Welcome to Not Quite Entomology

Welcome to Not Quite Entomology! This is a different approach to matching the hatch, or learning which insect the fish are really eating. The flies and methods to make it all work will be here as well. We hope this series will inspire you to go out, look on top of and under rocks, check the stream-side vegetation, really investigate your favorite water and learn which are your local trout's favorite foods!

The Stones

By Ladyfisher

Old Rupe is "off his feet" for a while, and we will fill in for him the best we can. If you are knowledgeable about a particular insect or local hatch, please help us out - contact: LadyFisher. Don't worry about photos, we have good references.

Stonefly nymph

Stoneflies are the creepiest crawlers of the trout world. Well suited for some horror movie on Stonezilla Engulfs the World! They really are members of the order Plecoptera but their common name of Stoneflies probably came from where they are found along streams hiding or crawling in the rocks and stones. They are closely related to cockroaches, indeed very primitive.

The lavae is well matched by the Montana Nymph. Tie them to match, size and color, whatever stones are in your region at various times of the year. This is an important fly.

Adult Stonefly Adult stone flies have four wings, which are heavily veined. The wings lie flat over the back, except when they fly. Auto accidents have been caused on blacktop highways caused by misguided Stone Flies. They mistake the blacktop for water and land in such numbers as to make the road slippery.

Most of the stoneflies are restricted to highly oxygenated waters, and are considered an indicator of the water quality. These are freshwater insects, with around 500 known North American species, ranging in size from very small to the giant stones like the Salmonfly. While rivers are the most likely home to salmonflies, some lakes, especially those with wave action, like Lake Tahoe, have large populations.


Stoneflies are very important food sources for game fishes, and some even emerge in winter. All stoneflies are fish food in the larvael stage as well. In fact, the first recorded artificial fly - made over four hundred and fifty years ago - was based on a British stonefly.

The governing factors for emergence of stones is water temperature, altitude and latitude. The larvae climbs out of the water onto streamside rocks and bushes or structure of some sort, and then once their wings are dried, fly over the water to deposit their eggs. Some dip onto the water surface, and other adults crawl back into the water from whence they came. The males sometimes emerge before the females, and the males of some species actually attract females by beating their abdomen against a hard surface. A responsive female will return the signal.

Molting Salmonfly, note color! Stoneflies unlike the mayfly, live as adults from a few days to about five weeks! The emergence usually starts at the higher altitudes of a stream and continues downstream as the correct conditions occur. Fishermen get a really great shot at this hatch!

Another favorite of fishermen because it is an early Western spring hatch, March in some places, is the Gray Stone (called the Nasqually or Squalla in some regions). Other 'stones' vary in color from the salmon pink to tan and dark brown.

Knowledgeable fly fishers on rivers like the Madison and Yellowstone in Montana fish the giant stonefly Pteronarcyidae 'hatch' from it's beginnings to the end downstream, and may have a couple of weeks of excellent fishing with the size 2 Salmonfly.

Some of the other well-known stonefly patterns include the Golden Stone (also one of the 'giants'), Yellow Sally (size 12 - 16), Sofa Pillow, Bird's Stonefly, and Artesan Green. Both Woolly Worms for the nymph, or Elk Hair Caddis tied dark in sizes 14 - 18 are excellent for the little Black Stone.

How the fish sees a stonefly

For the panfishers, Smallmouth Bass also eat stoneflies.

Emerged and egg laying stoneflies ride in the water, they don't float on top of the water, as do mayflies and caddis. Keep this in mind as you tie or buy flies to imitate your locals.

The emergence of the adult stonefly falls into the minor miracle catagory, for a complete photo history of it check out this Ladyfisher article. Check for empty shucks Stoneflies, both the nymph and the adult are under fished in many regions simply because they don't hatch as mayflies and caddis do, making a visible entry into the fisherman's world. Check the waters edge for empty shucks and watch for the egg-laying! The fish love 'em and you will too! ~ LadyFisher

For more on stoneflies check these out:

Photo credits: Stonefly nymph drawings from Aquatic Entomology by W. Patrick McCafferty, published by Jones and Bartlett, remaining photos by James Birkholm.

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