The bee-plant community in a xeric ecosystem in northwestern Argentina was studied concerning diversity, relative abundance, floral preference and phenology. Fifty-seven bee species were recorded, 42.1% of them endemic to arid regions of southern South America, visiting flowers of 11 plant species. The most abundant bees were Canephorula apiformis (Friese, 1908), Isomalopsis niveata (Friese, 1908) and Melectoides bellus (Jorgensen, 1912). No strictly specialist bee was observed. Some aspects of bee-flowers associations and distribution patterns are discussed.

This species from the Mata Atlântica resembles Melipona lateralis Erichson, 1848 and M. seminigra Friese, 1903 from the Amazonian Region. It can be easily distinguished from the first and its nearest relalive, M. scutellarís Latreille, 1811 by having a more shining mesoscutum and from the second by the yellow facial markings.