alula vs calypter

alula and calypter both are nouns.

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

As nouns, alula and calypter are synonyms defined as:

alula and calypter: scalelike structure between the base of the wing and the halter of a two-winged fly

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