I almost posted that this species was impossible to identify with confidence to anything other than tribe...then I saved the pic and took a closer look. I'm 95% certain (you can rarely be 100% certain of a species ID from a photo with pompilids) that this is Anoplius lepidus atramentarius. They are fairly common in the southern states and it had several structural clues visible. When I enlarged the photo and did some things with the contrast I could see pygidial bristles (characteristic of Anoplius females) and a tarsal comb. It's also obviously all dark with it's minute pubescence rather strongly reflecting bluish. I was able to vaguely make out a clypeal emargination, a slightly angulate rear pronotal margin, and a lack of abundant erect hair. Only two subgenera in the genus Anoplius commonly have an emargination in the clypeus: Lophopompilus and Notiochares. Lophopompilus always has abundant erect hairs and almost always has the rear pronotal margin arcuate (often strongly so). Notiochares has two nearctic species and only one is found in Arkansas, A. lepidus atramentarius. The prey you mentioned is also good supporting evidence, many species in this genus prey on Lycosids but A. l. atramentarius has only ever been recorded taking Lycosids as prey. Sorry about the long explanation but with a genus as difficult as Anoplius I feel I should give ample explanation.

i can understand how difficult these can be to identify from pictures... i have a hard time getting it past pompilid when it is right in front of me. also, i am relly happy about the long explanation, as i feel i might have learned something. i added one more photo that i think i resized better, and because i did not see anymore on the site. so Mr. Fensler, i thank you for the info.

I've gone through my collection of spider wasps and have produced some rather poor, but adequate images (I don't have great equipment). I've produced a guide page for this species but haven't had a chance to put any info in it.

You'll see that the individuals in the photos (mine and yours) look VERY similar. I'd still use just that 5% sliver of caution, since the individual you saw was ID'd from a photo (which is tough to do from normal photos...and by normal I mean those not taken from the eye pieces of a microscope).