Foraging behavior was studied on a desert grassland site 40 km NNE of Las Cruces, New Mexico. The number of workers foraging decrease logarithmically with distance from colony when individual seeds were evenly distributed and varied directly with seed density. Some colonies of Pogonomyrmex rugosus exhibited group foraging while others did not. Foraging territories of individual colonies of P. rugosus were irregular in shape and overlapped considerably with foraging territories of adjacent colonies of P. rugosus.