Key to Subfamilies,

Tympanal coverings present.

Orifices of tympanum entirely concealed by tympanal coverings ......... Subfamily Cicadinae.

Orifices of tympanum more or less exposed, tympanal coverings imperfect ..... Subfamily, Gaeaninae .

Tympanal coverings absent, tympanal orifices completely exposed. Subfamily Tibicininae .