Grass Spider, Funnel Weaver, Sheet Weaver
Agelenopsis species (likely A. pennsylvanica or A. naevia)
Agelenidae (Funnel Weavers), Order Araneae. Key characteristics include long, prominent spinnerets and a flat sheet-like web with a retreat.
Physical Description
A medium-sized spider with an elongated, pear-shaped cephalothorax and an oval abdomen tapering to two long, noticeable posterior spinnerets. The body has a hairy (setose) texture and a generally robust, athletic build suitable for fast running.
Size Estimate
Estimated body length 10-20mm with a leg span of approximately 35-50mm. This appears to be an adult specimen, possibly a male given the elongated legs and activity outside of a web.
Coloration & Markings
Features two dark longitudinal stripes running down the cephalothorax, separated by a lighter tan or gray median band. The abdomen typically displays a darker chevron or mottled pattern down the center, flanked by lighter tan or brown sides.
Web Type
Builds a non-sticky horizontal sheet web that leads into a funnel-shaped retreat at the side or center. These are usually found in low vegetation, grass, or corners of structures.
Eye Arrangement
Eight eyes arranged in two rows of four, with the rows being strongly procurved (arched upward), creating a pattern that looks somewhat like a circle or two tiers when viewed from the front.
Leg Characteristics
Long, thin, and bristly legs designed for speed. They often exhibit faint dark banding or spotting and are held in an outward, sprawled posture that allows for rapid movement across the top of their webs.
Venom & Safety Information
Venom Information
The venom is a complex mixture containing agelenitoxins (neurotoxic), but it is specifically evolved for paralyzing small insects and possesses negligible potency in humans.
Medical Significance
Low medical significance. Bites are rare and typically result in minor localized redness and swelling similar to a bee sting. They are not considered dangerous to healthy humans or pets.
Safety Recommendations
Relocate indoor specimens using the 'cup and paper' method. To prevent entry, ensure window screens are intact and seal gaps in door frames. No special first aid is required beyond cleaning a bite with soap and water.
Habitat & Behavior
Habitat & Range
Found throughout North America. Preferred habitats include grassy fields, gardens, shrubs, and window wells. They often wander into homes during late summer and autumn.
Behavior & Temperament
Extremely fast runners and active hunters within their web range. They are generally shy and will retreat into their funnel at the slightest vibration. They are not aggressive toward humans and usually bite only if pressed against skin.
Diet & Prey
Generalist predators that eat a variety of ground-dwelling insects, including grasshoppers, beetles, and moths that fall onto their sheet webs. They detect vibrations and rush out to subdue prey quickly.
Seasonal Activity
Most visible in late summer and early autumn (August through October) when they reach maturity and males wander in search of mates.
Description
Grass spiders are the speedsters of the backyard. Often noticed when the morning dew highlights their expansive sheet webs, these spiders are characterized by their racing stripes and remarkably long spinnerets. They are beneficial neighbors that provide excellent natural pest control.
Key Features
Long, two-segmented posterior spinnerets that extend past the end of the abdomen and two dark parallel stripes on the cephalothorax.
Similar Species
Often confused with Wolf Spiders (Lycosidae), which lack the long spinnerets and have larger eyes, or the non-native Hobo Spider (Eratigena agricola), which lacks the distinct stripes on the cephalothorax.
Life Cycle
Females lay egg sacs in crevices or under bark in late autumn before dying. The spiderlings hatch in spring. Lifespan is typically one year, with a single generation per year.
Ecological Importance
Crucial for controlling populations of agricultural and garden pests. They serve as a vital food source for birds, wasps, and larger predatory insects.
Conservation Status
Not evaluated by IUCN, but populations are stable and widespread; they are common in urban and suburban landscapes.
Interesting Facts
Despite their webs, they do not use glue; they rely entirely on their incredible speed (among the fastest of all spiders) to catch prey before it leaves the non-sticky sheet.
Photography Tips
Focus on the top of the cephalothorax to capture the 'racing stripes' and include the rear of the abdomen to show the long spinnerets, which are diagnostic for this family.
Identified: 2026-07-02T15:06:16.696545