Ommatidia serve the purpose of photoreception in:

Explanation

In cockroaches, the compound eyes are a pair of large, black, kidney shaped organs situated dorso-laterally on the head, one on either side. Their surface is marked by a large number of hexagonal areas, the facets. Each facet represents a visual unit named ommatidium. The eyes are the organs of sight (photoreception).In summary, ommatidia are specifically associated with the compound eyes of insects, such as cockroaches, for visual perception.