CdC and Z-Lon BWO Emerger

The Ephemerella Aurivilli hatch is one of the highlights of the Norwegian fly fishing season. The Cdc and Z-Lon Emerger is an attempt to use few materials to create an efficient flymph like emerger pattern for this interesting may may fly.


The Aurivilli is one of the most interesting species in Norwegian running water. Being a fairly large insect it attracts the big guys to the surface. Since the Aurivilli often needs a long time to break through the nymph shell and the surface tension, trout love feeding on emergers.

This pattern tries to imitate the emergent position of the Aurivilli nymph. It usually hatch horizontal in the water, with the nymph suck creating the illusion of a larger insect. Therefore, I have used the CdC bubble technique, combined with a moderately curved hook (here the TMC 200R). This is really a flymph variant, not the modern day vertical emerger.

On this pattern I tie the shuck and the abdomen in one operation. Mixing a few strands of Golden Olive and Brown Z-Lon I first tie in the shuck and then proceed with the Z-Lon towards the eye to create a nicely segmented body. This fly really stands out from the crowd in the river – the sparkle of Z-Lon makes sure of that.

I have not tested this specific pattern before, but I do expect that it will do well this season. If you try it, please give me feedback on the efficiency of the pattern.

The CdC and Z-Lon emerger can easily be adapted to other BWOs.

The color of the Aurivilli varies from golden olive to yellowish olive. You really need to take a look at your local water before matching the color perfectly. But on a dun you will not go very wrong if you have two variants in your box: the Golden Olive (FlyRite #8) and a mix of FlyRite #15 and FlyRite #9 (60/40).

I usually tie the emerger golden olive and brown.


Hook: TMC 200R – Size 14
Thread: Sheer 14/0 Orange
Shuck: Mix of Golden Olive and Brown Z-Lon.
Abdomen:  Same as Shuck
Wing: Two fairly dense CdC feathers, natural brown
Thorax: Golden Olive and Brown dubbing mix – brushed out to suggest legs

Materials are listed in order of tying.

Read more about the TMC 200R here

Fishing Tips

High and dry  – dead drift as most other dry duns.