Samia cynthia vs silkworm moth

Samia cynthia and silkworm moth both are nouns.

Word	Noun	Adjective	Verb	Adverb
Samia cynthia	Yes	No	No	No
silkworm moth	Yes	No	No	No

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

Samia cynthia: large Asiatic moth introduced into the United States; larvae feed on the ailanthus
silkworm moth: any silkworm moth of the family Saturniidae

Other hypernyms of Samia cynthia include giant silkworm moth.

Samia cynthia (noun)	silkworm moth (noun)
large Asiatic moth introduced into the United States; larvae feed on the ailanthus	moderate-sized Asiatic moth whose larvae feed on mulberry leaves and produce silk
large green silkworm of the cynthia moth	any silkworm moth of the family Saturniidae