Mystery bees in the yard

The second half of our package bee installation blog is coming later today, but in the meantime:

Does anyone recognize these two? I found them on a dead pine branch in the yard. They have pronouncedly triangular heads and long tapered bodies. I would have thought they were some other sort of insect, but there are gold and black stripes on their thoraxes (hard to see in my iPhone shot)–that made me think they were some sort of Apis.

Anyone have an idea?