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.
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.
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.
These are very rarely called March Browns.
This elegant species may produce fishable hatches.