Populations of Hasora anura of Taiwan possess morphological characters and larval host usage which differ from those of conspecific populations in continental Asia. They are considered to represent a new subspecies endemic to Taiwan. This new subspecies is characterized by 1) an ocherous ground color on the wing undersides; 2) creamy-yellow markings on the hindwing undersides; 3) a valva rapidly narrowing distally; and 4) arms of the uncus close at the base. It is monophagous as a larva, feeding on Ormosia formosana (Fabaceae), in contrast to the broader host range of the continental populations, which utilize both Ormosia and Milletia (Fabaceae) as larval hosts. Year-round observations of the occurrence of immatures of this new subspecies and documentation in literature records suggest that it is a univoltine species, in which the occurrence of immatures is synchronized with the annual budding of its host; it probably overwinters as an adult.