136 THE ANATOMY OF THE HONEY BEE. 



vagina. In the bee the tAvo poison ghinds {xiGl and BGl) do not 

 open into the vagina but, as already described, into the base of the 

 sting. They are. hence, probably special organs having no homo- 

 logiies in nonstinging insects. 



The ovaries of the queen bee form two large gourd-shaped masses 

 (fig. 57, Ov) whose posterior or basal ends are enlarged and whose 

 anterior ends are narrowed, curved, and attached to each other. 

 Since the queen lays eggs continuously during her entire life the 

 ovaries always contain eggs in all stages of growth, and conse- 

 quently do not vary so much in appearance as the}^ do in those insects 

 that ripen only one lot of eggs and deposit these all at one time. 



The structure of the ovarioles and the formation of the eggs in the bee 

 have been si^ecially studied by Paulcke (1900) and the following is 

 a resume of his paper : The terminal threads of the ovarioles are 

 covered by a thin tunica propria and are^ filled with a protoplasmic 

 mass containing transversely elongate nuclei in a single close series, 

 but no cell outlines. Farther down, in the upper end of the ovariole 

 proper, the nuclei become arranged in two rows, while here also the 

 cell boundaries begin to appear; still farther along, where the cells 

 are clearly defined, the latter become differentiated into epithelial 

 cells and germ cells. Next, the germ cells themselves divide into 

 ^gg cells and food or nurse cells. When first formed the Qgg cells 

 occur in any part of the diameter of the tube, but they soon become 

 arranged in a row down the middle of the ovariole and are separated 

 by groups of nurse cells. The epithelial cells at this time arrange 

 themselves on the periphery just within the tunica propria, but 

 farther down they form a capsule or follicle about the &gg and, less 

 definitely, about the group of nurse cells at its upper end. The upper 

 end of the Qgg becomes narrowed by a constriction of the epithelial 

 capsule, which, however, does not shut it off from the nurse cells, 

 a connection being retained with the latter in the form of a neck 

 from the Qgg abutting against them. There are 48 of these nurse 

 cells to each Qgg. which fact is accounted for by supposing that each 

 original germ cell divides into 4, one of which ceases further divi- 

 sion and becomes the Qgg cell, while each of the other 3 divides into 

 16 by four consecutive divisions. The latter are the nurse cells and 

 their function is to nourish the o-gg cells. They persist down to 

 the time when the egg is fully formed, when they suddenly disappear 

 by being absorbed bodily into its yolk. Toward the end of the 

 growth of the egg the follicle cells become thinner and thinner, so 

 that when the Qgg is ready to go into the oviduct it has but a thin 

 membrane to break through. 



The organs of most especial interest to the student of the bee are the 

 spermatheca and the a]:)paratus by means of Avhich the queen is able 

 to dole out the spermatozoa to the eggs as she deposits the latter. 



