Anal cells are rear components of the

insect wing Insect wings are adult outgrowths of the insect exoskeleton that enable insects to fly. They are found on the second and third thoracic segments (the mesothorax and metathorax), and the two pairs are often referred to as the forewings and hindwin ...

s, found for example in

Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

(flies). A cell, in the case of an insect wing, is the central area surrounded by veins. It can be closed by veins or open.

References

Insect anatomy {{insect-anatomy-stub