BEE MANUAL. 



49 



In this engraving details of only one side are shown, and 

 only one air sac on that side. 



Fig. 10,— 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 fiy 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 .arrangeiment of the large and small air 



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