We live just outside of Boston with a small backyard, a few old trees - definitely not woods. We had approximately 20 black flies that circled one area of the yard constantly throughout the summer. They have started early this year because of our warm weather. I've search the web to see if I can figure out what they are with no luck. Our neighbors have them too. They circle over the grass and also where the deck and the grass meet. Sometimes we get additional batches in other areas of the lawn but they just seem to stick to one spot. Any ideas of what they are and how to get rid of them? Any input is greatly appreciated. They are driving us crazy!