Great Brown Spinners

This is the largest species of mayfly in North America. Sometimes it appears together with the Hexagenia limbata hatch or the Ephemera guttulata hatch, but in other places it creates excellent action on its own.

Timpanoga hecuba is not abundant enough, and its emergence not concentrated enough to provide great hatches, but where it is locally abundant it creates fishable action because of its large size. This species seems subject to substantial fluctuations in population densities, possibly in relation to the amount of silted habitat they prefer. When silt builds up in drought years, their numbers appear to increase. It is the largest species in the Ephemerellidae family, rivaling Drunella grandis (Western Green Drake) in length but appearing even stouter due to its dramatic lateral (Lateral: To the side.) abdominal spines. It contains two subspecies (Subspecies: Entomologists sometimes further divide a species into distinct groups called subspecies, which have two lower-case words on the end of their scientific name instead of one. The latter is the sub-species name. For example, Maccaffertium mexicanum mexicanum and Maccaffertium mexicanum integrum are two different subspecies of Maccaffertium mexicanum.). See the Timpanoga genus hatch page for details. There seems to be no preferred common name and anglers call them many things. Great Red Quill and Western Red Drake seem to fit best, though many refer to them as "Giant Dark Hendricksons".