Phthona is a genus of biting flies in the family of louse flies, Hippoboscidae. There are 3 known species. All are parasite of falconets of the genus Microhierax.
All species are found in South East Asia.
They found on birds of the genus Microhierax - species: collared falconet (M. caerulescens), Philippine falconet (M. erythrogenys) and the pied falconet (M. melanoleucus)