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

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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Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva

Lateral view of a Onocosmoecus (Limnephilidae) (Great Late-Summer Sedge) Caddisfly Larva from the Yakima River in Washington

This specimen keys pretty easily to Onocosmoecus, and it closely resembles a specimen from Alaska which caddis expert Dave Ruiter recognized as this genus. As with that specimen, the only species in the genus documented in this area is Onocosmoecus unicolor, but Dave suggested for that specimen that there might be multiple not-yet-distinguished species under the unicolor umbrella and it would be best to stick with the genus-level ID. I'm doing the same for this one.

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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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Hesperophylax (Silver Striped Sedge) Caddisfly Larva Pictures

Based on both range maps and key characteristics, this larva is either Hesperophylax designatus, Hesperophylax alaskensis, or Hesperophylax occidentalis. However, the species key in Parker & Wiggins (1985) cannot separate these species as larvae.

Hesperophylax (Limnephilidae) (Silver Striped Sedge) Caddisfly Larva from the South Fork Snoqualmie River in Washington

Case view of a Hesperophylax (Limnephilidae) (Silver Striped Sedge) Caddisfly Larva from the South Fork Snoqualmie River in Washington

Ruler view of a Hesperophylax (Limnephilidae) (Silver Striped Sedge) Caddisfly Larva from the South Fork Snoqualmie River in Washington The smallest ruler marks are 1 mm.

Dorsal view of a Hesperophylax (Limnephilidae) (Silver Striped Sedge) Caddisfly Larva from the South Fork Snoqualmie River in Washington

Ventral view of a Hesperophylax (Limnephilidae) (Silver Striped Sedge) Caddisfly Larva from the South Fork Snoqualmie River in Washington

This caddisfly was collected from the South Fork Snoqualmie River in Washington on June 13th, 2019 and added to Troutnut.com by Troutnut on June 15th, 2019.

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References

Parker, C. R., Wiggins, G. B. 1985. The Nearctic Caddisfly Genus Hesperophylax Banks (trichoptera: Limnephilidae). Canadian Journal of Zoology 63(10): 2443-2472.