Hobo Spider, Aggressive House Spider
Eratigena agrestis
Agelenidae (Funnel Web Weavers), Order Araneae
Physical Description
Medium-sized spider with a robust body consisting of a distinct cephalothorax and elongated abdomen. Typically features a brownish coloration with a patterned dorsal side of the abdomen. The texture is slightly velvety with fine hairs covering the body and legs.
Size Estimate
Body length ranges from 11 to 18 mm for females and 9 to 15 mm for males, with a leg span reaching up to 40 to 45 mm. The specimen appears to be an adult.
Coloration & Markings
Dull brown base color with distinctive yellowish-brown markings forming a chevron or herringbone pattern along the midline of the dorsal abdomen. The cephalothorax features diffuse lighter and darker brown longitudinal stripes.
Web Type
Constructs a characteristic funnel-shaped sheet web of non-sticky silk, usually built near ground level in dark, protected crevices, with a retreat tube where the spider waits for prey.
Eye Arrangement
Eight small, dark eyes of roughly equal size arranged in two slightly curved, nearly parallel horizontal rows across the front of the cephalothorax.
Leg Characteristics
Long, robust legs covered in fine hairs and prominent spines. Unlike some spiders, the legs lack conspicuous dark banding, maintaining a uniform light-to-medium brown coloration.
Venom & Safety Information
Venom Information
Contains a necrotic venom, though historical claims of severe dermonecrotic lesions resulting from its bite have been debated and often misattributed in scientific literature.
Medical Significance
Historically considered medically significant due to fears of necrotic wounds, modern research suggests bites typically result in mild, localized pain, redness, and occasionally localized tissue irritation similar to a bee sting.
Safety Recommendations
Reduce clutter around foundations, seal cracks and crevices in the home, wear gloves when handling stored items or firewood, and safely relocate spiders using a cup and cardboard if found indoors.
Habitat & Behavior
Habitat & Range
Originally native to Europe and Central Asia, introduced to the Pacific Northwest of North America. Prefers undisturbed, dark areas such as woodpiles, rock walls, and the ground-level corners of buildings and basements.
Behavior & Temperament
Crepuscular to nocturnal hunter. It is generally not aggressive toward humans and will usually attempt to flee when disturbed, though it may bite if trapped or squeezed against skin.
Diet & Prey
Primarily preys on crawling insects such as beetles, flies, silverfish, and roaches, which become trapped on the non-sticky sheet web.
Seasonal Activity
Peak activity occurs in late summer and autumn when mature males wander extensively in search of females, making them most commonly encountered indoors during this period.
Description
The hobo spider is a fascinating web-weaving arachnid known for its characteristic funnel web and preference for dark, low-level retreats. While it gained a notorious reputation due to unverified medical concerns, it plays a vital ecological role as a predator of crawling household and garden pests.
Key Features
Absence of dark banding on the legs, distinctive chevron markings on the abdomen, and construction of a low-profile funnel web near the ground.
Similar Species
Giant House Spider (Eratigena atrica) and Domestic House Spider (Tegenaria domestica). Distinguished primarily through microscopic examination of genital structures.
Life Cycle
Females produce disc-shaped egg sacs in the autumn, attaching them to protected surfaces under objects or in crevices. Spiderlings emerge in spring, undergoing multiple molts to reach maturity by late summer.
Ecological Importance
Serves as an effective natural predator of pest insect populations in both agricultural and domestic perimeters, helping regulate local arthropod numbers.
Conservation Status
Not evaluated by the IUCN, but populations are stable and widespread across its introduced and native ranges.
Interesting Facts
Despite its scientific species name 'agrestis' meaning 'field or rural', it frequently adopts human habitations and foundations as ideal microhabitats.
Photography Tips
Use a macro lens with a ring flash or diffused external lighting to capture the fine details of the abdominal chevron pattern and eye arrangement from a safe distance without disturbing the spider.
Identified: 2026-08-21T21:27:01.574822