There are, by far, more dry mayfly patterns than any other dry fly. Let s have a look at the lifecycle of the mayfly and at the imitations created to resemble them. The mayflies undergo incomplete metamorphosis. They have no pupal stage.
Mayflies start out as eggs in the mud of the river or lake, regardless of the species.
The eggs hatch out into larva that we, the fly-fishers, call nymphs. These nymphs are quite tiny at first, but grow over the winter and progress through what is called larval instars. These instars are simply progressively larger stages of the nymph. The larvae are similar to an ant, where the little creature wears its skeleton on the outside of its body, like a suit of armour. This is called an exoskeleton.