order Ephemerida vs order Ephemeroptera

order Ephemerida and order Ephemeroptera both are nouns.

Word	Noun	Adjective	Verb	Adverb
order Ephemerida	Yes	No	No	No
order Ephemeroptera	Yes	No	No	No

As nouns, order Ephemerida and order Ephemeroptera are synonyms defined as:

order Ephemerida and order Ephemeroptera: the order of mayflies or shadflies (Ephemeroptera, Ephemerida)

Other synonyms of order Ephemerida include Ephemerida, Ephemeroptera.

order Ephemerida (noun)	order Ephemeroptera (noun)
the order of mayflies or shadflies (Ephemeroptera, Ephemerida)	the order of mayflies or shadflies (Ephemeroptera, Ephemerida)