiation from the nominate form E. nigripalpis nigripalpis. Records indicate presence in Canada, Denmark, and Norway.
Exyston variatum
Exyston variatum is a species of parasitoid wasp in the family Ichneumonidae, subfamily Ctenopelmatinae. The genus Exyston is recognized for its distinctive morphological features within this subfamily. As with other ctenopelmatines, this species is presumed to be a parasitoid of sawfly larvae (Hymenoptera: Symphyta), though direct host records for this specific species are limited in available literature. The species was described in the 19th century and is part of a genus distributed primarily in the Holarctic region.
Farula
Farula is a genus of caddisflies in the family Uenoidae, established by Milne in 1936. The genus belongs to the subfamily Uenoinae and is part of the Limnephiloidea superfamily. As a uenoid genus, Farula likely comprises small to medium-sized caddisflies associated with freshwater habitats. The genus has not been extensively documented in public observation databases.
Fenusa
Fenusa is a genus of common sawflies in the family Tenthredinidae containing approximately 11 described species. Species in this genus are specialized leaf miners whose larvae feed internally within leaves of host trees. Several species are significant economic pests, including the birch leafminer (F. pusilla), elm leafminer (F. ulmi), and European alder leafminer (F. dohrnii). The genus has been extensively studied in biological control contexts due to the damage caused by larval feeding.
Fenusella populifoliella
Fenusella populifoliella is a species of sawfly in the family Tenthredinidae. It is associated with Populus (poplar) species as a leaf miner. The species is part of a genus whose larvae create distinctive feeding patterns on host leaves.
Formicoxenus hirticornis
Dogwood Guest Ant
Formicoxenus hirticornis is a small myrmicine ant species in the genus Formicoxenus, commonly known as the Dogwood Guest Ant. Species in this genus are specialized social parasites that inhabit nests of larger host ant species, particularly those in the genus Myrmica. The specific epithet 'hirticornis' refers to hairy antennae. This species is rarely encountered and poorly documented in scientific literature.
Furcula
prominent moths
Furcula is a genus of moths in the family Notodontidae, subfamily Cerurinae. The genus contains multiple species distributed across the Holarctic region. Adults are nocturnal and attracted to light. Larvae are known for their distinctive forked posterior structure, which gives the genus its name (Latin for 'little fork').
Gammarus
scuds, freshwater shrimp, sideswimmers
Gammarus is a genus of amphipod crustaceans in the family Gammaridae, containing over 200 described species and representing one of the most species-rich crustacean genera. Species occupy diverse aquatic habitats ranging from purely freshwater to estuarine and marine environments, with salinity tolerance varying markedly among species. The genus is widely distributed throughout the Holarctic region, with additional species extending into tropical Southeast Asia. Gammarus species serve important ecological functions as shredders and predators in aquatic food webs.
Gargara genistae
Gargara genistae is a small treehopper in the family Membracidae, subfamily Centrotinae, characterized by a prominent backward-projecting pronotum and dark brown coloration. The species is oligophagous, feeding exclusively on phloem sap of shrubby Fabaceae including brooms and related genera. It is widely distributed across the Holarctic, Ethiopian, and Oriental regions, with occasional records in North America as an apparent introduction. Males produce species-specific substrate-borne calling signals used for mate recognition; cryptic species within this group are distinguished by acoustic rather than morphological characters.
Gastrodes
dirt-colored seed bugs
Gastrodes is a genus of dirt-colored seed bugs in the family Rhyparochromidae, established by Westwood in 1840. The genus contains approximately 14-15 described species distributed across Europe, temperate Asia, and North America. These true bugs belong to the tribe Drymini within the subfamily Rhyparochrominae.
Gaurotes
Gaurotes is a genus of longhorn beetles in the family Cerambycidae, subfamily Lepturinae. The genus contains approximately 25 described species distributed across the Holarctic region, with notable diversity in East Asia and North America. Species are typically small to medium-sized beetles with metallic coloration. The genus was established by LeConte in 1850 and includes several subgenera: Carilia, Gaurotes (sensu stricto), and Paragaurotes.
Gehringiinae
Gehringiinae is a small subfamily of ground beetles (Carabidae) containing approximately 20 described species across two genera: Gehringia and Zuphioides. Members are minute to small beetles, generally less than 3 mm in length, adapted to specialized microhabitats. The subfamily was established to accommodate taxa with distinctive morphological features that separate them from other carabid lineages. They are among the smallest carabid beetles and are rarely encountered due to their cryptic habits.
Gelechiidae
twirler moths, gelechiid moths
Gelechiidae is a large family of small moths, commonly known as twirler moths, that serves as the namesake family for the superfamily Gelechioidea. The family contains over 4,500 described species across more than 900 genera, with particularly high diversity in North America. Members are characterized by their small size, narrow fringed wings, and larvae that typically feed internally on host plant tissues. Many species are significant agricultural pests, while others have been employed for biological control of invasive plants.
Geomyza
frit flies
Geomyza is a genus of frit flies in the family Opomyzidae, comprising at least 30 described species. The genus includes economically significant agricultural pests, notably Geomyza tripunctata, whose larvae feed internally on grasses and cereals, killing the central shoot. These flies are distributed across the Holarctic region, with documented occurrences in Europe and North America. Larvae serve as hosts for hymenopterous parasitoids in grassland ecosystems.
Geophilus
Compost Centipedes
Geophilus is a large genus of soil centipedes in the family Geophilidae, with approximately 140 species. The genus has a Holarctic distribution and exhibits considerable morphological diversity, with body lengths ranging from under 1 cm to over 7 cm and leg pair counts varying from 29 to 89. Several species have adapted to specialized habitats, including deep cave environments. The genus is characterized by distinctive structural features of the head, forcipules, and trunk segments.
Gesneria centuriella
Smoky Gesneria
Gesneria centuriella is a small moth in the family Crambidae with a broad Holarctic distribution spanning Europe, Asia, and North America. The species exhibits considerable geographic variation, with five recognized subspecies adapted to different regions from Eurasia through Alaska to Greenland and the western United States. Adults are active in mid-summer, with North American populations flying from mid-June to July.
Gillmeria pallidactyla
Yarrow Plume Moth
Gillmeria pallidactyla, commonly known as the Yarrow Plume Moth, is a plume moth in the family Pterophoridae. It has a Holarctic distribution across North America and Eurasia. Adults are active from June to August, hiding in low vegetation during daylight hours and becoming active at dusk. The larvae are stem borers that overwinter in roots and feed on Achillea species in spring.
Glaucopsyche
blues, silvery blues, green-underside blues, black-eyed blues
Glaucopsyche is a genus of small butterflies commonly called 'blues' in the family Lycaenidae. The genus has a Holarctic distribution, with most species occurring in Palearctic Asia and several species in North America. It includes approximately 30 described species, among them the extinct Xerces blue (G. xerces), last seen in the early 1940s on the San Francisco Peninsula. Several species have notable conservation status, including the federally endangered Palos Verdes blue (G. lygdamus palosverdesensis).
Globia
arches
Globia is a genus of noctuid moths commonly called "arches", containing approximately seven described species. The genus was established in 2010 to replace the preoccupied name Capsula, which itself had replaced Archanara. Species in this genus are distributed across the Holarctic region. Several species have undergone notable range expansions in recent decades, particularly in Britain.
Glyphesis
dwarf spiders
Glyphesis is a genus of dwarf spiders (Linyphiidae) established by Eugène Louis Simon in 1926. The genus contains seven described species distributed across North America, Europe, and Asia. Several species are considered rare, with limited known localities. The genus is taxonomically stable and accepted in major arachnological databases.
Glyphicnemis
Glyphicnemis is a small genus of parasitoid wasps in the family Ichneumonidae, with 13 described species. The genus occurs in the Holarctic and Indo-Malaysian regions. Members are parasitoids, meaning they develop by feeding on or within host organisms.
Gnaphosa borea
Gnaphosa borea is a ground spider species in the family Gnaphosidae with a Holarctic distribution. The species is found in boreal forest habitats across northern Eurasia and North America. It has been documented in Russia (Tuva, South Siberia), Alaska, Maine, and several Canadian provinces including Alberta, Saskatchewan, and Yukon. The species appears to be associated with post-fire conditions in boreal forests and is rarely collected in harvest-origin forest stands.
Gnaphosa muscorum
Moss Ground Hunter
Gnaphosa muscorum is a ground spider species in the family Gnaphosidae, characterized by its Holarctic distribution spanning North America, Europe, and northern Asia. The species was first described by Ludwig Carl Christian Koch in 1866. A recognized subspecies, G. muscorum gaunitzi, occurs in Sweden and Russia. As a member of the ground spider family, it is presumed to be an active hunter rather than a web-builder, though specific behavioral details remain poorly documented.
Gnaphosa orites
Gnaphosa orites is a ground spider in the family Gnaphosidae with the broadest latitudinal distribution of any species in its genus, ranging from 43° to 70°N across the Holarctic region. The species was first described by Chamberlin in 1922 and has since been recorded from northern Europe, Scandinavia, the Caucasus, and across Russia from Europe to the Far East, as well as North America. A 2011 study documented its southernmost record in the Russian Far East, extending the known range of this cold-adapted species.
Gnathacmaeops pratensis
Gnathacmaeops pratensis is a species of long-horned beetle in the subfamily Lepturinae. It has a broad Holarctic distribution spanning Europe, Asia, and North America. The adult beetle is known to feed on Norway spruce (Picea abies). Two varieties have been described: var. obscuripennis Pic, 1901 and var. suturalis (Mulsant, 1863).
Gnorimoschema
Gnorimoschema is a genus of small moths in the family Gelechiidae, first described by Busck in 1900. The genus belongs to the tribe Gnorimoschemini and contains numerous species distributed across the Holarctic region, with particularly diverse faunas in North America and the Palaearctic. Several species are notable for their specialized life histories, including gall induction on host plants. The genus has been subject to extensive taxonomic revision, with many new species described in recent decades by researchers including Povolný and Powell.
Gnoristinae
fungus gnats
Gnoristinae is a subfamily of fungus gnats within the family Mycetophilidae. As of 2019, over 442 species have been described across more than 30 genera, making it one of the most taxonomically challenging groups in Mycetophilidae with species and generic boundaries subject to frequent revision. The subfamily has been characterized as highly diverse with new taxa described annually from various parts of the world. Members are generally small flies, with some species reaching only 3 mm in body length.
Goeridae
Armour-ballast Caddisflies
Goeridae is a family of caddisflies (Trichoptera) comprising approximately 12 genera and at least 160 described species. Larvae are primarily lotic, inhabiting streams and rivers, with some species occupying madicolous habitats such as wet cliff faces. The family is distinguished by larval case construction incorporating ballast stones for weight and stability. Adults exhibit highly modified male genitalia and maxillary palps in some species. Goeridae has a Holarctic distribution with records from North America, Europe, and Asia.
Gorytes
sand wasps
Gorytes is a genus of sand wasps in the family Crabronidae, comprising at least 70 described species distributed across the Holarctic region. These solitary wasps are ground-nesting predators that provision their burrows with paralyzed prey, primarily leafhoppers (Cicadellidae), for their developing larvae. The genus is taxonomically placed within the subtribe Gorytina of the tribe Bembicini.
Graphoderus
Graphoderus is a genus of predaceous diving beetles in the family Dytiscidae, comprising 12 extant species and 2 extinct species known from fossils. The genus is native to the Holarctic region, with species distributed across Europe, North America, and parts of Asia. Several species are of conservation concern, particularly G. bilineatus, which is listed in Annexes II and IV of the European Habitats Directive and has experienced significant population declines across its range.
Graphoderus perplexus
predacious diving beetle
Graphoderus perplexus is a predaceous diving beetle in the family Dytiscidae, described by Sharp in 1882. It is distributed across the Holarctic region, occurring in both North America and the Palearctic. Like other members of its genus, it is an aquatic predator inhabiting freshwater environments. The species is part of the tribe Aciliini, which includes other medium to large diving beetles.
Grylloblattidae
ice crawlers, icebugs, rock-crawlers
Grylloblattidae, commonly known as ice crawlers or icebugs, is a family of wingless, cold-adapted insects representing the sole living family of the order Grylloblattodea. These relict insects inhabit extreme cold environments including glacier margins, alpine snowfields, caves, and subalpine forests across disjunct regions of the Holarctic. With approximately 35 extant species in six genera, they exhibit narrow physiological temperature tolerances and are considered endangered due to climate warming and habitat specificity.
Gyrinus minutus
whirligig beetle
Gyrinus minutus is a small whirligig beetle with a Holarctic distribution spanning northern North America and Eurasia. It is distinguished from congeners by its weak swimming ability, solitary behavior among emergent vegetation, and near-absence of volatile defensive compounds. The species exhibits a shortened life cycle of approximately seven weeks from egg to adult and is capable of flight, allowing colonization of new water bodies throughout the summer.
Gyrophaena affinis
Gyrophaena affinis is a species of rove beetle in the family Staphylinidae. It is native to Europe and has been recorded across much of the Northern Hemisphere including Asia and North America. The species belongs to a genus known for small body size and association with fungal fruiting bodies.
Hahnia glacialis
Hahnia glacialis is a species of dwarf sheet spider in the family Hahniidae, first described by Sørensen in 1898. It is among the smallest members of its family, with adult body lengths under 4 millimeters. The species has a Holarctic distribution, occurring in cold-adapted regions of northern North America and Eurasia. Like other hahniids, it possesses the distinctive comb-like arrangement of spinnerets that gives the family its common name.
Halictoxenos
Halictoxenos is a genus of strepsipteran insects (twisted-wing parasites) in the family Stylopidae. The genus comprises approximately 23 species distributed across Asia, Europe, Africa, and the Americas, with a primarily Holarctic distribution. All species are obligate endoparasites of bees in the family Halictidae, particularly the subfamily Halictinae. The genus was established by W. Dwight Pierce in 1909.
Halictus
Furrow Bees, Sweat Bees
Halictus is a large genus of sweat bees in the family Halictidae, containing over 200 species divided among 15 subgenera. The genus is primarily distributed in the Northern Hemisphere, with most species exhibiting black or dark brown coloration, often with apical whitish abdominal bands. Many species are eusocial, forming colonies ranging from small groups of 2-4 individuals to over 200 bees, though social organization varies with environmental conditions. Nests are excavated in soil, with females constructing ovoid brood cells provisioned with pollen and nectar.
Halictus rubicundus
Orange-legged Furrow Bee
Halictus rubicundus, the orange-legged furrow bee, is a ground-nesting sweat bee with one of the widest natural distributions of any bee species, occurring throughout temperate regions of the Holarctic. The species is notable for its socially polymorphic behavior: populations are eusocial in warmer, lower-elevation regions with longer growing seasons, producing multiple broods with worker offspring, while populations at higher latitudes or elevations are solitary, producing only a single brood. This environmental plasticity in social organization has made the species a key model for studying the evolution of social behavior. Females excavate burrows in soil, typically on south-facing slopes to maximize thermal conditions for larval development.
Haliplus fulvus
Haliplus fulvus is a species of crawling water beetle in the family Haliplidae, widely distributed across Europe and North America. Adults are small beetles measuring 3.8–4.2 mm in length. The species is associated with aquatic habitats and has a holarctic distribution pattern.
Hammerschmidtia
Hammerschmidtia is a Holarctic genus of hoverflies (Diptera: Syrphidae) in the tribe Brachyopini. Larvae develop in sap under the bark of freshly fallen trees, particularly decaying aspen (Populus tremula). The genus includes five described species, with H. ferruginea being endangered in parts of its range due to habitat loss.
Haplodrassus signifer
Ensign Ground Hunter
Haplodrassus signifer is a species of ground spider in the family Gnaphosidae. It has a broad distribution spanning North America, Europe, North Africa, Turkey, Israel, the Caucasus, Russia, Central Asia, China, Korea, and Japan. The species is part of a large genus of active hunting spiders that do not build webs to capture prey.
Haplodrassus stuxbergi
Haplodrassus stuxbergi is a ground spider in the family Gnaphosidae, described by L. Koch in 1879. The species has a transcontinental distribution spanning northern Eurasia and North America. Like other members of its genus, it is a ground-dwelling hunter. Published ecological and behavioral details remain limited.
Harmandiola
Harmandiola is a genus of gall midges (family Cecidomyiidae) comprising 14 described species distributed across the Holarctic region. These small flies are notable for inducing galls on woody host plants, specifically species of poplar (Populus), chestnut (Castanea), and hickory (Carya). The genus was established by Skuhravá in 1997. Species-level taxonomy has been revised multiple times, with several species transferred from related genera.
Harpalobrachys leiroides
Harpalobrachys leiroides is a ground beetle species and the sole member of its genus. It is classified within the subfamily Harpalinae, tribe Harpalini. The species has a Holarctic distribution spanning northern Eurasia and North America. It was first described by Motschulsky in 1844.
Harpalus fuscipalpis
Harpalus fuscipalpis is a species of ground beetle in the subfamily Harpalinae, described by Sturm in 1818. It belongs to the genus Harpalus, one of the largest genera of ground beetles. The species has a Holarctic distribution, with records from Alaska, Armenia, Austria, and Azerbaijan. As a member of the Carabidae family, it is likely a predatory beetle, though specific ecological details remain poorly documented.
Hartigiini
Hartigiini is a tribe of stem sawflies in the family Cephidae. Members are characterized by their elongated, cylindrical bodies and reduced wing venation relative to other sawflies. The tribe contains several genera distributed primarily in the Holarctic region. These insects are associated with woody plants, where larvae develop internally in stems.
Hedya
Hedya Moths
Hedya is a genus of tortricid moths in the subfamily Olethreutinae. The genus was established by Jacob Hübner in 1825. Species in this genus are found across the Holarctic region, with records from Europe and North America. The genus contains multiple species, though specific species-level information is limited in the provided sources.
Heleodromia
Heleodromia is a genus of small predatory flies in the family Brachystomatidae (subfamily Trichopezinae), with approximately 25 described species distributed across the Holarctic region. The genus was established by Alexander Henry Haliday in 1833 and has been subject to recent taxonomic revision in the Nearctic region. Species are characterized by distinctive male terminalia used for species identification.