NO. 2 HONEY BEE SNODGRASS 85 



In the male bee the dorsum of the exposed part of the abdomen 

 ends with the declivous tergal plate of segment VIII (fig. 29 A), 

 but the sternum of this segment (VI IIS) is concealed within that of 

 segment VII, and the visible part of the venter terminates with 

 sternum IX. The tergum of segment IX, however, is represented 

 only by a pair of small dorsal sclerites lying at the sides of the 

 proctiger (figs. 29 A, 30 A, IXT), each of which supports internally 

 a large apodeme (fig. 29 A, ap) giving attachment to the dorsal 

 muscles of its segment (B). The sternum of segment IX (figs. 29 A, 

 30 A, B, IXS) is a relatively large crescentic plate exposed beyond 

 sternum VII, and bears on its posterior margin the two pairs of phallic 

 plates {Ip, pv). The proctiger is a membranous lobe (fig. 30 A, Ptgr) 

 with a small subanal plate (b) in its ventral wall between the two 

 sclerites of the ninth tergum. 



In the queen and the worker bee the exposed part of the abdomen 

 ends with the tergum and the sternum of segment VII (fig. 27 A). 

 The margins of the apical plates are ordinarily closed upon each 

 other, concealing a large invagination cavity that contains segments 

 [//// and IX, the proctiger, and the sting. Segment VIII is a 

 complete annulus at the base of the cavity, but its walls are mem- 

 branous except for two lateral remnants of the tergum, which contain 

 the spiracles and are associated with the base of the sting. The 

 tergites of segment VIII, therefore, are known as the spiracular 

 plates of the sting (fig. 28 C, VIIIT). In the posterior wall of the 

 ventral part of the eighth segment is a depression containing the 

 female genital openings (D). Segment IX supports the sting, but 

 it is hardly to be recognized as a segment; its only sclerotized parts 

 are two lateral tergal plates that form virtually a part of the stinging 

 apparatus (fig. 31 A, Qd), and are hence called, because of their 

 position and shape, the quadrate plates of the sting. The venter of 

 the ninth segment {IX. V) is entirely membranous and, when the 

 sting is retracted, is mostly concealed between the oblong plates {Ob) 

 of the basal apparatus of the sting. 



The abdominal musculature. — The musculature of the abdomen 

 follows a definite plan, the pattern of which is repeated alike in each 

 of the segments, except for omissions in the first and the last three 

 segments, and the addition of a few special muscles in connection 

 with the genital organs and the sting. The typical segmental mus- 

 culature is complete in segments /// to VI in both sexes, but the 

 individual muscles of the male (fig. 29 B) are much larger than those 

 of the female (fig. 28 A). The somatic abdominal muscles, exclusive 



