The Swamp Metalmark (
Calephelis muticum) is a small butterfly in the family
Riodinidae. It has upper wings of a dull red-brown background color and two metallic rows outlining the outer margins. The underside is bright golden orange with black speckles. The wingspan is 0.9-1.2 inches (24-30 mm). Larvae are distinctive pale green caterpillars covered profusely with long white hairs and are found on the leaves of swamp thistle (
Cirsium muticum), the larval host plant. The swamp metalmark inhabits bogs, marshes, swamps and wet meadows. Populations have been found in southern Michigan, southern Wisconsin, Ohio, Missouri, and northern Arkansas, with isolated populations in central Kentucky and eastern Iowa. Populations have also been reported in northern and southern parts of Indiana; populations in southern Indiana occur in barrens where larval food plants are
Cirsium altissimum and possibly
Cirsium carolinianum. It produces one to two broods per year, with the adults appearing in late spring (south) and again in late summer (north and south). Despite the production of multiple broods, the swamp metalmark is almost never common and most records consist of only one or a few individuals. The destruction of the nation's mesic grasslands and graminoid wetlands over the past 200 years has greatly reduced suitable habitat for this and many other species.