W. Schultze, director of the Bureau of Science in Manila during the early part of the 20th century published in The Philippine Journal of Science his three part monograph on the Pachyrrhynchini:
A Monograph of the Pachyrrhynchid Group of the Brachyderinae Curculionidae: Part I The Genus Pachyrrhynchus Germar (A & B), 1923 & 1924
Part Ia consists of 28 species, 3 subspecies and 3 variations with 4 new descriptions.
Part 1b includes 52 species, 8 subspecies and 6 variations of which 4 are new to Science.
A Monograph of the Pachyrrhynchid Group of the Brachyderinae, Curculionidae: Part II The Genera Eupachyrrhynchus, Macrocyrtus, Eumacrocyrtus, Apocyrtus, Proapocyrtus, Pseudapocyrtus, Nothapocyrtus and Exnothapocyrtus, 1924
Part II treats 31 species and 2 variations of which 2 are new.
A Monograph of the Pachyrrhynchid Group of the Brachyderinae, Curculionidae: Part III The Genera Apocyrtidius Heller and Metapocyrtus Heller, 1925
Part III 176 species, 12 subspecies and 15 variations with 100 being new descriptions.
All in all, the three parts counts 287 species, 23 subspecies and 26 variations with 110 being new to Science. Between 1925 and 1934, there were additional new descriptions of Pachyrrnchini but beyond that, none.
- Taxonomic review of the Genus Metapocyrtus Heller (Coleoptera: Curculionidae: Entiminae) – YAP & GAPUD, 2007
- The fascinating Curculionid tribe Pachyrrhynchini
- Checklist of the Metapocyrtus Complex (Curculionidae: Entiminae: Pachyrrhynchini) of the Philippines – YAP, 2008
- Two new and important papers on the Pachyrrhynchine weevil beetle genus Metapocyrtus
- Hudepohl’s The Longhorn Beetles of the Philippines