BEE MANUAL. 49 
In this engraving details of only one side are shown, and 
only one air sac on that side. 
Fig, 1.—_RESPIRATORY ORGANS OF THE BEE. 
AIR SACS OF BEE. 
There are however, in the worker bee, two sacs on each side 
a large and a small one; and, what is very remarkable, the 
larger sac is in fact the undeveloped ovary of the insect, and in 
the queen bee is replaced by the ovary proper, so that she 
possesses only one small air sac on each side. ‘The large air 
sac of the worker is only distended during the time of flight, 
and we may notice in this substitution of a valuable auxiliary 
to the flight and carrying power of the worker bee, in place of 
an organ not required by her, a beautiful adaptation of 
means to the end. The queen we know is not required to fly 
far or often, and then not to carry any loads of honey or 
pollen—indeed it is a well-known fact that she cannot fly far, 
when her ovaries are filled with eggs, and the smaller air sacs 
therefore are sufficient for her purpose. The following diagrams 
show (in Fig. 12) the arrangement of the large and small air 
E 
