Alcadia microstoma is a species of an operculate land snail, terrestrial gastropod mollusk in the family Helicinidae.

[1] (Original description) The shell is globose-conic and moderately thickened, with a brown coloration that shades off to a smoky white along the suture and the periphery of the body whorl.

It features rather light growth striae, interspersed with a few spiral series of punctures.

The shell has slightly fewer than five moderately convex whorls with a well-impressed suture.

The outer lip is sinuate, well-expanded, and reflected except at the extremities, with a slit that is rather wide but not very deep.