In all the mandibulate insects, then, the epipharynx forms simply the under surface or pharyngeal lining of the clypeus and labrum, the surface being uniformly moderately convex, and corresponding in extent to that of the clypeus and labrum, posteriorly merging into the palatal wall of the pharynx; the armature of peculiar gathering-hairs sometimes spreading over its base, being continuous with those lining the mouth and beginning of the œsophagus. The suture separating the labrum from the clypeus does not involve the epipharynx, though since certain gustatory fields lie under the front edge of the clypeus, as well as labrum, one may in describing them refer to certain fields or groups of cups or pits as occupying a labral or clypeal region or position. 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. The surface of the epipharynx, then, appears to be highly sensitive, and to afford the principal seat of the gustatory organs, which are described under the head of organs of taste. LITERATURE ON THE EPIPHARYNX =Réaumur.= Mémoires pour servir à l’histoire des insectes, v, 1740, p. 318, Pl. 28, Figs. 4, 7, 8, 9, 10, 11 l. =Kirby and Spence.= Intr. to entomology, iii, 1828, p. 457. =De Geer.= ii, 1778; v, 26, Fig. 11, M. =Kirby and Spence.= Pl. xii, Fig. 2 K. =Latreille.= Organisation extérieure des insectes, p. 184. (Quoted from Kirby and Spence.) =Savigny.= Mémoires sur les animaux sans vertèbres. Partie I^{re}, 1816, p. 12. =Walter, Alfred.= Beiträge zur Morphologie der Schmetterlinge. Erster Theil. Zur Morphologie des Schmetterlingsmundtheile. (Jena. Zeits., xviii, 1885, p. 752.) =Cheshire, F. R.= Bees and bee-keeping, i, London, 1886, p. 93.