These small eyes are simple, and are called ocelli.
Many insects have ocelli, indeed, some of the grasshoppers have these extra eyes on top of their head.
May says the grasshoppers are very astonishing insects.
You think you know all about them, and you are all the time finding out something new. You would not be apt to notice these little ocelli on the grasshopper's head, they are so small, and besides, some of the grasshoppers do not have them.
Yes, Mollie, it is the same with the crickets and katydids. Some species have ocelli, and some have not.
If you look full in the face of a cicada,
you can see the three little round ocelli between the compound eyes.
They show very plainly with a magnifying glass.
Indeed, it is difficult to explain what the ocelli are for.