The Zirdle Bug is a red-hot streamer/nymph combo “junk fly” in southwest Montana, particularly on lower-elevation rivers like the Beaverhead, lower Madison, Jefferson, and Missouri, where crayfish are present. It roughly matches crayfish, sculpins and other baitfish, and stonefly nymphs. Fish it in a variety of ways: swung or stripped like a streamer, dead-drifted under an indicator, or dragged on a tight line. This one is sort of a tan-copper-brown-orange color, but you can tie them in a wide range of natural and attractor colors. This one is merely intended to serve as an example.