Yellow Sac Spider (Silken Retreat/Egg Sac)

Found commonly inside homes (corners where walls meet ceilings, behind furniture, in folds of curtains) and outdoors in curled leaves or vegetation.

Carnivorous; feeds on a variety of small household insects, arthropods, and other spiders.

Unlike web-weaving spiders, they are active nocturnal hunters that forage for food. They spin small, white, tent-like silken sacs (like the one pictured) to rest in during the day, to molt, or to protect their eggs.

Benefits: Effective pest control that reduces populations of flies and other insects. Risks: They are responsible for a significant number of indoor spider bites; bites are painful (similar to a bee sting) and can cause redness or swelling, but are rarely medically serious.