Standard Black Baetis Nymph
I developed these patterns about 13 years ago on the Big Horn. They have the same abdomen style as the Lunar series. 90% of your small mayfly nymphs instream are an olive cast. The other 10% are brown (see my Twinkle Tail Nymph). I also noticed how dark the Baetis Nymphs become within about 1 week of emergence, so I came up with the killer Black Baetis. Many guides on the ‘Horn still beg me to tie this pattern for them. Both of my Baetis Nymph patterns come in std shiny back, or holographic flashback.
Note on Hook Sizing: Tiemco 3x long nymph hook (#200R). Again my #20 is roughly equivalent to a #18 standard dry fly hook in overall size.