Blue-winged Olives
Baetis
Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
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I was not fishing, but happened to be at an unrelated social event on a hill above this tiny creek (which I never even saw) when this stonefly flew by me. I assume it came from there. Some key characteristics are tricky to follow, but process of elimination ultimately led me to Sweltsa borealis. It is reassuringly similar to this specimen posted by Bob Newell years ago. It is also so strikingly similar to this nymph from the same river system that I'm comfortable identifying that nymph from this adult. I was especially pleased with the closeup photo of four mites parasitizing this one.
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Tiny Winter Blacks
Like most common names,"Tiny Winter Black" can refer to more than one taxon. They're previewed below, along with 5 specimens. For more detail click through to the scientific names.
Stonefly Family Capniidae
These are sometimes called Tiny Winter Blacks.
These are the first stoneflies of the year to appear in most parts of the country, and often the first aquatic insects noticed by the angler. Their dark brown or black bodies are easy to spot against the snowbanks where they crawl around.
Capnia in the West and Allocapnia in the East are probably the most common genera of this prolific family.
Capnia in the West and Allocapnia in the East are probably the most common genera of this prolific family.
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Stonefly Family Leuctridae
These are sometimes called Tiny Winter Blacks.
Leuctra is the only genus of any known importance to trout anglers. Their wings are rolled to a needle-like point; hence the common name, needle flies.
This is one of rarest stoneflies in western Montana. It is a bit unusual that it is fairly abundant in a handful of streams that empty into the east side of Flathead Lake. A very beautiful bug.
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Stonefly Family Nemouridae
These are sometimes called Tiny Winter Blacks.
A few of these tiny stoneflies were among the only species of aquatic insect adults in the air on this particular afternoon, with most of the action coming from a species of Epeorus mayfly. I somehow forgot to photograph this one on the usual ruler, but I recall it was very, very small, with an abdomen no more than 1mm in girth and the body, not counting the wings, probably just 5-7mm long.
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