132 THE ANATOMY OF THE HONEY BEE. 



1. THE MALE ORGANS. 



The reproductive organs of the drone are shown by figure 56 A, 

 They consist of the testes (Tes), the vasa deferentia (VDef), the 

 vesiculm semifiales (Ves), the accessory or mucous glands (AcGl), 

 the ductus ejacidatorius {EjD)^ and the penis {Pen). 



The testes of the bee {Tes) are said to be best developed in the pupa, 

 at whicli stage they form the spermatozoa. Each consists of a large 

 number of small tubules opening into a collecting reservoir at the end 

 of the vas deferens. The spermatozoa pass down through the coiled 

 vas deferens {VDef) and collect in the saclike enlargement of this 

 duct, which constitutes the vesicula seminalis {Ves). In the mature 

 adult drone these elongate sacs are densely packed with the active 

 spermatozoa, while the testes that produced them become rudimentary. 

 The vesiculae when freshly dissected appear to be alive, for they 

 bend and twist themselves about like small worms. Each opens by a 

 short duct into the base of the accessory mucous gland {AcGl) of the 

 same side. These organs have the form of two great sacs and are 

 filled with a thick, white, homogeneous, finely granular liquid, which is 

 supposed to mix with the spermatozoa as the latter are discharged. 

 The two open at the bases into the single median ejaculatory duct 

 {EjD) which opens into the anterior end of the penis {Pen) . This last 

 organ, shown in lateral view by figure 50 E, is an unusually large 

 structure in the bee and is deeply invaginated into the cavity of the 

 abdomen from the end of the ninth segment (D, Pen) as already de- 

 scribed (see page 73). While the penis is simply an ectodermal tube, 

 its walls present a number of very curious differentiations. The upper 

 part is enlarged into a bulb (fig. 50 A and E, B and PenB) having 

 two large irregular but symmetrical chitinous plates {tt) in its dorsal 

 wall, beneath which is a large gelatinous thickening (B, ss). 

 Near the base of the bulb is a double pinnate lobe (A and E, uu) 

 projecting from the dorsal wall. Below this, on the ventral side, 

 is a series of close-set, transverse plates (E, /'^'), followed again by 

 large dorsal and ventral plates {win and xx). The terminal part 

 makes a thin-walled chamber (A and E, yy), from which project 

 backward two very large membranous pouches {sz) ending in blunt 

 points. The whole tube of the penis is capable of being turned 

 inside out, and it is said that copulation is effected by its eversion 

 into the oviduct of the queen, the basal pouches of the penis {zz) 

 being forced into corresponding pouches of the oviduct, and the 

 spermatozoa in the bulb placed near the opening of the spermatheca 

 in the vagina. By their own activity probably the spermatozoa now 

 make their way up into this receptacle of the female, the spermatheca, 

 where they remain until ejected upon eggs passing down the oviduct. 

 The sjjermatozoa received from one drone normally last the queen 



