The sexual response of male Schizocosa crassipalpis (Emerton), S. avida (Walckenaer), Pardosa moesta Banks, and P. saxatilis (Hentz) to filter paper discs previously exposed to females was studied in the laboratory. Evidence indicates that the females secrete a nonvolatile substance which the males receive through contact chemoreception and which excites them sexually. Attempts to demonstrate an olfactory cue in the sexual response were unsuccessful. The substance was found to be species specific except in S. crassipalpis. It was produced by adult females regardless of age or mating history. Male response was similarly not affected. The substance was active for about 4 weeks. It was labile to treatment with ether or benzene and could not be extracted with either solvent. The sites of its secretion and perception have not been ascertained.