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Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York
Blue-winged Olives

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.

Dorsal view of a Pycnopsyche guttifera (Limnephilidae) (Great Autumn Brown Sedge) Caddisfly Larva from the Yakima River in Washington
This specimen appears to be of the same species as this one collected in the same spot two months earlier. The identification of both is tentative. This one suffered some physical damage before being photographed, too, so the colors aren't totally natural. I was mostly photographing it to test out some new camera setting idea, which worked really well for a couple of closeups.
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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Mayfly Family Siphlonuridae (Gray Drakes)

These large, slender mayflies have nymphs of the swimming type, like Isonychiidae and Metretopodidae, and they generally inhabit slow water. See Siphlonurus for details -- it is the only genus of known importance to anglers.

Where & when

In 251 records from GBIF, adults of this family have mostly been collected during June (49%), July (27%), May (11%), and August (10%).

In 489 records from GBIF, this family has been collected at elevations ranging from -30 to 11444 ft, with an average (median) of 810 ft.

Family Range


To determine whether a specimen of Ephemeroptera belongs to Siphlonuridae, use the Key to Families of Mayfly Nymphs or Key to Families of Mayfly Duns and Spinners.

Specimens of the Mayfly Family Siphlonuridae

2 Female Duns
5 Male Spinners
7 Female Spinners
10 Nymphs

3 Underwater Pictures of Siphlonuridae Mayflies:

Start a Discussion of Siphlonuridae

Mayfly Family Siphlonuridae (Gray Drakes)

Genus in Siphlonuridae: Parameletus, Siphlonisca, Siphlonurus
1 genus (Edmundsius) isn't included.
Family Range
Common Name
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