As with any hatch chart, this is only a guide to when you can expect certain flies to hatch. The weather, water levels and just the overall type of season will affect the actual periods of bug activity. Some of the hatches occur throughout the river system, while others are more prolific in specific sections. Just another reason why a full time professional fly fishing guide can make your visit to the river more enjoyable and productive.
If you look through the chart you will notice some overlap among the various hatches. This often translates to having multiple insect species hatching at the same time. On top of this, add fish that are keyed into one specific specie and then into one specific life stage of that insect. It gets interesting.
Insect | Artificial | Size | Dates* |
Taeniopteryx fasciata | Brown Stone | 12/14 | 3/25-5/5 |
Baetis vagans | Blue Winged Olive | 18/20 | 3/25- 5/15 |
Chimarra | Little Black Caddis | 18/20 | 4/1 - 5/20 |
Paraleptophlebia adoptiva | Blue Quill, Mahogany Dun | 18/20 | 4/10 - 5/10 |
Epeorus pleuralis | Quill Gordon | 12/14 | 4/10 - 5/15 |
Ephemerella subvaria | Hendrickson | 12/14 | 4/15 - 5/25 |
Ephemerella invaria | Sulfur | 12/14 | 4/20 - 6/10 |
Brachycentrus | Shad Fly, Grannom Caddis | 16 | 4/25 - 5/25 |
Ephemerella rotunda | Sulfur/Pale Evening Dun | 12/14 | 5/1 - 6/10 |
Stenonema vicarium | March Brown | 10/12 | 5/15 - 6/5 |
Stenonema fuscum | Gray Fox | 12/14 | 5/25 -6/20 |
Ephemerella dorothea | Sulfur | 16/18 | 5/25 - 7/15 |
Ephemera guttulata | Green Drake | 8/10 | 6/1 - 6/15 |
Epeorus vitreus | Sulfur | 12/14 | 6/1 - 8/10 |
Isonychia bicolor | Dun Variant, Slate Drake | 10/12 | 6/1 - 10/31 |
Stenonema Ithaca & canadense | Light Cahill | 12/14 | 6/5- 9/10 |
Ephemerella cornuta | Blue Winged Olive | 14 | 6/5 - 6/25 |
Ephemerella atenuata | Blue Winged Olive | 18/20 | 6/15 - 7/15 |
Ephemera simulans | Brown Drake | 8/10 | 6/5- 6/15 |
Potamanthus | Cream Variant | 10 | 6/15 - 8/25 |
Tricorythodes | Trico | 24 | 6/28 - 10/15 |
Pseudocloeon | Blue Winged Olive | 24 | 6/28 - 11/20 |
Ephemerella lata | Blue Winged Olive | 22 | 7/15 - 11/24 |
Paraleptophlebia debilus | Blue Quill | 16/18 | 7/1 - 10/15 |
Ephoron leukon | White Fly | 12/14 | 8/20 - 9/15 |
*The first date listed is usually the earliest you can expect particular