Are Cicadas Locusts? The short answer is NO. However, in the U.S.A. we’ve been calling cicadas “locusts” for hundreds of years.
People have seen referring to cicadas, particularly Periodical cicadas, as both flies and “locusts” since the 1600’s, when colonists first documented them.
Gene Kritsky’s book Periodical Cicadas: The Plague and the Puzzle provides a chronology and historical texts of people referring to cicadas as “locusts”. Consider this quote from Pehr Kalm from 1756:
By the Engishmen here they are called Locusts and by the Swedes living here they have gotten the name Grasshoppers. In Latin they could be called Cicada.
It makes some sense that Englishmen would call cicadas Locusts, and Swedes would call them Grasshoppers, because there was only one species of cicada in both England and Sweden. This cicada, Cicadetta montana montana, call is so high-pitched you need electronic assistance to hear it, so most people were not aware of its existence. So, when Englishmen and women encountered cicadas they likely thought “there are a lot of them, they’re big, I’m afraid they’re going to eat my carrots — these must be LOCUSTS”!
Cicadas are indeed not Locusts, Grasshoppers or Flies.
Take a look that the illustration of a true locust below. You’ll notice the true locusts have HUGE rear legs for hopping, long antennae, and relatively long bodies. True locusts chew the plants they consume, while Magicicadas suck fluids from trees.
For more instances of cicadas being confused with other types of insects, read the article These are not cicada insects!