The holotype of the enigmatic Philippine snake,Lycodon tessellatusJan 1863, not examined by any snake taxonomist after its original and supplementary descriptions in the middle-late 19th century, was located in the collection of the Naturhistorischen Museums in Vienna. Examination of this specimen refuted the undivided state of its nasal, which has long been believed to be an important diagnostic character of the species. A revised definition ofL. tessellatusis given together with a detailed description of the holotype. The species most resemblesL. aulicus(Linnaeus 1758), from which it differs in having three series of prominent alternating black spots on the dorsum in at least anterior part of the body. A key to Philippine species ofLycodonBoie 1826 is also revised accordingly.