THE REPHODUCTIVB SYSTEM. 137 



The spermatheca consists of a globular seminal sac (fig. 57, Spm), 

 of a pair of tubular accessory glands (SpmGl) , and of a duct whose 

 upper end is connected with the sac and receives also the duct of the 

 glands,' and whose lower end opens into the anterior part of the 

 dorsal wall of the vagina just caudad of the united bases of the 

 oviducts. 



The spermatozoa are discharged by the male into the upper end 

 of the vagina, and in some manner they make their way up into the 

 sperm sac through the duct. Cheshire (1885) described the latter 

 as forking toward its lower end into an anterior branch which opens 

 into the vagina and into a posterior branch which turns backward 

 and becomes lost in the lower end of the vaginal wall. This second 

 branch he believes is open in the young queen and is the one through 

 which the spermatozoa enter the sac. Breslau (1906) has shown, how- 

 ever, that Cheshire was entirely wrong in his supposed observation 

 of the forking of the duct, that the latter is a single tube, and that 

 consequently the spermatozoa must both enter and leave the sac by the 

 same conduit. It used to be supposed that the sperm sac had muscular 

 walls and that it forced the spermatozoa out as from a compressed 

 bulb, but Breslau has shown that this also is a mistaken notion, that 

 the walls of the sac are entirely devoid of muscular fibers, and that 

 the spermatozoa are sucked out by a muscular apparatus in the wall of 

 the duct, which structure he names the sperm pump. Cheshire (1885) 

 had previously described this apparatus in a very imperfect manner 

 without recognizing any pumping function, for he supposed that 

 by the relaxation of certain muscles the spermatozoa simply passed out 

 of the sac and went down the tube. Breslau says, however, that 

 the spermatozoa have not enough energy of their own to come out of 

 the sac and, hence, do not need to be kept in by a special sphincter 

 muscle, as described by Leydig. 



The upper end of the spermathecal duct makes an S-shaped bend 

 jugt beyond the opening of the sac, and a number of muscles dis- 

 posed upon this part constitute Breslau's sperm-pump. Breslau shows 

 that a contraction of certain of these muscles flattens the bend of 

 the S and causes an enlargement of the lumen of the upper end of 

 the loop. This, therefore, sucks into itself a small bundle of sperma- 

 tozoa from the sac. The contraction then of other muscles forces 

 the rest of the sperm-threads back into the mouth of the sac and 

 drives the small bundle thus cut off down through the duct and into 

 the vagina. Moreover, Breslau claims that this explanation is not 

 theory only, for, by preparing histological sections from queens 

 killed at different moments of eggrlaying, he procured specimens 

 showing the various stages in the pumping process and in the passage 

 of the sperm through the duct. Cheshire calculated that a normal 

 queen lays 1,500,000 eggs in her lifetime and that the spermatheca 



