Hobo Spider, Aggressive House Spider
Tegenaria agrestis
Agelenidae (Funnel-weaver spiders), Order Araneae. Key family characteristics include three pairs of spinnerets with the posterior pair significantly elongated, and distinctive funnel-shaped webs.
Physical Description
The spider has a relatively elongated body, featuring a brownish cephalothorax with distinct darker longitudinal stripes and a grayish-brown abdomen with a chevron or herringbone pattern down the center.
Size Estimate
Body length ranges from 11 to 18 mm for females and 9 to 15 mm for males, with a total leg span reaching up to 40 mm. This appears to be an adult specimen.
Coloration & Markings
Ground color is typically brown to yellowish-brown. The cephalothorax lacks prominent markings other than subtle dark radial stripes. The most diagnostic feature is the series of dark, distinct chevron patterns on the dorsal abdomen pointing forward.
Web Type
Builds a characteristic funnel web consisting of a flat, sheet-like web of non-sticky silk that leads into a tubular retreat where the spider waits for prey.
Eye Arrangement
Eight small eyes of roughly equal size, arranged in two approximately horizontal, slightly curved rows.
Leg Characteristics
Long, robust legs covered in fine hairs and visible spines. The legs are uniformly brown and lack the distinct dark bands or rings found in some similar house-dwelling species.
Venom & Safety Information
Venom Information
Contains a necrotic venom component, though its potency and significance in human envenomation have been subject to scientific debate and exaggeration.
Medical Significance
Historically considered dangerous due to suspected necrotic lesions from bites, but modern medical consensus suggests bites typically result in mild to moderate localized pain, redness, and occasionally localized tissue irritation.
Safety Recommendations
Reduce clutter in basements and garages, seal cracks around doors and windows, and wear gloves when moving stored items. Relocate indoor spiders outdoors using a cup and a piece of paper.
Habitat & Behavior
Habitat & Range
Originally native to Europe and Central Asia, introduced to the Pacific Northwest of North America. Found in fields, under rocks, and frequently indoors in dark, low corners, basements, and behind furniture.
Behavior & Temperament
Crepuscular to nocturnal hunter. Reluctant to bite unless trapped or directly threatened against the skin. They possess poor eyesight and rely heavily on vibrations transmitted through their web.
Diet & Prey
Generalist predator feeding on crawling insects including roaches, beetles, earwigs, and flies trapped on or near the sheet web.
Seasonal Activity
Most active during late summer and autumn when mature males wander extensively in search of females.
Description
The Hobo Spider is a sturdy, agile runner often encountered near baseboards and corners in homes within its introduced range. Known for constructing characteristic funnel webs, it plays an effective role in controlling household insect populations despite its intimidating appearance.
Key Features
Absence of dark bands on the legs, presence of distinct chevron (herringbone) patterns on the abdomen, and the construction of a funnel-shaped sheet web.
Similar Species
Giant House Spider (Eratigena duellica) and Barn Funnel Weaver (Tegenaria domestica), which are generally larger or have banded legs.
Life Cycle
Females produce disc-shaped egg sacs in the autumn, depositing them in the web retreat. Spiderlings emerge in spring, undergoing multiple molts to reach maturity by late summer.
Ecological Importance
Acts as an effective natural predator for controlling populations of agricultural and household insect pests.
Conservation Status
Not evaluated by the IUCN; abundant and secure throughout its native and introduced ranges.
Interesting Facts
Despite its specific epithet 'agrestis' (meaning rural or of the fields) and the common name 'aggressive house spider', it is actually quite defensive rather than aggressive and prefers to flee when disturbed.
Photography Tips
Photograph from a safe distance using macro lenses in natural or diffused lighting, focusing on the dorsal abdominal pattern and the leg joints to confirm species-level identification.
Identified: 2026-10-01T05:44:39.104032