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

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

Dorsal view of a Grammotaulius betteni (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington
This is a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
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.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Identification: Key to Orders of Aquatic Insect Nymphs, Couplet 4

Identification: Key to Orders of Aquatic Insect Nymphs, Couplet 4

Option 1Option 2
Tarsi almost always with one claw Tarsi with 2 claws
Usually 3 tails, but sometimes 2 Always 2 tails
Plate-like, filamentous, or feathery gills located on sides of abdomen, often present on most middle abdominal segments


Finger-like or feathery gills present, but sometimes inconspicuous at base of mouthparts, head, legs, first few abdominal segments, or last abdominal segment

Figure from this Peltoperla nymph.
5 Example Specimens
5 Example Specimens
Ephemeroptera

Continue to the Key to Families of Mayfly Nymphs

Plecoptera
The current couplet is highlighted with darker colors and a icon, and couplets leading to this point have a icon.
Leads to Couplet 2:
  • Chewing mouthparts, with mandibles distinct
Couplet 2
Leads to Hemiptera:
  • Sucking mouthparts, united in a jointed beak with mandibles concealed
Leads to Orthoptera:
  • Hind legs suitable for jumping, with hind femora greatly enlarged
  • Abdomen with short tails
  • Found in moist places and only temporarily in water
Leads to Couplet 3:
  • Hind legs suited for crawling, with hind femora similar in size to front and middle femora, not greatly enlarged
  • Abdomen with or without conspicuous tails
  • Usually submerged and truly aquatic
Couplet 3
Leads to Couplet 5:
  • Labium (lower lip) mask-like, extendable into a scoop-like structure longer than head
Couplet 5
Leads to Couplet 4:
  • Labium normal, smaller than head, not large and mask-like
Couplet 4
Couplet 4

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Couplet 4 (You are here)
Leads to Ephemeroptera:
  • Tarsi almost always with one claw
  • Usually 3 tails, but sometimes 2
  • Plate-like, filamentous, or feathery gills located on sides of abdomen, often present on most middle abdominal segments
Leads to Plecoptera:
  • Tarsi with 2 claws
  • Always 2 tails
  • Finger-like or feathery gills present, but sometimes inconspicuous at base of mouthparts, head, legs, first few abdominal segments, or last abdominal segment
Leads to Odonata-Zygoptera:
  • Body slender, with head wider than thorax and abdomen
  • 3 long, caudal tracheal gills at the tip of the abdomen resemble paddle-like tails
Leads to Odonata-Anisoptera:
  • Body stout, with head usually narrower than thorax and abdomen
  • 5 short, stiff, pointed appendages at the tip of the abdomen

Start a Discussion of this Couplet

References

Orders excluded
These orders of Insecta are not included in this key: Trichoptera, Diptera, Coleoptera, Megaloptera, Lepidoptera, Hymenoptera, Neuroptera, Psocodea
Description of this key
This key only covers insect orders whose juvenile stages are typically referred to as nymphs. Invertebrates that have larvae instead are not included.
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