Contributions to the wild bee fauna in Argentina (Hymenoptera: Anthophila) Author Alvarez, Leopoldo Jesús Author Ramello, Pablo José Author Avalos, Adan Alberto Author Almada, Valentín Author Aguirre, Marina Soledad Author Torretta, Juan Pablo Author Lucia, Mariano text Papéis Avulsos de Zoologia 2024 2024-02-05 64 1 13 https://www.revistas.usp.br/paz/article/view/215513 journal article 10.11606/1807-0205/2024.64.006 1807-0205 10943066 Genus Callonychium Brèthes Callonychium is a South American genus of small black-and-yellow colored bees, occurring in Argentina , Brazil , Chile , and Paraguay ( Gonzalez & Engel, 2016 ; Ruz et al., 2008 ). It is divided into two subgenera: in Callonychium s. str. the axillae are acute and yellow, while species of Paranychium Toro have axilla rounded, depressed and black. Species of Callonychium s. str. are not revised and there are additional forms not yet described ( Michener, 2007 ).