Popillia japonica vs scarabaean

Popillia japonica and scarabaean both are nouns.

Word	Noun	Adjective	Verb	Adverb
Popillia japonica	Yes	No	No	No
scarabaean	Yes	No	No	No

As nouns, scarabaean is a hypernym of Popillia japonica; that is, scarabaean is a word with a broader meaning than Popillia japonica:

Popillia japonica: small metallic green and brown beetle native to eastern Asia; serious plant pest in North America
scarabaean: any of numerous species of stout-bodied beetles having heads with horny spikes

Other hypernyms of Popillia japonica include scarabaeid, scarabaeid beetle.

Popillia japonica (noun)	scarabaean (noun)
small metallic green and brown beetle native to eastern Asia; serious plant pest in North America	any of numerous species of stout-bodied beetles having heads with horny spikes