[Illustration: Fig. 7.—Trophi and their unfolding. _a_, labrum; _b_, epipharynx; _c_, pharynx; _d_, hypopharynx; _e_, mandible; _f_, maxillæ; _g_, maxillary palpi; _h_, mandible; _i_, cardium; _k_, labium; _l_, labial palpi; _m_, paraglossæ; _n_, tongue.] The _labrum_, or upper lip, is attached by joint to the apex of the _clypeus_; it has a vertical motion, and falls over the organs beneath it, in repose, when it is itself covered by the mandibles. It is usually transverse in form, but is sometimes perpendicular, especially in the artisan bees. It takes many forms, sometimes semilunar or linear, emarginate or entire, convex, concave, or flat, and is occasionally armed with one or two processes, like minute teeth projecting from its surface, but of what use these may be we do not know. In the female of _Halictus_, it has a slightly longitudinal appendage in the centre. It is usually horny, but is sometimes coriaceous or leathery. This labrum often yields good specific characters. The _pharynx_, or gullet, is a cavity immediately beneath the _epipharynx_, which articulates directly under the base of the labrum, and which closes the pharynx from above, and immediately beneath this cavity is another small appendage, almost triangular, which receives the food or honey from the canal conveying it from the tongue, or directly from the mandibles, when it is masticated, and helps it forward to the pharynx to be swallowed. The _epipharynx_ closes this orifice from above, the _labrum_ then laps over it and the articulation of the lingual apparatus, both which are further protected in repose by the mandibles closing over the labrum. This triple protection shows the importance nature attaches to these organs. The more direct portions of the lingual apparatus are the _labium_, or lower lip, which forms the main stem of the rest, and articulates beneath the hypopharynx, and is beneath of a horny texture; it forms a knee or articulating bend at about half its length, and has a second flexure at its apex, where the true tongue is inserted. This _labium_ is extensible and retractile at the will of the insect, and lies inserted within the under cavity of the head when in complete repose, and the insect can withdraw or extend a portion or the whole at its pleasure. Attached on each side, at its first bend or elbow, lie the _maxillæ_, which, for want of a better term, are called the lower jaws, and perhaps properly so from the function they perform; for at the point of their downward flexure, which occurs at the apex of the labium, and where the true tongue commences, they each extend forward in a broad, longitudinal membrane, partly coriaceous throughout its whole length, and these, folded together and beneath, form the under sheath of the whole of the rest of the lingual apparatus in repose, and often lap over its immediate base when even it