A dry Inchworm Fly is an exceptionally versatile trout fly. In addition to catching trout that apparently take it for the natural inchworms, I catch many trout on it when there are very few natural inchworms close to the streams.
Frequently, the natural inchworms fall onto the stream with a pronounced splash. One way to achieve this with your presentation is to use a roll cast delivery in which you apply an extra snap of the wrist at the last second. Another effective delivery to achieve this controlled splash-presentation is to use a standard overhead cast and just as the fly is turning over on the forward cast, snap the rod tip down as if you were driving in a nail.
We discovered an unusual inchworm presentation by accident one summer on a small Pennsylvania stream. William Downey and I had pretty well finished fishing for the day and William was 100 feet upstream on the far side of the Creek watching me fish my last pool. He stood behind the fence on the side of the stream and allowed his fly rod to stick out over the edge of the stream. He had a dry inchworm on his leader which was just long enough to reach from his rod tip down to the surface of the stream. The current pulled his inchworm downstream a foot and as the leader tightened, the fly bounced up and down onto the surface of the stream. Several seconds later, a large brown trout came from beneath the undercut bank at William’s feet and took his fly. After landing this brown trout, William fished his way downstream along the undercut bank and caught two more large browns using this same technique. I often fish my Murray’s Dry Inchworm size 14 as a searching fly on Mountain Trout Streams throughout the season when there is no specific hatch of aquatic insects. The trout on feeding stations in the lip of the pools and along the runs on the sides of the riffle at the heads of the pools will often take the inchworm quickly.