alula vs squama

alula and squama both are nouns.

Word	Noun	Adjective	Verb	Adverb
alula	Yes	No	No	No
squama	Yes	No	No	No

As nouns, squama is a hypernym of alula; that is, squama is a word with a broader meaning than alula:

alula: scalelike structure between the base of the wing and the halter of a two-winged fly
squama: a protective structure resembling a scale

alula (noun)	squama (noun)
tuft of small stiff feathers on the first digit of a bird's wing	a protective structure resembling a scale
scalelike structure between the base of the wing and the halter of a two-winged fly