This is spinner stage of the Speckled Wing Quill. It imitates the insect when it fully develops and returns to the water to mate, deposit eggs, if the female, and both male and female fall dead spent on the water.. The Speckled Winged Quills are often called "Callibaetis", which is the scientific name of the genus these mayflies belong too. They are found in slow moving water of streams and still water of lakes and ponds. Trout eat them in all stages of their life. A must for still water anglers.