The genus Centris contains circa 250 species of large apid bees occurring in the Neotropical and Nearctic regions, from Kansas to Argentina. Most females of these bees possess adaptations for carrying floral oils rather than (or in addition to) pollen or nectar. They visit mainly plants of the family Malpighiaceae to collect oil, but also Plantaginaceae, Calceolariaceae, Krameriaceae and others. Recent studies have shown they are sister to the corbiculate bees, the most well-known and economically important group of bees