Western-north-america
Guides
Sideridis fuscolutea
Sideridis fuscolutea is a noctuid moth species described by Smith in 1892. It occurs in western North America, with records from Alberta, Canada. The species belongs to the tribe Hadenini within the subfamily Noctuinae. Limited observational data exists for this species.
Sierolomorpha nigrescens
Sierolomorpha nigrescens is a species of parasitic wasp in the family Sierolomorphidae, described by Evans in 1961. It belongs to a small family of Hymenoptera with limited ecological documentation. The species has been recorded across western North America from Canada to the southwestern United States.
Sierraperla cora
Giant Roachfly, Italian Garlic
Sierraperla cora is a species of stonefly in the family Peltoperlidae, commonly known as the giant roachfly or Italian garlic. The species is characterized by its roach-like appearance, a trait shared by members of its family. It is native to western North America, with documented records from California, Nevada, and Oregon. The species was originally described as Peltoperla cora by Needham and Smith in 1916 before being transferred to the genus Sierraperla.
Sinodendron rugosum
Rugose Stag Beetle
Sinodendron rugosum, the rugose stag beetle, is a small stag beetle and the only member of its genus in western North America. Adults are black, 11–18 mm in length, with a distinctively pitted, rough-textured exoskeleton. Males possess a short median horn on the head, while females lack this structure or have only a small tubercle. The species develops in decaying wood of broadleaf trees and is active as an adult from spring through early summer.
Sitona californius
Sitona californius is a species of broad-nosed weevil in the family Curculionidae, native to western North America. The species has been documented as prey for the wasp Cerceris sextoides. Its name has frequently been misspelled as 'californicus' in scientific literature.
Skwala americana
American springfly
Skwala americana, commonly known as the American springfly, is a species of stonefly in the family Perlodidae. It is distributed across western North America, with records from Alberta, Arizona, British Columbia, California, Colorado, and other regions. As a member of the order Plecoptera, it has an aquatic larval stage and terrestrial adult stage, typical of stoneflies.
Skwala curvata
Curved Springfly
Skwala curvata, commonly known as the curved springfly, is a stonefly species in the family Perlodidae. It was described by Hanson in 1942 and is found in western North America.
Smerinthus astarte
Drowsy-eyed Sphinx
Smerinthus astarte is a sphinx moth in the family Sphingidae, currently treated as a synonym of Smerinthus cerisyi by most authorities. The species is known from western North America, with records from Alberta, Manitoba, Saskatchewan, and Vermont. The caterpillars feed on aspen, cottonwood, and willow foliage. Adults are nocturnal and possess distinctive eyespot patterns on the hindwings.
Smerinthus ophthalmica
Western Eyed Sphinx
Smerinthus ophthalmica is a sphinx moth (family Sphingidae) found in western North America. Originally described by Boisduval in 1855, it was long treated as a synonym or subspecies of S. cerisyi until elevated to full species status in 2010 based on morphological and genetic differences. It is distinguished from S. cerisyi by a pale brown phenotype, less scalloped forewing margins, smoother postmedian lines, sharper antemedian line angle, and narrower male antennal serrations. The species is known to lay eggs readily on illuminated sheets during moth-attracting events.
Sonoma parviceps
Sonoma parviceps is a small rove beetle in the family Staphylinidae, specifically within the ant-loving beetle subfamily Pselaphinae. The species was first described by Mäklin in 1852 under the name Euplectus parviceps. It is distributed across western North America, with records from Alaska through British Columbia and south to California. As a member of Pselaphinae, it is presumed to be associated with ant colonies, though specific ecological details remain poorly documented.
Soyedina nevadensis
Nevada Forestfly
Soyedina nevadensis is a species of stonefly in the family Nemouridae, commonly known as the Nevada Forestfly. It was described by Claassen in 1923. The species belongs to the order Plecoptera, a group of aquatic insects whose nymphs typically inhabit cold, clean streams.
Spaelotis bicava
western w-marked cutworm
Spaelotis bicava is a species of cutworm moth in the family Noctuidae, described by Lafontaine in 1998. It is commonly known as the western w-marked cutworm. The species is distributed across North America, with confirmed records from the Canadian provinces of Alberta, Manitoba, and Saskatchewan. Its MONA/Hodges number is 10926.1.
Sparganothis senecionana
Sparganothis senecionana is a tortricid moth species distributed across western North America from British Columbia to Mexico and eastward to Colorado. Adults are active from April to August with one generation per year. The species exhibits broad polyphagy, with larvae feeding on flowers of diverse host plants spanning multiple families including Asteraceae, Fabaceae, Lamiaceae, and conifers.
Speleonychia sengeri
Speleonychia sengeri is a troglobitic harvestman (order Opiliones) described by Briggs in 1974. The genus Speleonychia is endemic to cave systems in western North America. As a member of the family Cladonychiidae, this species belongs to a group of small, eyeless, pale-colored arachnids adapted to subterranean environments. Very few observations exist—only five records on iNaturalist—reflecting its restricted habitat and cryptic lifestyle.
Speyeria callippe callippe
Callippe Fritillary
Speyeria callippe callippe is a subspecies of fritillary butterfly in the family Nymphalidae. It belongs to the greater fritillary genus Speyeria, which includes species known for their close ecological association with violets (Viola spp.) as larval host plants. The subspecies is native to western North America. Related Speyeria species have been demonstrated to rely primarily on visual cues for navigation to suitable habitat patches.
Speyeria cybele letona
Great Spangled Fritillary (western subspecies)
Speyeria cybele letona is a western North American subspecies of the great spangled fritillary, a large brush-footed butterfly with a wingspan of 2.25 to 4 inches. Research on Speyeria cybele indicates that visual perception is the primary sense used for navigation to suitable habitat patches, with individuals capable of detecting and navigating to target islands from distances up to 60 meters. The subspecies exhibits the orange-brown coloration typical of western populations of this species, in contrast to the more orange eastern populations.
Speyeria egleis
Great Basin fritillary, egleis fritillary
Speyeria egleis is a medium-sized fritillary butterfly native to western North America. Adults are active from late June through August and inhabit mountain meadows, forest openings, and exposed rocky ridges. The species exhibits strong fidelity to Viola species as larval host plants. Multiple subspecies have been described across its range, reflecting geographic variation in morphology and distribution.
Speyeria hesperis irene
Speyeria hesperis irene is a subspecies of the Hesperis fritillary, a North American butterfly in the family Nymphalidae. It belongs to the greater fritillary group within the genus Speyeria, which are medium to large butterflies with characteristic silver spots on the undersides of their wings. The subspecies designation indicates geographic variation within the broader species S. hesperis. Like other Speyeria species, it is associated with violets (Viola spp.) as larval host plants. GBIF currently lists this taxon as a synonym of Speyeria atlantis, reflecting ongoing taxonomic revision in this complex group.
Speyeria hesperis ratonensis
Speyeria hesperis ratonensis is a subspecies of fritillary butterfly described by Scott in 1981. It belongs to the genus Speyeria, commonly known as greater fritillaries, which are characterized by their orange and black wing patterns and violet-feeding larvae. The subspecies epithet "ratonensis" suggests an association with Raton, New Mexico or the Raton Mesa region. Like other Speyeria species, it is expected to exhibit visual-based navigation to locate suitable habitat patches, though specific studies on this subspecies are lacking.
Speyeria hydaspe
Hydaspe fritillary
Speyeria hydaspe, the Hydaspe fritillary, is a small orange-brown butterfly of western North America. Adults are active from July through September and feed on flower nectar. The species is distinguished from similar fritillaries by its smooth, even postmedian spotband. A single brood occurs annually. Caterpillars feed on violets, particularly Viola glabella.
Speyeria mormonia mormonia
Mormon Fritillary
Speyeria mormonia mormonia is a montane butterfly subspecies found in western North America. Research indicates adults exhibit compensatory feeding behavior to offset energy costs of increased flight activity. Females demonstrate higher early-life fecundity under conditions of abundant food resources, with metabolic rates declining with age. The subspecies shows sexual dimorphism in demographic parameters including survival patterns correlated with weather conditions.
Sphaerites politus
polite beetle, American False Clown Beetle
Sphaerites politus is a species of false clown beetle in the family Sphaeritidae, a small family of beetles closely related to clown beetles (Histeridae). The species was described by Mannerheim in 1846 and occurs in western North America from Alaska south through western Canada and the western United States. It is one of only two species in the genus Sphaerites found in North America.
Sphaerophoria sulphuripes
Forked Globetail
Sphaerophoria sulphuripes, commonly known as the forked globetail, is a species of syrphid fly native to western North America. As a member of the hover fly family Syrphidae, it is frequently observed visiting flowers for nectar and pollen. The species is part of a genus known for its distinctive globular abdomen shape. Adults are often mistaken for bees or wasps due to their yellow and black coloration, a form of protective mimicry common in this family.
Sphaeropthalma amphion
Sphaeropthalma amphion is a species of velvet ant in the family Mutillidae, first described by Fox in 1899. Like other members of this genus, it is a parasitoid wasp with wingless females and winged males. The species is part of a diverse group of solitary wasps known for their aposematic coloration and painful stings. Very little specific information is available for this particular species.
Sphaeropthalma arota
velvet ant
Sphaeropthalma arota is a velvet ant (family Mutillidae) native to western North America. Phylogeographic studies indicate this name represents a cryptic species complex comprising four genetically distinct lineages that cannot be distinguished by current morphological methods. The species is adapted to arid environments, with diversification events linked to late Neogene mountain building and aridification in western North America. Like other mutillids, females are wingless and wasp-like in appearance, while males possess wings.
Sphaeropthalma luiseno
Sphaeropthalma luiseno is a species of velvet ant in the family Mutillidae. Like other members of this genus, it is a wingless female wasp that parasitizes the nests of other wasps. The species is part of a diverse genus of velvet ants found primarily in western North America.
Sphaeropthalma marpesia
Sphaeropthalma marpesia is a species of velvet ant in the family Mutillidae, described by Blake in 1879. The species is distributed across the western and southwestern United States and Mexico. Velvet ants in this genus are solitary wasps with wingless females and winged males. The specific epithet 'marpesia' references the Amazon queen Marpesia, a namesake shared with the daggerwing butterflies of genus Marpesia.
Sphaeropthalma mendica
velvet ant
Sphaeropthalma mendica is a desert-adapted velvet ant (family Mutillidae) native to western North America. It belongs to the S. unicolor species-complex, which includes both Mediterranean-adapted and desert-adapted species. Phylogeographic studies indicate that S. mendica diverged from its sister species S. unicolor during the early Pleistocene, with subsequent population structuring among desert populations. Like all velvet ants, females are wingless and possess a potent sting, while males are winged.
Sphaeropthalma orestes
Sphaeropthalma orestes is a species of velvet ant (family Mutillidae) described by Fox in 1899. The species is found in the western United States and Mexico. Like all velvet ants, it is a solitary wasp with wingless females and winged males. The species belongs to a genus characterized by compact, often brightly colored bodies with dense pubescence.
Spharagemon campestris
Campestral Grasshopper, McNeill campestral grasshopper
Spharagemon campestris is a band-winged grasshopper in the family Acrididae, subfamily Oedipodinae. The species was originally described as Trimerotropis campestris by McNeill in 1901 and later transferred to the genus Spharagemon. It is recorded from western North America including Wyoming and British Columbia. As a member of the Oedipodinae, it possesses enlarged hind femora adapted for jumping and typically exhibits banded wing patterns characteristic of this subfamily.
Spharagemon equale
Say's grasshopper, orange-legged grasshopper
Spharagemon equale, commonly known as Say's grasshopper or the orange-legged grasshopper, is a relatively large band-winged grasshopper species in the family Acrididae. It is widely distributed across the grasslands of western North America, inhabiting tallgrass, mixedgrass, shortgrass, bunchgrass, and desert prairies, as well as shrub-grass communities of the Great Basin. The species is characterized by its orange hind tibiae, which give it its common name, and distinctive banded hindwings. It is a polyphagous feeder on grasses and forbs, typically occurring at low densities in rangeland assemblages.
Spharagemon equale equale
Orangelegged Grasshopper, Say's Grasshopper
Spharagemon equale equale is a relatively large bandwinged grasshopper native to western North American grasslands. Adults are distinguished by orange hind tibiae and orange inner hind femora marked with dark bands. The subspecies is polyphagous, feeding on diverse grasses and forbs with documented regional variation in plant preferences. It is a subdominant member of rangeland grasshopper assemblages, typically occurring at low densities with minor economic impact except during rare population increases. The species is a strong flier with long wings extending beyond the abdomen, and both sexes crepitate in flight.
Sphecius grandis
Western Cicada Killer, Western Cicada-killer Wasp
Sphecius grandis is a large, solitary wasp endemic to western North America, ranging from Central America through Mexico to the Western United States. Females construct burrows in sandy, well-drained soils, often forming nest aggregations with hundreds of individual nests. They provision underground cells with paralyzed cicadas (primarily Tibicen duryi, T. dealbata, and T. parallela) as food for their larvae. The species exhibits pronounced sexual dimorphism: females are larger (forewing length 2.5–3 cm, mass ~256 mg) and live approximately one year, while smaller males (~95 mg) emerge earlier, live only a few days, and engage in aggressive territorial competition for mating access. Activity is concentrated in July and early August, synchronized with cicada emergence. Despite their large size and formidable appearance, they are not habitually aggressive toward humans.
Sphex tepanecus
Sphex tepanecus is a species of thread-waisted digger wasp in the family Sphecidae. It is a large solitary wasp known from the western United States, with records from Arizona, Colorado, and potentially Idaho. Like other members of the genus Sphex, it constructs subterranean nests and provisions them with paralyzed prey for its larvae. The species was first described by de Saussure in 1867.
Sphinx perelegans
elegant sphinx
Sphinx perelegans, the elegant sphinx, is a large hawkmoth species native to western North America. Adults are active from April to September and are nocturnal, attracted to light. The larvae feed on a variety of woody plants including Arctostaphylos, Prunus, and Symphoricarpos species.
Sphinx sequoiae
Sequoia Sphinx
Sphinx sequoiae is a small sphinx moth native to western North America, ranging from Oregon through California, Nevada, Utah, Arizona, and into northern Baja California. It is the smallest species in its genus besides Sphinx dollii, with which it is sometimes confused despite occupying different geographic ranges. The species completes one generation annually, with adults active from May through August.
Sphinx vashti
Vashti Sphinx
Sphinx vashti, the Vashti sphinx, is a moth in the family Sphingidae. It is found in western North America from British Columbia to Manitoba and south to southern California, Nevada, Arizona, New Mexico, and western Texas. The species exhibits highly variable forewing coloration ranging from pale to very dark gray, with distinctive black dashes and a black hindwing featuring white bands. It has one brood per year.
Sphiximorpha durani
Duran's wasp fly
Sphiximorpha durani is a hoverfly species in the family Syrphidae, native to the western United States. The species exhibits Batesian mimicry of wasps, a characteristic feature of its tribe Cerioidini. It was described by Davidson in 1925 and is known by the common name Duran's wasp fly.
Spilomyia citima
Western Hornet Fly
Spilomyia citima, commonly known as the Western Hornet Fly, is a rare species of syrphid hoverfly first described by Vockeroth in 1958. It belongs to a genus renowned for exceptional mimicry of yellowjacket wasps, employing visual, behavioral, and acoustic deception. The species has been documented in Canada and the United States, though records remain sparse.
Spilomyia crandalli
Crandall's Hornet Fly
Spilomyia crandalli is a rare species of syrphid fly described by Curran in 1951. Adults are known as flower flies and are commonly found on flowers, where they feed on nectar and pollen. The species belongs to a genus renowned for exceptional wasp mimicry, including visual, behavioral, and acoustic deception of yellowjackets. Larvae are adapted to moist environments such as tree rot holes.
Spilomyia interrupta
Interrupted Hornet Fly
Spilomyia interrupta, commonly known as the Interrupted Hornet Fly, is a species of hoverfly in the family Syrphidae. First described by Williston in 1882, this uncommon species is native to western North America, particularly along the California coast. Like other members of the genus Spilomyia, it exhibits remarkable mimicry of yellowjacket wasps, including similar coloration, body shape, and even wingbeat frequency. Adults visit flowers for nectar and pollen, while larvae develop in moist tree rot holes.
Spilosoma vagans
Wandering Tiger Moth, Wandering Diacrisia
Spilosoma vagans is a tiger moth in the family Erebidae, described by Boisduval in 1852. It occurs in western North America from southern California north to southern British Columbia and southwestern Alberta. Adults fly from late April through early August in dry forest habitats. The larvae feed on herbaceous plants.
Spodoptera praefica
Western Yellow-striped Armyworm, Western Yellow-striped Armyworm Moth
Spodoptera praefica, the western yellow-striped armyworm, is a noctuid moth native to western North America. The species has two adult flight periods annually, occurring in early spring and late summer. Larvae are black with yellow stripes and feed on herbaceous plants including several agricultural crops. The species is considered a high risk for invasion into the European and Mediterranean region but is currently absent from that area.
Stegea salutalis
Western Stegea
Stegea salutalis is a small crambid moth native to western North America, ranging from British Columbia to northwestern Mexico. Adults show considerable geographic and seasonal variation in appearance. The species has a wingspan of approximately 18 mm and produces two generations per year.
Steiroxys trilineatus
Three-lined Shieldback, Three-lined Camel Cricket
Steiroxys trilineatus is a shieldback katydid native to western North America, recognized by the three pale longitudinal stripes running along its dorsal surface. This flightless, ground-dwelling species inhabits grassland and sagebrush steppe ecosystems, where it occupies a cryptic lifestyle among vegetation and litter. Adults are active during summer months, with males producing songs via tegminal stridulation to attract mates. The species has been documented from the Great Basin through the Rocky Mountain region, with populations adapted to semi-arid conditions.
Steniolia
sand wasps
Steniolia is a genus of solitary sand wasps in the family Crabronidae, containing approximately 15 described species. All North American species are western in distribution, with four species extending only as far north as Mexico. Females are fossorial, constructing single-celled burrows in dry, powdery soil to provision with paralyzed flies. The genus is notable for ornate coloration, elongated mouthparts adapted for nectar feeding, and distinctive nightly sleeping clusters formed by both sexes.
Steniolia elegans
sand wasp
Steniolia elegans is a solitary sand wasp in the family Crabronidae. Females dig burrows in dry, powdery soil and provision them with paralyzed flies for their single offspring. The species exhibits progressive provisioning, with females repeatedly hunting and delivering prey throughout larval development. Both sexes form dense, spherical sleeping clusters at night where mating occurs.
Stenocolus
Stenocolus is a monotypic genus of beetles in the family Eulichadidae. The sole described species, S. scutellaris, is a forest stream beetle found in western North America. The genus belongs to a small family of aquatic or semi-aquatic beetles associated with running water habitats.
Stenocorus nubifer
Stenocorus nubifer is a species of longhorn beetle (family Cerambycidae) distributed across western North America. The species exhibits variable coloration, with individuals being either black or brown. As a member of the subfamily Lepturinae, it belongs to a group commonly known as flower longhorns, though specific floral associations for this species remain undocumented.
Stenodema pilosipes
Stenodema pilosipes is a species of plant bug in the family Miridae, described by Kelton in 1961. It belongs to a genus of grass-feeding mirids. The species is documented from western North America.