I was up on a small stream today, and there was a large black fly that the was on the water periodically, and one had 3 fish after it before the 3 one got it.
it had a very distinct head, a abdomen that was longer, and a tail section that was even longer (all black), and a clear wing case with six legs.
I have seen a picture of this fly before, and a a dry fly variation. however I am unable to find it now.