Ypresiosirex is an extinct genus of parasitic wasp in the horntail family Siricidae. The genus is solely known from a single Eocene fossil found in North America. At the time of its description the new genus was composed of a single species named Ypresiosirex orthosemos.
Species taxanomy provided by GBIF Secretariat (2022). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2023-06-13; License: CC BY 4.0