Now, if you take another glance at the basket-joint in the forceps of the microscope, you will see—what, perhaps, you have already noticed—that the marginal spines have not exactly the same curvature on the two opposite edges, but that those of the one edge are nearly straight, or at most but slightly bowed, whereas those of the opposite edge are strongly curved, the arc in many of them reaching even to a semicircle ; so that their points, after performing the outward arch, return to a position perpendicularly over the medial line of the basket.

It is the outer or hinder edge of the joint that carries the comparatively straight spines. These receive the grains from the combs, which, then falling into the basket, are received into the wide concavity formed partly by its bottom and sides, but principally by the arching sjnnes of the opposite edge. Their curving form would have been less suitable than the straighter one to pass through the interstices of the combs, because it would be much more difficult to get at their points; while, on the other hand, the straight lines of these would have been far less effective as a receiver of the burden. The thickness of the spines is just that which enables them to pass freely through the interstices of the comb-teeth, and no more.

On the whole, this combination of contrivances reads us as instructive a lesson on the wisdom of God displayed in creation as any that we have had brought under our observation.

The end to be attained by all this apparatus is worthy of the wondrous skill displayed in its contrivance; for it is connected with the feeding of the stock ; and whatever diminishes the labour of the individual bees, enables a larger number to be supported. But, valuable as is the Honey-bee to man, there are other important purposes to be accomplished, which are more or less dependent, collaterally, on this series of contrivances.

" In many instances it is only by the bees travelling from flower to flower that the pollen and farina is carried from the male to the female flowers, without which they could not fructify. One species of bee would not be sufficient to fructify all the various sorts of flowers, were the bees of that species ever so numerous ; for it requires species of different sizes and different constructions. M . Sprengel found that not only are insects indispensable in fructifying different species of Iris, but some of them, as /. Xiphium, require the agency of the larger humblebees, which alone are strong enough to force their way beneath the style-flag ; and hence, as these insects are not so common as many others, this Iris is often barren, or bears imperfect seeds." *

The legs and feet of Caterpillars are constructed on a very different plan from those of perfect insects, as you may see in this living Silkworm. The first three segments of the body, reckoning from the head, are furnished each with a pair of short curved limbs set close together on the under side. These represent the true legs of the future moth, and show, notwithstanding their shortness, four distinct joints, of which the last is a little pointed horny claw. The whole limb resembles a short stout hook. Then two segments occur which are quite smooth beneath, and destitute of limbs; and then on the sixth we begin to find another series, which goes on regularly, a pair on each segment, to the eleventh and final one, with the single exception of the tenth segment, which is again deprived of limbs.

But these organs are of a very peculiar character. They have no representatives in the mature insect, but disappear with the larva state; and they are not considered limbs-proper at all, but merely accessory developments of the skin to serve a special purpose. They are sometimes called claspers, sometimes false-legs, but more commonly pro-legs.

Each consists of a fleshy wart, which is capable to some extent of being turned inside out, like the finger of a glove. Partly around the blunt and truncate extremity are set two rows of minute hooks, occupying the side next the middle line of the caterpillar in a semicircle alon^ the mannn. These hooks arch outward

Penny Cyclop., art. Bee. The researches of the late Mr. Darwin and others have shown that the agency of insects in the fertilization of plants is very far more important than had been suspected.

as regards the axis of the pro-leg, though the majority of them point towards the medial line of the body. The double row is somewhat interrupted at its middle point ; and just there, in each pro-leg, a clear vesicle or fleshy bladder protrudes from the sole, which may perhaps serve as a very delicate organ of touch, or may exude a viscid secretion helpful to progress on smooth bodies. The hooks seem adapted to catch and hold the fine threads of silk, which most caterpillars spin as a carpet for their steps.

In some cases the circle of hooks is complete, as in this example, which I find in one of the slides of my drawer, marked "Pro-leg of a Caterpillar." It is some large species, probably a Sphinx, for the hooks are very large, of a clear orange-brown hue, and set in a long oval ring—single as to their basis, but double as to their points—completely around the extremity of the foot. These hooks belong only to the skin, as may be well seen in this prepared specimen, doubtless mounted in Canada balsam;—for their roots are mere blunt points, set but little below the surface of the thin skin, without any enlargement or apparent bulb.

Chapter VIII. Insects: their Stings and Ovipositors

insects: stings and ovipositors.

CHAPTER VIII.

INSECTS : STINGS and ovipositors. Probably at some period of your life you have been stung by a bee or wasp. I shall take it for granted that you have, and that, having tasted the potency of these warlike insects' weapons with one sense, you have a curiosity to examine them with another. The microscope shall aid your vision to investigate the morbific implement.

This is the sting of the Honey-bee, which I have but this moment extracted. It consists of a dark brown horny sheath, bulbous at the base, but suddenly diminishing, and then tapering to a fine point. This sheath is split entirely along the inferior edge, and by pressure with a needle I have been enabled to project the two lancets, which commonly lie within the sheath. These are two slender filaments of the like brown horny substance, of which the centre is tubular, and carries a fluid, in which bubbles are visible. The extremity of each displays a beautiful mechanism, for it is thinned away into two thin blade-edges, of which one remains keen and knife-like, while the opposite edge is cut into several saw-teeth pointing backwards.

The lancets do not appear to be united with the sheath in any part, but simply to lie in its groove ; their basal portions pass out into the body behind the sheath, where you see a number of muscle-bands crowded around them : these, acting in various directions, and being inserted into the lancets at various points, exercise a complete control over their movements, projecting orretracting them at their will. But each lancet has a singular projection from its back, which appears to act in some way as a guide to its motion, probably preventing it from slipping aside when darted forth, for the bulbous part of the sheath, in which these projections work, seems formed expressly to receive them.

Thus we see an apparatus beautifully contrived to enter the flesh of an enemy : the two lancets finely pointed, sharp-edged, and saw-toothed, adapted for piercing, cutting, and tearing ; the reversed direction of the teeth gives the weapon a hold in the flesh, and prevents it from being readily drawn out. Here is an elaborate store of power for darting them forth, in the numerous muscle-bands ; here is a provision made for the precision of the aim ; and, finally, here is a polished sheath for the reception of the weapons and their preservation when not in actual use. All this is perfect; but something still was wanting to render the weapons effective, and that something your experience has proved to be supplied.

The mere insertion of these points, incomparably finer and sharper than the finest needle that was ever polished in a Sheffield workshop, would produce no sensible result on our feelings ; and most surely would not be followed by the distressing agony attendant on the sting of a bee. We must look for something more than we have seen.

We need not be long in finding it. For here, at the base of the sheath, into which it enters by a narrow neck, lies a transparent pear-shaped bag, its surface covered all over, but especially towards the neck, with small glands set transversely. It is rounded behind, where it is entered by a very long and slender membranous tube, which, after many turns and windings, gradually thickening and becoming more evidently glandular, terminates in a blind end.

This is the apparatus for preparing and ejecting a powerful poison. The glandular end of the slender tube is the secreting organ : here the venom is prepared ; the remainder of the tube is a duct for conveying it to thebag, a reservoir in which it is stored for the moment of use. By means of the neck it is thrown into the groove at the moment the sting is projected; thesame muscles, probably, that dart forward the weapon compressing thepoison-bag, and causing it to pour forth its contents into the groove, whence it passes on between the two lancets into the wound which they have made.*

A modification of this apparatus is found throughout a very extensive order of Insects,—the Hymenoptera ; but in the majority of cases it is not connected with purposes of warfare. Wherever it occurs it is always confined to the female sex, or (as in the case of some social insects) to the neuters, which are undeveloped females. When it is not accompanied by a STING OF BEE. poison-reservoir it is used a. Tip of Lancet, more enlarged.

Some further researches of value on the stings of Wasps and Bees, with copious illustrations, will be found in Hardwicke's Science-Gossip for 1868, p. 148, by Dr. Mills, p. 205, by " S. &," and for 1873, p. 132, by Mr. Nisbett Browne.

for the deposition of the eggs, and is hence called an ovipositor, though in many cases it performs a part much more extensive than the mere placing of the ova.

In the large tribe of Cuckoo-flies (Ichneumonidce) which spend their egg- and larva-states in the living bodies of other insects, this ovipositor is often of great length; even many times longer than the rest of their bodies ; for the larvae which have to be pierced by it require to be reached at the bottom of deep holes, and other recesses, in whicli the providence of the parent had placed them for security. The structure of the organ may be seen in this little species, not more than one-sixth of an inch in entire length, of which the ovipositor projects about a line. Under the microscope you see that this projection consists of two black fleshy filaments, rounded without and flattened on their inner faces, which are placed together, and of the true implement for boring, in the form of a perfectly straight awl, of a clear amber hue, very slender, and brought to an abrupt oblique point, where there are a few exceedingly fine reverted teeth. It is probably double, though it refuses to open under the pressure which I bring to bear upon it. At the base are seen Avithin the semi-pellucid abdomen the slender horns, on which the muscles act in projecting the borer.

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