Another provision of the bee's limbs consists in a pair of hooks attached to each foot, with their points opposite to each other, by means of which the bees suspend themselves from the roof or sides of hives, and cling to each other as they do at swarming time or prior to and during the formation of new comb, thus forming a living curtain. In these circumstances, each bee, with its two fore claws, takes hold of the two hinder legs of the one next above it.
This mode of suspension is, no doubt, agreeable to them, although the uppermost bees appear to be dragged by the weight of the whole. Wildman supposed that bees had a power of distending themselves with air, to acquire buoyancy, and thus lessen the burden of the topmost bees. They find no difficulty in extricating themselves from the mass; the most central of the group can make its way without endangering the stability of the grape-like cluster.
Bees are able to walk freely in an inverted position, either on glass or other slippery substances. The peculiar mechanism of their feet, which enables them to do so, consists in their having in the middle of each hook a thin membranous little cup or sucker that is alternately exhausted and filled with air. Flies have the same beautiful apparatus—hence a fly commonly selects the ceiling for a resting-place. These little air-cups, or exhausted receivers, may be seen by applying a strong magnifying-glass to a window that has a bee traversing the reverse side. The edges of these little suckers are serrated, so as to close against any kind of surface to which their legs may be applied. This apparatus may be also serviceable for gathering the pollen before transmitting it to the baskets on the hind legs. Besides these appendages and apparatus of the thorax, that region is traversed by the œsophagus or gullet (the opening to which will be found in [Plate I, fig. 2 c]), on its way to the digestive and other organs, situate in the third part of the insect—viz., the abdomen. The covering of the thorax, with the external covering of the gullet, may be seen in the drawing of the magnified dissected body of the bee ([Plate II., fig. 1]).
The breathing apparatus of bees is a very remarkable feature: they have no lungs, but, instead, air-vessels or tubes, ramifying through every part of the frame. These openings, called "spiracles," are found in the sides of their bodies, behind the wings. Two of the openings are located in the thorax, and one on each side of the scales of the abdomen.
These air-vessels would be difficult to show in a drawing, the multitude of hairs which protect them are in the way of getting at a very distinct delineation. The writer has traced their oval form by the aid of Messrs. Smith and Beck's "Binocular Microscope," and exceedingly interesting objects they appeared. From the circumstance of bees breathing through these orifices in their bodies, it will not be difficult to understand how sadly the little creatures must be inconvenienced when, by accident, they fall on loose mould, and thus have their breathing pores choked with dust: it also shows how needful it is to prevent bees being besmeared with honey (by using bad appliances for feeding), which is still more injurious to them. These air-vessels are the only real circulating system, as bees have neither lungs, heart, liver, nor blood. It appears, however, that a white fluid matter, called "chyle," which, in degree, answers the purpose of blood, is produced in the intestines, nourishes the body, receives the oxygen from the air-vessels, and generates that animal warmth so necessary for the insect's well-being. Bees have the power of counteracting superabundant heat by perspiration. Not unfrequently, on a hot summer's morning, a good deal of moisture may be noticed at the entrance of a crowded hive, which the inmates have been enabled to throw off. This is a healthy sign, because a sign of great numerical strength.
The abdomen, attached to the posterior part of the thorax by a slender ligament, has, for an outer covering, six folds or scales of unequal breadth, overlapping each other, and contains the honey-bag, or first stomach, the ventricle, or true stomach ([Plate II., figs. 1 and 2f]), with other intestines, to be hereafter referred to.
The honey-bag ([Plate II., figs. 1 and 2, d]) is an enlargement of the gullet, and, although called the first stomach, no digestion takes place here. In shape it is like a taper oil flask; when full, it is about the size of a small pea, and so transparent that the colour of the honey may be seen through it. This sac, as it is sometimes called, is susceptible of contraction, and so organized as to enable the bee to disgorge a part of its contents at pleasure, to fill the honey-cells of the hive. It has formed a subject of some controversy whether any or what change takes place in the nectar of flowers whilst in the bee's stomach.
A short passage ([Plate II., figs. 1 and 2, f]) leads to the ventricle or true stomach, which is somewhat larger. This receives the food from the honey-bag, for the nourishment of the bee and the secretion of wax. The stomach, like the honey-bag, has a considerable number of muscles, which are brought into play to help the digestive and other organs. The biliary vessels ([Plate II., figs. 1 and 2, h, h]) receive the chyle from the digested food in the stomach, which from thence is conveyed to all parts of the body for its support.
Formerly, naturalists thought that wax was elaborated from pollen; but it is now fully known that it is the animal fat of the bees, and to produce it requires a considerable consumption of honey to supply the drain upon the system. Whilst this secretion is going on, bees keep themselves very still. In order to pass through the pores of the abdomen, the wax is, no doubt, a liquid oily matter, which, on making its appearance outside the abdominal rings, thickens, and exudes from under the four medial rings, in flakes like fish scales, one on either side; so that there are eight of these secreting cavities, which are peculiar to the worker: they are not found either in the queen or drone. The shape of these cavities is that of an irregular pentagon, and the plates of wax, being moulded in them, exhibit accordingly the same form (see [Plate II., fig. 5, w]).
No direct channel of communication between the stomach and these receptacles, or wax-pockets, has yet been discovered; but Huber conjectures that the secreting vessels are contained in the membrane which lines these receptacles, and which is covered with a reticulation of hexagonal meshes, analogous to the inner coat of the second stomach of ruminant quadrupeds.