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The lack of traces of a suture in the epipharynx corresponding to the labral suture above, suggests that the labrum does not represent a pair of coalesced appendages, and that it, with the clypeus, simply forms the solid cuticular roof of the mouth.

The only soft structures seen between the epipharynx and labrum, besides the nerves of special sense, are the elevator muscles of the labrum, and two tracheæ, one on each side.

The structure and armature of the epipharyngeal surface even besides the taste-pits, taste-cups and rods, is very varied, the setæ assuming very different shapes. There seem to be two primary forms of setæ, (1) the normal forms which arise from a definite cell; and (2) soft, flattened, often hooked hairs which are cylindrical towards the end, but arise from a broad triangular base, without any cell-wall. These are like the “gathering hairs” of Cheshire, situated on the bees’ and wasps’ tongue; they also line the walls of the pharynx and extend toward the œsophagus. They are also similar to the “hooked hairs” of Will. The first kind, or normal setæ, are either simply defensive, often guarding the sense-cups or sensory fields on which the sense-cups are situated, or they have a nerve extending to them and are simply tactile in function.