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 robust and elongated with a distinctly patterned dorsal abdomen and a brownish cephalothorax featuring darker longitudinal stripes. The cephalothorax is relatively hairless compared to other spiders. Sexual dimorphism is present, with females having a slightly larger, rounder abdomen and males possessing visibly swollen, boxing-glove-like palps at the front of the face.
Size Estimate
Body length ranges from 11 to 18 millimeters for females and 9 to 15 millimeters for males, with a substantial leg span reaching up to 40 to 45 millimeters. This specimen appears to be an adult.
Coloration & Markings
The base coloration ranges from light brown to a rich yellowish-brown. The abdomen features a distinct pattern of yellowish chevron or herringbone markings pointing forward, contrasted against a darker background. The sternum typically has a pale yellowish stripe down the middle with dark markings on either side.
Web Type
Builds a characteristic dense, non-sticky sheet web that funnels back into a tubular retreat where the spider waits in concealment. These webs are typically constructed near the ground in dark, undisturbed areas such as under woodpiles, in crawlspaces, or corners of rooms.
Eye Arrangement
Eight small, dark eyes arranged in two roughly parallel, slightly curved rows of four. All eyes are similar in size, set on a dark base, which is a diagnostic feature for the funnel-weaver family.
Leg Characteristics
Long, robust, and tapering legs covered in fine, inconspicuous hairs rather than prominent spines or distinct banding. The legs are held in a sprawling, flattened posture typical of funnel-weavers and are built for rapid, darting movement.
Venom & Safety Information
Venom Information
Possesses a cytotoxic venom. Historically reputed to cause severe necrotic lesions similar to a brown recluse bite, though modern arachnological studies suggest human envenomation symptoms are typically mild, consisting mostly of localized pain and redness.
Medical Significance
Generally considered of low to moderate medical significance. While bites can be painful and occasionally result in temporary localized tissue damage, severe necrotic reactions are rare and often attributed to secondary infections or misdiagnoses.
Safety Recommendations
Wear gloves when moving firewood or cleaning out dark, undisturbed storage areas. If a hobo spider is found inside, safely relocate it outdoors using a cup and a piece of card. Seek medical attention if a bite shows signs of spreading infection or severe pain.
Habitat & Behavior
Habitat & Range
Native to Europe and introduced to the Pacific Northwest of North America. Prefers dry, undisturbed habitats at ground level, commonly found outdoors in tall grass, under rocks, and in woodpiles, as well as indoors in basements, crawlspaces, and garages.
Behavior & Temperament
A nocturnal, highly agile web-trapper that relies on rapid speed to capture prey. Despite its common name 'aggressive house spider', it is generally defensive rather than aggressive, biting usually only when trapped, squeezed, or accidentally sat upon.
Diet & Prey
Feeds primarily on crawling insects such as beetles, flies, roaches, and occasionally other spiders. Prey is detected through vibrations on the sheet web, rushed down upon, and subdued with venom before being dragged into the funnel retreat.
Seasonal Activity
Peak activity occurs during late summer and autumn (August to October), which is when mature males actively wander in search of females, leading to increased encounters with humans indoors.
Description
The hobo spider is a quintessential funnel-weaver, known for its rapid movements and intricate sheet webs. With its brownish coloration and signature chevron pattern on the abdomen, it blends seamlessly into wooden structures and brush. While sometimes feared due to historical misconceptions regarding its venom, it plays an important role in controlling insect populations around human habitations.
Key Features
Distinctive herringbone or chevron pattern on the dorsal abdomen, lack of distinct banding on the legs, a pale stripe on the sternum, and construction of a low-lying funnel-shaped sheet web.
Similar Species
Giant House Spider (Eratigena atrica), which is generally larger and darker; Wolf Spiders (Lycosidae), which do not build webs and have a dramatically different eye arrangement.
Life Cycle
Females construct silken egg sacs in late summer or autumn, depositing 50 to 100 eggs which overwinter and hatch in spring. Spiderlings disperse via ground movement. Adults typically live for one to two years, with males often dying after mating in the autumn.
Ecological Importance
Acts as an efficient apex predator of ground-dwelling arthropods, helping to regulate insect populations in both natural and domestic environments.
Conservation Status
Not evaluated by the IUCN. Populations are stable and widespread, and the species is considered invasive in certain regions of North America.
Interesting Facts
The name 'agrestis' translates to 'of the fields' in Latin. Unlike many house spiders, hobo spiders are poor climbers on smooth vertical surfaces like glass or porcelain due to the lack of specialized claw tufts.
Photography Tips
Use macro lenses with a high depth of field to capture the dorsal chevron patterns and the sternum. Photograph from a safe distance using natural side-lighting or diffused flash to highlight texture while avoiding startling the spider.
Identified: 2026-09-26T20:11:58.961091