For 2 years now, I've been sowing red runner beans on my balcony. I see frequently giant black bees on the red flowers. They do not seem interested in any other flowers (sunflowers excepted). I've "googled" for bees, but can't find a critter like "my bee" : more than 1 inch long, dark wings and body. The belly almost triangular. Last year I was lucky to see a giant moth (mistaking it for a hummingbird) and got some help from people on GW.

Agnes