The author studied the effects of introducing strange wasps into the nests of three orphan groups of wasps. The three groups comprised twelve nests of P. pallipes, one nest of P. annularis and one nest of P. variatus. "The wasps were taken when young from their own nests and placed on nests among others of their own or sometimes of different species. Among their own kind, they were always tolerated, sometimes treated so cordially as to be entirely ignored; sometimes friendly curiosity was displayed by the old occupants, expressed by a clash of antennae which served as a greeting, and then they were taken in as members of the family." All three species of Polistes manifested an "instinctive hatred" for adults of other species of Polistes. Some of the individuals, however, used "discriminatory discretion and individual decision in dealing with their problems." Certain modifications of the instinctive reactions were observed. (PsycINFO Database Record (c) 2006 APA, all rights reserved)