Hobo Spider, Aggressive House Spider
Eratigena agrestis
Agelenidae (Funnel-Weavers), Order Araneae. Key family characteristics include three pairs of spinnerets with the posterior pair being noticeably elongated, and building characteristic sheet-like funnel webs.
Physical Description
The body is divided into a brown cephalothorax and a patterned abdomen. The cephalothorax often displays indistinct dark longitudinal stripes, while the abdomen features a distinctive chevron or herringbone pattern with pale markings along the midline. The overall appearance is moderately hairy.
Size Estimate
Body length typically ranges from 11 to 18 millimeters for females and 9 to 15 millimeters for males. The leg span can reach up to 40 millimeters. The specimen shown appears to be a medium-sized adult or a late-stage juvenile.
Coloration & Markings
Ground color is generally dull brown to yellowish-brown. The carapace lacks striking patterns except for diffuse dark bands radiating outward. The dorsal abdomen features a prominent series of dark chevron patterns pointing forward.
Web Type
Builds a dense, non-sticky sheet web that terminates in a funnel-shaped retreat where the spider waits for prey. These webs are typically constructed near ground level in dark, protected corners.
Eye Arrangement
Equipped with eight eyes of roughly equal size arranged in two nearly straight horizontal rows across the front of the cephalothorax.
Leg Characteristics
Long and robust legs covered in fine hairs and distinct spines. Unlike some other spiders, the legs generally lack prominent dark banding, presenting a uniform brownish color.
Venom & Safety Information
Venom Information
Contains a necrotic venom similar in action to Loxosceles species, though historically debated regarding its true potency in humans. Envenomation can cause localized pain, redness, and in some cases tissue necrosis.
Medical Significance
Historically considered medically significant due to fears of necrotic lesions, modern arachnology suggests true necrotic reactions from hobo spider bites are rare or often misdiagnosed. Bites result in localized pain and hard red swelling, requiring first aid and monitoring.
Safety Recommendations
Reduce clutter around foundations, wear gloves when moving firewood or stored items, and use a glass and a piece of card to safely capture and relocate indoor specimens outdoors.
Habitat & Behavior
Habitat & Range
Native to Europe and introduced to the Pacific Northwest of North America and parts of Central Asia. Found in dark, moist, low-to-the-ground areas such as woodpiles, foundations, tall grass, and occasionally inside homes in undisturbed corners.
Behavior & Temperament
Crepuscular to nocturnal hunters. They are notoriously defensive rather than aggressive, biting primarily when trapped against human skin or accidentally compressed.
Diet & Prey
Generalist predators feeding primarily on crawling insects such as beetles, flies, and other spiders. Prey is subdued in the funnel web and bitten.
Seasonal Activity
Most active during late summer and autumn, particularly around August and September when mature males wander extensively in search of females.
Description
The hobo spider is a quintessential funnel-weaver, known for constructing dense sheet webs in secluded locations. With its mottled brown coloration and chevron-marked abdomen, it blends seamlessly into bark and dry vegetation. While its reputation has often preceded it as a dangerous visitor, it is fundamentally a shy, ground-dwelling creature performing valuable pest control.
Key Features
Distinctive herringbone or chevron pattern on the dorsal abdomen, lack of prominent dark banding on the legs, and the construction of a funnel web without sticky capture threads.
Similar Species
Often confused with the Giant House Spider (Eratigena atrica) and Domestic House Spider (Tegenaria domestica). Distinguishing often requires microscopic examination of the genitalia, though size and subtle carapace patterns can provide clues.
Life Cycle
Females produce disc-shaped egg sacs in the autumn, attaching them to protected surfaces near the web. Spiderlings overwinter and mature by the following summer. Adults typically live for one to two years.
Ecological Importance
Acts as an effective natural controller of crawling insect populations in both natural habitats and around human habitations.
Conservation Status
Not evaluated by the IUCN, but populations are secure and widespread, often expanding their introduced range.
Interesting Facts
Despite its specific epithet 'agrestis' meaning 'of the fields', this spider has successfully adapted to human-altered environments and structures, frequently finding its way into basements and ground-level rooms.
Photography Tips
Photograph from above to capture the chevron abdominal pattern clearly. Use soft, diffused lighting to avoid harsh shadows and maintain a safe distance using a macro lens.
Identified: 2026-08-13T09:56:29.144039