silkworm moth vs saturniid moth

silkworm moth and saturniid moth both are nouns.

Word	Noun	Adjective	Verb	Adverb
silkworm moth	Yes	No	No	No
saturniid moth	Yes	No	No	No

As nouns, saturniid moth is a hypernym of silkworm moth; that is, saturniid moth is a word with a broader meaning than silkworm moth:

silkworm moth: any silkworm moth of the family Saturniidae
saturniid moth: large brightly colored and usually tropical moth; larvae spin silken cocoons

Other hypernyms of silkworm moth include saturniid.

silkworm moth (noun)	saturniid moth (noun)
moderate-sized Asiatic moth whose larvae feed on mulberry leaves and produce silk	large brightly colored and usually tropical moth; larvae spin silken cocoons
any silkworm moth of the family Saturniidae