I dont know about out west but here in the south we dont have #12 BWO's
This is the fly fisher's *glitch* in describing insects with names of imitations. When I lived back in PA most anglers carried Blue-winged Olives in sizes 14 thru 24. There were about 12-13 mayfly species that could be described as (or imitated by) a Blue-winged Olive pattern.
Drunella lata (formerly
Ephermerella cornuta) is the original Blue-winged Olive of the Northeast commonly imitated with size 14-16. Some still call them Cornuta's.
The many species of
Baetis (
vagans, quebecensis, others) are commonly called Little Blue-winged Olives. Although most just refer to them as "Baetis" now... they range hook size 16-20.
Then you've got the
Cloeons and
Pseudocloeons (forget what their updated taxon is now) which are the Tiny Blue-winged Olives. These are commonly size 20-26.
There's some oddball stuff too -
A. attenuata, E. depressa, P. dubius, ranging hook size 16-26 and all would be imitated with Blue-winged Olives.
Moving out west it seems that the moniker Blue-winged Olive is reserved for just the
Baetis species, and the Drunella's western cousin's are called out either by their scientific nicknames (
D. flavilinea are called Flav's) and their bigger cousins -
D. grandis, doddsi, and
glacialis are referred to as Green Drakes. Which are much smaller, and look nothing like the Green Drakes back east (
Ephemera guttulatta).
Woo, I need a drink.
