I still have quite a few of these colonies and they seem to be doing a little better. They aren't growing much, but the deaths seem to have stopped.
One of the queens that died had what looked like some sort of white fungus mixed with some cotton strands growing on its thorax. The fungus kept growing larger until the queen was finally found dead. This isn't the first time I found what looks like fungus growing on the thorax of a Pheidole xerophila queen.
