Well, in the first (and second) pic there isn't a bee but a hover fly (family Syrphidae).

The species should be Eristalis tenax (just check the pattern on its back).

You may learn more about the differences between flies (includig hover flies) and bees here.
For example bees (belonging to the order Hymenoptera) always have four wings, while flies belonging to the order Diptera) have only two wings plus halteres.