This is Hogna helluo. It is the second largest species of wolf spider in the United States. I've been looking for one of these for the longest time, and today while I was out fossil hunting, I found one. This gal was about the size of a half dollar, about an inch and a half in diameter, including legs. Definitely the largest wolf spider I have ever seen.
The carapace of Hogna helluo is characterized by a clearly defined medial stripe from a point between the middle pair of eyes nearly to the point at which the carapace joins the abdomen. The abdomen has a broader light stripe with a darker narrow and tapering form like the head of a lance or a stone arrow point. The underside of the cephalothorax is solid black, but the underside of the abdomen may be spotted with lighter colored patches.
This species does not dig tunnels but may create shelters under rocks and similar natural features. H. helluo frequently enters houses with the arrival of lower temperatures in autumn. They are inside only in search of warmer temperatures and make every possible effort to stay away from people.
Raynox DCR-150 mounted on my Panasonic FZ8.