Hymenoptera vs class Hexapoda

Hymenoptera and class Hexapoda both are nouns.

Word	Noun	Adjective	Verb	Adverb
Hymenoptera	Yes	No	No	No
class Hexapoda	Yes	No	No	No

Hymenoptera (noun)	class Hexapoda (noun)
an order of insects including: bees, wasps, ants, ichneumons, sawflies, gall wasps, etc.	insects; about five-sixths of all known animal species