I think this is Aulocara elliotti, although this individual appears to be quite different than most of the bugGuide pics of that species. The pale median stripe, originating at the pronotum, runs the entire length of the forewing. The black vertical streak above the mandible, of A. femoratum, appears to be absent. I think the black knee indicates that this is a male? A. elliotti was rather abundant at this site, and this was the only individual like this that I saw. Unfortunately, only one shot before it escaped. shortgrass prairie-sandsage grassland ecotone.