This morning I went in to prepare the queenless hive for queen introduction. I performed a more detailed and thorough examination, and I suspect that the old queen failed due to old age or sickness. There was brood, some capped pupae and larvae, but the pattern was spotty, and there were zero eggs. So she must have become sick and started laying poorly before she either died or was killed by the bees. There were a few queen cells, which I removed. I put a sugar syrup feeder on top, and they should readily accept the new queen when I introduce her.
After putting the new queen in the hive for 2-3 days, I will manually introduce her into the hive. This will allow me to watch the reaction of the bees as she is released onto the comb. If they attack her, I can take remedial action to correct the situation. If not, at least I will be assured that she is alive and ready to start laying eggs.
The queen is coming via UPS, and is being sent to vinfille at work, since she will be there to receive the new queen. I do not want the UPS person to drop off the new queen at our house, where she will be sitting outside for who knows how long before we get home. I figure the caged queen should be a good conversation piece sitting on her desk.