Forest-floor
Guides
Macrochilo louisiana
Louisiana Owlet, Louisiana Macrochilo, Louisiana Snout-moth
Macrochilo louisiana is a small litter moth in the family Erebidae, first described by William Trowbridge Merrifield Forbes in 1922. It is widely distributed across North America, ranging from Quebec and Maine south to Florida, west to Texas, and north to Alberta. Adults are active from June to September in northern populations and from February onward in southern populations. The species has a wingspan of 20–27 mm.
Mezira froeschneri
Mezira froeschneri is a species of flat bug in the family Aradidae, described in 1996 from North American specimens. Like other aradids, it has a highly flattened body adapted for living in tight spaces under bark. The species is known from only a handful of observations, reflecting the cryptic habits and difficulty of sampling this group.
Microedus fenderi
Microedus fenderi is a species of rove beetle in the family Staphylinidae, subfamily Omaliinae. It was described by Hatch in 1957 and is known from limited collection records in the Pacific Northwest region of North America. Like other members of the Omaliinae, it is a small beetle associated with forest floor habitats. Very little is known about its biology or ecology due to its rarity and the difficulty of sampling small staphylinid beetles.
Nannaria hardeni
Curt Harden's Twisted-Claw Millipede
Nannaria hardeni is a species of twisted-claw millipede described in 2021 from the Appalachian Mountains of the eastern United States. It belongs to the genus Nannaria, a group of forest-dwelling millipedes characterized by males having small, twisted and flattened claws on their anterior legs. The species was named in honor of Curt Harden, a millipede researcher who contributed significantly to the study of Appalachian xystodesmid millipedes. Like other members of its genus, N. hardeni plays a role as a decomposer in forest ecosystems.
Nannaria terricola
Loam-dwelling Twisted-Claw
Nannaria terricola is a flat-backed millipede in the family Xystodesmida, characterized by its loam-dwelling habits and the distinctive twisted, flattened claws on the anterior legs of males. The species is found in the Great Lakes region of the United States. Like other members of the genus Nannaria, it plays a role as a decomposer in forest ecosystems. The species was originally described as Fontaria terricola by Williams & Hefner in 1928 before being transferred to Nannaria.
Narceus
Narceus is a genus of large cylindrical millipedes in the family Spirobolidae native to eastern North America. The genus includes some of the largest millipedes in the region, with individuals reaching up to 12 cm in length. It comprises three to four recognized species, including two Florida endemics and a widespread species complex (N. americanus/annularis) spanning eastern Canada to the southern United States. These millipedes are significant decomposers in forest ecosystems and serve as intermediate hosts for certain parasites.
Neobolitobius varians
Neobolitobius varians is a species of rove beetle in the family Staphylinidae, subfamily Mycetoporinae. It was described by Hatch in 1957. The species is known from the Pacific Northwest region of North America, with records from British Columbia, Oregon, and Washington. As a member of the Mycetoporinae, it likely inhabits forest floor environments where these beetles are commonly found. Beyond taxonomic placement and geographic distribution, detailed biological information about this species remains sparse in the available literature.
Omus
Night-stalking Tiger Beetles
Omus is a genus of flightless, nocturnal tiger beetles (subfamily Cicindelinae) endemic to the west coast of North America. Members are uniformly dark-colored and characterized by reduced or absent hind wings, restricting them to ground-dwelling locomotion. The genus comprises at least five recognized species, including O. audouini, O. californicus, O. cazieri, O. dejeanii, and O. submetallicus. These beetles occupy diverse habitats from forest floors to upper salt marshes, with some species showing strong associations with specific plant communities.
flightlessnocturnalwest-coast-endemictiger-beetlesalt-marshforest-floorprolonged-copulationconservation-concernCanada-species-at-riskmorphological-character-displacementAmblycheiliniCicindelinaeCarabidaeColeopteralarval-burrowsDouglas-aster-indicator-speciesniche-partitioningmale-mandible-dimorphismsyn-copulatory-courtshiprain-shadow-habitatSierra-NevadaCascade-RangeCoast-RangeBritish-ColumbiaOregonCaliforniaWashingtonOmus californicus californicus
California Night-stalking Tiger Beetle
Omus californicus californicus is the nominate subspecies of the California night-stalking tiger beetle, a flightless, nocturnal carabid beetle endemic to California. Adults are active primarily in spring and early summer, with larvae occupying permanent burrows in soil. The species exhibits strong habitat fidelity to specific substrates and moisture conditions. Unlike diurnal tiger beetles in the genus Cicindela, Omus species are crepuscular to nocturnal hunters that do not rely on vision for prey capture.
Oreonetides
dwarf spiders
Oreonetides is a genus of dwarf spiders in the family Linyphiidae, first described by Embrik Strand in 1901. The genus contains 17 described species distributed across the Northern Hemisphere, with records from North America, Europe, Russia, and East Asia. Species occupy diverse habitats ranging from boreal and alpine regions to temperate forests. The type species, Oreonetides vaginatus, has the broadest distribution, spanning from North America across Eurasia to Japan.
Ortholasma
Ortholasma is a genus of harvestmen (Opiliones) in the family Nemastomatidae, containing five described species. The genus was established by Banks in 1894 and has been revised by Shear (2010). It is the type genus of the subfamily Ortholasmatinae. Species in this genus are small-bodied, short-legged dyspnoan harvestmen found in western North America.
Papusus
Papusus is a genus of minute rove beetles in the family Staphylinidae, subfamily Scydmaeninae, tribe Papusini. The genus was described by Casey in 1897 and is the sole member of its tribe. These beetles are among the smallest staphylinids and are associated with forest floor habitats. The genus is rarely encountered, with extremely limited observational records.
Paranonychidae
Paranonychid Harvestmen
Paranonychidae is a family of armored harvestmen (Opiliones) containing 9 genera and at least 28 described species. The family was established by Briggs in 1971 and is classified within the superfamily Travunioidea. Members are characterized by heavily sclerotized body armor, an adaptation that distinguishes them from many other harvestman families. The family has a predominantly Pacific Rim distribution, with genera found in Japan, western North America, and other regions.
Parcoblatta virginica
Virginia wood cockroach
Parcoblatta virginica, the Virginia wood cockroach, is a small woodland cockroach species measuring approximately 10 mm as an adult. It is native to deciduous forest habitats in eastern North America, where it inhabits leaf litter and decaying wood. The species exhibits strong sexual dimorphism in wing development and coloration. Unlike many cockroach species, it is not a household pest and cannot survive indoors due to low humidity requirements.
Paromalus
Paromalus is a genus of clown beetles in the family Histeridae, first described by Erichson in 1834. The genus comprises at least 60 described species distributed across multiple continents. These beetles are members of the subfamily Dendrophilinae and tribe Paromalini. They are small to medium-sized histerid beetles associated with various decaying organic substrates.
Phalaenophana pyramusalis
Dark-banded Owlet
Phalaenophana pyramusalis, commonly known as the dark-banded owlet, is a small moth in the family Erebidae. First described by Francis Walker in 1859, this species is widespread across eastern and central North America. Adults are active during summer months, with multiple generations per year in most of its range. The larvae are detritivores that feed on decaying leaf litter.
Phenopelopidae
Phenopelopidae is a family of oribatid mites comprising 4 genera and approximately 106 species. Adults are small (400–900 μm), typically dark brown to black, with distinctive flat blade-like lamellae and movable pteromorphs. Juveniles are soft-bodied, light brown, and possess plicate cuticle. These mites inhabit forest floor microhabitats and appear to be primarily fungal feeders.
Phlaeopterus cavicollis
Phlaeopterus cavicollis is a rove beetle in the subfamily Omaliinae, first described from the Pacific Northwest region. The species is associated with cool, moist montane and coastal environments across western North America. It belongs to a genus characterized by compact body forms and association with forest floor habitats. Available records suggest it occupies a relatively narrow geographic range compared to some congeners.
Phloeocharis californica
A small rove beetle endemic to California, described in 1980 from specimens collected in the state. As a member of the subfamily Phloeocharinae, it belongs to a group of staphylinids typically associated with forest floor habitats and decaying organic matter. The species is known from very few records, reflecting either genuine rarity or limited survey effort in its habitat.
Phloeonomus suffusus
Phloeonomus suffusus is a species of rove beetle in the family Staphylinidae, subfamily Omaliinae. It is documented from coastal regions of western North America, including British Columbia, Alaska, Washington, Oregon, and California. Like other members of its genus, it is likely associated with decaying plant matter and fungal habitats in moist forest environments. The species was described by Casey in 1893.
Platynus parmarginatus
Platynus parmarginatus is a species of ground beetle in the family Carabidae, first described by Hamilton in 1893. It belongs to the subfamily Platyninae, a group of predominantly nocturnal predatory beetles. The species is documented from the United States within North America. Like other Platynus species, it is likely a generalist predator inhabiting forest floor environments.
Porrhodites
Porrhodites is a genus of rove beetles (family Staphylinidae, subfamily Omaliinae) established by Kraatz in 1857. One species, Porrhodites inflatus, has been identified as a likely subnivium specialist—an arthropod adapted to the narrow airspace between soil and winter snowpack. These beetles appear to be active primarily during winter months and may enter dormancy during summer, representing a distinct life history strategy among temperate forest arthropods.
Pseudocistela brevis
Pseudocistela brevis is a species of darkling beetle (Tenebrionidae) first described by Thomas Say in 1824. The species is documented from eastern Canada, with confirmed records in New Brunswick, Ontario, and Quebec. Like other members of the genus Pseudocistela, it belongs to a group of small to medium-sized beetles associated with forest floor habitats and decaying organic matter.
Ptenothrix palmata
Ptenothrix palmata is a species of globular springtail in the family Dicyrtomidae, first described by Folsom in 1902. As a member of the order Symphypleona, it possesses the rounded, globular body form characteristic of this group. The species has been documented from Arctic, subarctic, and northern North American regions, including Pacific North America. Like other dicyrtomids, it inhabits moist microhabitats in forest floor environments.
Pterostichus caudicalis
Pterostichus caudicalis is a species of ground beetle in the family Carabidae, described by Thomas Say in 1823. It is classified as a woodland ground beetle and occurs in North America, with distribution records from Canada and the United States. Like other members of the genus Pterostichus, it is a predatory beetle that inhabits forest floor environments. The species is part of the diverse Pterostichinae subfamily, which contains numerous ground-dwelling carabid beetles.
Pterostichus circulosus
woodland ground beetle
Pterostichus circulosus is a species of ground beetle in the family Carabidae, described by Lindroth in 1966. It belongs to the large genus Pterostichus, which comprises numerous woodland-dwelling carabid beetles. The species is known from North America, with records from Alaska, Canada, and the United States. Like other members of its genus, it likely inhabits forest floor habitats where it functions as a generalist predator.
Pterostichus parasimilis
Pterostichus parasimilis is a species of woodland ground beetle in the family Carabidae, described by Ball in 1962. It is distributed across the Holarctic region, with records from Alaska, Canada, Russia, and the United States. Like other members of the genus Pterostichus, it is a ground-dwelling beetle typically associated with forest floor habitats.
Pterostichus strenuus
Rough-chested Blackclock
Pterostichus strenuus is a woodland ground beetle in the family Carabidae. The species has a Holarctic distribution, occurring in North America, Europe, and temperate Asia. It is one of many Pterostichus species adapted to forest floor habitats. Taxonomic authorities vary, with some sources listing Erichson (1837) and others Panzer (1796) or LeConte (1853).
Pterostichus stygicus
Woodland ground beetle
Pterostichus stygicus is a species of ground beetle in the family Carabidae, native to North America. It inhabits deciduous forest floor environments where it functions as a generalist predator. The species has been studied for its competitive interactions and intraguild predation relationships with centipedes, particularly Scolopocryptops sexspinosus.
Pycnoglypta campbelli
A small rove beetle in the subfamily Omaliinae, described from North American material in 1995. Known from scattered records across boreal and temperate regions of Canada and the northern United States. The genus Pycnoglypta contains few species and is characterized by compact body form and distinctive mouthpart structures.
Pycnoglypta fracta
Pycnoglypta fracta is a species of rove beetle in the family Staphylinidae, subfamily Omaliinae. It belongs to the tribe Omaliini, a group of small to medium-sized beetles commonly associated with decaying organic matter and forest floor habitats. The genus Pycnoglypta is part of the diverse staphylinid fauna of North America.
Quedius horni
Quedius horni is a species of rove beetle in the family Staphylinidae, described by Hatch in 1957. The species is known from the Pacific Northwest region of North America, with records from British Columbia, Oregon, and Washington. Like other members of the large genus Quedius, it belongs to a diverse group of predatory beetles commonly found in forest floor habitats and associated with decaying organic matter.
Renia flavipunctalis
Yellow-spotted Renia Moth, Yellow-dotted Renia, Even-lined Renia
Renia flavipunctalis is a litter moth in the family Erebidae, first described by Carl Geyer in 1832. It is a medium-sized moth with a wingspan of 26–31 mm, recognized by its yellow spotting pattern. The species occurs across eastern and central North America, from southern Canada to the southern United States. Adults are active during summer months, with northern populations having a single generation per year. Larvae feed on decaying organic matter, particularly dead leaves of deciduous trees.
Renia nemoralis
Chocolate Renia Moth, Tardy Renia
Renia nemoralis is a litter moth in the family Erebidae, first described by Barnes and McDunnough in 1918. It is commonly known as the Chocolate Renia Moth or Tardy Renia. The species occurs across the eastern and central United States, with adults active in late season. Larvae are detritivores, feeding on dead leaves and other organic matter.
Renia salusalis
Dotted Renia Moth, dotted renia
Renia salusalis, commonly known as the Dotted Renia Moth, is a litter moth in the family Erebidae. It was first described by Francis Walker in 1859. The species occurs across the eastern and central United States, where its larvae feed on detritus. Adults are active from late spring through early autumn, with generation timing varying by latitude.
Renia sobrialis
Sober Renia Moth, sober renia
Renia sobrialis, commonly known as the Sober Renia Moth, is a litter moth in the family Erebidae. First described by Francis Walker in 1859, this small moth is widespread in eastern North America. Adults are active from spring through late summer, and the larvae feed on decomposing leaf litter.
Rybaxis conjuncta
Rybaxis conjuncta is a small rove beetle in the subfamily Pselaphinae, commonly referred to as ant-loving beetles. It occurs across eastern and western North America, with records spanning from British Columbia to the Atlantic provinces of Canada and throughout the northeastern and north-central United States. The species is rarely encountered, with few documented observations.
Scaphinotus fissicollis
Cleft-collared Snail-eating Beetle
Scaphinotus fissicollis is a species of ground beetle in the family Carabidae, commonly known as the cleft-collared snail-eating beetle. It belongs to the tribe Cychrini, a group of large, specialized ground beetles often referred to as "snail hunters" due to their elongated head and mandibles adapted for extracting snails from their shells. Adults are brachypterous (short-winged), a trait common in this genus that reflects their ground-dwelling, non-flying lifestyle. The species occurs in the central United States.
Scaphinotus hubbardi
Hubbard's snail-eating beetle
Scaphinotus hubbardi, commonly known as Hubbard's snail-eating beetle, is a flightless ground beetle in the family Carabidae. The species is endemic to the southern Appalachian region of the eastern United States, where it inhabits coniferous forests. Adults are brachypterous (short-winged) and nocturnal, reflecting adaptations to their forest floor habitat. As a member of the tribe Cychrini, it is presumed to be a molluscivore, though direct dietary observations are limited.
Scolopocryptopidae
Scolopocryptopid Centipedes
Scolopocryptopidae is a family of blind centipedes in the order Scolopendromorpha, comprising more than 90 species. The family is distinguished from all other centipedes by having exactly 23 pairs of legs—a fixed trait that contrasts with the variable leg counts in other families. Members are eyeless and possess a distinctive gizzard with kinked, pineapple-shaped sieve projections. The family is most diverse in the Neotropical realm, with four recognized subfamilies: Ectonocryptopinae, Kethopinae, Newportiinae, and Scolopocryptopinae.
Scolopocryptops spinicaudus
Thorn-tailed Bark Centipede
Scolopocryptops spinicaudus is a centipede species first described by Wood in 1862. It belongs to the family Scolopocryptopidae within the order Scolopendromorpha. The species is known by the common name Thorn-tailed Bark Centipede and has been recorded across North America and parts of southern Asia including Japan. It is one of the more frequently observed centipedes in its range, with over 1,500 citizen science observations documented.
Scydmaeninae
Ant-like Stone Beetles, Scydmaenines
Scydmaeninae is a subfamily of minute rove beetles (family Staphylinidae) containing approximately 4,500 species in about 80 genera. Formerly treated as a distinct family, they were reclassified as a subfamily in 2009. Members are commonly known as ant-like stone beetles due to their constricted body shape resembling ants. The subfamily has a worldwide distribution and is divided into four extant supertribes: Cephenniitae, Mastigitae, Scydmaenitae, and the extinct fossil supertribe Hapsomelitae.
Siagonium stacesmithi
Siagonium stacesmithi is a rove beetle in the subfamily Piestinae, described by Hatch in 1957. The species is known from scattered records across northern North America, including western Canada, the Yukon, and parts of the western and northeastern United States. Like other members of Siagonium, it is a small, elongate beetle associated with forest floor habitats. It remains poorly known biologically, with only a handful of documented observations.
Stigmatomma pallipes
vampire ant, Eastern Dracula Ant
Stigmatomma pallipes, commonly known as the vampire ant or Eastern Dracula Ant, is a species of ant in the subfamily Amblyoponinae native to North America. It is one of three Stigmatomma species found on the continent. This species is notable for its small colony size and cryptic lifestyle, making it difficult to encounter in the field. The species is a specialized predator, though specific prey details are not well documented.
Tachinus crotchii
Crotch's Tachinus
Tachinus crotchii is a species of rove beetle in the family Staphylinidae, described by George Henry Horn in 1877. It is native to western North America, with documented occurrences in British Columbia, California, Oregon, and Washington. Like other members of the genus Tachinus, it is associated with forest floor habitats and decaying organic matter. The species is named after George Robert Crotch, a British entomologist who collected extensively in North America.
Tachyporus elegans
Tachyporus elegans is a species of rove beetle in the family Staphylinidae, subfamily Tachyporinae. The species was described by Horn in 1877. It is a small beetle with limited published information on its specific biology. Members of the genus Tachyporus are generally associated with decaying organic matter and are common in forest floor habitats.
Telephanus atricapillus
Black-headed Silvanid Beetle
Telephanus atricapillus is a small beetle in the family Silvanidae, commonly known as the Black-headed Silvanid Beetle. It is primarily known from northeastern North America, with records from Ontario, Québec, and Vermont. The species was described by Erichson in 1846 and is currently treated as a synonym of Telephanus velox in some taxonomic databases, though this synonymy may not be universally accepted. Like other silvanids, it is associated with stored products and forest floor habitats.
Temnothorax andrei
Andre's Acorn Ant
Temnothorax andrei is a small ant species in the genus Temnothorax, commonly known as Andre's Acorn Ant. The genus Temnothorax comprises over 350 species worldwide, with approximately 60 species known from North America. These ants are typically cavity-nesting, often inhabiting hollow nuts, acorns, or twigs. The species was first described by Emery in 1895 and is part of a genus known for its ecological importance in forest floor communities and its use in studies of social insect behavior, caste differentiation, and community ecology.
Trechus obtusus
Trechus obtusus is a ground beetle species in the family Carabidae, originally described from Europe and now established as an invasive species in Hawaii. It has been documented in large numbers in pitfall traps at Pu'u Maka'ala Natural Area Reserve on the island of Hawaii, where it may compete with or displace native carabid species. The species has a broad native distribution spanning North America, Europe, and Africa, with six recognized subspecies showing regional variation.
Usofila pacifica
Usofila pacifica is a small true spider in the family Telemidae, described by Banks in 1894. It is found along the west coast of North America, from the United States into Canada. The species inhabits moist forest floor environments, where it constructs minute, delicate webs.