class Hexapoda vs Phasmatodea

class Hexapoda and Phasmatodea both are nouns.

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

class Hexapoda (noun)	Phasmatodea (noun)
insects; about five-sixths of all known animal species	in some classifications considered a suborder of Orthoptera: stick insects; leaf insects