Speckled-Winged Duns

These mayflies are a sleeper hatch which has barely received a nod in the fly fishing literature. Their abundance never matches that of the classic superhatches, but their importance can.

Their primary claim to fame is their peculiar shape, both as nymphs and as adults. On most rivers they are a rare oddity, but there are places where their spinner falls elicit greedy rises and staunch selectivity from the trout. These spinners never even come close to blanketing the water, but trout have such an affinity for them that even their sparsest falls should excite the angler.

I favor two explanations for their importance. First, they have a very stout profile, and late-season beetle action suggests that trout like this trait. Second, the Baetisca action lasts for up to a month on a single stretch of water. This caters to the selective trout's love of the familiar.

Callibaetis mayflies, among the largest in the Baetidae family, reside only in slow or still water. The most important species is Callibaetis ferrugineus, which is found across the country but produces its best hatches in the West.

The duns and spinners are easily recognized by their distinctive wings, a dark background overlayed with light veins -- see the pictures.