184 Beekeeping 



the individual egg cells are separated by a number of nurse 

 cells, 48 to each egg, according to Paulcke. The egg cell 

 increases in size chiefly by an accumulation of yolk which 

 serves as food for the future embryo, this yolk being supplied 

 by the nurse cells, which finally are exhausted and absorbed 

 into the yolk of the egg. The egg and nurse cells are sur- 

 rounded by an epithelium which grows thinner as the egg 

 enlarges and which finally breaks when the egg passes into 

 the oviduct. 



The egg is covered by a thin layer of chorion secreted 

 around it by the epithelial cells and the boundaries of the 

 cells may be seen in the lines which persist on the chorion, 

 forming a delicate network on the surface. At the anterior 

 end of the egg (where the head of the larva is formed and also 

 toward the head of the queen) there is a peculiar arrangement 

 of these lines, forming the micropyle. Here the spermato- 

 zoon which fertilizes the egg enters, but the mechanism has 

 not been adequately described. In most insects there is a 

 definite opening for the entrance of the spermatozoon and 

 often a complex mechanism for the closing of the opening 

 after fertilization. There is nothing so described for the 

 bee egg. 



Origin of the male sex cells. 



The organs of the male (Fig. 93) in which the male sex 

 cells originate are equally interesting. The spermatozoa 

 develop in the testes (Tes), two organs homologous with the 

 ovaries of the queen. The development of the spermatozoa 

 probably occurs almost entirely during the pupal development 

 of the drone and possibly not at all in the adult drone. From 

 the testes, the spermatozoa pass through the vas deferens 

 (VDef) into the vesicula semenalis (Ves) where they 

 collect. The seminal vesicles open into the base of the 

 accessory mucous gland (AcGl). These in turn open into a 

 single duct, the ejaculatory duct (EjD), unusually large in 

 the drone and curiously indented to conform to the structure 

 of the vagina. 



