Hobo Spider or Grass Spider
Tegenaria agrestis (or Agelenopsis species)
Agelenidae (Funnel Weavers), Order Araneae. Key family characteristics include long spinnerets and a typical funnel-shaped web.
Physical Description
Elongated body structure featuring a distinct carapace with longitudinal stripes and visible spinnerets at the rear. The specimen shown has suffered significant damage, having lost its abdomen and one leg during recovery from a pool.
Size Estimate
Medium-sized spider. Body length typically ranges from 10 to 18 millimeters with a leg span up to 40 millimeters. The visible portion represents an adult or sub-adult specimen.
Coloration & Markings
Brownish base coloration featuring darker brown or grey chevron patterns along the dorsal surface, characteristic of funnel web weavers. The cephalothorax shows faint longitudinal striping.
Web Type
Constructs a sheet web that funnels back into a tubular retreat where the spider waits for prey. These are typically built low to the ground in grass, under rocks, or in dark corners.
Eye Arrangement
Eight eyes arranged in two horizontal rows of four, all relatively uniform in size, typical of the Agelenidae family.
Leg Characteristics
Long, robust legs covered in fine hairs and prominent spines, lacking striking color banding but adapted for rapid running across their sheet webs.
Venom & Safety Information
Venom Information
Contains neurotoxic and cytolytic components meant for subduing insect prey. While historically feared regarding necrotic bites, modern arachnological consensus considers their venom of relatively low medical significance to humans.
Medical Significance
Harmless to mildly significant. Bites are rare and usually only occur when trapped against human skin. Symptoms typically include minor localized pain and redness, akin to a bee sting.
Safety Recommendations
Wear gloves when clearing debris or moving objects in the yard where these spiders might hide. If found indoors, relocate safely using a cup and a piece of cardboard.
Habitat & Behavior
Habitat & Range
Found throughout temperate regions, specifically adapted to suburban and rural environments in Utah, often lurking in dark, moist microhabitats like woodpiles, foundations, and occasionally swimming pools where they accidentally fall.
Behavior & Temperament
Active, fast-moving hunter that relies on its web for vibration detection. Generally defensive rather than aggressive, preferring to flee when disturbed unless cornered.
Diet & Prey
Generalist predator feeding on ground-dwelling insects such as beetles, flies, crickets, and other spiders trapped in its web system.
Seasonal Activity
Most active during late summer and autumn when mature males wander actively in search of females, increasing the frequency of human encounters.
Description
A rugged brown spider well-adapted to ground-level life in temperate North America. Often encountered near human habitation due to overlapping habitats, this specimen's unfortunate accidental drowning in a Utah swimming pool highlights their occasional close proximity to homes.
Key Features
Brown coloration with distinct chevron markings on the abdomen, long spinnerets, and rapid movement across funnel-shaped sheet webs.
Similar Species
Wolf spiders (Lycosidae) and giant house spiders (Eratigena atrica). Distinguished primarily by eye arrangement, spinneret length, and specific abdominal patterns.
Life Cycle
Undergoes multiple molts over one to two years. Females construct silken egg sacs in hidden retreats during autumn, where eggs overwinter until spiderlings emerge in spring.
Ecological Importance
Serves as an effective natural pest control agent by reducing populations of crawling insects around gardens, yards, and human structures.
Conservation Status
Not evaluated by the IUCN, but highly abundant, secure, and locally common across its introduced and native ranges.
Interesting Facts
Hobo spiders earned a fearsome reputation due to misunderstood medical reports in the Pacific Northwest, though extensive research has largely debunked claims of severe flesh-eating wounds.
Photography Tips
Photograph from above using natural indirect lighting to capture dorsal stripe patterns clearly. Maintain a safe distance and use macro settings if available.
User Notes
Found at the bottom of the pool in Utah in a suburban neighborhood . Abdomen and one leg lost in recovery
Identified: 2026-08-02T22:19:34.040202