Wall Spider
Oecobius annulipes (?)
This spider was photographed in a Phoenix, Arizona home and is also hosted at Wikimedia.
Family: Oecobiidae
This is probably the most abundant of house spiders in the southwestern United States. Full grown they are 3 mm or less in length ... too small to bite through human skin. Their webs are positioned in corners and along window sills where they catch minute crawling or flying insects. The webs readily gather dust and are the bane of fastidious housekeepers. The can also be found on outside walls and on surfaces of boulders in more natural habitats.