Aulocara elliotti nymphs were raised from the first nymphal stage to the final instar on the leaves of crested wheat grass and western wheatgrass. The average efficiency of Conversion of Ingested Food to Body Substance (E.C.Ia of the male grass-hoppers fed on crested wheatgrass was found to be 8.50 percent compared to J 33% for those fed on western wheatgrass. The highest, 9A2 percent, occurred among the females fed on crested wheatgrass. During this period the Efficiency of Conversion of Digested Food to Body substance (E.C.D.) of the male grasshoppers was 22.52 percent on crested wheatgrass and 28.75 percent on western wheatgrass. The highest, 29.43 percent, occurred among the females fed on crested wheatgrass. In general the E.C.D. increased gradually during successive nymphal stages.