RESUMO
The nesting behavior of Centris (Hemisiella) vittata Lepeletier was studied in the Urbano Santos Cerrado in the northeast of Maranhão State, Brazil. To date, this species has only been studied in trap-nests. The nesting behavior of this species in a natural condition is recorded for the first time. Nesting occurred in preexisting holes in dead trunks of aroeira, Astronium myracrodruon (Anacardiaceae), at the end of the rainy season. The cells were constructed with a mixture of sand and oil. After finishing the nests, females used only oil to line the entrance wall. Two females collected sand at the same time to build their nests, and another one was seen collecting resources at Byrsonima sp. (Malpighiaceae). The pollen load of one bee was analyzed and was found to contain mainly Hymenaea courbaril (Leg-Caesalpiniaceae). Development from egg to adult took about 60 days. Protandry was observed, being males smaller than females. The nests were parasitized by Coleoptera and Diptera. However, the females only showed aggressive behavior against females of the same species or genus.