right on the money MKern , that shellback combined with the ribbing and dubbing creates that segmented buggy look and the dubbing looks like the row of gills that run down the sides of the naturals , even better if the dubbing "breathes a little" those little things that make our flies look natural to the fish. I read an article once that talked about the fish needing a certain amount of things to look right in order to take , it was like three things match up and it's a hit , was like color , size , movement or something like that.