The stridulatory apparatus consists of a smooth vein on the fore wing and a keel with fine pegs on the inner side of the hind femur. The songs are very varied and characteristic. In most species there are differnt types of song, the principal ones being the calling song (to attract the female), rivalry song (when males meet) and courtship song (in pairing). It is sometimers very difficult to identofy the species, but studying the songs makes it much easier even in difficult cases. 
- . A Field Guide to the Grasshoppers and Crickets of Britain and Northern Europe. William Collins & Sons; 1988.