GLAND STRUCTURE. 
119 
together, sometimes they have spaces between them 
like those in the intercellular type. The cell layer 
{d ) which surrounds these, disappears near the bend. 
This gland, although large in the 
worker, is enormous in the queen, 
the cell layer is much more de- 
veloped, and the openings of the 
more numerous canaliculi are set 
closer together, being surrounded 
by hairs. In the drone there is 
only a trace of this gland, the sac 
being very small, having a differ- 
ent structure, and the intima ap- 
pearing in folds. The secreting 
cells are usually absent, or they 
are so shrunken that they are not 
capable of producing secretion. 
Schiemenz says that System 
II., and in part System III., are derived from the 
spinning glands in the larva, whilst the others are new 
structures. The spinning glands will be described 
in the chapter on ‘Metamorphosis’ (P^g^ 162). 
Summary. 
Having now described the glands and digestive 
system, we will endeavour to study their functions. 
The various functions ascribed to the glands are : The 
production of a secretion to assist digestion, to convert 
the cane sugar of nectar into the grape sugar of honey 
(Planta), for the elaboration of wax (Planta), and for 
the production of brood food, or for queen-feeding 
Fig. 5 1. — Gland. 
System IV. 
