96 The Honey-Makers 



where it widens into an oblong hollow pouch A, and it has 

 two rows of microscopic backward-pointing teeth at its tip, 

 although but one row can be seen at a time. The two 

 lances are very slender, very sharp, and lie side by side in 

 the groove on the under side of the sheath, fitting closely 

 in their place. These lances can be pulled out of the 

 groove as has been done at L, L. As they are hollow 

 within, they and the sheath together form a tube. They 

 are not stationary, however, but play up and down. 



In order to prevent the lances from slipping out of place 

 each is grooved along its outer edge, the grooves slid- 

 ing over a corresponding projection that runs along either 

 side of the sheath. Thus the lances ride up and down 

 in the sheath, held safely in place no matter how quickly 

 or violently they may move. 



Each lance is viciously barbed at its point with ten stout 

 hook-like projections that point backwards like the barbs 

 on a fish-hook. 



The poison-sac opens into the pouch A and on each 



lance where it lies in this pouch is a curiously constructed 



valve (X) which acts like the piston in a pump and 



pushes the poison through the tube in the sting as 



the lances are thrust down. 



The poison is supplied by a long, slender white 

 gland which at length branches into two and lies 

 coiled up like a white thread in the abdomen, ending 

 near the stomach in flattened knobs and opening be- 

 low into the poison-sac. 



When the bee stings, the end of the sheath is first 

 driven into the skin and held fast by the barbs at 

 the end. It now acts as a guiding rail as one after 

 the other the lances are forced down, at each thrust going 

 deeper into the victim. The poison escapes from the in- 

 terior tube through openings on the lower barbs of the 

 lances, 



