I had a ~~wierd~~ one this year.
 
Went into the colony, which was very strong, only to find several completed
swarm cells, some capped, and some already "open" (emerged or torn open).
Yet the colony had not swarmed.  There were no eggs to be seen, only older
larvae.
 
At the same time, I also saw a number of newer-looking swarm cells, with
nice fat larvae and royal jelly in them.  Why this "second round" of queen
cells was underway, while there were still capped/emerged swarm cells in
the hive is a mystery.  New to me, anyway.
 
Not knowing whether a queen or virgin was present, I left all the queen
cells as they were, and reassembled the hive to let them carry on.
 
That was a couple of weeks ago.  They haven't swarmed, and are putting a
nice crop up in the supers.  Maybe in this case swarming was aborted in
favor of supersedure?
 
Anyone have any ideas on what was going on?
 
tnx
JG