49 
CHAPTER VII. 
INTERNAL STRUCTURE. 
Endo-skeleton — Mesocephalic Pilla7's — Cori'ugatio7is of Thorax 
— Mesoph rag77ia. 
Although we stated at page 15 that the bee had 
neither bones nor cartilaginous framework, the skeleton 
is not entirely external. There are braces of chitine, 
corrugations and webs of the same material, which 
strengthen weak parts. These are called the endo- 
skeleton, Macloskie (105), who has studied the in- 
ternal skeleton of the head, found the clypeus bent 
down at its posterior edge into a hard transverse ridge, 
with thick outgrowths at the posterior angles. From 
these outgrowths descend pillars (called meso-cephalic) 
obliquely from the front to the back of the head. 
These pillars (Fig. 23, Ji) are inserted in the back of 
the skull close to the opening (z^). 
Fig. 24 is a diagram of the transverse section of 
the skull, showing the disposition of the endo-skeleton. 
The clypeus has to support the mandibles and to 
E 
