The Life Processes of the Individual 135 
is concave on the posterior surface to fit the rounded thorax. 
The three ocelli (0) in the worker are arranged in a triangle 
at the top of the head, the antenna; {Ant) arise from the 
center of the face. On the posterior surface is the foramen 
magnum {For) through which pass nerves, 
oesophagus, dorsal blood vessel and tra¬ 
cheal tubes connecting the head and 
thorax. Below the foramen magnum is 
the fossa {PrbFs) where the proboscis 
is attached. 
The heads of the queen and the drone 
differ from that of the worker in size and 
shape (Fig. 69, A, B and C). The face 
of the queen {B) is more nearly round 
and is relatively wider. That of the 
drone (C) is larger and nearly circular, 
this being due to the unusual develop¬ 
ment of the compound eyes {E) which 
meet at the vertex of the head, crowd¬ 
ing the ocelli (0) to the front near the 
bases of the antennae. The head of the 
queen is smaller than that of the worker. 
The mandibles (Fig. 68, A, Md) or 
jaws, which are of special interest to the 
beekeeper, are situated on the sides of 
the mouth anterior to the base of the 
proboscis, being attached to the clypeus 
{Clp) and the postgena {Pge) by two 
articulations, so constructed that they 
serve only to crush or bite food and 
not to grind it. The mandibles of in¬ 
sects, when present, work sidewise and 
not up and down in a median plane, as do our jaws. The 
mandibles of the three types of bees differ in shape and size. 
Those of the worker (Fig. 70, A) are hollowed out and have 
smooth and rounded edges, while those of the drone (Fig. 70, 
B) and of the queen (Fig. 69, B) are pointed anil notched. 
O 
Fig. 69. — Anterior 
view of heads of 
worker (A), queen 
(B) and drone (C), 
with front, anten- 
nee and proboscis 
removed from each. 
