Degenerated ocelli of cockroach is called is

Degenerated ocelli of cockroach is called is Fenestra.
The ocelli are paired circular areas one on each side of the eye, near the base of the antennae. Each area acts as a simple eye and is responsible for detecting light.
Ocelli or fenestrae of cockroach take part in perception of light. They help the cockroaches to detect food and other objects. Fenestrae are simple eyes.