Ellychnia is a genus of fireflies.

First defined by Émile Blanchard in 1845, the genus contains 24 species,[1] which are widespread in the United States.

[2] Adults are black, with rose-colored marks on the pronotum;[3] sexual dimorphism is unknown.

[4] These beetles are active during the day, and have no light-producing organs as adults;[5] instead, they attract mates using chemical signals.

[6] The larvae of Ellychnia fireflies live in rotting logs.