Mesothea is a monotypic moth genus in the family Geometridae described by Warren in 1901.

Its only species, Mesothea incertata, the day emerald or plain emerald, was first described by Walker in 1863.

[2] The MONA or Hodges number for Mesothea incertata is 7085.

[6] It has two subspecies: Data sources: i = ITIS,[2] c = Catalogue of Life,[3] g = GBIF,[4] b = Bugguide.net[5]

This Geometrinae-related article is a stub.