The detailed text for this volume is published in Butterflies of the World, Supplement 15. It illustrates 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.
The plates usually show both males and females, and upperside and underside. In cases in which there was no Philippine material available for illustration, specimens from outside the Philippines have been used. All photographed specimens are in the collection of C.G. Treadaway ((to be depositied in Museum Senckenberg, Frankfurt/Main), except where stated otherwise. Among the illustrated specimens are 46 holotypes, 51 paratypes, four lectotypes and two paralectotypes.