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 micropylc. 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 (Fes) 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. 
