Cicada

fyi
Most members of the Genus Tibicen possess a well developed "Z-like" infuscation. This heavily infuscated (i.e. smoky black-grey) "Z" visible towards the ends of the forewings and typical of most Tibicen species may be poorly developed in a few species with only the cross veins being evident (i.e. The radial and radiomedial cross veins of tegmina, forewing, NOT heavily infuscated or darkened in Diceroprocta viridifascia.).

Compare with T. linnei here:
http://bugguide.net/node/view/32143

Seaside Cicada
There are 2 described races or subspecies in Florida

The "Atlantic form"
http://bugguide.net/node/view/26409
The "Gulf form"
http://bugguide.net/node/view/687308

Remember where you found it, you wont see another for about 15 years.