Catocala coccinata, the scarlet underwing, is a moth of the family Erebidae. The species was first described by Augustus Radcliffe Grote in 1872. It is found in southern Canada and the eastern United States, following river valleys onto the Great Plains and down to Florida.

The wingspan is 57–70 mm. Adults are on wing from June to September depending on the location.

The larvae feed on Quercus species, including Quercus macrocarpa.

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