Detailed instructions for tying a RS2 fly. The RS2 pattern was developed more than 30 years ago by Colorado angler and tier Rim Chung. The name of the fly is short for "Rim's Semblance 2," and it fishes well as both a midge or a mayfly emerger. The original version featured natural beaver fur dubbing and saddle hackle for the wing. Many more modern versions, such as the one shown here, feature different materials, while maintaining the profile of Chung's pattern. As with many great patterns that have stood the test of time, you can fish the RS2 in many different ways--on the surface, in the film, subsurface, or as a dropper off another emerger pattern. Colorado angler Ferenc Horvath maintains a website devoted to the RS2, which contains lots of great information, as well as a chart of good color combinations. This video, by Tim Flagler of Tightline Productions, offers step-by-step directions for tying this pattern by Matt Grobert. An author and blogger, Grobert shows off several neat tricks, such as using a short piece of extra thread to splay the tails, that will help you tie other small flies. The RS2: Hook: Straight-eye dry fly hook (here a Dai-Riki #310), size 18-24. Thread: Olive, 6/0 or 140 denier. Tails: Two white or dun Microfibbets. Abdomen: Light olive Superfine Dubbing. Wing: CDC, white or gray. Thorax: Light olive Superfine Dubbing.