Great Red Spinners

This is by far the most important species of Isonychia. Many angling books once split its credit with the species Isonychia sadleri and Isonychia harperi, but entomologists have since discovered that those are just variations of this abundant species.

See the main Isonychia page for more about these intriguing mayflies.

This species, together with Drunella doddsii, creates the beloved Western Green Drake hatches, the Rocky Mountains' answer to the popular Ephemeridae drakes of the East.

I have not fished out West to experience this hatch, so this page relies on information collected from angling authors. Unfortunately these books conflict with each other on several points. I encourage readers who've fished this hatch to share their experiences in the comments and help clarify the information.

Timpanoga hecuba is not abundant enough, and its emergence not concentrated enough, to provide great hatches, but where it is locally abundant it creates fishable action because of its large size. It is one of the largest species in the Ephemerellidae family, being almost the size of Drunella grandis, the Western Green Drake.

In the East and Midwest this is one of the most important hatches of the Spring. They are large flies which emerge sporadically, making for long days of good fishing.

This species contains the two classic Eastern hatches formerly known as Stenonema vicarium and Stenonema fuscom, the "March Brown" and "Gray Fox." Entomologists have discovered that these mayflies belong to the same species, but they still display differences in appearance which the trout notice easily. Anglers should be prepared to imitate both types.

This secondary species creates the Western Green Drake hatch together with Drunella grandis. There are very few differences between the habits of these two species, and they are almost always discussed together in fly fishing books, so for most of the characteristics of doddsii I refer you to the Drunella grandis page.

The Brown Drakes are a favorite hatch of many in the Midwest, and they make a good showing on localized waters across the country. They are usually the first in a series of big drakes which bring large trout to the surface at twilight and into the early hours of the night.