Male Nixe inconspicua Mayfly Dun Pictures

Dun: Mayflies have two adult stages. They first emerge from the water as duns (scientifically known as the subimago stage). They then molt into the spinner (imago) stage, in which they mate and die. Sometimes the word "dun" is confusingly used to refer to a brownish gray color in fly tying materials.

Tarsus: The often multi-segmented outer leg section of an insect, which attached to the tibia.