Header image
Blue-winged Olives

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.

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 digital format that makes them easier to use. If you're new to keys, see my Introduction to Taxonomic Keys.

High-level keys

Mayfly keys

Caddisfly keys

Stonefly keys

True fly keys (midges, etc.)

Troutnut.com is copyright © 2004-2022 (email Jason). privacy policy