Western-north-america
Guides
Lygus shulli
Lygus shulli is a species of plant bug in the family Miridae, first described by Knight in 1941. It belongs to the economically significant genus Lygus, whose members are major agricultural pests of cotton, strawberries, and other crops. The species occurs in boreal and western regions of North America. Like other Lygus species, it possesses piercing-sucking mouthparts and is associated with herbaceous vegetation.
Lygus striatus
Lygus striatus is a species of plant bug in the family Miridae, first described by Knight in 1917. It belongs to the genus Lygus, which contains several economically significant agricultural pests. The species is distributed across western North America, with records from the western United States and western Canada. Like other members of its genus, it is likely associated with herbaceous vegetation, though specific ecological details remain poorly documented compared to better-studied congeners such as Lygus hesperus and Lygus lineolaris.
Lystridea uhleri
Lystridea uhleri is a species of leafhopper in the family Cicadellidae, subfamily Errhomeninae. Originally described as Bathysmatophorus uhleri by Baker in 1898, it was later transferred to the genus Lystridea. The species is native to western North America and has been recorded from California, Oregon, and Washington. Members of the genus Lystridea are generally associated with coniferous and deciduous forest habitats.
Lytta childi
Lytta childi is a blister beetle in the family Meloidae, classified within the subgenus Poreospasta of the genus Lytta. The species was described by LeConte in 1857 and is known from western North America. Like other Lytta species, it produces cantharidin, a defensive compound toxic to vertebrates. The species is represented in museum collections with 126 specimens at the Entomology Research Museum, indicating it is moderately well-collected but not extensively studied in published literature.
Lytta melaena
Lytta melaena is a species of blister beetle in the family Meloidae, described by LeConte in 1858. It belongs to the subgenus Paralytta within the genus Lytta. The species is known from western North America. Like other members of its genus, it produces cantharidin, a defensive compound that causes blistering upon contact with skin.
Lytta vulnerata
Lytta vulnerata is a blister beetle in the family Meloidae, characterized by bold black and orange aposematic coloration. The species is found in western North America, with subspecies L. v. cooperi occurring in more northerly regions including Idaho. Like other meloids, it produces cantharidin, a defensive compound that causes skin blistering upon contact. Adults have been observed feeding on flowers, particularly rabbitbrush (Chrysothamnus spp.).
Macaria graphidaria
Bold-marked Granite
Macaria graphidaria is a North American moth species in the family Geometridae, described by George D. Hulst in 1887. Adults display distinctive wing patterning with bold, dark markings on a lighter background. The species is associated with coniferous forests and has been documented across western North America. Larval stages feed on conifer foliage.
Macaria occiduaria
The Barred Gray
Macaria occiduaria is a geometrid moth in the tribe Macariini, commonly known as the Barred Gray. The species is characterized by gray forewings with distinct dark transverse lines and a relatively broad wingspan for its genus. It is native to western North America and has been documented in a moderate number of observations. Adults are active during summer months.
Macromya crocata
Macromya crocata is a species of bristle fly in the family Tachinidae. It belongs to the tribe Nemoraeini and was described by Reinhard in 1968. The species is found in North America, where it occurs in forested habitats. Like other tachinid flies, it is a parasitoid, though specific host records for this species remain undocumented. Adults are active during late summer and fall, often observed visiting flowers for nectar.
Macrophya oregona
Macrophya oregona is a sawfly species in the family Tenthredinidae, first described by Cresson in 1880. The species is native to western North America, with records from British Columbia, Canada, and Alaska, United States. As a member of the genus Macrophya, it belongs to a group of sawflies that are typically associated with woody plants. Very little detailed biological information has been published specifically for this species.
Macropsis canadensis
Macropsis canadensis is a species of leafhopper in the family Cicadellidae, first described by Van Duzee in 1890. It belongs to the genus Macropsis, a group of leafhoppers distributed across North America. The species has been recorded from western North American localities including Alberta, British Columbia, California, Colorado, and Idaho. Like other members of its family, it is a phloem-feeding insect that likely inhabits herbaceous vegetation.
Macrosiphoniella ludovicianae
White Sage Aphid
Macrosiphoniella ludovicianae, known as the White Sage Aphid, is a specialist aphid species in the family Aphididae. It is documented from a limited number of observations and appears to be associated with white sage (Salvia apiana) and related Salvia species. The species was described by Oestlund in 1886.
Macrosiphum badium
false Solomon's-seal aphid
Macrosiphum badium, known as the false Solomon's-seal aphid, is a species of aphid described in 2000 by Andrew Jensen. It is endemic to western North America and feeds on west coast species of Maianthemum. The species is characterized by its reddish brown to reddish green coloration and distinctive siphunculi with black tips.
Macrosteles severini
Macrosteles severini is a leafhopper species in the family Cicadellidae, described by Hamilton in 1983. It belongs to a genus known for small, agile insects that feed on plant phloem. The species has been recorded from western North America including Alaska, Arizona, British Columbia, California, Colorado, and Oregon.
Macrosteles vulgaris
Macrosteles vulgaris is a species of leafhopper in the family Cicadellidae, described by Kwon in 2010. The species belongs to the genus Macrosteles, a group of small sap-feeding insects commonly known as leafhoppers. Distribution records indicate occurrence in western North America including British Columbia, California, Idaho, Manitoba, and Montana. As a recently described species, detailed biological information remains limited.
Macrosternodesmidae
Macrosternodesmidae is a family of flat-backed millipedes in the order Polydesmida, primarily distributed in western North America with some European representatives. The family contains approximately 9 genera and 16 described species, though taxonomic status remains disputed—some authorities treat it as a junior synonym of Trichopolydesmidae, while others recognize it as valid with two subfamilies: Macrosternodesminae and Nearctodesminae. Many species are troglobionts restricted to cave systems.
Malacosoma constricta
Pacific tent caterpillar
Malacosoma constricta, the Pacific tent caterpillar, is a moth species endemic to western North America, recorded from California, Oregon, and Washington. The species is specialized on oaks (Quercus spp.) as larval hosts. Two subspecies are recognized in California: M. c. austrinum occurs from Santa Barbara County southward, while M. c. constrictum occurs from Los Angeles County northward. The larvae construct small silken tents for group living and thermoregulation, feeding gregariously on oak foliage.
Mallota sackeni
brown-haltered mimic fly, brown-haltered bee-mimic fly
Mallota sackeni is a species of hover fly (family Syrphidae) native to western North America. The species is known for its bee-mimicry, a common defensive adaptation among syrphid flies. Adults are active pollinators, while larvae develop in aquatic or semi-aquatic environments typical of the tribe Eristalini. The species has been documented from British Columbia to southern California and eastward to Idaho and Utah.
Marchena minuta
Marchena minuta is a small jumping spider and the sole described species in its genus. It is endemic to western North America, where it inhabits the bark of coniferous trees. The species represents the only North American member of the subfamily Heliophaninae. Its distribution is concentrated along the Pacific coast, with records from California, Washington, and Nevada.
Maricopodynerus
Maricopodynerus is a Nearctic genus of potter wasps (family Eumenidae) distributed in western North America. The genus is distinguished by a pronounced morphological feature: the second metasomal segment has a tergum that is substantially larger than its sternum. Species within this genus occur west of the 100° western meridian in the United States and Mexico. The genus was reviewed taxonomically by Bohart in 1989.
Marmara arbutiella
Madrone Skin Miner
Marmara arbutiella is a minute moth in the family Gracillariidae, commonly known as the Madrone Skin Miner. It is characterized by an exceptionally small wingspan of approximately 4 mm. The species is known from western North America, with records from Canada and the United States. Larvae are leaf miners that feed on Arbutus and Arctostaphylos species.
Masarinae
Pollen Wasps
Masarinae, commonly known as pollen wasps, is a subfamily of solitary wasps within Vespidae. Unlike their social and predatory relatives, pollen wasps provision their nests exclusively with pollen and nectar, resembling bees in their foraging behavior. The subfamily is small but globally distributed, with notable diversity in western North America, southern Africa, southern Europe, central Asia, and Australia. In North America, only the genus Pseudomasaris occurs, with 14 species. Many species exhibit strong flower associations, often oligolectic, specializing on particular plant genera such as Penstemon, Phacelia, and Eriodyction.
Matsumurasca elongata
Matsumurasca elongata is a species of leafhopper in the family Cicadellidae, first described by DeLong in 1931. It belongs to the subfamily Typhlocybinae, a group commonly known as typhlocybine leafhoppers. The species has been documented in western North America including British Columbia, Washington, California, and Utah. As a member of the Empoascini tribe, it is related to other economically significant leafhopper genera, though specific information about its biology and ecology remains limited.
Mecaphesa sierrensis
Mecaphesa sierrensis is a species of crab spider in the family Thomisidae, first described by Schick in 1965. The genus Mecaphesa comprises small to medium-sized ambush predators that typically hunt on flowers. As a member of this genus, M. sierrensis likely exhibits the cryptic coloration and sit-and-wait predatory strategy characteristic of flower-dwelling thomisids. The species has been recorded from western North America, including British Columbia, Canada and the United States.
Mectemycor
Mectemycor is a genus of soft-bodied plant beetles comprising three known species, all endemic to California. The genus was established by Majer in 1995 and is currently classified in the family Mauroniscidae, having been historically placed in Melyridae. All three species—M. linearis, M. sericeus, and M. strangulatus—are restricted to western North America.
Megachile fidelis
Faithful Leafcutting Bee, Horn-faced Leafcutter Bee
Megachile fidelis is a solitary leafcutting bee native to western North America. Females construct nests using circular pieces cut from leaves or petals, which they carry back to pre-existing cavities. The species is an important native pollinator frequently observed in gardens and meadows, where it forages on composite flowers. Adults emerge in spring and exhibit a distinctive nesting behavior where offspring remain in brood cells until all intervening cells have been vacated.
Megachile perihirta
Western Leafcutter Bee, Western leafcutting bee
Megachile perihirta, commonly known as the Western Leafcutter Bee, is a solitary bee native to western North America. It is an important pollinator of alfalfa and other crops, recognized by its distinctive leaf-cutting behavior where females cut circular pieces from leaves to line nest cells. The species nests in pre-existing cavities in soil, sand, gravel, or rotting wood, and carries pollen on a scopa located on the underside of the abdomen rather than on the hind legs.
Megacina
Megacina is a genus of armoured harvestmen in the family Phalangodidae, established by Ubick & Briggs in 2008. The genus contains at least four described species, all found in western North America. These species are characterized by heavily sclerotized body armor typical of the family. The genus was erected based on morphological distinctions from related phalangodid genera.
Megahexura fulva
Tawny Dwarf Tarantula
Megahexura fulva is a small mygalomorph spider native to the western United States. It constructs an exposed sheet web with a funnel-shaped retreat in holes and crevices along ravine banks. The species is the sole member of the genus Megahexura, which was formerly placed in Mecicobothriidae but is now recognized in its own family, Megahexuridae. These spiders are among the smallest mygalomorphs, with body lengths typically under 10 mm.
Megalopsallus
Megalopsallus is a genus of plant bugs in the family Miridae, subfamily Phylinae. The genus was established by Knight in 1927 and contains at least 30 described species. Species in this genus are small, soft-bodied insects with the characteristic hemelytra of true bugs. The genus is primarily distributed in western North America, where species inhabit various plant associations.
Megalopsallus brendae
Megalopsallus brendae is a species of plant bug in the family Miridae, subfamily Phylinae, described by Schuh in 2000. It belongs to the tribe Hallodapini, a group of mirid bugs often associated with conifer hosts. The species is known from the western United States, specifically Arizona, California, and Nevada. Like other members of the genus Megalopsallus, it is likely associated with coniferous vegetation, though specific host plant records for this species are not documented in available sources.
Megalopsallus ephedrae
Megalopsallus ephedrae is a small plant bug in the family Miridae, subfamily Phylinae. Originally described by Knight in 1968 as Merinocapsus ephedrae, it was later transferred to Megalopsallus. The species is associated with Ephedra (Mormon tea) in arid regions of western North America. It is one of approximately 20 species in the genus Megalopsallus, which occurs primarily in western North America.
Megalopsallus humeralis
Megalopsallus humeralis is a species of plant bug in the family Miridae, originally described by Van Duzee in 1923 as Sthenarus humeralis. It belongs to the subfamily Phylinae, a group of small predatory or phytophagous true bugs commonly known as leaf bugs or plant bugs. The genus Megalopsallus comprises small mirids distributed primarily in western North America and adjacent regions of Mexico. This species has been documented from arid and semi-arid regions of the southwestern United States and northwestern Mexico.
Megalopsallus nigricaput
Megalopsallus nigricaput is a species of plant bug in the family Miridae, subfamily Phylinae, described by Randall T. Schuh in 2000. The species belongs to a genus of small, often inconspicuous mirids associated with coniferous host plants. It is known from the southwestern United States, specifically Arizona, Nevada, and Utah.
Megalopsallus pictipes
Megalopsallus pictipes is a species of plant bug in the family Miridae, originally described as Plagiognathus pictipes by Van Duzee in 1918. The species is distributed across the western United States and northern Mexico. Like other members of the genus Megalopsallus, it is a small predatory or plant-feeding true bug. The specific epithet 'pictipes' refers to the marked or painted legs, a characteristic feature of this species.
Megalopsallus teretis
Megalopsallus teretis is a species of plant bug in the family Miridae, described by Schuh in 2000. It belongs to the subfamily Phylinae, a group commonly known as leaf bugs or plant bugs that feed on plant sap. The species is known from arid and semi-arid regions of western North America.
Megandrena
encelia megandrena
Megandrena is a genus of mining bees in the family Andrenidae. The genus was established by Cockerell in 1927. It contains at least two described species: Megandrena enceliae and Megandrena mentzeliae. These bees are solitary ground-nesting bees characteristic of the Andrenidae family.
Megapenthes nigriventris
Megapenthes nigriventris is a species of click beetle (Elateridae) described by LeConte in 1884. It belongs to the genus Megapenthes, a group characterized by bioluminescent larvae commonly known as glow-worms. The species is known from western North America, with confirmed records from British Columbia, Canada. As with other members of its genus, the larvae are likely predatory and bioluminescent, though specific details for this species remain poorly documented.
Megapenthes turbulentus
Megapenthes turbulentus is a species of click beetle in the family Elateridae. The genus Megapenthes is characterized by large body size relative to other elaterids and distinctive antennal morphology. This species is documented from a limited number of observations, with most records originating from western North America.
Megaphorus
Megaphorus is a genus of robber flies (family Asilidae) containing approximately 18 described species. These predatory dipterans are found in western North America, particularly in arid and semi-arid regions. Adults are typically observed perching on vegetation, where they ambush flying insect prey. The genus was established by Bigot in 1857 and is classified within the tribe Apocleini of the subfamily Asilinae.
Megaphorus acrus
Hairy Robber Fly
Megaphorus acrus is a species of robber fly in the family Asilidae, first described by Curran in 1931. It belongs to a genus characterized by large, hairy-bodied predatory flies. The species is part of the diverse Asilidae family, whose members are known for their aggressive hunting behavior and distinctive physical appearance. Like other robber flies, M. acrus is presumed to be an aerial predator of other insects.
Megaphorus clausicellus
Megaphorus clausicellus is a species of robber fly (family Asilidae) originally described by Macquart in 1850 under the name Mallophora clausicella. Robber flies in this genus are predatory and typically associated with open, dry habitats. The species has been documented in the western United States, with observations from Nevada and other Great Basin localities. Like other members of the genus Megaphorus, adults are presumed to be aerial predators of other insects.
Megaphorus frustrus
Megaphorus frustrus is a species of robber fly in the family Asilidae, first described by Pritchard in 1935 under the basionym Mallophorina frustra. The genus Megaphorus belongs to the tribe Apocleini within the subfamily Asilinae. Robber flies in this genus are large, powerful predators known for their robust build and predatory habits. Information specifically documenting M. frustrus is sparse in the provided sources, though the genus is known from western North American arid and semi-arid habitats.
Megarcys subtruncata
Truncate Springfly
Megarcys subtruncata, commonly known as the truncate springfly, is a stonefly species in the family Perlodidae. It was described by Hanson in 1942. The species occurs in western North America, with documented records from British Columbia, California, Idaho, Montana, and Nevada. It belongs to a genus of predatory stoneflies typically associated with cold, well-oxygenated streams.
Megarthrus pictus
Megarthrus pictus is a rove beetle (Staphylinidae) endemic to western North America. It is distinguished from other Nearctic Megarthrus species by its bicolored elytra and angulate temples. The body is predominantly brownish yellow in coloration. It is the only Nearctic species in its genus exhibiting this combination of traits that is endemic to Western North America.
Melacoryphus lateralis
Charcoal Seed Bug, Black-and-red Seed Bug
Melacoryphus lateralis is a species of true bug in the family Lygaeidae, commonly known as the charcoal seed bug or black-and-red seed bug. Native to desert regions of western North America, this species is recognized by its distinctive black body fringed with red and gray coloration, resembling a dying ember. Populations are known to appear in large aggregations during late summer. The species is closely related to the small milkweed bug (Lygaeus kalmii) and shares similar coloration patterns with other lygaeid seed bugs.
Melanolophia imitata
Western Carpet, Green-striped Forest Looper
A spring-flying geometrid moth of western North America, notable for large, pale adults that occur in consistently high abundance. Adults fly during late evening and are less attracted to light than many moth species. The species shows minimal migratory movement but can form dense aggregations that create visible 'clouds' in forested habitats. Larvae are conifer-feeding loopers that prefer Douglas fir, Tsuga, and Abies.
Melanoplus bernardinae
Melanoplus bernardinae is a species of spur-throated grasshopper in the family Acrididae, described by Hebard in 1920. It belongs to the large genus Melanoplus, which contains many economically and ecologically significant grasshopper species in North America. The species is documented from California and is part of the western North American grasshopper fauna. Like other Melanoplus species, it is expected to exhibit typical grasshopper life history with egg diapause and nymphal development through multiple instars, though specific biological details remain poorly documented.
Melanoplus bivittatus bivittatus
Two-striped grasshopper
The two-striped grasshopper is a large, robust species widely distributed across North America. It is a polyphagous mixed-feeder that consumes both grasses and forbs, with a documented preference for forbs when available. This subspecies has been historically recognized but is now generally treated as a synonym of the species Melanoplus bivittatus. It is considered one of the most economically important grasshopper pests in western North America, particularly in Colorado where it attacks cereals, alfalfa, garden vegetables, and ornamental plantings.
Melanoplus bowditchi
Sagebrush Grasshopper
Melanoplus bowditchi, commonly known as the sagebrush grasshopper, is a medium-sized spurthroated grasshopper in the subfamily Melanoplinae. It is widely distributed across western North American grasslands where sagebrush is present. The species exhibits strong host plant specificity, feeding almost exclusively on sagebrush species, particularly silver sagebrush (Artemisia cana) and sand sagebrush (A. filifolia). Despite its potential to damage valuable forage plants, populations remain at low densities and significant economic impact has not been documented.