eye fly, common name for a group of small flies of the family Chloropidae. Eye flies are common in parts of California and in the S United States. They inhabit grasslands and meadows and breed mainly on decaying matter and excrement. Eye flies are attracted to animal secretions such as are found in the eyes, mouth, and open wounds. Some are thought to carry diseases such as conjunctivitis; West Indian species may transmit yaws, a disease caused by a spirochete. Eye flies are classified in the phylum Arthropoda, class Insecta, order Diptera, family Chloropidae.