mealy bug vs coccid insect

mealy bug and coccid insect both are nouns.

Word	Noun	Adjective	Verb	Adverb
mealy bug	Yes	No	No	No
coccid insect	Yes	No	No	No

As nouns, coccid insect is a hypernym of mealy bug; that is, coccid insect is a word with a broader meaning than mealy bug:

mealy bug: scalelike plant-eating insect coated with a powdery waxy secretion; destructive especially of fruit trees
coccid insect: scale insects and mealybugs

mealy bug (noun)	coccid insect (noun)
scalelike plant-eating insect coated with a powdery waxy secretion; destructive especially of fruit trees	scale insects and mealybugs