I was explaining fly fishing terms to my sister and she asked an interesting question - does the "D" in PMD stand for the adult mayfly or the color? I immediately said adult mayfly, but she said if that is the case then the terms "PMD nymph" or "PMD emerger" didn't make sense. Then I started thinking that I have seen the term "PMD adult", which would be redundant.

Just another thing to confuse me. Does anybody know the true origin of the term "PMD"?

Joe