Grass Spider, Funnel Weaver
Agelenopsis sp.
Agelenidae (Funnel Weavers), Order Araneae. Characterized by long spinnerets and horizontal sheet webs with a retreat.
Physical Description
Elongated, pear-shaped cephalothorax with a teardrop-shaped abdomen. The abdomen often terminates in two distinct, long, tube-like spinnerets. The body has a hairy (setose) texture and is generally robust and agile.
Size Estimate
Body length 10-20mm; total leg span 25-50mm. This specimen appears to be a sub-adult or adult female based on body proportions.
Coloration & Markings
Dorsal side features two prominent dark longitudinal stripes running the length of the cephalothorax. The abdomen displays a central chevron or 'herringbone' pattern in shades of brown, tan, and gray, flanking a lighter median band.
Web Type
Dense, non-sticky horizontal sheet web that narrows into a funnel-shaped retreat in a crevice or corner. The web is designed to detect vibrations rather than entangle prey in glue.
Eye Arrangement
Eight eyes arranged in two rows that appear highly curved (procurved), creating a pattern that looks almost like three rows: 2:4:2. Smaller eyes than wolf spiders.
Leg Characteristics
Long, moderately thick legs covered in dark bristles (macrosetae). Legs are typically pale tan to brown with darker banding or mottling; they are built for high-speed sprinting across the sheet web.
Venom & Safety Information
Venom Information
Neurotoxic venom specialized for paralyzing small insects. It is not considered potent or dangerous to humans.
Medical Significance
Low medical significance. Harmless to humans and pets. A bite may cause minor localized swelling, redness, or itching similar to a bee sting, but bites are rare as they prefer to flee.
Safety Recommendations
No action is usually necessary. If found indoors, they can be easily relocated using a cup and card. They are beneficial to have near gardens to keep insect populations in check.
Habitat & Behavior
Habitat & Range
Common throughout North America. Found in low-lying vegetation, grass, window wells, bushes, and stone foundations. Prefer areas where they can anchor a sheet web to a solid structure or foliage.
Behavior & Temperament
Extremely fast runners but non-aggressive and shy. They spend most of their time at the mouth of their funnel retreat, darting out to grab prey that touches the vibration-sensitive sheet web and quickly dragging it back into the funnel.
Diet & Prey
Generalist predators feeding on crickets, grasshoppers, flies, and other ground-dwelling insects. They use speed to overwhelm prey before the insect can escape the silk sheet.
Seasonal Activity
Most visible in late summer and early autumn when they reach full size and their webs are largest for mating season.
Description
An iconic architect of the morning dew, the Grass Spider is best known for the flat silken sheets it spreads across lawns. These spiders are marvels of speed, capable of crossing their web in a blur to secure a meal. They are an essential part of the backyard ecosystem.
Key Features
Two long, visible spinnerets at the end of the abdomen and two dark longitudinal stripes on the carapace.
Similar Species
Wolf Spiders (Lycosidae) - distinguish by eye size (Wolf spiders have 2 very large eyes) and lack of long spinnerets. Barn Funnel Weavers (Tegenaria) - look similar but prefer indoor environments.
Life Cycle
Females lay disc-shaped egg sacs in protected crevices in late autumn before dying. Spiderlings overwinter in the sac and emerge in spring. Active growth occurs through summer with one generation per year.
Ecological Importance
Vital for natural pest control in gardens and agricultural settings, consuming large quantities of insects that could otherwise damage plants.
Conservation Status
Not evaluated by IUCN; generally abundant and stable throughout North American ranges.
Interesting Facts
The web is not sticky; the spider relies entirely on its incredible speed to catch prey before it hops off the silk. In the morning, dew often collects on their sheets, making hundreds of webs visible across a single field.
Photography Tips
Focus on the 'face' to capture the eye arrangement or use a side profile to highlight the long spinnerets. Low-angle shots of the web with backlighting can show the funnel structure beautifully.
Identified: 2026-06-22T03:54:24.242688