Grass Spider, American Grass Spider, Funnel-Web Weaver
Agelenopsis sp.
Agelenidae (Funnel Weavers), Order Araneae
Physical Description
Elongated, somewhat flattened cephalothorax with two prominent dark longitudinal stripes. The abdomen is tear-drop shaped, often hairy, and ends in two notably long, protruding spinnerets which are characteristic of this genus.
Size Estimate
Body length typically 10-20mm; including leg span, they often reach the size of a half-dollar (approx. 30-50mm). This specimen appears to be an adult.
Coloration & Markings
A mix of brown, tan, and gray. Two distinct dark longitudinal bands run the length of the carapace, and the abdomen often features a lighter central band with darker chevron-like patterns.
Web Type
Builds a flat, sheet-like horizontal web that tapers into a funnel-shaped retreat in a corner or crevice. The web is non-sticky, relying on the spider's speed to intercept prey.
Eye Arrangement
Eight eyes arranged in two rows that are curved, often appearing as three rows (2-4-2). Specifically, the eyes form a 'frowny' or deeply procured secondary row.
Leg Characteristics
Long, hairy legs with visible spines (macrosetae). Legs are typically pale brown and may show subtle darker banding. They are designed for high-speed running across the web surface.
Venom & Safety Information
Venom Information
Possesses a harmless neurotoxic venom used to paralyze small insects. It is not considered toxic or dangerous to humans.
Medical Significance
Low medical significance. Bites are rare due to their timid nature. If bitten, symptoms are usually less severe than a bee sting, involving minor swelling or localized itching.
Safety Recommendations
No special safety measures are needed. If found indoors, they can be easily moved outside using the 'cup and paper' method, though they are difficult to catch due to their speed.
Habitat & Behavior
Habitat & Range
Found throughout North America. They prefer low-lying vegetation, grass, window wells, and crevices around building foundations or doorways.
Behavior & Temperament
Extremely fast runners and shy. They spend most of their time vibrating at the mouth of their funnel, retreating deep inside at the slightest vibration. They are not aggressive toward humans.
Diet & Prey
Generalist predators feeding on various crawling and flying insects like crickets, moths, and flies that land on the horizontal sheet of the web.
Seasonal Activity
Most visible in late summer and autumn when they reach adult size and their large webs become carpeted with morning dew.
Description
The Grass Spider is a common sight in late summer gardens. Easily identified by its remarkable speed and 'tail-like' spinnerets, it serves as a master of the funnel-web, waiting patiently for a vibration to signal a meal. Though often mistaken for more dangerous spiders, it is a beneficial and harmless neighbor.
Key Features
The most diagnostic features are the exceptionally long, two-segmented spinnerets extending from the rear of the abdomen and the two dark parallel lines on the cephalothorax.
Similar Species
Often confused with Wolf Spiders (Lycosidae), which lack the long spinnerets and do not build webs, and House Spiders (Tegenaria/Eratigena), which have different eye patterns and markings.
Life Cycle
Females lay egg sacs in autumn, usually in protected crevices or under bark. The female dies shortly after. Spiderlings hatch in spring and often disperse via ballooning.
Ecological Importance
Significant natural pest control agents, consuming vast quantities of garden and household pests like flies, ants, and beetles.
Conservation Status
Not evaluated by IUCN; generally considered common and widespread with stable populations.
Interesting Facts
The web is not sticky; the spider relies entirely on its record-breaking speed to catch prey before it can escape the silk sheet. They are among the fastest spiders in North America.
Photography Tips
Focus on the tail-like spinnerets for identification. Because they are shy, use a zoom lens from a distance to capture them sitting at the mouth of their funnel retreat.
Identified: 2026-06-28T00:25:20.477044