THE BEE. 55 



In explanatioiij however, it is necessary to remark 

 thatj although only one set of organs is here de- 

 lineated, they are bilateral, that is to say, distributed 

 in pairs symmetrically on either side of the body. 

 The largest pair of sacs is found in the abdomen 

 (PI. VII. fig. 3, a) ; from these proceed two main 

 trunks, the one {b) upwards into the thorax, and the 

 other (c) down to the termination of the abdomen. 

 The latter gives out large branches ending in sacculi 

 or little sacs {d), whilst the tubes that pass up- 

 wards (6) traverse the thorax in a straight line with- 

 out any ramification whatever, and only in the head 

 do we find a second pair of sacs («') of considerable 

 dimensions. You will see, therefore, that the greater 

 number of the respiratory vessels are to be found in 

 the head and abdomen, especially in the latter, and 

 the reason for this arrangem.ent is simple and in- 

 structive. The abdomen contains all the viscera, and 

 is by far the heaviest part of the body ; it has there- 

 fore the greatest need of the inflated air-vessels to 

 give it support, and to some extent this applies also 

 to the head with its large solid eyes, whilst the thorax 

 is effectually buoyed up in the atmosphere by the 

 powerful double wings : thus, you see, the equili- 

 brium is maintained throughout every part of the 

 body. 



Not only has Nature been thus far consistent in 

 the disposition of the respiratory vessels, but we find 

 that in the queen-bee, which quits the hive and takes 

 her flight in the air only twice or thrice during her 



