louse fly vs dipterous insect

louse fly and dipterous insect both are nouns.

Word	Noun	Adjective	Verb	Adverb
louse fly	Yes	No	No	No
dipterous insect	Yes	No	No	No

As nouns, dipterous insect is a hypernym of louse fly; that is, dipterous insect is a word with a broader meaning than louse fly:

louse fly: bloodsucking dipterous fly parasitic on birds and mammals
dipterous insect: insects having usually a single pair of functional wings (anterior pair) with the posterior pair reduced to small knobbed structures and mouth parts adapted for sucking or lapping or piercing

Other hypernyms of louse fly include dipteran, dipteron, two-winged insects.

louse fly (noun)	dipterous insect (noun)
bloodsucking dipterous fly parasitic on birds and mammals	insects having usually a single pair of functional wings (anterior pair) with the posterior pair reduced to small knobbed structures and mouth parts adapted for sucking or lapping or piercing