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Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

Lateral view of a Male Baetidae (Blue-Winged Olive) Mayfly Dun from Mystery Creek #308 in Washington
This dun emerged from a mature nymph on my desk. Unfortunately its wings didn't perfectly dry out.
27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.
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Red Speckled Dun

This common name refers to only one species. Click its scientific name to learn more.

Mayfly Species Callibaetis ferrugineus

These are very rarely called Red Speckled Dun.
The sub-species Callibaetis ferrugineus ferrugineus and Callibaetis ferrugineus hageni taken together are by far the most important Callibaetis taxon in American trout waters. In extant angling literature, the sub-species ferrugineus ferrugineus inhabiting the east and Midwest is referred to as ferrugineus sans the sub-species name. In the West, Callibaetis ferrugineus hageni is referred to by many old and familiar synonyms, such as americanus, nigritus, and coloradensis. While important in the East and Midwest, it is in the West where Callibaetis ferrugineus hageni has achieved legendary status. Many western stillwater anglers look to the hatches of these speckled duns and spinners as the highlight of their seasons and have coined the phrase "gulpers" to describe the trout's feeding activity. In the West, some spring fed lower elevation lakes with longer growing seasons can produce as many as three discrete broods. In typical baetid fashion, these broods will be larger and darker in the Spring tending smaller and lighter as the season progresses.
Female Callibaetis ferrugineus (Baetidae) (Speckled Dun) Mayfly Dun from unknown in Wisconsin
Female Callibaetis ferrugineus (Baetidae) (Speckled Dun) Mayfly Spinner from the Flathead River-lower in Montana
These adults are probably C. ferrugineus.
Lateral view of a Callibaetis ferrugineus (Baetidae) (Speckled Dun) Mayfly Nymph from Mystery Creek #304 in Idaho
This nymph was one of a horde I could see cruising the still shallows of a cold tailwater, mixed in with an intense emergence of duns. It's one of four specimens I photographed together from the same hatch, also including a male dun, a female dun, and a male spinner.

This nymph keys to either Callibaetis ferrugineous or Callibaetis pallidus. The lack of a darkened preapical band on the femora would suggest pallidus, but I can't definitively make out the "single seta" on the outer, ventral apex of any of the tarsi, the length of which is supposedly a more reliable characteristic to tell the species spart. I can maybe make something out on one of the legs at the highest magnification, and its dimensions would suggest ferrugineous.

Red Speckled Dun

Scientific Name
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