order Diptera vs dipterous insect

order Diptera and dipterous insect both are nouns.

Word	Noun	Adjective	Verb	Adverb
order Diptera	Yes	No	No	No
dipterous insect	Yes	No	No	No

order Diptera (noun)	dipterous insect (noun)
a large order of insects having a single pair of wings and sucking or piercing mouths; includes true flies and mosquitoes and gnats and crane flies	insects having usually a single pair of functional wings (anterior pair) with the posterior pair reduced to small knobbed structures and mouth parts adapted for sucking or lapping or piercing