Very pretty! I've only seen cuckoo wasps that are either all teal to green or mostly those colors but with a dark red abdomen. I've never seen one with such a pretty blue. It looks like Chrysis angolensis to me. BugGuide doesn't indicate any other similar looking ones to check also. Says it was likely introduced to North America during WWII, and that it parasitizes mud dauber wasp nests.
