Deer flies,
As you know, they really like to fly around your head, looking for that bit of exposed skin to land on. Here's a trick that really works:
When Mr. Deer Fly is circling your head, place your hand on top of your head, palm down. The deer fly will land on your hand, he can't help himself! Smack 'em with your other hand, step on him, pick him up, dig a big hole, place the deer fly in the hole and cover with cement. This should give you enough time to get away from him before he emerges from the hole, slightly irritated!
HH