This is a Zing Wing Caddis tied by John Betts. For a while, this fly was extremely popular. Betts says that for a whole year he fished nothing but this one fly and did very well. I believe it is so named, because, as the fly shoots past you on the forward cast, you hear the "zing" sound the plastic material for the wings makes. I have had good luck with the fly.
This one tied by John Betts himself.