The shell is sinistral, ovate-conic, thin but strong, nearly smooth, brilliantly glossy. The shell has 5.5 whorls. The embryonic whorls are burnt sienna brown (weathering to whitish in adult shells), or sometimes there is a light median zone. The last whorl has either a uniform blackish chestnut, or a chestnut peripheral band and baso-columellar patch on a yellow ground, or like the last but with a green band midway between periphery and suture, or with sutural and peripheral bands and a baso-columellar patch of yellow on a chestnut ground. There are also a few specimens more or less intermediate between these patterns.
The aperture is moderately oblique, and colored white or faintly lilac within. The peristome is acute, and slightly or not thickened within. The columellar fold is strong, and is colored purple or white.
The height of the shell is 17.0 mm. The width of the shell is 11.0 mm.
- Hadfield M. & Hadway L. (1996). "Achatinella lila". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 11 January 2014.
- Gardin S., U.S. Army Garrison-Hawaii Public Affairs. (23 June 2008) Oahu's jewels of the forest fight for survival. accessed 27 October 2009.
- U.S. Fish and Wildlife Service. (1992) Endangered Species Recovery Plan for the O’ahu Tree Snails of the Genus Achatinella. U.S. Fish and Wildlife Service, Portland, Oregon, 64 pp. + 64 pp. of appendices + 5 figures. PDF
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