THE ABDOMEN, WAX GLAND.S, AND STING. 



81 



PsnC-, 



PsnC' 



or! the other hand, the hmcets are retracted the pouches collapse so 

 that they may be drawn back through the poison-filled bulb without 

 resistance, l)iit they are ready for action again as soon as the move- 

 ment of the lancets is reversed. The whole apparatus thus consti- 

 tutes an actual force pump in which the lobes on the lancets alter- 

 nately act as a piston and as valves. The lancets need not work 

 together ; in fact, 

 they more often > -^^^ 



perhaps work al- 

 ternately, the lobes 

 being of such a 

 size as to be ef- 

 fective either when 

 acting together or 

 separately. 



The reader ac- 

 quainted with 

 other Avorks on 

 the anatomy of 

 the bee, such as 

 those of Cheshire 

 (18 8 6), Cook 

 (1004), Cowan 

 (1004), and Arn- 

 hart (lOOG), will 

 see often repeated 

 the statement that 

 the poison leaves 

 the sting both by 

 a ventral opening 

 between the lan- 

 cets near their tips 

 and by several lat- 

 eral pores near the 

 ends of the lancets 

 opening from the 

 poison canal upon 

 the bases of the barbs. The writer, hoAvever, has never been able 

 to observe the exit of the poison from any such lateral pores, while, 

 on the other hand, it is very easy to watch it exude from between 

 the lancets on the ventral side of the sting near the tip. If an 

 excited bee is held beneath a microscope and the tip of the sting 

 observed, the poison will be seen to accumulate in little drops near 

 the tip on the ventral side. If, also, the bulb of an extracted sting 

 22181— No. IS— 10 G 



Fit;. 40. — Di'lails of slinj; of worker: A, section through tip of 

 stiug sliowiug lancets (Let) and sl-afl of sheath (tfhS) sur- 

 rounding central poison canal (fs/if), and each containing 

 a iirolongation of the body-cavity (tic) ; B, section of same 

 near base of bulb ; C, section of sting througb basal bulb, 

 showing poison canal as large invaginatod cavity (PsnC) 

 in bulb of sheath {8hB) containing the two valves {Vlv) 

 of lancets {Let) ; D, part of loft lancet carrying valve {Vlv), 

 dorsal view ; E, tip of lancet showing pores opening on 

 bases of barbs {oo) coming from body-cavity {be) of lancet — 

 not from poison canal ; F, dorsal view of shaft of sheath 

 showing lateral series of pores {oo) from prolongation of 

 body-cavity {be) ; G, lateral view of left valve and part of 

 lancet. 



