.......................  ....................  ...Fly Fishing Yellowstone National Park
New KISS Bug Series - Part 44

Western Green Drake

The Western Green Drake bears zero resemblance to the Eastern Green Drake. They are completely
different insects. The Western Green Drakes are large but not near as large as the Eastern Green Drakes.
You could say that a Western Green Drake is a giant Blue-winged Olive mayfly. In fact, the Eastern
Blue-winged olives are actually in the same
Drunella genus.

The common name Western Green Drake name is give to two different species of the
Drunella genus, the
dodsi and the grandis. Both species are very similar. You could determine the species from looking closely
at the nymphs but not the duns. The nymphs vary some but the duns vary little. It would take a microscope
to determine the species of the dun. Neither the duns or the nymphs vary enough that you need a
separate fly pattern or method of imitating them.

Trout can be taken on all stages of the Western Green Drake's life but the dun is certainly the most
popular stage to imitate. The large mayfly floats on the surface a few seconds and brings about some very
good action on the dry fly.

Most of the streams in Yellowstone National Park have these mayflies. The hatch times vary greatly
depending on the elevation of the stream and the surrounding mountains. As a general rule, on the same
stream, the
grandis species hatches first and the dodsi species follows a few days later. This can vary from
stream to stream. In other words, the
dodsi species could hatch days before the grandis species hatches
on a different stream at a higher elevation. This is just for information. It shouldn't make any difference to
you which species is hatching as long as you know they are Western Green Drakes.

dodsi species also tends to be found in faster water than the grandis species. Most anglers don't think
of the Green Drake as being a Yellowstone National Park hatch. So much publicity regarding this mayfly
has been given to some of the nearby streams that are outside of the park that the Green Drake hatches
within the park seem unimportant to many visiting anglers. It's certainly true that some nearby, notably the
Henry's Fork of the Snake River, have excellent Western Green Drake hatches, but it's also a fact that
several of the streams within the park have excellent hatches. You can fish the hatches in the park for a
much longer period of time. Hatches take place in the Northeastern section of the park much later than
they do in the Northwestern section, for example. In the forthcoming articles, I will cover the fishing methods
for these large mayflies.
Copyright 2012 James Marsh
Western Green Drake
Availability to trout:             
Hook Size:                          
Type of water:                    
Emergence time:                
Duration of hatch period:

Drunella dodsi and grandis species
Most all moderate speed water streams
Western Green Drake Dun