Class of the Honey-Bee, 23 



lowest, simplest, Protozoan branch, which includes ani- 

 mals often so minute that we owe our very knowledge of 

 them to the microscope, and so simple that they have been 

 regarded as the bond which unites plants with animals. 



THE CLASS OF THE HONEY-BEE. 



Our subject belongs to the class Insecta, which is mainly 

 characterized by breathing air usually through a very com- 

 plicated system of air tubes. These tubes (Fig. i), which 

 are constantly branching, and almost infinite in number, 



Fig. I. 



A Trachea, magnified. 



are very peculiar in their structure. They are composed of 

 a spiral thread, and thus resemble a hollow cylinder formed 

 by closely winding a fine wire spirally about a rod, so as to 

 cover it, and then withdrawing the latter, leaving the wire 

 luimovfd. This spiral elastic thread, like the rings of car- 

 tilage in our own trachea, serves to make the tubes rigid ; 

 and like our trachea — wind-pipe — so these trachae or air- 

 tubes in insects are lined within and covered without by a 

 thin membrane. Nothing is more surprising and interest- 

 ing than . this labyrinth of beautiful tubes, as seen in dis- 

 secting a bee under the microscope. I have frequently 

 detected myself taking long pauses, in making dissections 

 of the honey-bee, as my attention would be fixed in admi- 

 ration of this beautiful breathing apparatus. In the bee 

 these tubes expand in large lung-like sacs (Fig. ^,f), one 

 on each side of the body. Doubtless some of my readers 

 have associated the quick movements and surprising activ- 

 ity of birds and most mammals with their well developed 



