maxillary palpus vs mouthpart

maxillary palpus and mouthpart both are nouns.

Word	Noun	Adjective	Verb	Adverb
maxillary palpus	Yes	No	No	No
mouthpart	Yes	No	No	No

As nouns, mouthpart is a hypernym of maxillary palpus; that is, mouthpart is a word with a broader meaning than maxillary palpus:

maxillary palpus: A maxillary palpus is a small several-segmented process on the outer aspect of each maxilla of an insect that is believed to have a sensory function.
mouthpart: any part of the mouth of an insect or other arthropod especially one adapted to a specific way of feeding

Other hypernyms of maxillary palpus include appendage, outgrowth, process.

maxillary palpus (noun)	mouthpart (noun)
A maxillary palpus is a small several-segmented process on the outer aspect of each maxilla of an insect that is believed to have a sensory function.	any part of the mouth of an insect or other arthropod especially one adapted to a specific way of feeding