Diagnostic characters
- Prominent posterior spinnerets projecting well beyond the abdomen, visible from above
- Two dark longitudinal bands on the carapace
- Long legs held so the body sits low over the sheet
- Sheet web with a funnel retreat in grass, shrubs, window wells, or corners
- Very rapid, direct running when flushed
Habitat and seasonality
Lawns and low shrubs, ground-level vegetation, retaining walls, window wells, garages, crawlspaces, and basement corners.
Sheets become conspicuous in late summer and autumn on dewy mornings. Males wander indoors in autumn seeking mates, which drives most household encounters.
Medical significance
Low. The hobo spider was formerly listed as a cause of necrotic lesions; that attribution has been withdrawn after controlled studies failed to reproduce dermonecrosis and epidemiological support collapsed.
Sheet web function
Unlike an orb, the agelenid sheet has no adhesive. It works as a vibration-transmitting platform and a physical obstacle. The spider waits at the mouth of the funnel with its legs in contact with the sheet, and a walking or landing insect produces vibrations that indicate both direction and distance. Strike times are among the fastest recorded for a web-building spider.
The hobo spider reassessment
Eratigena agrestis was introduced to the Pacific Northwest and was widely described through the 1990s and 2000s as a cause of necrotic arachnidism. Subsequent controlled envenomation studies in rabbits could not reproduce necrotic lesions, verified bite case series showed no necrosis, and the CDC removed the species from its list of venomous spiders in 2017. Current guidance treats hobo spider bites as clinically unremarkable.
Grass spiders in the landscape
Agelenopsis sheets in turf and low shrubbery become highly visible on dew-heavy autumn mornings, which regularly prompts reports of a sudden infestation. The webs were present through the season and only became optically obvious. No control is warranted; the genus is a significant consumer of lawn-dwelling insects.
Families most often confused with Agelenidae
| Family | How to separate it |
|---|---|
| Lycosidae | Wolf spiders build no sheet web and have two enlarged forward-facing eyes |
| Amaurobiidae | Hacklemesh weavers produce bluish cribellate silk and are smaller with stouter legs |
| Hahniidae | Dwarf sheet weavers have spinnerets arranged in a single transverse row |
Profiled species in this family
| Species | Scientific name | Medical significance |
|---|---|---|
| Hobo Spider | Eratigena agrestis | low |
| Grass Spider | Agelenopsis spp. | none |
| Giant House Spider | Eratigena atrica | none |
References
- [1]World Spider Catalog, version 26 - Natural History Museum Bern. Accessed 2026-06-14.
- [2]Spiders of North America: An Identification Manual, 2nd ed. - American Arachnological Society. Accessed 2026-06-14.
- [3]Venomous Spiders - CDC / NIOSH. Accessed 2026-06-14.