Samia cynthia vs giant silkworm

Samia cynthia and giant silkworm both are nouns.

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

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

Samia cynthia: large green silkworm of the cynthia moth
giant silkworm: larva of a saturniid moth; spins a large amount of strong silk in constructing its cocoon

Other hypernyms of Samia cynthia include silkworm, wild wilkworm.

Samia cynthia (noun)	giant silkworm (noun)
large Asiatic moth introduced into the United States; larvae feed on the ailanthus	larva of a saturniid moth; spins a large amount of strong silk in constructing its cocoon
large green silkworm of the cynthia moth