lygaeid bug vs lygaeid

lygaeid bug and lygaeid both are nouns.

Word	Noun	Adjective	Verb	Adverb
lygaeid bug	Yes	No	No	No
lygaeid	Yes	No	No	No

As nouns, lygaeid bug and lygaeid are synonyms defined as:

lygaeid bug and lygaeid: a true bug: usually bright-colored; pest of cultivated crops and some fruit trees

lygaeid bug (noun)	lygaeid (noun)
a true bug: usually bright-colored; pest of cultivated crops and some fruit trees	a true bug: usually bright-colored; pest of cultivated crops and some fruit trees