Gray Drakes
.............................Fly Fishing Yellowstone National Park

Gray Drakes (Black Drakes) - (Siphlonurus species)

The Gray Drake, also called the Black Drake, exist in several of the streams in
Yellowstone National Park. These are species of the
Siphlonurus genus of the
Siphlonuridae family of mayflies. They are important to anglers in the nymph and
spinner stages of life. These mayflies are found rivers with slower moving water that
usually has aquatic vegetation. Because of this, the nymphs and duns vary
considerably in color depending upon the bottom composition and aquatic vegetation
in the water in which they are found in. We found a large concentration of these
mayflies in the Snake River just above the point it exits the park boundary but they
exist in many other streams.
We categorized the
alternatus, occidententalis, columbianus, and the spectabilis
species together, as they are almost identical. I am not positive at this time which
species exist in the park but this should make no difference in the manner in which you
imitate these mayflies.
They are different from most species of mayflies in that the nymphs crawl out of the
water to hatch. It is not necessary to imitate the dun. It would get into the water only by
accident. The spinners are very important. We will cover the details of fishing the
nymphs and spinner fall stages of life in the next two articles.

Coming Up Next:
Gray Drake - (Siphlonurus species) - Nymphs

Copyright 2008 James Marsh
Rare picture of a Gray Drake Dun on your left