Chlosyne janais, the crimson patch or janais patch, is a common New World butterfly found from Colombia north through Central America and Mexico to southern Texas, with occasional sightings in southeastern Mexico and northern Texas.

The ventral hindwings have a fragmented yellow proximal patch bordered by a thick postmedial band of red that does not reach the wing margins; maximum wingspan is 4.8–6.7 cm.

Adults inhabit the periphery of lowland tropical to subtropical forests, fields, and along streams, where they feed on flower nectar.

Reproduction is continuous in the tropics, whereas in temperate areas several broods are produced from July to November.

The caterpillars are grey white to green with several transverse rows of fleshly black spines; they feed primarily on acanthus shrubs, especially Anisacanthus wrightii and Odontonema callistachus (in Texas), upon which adult females lay their eggs.