Author and Fly Fisherman
Charles  R. Meck
Hatch Chart

  Click on “Mayfly Identification”  for photos of some of the more common mayflies.

For more information on the hatches please purchase The Hatches Made Simple, Arizona Trout Streams,  Pennsylvania Trout Streams,  or Fishing Limestone Streams by clicking on “Books” at the bottom of this page.

Common Name of the dun, stonefly (S) or caddisfly (C)

Region Found

Hatch
date

Scientific Name

Time of day

Pattern
size

Where in the stream the nymph changes to dun

Type of water nymph inhabits

Little Black Stonefly-S

E, M & W

February 1

Capnia vernalis

Afternoon

14-18

O

M&F

Little Olive Dun (Trico)

W

February 15**+

Tricorythodes fictus

Morning

20-24

S or B

S

Western March Brown

W

February 25*

Rhithrogena morrisoni

Afternoon

14

T

M & F

Little Blue-Winged Olive Dun

E, M&W

January to December **

Baetis  intercalaris

Afternoon

20

B

M&F

 

Little Golden Stonefly-S

W

April  1

Skawala parallela

Afternoon

16

O

F

Little Blue-Winged Olive Dun

E, M &W

April 1

Baetis tricaudatus**

Afternoon

20

B

M&F

Speckle-Winged Dun

E & M

April 10

Callibaetis skokianis**

Morning &
 afternoon

14

B

S (prefers alkaline lakes)

Early Brown Stonefly-S

E&M

April 10

Strophopteryx faciata

Afternoon

12-14

O

M&F

Blue Quill

E & M

April 15

Paralepto-phlebia      adoptiva

Afternoon

18

S

A

Quill Gordon

E

April 15***

Epeorus pleruralis

Afternoon

14

B

F

Blue Quill

W

April 15

Paraleptophlebia  memorialis

Morning

18

S

A

Dark Quill Gordon

E & M

April 18

Ameletus ludens

Afternoon

12

S, O

M&F

Dark Olive Dun

E, M & L

April 20

Siphloplecton basale

Early afternoon

12

T

S & M

Little Black Caddis-C

E&M

April 20

Chimarra atterima

Afternoon

14

B

F

Male:  Red Quill       
Female:  Hendrickson

E&M

April 20

Ephemerella subvaria

Afternoon

14-16

B

A

Black Quill

E&M

April 22

Leptophlebia cupida

Afternoon

12

S

S

Grannom-C

E & M

April 22

Brachycentrus  fulliginosis

Afternoon

12-16

B

S &M

Grannom-C

E

April 22

Brachycentrus numerosis

Afternoon

12-14

B

S&M

Quill Gordon

W

April, May & June

Epeorus longimanus

Afternoon

14-16

B

M&F

 

Speckle-Winged Dun

W

May 1

Callibaetis americanus**

Morning &
 afternoon

14

T

S (prefers alkaline lakes)

Mother’s Day Caddis-C

W

May 1

Brachycentrus occidentalis

Afternoon

14-16

B

S&M

Light Stonefly-S

May 8            

Isoperla signata

Afternoon

12

O

F

Sulphur

E&M

May 8

Ephemerella invaria
(now includes rotunda)

Evening

15

T & M

M&F

Green Caddis-C

E&M

May  8

Rhyacophilia lobifera

Afternoon

14

B

F

Little Blue-Winged Olive Dun

W

May 10

Baetis brunneicolor

Afternoon

20

B

A

Western Green Drake

W

May 20

Drunella grandis

Morning

10-12

B

M

Little Blue-Winged Olive Dun

W

May 20

Baetis bicaudatus

Afternoon

20

B

A

Salmon Fly-S

W

May 20

Pteronarcys californica

Morning

8

O

F

Pale Morning Dun

W & A

May 20

Ephemerella excrucians
 (used to be inermis)

Morning,
afternoon,
or evening

16

T & M

A

Pale Evening Dun 

E&M

May 18

Ephemerella septentrionalis

Evening

14-16

B

F&M

Pale Morning Dun

W

May 20

Ephemerella dorothea infrequens

Morning

18

T & M

M

American March Brown

E&M

May 20

Maccaffertium vicarium

Afternoon
Spinner: Evening

12

T

F&M

Pale Evening Dun

E

May 20

Leucrocuta  aphrodite

Evening

16

T

F

Chocolate Dun

E&M

May 22

Eurylophella bicolor

Dun: Afternoon
Spinner: Evening

16-18

B

M

Spotted Sedge-C

E&M

May 23

Symphito-psyche slossanae

Afternoon

14

B

M&F

Light Cahill

E

May 25

Maccaffertium ithaca

Evening

14

T

M&F

Slate Drake

E&M

May 25**

Isonychia  bicolor

Evening

12

S

M&F

Female: Pink Cahill
Male: Light Cahill       

E&M

May 25**

Epeorus vitreus

Evening

14

B

M&F

Light Cahill

E&M

May 25

Stenacron
interpunctatum

Evening

12-14

T

M&F

Dark Green Drake

E&M

May 25

Litobrancha
recurvata

Dun:  Afternoon
Spinner: Evening

10

T

S

Brown Drake

E,M,W & L

May 24

Ephemera simulans 

Evening

10-12

T

S&M

Green Drake

E

May 24

Ephemera guttulata

Evening

8-10

T

S&M

Gray Drake

E&M

May 24

Siphlonurus
quebecensis

Dun:  Day
Spinner: Evening

12-14

S

S

Blue-Winged Olive Dun

E&M

May 25

Drunella lata (was cornuta)

Dun: Morning
Spinner: Evening

B

A

Blue Quill

E&M

May 26

Paraleptophlebia mollis

Morning &
 afternoon

18

S

A

Male: Chocolate Dun
Female: Olive Sulphur

E&M

May 30

Ephemerella   needhami

Dun: Morning
Spinner: Evening

16

T

M

Pale  Evening Dun

E&M

May 31

Ephemerella dorothea dorothea

Evening

18

T & M

M

 

Dark Blue Sedge-C

June 1

Psilotreta frontalis

Evening

14

B

Golden Stonefly-S

W

June 1

Calineuria californica

Morning

8

O

F

Blue-Winged Olive Dun

E&M

June 10

Drunella lata
(was cornutella)

Dun: Morning
Spinner: Evening

16

B

M

Yellow Drake

E & M

June 15

Ephemera varia

Evening

12

T

S

Green Drake

E, M & L

June 15

Hexagenia rigida

Evening

10

T

S

Pale Evening Dun

W

June 15

Heptagenia elegantula

Evening

14

T

S&M

Blue-Winged Olive Dun

W

June 15

Drunella flavilinea

Morning &
 evening

14

B

M&F

Blue-Winged Olive Dun

E&M

June 15

Danella simplex

Dun: Morning
Spinner: Evening

20

B

M

Light Cahill

E&M

June 15

Heptagenia
marginalis

Evening

12

T

M&F

Cream Cahill       

June 15

Maccaffertium  pulchellum

Evening

14

R

M&F

Dark brown Dun

W

June 15

Diphetor hageni

Morning &
 afternoon

20

B

M

Light Cahill

W

June 15

Cinygma dimicki

Evening

12

T

S & M

Pale Evening Dun

E&M

June 22

Leucrocuta hebe

Evening

16

R

M&F

Blue Quill                          

E&M

June 25

Paraleptophbia   guttata

Morning &
 afternoon

18

F

A

Golden Drake

E

June  25

Anthopota-manthus distinctus

Evening

12

B

S&M

Quill Gordon

W

June 25

Rhithrogena futilis & R. undulate

Morning &
 afternoon

12

T

F

Pink Lady

W

June 25

Epeorus albertae

Evening

12

B

M

 

Little Olive Dun (Trico)

E&M

July 1

Tricorythodes allectus (attratus)

Morning

24

S or B

S

Little Olive Dun (Trico)

E&M

July 1

Tricorythodes stygiatus

Morning

24

S or B

S

Gray Drake

W

July 1

Siphlonurus occidentalis

Afternoon

12

S

S

Little Olive Dun(Trico)

W

July 1

Tricorythodes minutus & others

Morning

24

S or B

S

Gray Fox

W

July 1

Heptagenia solitaria

Evening

14

T

F & M

Cream Cahill

August 1

Maccaffertiummodestum

Evening

14-16

T

M&F

White Fly

E&M

August 12

Ephoron leukon

Evening

14

T

M

Big Slate Drake

E&M

August 15

Hexagenia atrocaudata

Evening

8

T

S

White Fly

W

August 15

Ephoron album

Evening

14

T

M

Little Blue-Winged Olive Dun

E, M & W

September  1**

Baetis  tricaudatus

Dun: Afternoon
Spinner: Afternoon
& evening

20-22

B

A

Little Blue-Winged Olive Dun

E, M & W

September  1

Plauditus veteris

Afternoon

20

B

A

Slate Drake

E&M

September 1**

Isonychia bicolor

Afternoon &
 evening

14

S

F

Autumn Sedge

E&M

September 15

Neophyla species

Afternoon

12

B

F

* Later on inland waters
** More than one generation per year

*** Hatches can appear into June
**** Often the small generation is a size smaller
+ Appears in February in the Southwest (Arizona)

For more information on the hatches please purchase The Hatches Made Simple, Arizona Trout Streams,  Pennsylvania Trout Streams,  or Fishing Limestone Streams by clicking on “Books” at the bottom of this page.

Key to “Region found”

Key to “Where the nymph changes to a dun”

Type of water nymph inhabits

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Hatch Chart Charles R. Meck 2006

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