Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† prŏboscis (-moscis, Sol. 24, 14; -muscis, Cassiod. Var. 10, 30), ĭdis, f., = προβοσκίς, a trunk, proboscis, a snout.
promuscis, ĭdis, a corrupt form for proboscis, a trunk, proboscis: elephas, promuscis, Not. Tir. p. 174.