While checking out my bees today, I pulled out the #1 frame in the brood
chamber and on the outer side, I saw an unusual insect.  This insect looked
very much like a honeybee except that it was about 25% larger and had a
fairly large, black, somewhat rounded, abdomen.  Within a couple of seconds
of pulling out the frame, it flew off.  It flew more like a housefly than a
bee; that is, its legs and abdomen were not noticably hanging down and it
seemed to be faster.  It was on a cell of nectar/honey; there was not brood
on that side.
 
     I checked out "Honeybee Pest, Predators and Diseases" but didn't find
anything that resembled this thing.  Anyone have any suggestions?
 
     Geographically, I am located between Baltimore, MD and Washington D.C.,
USA.
 
     Any thoughts?
 
     Thanks,
     David Morris