The tone of the chirp is related to the structure of the wings and how far apart the wrinkles of the file are. The frequency of the chirping varies according to temperature. It is possible to get a rough idea of the outside temperature in degrees Fahrenheit by counting the number of chirps in 15 seconds and adding 37. They consist of openings in the exoskeleton that lead into chambers inside the leg. By facing one way or the other, the cricket can tell which direction a sound is coming from.
Crickets make several different chirps.
The loud monotonous one we hear outside in the evening serves to attract a female. Another is made when a male knows a female is near and is softer and quicker. Yet another is made when two males encounter each other. The careful listener can pick out these individual dramas by listening for the different songs. After mating the female will look for a place to lay her eggs.