
My friend Alex recently bought a new house. She's getting the full experience of being responsible for the animals that let themselves inside. I have to say I'm very proud of her--she was quite aware that there were at least two species in her bedroom, but did not kill them since they will do more good than harm. I identified one right away as a
yellow sac spider, but I had more trouble with this one.
My friend Keith identified it for me: it's a broad-faced sac spider,
Trachelas tranquilis. It looks fairly similar to the
woodlouse hunter but is not closely related. Like the yellow sac spider it makes a silk refuge to hide in during the day and actively hunts at night. The entry on bug guide adds "...will frequently enter houses by accident in the autumn," which also helps identify it. This individual gets its studio-quality portrait from posing on the window blinds (it was trying to hide and I spooked it out to photograph it).