P. hustachei is very similar to P. bosqi and mainly differentiates because the eyes are more flat and oval, the pronotum is more smooth and with slender median sulcus, and elytral humeri are very reduced (Lanteri 1990b).
A key to species of Priocyphus is given in Lanteri (199b) and Lanteri & del Río (2016).
Unknown.
It is associated with vegetation typical of the Espinal biogeographic province, such as Acacia caven L. (= Vachellia caven) (Fabaceae).