Grass Spider (Agelenopsis spp.) - Identification, Range & Medical Data

Summary

Grass spiders are funnel-weaving agelenids that build sheet webs with a tubular retreat in lawns, ground cover, and along foundations. Frequently confused with wolf spiders and hobo spiders. They are not medically significant.

Quick answers

Is Grass Spider dangerous to humans?: No. Current evidence does not link grass spider bites to serious medical outcomes in healthy adults.
How big is an adult grass spider?: Adult female body length is 10–20 mm; males are 9–18 mm. Leg span reaches 25–45 mm.
Where does Grass Spider live?: Lawns, low shrubbery, ground cover, foundation walls. Sheet webs are conspicuous on dewy mornings. Established U.S. populations occur in 1 states.
What does Grass Spider eat and when is it active?: Insects that land on the sheet web. Diurnal at the funnel mouth; flees into the retreat when disturbed.

Identification

Body 10–20 mm with prominent longitudinal stripes on cephalothorax and abdomen
Two long visible spinnerets projecting from the rear (agelenid-typical)
Builds a horizontal sheet web with a funnel retreat at one side
Brown to gray with cream or tan stripes

Morphometrics

Measurement	Female	Male
Body length	10–20 mm	9–18 mm
Leg span	25–45 mm	-
Lifespan	1–1 years	-

Trait	Value
Web type	Horizontal sheet web with a funnel-shaped retreat at one corner.
Eye arrangement	Eight eyes in two rows of four, roughly equal size.
Eggs per sac	50–200
Egg sacs per year	1–2

Geographic range

Native range: Throughout North America.

U.S. states with established populations: All 48 contiguous U.S. states.

State pages covering Grass Spider

Alabama Alaska Arizona Arkansas California Colorado Connecticut Delaware Florida Georgia Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia Washington West Virginia Wisconsin Wyoming

Habitat & behavior

Habitat: Lawns, low shrubbery, ground cover, foundation walls. Sheet webs are conspicuous on dewy mornings.

Activity: Diurnal at the funnel mouth; flees into the retreat when disturbed.

Diet: Insects that land on the sheet web.

Venom & medical significance

Venom property	Value
Type	Not medically significant
LD₅₀	Not established
Note	-

Bite symptoms & first aid

Symptoms

Bites are very rare; mild local irritation only

Commonly confused with

Wolf spider
Hobo spider
Brown recluse (because of color)

Key facts

Grass spider sheet webs are the conspicuous 'dewy white blankets' visible across lawns on autumn mornings and are not signs of an infestation. [1]

Sources

[1]Funnel Weavers (Agelenopsis) - Missouri Department of Conservation Field Guide. Accessed 2026-06-14.