How large is the day retreat typically spun by a mature female Yellow Sac Spider?

Noticing these pale, often slightly irregularly shaped silk retreats, a mature female's day retreat often measures about half an inch in length.

The size of the silken day retreat, or sac, is directly proportional to the size of the spider inhabiting it. Since Yellow Sac Spiders are nocturnal and hide during the day, the sac must be large enough for comfortable concealment. Specifically, the retreat constructed by a mature female is substantial enough for her to curl up inside completely. This dimension is generally reported as measuring approximately half an inch in length. Inspecting an area for these pale, slightly irregular, papery-feeling silken envelopes is often a more effective way to locate a resting Yellow Sac Spider than actively searching for the spider itself.