''Neonympha mitchellii'' is an endangered species of

nymphalid The Nymphalidae are the largest family of butterflies, with more than 6,000 species distributed throughout most of the world. Belonging to the superfamily Papilionoidea, they are usually medium-sized to large butterflies. Most species have ...

butterfly of the eastern United States. There are two known subspecies:. *''N. m. mitchellii'', the

nominate subspecies In biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. ...

, commonly called Mitchell's satyr or Mitchell's marsh satyr, is found in

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

and

Indiana Indiana ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the s ...

. The species is presumably

extirpated Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. Local extinctions mark a chan ...

from former ranges in Ohio (last seen in the 1950s), New Jersey (last seen in 1988), and Wisconsin. *'' N. m. francisci'', commonly called Saint Francis' satyr, is found in a single

metapopulation A metapopulation consists of a group of spatially separated populations of the same species which interact at some level. The term metapopulation was coined by Richard Levins in 1969 to describe a model of population dynamics of insect pests in a ...

in a 10 × 10 km area of

Fort Bragg Fort Bragg (formerly Fort Liberty from 2023–2025) is a United States Army, U.S. Army Military base, military installation located in North Carolina. It ranks among the largest military bases in the world by population, with more than 52,000 m ...

in North Carolina. Recent discoveries since 1998 of populations in Alabama, Mississippi, and Virginia are being studied for taxonomic classification, and may be grouped with ''N. m. mitchellii'' or be described as new subspecies. All subspecies, including those newly discovered, are federally protected under the

Endangered Species Act The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of e ...

. Its larvae can feed upon the highly-invasive Japanese stilt grass ''

Microstegium vimineum ''Microstegium vimineum'', commonly known as Japanese stiltgrass, packing grass, or Nepalese browntop, is an annual grass that is common in a wide variety of habitats and is well adapted to low light levels. It has become an invasive species thr ...

'', so populations of this butterfly are potentially at risk from efforts to remove stilt grass. A butterfly of similar appearance, the Carolina satyr ('' Hermeuptychia sosybius''), is also able to feed upon stilt grass.

Description

Both subspecies are small brown butterflies with a wingspan rage of 34–44 mm. The upper surfaces of their wings are unmarked, while the undersides of the wings have rows of round, yellow-ringed eyespots. ''N. m. francisci'' is slightly darker, with more irregularly shaped eyespots. Their eggs are greenish white to cream, becoming tan as they age. The larvae's dark head can be seen a day or two before hatching. First

instar An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...

larvae, 3–4 mm long, have dark brown bilobed heads, while four subsequent instars, 6–12 mm long, have green bilobed heads, and green bodies with raised white ridges along the sides. The chrysalis is 10.5–15.5 mm long, suspended with the head down. It is a light lime green, with pale green or white speckling, and turns a medium brown about two days before

eclosion A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

References

{{Taxonbar, from=Q3021145 Butterflies of North America Neonympha Butterflies described in 1889 ESA endangered species Lepidoptera of the United States