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Fig. 191.—A, end of larva of Encyrtus of 2d stage, showing the three pairs of imaginal buds of the ovipositor q1, q2, q3. B, the same in an older larva ready to transform; i, intestine; x, genital gland; a, anus.—After Bugnion.

An excellent account of the honey-bee’s sting is given by Cheshire (Figs. 194, 195). The outermost of the three pairs of stylets forming the apparatus is the two thick, hairy “palpi” or feelers (P), these being freer from the sting proper than in the ovipositor of Orthoptera. The sting itself is composed of the two inner pairs of stylets; one of these pairs is united to form the sheath (sh), while the other pair form the two barbed darts. The sheath has three uses: first, to open the wound; second, to act as an intermediate conduit for the poison; and third, to hold in accurate position the long barbed darts. The sheath does not enclose the darts as a scabbard, but is cleft down the side presented in Fig. 194, which is below when the sting points backward. But, says Cheshire, as the darts move up and down, they would immediately slip from their position, unless prevented by a mechanical device, exhibited by B and C, giving in cross-section sheath and darts near the end, and at the middle of the former. “The darts (d) are each grooved through their entire length, while upon the sheath (sh) are fixed two guide rails, each like a prolonged dovetail, which, fitted into the groove, permits of no other movement than that directly up and down.” The darts are terminated by ten barbs of ugly form (D, Fig. 194), and much larger than those of the sheath, and as soon as the latter has established a hold, first one dart and then the other is driven forward by successive blows. These in turn are followed by the sheath, when the darts again more deeply plunge, until the murderous little tool is buried to the hilt. But these movements are the result of a muscular apparatus yet to be examined, and which has been dissected away to bring the rigid pieces into view. The dovetail guides of the sheath are continued far above its bulbous portion, as we see by E, Fig. 195; and along with these the darts are also prolonged upward, still held to the guides by the grooved arrangement before explained; but both guides and darts, in the upper part of their length, curve from each other somewhat like the arms of a Y, to the points c, c′ (A, Fig. 194), where the darts make attachment to two levers (i, i′). The levers (k, l and k′, l′) are provided with broad muscles, which terminate by attachment to the lower segments of the abdomen. These, by contraction, revolve the levers aforesaid round the points f, f′, so that, without relative movement of rod and groove, the points c, c′ approach each other. The arms of the Y straighten and shorten, so that the sheath and darts are driven from their hiding-place together and the thrust is made by which the sheath produces its incision and fixture. The sides being symmetrical, we may, for simplicity’s sake, concentrate our attention on one, say the left in the figure. A muscular contraction of a broad strap joining k and d (the dart protractor) now revolves k on l, so that a is raised, by which clearly c is made to approach d; i.e. the dart is sent forward, so that the barbs extend beyond the sheath and deepen the puncture. The other dart, and then the sheath, follow, in a sequence already explained, and which G, Fig. 195, is intended to make intelligible, a representing the entrance of the sheath, b the advance of the barbs, and c the sheath in its second position. The barb retractor muscle is attached to the outer side of i, and by it a is depressed and the barbs lifted. These movements, following one another with remarkable rapidity, are entirely reflex, and may be continued long after the sting has been torn, as is usual, from the insect. By taking a piece of wash-leather, placing it over the end of the finger, and applying it to a bee held by the wings, we may get the fullest opportunity of observing the sting movements, which the microscope will show to be kept up by continued impulses from the fifth abdominal ganglion and its multitudinous nerves (n, Fig. 194, A), which penetrate every part of the sting mechanism, and may be traced even into the darts. These facts, together with the explanation at page 49, will show why an abdomen separated many hours may be able to sting severely, as I have more than once experienced.