American March Browns
Like most common names, "American March Brown" can refer to more than one taxon. They're previewed below, along with 5 specimens. For more detail click through to the scientific names.
These are often called American 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 very rarely called American March Browns.
is generally reported to be the largest North American species of mayfly in angler entomologies, though this understanding is being challenged by reports of Hexagenia limbata
that may exceed 40mm in some locales. Regardless, it is certainly the largest mayfly in the region of its distribution. Sometimes it appears together with species of Hexagenia
, but in other places it creates excellent action on its own.