Although there are several species of sac spiders, the description given is one of the most commonly encountered. The adult female is about 1/8 – 3/8 inch in body length, while the adult male is about 1/8 – 5/16 inch. Their color is yellow to a pale shade of green.
They tend to enter structures in greater numbers in the fall but can be found inside throughout the year. Indoors, they build a silken area in corners of a room in which they rest during the day. It is common to see the sac spider crawling on the ceiling and walls at night, but if startled they will drop to the floor looking for refuge. Outdoors, they typically nest under stones, timbers, debris, corners of windows, and under eaves. These spiders can bite and the typical reaction is redness to the bitten area, a burning sensation, and slight swelling, which may last 24 to 48 hours.
They feed mainly on insects.
The female lays 30 to 48 eggs in a loose mass covered with a thin white silk sac, usually in an indoor area she protects. She can produce several masses in her lifetime. In the New England states the female normally lays her eggs in the fall, they will over winter and the spiderlings will emerge in the spring.