Information on the nesting biology of the large, ground-nesting, communal eucerine Svastra (Epimelissodes) sabinensis sabinensis (Cockerell) from Arizona is added to a previous account (Rozen, 1983). Details of nest size, location, depth, and structure are reported. Mature oocytes dissected from females are illustrated and described. Further information on its cocoon is presented and interpreted with respect to how it functions. The postdefecating larva is described and compared with that of S. o. obliqua (Say), the only other Svastra larva described to date. The association of this bee with Triepeolus penicilliferus (Brues) is further confirmed with the recovery of an immature larva of this cleptoparasite from one of the nest cells.