Hormones modulate phonotactic behaviors of female crickets (Acheta domesticus). This project seeks to observe the changes in phonotactic behavior when anti-histamine is injected in the prothoracic ganglion. The anti-histamine used, pyrilamine, resulted in older, unselective females becoming more selective to the male calling songs. Females injected with saline (controls) remained unselective. The experiments with pyrilamine (anti-histamine) validates histamine's proposed role on phonotactic selectivity by enhancing inhibition of syllable period selective neural circuits in the prothoracic ganglion.