What do Hexagenia limbataEphemerella dorothea, and Isonychia all have in common?  They are all BUGS!  Fly fishing is all about putting an imitation of a natural food source in the face of a fish, and many times that means insects.  The following hatch chart helps you make sense of the funny scientific names associated with the insects we try so hard to imitate.  Common names, usual seasons and peak emergences are all included for your reference. Highlighted rows indicate major hatches. Peak hatch periods are indicated in red.

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SizeCommon Name
Scientific Name
18/20 Tiny Early Winter Black Stonefly
Allocapnia granulata OR vivipara
16/20 Tiny Late Winter Black Stonefly
Nemouridae & Leuctridae
10/14 Early Black Stonefly
Taeniopteryx nivalis
12/14 Early Brown Stonefly
Brachyptera fasciata
18/20 Blue Wing Olive Mayfly
Baetis vagans
16/18 Slate Wing Mahogany Mayfly
Paraleptophlebia adoptiva
12/14 Dark Hendrickson Mayfly
Ephemerella subvaria
16/18 Little Black Caddis
Chimarra aterrima
12/14 Borcher's Drake Mayfly
Leptophlebia cupida
14/16 Grannon Caddis
Brachycentrus americanus
2/8 Midwestern Salmon Fly Stonefly
Pteronarcys dorsata
10/18 Green Rock Worm Caddis
Rhyacophilidae fenestra
8/14 Medium Brown Stonefly
Perlodidae isogenus & isoperla
10/14 Great Speckled Olive Mayfly
Siphloplecton basale
14/20 Net Building Caddis
Hydropsche bronta & simulans
16/18 Sulphur Dun Mayfly
Ephemerella dorothea
14/18 Little Yellow & Little Green Stonefly
Alloperla caudata & imbecilla
14/16 White Miller Caddis
20/22 Blue Wing Olive Mayfly
Baetis cingulatus
14/16 True Hendrickson Mayfly
Ephemerella invaria
14/16 Light Hendrickson Mayfly
Ephemerella rotunda
10/12 American March Brown Mayfly
Stenonema vicarium
12/14 Sand Drake Mayfly
Stenonema fuscum
12/14 Early Gray Drake Mayfly
Siphlonurus rapidus
10/12 Brown Drake Mayfly
Ephemera simulans
8/10 Great Orange Sedge Caddis
Phryganlidae ptilostomis
8/12 Green Oak Worm | Greenie Worm Caterpillar
20/28 Midges
10/12 Mahogany Dun Mayfly
Isonychia sadleri
6/8 Great Olive Winged Drake Mayfly
Hexagenia limbata
10/12 White Gloved Howdy Mayfly
Isonycha bicolor
12/14 Light Cahill Mayfly
Stenonema canadense
10/12 Late Gray Drake Mayfly
Sephlonurus alternatus
10/12 Golden Drake Mayfly
Ephemera varia
6/8 Big Golden Stonefly
Paragentina media
14/18 Slate Winged Olive Mayfly
Ephemerella lata
22/24 Tiny Blue Winged Olive Mayfly
Pseudocloen anoka
18/20 Dark Slate Wing Olive Mayfly
Ephemerella simplex
8/24 Terrestrials
24/26 Tiny White Wing Black Mayfly
Tricorythodes stygiatus
16/18 Small Slate Mahogany Dun Mayfly
Paraleptophlebia debilis
18/20 Black Dancer Caddisfly
Mystocides sepulchralis
22/24 Little Medium Olive Mayfly
Baetis pygmalus
12/14 White Fly Mayfly
Ephoron album
14/16 Slate Wing Brown Mayfly
Baetis heimalis
4/16 Eggs