Although many nymph patterns today are intended to imitate a much greater spectrum of aquatic foods, rather than the nymphal stage of one specific, this pattern imitates the final nymphal stage of the largest burrowing mayflies Ephemera guttulata (Green Drake) and Ephemera simulans (Brown Drake) and the European relatives Ephemera danica and vulgate.. These nymphs prefer soft organic or sandy and muddy bottoms, where they can live more or less buried for up to several years, only appearing occasionally to feed on decomposing vegetable and plant matter. They have been known to burrow as deep as fifty feet. These large nymphs that range from 12-32 mm in length, can be easily recognised by the breathing gills along the sides of the rear body, and over sized fore legs that are adapted for burrowing. The gills however are not only used for breathing but also function as a ventilation system for the tunnel they burrow keeping water flowing through it, which in turn keeps it open. If the nymph leaves its burrow or stops the undulating movement of the gills, the burrow collapses shortly afterwards. These nymphs, are for most of their life, unavailable for the trout, but one of these on your leader at the correct time can make the difference between great sport and no sport. When the time is right and they leave the safety of their burrows, swimming quickly with an undulating body movement, (something that ostrich herl and CdC imitate beautifully) towards the surface, trout can feed on this ascending nymphal stage for several hours before turning on to the subimago winged stage. The weight that is placed under the thorax of the nymph helps emulate this undulating swimming action when pulled through the water with short pauses.
When it comes to tying these large nymphs your hook choice should reflect the natural body length, so a 3XL or a 4XL hook in a size 8-12 works well. The dubbing used for the rear body and the thorax should be one that absorbs water and not a water repellant dry fly dubbing. Another trick that helps to get the nymph down is after you have tied it on your leader give it a few seconds in the water and then squeeze it hard between your finger and thumb to press out any trapped air that may be caught in the dubbing and CdC. I also like to use a UV treated dubbing and Ostrich herl. Although I have not had the same marked results that show trout prefer the UV patterns in fresh water, unlike the results I have had in salt water, it does no harm in giving the pattern that extra edge that may make a difference. Previously I have used golden pheasant centre tail fibres for the wing case but these have proved to be a little too fragile for the small sharp teeth of trout, so I have substituted it with Antron body wool.
Burrowing Mayfly Nymph pattern
Hook Mustad R73 9671 # 8-12
Tying thread Dyneema
Tail Olive ostrich herl
Body Olive brown Antron dubbing
Rib Olive Ostrich herl
Thorax Olive brown Antron dubbing
Wing case Floss or Antron body wool
Legs Olive CdC
Secure your 3 XL or 4XL nymph hook in the vice making sure that its horizontal.
Attach your tying thread and cover the whole shank until the thread is hanging between the hook barb and point.
When it comes to weighting flies I like to use a lead free alternative.
Wind on a short length of lead free wire under the thorax, covering approximately one third of the hook shank.
Once the lead free wire is wound and packed tight trim off the surplus.
For the tails of the nymph you will need some olive ostrich herl, here I like to use a UV treated herl to the the nymph an extra edge.
Select three herl’s with even tips. Tie inn the first herl on top centre of the hook shank. Again this should be about one third of the hook shanks length.
Now tie in the other two herl’s one each side of the centre tail.
Tie down the remaining herl along the whole hook shank and cut away the excess herl.
Now select another long herl with nice long fibres for the ribbing that will represent the nymphs gills.
Now spin some Antron dubbing tightly onto the tying thread. Make sure that this is tight so the finished body is dense.
Continue with the Antron dubbing and build up a tapered rear body along 2/3 of the hook shank.
Wind on the ostrich herl as a rib over the rear body part, making sure that the herl fibres stand out at 90 degrees from the hook shank. About 6-7 tight even turns, and tie off at the thorax.
Remove the excess herl and carefully trim off the herl fibres, only on top of the body as shown. This is not necessary but gives a little more realistic look to the nymph.
The trimmed rear body should now look like this from the side.
And like this from above with the gills prominent along each side of the body.
Now cut four lengths of floss or Antron body wool and tie these is as shown along the the top of the thorax these will form the wing case later.
Trim off the ends of the floss behind the hook eye and tie down. Wind the tying thread back towards the rear body.
Dub the whole thorax quite heavily and return the tying thread once again to the junction between the thorax and the rear body. Take care that you leave about 2-3 mm space behind the hook eye to tie off the wing case later.
Now spin the CdC with the longest fibres at the top of the dubbing loop, these are to be wound in the thorax first for the longest legs.
Wind on the CdC dubbing brush in open even turns through the thorax to form the leg hackle.
Taking hold off all four pieces of floss, fold them over the thorax and secure with a couple of turns of tying thread. Once the floss is correctly placed pull once again to tighten up the wing case and secure properly with a few more turns of tying thread.
Whip finish and remove the tying thread. Finish off with a drop of varnish.
The finished olive mayfly nymph.
The finished brown mayfly nymph.
The finished grey mayfly nymph.