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Salmonflies
Pteronarcys californica

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

Taxonomic Keys for Aquatic Invertebrate Identification

The taxonomic keys on this website are adapted from a variety of books and scientific papers, and they represent the combined hard work of hundreds of entomologists over many decades. I claim no credit for creating them, only arranging them in a more user-friendly format and adding some illustrations. These keys only cover North American taxa. If you're new to keys, see my Introduction to Taxonomic Keys.

High-level keys

Mayfly keys

Mayfly family keys to genus

This list includes keys to genus for all North American mayfly families.

Adult stage (male spinners)
Nymph stage

Mayfly genus keys to species

Only a small number of keys all the way to species are online yet, but that's an ongoing project.

Adult stage (male spinners)
Nymph stage

Caddisfly keys

Caddisfly family keys to genus

This list includes keys to genus for all North American caddisfly families.

Adult stage
Larval stage

Stonefly keys

Stonefly family keys to genus

This list includes keys to genus for all North American mayfly families.

Adult stage
Nymph stage

True fly keys (midges, etc.)

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