134 THE ANATOMY OF THE HONEY BEE. 



throughout her life, so that after mating she goes into the hive never 

 again to emerge except with a swarm, and her entire life is devoted 

 to egg laying. The drone, on the other hand, dies immediately after 

 mating, while those that do not mate are driven out of the hive in 

 the fall and left to starve. 



The spermatozoa (fig. 56 C) are minute threadlike cells, capable of 

 a vibratory motion. As found in the vesiculae, they are usually bent 

 into closely compressed loops, although many are extended to their 

 entire length. One end is blunt, but not noticeably enlarged, the 

 other is tapering, while the half toward the tapering end seems to 

 be the part chiefly endowed with the power of motion. The sperm 

 threads are contained in a liquid within the vesiculae, in which float 

 also a great number of minute granules. The vibrations of the 

 spermatozoa keep these granules in constant motion. 



2. THE FEMALE OKGANS. 



The organs of the female that produce the eggs are called the 

 ovaries (fig. 57, Ov). In insects they consist of a varying number of 

 egg tubules or ovarioles {ov) forming two lateral groups, in each of 

 which the tubules converge at both ends, the anterior ends being 

 drawn out into fine threads whose tips are connected, while the poste- 

 rior ends are widened and open into the anterior end of the oviduct 

 {OvD) on the same side of the body. An egg is simply a very large 

 cell whose size is due to the great accumulation of yolk in its proto- 

 plasm, which serves as food for the future embryo. The eggs are 

 formed in the terminal threads of the ovarioles and are at first appar- 

 ently ordinary undifferentiated cells, but as they pass downward' in 

 the tubule they increase in size at the expense of some of the other 

 ovarian cells. Hence the ovarioles usually have the form of a string 

 of beads arranged in a graded series from very tiny ones at the upper 

 end to others the size of the mature egg at the lower end. The two 

 oviducts converge posteriorly and unite into the common median duct 

 or vagina (Vag) which in most insects opens to the exterior upon 

 the eighth sternum, as already described in the general account of the 

 external anatomy of insects (see page 25), but in the bee and many 

 other insects the eighth sternum is entirely lacking as a distinct 

 sclerite, and the genital opening is therefore behind the seventh ster- 

 num and below the base of the sting. The posterior part of the 

 vagina is very large, forming a tursa copulatrix {BCpx). In addi- 

 tion to these parts there is nearly always present in insects a special 

 receptacle for the spermatozoa called the spermaiheca (Spm). This, 

 in most insects, opens directly into the vagina as it does in the bee, but 

 in some it opens into the roof of the genital chamber above the eighth 

 sternum, when this is present, by a separate orifice behind that of the 



