bed bug vs hemipteran

bed bug and hemipteran both are nouns.

Word	Noun	Adjective	Verb	Adverb
bed bug	Yes	No	No	No
hemipteran	Yes	No	No	No

As nouns, hemipteran is a hypernym of bed bug; that is, hemipteran is a word with a broader meaning than bed bug:

bed bug: bug of temperate regions that infests especially beds and feeds on human blood
hemipteran: insects with sucking mouthparts and forewings thickened and leathery at the base; usually show incomplete metamorphosis

Other hypernyms of bed bug include bug, hemipteron, hemipterous insect.

bed bug (noun)	hemipteran (noun)
bug of temperate regions that infests especially beds and feeds on human blood	insects with sucking mouthparts and forewings thickened and leathery at the base; usually show incomplete metamorphosis