A Framework for Fly Fishing Entomology

This is the first lesson of our paid entomology course that we offer for free so you can see what it looks like and works like.  If you like what you see, you can buy the full course here.

­­Practical Entomology for Fly Fishing

This course will teach you how to match any bug you see in a trout river or lake with a fly in your box so you can catch more fish on your fly fishing adventures.  By the end of this course you will be able to:

  • Properly collect bugs in the water that trout are likely eating
  • Select a similar fly in your box that’s suited for the presentation you wish to make
  • Identify any insect on the river based on it’s order and stage
  • Catch more fish
You’ll also get these great freebies:
  • Three 50% off coupons for our online fly shop (or the partner site you purchased this course through) you’ll get flies for $0.80 with these coupons. You’ll save over $10.00 per dozen, average orders are usually 4-6 dozen at our shop, so you can easily save over $150 in flies based on what you buy.
  • Free bug seine – 18” x 18” with an elastic band to stretch around any net.  It’s used to collect insects in a lake or river. Retails at $24.99
  • A direct Q&A link to ask me, the author, questions about anything fly fishing including my personal email address.

I have used this knowledge in this course to catch literally thousands of fish in four different countries and on hundreds of rivers.  This information is universal to any trout habitat.  Some information you’ll need to memorize, other information you’ll need to practice.  Most people who apply this information, that didn’t know it before, double the amount of fish they catch each time they go out.

That’s why you paid for this course and that’s what we deliver.

First off, don’t get overwhelmed , you don’t have to learn a million bugs.  You really just need to understand how to identify the common characteristics of the major groupings (orders) of insects.  The next step is to identify the stage the insect is in.  The last step is to identify if the trout are likely feeding on this insect currently.  Once you know that information, you can easily select a bug in your box and fish it correctly to catch more fish.

Let’s begin with an overview of 3 important topics:

  • Orders of Insects
  • Insect Stages
  • Insect Behavior as it Applies to Trout

This is the general outline for what you will do on the river with the knowledge you learn here.

Orders of Insects

Click on images to enlarge

Order of insects is the common way to state the categories of insects that exist in a river.

There are 8 major orders as it applies to fly fishing and fly selection.  To make it easier, we grouped some orders together because of their similarity in the way or location you fish them.

  • Midges
  • Mayflies
  • Caddis
  • Stoneflies
  • Terrestrials
  • Scuds & Sowbugs
  • Annelids
  • Damsel/Dragon Flies/Water Boatman

Memorize these orders, especially the first 4, which make up at least 80% of the insects trout eat.  Most flies in your box match or imitate these categories (including some streamers). You’ll need to know these orders when you find a bug in the river and need to know what to call it.  Throughout this course we will go through order by order and show you how to identify, match and fish these orders of insects.

This is the last time I’ll state it for all you biology nuts out there trying to crack me.  This is not a scientific approach, that belongs in the text books.  Damsels and Dragon flies are very different, but not in ways that matter to the fly fisherman.  So lay off the criticism and enjoy the course :).

Identify the Insect Stage

fishing flies by stageInsects go through metamorphosis, which means they change shape, colors and more, much like a butterfly.  The changes they make are set into distinct stages that an angler then matches with his fly selection.  Here are the stages all insects go through that matter to anglers:

  • Nymph Stage – This is the subsurface stage all aquatic insects have and make up 4/5’s of the trout’s diet, according to Gallup’s latest study on the dining habits of trout. (that was a joke if you didn’t catch the sarcasm).  They are however, very critical to a trout’s diet, many fish are caught on nymphs.
  • Emerger Stage– The red-headed step child of the insect stages. Most forget, but nearly all of the insects trout feed on go from nymph to dry fly stages in the water and thus have an “emergence” stage that leaves them helpless. Think of a butterfly half out of his cocoon, floating down the river.  If a trout could hashtag, he’d say #smorgasbord.
  • Dry Fly Stage – This is the primary stage most anglers like to target cause let’s face it, it’s more fun than staring at an indicator for hours. They are critical to a trouts diet from spring to fall.  They can even be valuable in the winter with the right locations and conditions.
  • Spinner Stage – This is the stage where the dry flies have made their sweet lovin’ with their partners and taken their last breath. Some, but not all insects mate over the water.  Those that do often have a spinner fall where they fall back onto the water dead and the trout slurp them up.  Mayflies are the most common example of this stage.

There is a secret bonus stage too called a pupa, which happens between the nymph and emerger and it’s like a cocoon stage, but most of the time, we don’t get into that level of detail on our flies we imitate.  (caddis and midge are the exceptions)

Memorize the 4 stages, pair that with your knowledge of orders and you’ll be able to classify any insect on the river.  We’ll go a bit further into detail and take a look at some diagrams to practice identifying each order and the stage within that category ensuring you really know your stuff on the river.

Insect Behavior


mayfly nymph
mayfly nymph

Insect behavior is the third piece to the fly selection puzzle.  Understanding that caddis often prefer faster water, or that stoneflies hatch on the banks instead of within a river, are critical to catching fish and selecting the right fly.

Keep in mind that a common myth is that just because you can see a caddis flying around, doesn’t mean that’s what the fish are eating.  Depending on your location, time of day and other factors we’ll explain in greater detail later; you will know if the insect you just found has any link to your ability to catch trout.

So equipped with those 3 domains we just covered, you’ll be able to match any insects to flies in your boxes.  Let’s now dive into the meat of the course and go through; order by order, stage by stage the:

  • Location of the Insect, both regionally and within the river itself including insect behavior
  • Seasons of most importance for that insect
  • Life Stages the insect has and how to identify the stage
  • Common variations/colors and sizes of flies used to imitate the order/stage
  • 1-3 tips on how to best fish this order/stage


Next Lesson | Midges

Learn About Midges

Learn Exactly How to Identify Any Insect & Catch More Fish

Fully Online | Self Paced | Lifetime Access

Online Entomology Course

  • Become a Fly Selection Artisan
  • Get Forever Access, Including Content Updates
  • Get Three, 50% Off Coupons for Flies
  • Get a Free Bug Seine to Catch Insects

Complete Course for Life: $199.99
On Sale: $99.50 (50% Off)

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Course Outline

  • Length: 7 pages | Video: 3m 14s

    In our introduction, we lay out the framework and tools needed to identify any insect, anywhere in the world, and match it to a fly in your box. We cover insect orders, stages, and insect behaviors. With this information, the rest of the course flows together perfectly and makes it easy to retain the knowledge when you’re on the river.

  • Length: 16 pages | Video: 1m 59s

    Midges are present in a river and lake system year round making them a key insect to understand and identify when you’re on the water. Learn how to identify a midge in all stages, match it to a fly in your box and catch more fish. Includes tips on how to fish each stage of midge insects

  • Length: 19 Pages | Video 1m 12s

    Mayflies are the most diverse insect a fly fisherman needs to identify and understand. Learn the stages, flies to use, how to fish those flies and common hatches, colors and sizes to watch out for in the river and lakes around the world.

    In addition, since mayflies are so prevelant, we address all the common species like Baetis, PMD, Callibaetis, Tricos, Hex, Isonychia, Green Drakes, March Browns, Hendricksons, Cahills, and even the famous Adams (FYI, no such mayfly as an adams, if you didn’t know that, you probably need this course.)

  • Length 12 Pages | Video 1m 25s

    Caddis are an exciting and highly important insect to trout. Learn what stages hold the most importance to trout and how to match them to flies in your box. We also provide some critical tips to improve your presentation on the river.

  • Length 22 Pages | Video 3m 11sec

    We cover the most exciting bugs to fish in this lesson – stoneflies and terrestrials. Though not alike in many ways, they are fun to fish and are known for producing great summer fishing. Learn about the elusive stonefly and the coveted terrestrials including patterns and tips on how to fish them.

    We grouped stoneflies and terrestrials together only to keep length lessons similar. Stoneflies only have two stages and terrestrials only have one that we as anglers have to worry about, so it makes good sense to add them into one lesson. Otherwise, there is really no comparison between the two.

  • Length: 10 pages | Video: 1m 23s

    These insects are fully aquatic and don’t hatch, yet they hold a vital importance to a trout’s diet. Learn about the underworld life of scuds, sowbugs and annelids (worms) so you can catch more fish, especially on tailwaters.

  • Length: 19 Pages | Video 1m 12s

    Fly anglers who love fishing lakes need to pay special attention to this lesson. However, if you prefer rivers, you’d be surprised how many of these insects reside in your local waters and are important to trout throughout the seasons. Learn the insects, patterns and tips on fishing them in this lesson.

  • Length 12 Pages | Video 2m 32s

    In the final lesson, we address some easy tips and tricks to apply the knowledge, a larger framework for understanding how to catch fish anywhere, and anytime.  We also provide some epic resources you can print and keep with you that are easy identification guides and hatch charts for insects.