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The first of these five limbs, the coxa or hip, is short and round, being the joint that articulates with the body (Pl. VI. fig. 1, a); the second, the trochanter (b), another small roundish joint; then the femur (c), a thin elongated division; the tibia (d), a stout thick limb, which in the hind-leg becomes gradually wider as it recedes from the preceding one ; and lastly, the tarsus or foot (e), which is subdivided into five smaller articulations or segments, the terminal one comprising a pair of hooked claws.
A comparison of the figures representing the three kinds of Bee (worker, drone, and queen) will serve to show you that the legs vary somewhat in their proportions; but as the posterior or hinder pair, especially in the worker-bee, possess all the interesting features common to the remaining pairs, and some characteristics peculiar to themselves, we shall only bring our lens and microscope to bear upon the remarkably constituted hind-legs.
The most superficial inspection of one of these members (Pl. VI. fig. 1) cannot fail to suggest the idea that it must perform some other function besides that of locomotion. First of all, its limbs or joints are of a very curious shape, and unlike those of other insects; for the fourth limb or tibia (d) becomes very broad as it approaches the fifth, that is, the tarsus, the first joint of which is also very largely developed (e), being of an oblong shape, and covered over its whole surface with regular rows of long stiff hairs. And then, if you examine the junction of
these two divisions of the leg (Pl. VI. fig. 1,j, and fig. 2), another peculiarity presents itself: namely, a cavity formed by the uppermost edge of the first joint of the tarsus and the lower edge of the tibia, which cavity (Pl. VI. fig. 2) resembles an open vice, and may be closed from the joint at the will of the insect. But this is not all: on the upper side of this receptacle (for this is the well-known pocket or pollenbasket of the Bee), you will find a row of long lancetor sword-shaped hairs (Pl. VI. fig. 2, a'), regarding the use of which we need not long remain in doubt. Here it is that the industrious worker commences the storing up of her "bee-bread," which consists of the pollen of flowers moistened with honey; the first deposition being no doubt pressed together and consolidated by the prongs and the vice referred to, and particle after particle added, and in like manner rendered consistent by the rows of long hairs distributed over the first joint of the tarsus, until the whole pollenmass assumes the form of those curious pellets that you may see encumbering the little caterer as she returns home from her aërial wanderings. The sides of the tibia, as well as those of the first joint of the tarsus, are slightly hollowed, whereby the deposition and retention of the bee-bread are greatly facilitated.
And now let us travel on to the last joint of the tarsus (Pl. VI. fig. 1, e', & fig. 3), furnished with its remarkable terminal claws, and we shall find that it is hardly surpassed in interest by the wonderful feet
of the Housefly, whereby that insect is enabled to progress so readily upon glazed or inverted surfaces*.
In the Bee the claws are forked (Pl. VI. fig. 3), and not simple, as in the Fly; and whilst the latter has two beautiful pads, the insect under consideration is provided with only one central, hollow, cupshaped organ (Pl. VI. fig. 3, a), studded all over with innumerable hairlets. The reason for this difference in the construction of the feet of the two insects is obvious enough. The central cup-shaped organ of the Bee no doubt operates as do the pads in the Fly, giving the insect a hold upon smooth surfaces: but, as you will probably yourself have noticed, the Bee does not move over such surfaces with the same facility as the Fly, nor has it occasion so to do; it has therefore only one pad, more simple than those of the Fly. But, on the other hand, having frequent occasion to use its claws in its domestic operations, such as the adjustment of wax, pollen, &c., these instruments are, as just observed, of a more complicated structure than those of the Housefly.
Thus you see that even on the hind-leg of a Bee, there are to be found various appliances well adapted to the uses for which they are intended, but not at all requisite for the mere act of locomotion; and if we now proceed to investigate the wings of the insect, we shall in like manner be surprised at the discovery of exquisite contrivances that are applicable * Earthworm and Housefly,' p. 51.
to other uses than that for which organs of flight are usually destined. The wings are, as before stated, four in number, the anterior pair being the largest (Pl. II. figs. 1, 4). They are composed of a double membrane which is covered all over with fine hairs, and stretched out upon what are termed "nervures," or ribs, that ramify between the double fold. (Pl. VI. fig. 4.)
Accompanying the nervures are also to be found a set of vessels for the circulation of air (trachea), and another set for the passage of blood; and although the nervures are not so numerous in this as in some other insects, they are of a firm consistent nature, giving to the wings that tough membranous texture which characterizes the order (Hymenoptera).
But you may be disposed to ask why the wings of a Bee should require to be tougher and more resisting than those of other insects. This would be a very natural inquiry, and one that we shall seek to answer satisfactorily; but, before doing so, let us for a moment direct your attention to another feature in connexion with these organs. Supposing it to be necessary that they should offer great resistance to the atmosphere and present the broadest possible unbroken surface, this object would of course be greatly facilitated if the two pairs of wings could be locked together in such a manner that it would be impossible for a current of air to pass between them. Well, then, without rendering them permanently adherent, which would make it inconvenient for the insect to
fold its wings, Nature has, by a beautiful but simple contrivance, attained this end: for, if you take your lens and examine the anterior or front edge of the hinder wing (Pl. VI. fig. 4, h and Pl. V. fig. 5), you will be surprised to find a row of exquisitely formed hooks; whilst, on the opposite edge of the anterior wing with which this row of hooks comes into immediate contact, you will be able to detect a species of rib or bar (Pl. V. fig. 6, 6), to which the hooks may be made to adhere firmly, and both wings thus attached to one another when requisite, presenting the desired unbroken surface to the atmosphere.
And now, reader, the reason why these wings are of a tough resisting nature, and so wonderfully organized, is because they are not only employed in flight, but also (as we shall see hereafter) in the ventilation of the hive: in the latter capacity the insects cause them to vibrate very rapidly, so as to create a current; in fact, they operate precisely on the principle of the fan. It is hardly necessary, we presume, to point out to you how inefficient such an instrument would be if it had a slit down the middle; and you will now perceive why it is necessary that the fore and hind wings of the Bee should be capable of being locked together, so as to present one continuous unbroken surface.
At the roots of the wings, upon what is termed the sub-costal nerve, there are to be found a number of pear-shaped vesicles, of a somewhat similar character to those described upon the antennæ; here, however,