The Head, in common with that of other creatures, is the inlet for nutrition and the principal seat of the organs of sensation.—Of nutrition and sensation I shall speak in their appropriate places.
The Trunk is the intermediate section of the body between the head and the abdomen: it approaches in figure to a sphere, and is the seat of the organs of motion; it contains the muscles of the wings and legs which proceed from it, and is the main prop, or as it were the key-stone, of the other two sections. The upper side is called thorax or the chest, the under side pectus or the breast.
The Abdomen is the third section of the body, posterior to the trunk; it is divided into six rings or segments, which, by sliding one over another, serve to shorten or lengthen the body. It is the seat of the organs of generation, and principally of those connected with respiration; and contains also the anus and the sting. The upper part is called tergum or the back, the under side venter or the belly.
The Head.
The most remarkable part of the head is the Proboscis, of which so good an account has been given by Dr. Evans that I shall describe it nearly in his words.
It is not so much the mere simplicity of nature, which excites our wonder and admiration, as that apparently complex structure, which operates with all the ease of the simplest machinery. Of this we have not a more striking instance than in the proboscis of the labouring bee: though the component parts of the proboscis are scarcely discernible by the naked eye, yet are they far more complicated than the elephant’s stupendous trunk. It consists of no less than five distinct branches; namely, a central trunk, or tongue, and four horny scales, tapering to a point, convex outwards and concave towards the trunk; the two outer ones so sheath the inner as to appear but one single tube: by a joint in the middle they bend, or extend all at once, carrying with them the unarticulated tongue, which is cylindrical, and about the size of a man’s hair, and appears through a magnifier to be composed of successive rings. It has probably as many short muscles as the tongue of a fish, which are capable of moving it in all directions; and towards its termination is furnished with hairs or villi, some of which at the point are very long, and seem to act like capillary tubes. Mr. Wildman assures us, that he has seen the trunk growing bigger and less by turns, swelling the instant the bee sucked; and this alternate lessening and enlargement propagated from the extremity to the root. What a delicate apparatus of invisible muscles must perform this office! The tongue is capable of being contracted and folded up at pleasure; for if it were constantly extended, it would be exposed to injury: when at rest, therefore, it is doubled up by means of its joint, and lies in a very small compass; the first portion being brought within the lip, and the second part folded under the head and neck, protection is given to it by a double sheath, consisting of four strong scales, the two inner scales sheathing the tongue, and the two outer and larger ones encompassing the whole. When at work, the trunk is lengthened beyond its sheaths, probes the very bottom of the flowers, through all impediments of foliage or fructification, and drains them of those treasured sweets which, without such an apparatus, would be completely inaccessible.
The proboscis of the bee is not used like that of other flies, not being tubular like theirs, but serves as a brush or besom to sweep, or as a tongue to lap[K]; having collected the nectar of flowers in small drops, it deposits its collection upon the tongue, which is protruded for the purpose of receiving it, and having received it, withdrawn again.
[K] The bee and all other insects that lap their food are called lambent insects.
The Lips. The bee has two lips, an upper one called labrum, and an under one called labium; (the Mentum of Latreille.)
The Tongue of the bee, which is very long, is at its upper part cartilaginous; below the middle, membranous and capable of considerable inflation, thus forming a bag to receive the honey from the proboscis, preparatory to its conveyance into the pharynx. It terminates in a knob, but has no passage through it, to exercise the power of suction, as has been supposed. When in a state of inaction, it is folded up longitudinally, and lies between the lips. The tongue of the working bee is probably the largest of any known animal, for its size; it is much longer than that of either the male or queen, and thus fitted for taking up honey at a considerable depth. The bee has the power of unfolding it with great rapidity, and darting it betwixt the petals and stamina of those flowers that afford honey, it moves it about in every direction, sweeping the convex as well as the concave surface of the petals.