One of the more common flies in our part of the world is the yellow dung fly, Scatophaga stercoraria. Despite it's name, this fly is not eating dung, but nectar. In spring, many of these flies can be found on early flowering Prunus spinosa and relatives. This is the place where the yellow dung fly mates, to ensure a next year with dung flies. The eggs are laid in cow dung, hence the name of this insect.
On the Prunus in our backyard, a dung fly was enjoying the sun this morning. A male, which is yellowish, where females are more green. I shot it with the Vivitar 55/2.8 + flash tube.