May Fly MS10. These flies are slim and elegant. The mature nymphs have a very distinctive wriggling motion. They make very tempting targets for hungry trout as they migrate in large numbers to above water objects.
Trout gorge themselves on the migrating nymphs and they can provoke a feeding frenzy.
It hatches a lot later in the year than the other upwinged duns and spinners. The adult damselfly comes in a number of colors but the most common is the blue. At times of mating they fly very low over the water surface and are grabbed by the fish. During mating the coupled flies land on any convenient emergent vegetation, down which the female walks to lay her eggs underwater. They belong to the Zygoptera group of insects.