Did I goof the top bar hive?

The bees stopped buzzing around the top bar comb, so today I went to clean up and store the comb.  In the no longer sticky comb was bee bread and some dark spots.

 Curious, I took a close up look:

Dead larvae!
I can come up with three ways the larva got there.
1.  They were there all along from a year ago.  I think this is quite unlikely as the comb appears new and I believe I would have seen them before when I cleaned up.
2.  There was a queen in the hive and things were going just as they should.  This is possible, but before I dismantled the top bar hive I inspected carefully and did not see a queen, although I did not see the larvae, either.  And don't forget the behavior of the clustered bees I failed to collect.  Tom Seeley says it is unlikely a swarm would stick around and then leave for new quarters without a queen.
3.  Most likely, these are drone larvae from a laying worker.  At least I hope that's the explanation.
In any case, a learning experience and another reminder of my ignorance.
I will post again soon concerning the inspection of all three hives done five days ago.