Mid 19th century; earliest use found in Noah Webster (1758–1843), lexicographer. From classical Latin muscusmoss + -oid.
muscoid2
/ˈmʌskɔɪd/
Entomology
adjective
Relating to or designating dipteran flies of the section Schizophora (suborder Cyclorrhapha), especially of the superfamily Muscoidea which includes Muscidae and related families.
noun
A muscoid fly.
Origin
Early 20th century; earliest use found in Science. From scientific Latin Muscoidea, superfamily name from Musca + -oidea, suffix forming superfamily names.