Mesapamea fractilinea. Mesapamea fractilinea, comb. n., is superficially almost identical to Mesapamea secalis (Linnaeus) and occurs in the same four color morphs. However, M. fractilinea and M. arbora (Barnes & McDunnough, 1912), comb. n. form a group in North America with a much more modified and ornate male cucullus than found in the European species of the genus.