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.
|Option 1||Option 2|
|Ventral gill tufts present on thorax and abdominal segments 1-2 or 1-3 ||Ventral gill tufts absent from abdominal segments 1-2 or 1-3 |
|Remaining families: Capniidae, Chloroperlidae, Leuctridae, Nemouridae, Peltoperlidae, Perlidae, Perlodidae, and Taeniopterygidae|
5 Example Specimens
This salmonfly nymph is probably not quite fully grown, as it still has a couple months yet to emerge.
5 Example Specimens
This striking golden stonefly is the first of its species I've had the chance to photograph.
I'm not aware of any way to tell the two species of Doroneuria apart as nymphs, so this one is classified to species based on location alone. Doroneuria baumanni is found in the Cascades and in Washington, and the other species is not known here yet.
(Edit: I'm putting a species ID on this one based on the great similarity of its markings to those of an adult I collected in 2023 from a tributary of the same river at around the same time of year.)
This one was tricky to identify. The "thick, depressed dark clothing hairs" on the thoracic sterna inside the coxae, which indicate Sweltsa, are fairly sparse and very difficult to see in my photos, although more apparent under the microscope. However, if I decide those hairs are too sparse to be "thick" and follow the key, I end up pretty clearly at Haploperla. However, Haploperla should have the inner margin of the hind wingpads approximately parallel to the body axis, and they're clearly divergent on this specimen. The pronotal fringe hairs should also be longer than they are in this specimen. So following that whole branch of the key was probably wrong, which leads back to this one being Sweltsa. Unfortunately, nymphs have only been described for a small number of Sweltsa species.
I found just a few of these nymphs alongside a much larger number of bland, typical Sweltsa nymphs.
|Pteronarcyidae||Go to Couplet 2|