American Grass Spider
Agelenopsis pennsylvanica
Agelenidae (Funnel Web Weavers), Order Araneae
Physical Description
Elongated body with a tapering abdomen and prominent, elongated spinnerets extending from the rear. The cephalothorax is oblong with distinct longitudinal dark stripes. Overall texture is moderately hairy with visible spines on the legs.
Size Estimate
Body length typically ranges from 10 to 18 mm, with a leg span reaching up to 40 mm or more. This specimen appears to be an adult or sub-adult.
Coloration & Markings
Tan to brown base coloration with prominent dark brown or black longitudinal bands running down the length of the cephalothorax. The abdomen features a central lighter band bordered by darker mottled patterns and chevron markings toward the rear.
Web Type
Builds a sheet-like web close to the ground in grass, low bushes, or building corners, featuring a distinctive funnel-shaped retreat at one side where the spider waits for prey.
Eye Arrangement
Eight small eyes arranged in two distinct, slightly curved rows of four, typical of the Agelenidae family, designed for wide-angle motion detection.
Leg Characteristics
Long, tapering legs with distinct dark banding and prominent spines. The legs are held flat against the surface in a sprawling posture, adapted for rapid sprinting rather than climbing smooth vertical walls.
Venom & Safety Information
Venom Information
Contains mild venom used primarily to immobilize insect prey. It is not considered dangerous or medically significant to humans.
Medical Significance
Harmless to humans. A bite may cause minor, temporary local discomfort, redness, or swelling akin to a mild bee sting, but medical attention is rarely necessary.
Safety Recommendations
No special safety measures needed. If found inside, simply use a container and a piece of card to gently relocate the spider outdoors.
Habitat & Behavior
Habitat & Range
Common throughout North America, frequently found in lawns, meadows, fields, gardens, and around human structures such as foundations, window wells, and porches.
Behavior & Temperament
Extremely fast and skittish. When disturbed, they typically retreat rapidly into their funnel web. They are non-aggressive toward humans and will only bite if trapped directly against the skin.
Diet & Prey
Carnivorous predator feeding on a wide variety of ground-dwelling insects including crickets, grasshoppers, flies, beetles, and ants.
Seasonal Activity
Most active during late spring through autumn, with peak visibility in late summer and early fall when adults reach full size and males wander in search of mates.
Description
The American Grass Spider is a familiar and beneficial garden inhabitant known for constructing intricate sheet webs that end in a cozy funnel. With its striking striped pattern and incredible speed, it is a quintessential daytime hunter of the lawn and garden ecosystem.
Key Features
Distinctive longitudinal stripes on the cephalothorax, elongated spinnerets at the rear of the abdomen, and a sheet-like funnel web.
Similar Species
Wolf spiders (Lycosidae) and nursery web spiders (Pisauridae), which can be distinguished by the lack of prominent elongated spinnerets and different eye arrangements.
Life Cycle
Females produce disc-shaped silk egg sacs in sheltered spots during autumn. Spiderlings emerge in spring, undergoing multiple molts to reach maturity by late summer.
Ecological Importance
Acts as an effective natural pest control agent by regulating insect populations in gardens, lawns, and agricultural fields.
Conservation Status
Not threatened or endangered; widespread, abundant, and highly adaptable to human-altered environments.
Interesting Facts
Grass spiders are among the fastest terrestrial invertebrates for their size, capable of explosive acceleration when chasing prey or escaping predators.
Photography Tips
Use a macro lens with a fast shutter speed to capture details of the striped cephalothorax and spinnerets from above while avoiding sudden movements that trigger their escape.
Identified: 2026-09-22T19:34:25.607515