alternative definition added over 14 years ago by Istvan Miko
Arise on the inner proximal surface of the frons, laterally to the origin of the anterior labral retractor, but mesally to the posterior labral retractors. They insert on the distal part of the pharynx, just proximally to the morphological mouth; usually, two pairs are present.
Reference: Vilhelmsen, L. 1996. The preoral cavity of lower Hymenoptera (Insecta): comparative morphology and phylogenetic significance. Zoologica Scripta 25:143-170.
Cross reference:
None provided.