§ IV. THE ABDOMEN AND SECRETIVE ORGANS.
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 2 f]), with other intestines, to be hereafter referred to.
The honey-bag ([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 organised as to enable the bee to disgorge a part of its contents at will, to fill the honey-cells of the hive. It has been much controverted whether any or what change takes place in the nectar of flowers whilst in the bee's stomach ([Chap. VI. § iii.]).
A short passage leads to the ventricle or true stomach ([Figs. 1 and 2 f]), 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 ([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. "A bee," says Dzierzon, "with the honey which she can take into her stomach, is able to subsist abundantly under some circumstances for longer than a week, while under others she will die of hunger within twenty-four hours. If we regard life as a process of combustion, then with the bee it resembles at one time the spark just glimmering in the ashes, at another the bright up-bursting flame that in a few minutes consumes the fuel, which to the barely glimmering fire would have ensured nutrition for a much longer time."
Wax is the animal fat of the bees, and to produce it requires a considerable consumption of honey to supply the drain upon the system. To be capable of passing through the pores of the abdomen, the wax must no doubt be a liquid oily matter, which, on making its appearance outside the abdominal rings, thickens, and exudes from under the four medial ones, in flakes like fish-scales, one on each side; so that there are eight of these secreting cavities, which are peculiar to the worker, not being 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. 6 w]). No direct channel of communication between the stomach and these receptacles, or wax-pockets, has as yet been discovered; but Huber conjectures that the secreting vessels are contained in the membrane which lines them, and which is covered with a reticulation of hexagonal meshes, analogous to the inner coat of the second stomach of ruminant quadrupeds.
The last important organ of the abdomen is the sting. This small but effective weapon is situate close to the stomach, and is found in the queen and worker, but is absent in the drone. Our engraving ([Plate II. Fig. 4]) exhibits the sting of the worker bee with its muscles and attachments: r shows the muscles that move the sting, and q the curved base of the outer sheath by which it is enclosed. Much beautiful mechanism is observed on a microscopic examination of this weapon, so wonderfully powerful in comparison with its bulk. The sting is composed of three separate portions, each of which is double—the dart, and the inner and outer sheaths. Very confusing accounts are given of this organ in different works, owing probably to the term "sheath" being applied by some to the outer and by others to the inner covering. The outer one consists of two fleshy curved claspers (q in the figure), inside of which is the linear sheath, which forms an essential portion of the sting, and consists of two horny scales closely adherent to the darts. These last are composed of stiff filaments, which at the outer end are each barbed with from five to ten teeth on one side; and they slide within the inner sheath, and that within the outer, on the principle of the tubes of a telescope. As represented in our engraving, the inner sheath clasps the darts to a level with the tips of the outer one.
The darts are first protruded in the act of stinging, and, by aid of the powerful muscles on each side at s, are buried in the flesh to the depth of one-twelfth of an inch; the inner sheath then follows, and at the same time, by a muscular contraction, the poison is forced along the groove in which the darts work, causing the well-known painful effects which arise from the sting of a bee. These darts are of slightly unequal length, so that the teeth on each side are not opposite to each other. From this arrangement it is easier for them to penetrate the flesh, and alternately deepen the wound, while the teeth successively hold each firm as it makes its way, until the poison has been ejected. If the sufferer could only command himself so as to remain perfectly passive, the bee might be able to draw in these darts which protrude beyond the sheath, and would then have a chance of withdrawing the sting; the little insect would consequently inflict less pain, and might perhaps escape paying the penalty of her life. It generally happens, however, that the excitement of both parties is so great, that the poor bee leaves behind the whole apparatus, and even part of her intestines, so that her death is the result, and the wound is more severe. The sting is about the sixth part of an inch long, and is largest at the base. Here are situated the glands or ducts ([Fig. 4 u]). By these the poison is secreted and passed into the poison-bag ([Fig. 4 t]), which acts as a reservoir for retaining it till required.
On the subject of the sting Paley remarks: "The action of the sting affords a beautiful example of the union of chemistry and mechanism: of chemistry, in respect to the venom, which in so small a quantity can produce such powerful effects; of mechanism, as the sting is not a simple but a compound instrument. The machinery would have been comparatively useless had it not been for the chemical process, by which, in the insect's body, honey is converted into poison; and, on the other hand, the poison would have been ineffectual without an instrument to wound and a syringe to inject the fluid." As before stated the drone has no sting, but, in place thereof, the organs of reproduction, on which, as on the corresponding organs of the queen, sufficient has been remarked above (pages [24] and [63]).
And now, in concluding this section, we would remark the wonderful contrivance and finish which all the works of the Great Master Artificer unfold. In the works of man we see, perhaps, a piece of mechanism of unquestioned beauty and excellence, yet there is a bolt here or a screw there that might have been dispensed with, and does not possess any definite use. But in the works of Nature everything has a place; we may not at once comprehend the exact purpose of some intricate parts, but that only implies that we have not made a thorough investigation. The most minute hair serves its required end. Some reflections of Dr. Evans, though chiefly referring to the cells of bees, may not inappropriately finish this chapter:—
"On books deep poring, ye pale sons of toil,