Pale Watery Duns

Closely related to the important European "Spur Wings", a name given them due to the hook on the leading edge of their hindwings, these very small mayflies are usually reported in this country as inhabiting water too warm and/or stagnant for trout. But this is not always the case. Significant numbers have been reported in many cold water environments throughout the West. These tiny sulphurish mayflies are easy to confuse with small Pale Morning Duns which is perhaps the reason for their under-reporting by anglers. Their having only two tails is the easiest to way to tell the difference.

From an angling perspective, a downside of many taxonomic advances is the loss of what was thought to be the ability to use easily identifiable morphological differences for determining between genera. This is especially problematic in sorting out baetids. The truth is the old rule used by anglers involving the hindwings (i.e., spurwing - Centroptilum, no wing - Pseudocloeon, the rest - Baetis) has been dubious for years. They can no longer be applied as more has been learned about new genera and species properly reassigned. There are now some species of Centroptilum that lack hindwings altogether.

This is the most commonly mentioned species of Centroptilum in angling books, but very little detail is ever given about its hatches. It has been reported to inhabit warm water, but information regarding cold water habitat is sketchy.

This is the second most common Epeorus species in the East and Midwest. Most anglers will encounter sporadic hatches of Epeorus vitreus once in a while, and sometimes a more concentrated emergence causes a good rise of fish.