White Clay Fly Fishers

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Pennsylvania Hatches

Dates are approximate. Cooler or warmer temperatures can alter the times of emergence.

Mayflies

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

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