This text volume supplements Butterflies of the World, Part 29: Hesperiidae I. Hesperiidae of the Philippine Islands. It records 170 species and 49 additional subspecies of the butterfly family Hesperiidae found on the Philippine Islands. This is 19 more than the author's 1993 publication. Seven of these species were not only new to the Philippines, but new to science as well. More new records and new species can be expectec from the exploration of remote areas, and by the recognition of new taxa in genera with many similar species. Keys are given to all subfamilies, genera and species. If more than one subspecies of a species occurs in the Philippines, they are not keyed, but shortly diagnosed.