Finally, A Bee

and of course, I had to wonder, is it a fly? Lately it seems everytime I look at something dipping into a flower, it turns out to be a fly. I'm trying to figure out what type of native pollinating bee is pictured above. Right now, I think it's a Leafcutter, possibly in the genus Megachile. I did see some very neatly chewed holes nearby. Perhaps a cozy nest has been built on a rooftop in Manhattan.