An examination of the type-specimens of Aedes (Stg.) simpsoni (Theobald), Ae. (Stg.) lilii (Theobald), Ae. (Stg.) bromeliae (Theobald) and other available material indicates that simpsoni is a species complex. A lectotype female for Aedes (Stegomyia) simpsoni (Theobald) is designated, fully described and illustrated. Diagnostic characters for recognizing simpsoni, lilii and bromeliae females are presented. Characters for separating the simpsoni complex from other Ethiopian Stegomyia are also given.