Abstract
Two new species of Anagyrus Howard (Hymenoptera: Encyrtidae) are described from Argentina, A. cachamai Triapitsyn, Logarzo & Aguirre sp. n. (Catamarca, Córdoba, Salta and Tucumán Provinces) and A. quilmes Triapitsyn, Logarzo & Aguirre sp. n. (Catamarca, Salta and Tucumán). Both new species are parasitoids of Hypogeococcus spp. (Hemiptera: Pseudococcidae). Anagyrus cachamai is a parasitoid of H. pungens Granara de Willink on Alternanthera paronychioides, A. pungens and Gomphrena sp. (Amaranthaceae), and also of a Hypogeococcus sp. on Cleistocactus baumannii and Hypogeococcus sp. on C. smaragdiflorus (Cactaceae). Anagyrus quilmes is a parasitoid of H. pungens on A. paronychioides, A. pungens and Gomphrena sp. Other biological traits of the new species are also reported. These parasitoids may be of importance as potential candidate biological control agents against a Hypogeococcus sp., commonly called the Harrisia cactus mealybug and identified as H. pungens, but possibly not belonging to that species. This mealybug threatens the native cacti in some Caribbean islands and Florida, USA, and is devastating the native columnar cacti in Puerto Rico. Illustrations and taxonomic notes on the type specimens of some other, little known described species of Anagyrus from Argentina and Chile are provided, and a key to females of the 14 species of Anagyrus known from Argentina is given. Anagyrus nigriceps (De Santis) syn. n. is synonymized under A. bellator (De Santis). Lectotypes are designated for Paranusia bifasciata Brèthes, Philoponectroma pectinatum Brèthes, and Protanagyrus aciculatus Blanchard.