In 2014, Matthew Arey and Alex Grkovich described a new subspecies of Wood Nymph that occurs in the salt marshes in New England (type locality in Essex Co., MA). The rest of the eastern coastline hasn’t been surveyed for this critter yet, to my knowledge, so it’s possible that diligent observers in Delmarva could add this taxon to the region’s fauna.
The attached paper describes some morphological differences from better known taxa, but the big distinctions between the newly described Salt Marsh Wood Nymph and other Common Wood Nymph variants in New England are some very odd behavioral characteristics. We all know Common Wood Nymph from inland grasslands by its “bobbing” flight, as if on a yo-yo string that jerks it up and down in tall grass. The new subspecies, agawamensis, is characterized as having a direct, level flight instead; according to the authors, this butterfly is semi-communal, and spooking one of the butterflies sets the whole cluster/group in motion (a trait they seem to share with some tropical satyrids). Also unique to Salt Marsh Wood Nymph is the fact that it is an avid nectar feeder — it’s a rare sight indeed to find Common Wood Nymph on flowers, but apparently Salt Marsh regularly visits flowers. The timing of the brood is also somewhat offset from the flights of congeners.
Read the full paper here for more info: Arey & Grkovich 2014. Cercyonis pegala agawamensis (Satyridae): A new butterfly subspecies from the coastal salt marshes of the northeastern United States of America