The female isonychia is often a shade of brighter colored olive when first hatch. It will then darken up into the more well known colors of the iso. With this little piece of knowledge comes more takes, because if females are hatching, your gonna be pressed to be putting up numbers with a rusty or mahogany dun. Tossing this fly around has brought me some great luck when I see a slate drake emerge.
Hook- Daiichi 1180 #12
Thread- Olive 8/0
Tail- chartreuse dyed grizzly hackle fibers
Body- Pale evening dun and brown dry fly dubbin blended
Post- 4 dun cdc feathers
Hackle- MP cdc dirty yellow.