A new Argentinean aphid species, Aphis mendocina, is described. It lives on the nati ve Urticaceae, Urtica mollis. Descriptions of apterous and alatae viviparous females, oviparous females, and males, which are apterous, are presented. An identifica tion key to the apterous viviparous females of Aphis species with large dorsal abdominal sclerotization recorded from South American is given.
