OR, MANUAI< OF THB APIAgY. 87. 



the wire unmoved. This spiral elastic thread, like the ring-s 

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

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

 in insects are lined within and covered without by a thin 

 membrane. Nothing is more surprising and interesting than 

 this labyrinth of beautiful tubes, as seen in dissecting 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 admiration of this beautiful 

 breathing apparatus. In the bee these tubes expand in large 

 lung-like sacs (Fig. i,/), one on each side of the body. . Doubt- 

 less some of my readers have associated the quick movements 

 and surprising activity of birds and most mammals with their 

 well developed lungs, so in such animals as the bees, we see 

 the relation between this intricate system of air-tubes — their 



Fig. 35. 



A Trachea, magnijied. — Original. 



lungs — and the quick, busy life which has been proverbial of 

 them since the earliest time. Along the sides of the body are 

 the spiracles or breathing-mouths, which vary in number. 

 The full-grown larva has twenty, while the imago has seven 

 pairs ; two on the thorax — one on the prothorax, and one on the 

 metathorax — and five on the abdomen. The drone has one more 

 on each side of the abdomen. We see, then, that to strangle an 

 insect we would not close the mouth, but these spiracles along 

 the sides of the body. We now understand why the bee so 

 soon dies when the body is daubed with honey. These spiracles 

 are armed with a complex valvular arrangement which ex- 

 cludes dust or other noxious particles. From these extends 

 the labyrinth of air-tubes (Fig. 1,/,/, 27 t, t), which carries 



