Brachymyrmex is one of those genera that is really easy (for me, anyway) to identify to genus, but almost impossible to identify to species. The only species I was able to put a name on was Brachymyrmex cavernicola, a cute little bugger that looks more like a Paratrechina than a Brachymyrmex until you count the antennal segments. The last taxonomic revision was in 1923 (Santschi) so it is definitely due for another one. Luckily, it looks like Vinda Maharajh, a PhD student at the University of Florida, is working on one. I sent him a bunch of my samples last week and wish him luck. If you have any Brachymyrmex specimens lying around, you might consider sending them on over.