Apparently, the dogs who were attacked by the Africanized bees lived in a house where there was a huge hive--one was in the attic and the other was in a broken down wall. I am happy to say that the bees on our flowering shrubs have been behaving like perfectly normal bees. I found an excellent article on their behavior at this web site: http://labs.biology.ucsd.edu/nieh/TeachingBee/africanized.htm
I think it is certainly not good to over-react to the whole "killer bee" thing, but it is foolish and potentially dangerous not to be alert and extremely careful.
With my wild hive under my shed, the first thought was Africanized, I slowly tested them to see how they acted. I was relieved, in more ways then one when they did not get aggressive. At this point I do not believe I will be able to remove them. Right now live and let live, I just wish I could get to their honey.