Three new species of the genus Neuquenaphis (Hemiptera, Aphididae, Spicaphidinae) from southernmost South America.

Three new species of Neuquenaphis Blanchard are described from aphids collected in southernmost South America on several species of Nothofagus, southern beeches: Neuquenaphis blackmani Nieto Nafría and Brown, sp. n. from apterous and alate viviparous females and alatoid nymphs collected on Nothofagus dombeyi in Los Lagos and Los Ríos regions (Chile) and on Nothofagus nitida in Los Ríos region, Neuquenaphis aurata Mier Durante and von Dohlen, sp. n. from apterous and alate viviparous females collected on Nothofagus betuloides in Magallanes region (Chile) and Tierra del Fuego province (Argentina), and Neuquenaphis ramireziNieto Nafría and Ortego, sp. n. from apterous viviparous females collected on Nothofagus pumilio and N. antarctica in Tierra del Fuego province (Argentina) and La Araucanía, Aysén and Magallanes regions (Chile). Sequences of the mitochondrial COI "barcode" region and the tRNAleu-COII locus support the distinction of these new species from described Neuquenaphis species. Morphological characteristics that differentiate the new species from already described species of the genus are discussed. Partial identification keys for known apterous and alate viviparous females of Neuquenaphis species are presented on the basis of those established by Quednau (2010).