Need advice on next step with queenless (?) hive

[Verbify]

One of our hives superceded and the new queen emerged three weeks ago (Sunday will be 21 days and we're sure emergence happened between July 25-26). It appears she either didn't mate or didn't survive. There's no eggs or brood. Since it's so late in the season, the plan is to combine it with another hive via the newspaper method if there is, in fact, no queen. I'm a little afraid to do that without being sure there isn't a virgin or just poorly mated and small queen in there. I can't find her but that's not unusual for my beginner eyes, particularly if a small virgin. Should I stick in a frame of eggs for a few days first to see if they build queen cells as verification? Woukd they do that if a virgin is still hanging around? Is there a way to filter out a virgin when combining? This is our first queen problem do I don't want to jeopardize the host hive's queen when combining. I'd appreciate suggestions on how to proceed.

[Michael Bush]

21 days is kind of the drop dead date but I would check one more time before I assume they are queenless.  A frame of eggs is always a good plan.  That way, if they are queenless they wills start queen cells and you will know.

http://www.bushfarms.com/beespanacea.htm