Grass Spider, Funnel Weaver
Agelenopsis spp. or Tegenaria domestica (Common Grass Spider or Barn Funnel Weaver)
Agelenidae (Funnel Weavers), Order Araneae. Key family characteristics include three pairs of spinnerets with the posterior spinnerets being notably elongated, and building sheet webs that lead into a tubular retreat.
Physical Description
Elongated body shape with a distinct cephalothorax featuring prominent dark longitudinal bands. The abdomen is oval, covered in fine setae, and shows patterned striping. Proportions show robust legs adapted for fast running across flat surfaces.
Size Estimate
Body length is approximately 8 to 15 millimeters with a leg span reaching up to 30 to 40 millimeters, depending on the specific sex and maturity.
Coloration & Markings
Tan to brown coloration with distinctive dark brown or black longitudinal stripes running along the dorsal side of the cephalothorax. The abdomen features a central lighter band bordered by darker mottled patches.
Web Type
Builds a horizontal sheet web that does not stick, featuring a funnel-shaped retreat at one edge where the spider waits for prey.
Eye Arrangement
Eight small eyes arranged in two slightly curved horizontal rows across the anterior portion of the cephalothorax.
Leg Characteristics
Long, tapering legs equipped with numerous prominent spines, typical of active running spiders that rely on speed rather than sticky webs to capture prey.
Venom & Safety Information
Venom Information
Contains mild neurotoxic and proteolytic venom designed to subdue insect prey. It is generally harmless to humans and large pets.
Medical Significance
Not medically significant. Bites are extremely rare, usually only occurring if the spider is trapped directly against the skin. Symptoms are generally limited to minor, transient localized pain or mild swelling similar to a mosquito bite.
Safety Recommendations
Keep living areas clean, seal cracks around doors and windows, and gently relocate wandering individuals outside using a cup and paper.
Habitat & Behavior
Habitat & Range
Found across North America, Europe, and parts of Asia. Prefers grassy fields, lawns, and low vegetation outdoors, but frequently wanders indoors into homes, basements, and kitchens looking for mates or shelter.
Behavior & Temperament
Active ground hunter and web builder. Typically very fast and skittish, preferring to flee rather than fight when disturbed, though females guarding egg sacs may show defensive posturing.
Diet & Prey
Generalist predator feeding on a wide variety of ground-dwelling insects including flies, beetles, ants, and grasshoppers.
Seasonal Activity
Most active during late summer and autumn when adults reach full size and males actively wander in search of females.
Description
This swift and agile spider is a common inhabitant of both wild grasslands and human dwellings. Known for constructing intricate sheet webs with funnel retreats, these spiders spend most of their time hidden or sprinting across surfaces with remarkable speed.
Key Features
Long, prominent spinnerets at the rear of the abdomen, dark longitudinal stripes on the carapace, and rapid running behavior.
Similar Species
Wolf Spiders (Lycosidae) which lack the elongated spinnerets and funnel webs, and the Brown Recluse (Loxosceles reclusa) which lacks stripes and has a characteristic violin pattern.
Life Cycle
Mates in late summer. Females construct disc-shaped silk egg sacs in sheltered areas during autumn, where eggs overwinter before spiderlings emerge in the spring to disperse via ballooning.
Ecological Importance
Serves as an important natural controller of insect populations in both agricultural and residential settings.
Conservation Status
Not threatened or endangered; populations are abundant and widespread globally.
Interesting Facts
Grass spiders possess some of the fastest acceleration rates among terrestrial animals when launching towards prey landing on their sheet webs.
Photography Tips
Capture top-down shots to clearly show the cephalothorax stripes and abdominal patterns, using natural macro lighting while avoiding sudden movements that trigger their escape.
User Notes
Found crawling in my kitchen floor
Identified: 2026-08-25T01:56:37.678938