Site Help: what is it?, 1 by mterre

mterre wrote:
We found this on a sandy leach field, it's about an inch long,maybe inch and a half-- rather big for a bee, i first saw it on milkweed, seeming to lay eggs, (that kind of motion, anyway,) pulsing it's abdomen. i then found another one on a clod of dirt, doing the same. It then was on a Queen Anne's Lace.
At first we thought it was a squash vine borer, then moved onto European Hornets, but the coloring is wrong, or at least compared to the webshots we've found....