Hypopharyngeal: relating to the hypopharynx.
"Explanation of Terms Used in Entomology" by John. B. Smith
Just below this is the hypopharynx, the lateral margins of which are very thin.
"Insects and Diseases" by Rennie W. Doane
The same, hypopharynx, ventral aspect.
"Journal of Entomology and Zoology" by Horace Gunthorp
Folsom looks on the hypopharynx as a secondary development.
"Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4" by Various