I went to check on this queen a few days ago, and found she already had workers. This was about as fast as my P. californicus colonies got their first workers, in just over three weeks.
Since this is one of my favorite species, or at least very close in relation, I was pretty happy to see workers and right away started taking pictures. To my horror, I found a tiny little light red mite walking around in the tube. When I looked closer, I noticed one on the thorax of the queen and two of the workers. I quickly setup a shallow container lined with talcum powder, and dumped the whole colony, brood and all into this container. One by one I took out mite-free workers and clumps of eggs and put them into a fresh test tube. It wasn't too hard to smash the mite riding on the queen's thorax with a forceps, but the two little 2.5 mm nanitic workers were not as easy.
Eventually I got them off by pinning them up against the edge of the container and gently rubbing a 000 size specimen mounting pin on them until the mite was knocked loose. I then brushed it away from them and smashed it. I also found a mite on two of the pupae, and one mixed in with their eggs. Those were not as hard to remove, as I just speared them with the pin. All of this was done under my microscope, and would have been impossible without it. A little later I found another mite walking around in the test tube, and I got lucky and was able to smash it with a forceps first try.
Since I don't know what species these mites are, and have no idea how big their eggs might be, I'm checking the colony every day for new mites, and I plan to kill them before they mature and lay more eggs.