The hatch chart below covers the state of Pennsylvania. Dates are approximate. Cooler or warmer temperatures can speed up or delay the time of emergence.
Common Name | Scientific Name | Date of Emergence | Time | Size |
Little Blue Wing Olive | Baetis tricaudatus | April 1 | Late Morning | 16 – 20 |
Blue Quill | P. adoptiva | April 18 | Late Morning | 18 |
Dark Quill Gordon | Ameletus ludens | April 18 | Afternoon | 14 |
Quill Gordon | Epeorus pleuralis | April 20 | Early Afternoon | 14 |
Hendrickson | E. subvaria | April 21 | Early Afternoon | 14 |
Black Quill | Leptophlebia cupida | April 25 | Early Afternoon | 14 |
Great Speckled Olive Dun | Siphloplecton basale | April 20 | Early Afternoon | 14 |
Little Blue Dun | Acentrella carolina | May 1 | Afternoon/Evening | 20 |
Sulphur Dun | E. rotunda | May 12 | Evening | 16 |
Gray Fox | Stenonema fuscum | May 15 | Afternoon | 12-14 |
Pale Evening Dun | E. septenttrionalis | May 15 | Evening | 14-16 |
Pale Evening Dun | Heptagenia aphrodite | May 18 | Evening | 16 |
March Brown | Stenonema vicarium | May 18 | Morning/Afternoon | 12-14 |
Light Cahill | Stenacron interpunctatum | May 23 | Evening | 14 |
Chocolate Dun | E. bicolor | May 25 | Morning/Afternoon | 16 |
Green Drake | E. guttulata | May 25 | Evening | 8-12 |
Brown Drake | E. simulans | May 25 | Evening | 10-12 |
Light Cahill | Stenonema ithaca | May 25 | Evening | 14 |
Dark Green Drake | Litobrancha recurvata | May 25 | Afternoon/Evening | 6-10 |
Slate Drake | Isonychia sadleri | May 25 | Evening | 12 |
Cream Cahill | Stenonema modestum | May 25 | Evening | 14-16 |
Blue Wing Olive Dun | E. drunella comuta | May 25 | Late Morning | 14 |
Blue Wing Olive Dun | E. drunella longicomus | May 25 | Early Morning | 16 |
Pink Cahill | Epeorus vitreus | May 25 | Evening | 14-16 |
Sulphur Dun | E. invana | June 1 | Evening | 16-18 |
Dark Blue Quill | E. seratella deficiens | June 1 | Evening | 16-20 |
Blue Quill | P. mollis | June 3 | Morning/Afternoon | 18 |
Iron Blue Dun | L. johnsoni | June 5 | Late Morning | 16 |
Little Blue Wing Olive Dun | Baetis levitans | June 5 | Afternoon/Evening | 20 |
Little Blue Wing Olive Dun | E. drunella simplex | June15 | Morning/Afternoon | 18-20 |
Little Blue Wing Olive Dun | E. drunella lata | June 15 | Morning/Afternoon | 16 |
Light Cahill | Leucrocuta marginalis | June 15 | Evening | 14 |
Cream Cahill | Stenonema pulchellum | June 15 | Evening | 14-16 |
Sulphur Dun | Ephemerella dorothea | June 15 | Evening | 18 |
Yellow Drake | Ephemera varia | June 20 | Evening | 12 |
Blue Quill | P. guttata | June 25 | Morning | 18 |
Golden Drake | A. distinctus | June 25 | Evening | 12-14 |
Pale Evening Dun | Heptagenia species | June 25 | Evening | 16 |
Pale Morning Dun | Centoptilium | July 15 | Morning | 22 |
Little White Mayfly | Caenis species | July 15 | Evening | 28 |
Trico | Tricorythodes species | July 15 | Morning | 24 |
Slate Drake | Isonychia harpei | July 23 | Evening | 12-14 |
White Mayfly | Ephoron leukon | August 15 | Evening | 14-16 |
Big Slate Drake | Hexagenia atrocaudata | August 18 | Evening | 8 |
Slate Drake | Isonychia bicolor | August 25 | Afternoon/Evening | 14 |
Little Blue Wing Olive | Baetis tricaudatus | September 1 | Afternoon | 16-20 |
Little Blue Dun | Acentrella carolina | September 15 | Afternoon | 20 |
Caddis and Stoneflies
Common Name | Scientific Name | Date of Emergence | Time | Size |
Little Olive Caddis | Hydropsyche bronta | April 10 | Morning/Afternoon | 16 |
Little Black Caddis | Chimarra atterima | April 15 | Late Morning | 18 |
Grannom | Brachycentrus numerosus | April 20 | Morning/Afternoon | 12 |
Cream Caddis | Psilotreta species | April 25 | Morning/Afternoon | 14 |
Green Caddis | Rhyacophila species | May 1 | Morning/Afternoon | 14 |
Dark Brown Caddis | Deplectrona species | May 15 | Morning/Afternoon | 12 |
Little Black Stonefly | Capnia vemalis | March 1 | Morning/Afternoon | 16 |
Early Brown Stonefly | Strophopteryx fasciata | April 29 | Noon | 14 |
Great Brown Stonefly | Phasganophora capitata | April 20 | Morning/Afternoon | 12 |
Light Stonefly | Isoperla signata | May 8 | Afternoon | 14 |
Spotted Sedge | Symphitopsyche slossanae | May 23 | Afternoon | 14 |
Dark Blue Sedge | Psilotreta frontalis | June 5 | Evening | 12 |
Yellow Sally | Isoperla bilineata | June 5 | Afternoon | 14 |
Little Green Stonefly | Alloperla imbecilla | June 5 | Afternoon | 16 |
Great Stonefly | Phasganophora capitata | June 5 | Afternoon/Evening | 10 |
Great Brown Stonefly | Acroneuria lycorius | June 15 | Morning/Afternoon | 12 |
Green Caddis | Rhyacophila species | July 10 | Morning/Afternoon | 14 |