Grass Spider, Funnel Weaver
Agelenopsis pennsylvanica
Agelenidae (Funnel-Weavers), Order Araneae. Key family characteristics include three pairs of spinnerets with the posterior pair notably elongated, and an agile running habit.
Physical Description
Elongated body shape with a tapered brown abdomen featuring distinct lateral striping, and a carapace marked by two dark longitudinal stripes running parallel along the top. Noticeably long spinnerets extending past the rear of the abdomen.
Size Estimate
Body length approximately 10 to 18 mm, with a leg span reaching up to 40 mm. This specimen appears to be a subadult or adult female.
Coloration & Markings
Predominantly brown and tan with characteristic dark brown longitudinal bands running the length of the cephalothorax and continuing along the sides of the dorsal abdomen.
Web Type
Builds a horizontal sheet web ending in a tubular retreat or funnel structure where the spider lies in wait, constructed low in grass or near foundations.
Eye Arrangement
Eight eyes arranged in two distinct, slightly curved rows of four, typical of the Agelenidae family.
Leg Characteristics
Long, spiny legs adapted for extremely rapid running across grass and sheet webs, lacking specialized heavy banding but uniform brown with visible spines.
Venom & Safety Information
Venom Information
Neurotoxic venom designed for rapid immobilization of insect prey, but generally weak and ineffective against human skin.
Medical Significance
Harmless to humans. Bites are rare, usually only occurring if the spider is trapped against the skin, and result in mild, localized discomfort similar to a mosquito bite.
Safety Recommendations
No special safety measures required. If found indoors, it can be easily gently relocated outside using a cup and a piece of paper.
Habitat & Behavior
Habitat & Range
Found throughout North America in lawns, fields, gardens, and occasionally straying indoors near ground level or basements.
Behavior & Temperament
Active ground runner and web ambusher. Extremely fast and skittish; will typically flee rapidly toward its funnel retreat when disturbed rather than show aggression.
Diet & Prey
Primarily feeds on ground-dwelling insects, grasshoppers, beetles, and flies that blunder into the non-sticky sheet web.
Seasonal Activity
Most active during late summer and autumn when mature adults wander in search of mates, often becoming more noticeable around homes as temperatures drop.
Description
The grass spider is a quintessential backyard inhabitant, instantly recognizable by the broad sheet webs it spins across lawns and low vegetation. With its characteristic racing stripes and lightning-fast speed, it serves as an efficient and harmless household or garden guardian.
Key Features
Prominent, elongated posterior spinnerets, two dark parallel stripes on the cephalothorax, and construction of a horizontal sheet web ending in a funnel.
Similar Species
Wolf spiders (Lycosidae), which do not spin webs and carry their egg sacs on their spinners, and hobo spiders (Tegenaria agrestis), which share similar coloration but differ in geographic range and subtle structural details.
Life Cycle
Females construct tough, disc-shaped silk egg sacs in sheltered crevices during autumn, where eggs overwinter until spiderlings hatch in spring.
Ecological Importance
Acts as a primary controller of lawn and garden insect populations, regulating pest numbers naturally without harming the environment.
Conservation Status
Secure and widespread; not threatened, highly adaptable to human-altered landscapes.
Interesting Facts
Grass spiders are among the fastest terrestrial invertebrates relative to their size, capable of executing sudden high-speed sprints across their webs to intercept prey.
Photography Tips
Photograph from above or the side to capture the distinctive dorsal stripes and long spinnerets. Natural outdoor macro lighting works best.
Identified: 2026-10-13T17:19:59.649877