638 THE POPULAR SCIENCE MONTHLY. 



run in the manner shown in Fig, 3. In this figure the darker portion 

 (w) represents a cross-section of the " sheath," the two lighter pieces 

 {b and d) are cross-sections of the lancets, one {d) in situ. Running 

 the entire length of the " sheath " we find the T-rail projections [g g) 

 along which the lancets slide, being channeled to fit, as seen at 5, Fig. 

 3. Thus we see that the main " sheath " is not a proper term for this 

 part of the apparatus, for the lancets are entirely outside of it and run 

 along the rails. The poison-gland (P) empties into the cylindrical part 

 of the sheath, and keeps it constantly full of virus, at least when the 

 bee is excited. A, B^ and C, are broad chitinous pieces, to which mus- 

 cles are attached. They form a peculiar combination of levers, too com- 

 plicated in their action to be described here in detail, but they serve to 

 thrust out tlie " sheath " and the lancets, giving to the former a power- 

 ful thrust, and to the latter a movement of great rapidity. 



We are now prepared to understand the operation of stinging. The 

 two lancets [K K) when in position lie close against the "sheath," as 

 already described, and their ends reach just to the point of the latter. 

 When the insect stings, the palpi {E E), which are drawn away from 

 their proper place in the figure, serve to direct the organ to the most 

 vulnerable point of attack. Then, with a sudden, powerful motion, the 

 " sheath " is forced out and produces the puncture, penetrating as far 

 as the point d, where the expansion begins. Instantly the two lancets 

 are then forced out together, increasing the depth of the wound made 

 by the " sheath." It has generally been supposed that the lancets were 

 the organs that made the puncture, but this is not the fact. The lan- 

 cets are thrust out until the stop-valves {p2^) strike against the shoulder 

 d (Fig. 1). This closes the cylindrical part of the sheath, which is full 

 of virus, and this virus, being under pressure either from the sudden 

 stoppage of the free outlet by the stojD-valves or the contractions of the 

 poison-gland (P), or both these causes combined, makes its way into 

 the tubular lancets through the openings already mentioned just back 

 of the stop-valves, and enters the wound through the branch-tubes 

 bhhbh (Fig. 2). Thus we see that the injection of the poison into the 

 wound is fairly comparable to the working of an hydraulic ram. 



When the honey-bee stings, it is well known that the sting is not 

 withdrawn from the wound. The sharp barbs on the lancets make it 

 impossible for the bee to withdraw them, but more than these may be 

 left behind. By allowing the insect to sting a piece of soft leather, not 

 only the lancets but also the sheath and poison-gland will be beautifully 

 dissected out, the bee apparently not suffering from their loss. 



It will be seen that the lancets are curved at their attachment with 

 the levers which move them. This curved portion is flexible, while the 

 points are brittle. The poison-gland is provided with a muscular coat. 

 It has been previously supposed that the virus was expelled from the 

 gland by the pressure of other parts. There are several interesting 

 points connected with the mechanism of the sting, which have been 



