There are two families of cicadas, Cicadidae (most cicadas) and Tettigarctidae (only two species). The two species in the Tettigarctidae family are Tettigarcta crinita, of southern Australia, and Tettigarcta tomentosa, of Tasmania. Cicadas of the family Tettigarctidae have ancestral morphology, similar to fossilized cicadas1. They are known for their hairy appearance.
Here are some morphological differences between the two cicada families:
| family | Tettigarcta | Cicadidae |
|---|---|---|
| Tymbal (Makes the cicada’s noise) | poorly developed in both sexes | well developmed in males |
| Tympana (listening apparatus) | no | yes |
| Pronotum (covers the dorsal area of the thorax) | expands over mesonotum | ends at pronotal collar |
| Pronotal collar (separates pronotum from mesonotum) | no | yes |
| Cruciform elevation (an X-shaped structure on mesonotum) | no | yes |
1See Allen F. Sanborn’s document Overview of Cicada Morphology for more information.
Here’s a photo of the Tettigarcta tomentosa from different angles (click the image for a closer view):
