Once I determined I was missing a bee queen in Gertrude hive, it was time to add a new one.
The queen travels in a plastic container with a worker bee and a marshmallow stopper at one end.
Once placed inside the hive, it will take worked bees a couple of days to eat through the marshmallow to release the queen. By then, they should be familiar with her smell and open to accepting her into the colony.
Long live the queen!