Mason Bee Covered in Pollin

The easiest way to tell a bee apart from a fly is to look at the wings. Flies only have two wings, whereas a bee (any bee) has four wings. It can be difficult when the bee is really tiny, but if it is going in and out of flowers then there is a good chance that it is a bee. Most mason bees are smaller than a honey bee, which gives them an advantage. Mason bees can fit in a larger selection of flowers.

You can even try to follow them to their home. All bees fly as straight as they can back to their home. Known as a "bee line", they don't waste precious energy sightseeing.