Double-Egg and Sperm
Weight the hook so the fly will travel near the bottom. This fly resembles drifting roe from spawning fish. The white wing mimics milt that has covered the eggs.
Pink is another useful color.
How to Fish
Traditional wet-fly swing or use with an indicator and dead-drift the fly near the river bottom. If you see spawning fish, cast the fly so it will sink to the bottom downstream from the happy couple. Undoubtably some other fish will be there waiting to scarf up the drifting roe.