The Quill Gordons (Eperous Pleuralis) nymphs are clingers. For most of their life,up until it is near the time for them to hatch, they stay hidden down between and under the rocks on the bottom of the fast water runs and riffles. They are not readily available for trout to eat. A few days before they begin to hatch they move from their fast water habitat to slower moving water. Often this is behind large rocks and boulders near the fast water. Trout are very aware of this short migration of the nymphs and take advantage of them during this time when it is very easy for them to do so.
If they are not eaten by trout, the nymphs remain there until they are ready to hatch. Unlike most mayflies, the Quill Gordon's wings pop out of their wing pads and the shuck comes off the nymph on the bottom or somewhere between the bottom and the surface of the water. In other words, they hatch under water, not on the surface of the water.
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