... Charlie's statement in his description of the Chubby Chernobyl quoted below ...

"The Chubby Chernobyl comes from Idylwilde Flies out of Portland, Oregon. The Chubby is a take-off on the standard Chernobyl Ant, but with a much needed improvement; a big poly yarn wing that aids in flotation and visibility! You see, a standard Chernobyl is but thread and foam and floats well but low in the water. Not a big issue when being fished and spotted from the higher perspective of a drift boat, but toss that same fly while wade fishing and the low floating coupled with a lower sight angle and suddenly that inch and a half long fly becomes very hard to see and find! Damn near genius, someone at Idylwilde added a pair of thick, white poly yarn wings and not only made the fly WAY more visible (it looks like a marshmallow bobbing along out there) but drastically improved the floatation as well. Really a pretty simple fly to tie, the Chubby is a perfect dry dropper or HCD rig dry that will float a big tungsten nymph or two underneath it with no complaints. I'm not positive what exactly it imitates but it is certainly reminiscent of the ubiquitous Pickle, aka. Pat's Rubber Legs Nymph and perhaps the Chubby is what the Pickle hatches into upon maturity. None the less, the Chubby can cross over for a golden stone, a hopper or even that marshmallow if need be and will float all day long."

... how a material tied in above the point where the fly floats, that is on the top of the foam which is above the water surface, improves floatation ?? Seems to me the poly wing just adds weight and will reduce floatation.

No doubt that the poly wing improves visibility, for those who need that assist for whatever reason.

John