Popillia japonica vs scarabaeid

Popillia japonica and scarabaeid both are nouns.

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

As nouns, scarabaeid is a hypernym of Popillia japonica; that is, scarabaeid 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
scarabaeid: any of numerous species of stout-bodied beetles having heads with horny spikes

Other hypernyms of Popillia japonica include scarabaean, scarabaeid beetle.

Popillia japonica (noun)	scarabaeid (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