THE ABDOMEN, WAX GLANDS. AND ^^TTNG. 



75 



(PsnSc and BGl) open into the anterior end of the bulb. From the 

 posterior ends of the pLates two whitish fingerlike processes {StnPlp) 

 Droiect backward. When the sting is retracted these he at the sides 

 of the shaft (figs. 33 and 37), but in fignre 3G the sting is shown in a 

 partly protracted position. These appendages, often called the sting 

 palpi nndonbtedly contain sense organs of some sort by means of 

 which the bee can tell when her abdomen is in contact with the object 

 uTDon which she desires to use her sting. 



V close examination of the sting shows that it is a much more com- 

 plicated structure than it at first sight appears to be. The shaft for 

 example, is not a simple, solid, tapering, spearlike rod, but is a hollow 

 orcan made of three pieces which surround a central canal. One ot 

 these pieces is dorsal (fig. 30, ^hS) and is the true prolongation of 

 the ]3ulb (ShB), while the other two {Let) are ventral and slide 

 lengthwise on tracklike ridges of the dorsal piece. Moreover, each 

 basal arm of the 

 sting is double, con- 

 sisting of a dorsal 

 or posterior piece 

 (^/i/1), which is like- 

 wise a prolongation 

 of the bulb, and a 

 ventral or anterior 

 piece {Lct)^^\\\ch is 

 continuous with the 

 ventral rod of the 

 shaft on the same 

 side. Hence the sting 

 may be analyzed into 



three elements, which 7 ^i 



are characterized as follows: The dorsal piece, known as ihe sheath, 

 consists of a prominent basal swelling or Ulh (ShB) containing a 

 large cavity, of a terminal tapering shaft {ShS), and of two curved 

 hasal arms (ShA). The ventral part consists of two long slender 

 rods called the laneets or darts {Let), which slide freely upon two 

 tracks on the ventral edges of the sheath and diverge upon continua- 

 tions of these tracks along the basal arms of the latter {ShA). ihe 

 bulb is hollow, containing a large cavity formed by invagination 

 from below, where it is open to the exterior by a lengthwise cleft^ 

 This cavity continues also through the entire length of the shaft ot 

 the stincr as a channel inclosed between the dorsal sheath and the 

 latero-ventral lancets. This channel, as will be explained later, is 

 the poison canal of the sting. i j. .i i. 



Each arm of the sheath {ShA) is supported at its end farthest 

 from the bulb by an ohlong plate (fig. 3G, Oh), which normally over- 



Pif, ;>fi— Somidiagrammatic viow of left side of sting of 

 worlvor accessory plates (Tri. Oh, QdU sting palpus 

 (l-iluPJp). alkaline poison gland {BOD, and base of large 

 poison sac (f'suSc) of acid gland. 



