Salmonflies
Pteronarcys californica
The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
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It's only barely visible in one of my pictures, but I confirmed under the microscope that this one has a prosternal horn and the antennae are mid-way between the eyes and front of the head capsule.
I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.
The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.
Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.
The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.
Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
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Identification: Key to Orders of Aquatic Insect Nymphs, Couplet 3
Identification: Key to Orders of Aquatic Insect Nymphs, Couplet 3
Error: Tried to access a key that isn't live.
Adapted from Merritt R.W., Cummins, K.W., and Berg, M.B. (2019)
| Option 1 | Option 2 |
|---|---|
| Labium (lower lip) mask-like, extendable into a scoop-like structure longer than head | Labium normal, smaller than head, not large and mask-like |
| Remaining orders: Odonata-Anisoptera and Odonata-Zygoptera | Remaining orders: Ephemeroptera and Plecoptera |
5 Example Specimens | 5 Example Specimens
This striking golden stonefly is the first of its species I've had the chance to photograph.
This Isonychia bicolor nymph from the Catskills displays the prominent white stripe sometimes characteristic of its species. This is the first such specimen I've photographed, because members of the same species in the Upper Midwest have a more subdued stripe (and were once thought to be a different species, Isonychia sadleri). The striking coloration on this eastern nymph is more appealing.
|
| Go to Couplet 5 | Go to Couplet 4 |
Adapted from Merritt R.W., Cummins, K.W., and Berg, M.B. (2019)
The current couplet is highlighted with darker colors and a icon, and couplets leading to this point have a icon.
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
Couplet 3 (You are here)
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
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
- Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.
Orders excluded
These orders of Insecta are not included in this key: Trichoptera, Diptera, Coleoptera, Megaloptera, Lepidoptera, Hymenoptera, Neuroptera, Psocodea