Hi Dan,
  I know just what you mean!  I see these mini bees periodically too.   I
think they were food stressed during development and skipped the last
larval instar.  A number of other holometabolous insects do it too.  The
mini bees are always young looking, so I don't think they live to be
foragers.
   I've also seen a hive of mostly mini drones and a few  overworked worker
bees.
Cheers,
Kristina Williams
Boulder, CO

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html