Many attempts to establish introduced parasites in Canada failed though the climatic conditions at their release points were apparently similar to those of their native habitats (Thorpe, 1930; Bairdet al., 1947). It is known that many adults of hymenopterous parasites feed on flowers, aphid honeydew, host body fluids, and other substances (Jackson, 19 37; Thorpe and Caudle: 1938; Schneider, 1939; Györfi, 1945, 1951; Zoebelein, 1956). This brings up the possibility that nourishment from one or more of the above sources is necessary for surviial and reproduction, and that some of the failures may have been because of the absence or scarcity of suitable adult food (Clausen. 1956). At present data on the food preferences of adult hymenopterous parasites are scarce. Except for a few field and laboratory observations, there are no experiments that demonstrate distinct preferences for one food over another. The results of the experiments described in the present paper demonstrate that adults of the species studied have preferences for some flowers and food substances tested.