Head Structure of the Psocid Psococerastis nubila (ENDERLEIN) (Psocoptera, Psocidae)

Head structure of Psococerastis nubila (ENDERLEIN) (Psocoptera, Psocidae) is described, with special reference to the musculature of the mandibles and maxillae. The cranium bears the frontogenal, epistomal, subgenal and postoccipital sutures, and Y-shaped ecdysial cleavage line, but the occipital suture is absent. The mouthparts are hypognathous and a typical biting type, and the mandible is similar to those of orthopteroid insects provided with a molar area, muscles (21), (23), (25) and (26). The maxilla is composed of the stipes, lacinia, four segmented maxillary palpus.