Where is the queen?

The queen is in there somewhere!

But I'm not experienced enough to spot her in a broiling mass of bees on a frame.

I have opened the hive a couple of times and looked for eggs.  They're there - but very hard to spot, especially with my bi-focals.  And there's quite a bit of uncapped brood - ie. eggs that have developed into larva in cells, but the cell has not yet been capped by the workers.

If I could find the queen, I might be able to mark her.  But a) I can't see her (she may be lurking on the floor of the hive); and b) even if I could, I wouldn't know how to.

Lots to learn.