Pennsylvania Grass Spider, American Grass Spider, Funnel Weaver
Agelenopsis pennsylvanica
Agelenidae (Funnel-Weavers), Order Araneae. Key family characteristics include long spinnerets and the construction of sheet-like funnel webs.
Physical Description
Elongated body with a tapering abdomen, prominent spinnerets visible at the rear, and long, spiny legs. The cephalothorax features distinct longitudinal dark bands.
Size Estimate
Body length typically ranges from 10 to 18 mm, with a leg span reaching up to 40-50 mm. This specimen appears to be an adult.
Coloration & Markings
Brownish-grey base coloration with prominent dark brown or black longitudinal stripes running along the dorsal side of the cephalothorax and sides of the abdomen.
Web Type
Builds a horizontal sheet web ending in a tubular retreat or funnel, typically constructed in grass, shrubs, or structural crevices like window frames.
Eye Arrangement
Eight eyes arranged in two rows, relatively equal in size, spread across the front of the carapace in a characteristic agelenid pattern.
Leg Characteristics
Long, robust, and heavily spined legs with distinct dark banding, adapted for rapid running rather than climbing smooth vertical surfaces.
Venom & Safety Information
Venom Information
Neurotoxic venom used to immobilize small insect prey. It is mild and generally ineffective against human skin.
Medical Significance
Harmless to humans. Bites are rare, typically no more painful than a mild bee sting, and lack medical significance.
Safety Recommendations
No special precautions needed. If found indoors near windows, they can be gently relocated outside using a cup and a piece of paper.
Habitat & Behavior
Habitat & Range
Found across North America, particularly the eastern and midwestern United States. Prefers lawns, fields, gardens, and exterior structural gaps such as window sills.
Behavior & Temperament
Extremely fast and skittish. When disturbed, they rapidly retreat into their funnel. They are non-aggressive toward humans and will only bite if firmly trapped or squeezed.
Diet & Prey
Generalist predators feeding on grasshoppers, flies, beetles, and other small insects that land on their sheet web.
Seasonal Activity
Most active during late summer and autumn when mature adults wander in search of mates before dying off with the first hard frosts.
Description
The Pennsylvania Grass Spider is a swift and agile hunter known for its intricate sheet webs that end in a cozy funnel retreat. Often spotted around homes and gardens, this furry, striped arachnid plays a vital role in keeping local insect populations in check while posing zero threat to humans.
Key Features
Distinct longitudinal dark stripes on the cephalothorax, elongated spinnerets, and rapid running behavior combined with a funnel-shaped web.
Similar Species
Wolf spiders (Lycosidae) which do not build webs, and other Agelenopsis species which require microscopic examination of genitalia for definitive separation.
Life Cycle
Females construct silken egg sacs in sheltered spots in autumn, where eggs overwinter before hatching into spiderlings in spring.
Ecological Importance
Serves as an important predator of garden pests and acts as a food source for birds, small mammals, and larger predatory insects.
Conservation Status
Secure and widespread, with stable populations across its native North American range.
Interesting Facts
Grass spiders are among the fastest terrestrial invertebrates, capable of explosive acceleration when chasing prey across their sheet webs.
Photography Tips
Use a fast shutter speed to capture their quick movements. Shoot from a low angle parallel to the web or surface for dramatic effect.
User Notes
found between two windows in Philadelphia
Identified: 2026-09-29T12:06:18.069013