I propose to study courtship in periodical cicadas to determine how the various behavior patterns and songs of the males affect the females. All of the experiments must necessarily be done in the field, in or near the emergence areas. These will entail isolation of males and females with different amounts of sexual experience, use of auditory and visual models to artificially stimulate the females, and detailed comparative observations of courtship in monospecific and multispecific situations. We will also search for physiological correlates of the females' typical responses. A few preliminary experiments with female Magicicada septendecim and M. cassini suggested that the auditory sensitivity of these animals may be dependent on time of day and on frequency and repetition rate parameters of the stimulating sound. The peak activity times of these two species are different, and the songs of the males differ in both pulse repetition rate and frequency within pulses. I propose to investigate the auditory neurophysiology of the females, beginning with peripheral nerves and venturing into the central nervous system as it appears necessary and feasible.