Recent interest in the phylogenetic relationships within the family Endomychidae and the association of the family with other Cerylonid Series families, particularly Coccinellidae, has resulted in a number of studies attempting to reconstruct the phylogeny of the family using both morphological and molecular data sources. However, these studies have yielded conflicting hypotheses about the monophyly of the family, reintroducing previous speculation that the family may be a heterogeneous assemblage of taxa rather than a natural group. The work presented herein constitutes significant progress in two different but complementary areas of systematic study on the family Endomychidae. The first part is a family-level phylogenetic analysis based on eight genes utilizing parsimony, likelihood and Bayesian techniques. The second part consists of a taxonomic revision of the genus Bystus and a comprehensive morphological study of one exemplar species, B. piceus. An updated, annotated checklist for the family and a review of the natural history of the family are also provided.