Nearctic
Guides
Marathyssa nr-inficita
Marathyssa nr-inficita is a Nearctic moth species in the family Noctuidae, subfamily Euteliinae. The specific epithet "nr-inficita" indicates this taxon is near or related to Marathyssa inficita but has not been formally described or is of uncertain taxonomic status. Members of the genus Marathyssa are generally small to medium-sized noctuid moths with distinctive wing patterns. The species has been documented in North American records, though detailed biological information remains limited.
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 fraxinicola
Marmara fraxinicola is a micro-moth in the family Gracillariidae, first described by Braun in 1922. The species is known from northeastern North America, with records from Québec, Canada, and the U.S. states of Ohio, Vermont, and New York. It has one generation per year and is a specialist stem-miner of ash trees (Fraxinus species).
Maso sundevalli
Maso sundevalli is a species of sheet-web weaving spider in the family Linyphiidae, first described by Westring in 1851. Originally placed in the genus Erigone, it was later transferred to Maso. The species has a broad distribution across the Northern Hemisphere, including Europe, Asia, and North America. Like other linyphiids, it constructs flat sheet webs with a retreat and captures small flying insects.
Mastogenius castlei
Mastogenius castlei is a species of metallic wood-boring beetle in the family Buprestidae, described by Champlain and Knull in 1922. The genus Mastogenius comprises some of the smallest buprestids, with adults measuring approximately 2 mm in length. Very little specific information is documented for this species; most knowledge of the genus derives from congeneric species.
Mastophora leucabulba
Mastophora leucabulba is a bolas spider in the orb-weaver family Araneidae. Adult females hunt using a single sticky silk droplet suspended from a dragline rather than building an orb web. Males and juvenile females lack this specialized hunting method and capture prey directly with their legs. The species occurs from the United States to Honduras.
Matriella teresa
Matriella teresa is a species of spiny crawler mayfly in the family Ephemerellidae, described by Traver in 1934. It belongs to a genus of mayflies found in North America. As with other members of Ephemerellidae, it likely inhabits freshwater streams and rivers during its aquatic nymphal stage.
Mecaphesa celer
swift crab spider
Mecaphesa celer is a crab spider in the family Thomisidae, commonly known as the swift crab spider. It is distributed across much of North and Central America. The species exhibits extreme sexual size dimorphism, with females more than twice the size of males. It is a sit-and-wait predator that hunts on flowers and upper plant parts, and has been studied for its population genetics in fragmented volcanic habitats.
Mecynogea
basilica spiders
Mecynogea is a genus of orb-weaver spiders in the family Araneidae, first described by Eugène Simon in 1903. The genus contains nine species distributed across the Americas, from the United States to Argentina. The name derives from Greek words meaning "to lengthen" and "earth." Members of this genus are commonly known as basilica spiders.
Mecynogea lemniscata
Basilica Orbweaver
Mecynogea lemniscata, commonly known as the basilica orbweaver, is a species of orb-weaving spider in the family Araneidae. It occurs across a broad geographic range from the United States to Argentina. Females are generalist predators that employ orb-web hunting strategies. Research has documented sixteen distinct behavioral acts during prey capture, with sequences varying according to prey type.
Medetera bistriata
Medetera bistriata is a species of long-legged fly in the family Dolichopodidae. Adults are commonly observed on tree trunks in pine forests, where they adopt a characteristic tiptoe posture. The larvae are specialized predators of bark beetles, particularly species in the genera Dendroctonus and Ips. The species is recognized as an important biological control agent of the southern pine beetle (Dendroctonus frontalis).
Megacephalini
Big-headed Tiger Beetles
Megacephalini is a tribe of tiger beetles (family Cicindelidae) characterized by notably enlarged heads relative to body size. The tribe includes approximately seven described species across at least two genera, with Megacephala and Tetracha being the most prominent. Members are distributed across the Americas, with some species showing strong habitat specialization for saline or alkaline environments. The taxonomy of this group has undergone recent revision, with former subgenera of Tetracha elevated to generic status.
Megaderus
Megaderus is a genus of long-horned beetles (Cerambycidae) first described by Dejean in 1821. The genus contains at least two described species: Megaderus bifasciatus, distributed across North and Central America, and Megaderus stigma, found in South and Central America. Both species are classified within the subfamily Cerambycinae and tribe Trachyderini. The genus is represented by 352 observations on iNaturalist, indicating moderate documentation in citizen science records.
Megalepthyphantes nebulosus
Megalepthyphantes nebulosus is a species of sheetweb spider in the family Linyphiidae. It is one of the more widely distributed linyphiid species, occurring across North America and Eurasia. The species was first described by Sundevall in 1830. Like other members of its family, it constructs sheet webs for prey capture. The specific epithet 'nebulosus' refers to the cloudy or nebulous appearance, likely describing coloration or pattern.
Megalopinus rufipes
Megalopinus rufipes is a species of rove beetle in the family Staphylinidae, subfamily Megalopsidiinae. It is one of the largest rove beetles, with adults reaching approximately 20 mm in length. The species is distinguished by its reddish-orange legs, which contrast with its dark body. It has been recorded from the southeastern United States through Mexico, with some unconfirmed reports from Central and South America.
Megalopsallus nicholi
Megalopsallus nicholi is a species of plant bug in the family Miridae, subfamily Phylinae. It was described by Knight in 1968. The species is known from the southwestern United States and northern Mexico. As a member of the genus Megalopsallus, it belongs to a group of small, often inconspicuous mirids associated with coniferous vegetation.
Megaphorus laphroides
Megaphorus laphroides is a species of robber fly (family Asilidae) described by Wiedemann in 1828. It belongs to the tribe Apocleini within the subfamily Asilinae. The genus Megaphorus contains species of medium to large predatory flies that hunt other insects. Like other robber flies, M. laphroides likely exhibits the characteristic predatory behavior of ambushing prey in flight using its strong legs and piercing mouthparts.
Megasoma sleeperi
Sleeper's Elephant Beetle
Megasoma sleeperi is a species of rhinoceros beetle in the family Scarabaeidae. It is endemic to the Algodones Dunes of southeastern California and adjacent areas of southwestern Arizona and northwestern Mexico. Like other members of the genus Megasoma, it is among the largest beetles in North America. Males possess prominent horns used in combat with other males. The species was described by Hardy in 1972 and is named in honor of collector R. C. Sleeper.
Megatoma
Megatoma is a genus of dermestid beetles (family Dermestidae) distributed across the Palearctic, Near East, and Nearctic regions. The genus contains approximately 23 described species, including the well-studied Megatoma undata (Linnaeus, 1758). Species within this genus are associated with stored products and natural habitats where they feed on dried organic matter. Larval stages have been documented in detail for some species, showing characteristic dermestid morphology with specialized setae.
Melacoryphus admirabilis
Admirable Seed Bug
Melacoryphus admirabilis is a seed bug in the family Lygaeidae, native to the Nearctic region of North America. The species is closely related to other soapberry bugs and shares ecological associations with plants in the family Sapindaceae. It occurs in the southwestern United States and Mexico, typically in warm, arid habitats. Like other members of its genus, it feeds on seeds and plant fluids. The species is occasionally encountered in large aggregations.
Melanaethus uhleri
Melanaethus uhleri is a species of burrowing bug in the family Cydnidae, order Hemiptera. The genus Melanaethus belongs to the burrowing bug family Cydnidae, a group of true bugs adapted for digging in soil and associated with roots of plants. Species in this genus are typically found in the Nearctic region. As with other cydnids, M. uhleri likely exhibits subterranean habits and feeds on plant roots, though specific biological details for this species remain poorly documented in the accessible literature.
Melanocanthon
Melanocanthon is a genus of dung beetles in the family Scarabaeidae, established by Halffter in 1958. The genus contains at least four described species distributed in the Nearctic region. Unlike many scarabaeine dung beetles, at least one species (M. nigricornis) has been documented utilizing fungus and carrion rather than dung as primary food resources.
Melanocanthon nigricornis
A small dung beetle species in the family Scarabaeidae, native to central North America. The species name "nigricornis" refers to its black antennae. It inhabits grassland and prairie ecosystems where it contributes to nutrient cycling through dung burial. The species has been documented across a broad swath of the central United States and extends into northern Mexico.
Melanoliarus altanatus
Melanoliarus altanatus is a species of planthopper in the family Cixiidae, first described by Caldwell in 1951 as Sonorium altanatum and later transferred to the genus Melanoliarus. The species belongs to the tribe Pentastirini within the subfamily Cixiinae. Cixiid planthoppers are small to medium-sized insects characterized by their membranous wings and association with plant hosts, though specific biological details for this species remain poorly documented.
Melanoliarus arizonensis
Melanoliarus arizonensis is a species of planthopper in the family Cixiidae, first described by Mead and Kramer in 1982. As a member of the order Hemiptera, it possesses piercing-sucking mouthparts typical of true bugs. The genus Melanoliarus belongs to the planthopper infraorder Fulgoromorpha, a group of sap-feeding insects often associated with woody plants. The specific epithet "arizonensis" indicates the species was described from or is associated with Arizona. Like other cixiids, it likely has brachypterous (short-winged) or macropterous (long-winged) forms, though specific morphological details for this species remain poorly documented in available sources.
Melanoliarus chuliotus
Melanoliarus chuliotus is a species of planthopper in the family Cixiidae, first described by Ball in 1934 under the genus Oliarus. The species was later transferred to Melanoliarus, a genus of small to medium-sized cixiid planthoppers distributed primarily in the Neotropical and Nearctic regions. Like other members of Cixiidae, it is presumed to have piercing-sucking mouthparts and a life cycle involving root-feeding nymphal stages. Published biological data for this specific species are extremely limited.
Melanolophiini
Melanolophiini is a tribe of geometrid moths within the subfamily Ennominae. Members of this tribe are primarily distributed in the Nearctic and Neotropical regions. The group contains several genera, including the type genus Melanolophia. These moths are generally small to medium-sized with relatively subdued coloration compared to some other geometrid groups.
Melasinae
false click beetles
Melasinae is a subfamily of false click beetles in the family Eucnemidae, containing approximately 15 genera and at least 30 described species. The subfamily includes several tribes: Calyptocerini, Ceballosmelasini, Dirhagini, Epiphanini, Hylocharini, Melasini, Neocharini, and Xylobiini. Genera within Melasinae include Melasis, Hylis, Epiphanis, Xylophilus, and Isorhipis. Some species, such as Hylis olexai, have established adventive populations in the Nearctic region after originating from Western and Central Europe.
Meligramma triangulifera
Variable Roundtail
Meligramma triangulifera is a hoverfly species first described from Europe in 1843. Taxonomic revisions have synonymized several Nearctic species names (M. tenuis, M. cincta) under this species, expanding its recognized range. Identification keys exist for both adult and puparial stages. The species has been recorded across Europe and the Nearctic region.
Melikaiella ostensackeni
Melikaiella ostensackeni is a species of oak gallwasp described in 2014 from the United States. It belongs to the genus Melikaiella, established to accommodate species previously placed in Callirhytis and Cynips. As a cynipid wasp, it induces gall formation on oak hosts. The species is one of twelve currently recognized in the genus.
Melinopterus consentaneus
Melinopterus consentaneus is a species of scarab beetle in the family Scarabaeidae. The species was described by LeConte in 1850. It is currently treated as a synonym of Flaviellus consentaneus. Records indicate occurrence in prairie and grassland regions of central North America.
Melipotis acontioides
Royal Poinciana Moth
Melipotis acontioides, commonly known as the Royal Poinciana Moth, is a nocturnal moth in the family Erebidae. The species was first described by Achille Guenée in 1852. It has a broad distribution spanning the southern United States, Mexico, Central and South America, and the Caribbean, with a distinct subspecies endemic to the Galápagos Islands. The larvae are specialized feeders on certain leguminous trees.
Melipotis cellaris
Cellar Melipotis Moth, Cellar Graphic
Melipotis cellaris is a moth in the family Erebidae with a broad Neotropical and southern Nearctic distribution. Adults have a wingspan of 35-37 mm and are active year-round in at least part of their range. The species has been recorded from the southern United States through Mexico, Central America, the Caribbean, and into South America.
Melitara texana
Texas snout moth
Melitara texana is a species of snout moth in the family Pyralidae, described by Herbert H. Neunzig in 1997. The species is known from southern Texas and adjacent Mexico. Its larvae are specialized feeders on Opuntia lindheimeri var. lindheimeri, a prickly pear cactus species.
Melitoma
chimney bees
Melitoma is a genus of solitary bees commonly known as chimney bees, comprising approximately 11-13 described species. Members of this genus are classified within the family Apidae, tribe Emphorini, and are characterized by their distinctive nesting behavior involving the construction of chimney-like turrets at nest entrances. The genus occurs in the Nearctic and Neotropical regions, with species documented from North America through Central and South America.
Melymacra
Melymacra is a genus of plant bugs in the family Miridae, established by Schwartz in 2004. It belongs to the diverse infraorder Cimicomorpha within the true bugs (Heteroptera). The genus is poorly documented in scientific literature, with minimal published information on its species composition, biology, and ecology. Available records indicate extremely few observations, suggesting either genuine rarity, cryptic habits, or undercollection.
Memnonia panzeri
Memnonia panzeri is a species of leafhopper described by Hamilton in 2000. It belongs to the tribe Hecalini within the subfamily Deltocephalinae, a diverse group of grass-feeding leafhoppers. The species is known from the north-central United States and southern Canada. As with other members of its genus and tribe, it is presumed to be associated with grassland habitats.
Mendidius aculeatus
Mendidius aculeatus is a species of dung beetle in the family Scarabaeidae, subfamily Aphodiinae. It was described by Robinson in 1940. The species is known from scattered records in the southwestern United States (California, Nevada, Utah) and northern Mexico (Chihuahua). Like other members of the genus Mendidius, it is presumed to be associated with dung and decaying organic matter, though specific biological details remain poorly documented.
Menkeleon
Menkeleon is a genus of antlions in the family Myrmeleontidae, established by Stange in 1970. The genus contains a single described species, Menkeleon bellulus, which occurs in the Western United States and Mexico. Antlions in this family are characterized by their predatory larval stage, which typically construct pit traps to capture prey.
Menoeceus
Menoeceus is a genus of darkling beetles in the family Tenebrionidae, described by Champion in 1888. The genus is distributed in the Nearctic and Neotropical regions. As a tenebrionid genus, it belongs to a large and diverse family of beetles commonly associated with arid and semi-arid environments. The genus name derives from Greek mythology, though this etymological origin has no biological significance.
Meristopsis melanosteptos
Meristopsis melanosteptos is a species of planthopper in the family Delphacidae, described from specimens collected in Florida and Oaxaca, Mexico. The species belongs to a genus of small delphacid planthoppers characterized by reduced wing venation and distinctive male genitalia. It was formally described in 2012 as part of a taxonomic revision of New World delphacine genera. Like other members of Delphacidae, it is presumed to feed on monocotyledonous plants, though specific host associations remain undocumented.
Mermessus maculatus
dwarf spider
Mermessus maculatus is a dwarf spider in the family Linyphiidae, first described by Banks in 1892. The species exhibits a broad Nearctic distribution spanning from Canada to Guatemala, with additional records from the Commander Islands in Russia. As a member of the sheet-web weaving spiders, it belongs to a large family of small-bodied arachnids characterized by their distinctive web architecture.
Merogyrus
Merogyrus is a genus of scarab beetles in the family Scarabaeidae, subfamily Aphodiinae, described by Gordon and Skelley in 2007. It belongs to the tribe Aphodiini, a group commonly known as small dung beetles. The genus is currently known from the Nearctic region. As a recently described and poorly documented genus, few species-level details have been published.
Merogyrus rotundiceps
Merogyrus rotundiceps is a species of dung beetle in the family Scarabaeidae, subfamily Aphodiinae. Described by Fall in 1907, this species is known from the Nearctic region with confirmed records from North Carolina, USA. Like other members of the genus Merogyrus, it is classified within the tribe Aphodiini, a group primarily associated with dung-feeding habits. The species epithet 'rotundiceps' refers to its rounded head structure.
Mesembrina latreillii
Mesembrina latreillii is a large, conspicuous muscid fly historically considered to have a broader distribution but now regarded as restricted to the Nearctic Region following taxonomic revision. The species belongs to a genus typically associated with boreal forests and high-elevation habitats in the Northern Hemisphere.
Mesoleuca
white-ribboned carpets
Mesoleuca is a genus of geometer moths in the family Geometridae, subfamily Larentiinae, first described by Jacob Hübner in 1825. The genus name derives from Greek 'mesos' (middle) and 'leucos' (white), referring to the characteristic white median area on the forewing. Species are commonly known as white-ribboned or beautiful carpets. The genus includes at least three recognized species: M. albicillata (beautiful carpet), M. gratulata (western white-ribboned carpet moth), and M. ruficillata (white-ribboned carpet moth).
Mesomachilis
jumping bristletails
Mesomachilis is a genus of jumping bristletails in the family Machilidae, first described by Silvestri in 1911. The genus contains approximately six described species distributed across North America, including the western United States, Canada, and Mexico. These primitive insects belong to the order Archaeognatha, one of the earliest diverging lineages of living insects.
Messiasia
Messiasia is a genus of mydas flies (family Mydidae) established by Andretta in 1951. The genus contains 16 described species distributed primarily in the Americas, with species known from the western United States, Central America, and South America. These flies are among the largest in Diptera and are characterized by their elongate bodies and wasp-like appearance.
Metaclisis floridana
Metaclisis floridana is a species of parasitoid wasp in the family Platygastridae. The species was originally described by Ashmead in 1887 and was later redescribed as part of a comprehensive revision of Nearctic Metaclisis species. The male of this species was described for the first time in this revision. The genus Metaclisis belongs to the subfamily Platygastrinae and comprises 18 recognized Nearctic species, 16 of which were newly described in the same revision.
Metacyrba floridana
Metacyrba floridana is a species of jumping spider in the family Salticidae. The species was described by Gertsch in 1934. It is native to the southeastern and south-central United States. As a member of the Salticidae, it possesses the characteristic anterior median eyes that provide acute vision used for hunting and navigation.