Holarctic
Guides
Phylloneta impressa
Forest Cobweb Weaver
Phylloneta impressa is a small comb-footed spider (Theridiidae) with a Holarctic distribution. Males measure 2.5–5.5 mm and females 3.5–5.5 mm. The species constructs tangle webs beneath retreats on vegetation and has been documented in agricultural settings including rape fields. It is closely related to and frequently confused with Phylloneta sisyphia.
Phyllotreta zimmermanni
Zimmerman's flea beetle
Phyllotreta zimmermanni, commonly known as Zimmerman's flea beetle, is a species of flea beetle in the family Chrysomelidae. It has a holarctic distribution and is present in North America, where it is considered invasive. The species belongs to a genus known for including significant agricultural pests that damage cruciferous crops.
Phymatocerini
Phymatocerini is a small tribe of sawflies within the family Tenthredinidae, comprising approximately 7 genera and 11 described species. Members of this tribe are part of the suborder Symphyta, characterized by a broad connection between the thorax and abdomen rather than the constricted waist seen in most other Hymenoptera. The tribe is taxonomically compact and represents a distinct lineage within the common sawflies.
Physatocheila
Physatocheila is a genus of lace bugs in the family Tingidae, established by Fieber in 1844. The genus comprises at least 50 described species distributed across the Holarctic region, with documented occurrences in Europe (Denmark, Norway, Sweden), North America (United States), and Asia (China, Russian Far East). Species have been described from diverse geographic regions including Sichuan and Yunnan provinces in China, and the southern Primorskiy Territory in the Russian Far East.
Phytomyptera
Phytomyptera is a genus of tachinid flies (Diptera: Tachinidae) in the tribe Graphogastrini, comprising approximately 60 described species distributed across the Holarctic region. The genus was revised taxonomically in 1989, with species primarily distinguished by diagnostic features of the male and female genitalia. European species are particularly well-documented, with 12 species currently recognized from this region.
Piezura
Piezura is a small genus of small flies in the family Fanniidae, distinguished from other fanniid genera by its plumose arista. The genus contains five described species with distribution primarily in the Holarctic region. Two species, P. pardalina and P. graminicola, occur in Europe. Recent taxonomic revision has clarified species concepts, redescribed all species, and provided illustrated genitalia and identification keys for both sexes.
Pionini
Pionini is a tribe of ichneumonid wasps within the subfamily Pioninae. These parasitoid wasps are characterized by distinctive morphological features including elongated bodies and specialized ovipositor structures. The tribe comprises multiple genera of moderate to large-sized wasps. They are primarily known from the Northern Hemisphere with limited published biological data.
Pipizinae
Pitheads & Kin
Pipizinae is a subfamily of hoverflies (Syrphidae) containing approximately 70 species across eight extant genera. Formerly classified as a tribe within Eristalinae, molecular phylogenetic studies published in 2015 reinstated it as a distinct subfamily, sister to Syrphinae. Members are small to medium-sized flies, predominantly black in coloration with some species displaying orange abdominal markings. The subfamily is notable for its specialized larval predation on aphids, particularly wax-secreting species.
Pirata
pirate wolf spiders
Pirata is a genus of wolf spiders (family Lycosidae) commonly known as pirate wolf spiders. These spiders are characterized by their association with moist habitats and distinctive eye arrangement typical of lycosids. The genus was established by Sundevall in 1833 and contains multiple species distributed across North America and Eurasia. Pirata species are active hunters that do not build permanent webs for prey capture.
Pirata piraticus
Pirate Otter Spider
Pirata piraticus is a wolf spider in the family Lycosidae with a Holarctic distribution spanning North America, Europe, and Asia. Unlike the wandering hunting strategy typical of many wolf spiders, this species constructs small sheet webs with retreat tubes in moist Sphagnum moss habitats. It exhibits complex life history variation with two reproductive cohorts: early-emerging individuals mature and reproduce in the same year, while late-emerging individuals overwinter and reproduce the following spring.
Plagodis
Plagodis is a genus of geometrid moths established by Jacob Hübner in 1825. The genus includes approximately 30 described species distributed across the Holarctic region, with notable diversity in both Europe and North America. Several species are recognized for their distinctive wing patterns and resting postures. The genus name derives from Greek, referring to the oblique or slanted wing posture characteristic of many species at rest.
Planolinellus
Planolinellus is a genus of scarab beetles in the family Scarabaeidae, subfamily Aphodiinae. The genus was established by Dellacasa & Dellacasa in 2005. It belongs to the tribe Aphodiini and is part of the diverse group of dung beetles and related taxa within the scarab family. Species in this genus are small to medium-sized beetles associated with decomposing organic matter.
Planolinellus vittatus
Planolinellus vittatus is a species of dung beetle in the family Scarabaeidae, subfamily Aphodiinae. Originally described as Aphodius vittatus by Thomas Say in 1825, it was later transferred to the genus Planolinellus. The species has a broad distribution spanning the Holarctic region, with records from North America, Europe, and Asia.
Planolinoides borealis
Mouse Dung Beetle
Planolinoides borealis, commonly known as the Mouse Dung Beetle, is a small scarab beetle in the subfamily Aphodiinae. The species has a broad Holarctic distribution, occurring across northern North America and Eurasia. It is associated with rodent burrows and nests, where it feeds on dung and organic matter. The species was first described by Gyllenhal in 1827.
Plateumarini
Plateumarini is a tribe of leaf beetles within the subfamily Donaciinae, established by Böving in 1922. Members of this tribe are aquatic or semi-aquatic beetles associated with freshwater habitats. The tribe is distinguished from the related tribe Donaciini by morphological features of the larval stage, particularly in the structure of the respiratory siphon. Plateumarini contains the genus Plateumaris, which is the primary genus in this group.
Plateumaris
spade reed beetles
Plateumaris is a genus of aquatic leaf beetles in the family Chrysomelidae, subfamily Donaciinae, distributed across the Holarctic region. The genus comprises approximately 27 species globally, with 17 described in North America and 10 in the Palaearctic. Adults are found along margins of water bodies on emergent aquatic plants, while larvae develop submerged on plant roots. Species are recognized by diagnostic morphological features including the lack of pubescence above the procoxa and rounded, declivous elytral apices with a sinuate sutural area. Females possess a strongly sclerotized, shovel-like ovipositor that often protrudes from the abdomen, giving rise to the common name "spade reed beetles".
Platnickina tincta
False Pirate Spider
Platnickina tincta is a small tangle web spider (family Theridiidae) with a Holarctic distribution, native to Europe and northern Asia and introduced to North America. It is the type species of the genus Platnickina, originally described from Paris, France. The species is commonly known as the False Pirate Spider.
Platycheirus
Sedgesitters
Platycheirus is a large genus of hoverflies (family Syrphidae) commonly known as sedgesitters. The genus was established in 1828 and is primarily Holarctic in distribution, with approximately 110 species in the Palearctic and 70 in the Nearctic region. Species are slender, small to medium-sized flies, often with distinctive leg modifications in males used for species identification.
Platycheirus scutatus
hoverfly
Platycheirus scutatus is a very common Holarctic hoverfly with a wide distribution across the Northern Hemisphere. Adults are notable pollinators that feed on diverse flowers, while larvae are aphid predators. The species has an exceptionally long flight period and may remain active during cold weather. Multiple broods occur throughout warmer months.
Platymya
Platymya is a genus of tachinid flies (family Tachinidae) established by Robineau-Desvoidy in 1830. The genus contains four recognized species distributed in the Holarctic region. As members of the tribe Goniini, these flies are parasitoids, though specific host associations for most species remain poorly documented.
Platypeza
flat-footed flies
Platypeza is a genus of flat-footed flies in the family Platypezidae, established by Meigen in 1803. The genus contains at least 30 described species. Members are small to medium-sized flies characterized by their distinctive flattened hind tarsi, a trait that gives the family its common name. These flies are part of the diverse Diptera fauna found primarily in forested environments of the Northern Hemisphere.
Platypezidae
Flat-footed Flies
Platypezidae is a family of small true flies (Diptera) comprising over 250 species worldwide. Adults are commonly known as flat-footed flies due to their characteristically modified tarsal segments, particularly in males. The family is primarily associated with woodland habitats where larvae develop as fungivores. Adults exhibit distinctive swarming behavior for mating and are frequently observed performing rapid, erratic movements on vegetation. The family was formerly broader in circumscription, with Opetiidae and some genera now placed in Atelestidae removed based on phylogenetic evidence.
Platypsyllinae
mammal-nest beetles
Platypsyllinae is a subfamily of small beetles within Leiodidae, commonly known as mammal-nest beetles. The group was formerly recognized as the family Leptinidae, but was reclassified as a subfamily based on nomenclatural priority. Members of this subfamily are specialized inhabitants of mammal nests and burrows, exhibiting adaptations for this commensal lifestyle. The subfamily includes four genera: Leptinillus, Leptinus, Platypsyllus, and Silphopsyllus.
Plebejus glandon rusticus
Rustic Blue
Plebejus glandon rusticus is a subspecies of Arctic Blue butterfly in the family Lycaenidae. It belongs to a genus of small, often iridescent blue butterflies commonly known as "blues." The species Plebejus glandon has a Holarctic distribution with multiple described subspecies showing regional variation. Subspecific status indicates geographic differentiation in morphology or ecology from the nominate form.
Plectrura
Plectrura is a genus of longhorn beetles in the subfamily Lamiinae, tribe Parmenini. The genus was established by Mannerheim in 1852 and contains at least two species: Plectrura spinicauda and Plectrura metallica. Members of this genus are classified within the diverse cerambycid fauna of the Holarctic region.
Plusia putnami
Putnam's Looper Moth, Lempke's Gold Spot
Plusia putnami is a noctuid moth with a trans-Holarctic distribution, occurring across northern Eurasia from Japan to western Europe and throughout much of North America. Adults are active from July to August in western Europe and May to October in northern North America. The species is notable for requiring genitalic dissection to reliably distinguish it from the similar Plusia festucae, as wing pattern differences between the two are not constant. The wingspan ranges from 32–42 mm.
Podura
Podura is a genus of springtails (Collembola) constituting the sole genus of the family Poduridae and superfamily Poduroidea. The genus contains four described species, including the widespread Podura aquatica and two fossil species from Baltic amber. Members are characterized by their stout body form and are among the more morphologically distinct springtail lineages.
Podura aquatica
water springtail
Podura aquatica, commonly known as the water springtail, is one of only four described species in the family Poduridae. It is exclusively aquatic, living its entire life on the surface of still water bodies where it scavenges. The species exhibits specialized sensory adaptations for locating water surfaces through polarized light detection. Adults possess a large, flattened furcula that enables jumping without breaking water surface tension. The species has a Holarctic distribution and is considered abundant across its range.
Poecilochirus
Carrion Beetle Mites
Poecilochirus is a Holarctic genus of relatively large mites (0.5–1 mm) in the family Parasitidae. They are phoretic symbionts of burying beetles (Silphidae: Nicrophorus), using beetles for transport to vertebrate carcasses where they feed and reproduce. The genus exhibits extensive cryptic diversity, with molecular studies identifying 24 genetic clusters potentially representing distinct species. Their interaction with beetle hosts is context-dependent, ranging from antagonistic (egg predation, competition) to potentially mutualistic (preying on fly eggs and nematodes).
Poeciloneta
Poeciloneta is a genus of sheet web spiders (family Linyphiidae) established by Kulczyński in 1894, with Neriene variegata as the type species. The genus contains approximately 15 species distributed across the Holarctic region, including North America, Europe, Russia, and China. Most species are small-bodied spiders that construct flat sheet webs. The genus has not undergone modern taxonomic revision.
Pollenia rudis
common cluster fly, attic fly, loft fly, buckwheat fly
Pollenia rudis, the common cluster fly, is a medium-sized blow fly in the family Polleniidae. Adults are notable nuisance pests of buildings, overwintering in attics and wall voids in large aggregations during cold months. The species is an obligate parasite of earthworms in its larval stages, with well-documented host specificity to certain lumbricid species. Native to Europe, it has been introduced to North America and New Zealand, where it occurs wherever its earthworm hosts are present.
Polychrysia esmeralda
delphinium leaftier
Polychrysia esmeralda, commonly known as the delphinium leaftier, is a noctuid moth described by Charles Oberthür in 1880. The species name derives from Greek roots meaning "many" and "gold," referring to the adult's shining golden wing coloration. It occurs across northern North America and eastern Siberia, with larvae specializing on toxic Ranunculaceae host plants including monkshood and delphinium. The species is notable for its distinctive larval behavior of tying leaves together with silk and spinning a gold-colored cocoon within.
Polydesmidae
flat-backed millipedes, tractor millipedes
Polydesmidae is a family of millipedes in the order Polydesmida comprising over 240 species across more than 30 genera. These millipedes are characterized by their flattened, plate-like dorsal exoskeletons that give them the common name "flat-backed millipedes." They range from 4 mm to 30 mm in length and display coloration from black through brownish to pallid, rarely vivid. The family has a predominantly Holarctic distribution extending to Mexico, North Africa, and Java, with highest diversity in the Mediterranean region. Several species exhibit notable biological traits, including sexual dimorphism in segment number and chemical defense secretions.
Polymerus
Polymerus is a genus of plant bugs in the family Miridae, containing at least 100 described species. The genus was established by Hahn in 1831 and has been subject to extensive taxonomic revision, particularly for Eastern Hemisphere species. Species occur across the Holarctic region, with records from Europe, North America, Africa, India, Australia, and Madagascar. The genus includes subgenera Polymerus and Pachycentrum, with some species previously assigned to Polymerus now transferred to other genera such as Dichelocentrum and Charagochilus.
Polyporivora
flat-footed flies
Polyporivora is a genus of flat-footed flies (Platypezidae) comprising approximately eight described species. The genus is distinguished by its obligate association with polypore fungi, where larvae develop within host fruiting bodies. Species occur primarily in the Holarctic region, with documented records from Europe, including recent rediscoveries in Central and Southern Europe. The genus was established by Kessel & Maggioncalda in 1968.
Polyxenus lagurus
Bristly Millipede
Polyxenus lagurus, commonly known as the bristly millipede, is a small millipede species distinguished by its detachable defensive bristles that entangle attacking ants and spiders. It exhibits a unique reproductive polymorphism, with some populations reproducing sexually and others parthenogenetically. This species undergoes hemianamorphosis, adding segments and legs through juvenile molts until reaching a fixed adult complement of 13 leg pairs and 10 tergites, after which molting continues without further segment addition. It is the most common polyxenid in Europe and the only representative of order Polyxenida in the British Isles.
Pontia
whites
Pontia is a genus of pierid butterflies in the family Pieridae, commonly referred to as the "whites." These butterflies are distributed across the Holarctic region, with species found in North America, Europe, and Asia, though they are relatively rare in central and eastern North America and Europe. Several species formerly classified in Pontia have been reassigned to the genus Sinopieris. The genus includes well-known species such as the Checkered White (Pontia protodice) and the Spring White (Pontia sisymbrii).
Porrhomma convexum
Porrhomma convexum is a species of sheetweb spider in the family Linyphiidae, characterized by its small size and association with cave and subterranean habitats. The species was described by Westring in 1851 and has a broad Holarctic distribution spanning North America, Europe, and Asia. Like other members of its genus, it exhibits adaptations to dark environments including reduced pigmentation and eye size. The species constructs sheet webs typical of its family.
Praon
Praon is a genus of braconid wasps in the subfamily Aphidiinae containing at least 70 described species. Species are solitary parasitoids of aphids, with females laying eggs inside living hosts. Several species are important biological control agents in agricultural systems. Notable species include P. pequodorum, a native North American parasitoid that outcompeted introduced Aphidius ervi on bacterially-defended pea aphids, and P. volucre, a commercially produced biocontrol agent that exhibits facultative pupal diapause.
Prionini
Prionini is a tribe of large, robust longhorn beetles (Cerambycidae: Prioninae) characterized by their substantial body size, strong mandibles, and often somber coloration. Members of this tribe are distinguished from other Prioninae by their relatively small compound eyes, an adaptation associated with diurnal activity patterns. The tribe includes several genera distributed across the Holarctic and Oriental regions, with taxonomic revisions ongoing due to the group's morphological diversity and historical classification challenges.
Prionocera
Prionocera is a genus of crane flies (family Tipulidae) established by Loew in 1844. The genus contains approximately 22 described species distributed primarily across the Holarctic region. Species have been described from North America, Europe, and East Asia. The genus is characterized by features of the male genitalia, particularly the structure of the ninth tergite and gonostyli.
Pristiphora erichsonii
Larch Sawfly
Pristiphora erichsonii, commonly known as the larch sawfly, is a species of sawfly native to Europe that was introduced to North America in the mid-to-late 19th century. It is a significant defoliator of larch trees (Larix spp.), particularly tamarack (Larix laricina) in North America. The species undergoes population outbreaks that can cause severe defoliation, though trees typically recover from single-year damage. Severe defoliation over multiple years can weaken trees and reduce winter survival. The species has been the subject of extensive ecological and population dynamics research due to its economic importance in forestry.
Pristiphora mollis
Gentle Bilberry Sawyer
Pristiphora mollis is a Holarctic sawfly species in the family Tenthredinidae, commonly known as the Gentle Bilberry Sawyer. The species occurs across northern regions of both North America and Eurasia, with documented records in Canada and the United Kingdom. Like other members of the genus Pristiphora, it is associated with woody plants, though specific host relationships require further documentation.
Procas
Procas is a Holarctic genus of weevils (Coleoptera: Erirhinidae) established by Stephens in 1831. The genus comprises six recognized species distributed across the western Palaearctic (four species), eastern Palaearctic (one species), and Nearctic (one species). Species-level identification relies partly on male sternite 8 characters, a technique first applied to this genus in a 2004 revision. Recent taxonomic work has clarified synonymies and restored related genera Notodermus and Apachiscelus from synonymy with Procas.
Prodiamesinae
Prodiamesinae is a subfamily of non-biting midges in the family Chironomidae. The subfamily contains at least four extant genera: Compteromesa, Monodiamesa, Odontomesa, and Prodiamesa, with additional fossil genera known from Cretaceous amber deposits. Species have been documented across the Holarctic region, including the Russian Far East, Tibetan Plateau, and North America. The subfamily has been subject to both morphological and molecular taxonomic studies, particularly for species discrimination using DNA barcoding.
Profenusa
oak mining sawflies, birch leafmining sawflies
Profenusa is a genus of leaf-mining sawflies in the family Tenthredinidae. Species in this genus are primarily associated with trees in the genera Quercus (oaks) and Betula (birches), though at least one species, P. japonica, has been documented on Rosa multiflora. Larvae are internal leaf miners that feed on mesophyll tissue, creating blotch mines. Several species are economically significant as forest and urban pests, including the invasive P. pygmaea in Kazakhstan and P. thomsoni in North America.
Protapanteles
Protapanteles is a genus of braconid wasps in the subfamily Microgastrinae, containing more than 20 described species distributed mainly in the Holarctic region. Species are koinobiont endoparasitoids of lepidopteran larvae, with documented hosts including geometrid moths and nymphalid butterflies. Some species, particularly P. immunis, have been investigated for biological control of agricultural pests. The genus has been subject to taxonomic revision, with phylogenetic studies indicating paraphyly and close relationships with Cotesia.
Proteinus brachypterus
Proteinus brachypterus is a small rove beetle (Staphylinidae) characterized by reduced hind wings (brachyptery), a trait reflected in its species name. It is widely distributed across the Holarctic region, with confirmed records from Europe, North Africa, the Middle East, Russia, and western North America. The species inhabits various decaying organic substrates and is associated with forest floor and riparian environments. Like other members of Proteininae, it is presumed to be a predator or scavenger in microarthropod communities, though specific ecological studies are limited.
Protocalliphora
bird blowflies, bird blow flies
Protocalliphora is a genus of blow flies (Calliphoridae) comprising obligate hematophagous parasites of birds. Larvae develop in bird nests and feed on the blood of nestlings, with more than 140 bird species recorded as hosts. The genus is distributed across the Holarctic region (Nearctic and Palaearctic). Adults overwinter and exhibit complex interactions with Wolbachia endosymbionts that complicate species identification through DNA barcoding.
Protocalliphora bennetti
Protocalliphora bennetti is a species of blow fly in the family Calliphoridae, described by Whitworth in 2002. The genus Protocalliphora comprises nest parasites of birds, with larvae developing in the blood of nestling birds. This species is one of approximately 20 recognized species in the genus, which are distributed primarily in the Holarctic region. Like congeners, P. bennetti likely exhibits the characteristic life history of bird nest parasitism that defines the genus.