Several of these bumble bee mimic flies were on some late-blooming goldenrod, along with a myriad of other insects, all trying to find that last bit of food before the frost. I think is probably Eristalis flavipes. At first glance, these flies look like bumble bees. They have the same colouring, habits and they buzzzzz as they fly by! But, if you look closely, you'll see the eyes are quite different, the antennae are short, and they have two, not four wings. However, the latter is not always readily discernible, as bees often hold their four wings such that they look two-winged.