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March Browns

Like most common names, "March Brown" can refer to more than one taxon. They're previewed below, along with 6 specimens. For more detail click through to the scientific names.

Mayfly Species Maccaffertium vicarium

These are pretty much always called March Browns.
In the East and Midwest this is one of the most important hatches of the Spring. They are large flies which emerge sporadically, making for long days of good fishing.

This species contains the two classic Eastern hatches formerly known as Stenonema vicarium and Stenonema fuscum, the "March Brown" and "Gray Fox." Entomologists have discovered that these mayflies belong to the same species, but they still display differences in appearance which the trout notice easily. Anglers should be prepared to imitate both types.
Maccaffertium vicarium (March Brown) Mayfly NymphMaccaffertium vicarium (March Brown) Mayfly Nymph View 5 Pictures
Collected April 19, 2006 from in
Added to Troutnut.com by on April 21, 2006
Male Maccaffertium vicarium (March Brown) Mayfly DunMale Maccaffertium vicarium (March Brown) Mayfly Dun View 10 PicturesI collected this mayfly on the same trip as a female of the same species. After these photos it molted into a spinner. This is the form of Maccaffertium vicarium which anglers call the "Gray Fox."
Collected May 28, 2005 from in
Added to Troutnut.com by on May 24, 2006
Female Maccaffertium vicarium (March Brown) Mayfly SpinnerFemale Maccaffertium vicarium (March Brown) Mayfly Spinner View 7 PicturesI collected this mayfly on the same trip as a male of the same species. They are Maccaffertium vicarium mayflies of the type formerly known as Stenonema fuscom, the "Gray Fox."
Collected May 28, 2005 from in
Added to Troutnut.com by on May 24, 2006

Mayfly Species Ephemera simulans

These are sometimes called March Browns.
The Brown Drakes are a favorite hatch of many in the Midwest, and they make a good showing on localized waters across the country. They are usually the first in a series of big drakes which bring large trout to the surface at twilight and into the early hours of the night.
Ephemera simulans (Brown Drake) Mayfly NymphEphemera simulans (Brown Drake) Mayfly Nymph View 10 Pictures
Collected January 31, 2004 from in
Added to Troutnut.com by on January 25, 2006
Male Ephemera simulans (Brown Drake) Mayfly SpinnerMale Ephemera simulans (Brown Drake) Mayfly Spinner View 7 Pictures
Collected June 2, 2005 from in
Added to Troutnut.com by on May 24, 2006

Mayfly Species Heptagenia pulla

These are very rarely called March Browns.
This elegant species may produce fishable hatches.
Heptagenia pulla (Golden Dun) Mayfly NymphHeptagenia pulla (Golden Dun) Mayfly Nymph View 8 PicturesLike most Alaskan mayflies, this one is tricky to identify to the species level. See the discussion section for an informative chat about this one's ID. The current leaning is to call it a fairly immature Heptagenia pulla nymph, but a case has been made for Heptagenia elegantula as well.
Collected July 10, 2011 from in
Added to Troutnut.com by on July 13, 2011
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