May bug vs Melolontha melolontha

May bug and Melolontha melolontha both are nouns.

Word	Noun	Adjective	Verb	Adverb
May bug	Yes	No	No	No
Melolontha melolontha	Yes	No	No	No

As nouns, May bug and Melolontha melolontha are synonyms defined as:

May bug and Melolontha melolontha: any of various large European beetles destructive to vegetation as both larvae and adult

Other synonyms of May bug include cockchafer, May beetle.

May bug (noun)	Melolontha melolontha (noun)
any of various large European beetles destructive to vegetation as both larvae and adult	any of various large European beetles destructive to vegetation as both larvae and adult
any of various large usually brown North American leaf-eating beetles common in late spring; the larvae feed on roots of grasses etc.