The pigment cells line the outside of each ommatidium.

One major reason for the dispute between classifications is the possible evolution of the ommatidium in the eyes.

Each such unit is called ommatidium, several are called ommatidia.

The different environments, predators, etc. probably led to the adaptation of ommatidium structures within this family.

The outer part of the ommatidium is overlaid with a transparent cornea.

In that of most daytime insects, each ommatidium is optically separated from its neighbours.

Each ommatidium feeds into a single nerve fiber.

The cornea and pseudocone form the outer 10% of the length of the ommatidium.

This has required the rewiring of the eye such that each ommatidium now has seven axons leading from it.

Each ommatidium is innervated by one axon and thus provides the brain with one picture element.

These "R cells" tightly pack the ommatidium.

The butterfly eye is similar to the average insect eye in that it is composed of numerous ommatidium.

Each 'ommatidium' (singular) is an individual 'eye unit'.

Ommatidium of the exocone type.

The drosophila ommatidium contains 8 distinct retinula or R cells, each of which has a different spectral sensitivity.

The R7 photo receptor, located in each of several ommatidium in the fly's compound eye, is used to detect ultraviolet light.

H1 exhibits a response to the stimulation of a single ommatidium, and can discriminate between translational motion of 2-3˚ in the visual field.

A compound eye may consist of thousands of individual photoreceptor units or ommatidia (ommatidium, singular).

An ommatidium contains a cluster of photoreceptor cells surrounded by support cells and pigment cells.

The portion of the R cells at the central axis of the ommatidium collectively form a light guide, a transparent tube, called the rhabdom.

Sclerites that should correspond to rhabdoms in 'eye theory' are interstitial to the hexagons, not at centre as would be expected for individual ommatidium.

Each butterfly ommatidium contains nine photoreceptors with generally each photoreceptor utilizing a single visual pigment.

For example the more advanced and numerous the ommatidium the more present the larger the ability of the insect to escape and elude predators.

The pigments which optically separate one ommatidium from another are withdrawn at night so that each rhabdom can receive light from many facets.

Each ommatidium contains 8 photoreceptor cells (R1-8), support cells, pigment cells, and a cornea.