The story of Mike’s Midge Pupa began during a visit to a well-known Pennsylvania spring creek. I was working my way through a meadow, trying not to spook any trout, when I noticed a disturbance on the water. I stopped, crouched down, and saw a nice rainbow take an insect on, or near, the surface.
Once I got closer, I knelt down behind a clump of grass and watched the fish for several minutes. It was pushing water with its nose to take its meal, leaving me to believe that it was feeding just under the surface. And because of the absence of any hatching mayflies or caddis, I concluded that the rainbow was eating midge pupae.
I tied on a small Brassie and made a perfect cast. The fly landed right on the mark, one foot upstream in the fish’s feeding lane. The rainbow, however, didn’t like what it saw and continued to feed in the drift. Then I tried a gray-bodied pupa, and then a another fly, but nothing. Not even a look.
For the next half-hour, I watched the rainbow take pupa after pupa. Finally, when I couldn’t take any more, I carefully backed away from the water and headed back to my truck. For the entire walk, I thought about how to get that fish.
Imitating the Natural
Since that day onstream, I’ve learned a lot about midges. Most important, I’ve learned that a midge pupa rides vertically in the surface film.
During an experiment at home, I noticed that none of the pupa patterns in my fly box sat vertically when in water. A Brassie, for example, descended horizontally when dropped into a glass of water. No good; at least not for that fussy spring-creek rainbow that sent me home humbled and frustrated.
So, when I sat down to create a more accurate midge pupa imitation, my goals were to 1) create an abdomen that would hang vertically in the surface film and 2) a thorax (and gills) that would provide floatation and hold it there. How I came about the materials for each part follows.
The Abdomen. After experimenting with several materials, I chose goose biots for the abdomen. When wrapped, they give the fly a slender, segmented look similar to the natural. The goose biots also make the back of the fly less buoyant, enabling the hook to pierce the surface and suspend vertically. I prefer olive biots throughout the season, though I’ve seen midges in shades of black, gray, and white.
The Thorax. The thorax on a midge pupa is tiny; but it’s worth noting. After my experience with that rainbow, do you think I would leave anything out? No way.
I looked for a buoyant material that would take up a tiny space on the hook. A piece of open-cell foam cut very thin was the answer. I found a sheet of black Larva-Lace Fly Tying Foam and cut it 1/16-inch thick. Two overlapping turns of the foam provides a small thorax that floats.
The Gills. The gill material needed to assist the fly’s buoyancy as well as mimic the gentle movements of a midge’s respiratory horns or gills. The gills are the only part of the pattern with movement and I didn’t want to miss this paramount aspect.
I first tried a turn of hackle, but it didn’t give me the impression of the free-moving gills suspended in the water’s surface. Then I tied in a piece of white Cul de Canard (CDC) and found the action I wanted. I use white CDC for easier visibility, but I also use dun CDC to better imitate the natural.
When I dropped the finished fly in a glass of water, it suspended vertically in the surface film, just like the natural. I couldn’t wait to see that rainbow’s reaction.
Fishing Mike’s Midge Pupa
The most effective way to present this pattern to a feeding trout is with a dead-drift. While the fly floats naturally with the current, the CDC gills move in the stream’s gentle turbulence and give the fly a lifelike action.
Find a casting position that allows you to false-cast without spooking the fish. Usually behind the trout is a good spot because from there you can stay out of the trout’s view and get into the same current lane as the trout.
Place the midge pupa from 6 to 12 inches above the rising trout and let the fly drift over its nose. I use 32 inches of 6X tippet when fishing the midge pupa; but overfished, finicky spring-creek trout often require 36 inches of 7X tippet.
By the way, that finicky spring-creek rainbow that led me to create Mike’s Midge Pupa measured 163/4 inches. Although it’s not the largest trout I have caught and released, it is one I’ll never forget.
Michael Heck grew up on the spring creeks of central Pennsylvania. He lives in Chambersburg, Pennsylvania and guides on the Falling Spring Branch and other area waters.