Pachodynerus erynnis (Red-Marked Pachodynerus).
Size: approx. 10 mm. Photo: 09/04/11, noon.

I believe this specimen belongs to the Potter and Mason Wasps. Probably the Red-Banded Mason Wasp Pachodynerus erynnis. This wasp is common in the Southeastern US and often builds nests under the siding boards of buildings. 
bug guide (this photo):
Texas A&M: