[Illustration: Fig. 9.—A, Proboscis of a "long-tongued" bee, _Anthophora pilipes_; B, lower, C, upper view of proboscis of an "obtuse-tongued" bee, _Prosopis pubescens_. _a_, Labrum; _b_, stipes; _c_, palpiger; _d_, scale: _f_, lobe; _g_, palpus; _h_, cardo, of maxilla: _i_, lorum; _k_, submentum; _l_, mentum; _m_, labial palp; _n_, paraglossa; _o_, ligula; _p_, tip of ligula (with "spoon" at tip and some of the hairs more magnified); _q_, hypopharyngeal sclerites.] The way in which the proboscis of the bee acts has been very largely discussed, with special reference to the question as to whether it is a sucking or a licking action. It is impossible to consider either of these terms as applicable. The foundation of the action is capillary attraction, by which, and by slight movements of increase and contraction of the capacity of various parts, the fluid travels to the cavity in front of the hypopharynx: here the scales of the maxillae leave a vacant space, (Fig. 7, _e_) so that a cup or cavity is formed, the fluid in which is within reach of the tip of the dependent epipharynx (_c_), which hangs down over the front of the hypopharynx (and is so shaped that its tip covers the cup); it is between these two parts that the fluid passes to reach the pharynx. It is no doubt to slight movements of the membranous parts of the hypopharynx and of the epipharynx that the further progress of the nectar is due, aided by contraction and expansion of the pharynx, induced by muscles attached to it. It should be recollected that in addition to the movements of the head itself, the hypopharynx is constantly changing its dimensions slightly by the impulses of the fluid of the general body cavity; also that the head changes its position, {18}and that the proboscis is directed downwards as well as forwards. Those who wish to pursue this subject should refer to the works of Breithaupt[15] and Cheshire. The other external characters of the Bees call for little remark. The pronotum is never very large or much prolonged in front, and its hind angles never repose on the tegulae as they do in the wasps,[16] but extend backwards below the tegulae. The hind body is never narrowed at the base into an elongate pedicel, as it so frequently is in the Wasps and in the Fossors; and the propodeum (the posterior part of the thorax) is more perpendicular and rarely so largely developed as it is in the Fossors; this last character will as a rule permit a bee to be recognised at a glance from the fossorial Hymenoptera.