Look at the calendar. If it says May at the top, an angler should be ready to match a green drake hatch at any moment. It’s a short window of opportunity, but it’s the most important thing happening that week in the eyes of Drunella grandis and Oncorhynchus mykiss gairdneri (the redband rainbow).

The green drake is a sporadic hatch on most Western streams, but it can be abundant on the Metolius and a few others. It is a good idea to carry dries to match this mayfly when the adults could show up any time. This Loop Wing Green Drake is a faithful fun-to-tie imitation.

Tie this pattern with olive thread on a No. 10 dry fly hook. For the tail, use olive hackle fibers, split with a thread lift. Build the body with olive dubbing. The loop wings are formed with variegated olive hackle trimmed tight. Finish with a standard dry-fly hackle collar.

—Gary Lewis, for The Bulletin