Alcadia macilenta is a species of an operculate land snail, terrestrial gastropod mollusk in the family Helicinidae.
(Original description) The shell is rather small and thin, subdiscoidal, and flattened beneath, with a pale brown coloration. The epidermis is extremely thin, microscopically hirsute, or chagrined. The spire is slightly elevated and convex, consisting of nearly 4ý whorls that are scarcely convex. The aperture is large, and the outer lip is thin, sharp, moderately expanded, and reflected, featuring a deep curved incision below the columella, similar to that of Alcadia brownii palliata <small>(C. B. Adams, 1849)</small>. The elongated columella is strongly margined on the inner side.
This species occurs in Jamaica.