Fly fishing nymph 2
When fly fishing with nymphs, presentation technique is important because of the varied nature of this sub-aquatic insect’s behavior. Originally the nymph was thought to be the logical extension of the wet fly, but time and experience have proven that effective nymph fly fishing requires precise and thoughtful technique.
In biology, the term nymph refers specifically to the pre-adult form of an insect that undergoes incomplete metamorphosis. In incomplete metamorphosis, the juvenile insect moults directly to an adult. There is no intermediate pupal stage or series of pupal stages. As such, only mayflies and stoneflies qualify as "nymphs" in the strict biological sense of the term. Caddis flies and midges undergo complete metamorphosis, so their particular larval imitations are often referred to as pupae rather than nymphs (though either is correct under the broad fly fishing usage of the term).
Sometimes a fly angler may hear some aquatic nymphs referred to as "naiads" or "ephydriads" after the mythical Greek water nymphs who would frequently seduce men into danger and death with their characteristic cold blackness. Check out earlier blogs for more on mythology in relation to fly fishing history.