Development, oviposition, and mortality rates for Banks grass mite,Oligonychus pratensis(Banks) feeding on blue grama grass,Bouteloua gracitis(H.B.K.) Griffiths, were measured at constant temperatures of 19, 25, and 31°C. Complete life tables were computed from these data for each of the three temperatures. Developmental, survival, and ovipositional curves are given in both tabular and graphical form. It is apparent that the optimum temperature forO. pratensisis greater than 31°C. Population growth rate forO. pratensisfeeding on blue grama was similar to that previously reported for populations feeding on sorghum and barley.