I tied one of Gary Borger's "Yarn Wing Duns" in a post recently.
Last night, I was reading his book "Fishing the Film" (2012). In it, he mentions that he has modified his original version.

The biggest modification is that he bends the front of the shank upward, about 1/3 of the way back from the eye. This: 1. Causes the wing to position better; 2. Rides more like a natural.

The other feature about this pattern is that he uses the "X" style hackling to be more like the natural's legs.....


Anyway, I used Zelon which does't trim as neatly as yarn, but I like the glistening effect and I did not bend the hook in quite as severe an upward angle as Borger suggests.

Some pictures of the insect on the water.