I "found" a slide of another image of this Rophitinae. To me it seems the best, showing the mid and hind legs very well as well as a toothed mandible. And, the abdomen seems to have some light crossbands that are not evident in the other pictures.
On Friday we plant to visit the CU Museum entomology collection and check out this bee against their four Xeralictus specimens, two of each species. I am just hoping that one of the specimens will prove to be a male. It will be interesting to make the comparisons.

Update, 27 June 2009. After our visit to the CU Museum and a subsequent visit to the CU Library where we had ordered Snelling and Stage, 1995, I am cautiously optimistic that this bee is a Xeralictus. Of the four bees in the museum collection one of them, X.bicuspidariae, was a male. It is very difficult to see traits on a mounted bee where all the parts are scrunched up. What we could ascertain was that the pilosity of the abdomen was exactly as on our picture with the short basal bands of short white hairs. The hind tibia and basitarsus were similar, but we could not see the coxa or femur. The mandible had two teeth, but they were not exactly as indicated in our photo. Coloration did not match our photo. This comparison was rather discouraging.
But Snelling and Stage's revision, 1995, proved to be helpful. It illustrated the frontal and lateral view of the X. timberlakei head showing a two-pronged structure above the tongue exactly as in our photo, and the mandible does show two teeth, though not exactly as in our view. The long antennae is similar. The description of the pilosity matched almost exactly, not only the abdominal hairs but also long moderately dense hairs on gena, side of propodeum and outer side of metatibia and tarsi.
Hence my optimism. But not enough for certainly by a long shot.