THE ABDOMEN, 



75 



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

 posterior ends of the plates two whitish fingerlike processes (StnPlp) 

 project backward. When the sting is retracted these lie at the sides 

 of the shaft (figs. 33 and 37), but in figure 36 the sting is shown in a 

 partly protracted position. These appendages, often called the sting 

 palpi, undoubtedly contain gAse organs of some sort by means of 

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

 upon which she desir^ to use her sting. 



A 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 ^mple, solid, tapering, spearlike rod, but is a hollow 

 organ made of ithree pieces which surround a central canal. One of 

 these pieces is dorsal (fig. 36, ShS) and is the true prolongation of 

 the bulb (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 

 (ShA); which is like- 

 wise a prolongation 

 of the bulb, and a 

 ventral or anterior 

 piece (Let) , which is 

 continuous with the 

 ventral rod of the 

 shaft on the same 

 side. Hence the sting 

 may be analyzed into 

 three elements, which 

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

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

 large cavity, of a terminal tapering sho.ft{ShS) , and of two curved 

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

 rods, called the lancets 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). The 

 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 of 

 the sting 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. 



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

 from the bulb by an oblong plate (fig. 36, Ob), which normally over- 



FiG. 36. — Semidiagrammatic view of left side of sting of 

 worlier, accessory plates {Trij Oh, Qd), sting palpus 

 iStnPlp), alkaline poison gland (BOl), and base of large 

 poison sac (Psn^c) of acid gland. 



