Let them land and as soon as they put their head down, they can be swatted with ease. They wait a second or two between putting there head down and biting so you have to be patient or they will fly away if you try to swat them as soon as they land. Good luck.
Good advice. I've become quite good at hunting them before they are hunting me. One thing I noticed this past week while riding dirt roads on a golf cart in Georgia, they chase the cart, not the people. As soon as it is stopped, if you don't move your body around too much, they go away. The more aggressive you are, swatting, flailing at them, the more aggressive they become. Stop moving, let them land and then go for the kill. They will chase you if you continue walking because they're attracted to the movement, so just stop a minute.
As soon as i know i've been bitten, I apply alcohol and then spray with windex. This seems to help prevent the future itching.