50 AUSTRALASIAN 
sacs in the case of the worker, and it will be seen at a oe 
that they take the places of the smaller air sacs 4, and of the 
ovary }, in the case of the queen (Fig. 11). 
Fig, 11. AIR SACS AND OVARIES Fig, 12,_AIR SACS OF THE 
OF QUEEN, WORKER. 
a. Air sack; b. Ovary. 
Every person accustomed to bees must frequently have — 
observed that some of the workers, when returning from the 
field, remain for some time on the alighting-board before 
entering the hive, and that during that time the rings of the 
abdomen are in constant motion. These bees are simply 
breathing themselves after along and tiresome flight. Mr. 
Cheshire remarks :— 
“The constant elongation and contraction of the abdomen of the 
bee’s body has for its object the ejection of air which has become car- 
bonised and the drawing in of fresh supplies. The spiracles admit of 
being closed voluntarily. When the bee is in flight with the air sacs 
filled, if the spiracle be closed and the abdomen contracted, the faeces 
are extruded. This explains why bees never soil their hives, except 
