Prompted by dirtdorphins and GrammaChar comments, I did a bit more scouting on the internet. The first two links cover the Xylocopa-mexicanorum:
http://bugguide.net/node/view/...
http://www.inaturalist.org/tax...
The next two links cover the Xylocopa-micans:
http://bugguide.net/node/view/...
http://www.inaturalist.org/tax...
The last contains a discussion of carpenter bees, but also has an excellent picture at the start of a Xylocopa-micans, which looks rather close to the bee in GrammaChar's images.
https://en.wikipedia.org/wiki/...
