No, these are not beetle larvae, I'm quite sure about that.

I've also considered freezing, but it would be good to find out, what kind of creatures are these (as some insect eggs can survive extreme cold). Also, how should I clean humidor? It is too big to fit in the freezer, and I'm afraid that just cleaning it with a damp cloth wouldn't remove all the eggs which may be there. Any chemical agent, which wouldn't damage the cedar? Maybe vinegar solution?

Also, does freezing have any effect on the taste of the cigars? Is it worth freezing all new cigars before placing them in the humidor, just in case?