Western-north-america
Guides
Omus submetallicus
Lustrous Night-stalking Tiger Beetle, Smith's Brome
Omus submetallicus is a nocturnal tiger beetle species in the family Cicindelidae, found in western North America. Adults are active at night and have been observed hunting in intertidal zones, capturing amphipods at low tide. The species has historically been confused with Omus californicus lecontei, leading to taxonomic uncertainty and unclear conservation status. Two subspecies are recognized: O. submetallicus submetallicus and O. submetallicus niger.
Oncopsis californica
Oncopsis californica is a species of leafhopper in the family Cicadellidae, described by Van Duzee in 1917. The species is known from limited collection records in western North America, specifically California and British Columbia. As a member of the genus Oncopsis, it belongs to a group of leafhoppers typically associated with woody host plants, though specific biological details for this species remain poorly documented.
Oneida luniferella
Oneida luniferella is a species of snout moth in the family Pyralidae, described by George Duryea Hulst in 1895. The species occurs in western North America, including the western United States and Mexico. Two subspecies are recognized: the nominate O. l. luniferella and O. l. pallidalis described by Barnes & Benjamin in 1924.
Onocosmoecus
Onocosmoecus is a genus of caddisflies in the family Limnephilidae, established by Banks in 1943. The genus contains three described species: O. occidentalis, O. sequoiae, and O. unicolor. These are northern caddisflies distributed in western North America, with larvae that construct portable cases. The genus is classified within the subfamily Dicosmoecinae, a group of case-making caddisflies often associated with cool, running waters.
Opeia
obscure grasshopper
Opeia is a genus of slant-faced grasshoppers in the family Acrididae, subfamily Gomphocerinae, tribe Eritettigini. It was described by McNeill in 1897. The genus contains at least two described species: Opeia atascosa (atascosa grasshopper) and Opeia obscura (obscure grasshopper). Opeia obscura is the more widely documented species and has been recorded in grasshopper surveys across western North America.
Operophtera occidentalis
Western Bruce Spanworm
Operophtera occidentalis, commonly known as the Western Bruce Spanworm, is a moth species in the family Geometridae. It is native to western North America. The species is closely related to the Bruce spanworm (Operophtera bruceata), with which it shares similar ecological traits and appearance. Adults are active in late autumn, with males possessing fully developed wings while females are wingless.
Ophryastes argentatus
silver broad-nosed weevil
Ophryastes argentatus is a species of broad-nosed weevil in the beetle family Curculionidae, first described by LeConte in 1853. The species is found in western North America, with records from California, Arizona, Nevada, Utah, and Baja California. The specific epithet 'argentatus' refers to the silvery appearance of the beetle. It belongs to the subfamily Entiminae, a group of weevils commonly known as broad-nosed weevils due to their relatively short, broad rostrums compared to other weevil groups.
Ophryastes geminatus
broad-nosed weevil
Ophryastes geminatus is a species of broad-nosed weevil in the family Curculionidae. It belongs to the subfamily Entiminae, a group characterized by their broad, short rostrums. The species was described by Horn in 1876 and is known from western North America.
Ophryastes varius
broad-nosed weevil
Ophryastes varius is a species of broad-nosed weevil in the family Curculionidae, first described by John Lawrence LeConte in 1853. It belongs to the tribe Ophryastini within the subfamily Entiminae. The species has been recorded from western North America, with distribution records from Arizona, California, Idaho, Nevada, and Baja California.
Orchestomerus eisemani
Orchestomerus eisemani is a species of weevil described in 2015 from the western United States. The species belongs to the genus Orchestomerus, a group of small weevils within the family Curculionidae. It has been documented in California and Oregon, primarily in association with coniferous forest habitats. The species was named in honor of entomologist Robert Eiseman.
Oreodytes snoqualmie
Oreodytes snoqualmie is a species of predaceous diving beetle in the family Dytiscidae. It was described by Hatch in 1933 and was originally placed in the genus Hydroporus. The species is known from western North America, with records from Alberta and British Columbia in Canada. As a member of the genus Oreodytes, it belongs to a group of small diving beetles typically associated with lotic (flowing water) habitats.
Oreopasites
Oreopasites is a genus of cuckoo bees in the family Apidae, first described by Cockerell in 1906. The genus comprises approximately 11 described species, all of which are kleptoparasitic bees that lay their eggs in the nests of host bees. Species in this genus are found in western North America, particularly in arid and semi-arid regions. The genus is classified within the tribe Ammobatini of the subfamily Nomadinae.
Orgerius concordus
Orgerius concordus is a species of planthopper in the family Dictyopharidae, described by Ball & Hartzell in 1922. The species belongs to the subfamily Orgeriinae, a group of planthoppers often associated with arid and semi-arid environments. It is known from a limited number of records in California and Baja California. The genus Orgerius contains relatively few described species, and O. concordus remains poorly studied with minimal published biological information.
Orgerius pajaronius
Orgerius pajaronius is a species of planthopper in the family Dictyopharidae, described by Ball & Hartzell in 1922. It belongs to the tribe Orgeriini, a group characterized by elongated bodies and often associated with grassland habitats. The species is known from the western United States, with records from California and Oregon. Like other dictyopharids, it is presumed to feed on plant sap using piercing-sucking mouthparts.
Orgerius rhyparus
Orgerius rhyparus is a planthopper species in the family Dictyopharidae, described by Carl Stål in 1859. It belongs to the subfamily Orgeriinae, a group of dictyopharid planthoppers often associated with arid and semi-arid environments. The species has been recorded from western North America, including the southwestern United States and northwestern Mexico. Like other members of its family, it possesses an enlarged, often elaborately modified head structure.
Orgyia pseudotsugata
Douglas-fir tussock moth
A western North American tussock moth known for periodic population outbreaks that cause significant defoliation of conifer forests. Males are winged and grayish-brown with feathery antennae, while females are flightless with rudimentary wings. Caterpillars are distinctive with red spots, white spines, and prominent red-tipped white tussocks. The species undergoes cyclical outbreaks every 8-12 years that can persist for up to four years.
Orgyia vetusta
Western Tussock Moth
Orgyia vetusta, the Western Tussock Moth, is a species of tussock moth in the family Erebidae. It is native to western North America, ranging from British Columbia through the Pacific States to New Mexico, with an isolated population in Idaho. The species is known to undergo periodic outbreaks, and females are wingless while males possess functional wings. Larvae are notable for their distinctive hair tufts and tussocks.
Orohermes crepusculus
Orohermes crepusculus is a species of fishfly in the family Corydalidae, originally described as Dysmicohermes crepusculus by Chandler in 1954. It is one of several species in the genus Orohermes, which comprises small to medium-sized megalopterans found in western North America. The species epithet "crepusculus" refers to twilight, possibly alluding to crepuscular activity patterns. Adults are weak fliers and are often attracted to lights.
Oroperla
Oroperla is a genus of stoneflies in the family Perlodidae, established by Needham in 1933. Members of this genus are classified within the tribe Arcynopterygini and are part of the diverse Systellognatha infraorder. The genus is documented from western North America, specifically California and Nevada. As a perlodid stonefly, it likely inhabits cool, flowing freshwater systems typical of the family.
Oroperla barbara
Gilltail Springfly
Oroperla barbara is a stonefly species in the family Perlodidae, first described by Needham in 1933. It is commonly known as the Gilltail Springfly. The species is recorded from California and Nevada in western North America. As a member of the order Plecoptera, it belongs to an ancient group of aquatic insects with gilled immature stages and terrestrial adults.
Oropodes
Oropodes is a genus of minute rove beetles in the subfamily Pselaphinae, characterized by reduced elytra and compact body form typical of the tribe Trichonychini. Members are among the smallest staphylinid beetles, with most species measuring under 2 mm. The genus was established by Casey in 1893 and is currently placed within the subtribe Trichonychina. These beetles inhabit forest litter and soil microhabitats where they function as microbivores or predators on small arthropods.
Oropus cavicauda
ant-loving beetle
Oropus cavicauda is a species of ant-loving beetle in the family Staphylinidae, first described by Casey in 1893. It belongs to the subfamily Pselaphinae, a diverse group of small rove beetles frequently associated with ant colonies. The species has been documented in the western United States, specifically California and Oregon. Available information on this species remains limited.
Oropus striatus
ant-loving beetle
Oropus striatus is a small rove beetle in the family Staphylidae, subfamily Pselaphinae. The species was described by John Lawrence LeConte in 1874. It is known from western North America, with records from British Columbia, California, Oregon, and Washington. Like other members of the Pselaphinae, it is associated with ant colonies.
Orothrips
Orothrips is a genus of predatory thrips in the family Aeolothripidae, established by Moulton in 1907. Members of this genus are small, slender insects with fringed wings characteristic of the order Thysanoptera. As aeolothripids, they are presumed to be predatory, though species-specific biology remains poorly documented. The genus is part of a family known for biological control potential against pest mites and small insects.
Orthosia pacifica
Pacific Quaker
Orthosia pacifica, commonly known as the Pacific Quaker, is a species of cutworm or dart moth in the family Noctuidae. It is found in western North America. The species was first described by Harvey in 1874 under the basionym Taeniocampa pacifica. Adults exhibit characteristic gray-brown coloration with patterned forewings and whitish hindwings. The species is assigned MONA/Hodges number 10494.
Orthotylus coagulatus
Orthotylus coagulatus is a species of plant bug in the family Miridae. It belongs to a large genus of mirid bugs found primarily in the Northern Hemisphere. The species has been documented in the western United States, with records from Colorado and Nevada. Like other members of its genus, it is likely associated with vegetation and may be attracted to lights at night.
Oskoron spinosus
Oskoron spinosus is a harvestman (order Opiliones) and the type species of the genus Oskoron, established to accommodate this species and two close relatives distinct from the genus Taracus. Originally described as Taracus spinosus by Banks in 1894, it was later treated as Taracus malkini before being synonymized and transferred to the new genus Oskoron. It belongs to the family Taracidae within the superfamily Ischyropsalidoidea.
Osmia coloradensis
Colorado Mason, Colorado osmia
Osmia coloradensis is a solitary mason bee in the family Megachilidae, native to western North America. Like other Osmia species, it nests in pre-existing cavities such as hollow plant stems or holes in wood, sealing nest chambers with mud. The species is recognized as a native pollinator with documented observations across multiple western U.S. states and parts of Central America. It belongs to a genus of bees increasingly valued for orchard pollination services, though specific management practices for this species are less developed than for commercially used relatives.
Osmia lignaria propinqua
Western Blue Orchard Bee, Blue Orchard Bee, BOB
Osmia lignaria propinqua is a solitary, cavity-nesting mason bee native to western North America, commonly known as the Western Blue Orchard Bee or BOB. It is a subspecies of the blue orchard bee and is valued as a highly efficient pollinator of early-blooming fruit trees including almonds, cherries, apples, and plums. Females carry dry pollen on the scopa (hairs) beneath the abdomen rather than on leg baskets, and they forage at lower temperatures and for more hours than honey bees. The species is managed commercially in orchards, where it is often deployed alongside honey bees to improve cross-pollination through its tendency to move between trees rather than forage systematically on single plants.
Osmia ribifloris ribifloris
blueberry mason bee
Osmia ribifloris ribifloris is a subspecies of mason bee native to western North America, endemic to regions west of the Mississippi River including Texas, California, and Oregon. It has been developed as a commercially managed pollinator for blueberry crops, particularly rabbiteye and southern highbush blueberries, with 14 years of rearing data documented from the Deep South. The subspecies produces cocoons that can be stored and released for field-scale pollination services.
Osobenus
Osobenus is a genus of stoneflies in the family Perlodidae, first described by Ricker in 1952. The genus belongs to the tribe Diploperlini within the subfamily Perlodinae. Species in this genus are found in western North America, with records from British Columbia, Washington, Oregon, and California.
Ospriocerus brevis
Ospriocerus brevis is a species of robber fly in the family Asilidae, described by Martin in 1968. The species is currently recognized as a synonym of Stenopogon brevis in some taxonomic databases. Robber flies in the genus Ospriocerus are large, predatory flies associated with grassland habitats in western North America.
Ospriocerus longulus
Ospriocerus longulus is a species of robber fly in the family Asilidae. It belongs to the subfamily Dasypogoninae. The species was originally described by Loew in 1866 under the name Stenopogon longulus. Robber flies in this genus are predatory insects that capture other flying insects in flight. The genus Ospriocerus contains species distributed across western North America, with some species representing significant range extensions when found in relictual prairie habitats.
Ospriocerus minos
Ospriocerus minos is a species of robber fly in the family Asilidae, originally described by Osten Sacken in 1877. The species has been treated as a synonym of Stenopogon minos in some taxonomic databases, indicating ongoing taxonomic uncertainty. As a member of the subfamily Stenopogoninae, it belongs to a group of predatory flies characterized by their streamlined bodies and predatory habits. Very few observations of this species have been documented, with only a single iNaturalist record noted.
Ospriocerus tequilae
Ospriocerus tequilae is a species of robber fly in the family Asilidae, described by Martin in 1968. The genus Ospriocerus contains large, wasp-mimicking robber flies found in grassland habitats of western North America. The specific epithet 'tequilae' presumably refers to the type locality in Mexico. The species is currently treated as a synonym of Stenopogon tequilae in some taxonomic databases, reflecting ongoing taxonomic uncertainty in the classification of this group.
Ossiannilssonola flavomarginata
A small leafhopper in the family Cicadellidae, originally described from the western United States. The species epithet "flavomarginata" (yellow-margined) suggests distinctive coloration. Records indicate occurrence in arid and semi-arid regions of the southwestern U.S. including Arizona, Colorado, New Mexico, and Utah. As a member of subfamily Typhlocybinae, it likely feeds on plant vascular tissue.
Ozodiceromyia livdahli
Ozodiceromyia livdahli is a species of stiletto fly in the family Therevidae, described by Gaimari and Irwin in 2000. The genus Ozodiceromyia belongs to the mexicana-group, a distinctive clade of cycloteline Therevidae characterized by specialized morphological features. Species in this genus are poorly known biologically, with most information derived from taxonomic revisions rather than ecological studies.
Ozophora occidentalis
Ozophora occidentalis is a species of seed bug in the family Rhyparochromidae, described by Slater in 1988. It is distributed in western North America, with records from Canada and the United States. As a member of the genus Ozophora, it belongs to a group of true bugs primarily associated with seed feeding. The species is part of the tribe Ozophorini within the subfamily Rhyparochrominae.
Ozyptila pacifica
A small crab spider in the family Thomisidae, first described by Nathan Banks in 1895. The species occurs in western North America from Canada through the United States. Like other members of its genus, it exhibits the characteristic crab-like posture and ambush predation strategy typical of thomisid spiders.
Pachodynerus pulverulentus
Keyhole wasp
Pachodynerus pulverulentus is a solitary mason wasp in the subfamily Eumeninae, commonly known as a keyhole wasp. It belongs to a genus of wasps that utilize pre-existing cavities in wood—such as abandoned beetle galleries, old nail holes, or hollow twigs—as nesting sites. Like other Pachodynerus species, females provision these cavities with paralyzed caterpillars as food for their developing larvae. The species was described by Viereck in 1908 and is part of a group of wasps known for their opportunistic nesting behavior and importance as biological control agents of caterpillar pests.
Pacifastacus
Pacific Crayfish
Pacifastacus is a genus of freshwater crayfish endemic to western North America, comprising six species including the widespread signal crayfish (P. leniusculus) and two extinct species. The genus has gained significant conservation attention due to the invasive spread of P. leniusculus in Europe and Japan, where it transmits crayfish plague and displaces native species. Within its native range, several Pacifastacus species face population declines from habitat degradation and competition from invasive crayfishes.
Pacifastacus gambelli
Pacifastacus gambelli is a species of crayfish in the family Astacidae. The genus Pacifastacus is native to western North America, with species distributed across freshwater habitats in the Pacific Northwest and Rocky Mountain regions. P. gambelli is closely related to other Pacifastacus species including the widely studied signal crayfish (P. leniusculus), which has become a notorious invasive species in Europe. The species epithet 'gambelli' honors William Gambel, an American naturalist and explorer of the western United States in the 19th century.
Pacificanthia consors (LeConte, 1851)
brown leatherwing beetle
Pacificanthia consors, commonly known as the brown leatherwing beetle, is a soldier beetle (family Cantharidae) native to western North America. Adults are active in spring, particularly April and May, and are associated with plant litter habitats. The species exhibits predatory habits in both adult and larval stages.
Pagaronia confusa
Pagaronia confusa is a leafhopper species in the family Cicadellidae, first described by Oman in 1938. It belongs to the subfamily Evacanthinae and is one of several species within the genus Pagaronia, which is characterized by distinctive morphological features typical of this leafhopper group. The species has been documented in western North America.
Palonica pyramidata portola
Palonica pyramidata portola is a subspecies of treehopper in the family Membracidae, subfamily Smiliinae. It was described by Ball in 1931. The species Palonica pyramidata belongs to the tribe Telamonini, a group of treehoppers known for their often elaborate pronotal modifications. The subspecies epithet "portola" suggests a type locality or association, though specific details are not documented in available sources. Records indicate occurrence in Colorado, USA.
Paltothemis
Rock Skimmers
Paltothemis is a genus of skimmer dragonflies in the family Libellulidae, established by Karsch in 1890. The genus contains at least three described species, commonly known as Rock Skimmers. The best-known species, Paltothemis lineatipes (Red Rock Skimmer), has been studied for its variable mating system, which shifts between territorial defense and alternative strategies depending on male population density. Members of this genus are associated with rocky stream habitats in western North America.
Pandemis pyrusana
apple pandemis, pandemis leafroller moth
Pandemis pyrusana is a tortricid moth native to western North America, commonly known as the apple pandemis or pandemis leafroller moth. It is a significant pest of deciduous fruit trees and ornamental plants, with larvae feeding on leaves by rolling and tying them together. The species has one or two generations per year depending on location, with adults active in late spring and again in autumn in coastal California.
Panscopus abruptus
broad-nosed weevil
Panscopus abruptus is a species of broad-nosed weevil in the family Curculionidae, first described by Casey in 1895. It belongs to the genus Panscopus, a group of weevils characterized by their broad, short rostrums. The species has been documented in western North America, with records from California, British Columbia, and several other locations. Very few observations exist in public databases.
Panscopus gemmatus
Panscopus gemmatus is a species of broad-nosed weevil in the family Curculionidae. The species has been documented in western North America, with records from British Columbia, Washington, Oregon, and California. It belongs to the genus Panscopus, a group of weevils characterized by their broad rostrum.
Panscopus ovalis
broad-nosed weevil
Panscopus ovalis is a species of broad-nosed weevil in the beetle family Curculionidae. The species was described by Pierce in 1913 and is currently accepted as valid. It belongs to the subfamily Entiminae, a group of weevils commonly known as broad-nosed weevils due to their relatively short, broad rostrum compared to other weevils. Very little specific biological information has been published for this particular species.