American Grass Spider, Grass Spider, Funnel-Weaver
Agelenopsis pennsylvanica
Agelenidae (Funnel-Weavers), Order Araneae
Physical Description
The spider has an elongated, tapered abdomen, a distinct striped cephalothorax, and prominent spinnerets visible at the rear. The body is covered in fine setae (hairs), giving it a slightly velvety or dusty texture.
Size Estimate
Body length is approximately 10 to 18 millimeters, with a leg span of roughly 25 to 40 millimeters, typical of an adult medium-sized grass spider.
Coloration & Markings
Predominantly brown and grayish tones. The cephalothorax features two dark longitudinal stripes running parallel from the eyes to the rear. The abdomen has a central lighter band bordered by darker mottled brown or black chevron patterns.
Web Type
Builds a sheet web close to the ground in grass or low vegetation, featuring a tubular retreat or funnel at one end where the spider waits for prey.
Eye Arrangement
Eight eyes arranged in two distinct horizontal rows of four, typical of funnel-weaver spiders, with the posterior row slightly recurved.
Leg Characteristics
Long, slender legs with distinct spines and faint darker banding. The legs are typically spread wide in a flat, sprawling stance when resting on the web.
Venom & Safety Information
Venom Information
Neurotoxic venom primarily used to immobilize small insect prey. It is not potent or specialized for defense against large vertebrates.
Medical Significance
Harmless to humans. Their chelicerae are generally too weak to puncture human skin, and bites are extremely rare, resulting in mild, localized irritation if they occur at all.
Safety Recommendations
No special safety precautions are necessary. If found indoors, they can be gently scooped up and relocated to an outdoor garden.
Habitat & Behavior
Habitat & Range
Found across North America, commonly in lawns, meadows, fields, gardens, and occasionally around the foundations of homes.
Behavior & Temperament
Extremely fast runners when outside the web. They are non-aggressive, retiring creatures that quickly retreat into their funnel when disturbed.
Diet & Prey
Generalist predators feeding on various ground-dwelling and flying insects, such as grasshoppers, flies, beetles, and moths.
Seasonal Activity
Most active during the warm summer and early autumn months, with mating occurring in late summer before adults die off with the first frosts.
Description
The American Grass Spider is a familiar and harmless resident of lawns and gardens across North America. Easily recognized by the signature funnel-shaped web it spins in thick grass, this swift hunter spends its days waiting near the entrance of its retreat for an unsuspecting insect to land on the horizontal sheet web.
Key Features
Distinguished by the prominent, elongated spinnerets at the rear of the abdomen, dark longitudinal stripes on the cephalothorax, and the characteristic sheet web with a funnel retreat.
Similar Species
Wolf spiders (Lycosidae), which do not build webs and have different eye arrangements, and hobo spiders (Tegenaria agrestis), which have a more uniform brown coloration without the distinct cephalothorax stripes.
Life Cycle
Females construct silken egg sacs in sheltered spots during autumn. Spiderlings hatch in spring, undergoing multiple molts to reach maturity by late summer.
Ecological Importance
Acts as an effective natural pest control agent by regulating populations of grasshoppers, beetles, and various garden insects.
Conservation Status
Not evaluated by the IUCN, but populations are widespread, stable, and highly abundant.
Interesting Facts
Grass spiders possess some of the fastest acceleration rates among terrestrial animals when launching themselves from their webs to capture prey.
Photography Tips
Best photographed in natural outdoor settings on their webs. Use a macro lens from a low angle, natural side lighting, and a fast shutter speed to capture details without disturbing them.
Identified: 2026-08-07T23:16:11.530139