arctiid vs tiger moth

arctiid and tiger moth both are nouns.

Word	Noun	Adjective	Verb	Adverb
arctiid	Yes	No	No	No
tiger moth	Yes	No	No	No

As nouns, tiger moth is a hyponym of arctiid; that is, tiger moth is a word with a more specific, narrower meaning than arctiid:

arctiid: stout-bodied broad-winged moth with conspicuously striped or spotted wings; larvae are hairy caterpillars
tiger moth: medium-sized moth with long richly colored and intricately patterned wings; larvae are called woolly bears

Other hyponyms of arctiid include Callimorpha jacobeae, cinnabar, cinnabar moth.

arctiid (noun)	tiger moth (noun)
stout-bodied broad-winged moth with conspicuously striped or spotted wings; larvae are hairy caterpillars	medium-sized moth with long richly colored and intricately patterned wings; larvae are called woolly bears