Hobo Spider, Aggressive House Spider
Eratigena agrestis
Agelenidae (Funnel Web Weavers), Order Araneae. Key family characteristics include long spinnerets and a habit of building sheet webs with a funnel-shaped retreat.
Physical Description
Elongated body with a brownish, patterned appearance. The cephalothorax is relatively smooth with indistinct markings, and the abdomen features a distinct herringbone or chevron pattern along the dorsal surface. It is moderately hairy.
Size Estimate
Body length is approximately 11 to 18 millimeters for females and 8 to 14 millimeters for males, with a leg span reaching up to 40 to 45 millimeters. This appears to be an adult specimen.
Coloration & Markings
Muted brown, tan, and yellowish-brown base coloration. The key marking is a series of dark chevron or herringbone patterns running down the center of the dorsal abdomen, pointing forward.
Web Type
Funnel web or sheet web. The spider constructs a dense, non-sticky horizontal sheet of silk that ends in a funnel-shaped retreat where the spider hides, waiting for prey to walk across the sheet.
Eye Arrangement
Eight eyes of roughly uniform size, arranged in two approximately horizontal, slightly curved rows of four.
Leg Characteristics
Long, moderately robust legs with visible spination and fine hairs. The legs generally lack distinct dark or light banding, maintaining a uniform brownish color.
Venom & Safety Information
Venom Information
Contains cytotoxins. Envenomation can cause localized tissue necrosis, severe headaches, and localized pain, though the medical significance and historical reputation for aggressive biting are subjects of ongoing scientific debate.
Medical Significance
Historically considered medically significant due to necrotic bite symptoms, though recent toxicology and epidemiological studies suggest their bite severity may have been overstated. Seek medical attention if a bite shows signs of spreading redness, blistering, or tissue breakdown.
Safety Recommendations
Avoid handling with bare hands, wear gloves when cleaning dark basements or moving woodpiles, and use a glass and a piece of cardboard to safely capture and relocate indoor specimens outside.
Habitat & Behavior
Habitat & Range
Originally native to Europe and Central Asia, introduced to the Pacific Northwest of North America. Found in moist, dark areas, tall grass, woodpiles, and frequently indoors in basements or under furniture.
Behavior & Temperament
Typically reclusive and reluctant to bite unless trapped or firmly pressed against human skin. They are primarily ground-dwellers and fast runners, active mostly at night.
Diet & Prey
Generalist predators feeding on crawling insects such as beetles, flies, roaches, and other spiders that stumble onto their sheet webs.
Seasonal Activity
Most commonly seen in late summer and autumn when mature males leave their webs to search for females. They overwinter as immatures or sheltered adults.
Description
The hobo spider is a robust funnel-weaver well-known for its distinctive herringbone abdominal pattern and rapid running speed. While often viewed with caution by homeowners due to its historical reputation, it is primarily a shy dweller of dark corners and gardens, playing an important role in controlling insect populations.
Key Features
Distinct herringbone pattern on the abdomen, lack of noticeable dark banding on the legs, uniform eye arrangement, and construction of a characteristic funnel-shaped retreat web.
Similar Species
Giant House Spider (Eratigena atrica) and Barn Funnel Weaver (Tegenaria domestica). These can be distinguished primarily through microscopic examination of genital structures or subtle differences in leg banding and size.
Life Cycle
Females produce disc-shaped egg sacs in the autumn, attaching them to sheltered surfaces. Spiderlings hatch in spring, undergo multiple molts, and reach maturity by late summer to early autumn, living for about one to two years.
Ecological Importance
Serves as an effective natural predator of household and garden pests, helping to regulate insect populations while forming part of the diet for larger birds and small mammals.
Conservation Status
Not evaluated by the IUCN, but populations are secure and expanding in their introduced ranges.
Interesting Facts
Despite its common name 'agrestis' meaning 'of the fields' in Latin, it is frequently found in close proximity to human habitations, and males wander extensively in autumn looking for mates.
Photography Tips
Photograph from a safe distance using macro lenses. Capture top-down views to clearly show the abdominal herringbone pattern and side views to document leg spination and cephalothorax shape.
Identified: 2026-08-13T09:10:10.097598