The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
This field guide puts essential hatch-matching information at your fingertips wherever you have internet service. Pull up the mobile-friendly page
to see the likely aquatic insects for your location and time of year, with pictures for quick identifications, highlights of
each species' life cycle (timing, habitat, behavior), and tips for fly selection and presentation to catch more trout.
Identify trout stream insects using the same scientific criteria as entomologists, but with features to make the job
easier, including instant definitions of unfamiliar terms, extensive closeup photos, built-in range maps, example specimens, and easy
backtracking. Whether you're a biologist, a bug-serious angler, or looking to become one, these keys will make insect identification
faster and more fun.
Mayflies are the most important insects for anglers to understand, because they are common on trout streams, they often hatch in frenzied bursts of activity, and their behavior varies so widely between families and sometimes even species that it's useful to know and imitate the habits of each. They are a primitive order of insects, and their elegance and delicate lives have made them popular beyond the world of trout fishing.
Some anglers consider caddisflies to be even more important than mayflies. On many rivers, they're right. Angler-entomologists focus less energy on them because they are slightly less prone to cause a feeding frenzy among the trout. Although that happens sometimes, they are more commonly an intermittent food source during the times when it seems like nothing's hatching. Understanding their life cycle is of paramount importance to any fly fisher, but learning their species-specific idiosyncrasies is less useful than with mayflies.
Though less prolific than mayflies and caddisflies, many stonefly species make up for in size what they lack in numbers. Because they emerge by crawling out of the water on land, the hatching adults are not eaten for trout, but their large nymphs are welcome food year-round. In the Western states, where stoneflies are most prolific, trout sometimes feed selectively on the egg-laying adults as they return to the water.