Bornean moths in the noctuid subfamily Catocalinae are described. The Catocalinae are treated in a broad sense, including also the old concept of the Ophiderinae, but this assemblage is probably paraphyletic as discussed in an introductory review of the classification and the characters of all stages that may be relevant. As a contribution to the development of a better classification of the group, the species are divided amongst 18 tribes, 4 further groups of genera that may be monophyletic, and 6 miscellaneous sequences of genera. The first 12 of these groupings are suggested to offer a more restricted, clearly defined and possibly monophyletic concept of the Catocalinae. Two new tribes outside this concept are proposed, the Sypnini and Anobini.
The treatment covers 591 species distributed over 222 genera. For each species, a diagnosis and the geographical range are given and, where known, details of habitat preference and biology. Summary lists are provided of the new taxa described (2 tribes, 4 genera, 99 species and 1 subspecies) as well as of numerous other taxonomic changes. A checklist of all species summarises the fauna.