Large Blue-Winged Olives

This species is best known for the summer morning action it creates in the East and Midwest. It is prolific but the emergence is often sporadic and sparse, which means it is often upstaged by blizzards of tiny Tricorythodes mayflies and other more concentrated hatches.

Recent taxonomic changes have served this species well, because several other popular species (Drunella cornuta, Drunella cornutella, and Drunella longicornis) are now recognized as synonyms (Synonym: A former name of a taxon, usually a species. Entomologists frequently discover that two insects originally described as different species are one in the same, and they drop one of the names. The dropped name is said to be a synonym of the remaining name. These changes take a while to trickle into the common knowledge of anglers; for example, Baetis vagans is now a synonym of Baetis tricaudatus.) of Drunella lata. The combined lata hatch now lasts for months.

Angling entomology books show several differences in hatching behavior between the former species now combined with lata. I've tried to parse these into a coherent picture here based on the geography of the old species, but I recommend consulting experienced local anglers to understand which of the many variations on lata behavior is prevalent in your area.

This is the second most common East-Midwest Drunella species, but it is not very important compared to Drunella lata. Ernest Schwiebert had this to say about their hatches:

An imitation is rarely required, but notes show that when it is needed it is needed badly.