TroutWindowEphemeroptera · Heptageniidae
March Brown
Larger mottled spring mayfly. Comes with Quill Gordons and Hendricksons in the April freestone mix.
Taxa: Maccaffertium vicarium (American March Brown)
Large spring duns + rising fish = an easy go call.
Life stages
Mayfly path. Clinger nymphs on rock; mottled brown duns.
When it matters in the Southern Apps (NC–VA)
April SE freestone prior alongside Hendrickson and Quill Gordon.
Matching artificials & techniques
Mimic the stage the fish are eating — size and silhouette first. Patterns are common SE shop language, not a brand list.
March Brown nymph, Hare’s Ear (#10–14)
Rocky water, full-depth drifts.
March Brown dry, Adams variants
Bigger silhouette than BWO — don’t undersize.
Sources: Maccaffertium vicarium standard ID in eastern fly fishing; SE April calendar. Stage photos: Coming soon (Epeorus stand-ins removed — wrong genus). Regional note: Taxonomy and stage language follow standard aquatic entomology (Ephemeroptera / Trichoptera / Plecoptera / Chironomidae). SE timing is a regional prior from the hatch calendar — confirm with thermometer, seine, and local shop/agency charts.
SE hatch calendar All bugs Life-cycle basics
More in the guide: BWO · Midges · Caddis · October Caddis · Sulphurs · Tricos