ME TAMORPHOSIS, 
163 
a small tube, or lumen. This is the glandular part, and 
the secretion is derived from the blood by absorption 
through the surface of the cells on the outside (Fig. 59, 
A, <:), while the inner surface secretes a liquid silk, which 
fills the lumen, and is collected in the reservoir of the 
larva of four and five days old, before the time of 
spinning. At a later stage, when the spinning is 
done, the secreting portion of the gland shrinks, 
and from the inside of the propria is gradually built 
up, first the gland. System III. in the adult, and later 
Sy stein II. 
We have already seen that the drone organs are 
highly developed at a very early stage in the pupa, 
the testes being cf an enormous size. Although egg 
germs are later in making their appearance, Leuckart 
found the first traces of the internal genital organs in 
female larvae six days after the laying of the egg, and 
that at exactly this time the change of food takes place 
in the worker larvae. Those intended for queens 
receive the same food, which rapidly develops the 
ovaries, whilst the change of food in the worker 
larvae stops their development, hence we only have 
the rudimentary ovaries, already alluded to. 
The period of rest after spinning the cocoon 
varies, that of the worker being two to three days, 
drone four days, and the queen only two. The time of 
feeding the larva is generally five days for queen and 
worker, and six days for the drone. The time oc- 
cupied in the changes from the time the egg is laid to 
the time the perfect bee is ready to leave the cell is 
about fifteen days for the queen, twenty-one days for a 
