tactics

Cinygmula Mayflies

By Jeff Morgan

One of the most overlooked mayflies in the West, Cinygmulas (red quills) are common in many small creeks--and a few big rivers.

Images

(See the entomology page for photos)

inygmula mayflies are so ignored by fly anglers that it is difficult to find anyone who has heard of them by either their scientific name or their uncommon common name, red quill.

However, eight of the nine Cinygmula and all four species of Cinygma are found in the West. Cinygmula and Cinygma predominate in the small, higher elevation streams of the Cascade Mountains and are almost always the most populous mayfly there. These insects are also present in other small, cold streams throughout the West.

The diversity of these clinger-type mayflies is amazing. In a study by J.V. Ward, they were the only insect inhabiting all elevations (3400 to 1800 meters) of St. Vrain Creek in Colorado.

Their populations are much smaller on the larger "glamour" waters, however, and for this reason we rarely hear or read about them. Some anglers may argue that the trout in small mountain streams--the waters most likely to host these insects--are rarely selective, so there is no need to imitate specific genera. However, understanding these insects will prove very useful on small streams, which are the West's most under-utilized fishing resource.

Nymphs

Cinygmula nymphs are medium-small (7-11 millimeters) in size, and come in shades of brown. Their coloration could be due to their affinity for small streams, which have large amounts of leaves and wood in them. They like swift water, and are well suited for it.

Like other mayfly clingers, they have a flattened shape, and the head is unusually large relative to the size of the body. This head shape lets them face into the current, and the water flows around the body like a teardrop. Though flattened like all clingers, they often are found in the slowest parts of fast water: under rocks and in crevices between boulders.

Cinygma may be the only mayfly nymph that feeds on wood; other mayfly nymphs will feed on the algae that grows on wood, but don't consume the wood itself. Thus, this is an important insect in headwater streams, where wood content is the greatest.

Cinygmula nymphs are more susceptible to dislodging following spate conditions than other clingers. Larger Cinygmula nymphs tend to follow a nightly drift pattern (like many other aquatic insects), though they drift best on moonless nights. Cinygmula will also drift when the sediment load of the river suddenly increases, so they are a good nymph to imitate at the start of spate flooding.

With all this drifting, it is no surprise that these nymphs are often eaten by trout. Several stomach pumpings I have done on trout in the Oregon Cascades confirmed this.

A dark Hares Ear is usually sufficient to imitate Cinygmula nymphs, though some of us like to tie more imitative patterns, like Oliver Edwards' Heptageniid Nymph. Fish these flies with weight under a strike indicator in swift water.

I usually use a Cinygmula nymph in conjunction with imitations of other swiftwater insects like Epeorus, blue-winged olives, Perlid stoneflies, and green caddis. It is crucial to keep a team of these imitations near the bottom. You may be able to fool fish in slower water without getting right on the bottom, but swiftwater trout will rarely be so forgiving.

Imitating rising nymph of this insect is rarely effective, because trout seem to ignore small foods drifting in the middle of the turbulent water column

Emergers and Adults

There is little to no literature about the exact life cycle of Cinygmula and Cinygma. We don't really know how they emerge, but I have never seen fish feeding selectively on emergers.

The adult emergence peaks in the early summer--May and June--and the adults are brownish-olive in color. Since hatches of Cinygmula are almost always sparse, and occur over a several-month period, trout are used to seeing them and are rarely selective to them. Hafele and Hughes mention that the adults almost perfectly match those of Heptegenia (the pale evening dun), and I agree.

Because Cinymula adults seldom come off in dense numbers, and because hatches are usually in fast water, you rarely need an exact imitation. Many anglers simply use an Adams, Parachute Adams, or a Light Cahill to imitate the dun stage of this insect. Other anglers use pale morning dun or pale evening dun imitations for this hatch, and that can work too. Just make sure your imitation is durable and a good floater.

We don't know how long these insects live or their egg-laying habits. No one has documented a spinner fall, and considering the water these mayflies inhabit, the spinners are probably not important to trout.

Jeff Morgan has written many articles for Westfly, mostly on entomology and fly tying. He is the author of An Angler's Guide to the Oregon Cascades and Small Stream Fly Fishing. Jeff is currently a graduate student at Stanford University, where he is finishing his PhD in History.

Uploaded 02/26/2001.

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