Abstract New information is presented for bats and their ectoparasite insects from the Argentine Field and Weedlands Ecoregion. Bats of the families Molossidae, Phyllostomidae and Vespertilionidae containing ectoparasites belonging to families Polyctenidae (Hemiptera), Nycteribiidae and Streblidae (Diptera) were collected. Here is presented the first record of Hesperoctenes cartus Jordan, 1922 for Argentina. Basilia plaumanni Scott, 1940 and H. vicinus Jordan, 1922 are added to the province of Misiones and Paratrichobius longicrus (Miranda Ribeiro, 1907) is added to the province of Corrientes. Additionally, the distributions of some ectoparasite insects are extended and new host-ectoparasite associations are reported.

Based on specimens collected from bats of different families, we add new species and extend the known ecological distribution and host associations of insect ectoparasites of bats in Peru. New information is provided for the distribution of 26 species of parasites (25 Diptera and 1 Siphonaptera: Ischnopsyllidae). Four species (Neotrichobius ectophyllae, Strebla galindoi, Strebla paramirabilis and Myodopsylla wolffsohni wolffsohni) are new for Peru and 16 represent new records for the department of Loreto. Also, we found 17 new host-ectoparasite relationships. Of note, we found remarkable new association between Neotrichobius delicatus and bat species from the families Molossidae and Noctilionidae and a novel association between Paradyschiria parvula and a species of Vespertilionidae. Host-ectoparasite specificity was recorded with 14 species as monoxenous, three oligoxenous, seven pleioxenous and two polyxenous.