Grass Spider, American Grass Spider, Funnel-Weaver
Agelenopsis species (likely Agelenopsis pennsylvanica or Agelenopsis potteri)
Agelenidae (Funnel-Weavers / Funnel-Web Spiders), Order Araneae
Physical Description
Elongated body with a distinct, prominent pair of long two-segmented posterior spinnerets extending beyond the tip of the abdomen. The carapace is oval with prominent longitudinal stripes, and the abdomen features a dark central cardiac mark bordered by lighter chevron patterns.
Size Estimate
Body length is approximately 10 to 18 mm (excluding legs), with a leg span of roughly 25 to 40 mm. This specimen appears to be an adult or sub-adult based on body proportions.
Coloration & Markings
Grayish-brown to tan ground color. Carapace features two dark brown longitudinal stripes running parallel along the sides of a lighter median band. The abdomen displays a central dark lanceolate stripe flanked by lighter yellowish-tan lines and subtle chevron markings.
Web Type
Funnel web weaver. Constructs a non-sticky, flat, sheet-like web that leads into a protected, tube-shaped funnel retreat built in crevices, grass, foliage, or structure edges.
Eye Arrangement
Eight eyes arranged in two strongly procurved rows forming a distinctive 'procurved' pattern (almost forming an arch) on a narrow ocular area, facilitating rapid forward and lateral movement detection.
Leg Characteristics
Long, slender, hairy legs equipped with prominent dark spines. Legs are light brown to tan with faint darker banding or annulations.
Venom & Safety Information
Venom Information
Contains agatoxins which affect insect nervous systems. The venom is harmless to humans and domestic pets, causing no systemic toxicity.
Medical Significance
Harmless to humans (not medically significant). A rare bite might cause mild localized pain, slight swelling, or minor redness comparable to a bee sting.
Safety Recommendations
No control measures necessary. If found indoors, safely relocate outdoors using a cup and card. Wear gloves when moving old outdoor woodpiles or debris where webs reside.
Habitat & Behavior
Habitat & Range
Common throughout North America (United States and southern Canada). Found in grassy fields, lawns, shrubs, woodpiles, barn structures, porches, and around house foundations.
Behavior & Temperament
Extremely fast, agile runners. They are shy, non-aggressive, and retreat rapidly into their funnel web or nearby crevices when threatened. They bite only when crushed or directly handled.
Diet & Prey
Generalist predators feeding on various flying and crawling insects including crickets, moths, flies, beetles, leafhoppers, and ants that walk across their sheet web.
Seasonal Activity
Peak visibility occurs in late summer and autumn when adults reach full size and construct prominent webs for mating season.
Description
Agelenopsis, commonly known as the Grass Spider, is one of the most common funnel-web builders in North America. Known for its remarkable speed, this spider relies on a non-sticky sheet web to detect prey vibrations before darting out of its funnel retreat to subdue insects. Easily identified by two dark longitudinal bands across its carapace and long tail-like spinnerets, it plays a vital role as an beneficial pest control predator around homes and gardens.
Key Features
Distinct long two-segmented posterior spinnerets projecting from the abdominal tip; two broad dark brown longitudinal stripes on carapace; rapid locomotion; sheet-like funnel web.
Similar Species
Wolf Spiders (Lycosidae) - lack long prominent spinnerets and have larger anterior eyes; Rabid Wolf Spider (Rabidosa rabida) - similar carapace stripes but lacks funnel spinnerets; Nursery Web Spiders (Pisauridae) - different eye pattern and lack distinct long spinnerets.
Life Cycle
Annual life cycle in temperate regions. Females construct a flattened, white silk egg sac in autumn tucked into protected crevices before dying before winter. Spiderlings emerge in spring and disperse.
Ecological Importance
Highly beneficial natural controller of insect populations around human habitats, gardens, and agricultural ecosystems.
Conservation Status
Not evaluated (Least Concern); extremely common and abundant across its native range.
Interesting Facts
Grass spider silk is not sticky; instead, spiders rely purely on incredible speed—running up to several miles per hour relative to scale—to catch insects that land on their web platform.
Photography Tips
Focus sharply on the carapace to capture the stripe pattern and look for a direct rear shot showing the characteristic long spinnerets. Soft directional lighting works best to reduce sheen on silk and carapace.
Identified: 2026-07-27T21:38:29.951663