The following is an excerpt reproduced with written permission from Globe Pequot Press; from the book, “Selective Trout” written by Carl Richards and Doug Swisher; illustrated by Dave Whitlock; ©1971, 2001; 272 pages, 8 1/2″ x 10 3/4″; which can be purchased at fine fly shops and booksellers everywhere.
Patterns Evolved: Nymphs
One of the most essential yet seemingly simple aspects of creating a deadly pattern is size. This is especially true for the smaller flies, those less than 7 or 8 mm in length. If, for example, we are trying to imitate a natural that is 5 mm long and our artificial ends up being 6 mm long, we are a whopping 20 percent too large. One millimeter does not sound like much, but it can mean the difference between success and failure, particularly when diminutive patterns are used. The best procedure is to measure the natural accurately and then tie the artificial on a hook bearing a shank of the proper length. At streamside, it is helpful to use a small hand magnifier to obtain an accurate comparison of artificial to natural. This identification part of our study requires precise measurement of each specimen, and this information is then put to use in the tying process. It is far better to use actual measurements than hook size when describing patterns. Hook specifications differ greatly and are therefore unreliable for our purpose, other than as a general denotation of size.
Another factor that affected the development of new patterns was the action, or lack of action, of each species both in, on, and above the water. Most of this information was gained through observations made at streamside or at the aquarium. The majority of in-water activity was observed in the home aquariums, where nymphal life could easily be inspected on a day-to-day basis. Watching the nymphs move about and emerge into adults provided valuable knowledge for designing new subsurface and in-the-film patterns. Streamside observations offered us criteria for new adult dressings and corresponding techniques for their effective application.
Probably the most basic requirement of a nymphal pattern is that some type of dubbing should be used for the body. Other materials such as quills, floss, wool, thread, and plastics may look enticing on the vise, but they take on a distinctly unnatural appearance when they are wet. Our nymphs have bodies constructed from such furs as rabbit, muskrat, opossum, fox, mole, and beaver. Fine-textured furs or dubbing should be utilized for small flies, size #20 and smaller—not only for appearance but also for ease of spinning. White domestic rabbit (or synthetic) is an excellent dubbing material because it can be readily dyed to the proper color and it is usually fine grained. Tails from wild rabbits have the added advantage of providing many light-to-dark shades when dyed a certain color. Legs and tails are normally best imitated with such feathers as wood duck, mallard, or partridge tinted to the proper shade. Some of the better wing case materials include ostrich herl, quill segments, breast feathers, fur, and foam.
Here is our recommended procedure for tying an extended-body wiggle nymph.
1. Make a loop from a thin strand of piano wire in the length you require for the abdomen of the nymph.
2. Put the loop in a fly-tying vise and tie on the tails and fur so that just the loop sticks out from the body.
3. Make another loop of piano wire and insert it in the first loop. The abdomen is then tied on through the second loop to form a hinge. Then tie the second hinge on top of a 5X short-shank hook.
4. Tie the thorax, wing cases, and hackle on the hook part of the nymph and finish as usual.
Our observation of nymphs swimming about in the aquarium revealed possibilities for several different patterns. We noticed that all species swim with a distinct undulating movement of the abdomen. Attempts to imitate this situation resulted in extended-body and “wiggle” nymphs.
The extended-body nymph has the abdomen tied on a piece of wire or hook that can be bent in any direction. This makes the nymph look more realistic and is simple to tie. The wiggle nymph, however, carries the idea a step farther by adding a hinge between the thorax and abdomen. This allows the rear part of the fly to move freely, and it more closely simulates the movement of the real nymph. The wiggle nymph is somewhat more difficult to tie but it can be mastered with a little practice. Many methods can be used, but probably the best one involves very fine wire or monofilament for the hinge. Use a short-shank hook for the thorax and leave a small loop of wire extended from the bend. Loop another piece of wire through the first loop and then construct the abdomen and tails on the doubled-back piece.
An easier method is to tie the back part of the fly on a small hook first, and then cut off the bend. Attach this part (the abdomen) to the thorax with a fine wire or monofilament loop. We have also used rubber bands and plain tying thread for the hinge. As for the legs, let most of the fibers extend backward conventionally, but a tie a few of them forward. Sometimes stiffer materials, such as deer or porcupine, are necessary for the front legs. These extended-body and wiggle nymphs have proven themselves to be very effective, not only in matching the hatch, but also when used as attractors.
The most important nymphal pattern may be the floating nymph. Our extensive use of the stomach pump over the past 25 years has shown that a huge part of the trout’s diet consists of nymphs that are drifting in or on the surface film. These are very difficult for the angler to see because of their typically dark coloration and low profile. The fish, however, have the advantage of backlighting and can pick them off with ease. We tie these patterns on light-wire hooks and use materials that promote good flotation. For the all-important wing case, spin a large ball of dubbing or use one of the commonly available foam materials. These flies are more difficult to see than a high-floating dun, but they are quite often the key to fooling a selective riser.