Grass Spiders, Funnel-Web Spiders
Agelenopsis species
Family Agelenidae (Funnel Weavers), Order Araneae
Physical Description
These spiders feature an elongated, slightly flattened cephalothorax and a narrowing, oval-shaped abdomen. They are moderate in build with a visible pair of prominent, long posterior spinnerets that extend from the end of the abdomen.
Size Estimate
Body length typically 10-20mm with a leg span often reaching 30-50mm. The specimen in the image appears to be an adult or sub-adult based on leg proportions relative to the web detritus.
Coloration & Markings
Typically brown, tan, or grayish with two prominent dark longitudinal stripes running down the cephalothorax. The abdomen usually has a lighter central stripe with darker, sometimes chevron-like markings on the sides.
Web Type
Funnel web. They construct a flat, non-sticky sheet of silk with a funnel-shaped retreat at one end. This image shows characteristic dense, messy webbing in a structural corner, typical of indoor or garage sightings.
Eye Arrangement
Eight eyes arranged in two rows, often appearing to form a crescent or slightly curved pattern. The eyes are relatively small compared to wolf spiders.
Leg Characteristics
Long, tapered legs with many prominent bristles (spines). They lack the thick hair padding of wolf spiders and are built for high-speed running across their sheet webs.
Venom & Safety Information
Venom Information
The venom is primarily used to paralyze insect prey. For humans, it is not considered medically significant and is generally comparable to a mild bee sting.
Medical Significance
Low significance. Bites are rare due to their skittish nature. Symptoms are usually limited to localized pain, redness, and minor swelling. No special medical treatment is typically required.
Safety Recommendations
If found indoors, they can be safely relocated using the 'cup and cardboard' method. To prevent entry, ensure window screens are intact and gaps around doors are sealed. Wear gloves when cleaning out old webbed areas in garages or sheds.
Habitat & Behavior
Habitat & Range
Common across North America; found in tall grass, bushes, and structural crevices like window wells, corners, and porches. They often move indoors when temperatures drop or for mating.
Behavior & Temperament
Extremely fast-moving but generally shy. They rely on speed to retreat into their funnels at the slightest vibration. They are non-aggressive and will only bite if pinned or handled roughly.
Diet & Prey
Generalist predators eating various insects and other spiders. They detect vibrations on their non-sticky silk sheet and rush out at high speed to subdue prey with venom before dragging it into the funnel retreat.
Seasonal Activity
Populations peak in late summer and early autumn when males are often seen wandering in search of females.
Description
A common sight in late summer and autumn, the Grass Spider is a master of structural webbing. While they are often feared for their speed and resemblance to more dangerous spiders, they are beneficial neighbors that provide excellent natural pest control around homes and gardens.
Key Features
Distinctive long posterior spinnerets, two dark stripes on the cephalothorax, and the construction of a sheet web with a funnel retreat.
Similar Species
Wolf Spiders (Lycosidae) are similar in color but have much larger eyes and lack the long spinnerets. Hobo Spiders (Eratigena agrestis) can look similar but usually have more uniform leg coloration and different abdominal markings.
Life Cycle
Females lay egg sacs in autumn, usually in protected crevices or under bark. Adults typically die off in late autumn/winter. Spiderlings emerge in the spring. They usually live for approximately one year.
Ecological Importance
Highly effective at controlling populations of flies, crickets, and small moths near human structures, serving as a first line of defense against household pests.
Conservation Status
Not evaluated by IUCN, but currently widespread and abundant with no known major threats.
Interesting Facts
Despite their speed, these spiders do not have sticky webs; they rely entirely on their lightning-fast reflexes to catch prey before it can fly or crawl off the silk sheet.
Photography Tips
Focus on the dorsal (top) view to capture the stripes on the head and the length of the spinnerets. Use a high shutter speed if the spider is moving, as they are exceptionally fast.
Identified: 2026-06-13T03:40:47.107968