Funnel web weavers (Family Agelenidae) are small to medium sized spiders often found in grassy fields, low shrubbery, or living among leaf litter in forests. They spin sheet webs of nonsticky silk with a characteristic funnel extending off to one side. The funnel is where the spider hides while awaiting prey. There is a 3-dimensional barrier web spun above the sheet web, and when a prey item falls through onto the sheet web, the spider quickly runs out and bites its victim, then drags it back to the funnel to feed. These sheet webs are nearly invisible unless covered with dewdrops on a cool morning, and the spider can move very quickly over the surface. It almost looks as if the spider is walking on air. There are over 400 North American species.

Spiders in the most common genus, Agelenopsis, are commonly called "grass spiders," after their habit of building their combination sheet-and-funnel webs in grass and low shrubs.