Comparative study of phonotactic reactions of females of 5 species of crickets to the calling song (CS) of conspecific males and different sound models in Y-maze experiments showed: 1. InGryllodinus kerkennensis the essential property of the signal is the continuity of the song (Fig 3). 2. InGryllus campestris andG. bimaculatus pulse rate and chirp duration are important, the former having narrow and the latter broad tuning of reaction to chirp duration (Fig. 4). 3. InSpecies 2 (see Methods) chirp rate and pulse duration determine the specific response of females (Figs. 5 and 6). 4. InMelanogryllus desertus the most important parameters are the mean pulse rate and the increase in amplitude of pulses within the chirps (Fig. 7). 6. The spectrum of the CS is not important for the process of recognition as far as it falls into the tuning curve of specialized low-frequency channel of the auditory system. High-frequency sounds outside the range of this channel are not effective even if they have the same amplitude modulation pattern as the CS.