Grass Spider, Funnel Weaver
Agelenopsis species
Agelenidae (Funnel Weavers), Order Araneae
Physical Description
Elongated, somewhat flattened body. The cephalothorax is narrower than the abdomen, featuring two prominent dark longitudinal stripes. The abdomen is tapered at the end with notably long, two-segmented spinnerets that extend visibly beyond the rear.
Size Estimate
Body length 10-20mm; leg span approximately 30-50mm. This appears to be an adult specimen based on the prominent spinnerets and size relative to the leaves.
Coloration & Markings
Generally light brown to grayish-tan. The cephalothorax has two dark parallel stripes running lengthwise. The abdomen typically has a lighter central band bordered by darker, wavy, or mottled markings. Legs are often banded or uniformly brown with visible spines.
Web Type
A flat, sheet-like horizontal web that leads into a silk-lined funnel-shaped retreat at one end. The web is non-sticky; it relies on the spider's speed to intercept prey that lands on the sheet.
Eye Arrangement
Eight eyes arranged in two rows that appear highly curved (procurved), creating a pattern that looks somewhat like a circle or a deep 'U' shape when viewed from the front.
Leg Characteristics
Medium-long, relatively thick legs covered in fine hairs and prominent darker spines (macrosetae). They are positioned to allow for extreme sprinting speeds across the silk sheet.
Venom & Safety Information
Venom Information
Contains agelenitoxins (neurotoxins designed for insects). It is rapid-acting against small invertebrates but has very low toxicity to humans.
Medical Significance
Harmless to humans. Bites are rare because of their timid nature. If a bite occurs, it typically results in only minor redness, itching, or slight swelling similar to a bee sting.
Safety Recommendations
No action is usually needed. If found indoors, they can be easily moved outside using a cup and paper. They are beneficial to have in gardens to protect plants from pests.
Habitat & Behavior
Habitat & Range
Common throughout North America. Found in low-lying vegetation, grass, shrubs (like the boxwood pictured), and occasionally around window wells or foundation crevices of buildings.
Behavior & Temperament
Extremely fast-moving but shy. They remain in their funnel retreat until vibrations on the sheet-web signal prey. They are non-aggressive toward humans and will retreat deep into the funnel if disturbed.
Diet & Prey
Insects such as moths, grasshoppers, flies, and beetles. They use leur speed to dash out, bite the prey to submerge it with venom, and drag it back into the funnel to feed.
Seasonal Activity
Most visible in late summer and autumn when individuals reach adult size and webs become large and conspicuous.
Description
The Grass Spider is a master of speed and architecture. These spiders are famous for creating the dew-covered silk sheets seen on lawns in the morning. They are lightning-fast hunters that provide excellent natural pest control.
Key Features
Long, prominent spinnerets at the end of the abdomen and the two dark parallel stripes on the cephalothorax.
Similar Species
Wolf Spiders (Lycosidae) - distinguished by eye pattern and lack of sheet webs; Fishing Spiders (Dolomedes) - much larger and lack the long spinnerets.
Life Cycle
Females lay eggs in the fall in a protected sac (under bark or in crevices). Adults die off in winter. Spiderlings emerge in spring and mature over the summer months.
Ecological Importance
Significant ecological role in controlling local insect populations in gardens and grasslands. They serve as a vital food source for birds and larger predatory insects.
Conservation Status
Not evaluated by IUCN; generally abundant and widespread with no major threats.
Interesting Facts
The web is not sticky; the spider relies entirely on its record-breaking running speed—up to 1.7 feet per second—to catch prey before it can fly away.
Photography Tips
Focus on the 'face' or the spinnerets to confirm identification. Early morning is best for capturing the dew-covered web which highlights the spider's residence.
Identified: 2026-07-12T08:30:49.392668