Yellow sac spider

Cheiracanthium mildei is a European species introduced into North America in the 1940s.
Although they are sometimes seen during the day, they are nocturnal spiders. They do not weave webs, but hunt actively, chasing their prey across walls and ceilings.

C. mildei may bite if it feels threatened. There are few known cases of bites in Quebec, however, since the species is fearful and shy. Victims generally show only minor symptoms such as local redness, swelling, itching and a burning sensation at the site of the bite. The wound usually heals within a few weeks.