We have these hyssops that attract bees every summer - a wonderful sight. However, I have notice the bees this year to be much larger than usual.
Having heard about Africanized bees being aggressive, for example, stirred up my curiosity.
My bet is that they are Melissodes trinodes.
I don't believe that this is Melissodes trinodes; it looks more like Bombus impatiens to me - https://s-media-cache-ak0.pinimg.com/564x/c9/5b/18/c95b18c98a9d695c28c0336b0632d3e6.jpg
