THE STRUCTURE OF THE BEE'S ST/.\<; 



175 



make attachment to two levers (/, i'). The levers (&, I and &', I 1 ) 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, so that, without relative movement of rod and groove, the points 



SC 



FIG. 195. Details of sting of bee : E, darts, sheath, and valves ; pb, poison-bag duct ; fo, fork ; 

 s, slide piece ; , valve ; b, barbs. F, terminal abdominal segments ; w, worker's sting ; q, queen's 

 sting ; /, r', anal plate ; G, sting entering skin ; sh, sheath ; a, b, o, positions in first, second, and 

 third thrusts with the sting. //, portion of poison gland, x 300 ; en, cell nucleus ; n, nerve ; g, 

 nnglionio cell. /, portion of the poison gland, cells removed: cd, central duct; d, individual small 

 ducts; pr, tunica propria. K, gland of Formica ri/fit : <</, central duct; </, small ducts; w, 

 secreting cells. Z, valve and support; f. trachea; va. valve; tr, truss or valve-prop. After 

 Cheshire. 



