Lepidoptera vs class Insecta

Lepidoptera and class Insecta both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lepidoptera	Yes	No	No	No
class Insecta	Yes	No	No	No

Lepidoptera (noun)	class Insecta (noun)
moths and butterflies	insects; about five-sixths of all known animal species