Hobo Spider, Aggressive House Spider
Tegenaria agrestis
Agelenidae (Funnel-web weavers), Order Araneae
Physical Description
Robust body with a distinctly patterned brown cephalothorax and elongated, cylindrical spinnerets visible at the rear of the abdomen. The silhouette shows long, spiny legs typical of funnel weavers.
Size Estimate
Body length approximately 10 to 14 millimeters, with a leg span reaching up to 40 millimeters.
Coloration & Markings
Brownish coloration with a distinctive herringbone or chevron pattern running down the dorsal side of the abdomen. The cephalothorax typically features indistinct yellowish-brown longitudinal stripes.
Web Type
Constructs a characteristic dense, flat sheet web that funnels into a retreat tube where the spider waits for prey, typically built close to the ground in dark, protected areas.
Eye Arrangement
Eight small, similar-sized eyes arranged in two slightly curved, nearly parallel horizontal rows.
Leg Characteristics
Long, robust legs covered in visible hairs and spines without distinct dark banding, allowing for rapid movement across surfaces.
Venom & Safety Information
Venom Information
Contains necrotic venom components, though historical claims of severe necrotic lesions from bites have been largely challenged or downgraded by modern toxicological studies.
Medical Significance
Historically considered medically significant due to suspected necrotic bites, but current consensus indicates bites generally cause mild to moderate localized pain, redness, and temporary swelling similar to other common spiders.
Safety Recommendations
Wear gloves when clearing dark woodpiles or debris, seal cracks around home foundations, and gently relocate indoor spiders using a glass and stiff paper.
Habitat & Behavior
Habitat & Range
Native to Europe and introduced to the Pacific Northwest of North America. Found in moist, dark environments such as woodpiles, foundations, and beneath rocks or debris.
Behavior & Temperament
Defensive rather than aggressive, typically biting only when trapped against the skin or heavily provoked. Fast-moving ground hunters.
Diet & Prey
Primarily feeds on crawling insects such as beetles, flies, and other spiders caught in or near its funnel web.
Seasonal Activity
Most active during late summer and autumn, particularly during the mating season when mature males wander in search of females.
Description
The Hobo Spider is a classic funnel-weaver known for its rapid speed and characteristic sheet webs. While often feared due to past misconceptions regarding necrotic bites, it is generally a reclusive dweller that prefers dark, undisturbed crevices outdoors and occasionally in human structures.
Key Features
Absence of strong dark banding on the legs, presence of distinct chevron patterns on the abdomen, and prominent funnel-shaped webs near the ground.
Similar Species
Giant House Spider (Eratigena atrica) and other funnel-web species; distinguished primarily by subtle structural genital differences and finer pattern variations.
Life Cycle
Females produce disc-shaped egg sacs in the autumn, guarding them through the winter. Spiderlings emerge in spring, undergoing several molts to reach maturity by late summer.
Ecological Importance
Acts as an effective natural predator for controlling local insect populations in gardens and around structural foundations.
Conservation Status
Not threatened; secure and locally abundant across its native and introduced ranges.
Interesting Facts
Despite its specific epithet 'agrestis' (meaning 'rural' or 'of the fields'), this species frequently adapts to human-made environments and foundations.
Photography Tips
Use macro lenses with adequate side-lighting to highlight the abdominal chevron patterns and cephalothorax stripes while maintaining a safe, non-provocative distance.
Identified: 2026-09-18T23:24:00.267488