Grass Looper (Family Erebidae)
The BugLady is pretty sure that this is a Forage Looper (Caenurgina erechtea) instead of the very similar Clover Looper (C. crassiuscula). Both occur across North America and southern Canada (not so much in the Great Plains), right up to the southern edge of the boreal forest. The GL likes moist, well-vegetated, open fields, edges, and disturbed vegetation.