Ground-dwelling
Guides
Trochosa terricola
ground wolf spider
A medium-sized wolf spider (Lycosidae) widespread across Europe and extending into Asia and North America. Adults range from 7–14 mm, with females larger than males. The species occupies diverse terrestrial habitats including grassland, heathland, and woodland, showing particular affinity for drier conditions. It is primarily nocturnal and has been documented as prey for pompilid spider wasps.
Udeocorini
dirt-colored seed bugs
Udeocorini is a tribe of dirt-colored seed bugs in the family Rhyparochromidae, established by Sweet in 1967. The tribe comprises approximately 17 genera and more than 30 described species. Members are primarily found in association with ground-level habitats where seeds are available. At least one genus within the tribe, Daerlac, exhibits myrmecomorphy (ant mimicry).
Vacusus
Vacusus is a genus of antlike flower beetles in the family Anthicidae, established by Casey in 1895. The genus comprises approximately six described species distributed across the Americas, including North America, the Caribbean, and Central America. Members of this genus exhibit the characteristic ant-mimicking morphology typical of Anthicidae, with elongated bodies and pronotal constrictions that create a superficial resemblance to ants. The genus has accumulated over 950 observations on iNaturalist, indicating moderate documentation of its species in the field.
Varacosa
Varacosa is a genus of wolf spiders (family Lycosidae) endemic to North America. First described in 1942 by Chamberlin & Ivie, the genus currently contains six recognized species. These spiders are ground-dwelling hunters that serve as important prey for spider wasps in the family Pompilidae, including species such as Ageniella conflicta and Priocnemis minorata.
Xantholinini
Xantholinini is a tribe of rove beetles (Coleoptera: Staphylinidae: Staphylininae) comprising approximately 141 genera with a cosmopolitan distribution across all zoogeographical regions. Members are small to medium-sized (2–20 mm), slender, short-winged beetles with elongated bodies and relatively short legs adapted for moving through narrow spaces. The tribe has been the subject of extensive taxonomic revision, particularly in the Eastern Mediterranean, Turkey, China, and the Neotropics, with numerous new species described in recent decades.
Xeropigo
Xeropigo is a genus of sac spiders in the family Corinnidae, first described by O. Pickard-Cambridge in 1882. The genus comprises 17 described species distributed across South America and the Caribbean, with the majority of species occurring in Brazil. Recent taxonomic revisions have significantly expanded the known diversity, with seven new species described from Brazil in 2016. The genus shows notable species richness in northeastern Brazilian states, particularly Piauí, Ceará, and Maranhão.
Xysticus
Ground Crab Spiders
Xysticus is a large genus of approximately 275–300 species of ground crab spiders in the family Thomisidae. These spiders are ambush predators that do not build webs, instead hunting near the ground by seizing prey with their enlarged anterior legs. The genus exhibits strong sexual dimorphism, with females typically reaching 10 mm in body length while males are roughly half that size. Species identification requires microscopic examination of genitalia due to the morphological similarity among members of the genus.
Xysticus
ground crab spiders
Xysticus is a genus of ground-dwelling crab spiders (family Thomisidae) known for ambush hunting on the ground rather than in flowers. These spiders possess elongated first and second pairs of legs with spines that help secure prey. They are among the most frequently observed ballooning spiders, using silk threads to disperse via wind currents. The genus is also a documented prey source for spider wasps in the genus Dipogon.
Xysticus apachecus
Xysticus apachecus is a species of crab spider in the family Thomisidae, first described by Gertsch in 1933. Like other members of the genus Xysticus, it is a ground-dwelling ambush predator characterized by its crab-like leg posture and sideways movement. The species is known from the United States, though specific details about its ecology and behavior remain limited in the published literature.
Xysticus aprilinus
Xysticus aprilinus is a species of ground crab spider in the family Thomisidae, first described by Bryant in 1930. The genus Xysticus comprises ambush-hunting spiders characterized by their laterally flattened bodies and enlarged front legs adapted for seizing prey. As with other members of this genus, X. aprilinus likely employs a sit-and-wait hunting strategy rather than building webs to capture prey. The species epithet 'aprilinus' suggests a possible association with spring activity, though this has not been formally documented.
Xysticus cristatus
common crab spider
Xysticus cristatus, commonly known as the common crab spider, is a small ambush predator in the family Thomisidae. Females reach 6–8 mm body length, while males are smaller at 3–5 mm. The species exhibits cryptic coloration ranging from light cream to dark brown or greyish, with distinct patterning that blends with dried leaf litter. It hunts by waiting motionless with forelegs spread wide, capturing insects that blunder within reach. The species has a broad Palearctic distribution and has been introduced to North America.
Xysticus emertoni
Emerton's Crab Spider
Xysticus emertoni, commonly known as Emerton's crab spider, is a species of ground crab spider in the family Thomisidae. It occurs across a broad transcontinental range spanning North America and Eurasia, including the United States, Canada, Russia, and Central Asia through China. As a member of the genus Xysticus, it exhibits the typical crab spider body plan with laterally extended legs adapted for ambush predation. The species has been documented as prey for spider wasps in the genus Dipogon.
Xysticus gulosus
Xysticus gulosus is a species of crab spider in the family Thomisidae, described by Keyserling in 1880. It belongs to the genus Xysticus, a diverse group of ground-dwelling ambush predators commonly known as ground crab spiders. The species is distributed across North America, with confirmed records from the Canadian provinces of Alberta, Manitoba, and Saskatchewan. Like other members of its genus, it likely employs a sit-and-wait hunting strategy, using its enlarged front legs to capture prey.
Xysticus speciese
Xysticus speciese is a species of crab spider in the family Thomisidae. The genus Xysticus is characterized by ambush hunting behavior and distinctive leg morphology adapted for seizing prey. Members of this genus are typically ground-dwelling and known to overwinter as adults or immatures.
Xysticus triguttatus
Three-banded Crab Spider
Xysticus triguttatus, commonly known as the three-banded crab spider, is a small ambush-hunting spider in the family Thomisidae. The species is widely distributed across North America, with records from the United States and Canada including Alberta, Manitoba, and Saskatchewan. As a member of the genus Xysticus, it exhibits the characteristic crab-like posture and hunting behavior typical of ground crab spiders, lying in wait for prey rather than constructing webs.
Zodariidae
Ant-eating Spiders, Ant Spiders
Zodariidae, commonly known as ant-eating spiders, is a family of small to medium-sized eight-eyed spiders found worldwide in tropical to warm temperate regions. The family comprises approximately 90 genera and 1,249 species, with the highest diversity in Australia. Members are predominantly ground-dwelling, free-living predators that do not construct webs for prey capture. Many species exhibit specialized ant-eating habits and aggressive mimicry, disguising themselves as ants to hunt their primary prey. The family has relatively few species in North America compared to other regions.
Zoropsidae
False Wolf Spiders
Zoropsidae, commonly known as false wolf spiders, is a family of cribellate araneomorph spiders first described by Philipp Bertkau in 1882. The family includes approximately 180 species across 28 genera as of 2026. Members are wandering spiders that bear superficial resemblance to wolf spiders (Lycosidae) but are distinguished by their eye arrangement. The family has undergone taxonomic revision, with Tengellidae and Zorocratidae now included within Zoropsidae. One species, Zoropsis spinimana, has been introduced to the United States.