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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This seems to be a young larva of Limnephilus. Although not clear in the picture, several ventral abdominal segments have chloride epithelia.
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Identification: Key to Species of Caudatella Nymphs, Couplet 2
Identification: Key to Species of Caudatella Nymphs, Couplet 2
Adapted from Jacobus 2010 (2010)
| Option 1 | Option 2 |
|---|---|
| Paired medial spines on abdominal terga long and curved (at least on middle segments), some almost hook like | Paired medial spines on abdominal terga relatively straight, none longer than respective segment |
| Remaining species: Caudatella columbiella, Caudatella heterocaudata, and Caudatella jacobi | |
1 Example Specimen
This is a widely distributed species in western Montana but never abundant. Note the length of the middle tail, a key to the identification of this genus.
| |
| Caudatella hystrix | Go to Couplet 3 |
Adapted from Jacobus 2010 (2010)
The current couplet is highlighted with darker colors and a icon, and couplets leading to this point have a icon.
Leads to Caudatella edmundsi:
- Maxillary palp vestigial; tarsal claw with two prominent rows of denticles
Leads to Couplet 2:
- Maxillary palp with three distinct segments; tarsal claw with only one distinct row of denticles
Couplet 2
Couplet 2 (You are here)
Leads to Caudatella hystrix:
- Paired medial spines on abdominal terga long and curved (at least on middle segments), some almost hook like
Leads to Couplet 3:
- Paired medial spines on abdominal terga relatively straight, none longer than respective segment
Couplet 3
Leads to Caudatella jacobi:
- Cerci approximately two thirds length of median filament
- Abdominal sterna with solid color, never with longitudinal stripes or other such markings
Leads to Couplet 4:
- Cerci less than one-half length of median filament
- Abdominal sterna almost always with three dark, longitudinal markings
Couplet 4
Leads to Caudatella heterocaudata:
- Cerci approximately one-third length of median filament (about the length of the abdomen)
- Distinct pair of medial spines present only on abdominal terga 2–9, with the spine tips blunt
Leads to Caudatella columbiella:
- Cerci approximately one-sixth length of median filament (about half the length of the abdomen)
- Distinct pair of medial spines present on abdominal terga 1–9, with the spine tips sharp
Start a Discussion of this Couplet
References
- Jacobus, Luke M. 2010. Taxonomic Review of the Caudatella heterocaudata (McDunnough) and C. hystrix (Traver) Complexes (Insecta: Ephemeroptera: Ephemerellidae). Psyche: A Journal of Entomology 2010: 1-5.