Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

ommatidium, ommatidia

Ommatidium of Machilis
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
No Taxon (Glossary)
No Taxon (O)
No Taxon ommatidium, ommatidia
Explanation of Names
From Greek ommation little eye, that from ommato to furnish with eyes, plus diminutive suffix -idion (1).
Identification
ommatidium noun, plural ommatidia - individual element(s) of an insect's compound eye (oculus). Each ommatidium consists of a lens, cone, rhabdom (photoreceptive structure), and pigment cells. The number is variable--from one in worker ants, to circa 2,000 in a dragonfly, and up to 9,000 in some insects. Each ommatidium is approximately 20 μm in diameter and 100 μm in length (1).
Print References
Gordh, entry for ommatidium (1)
Internet References
Wikipedia--Ommatidium
Works Cited
1.A Dictionary of Entomology
George Gordh, David H. Headrick. 2003. CABI Publishing.