A new ennomine species (Geometridae: Ennominae: Macariini) is described from northern Chile: Macaria mirthae sp. nov. Morphology of male and female genitalia of M. mirthae indicates close relationship to Macaria abydata Guenée, 1858. The latter species is widely distributed in the Neotropical and Indo-Pacific regions. Both species can be easily distinguished on the basis of habitus features and male and female genitalia. Larval stages of the new species M. mirthae are associated with Acacia macracantha Humb et Bonpl ex Willd., Prosopis tamarugo Phil. and Geoffroea decorticans (Gill ex Hook et Arn.) Burkart (Fabaceae) in the north of Chile.
Taxonomy; Macaria abydata; Acacia macracantha; Prosopis tamarugo; Geoffroea decorticans
