Here are two versions of Morgan’s Chironomid Emerger. I can see that this pattern could be modified to replicate a BWO as well.  The fly is also tied with foam post/parachute style but the  CDC and the flashy shuck are a constant in the original pattern.  I posted this fly because I receive numerous queries for this pattern, so it must be important or in a magazine or site somewhere.  Not sure of the origins but upon research I see past articles out of the Dakota’s.