47 
CHAPTER VI. 
THE ABDOMEN. 
Of Worker — Petiole — Rings — Pygidium — Dorsal and Ventral 
Plates — Expansion and Contraction — Wax Plates — Leiigth 
in Queen and Droiie, 
The abdomen of the worker, which is connected to 
the thorax by a very short petiole (Fig. 22, 
is made up of six imbricated rings of chitine, which 
gradually diminish in size towards the ^n(l{pygidii/ 7 ?i^g). 
Each of them is made up of two plates; the dorsal^ or 
those on the back, are the largest, and overlap the 
smaller ventral plates found on the under side. Each 
of these rings is connected with the next by means of 
a thin chitinous membrane, which, by creasing, allows 
one plate to pass over the other, and at the will of the 
insect the abdomen can be expanded or contracted. 
The dorsal plates are fringed with hairs. The first 
ventral plate is small and rounded off at the upper 
edge, whereas the last one is heart-shaped, and those 
between the two are shaped somewhat like a saddle, 
and slightly convex on the outside. In these four 
plates (c, d^ e^ f) the exposed part consists of hard and 
dark-coloured chitine, and the part which is covered 
is much thinner. It has a framework of hard chitine, 
which encloses on each side two five-sided perfectly 
clear transparent surfaces, on which the plates of wax 
are formed. The uncovered parts of the eight scales 
