56 HUMBLE CBEATURES. 



lifetime^ and whose abdomen is necessarily filled with 

 an immense number of eggs (PI. VIII. fig. 1)^ the 

 large respiratory sacs are quite wanting, and the only 

 air-vessels are the larger and smaller trachese. 



But by far the most remarkable feature in con- 

 nexion with this portion of the Bee^s anatomy is the 

 structure of the tracheal tubes themselves. On exa- 

 mining one of these under the microscope (PI. VII. 

 fig. 4)j you will find it to consist of a double mem- 

 brane supported between the two folds by a coil of 

 hair-like fibre, just as the coil of wire gives strength 

 to the elastic gas-tubing employed to feed a table- 

 lamp from an ordinary chandelier. The object of 

 this arrangement is similar in both cases : the trachese 

 are rendered very elastic, and any hindrance to the 

 passage of air by their collapse is only momentary, 

 as the supporting coU reopens the tube as soon as 

 the external pressure is removed. A close investi- 

 gation of this mechanism shows that the fibrous coil 

 becomes more and more delicate as the trachese di- 

 minish in size, and that it is not continuous, but 

 here and there a new coil commences between the 

 folds of the preceding one. 



Dismissing now this interesting portion of the Bee's 

 anatomy, we shall direct our attention to the nervous 

 and circulating systems, and we must commence by 

 remarking that in the Bee, as in all other articulate 

 animals, the relative position of these two systems is 

 precisely the reverse of what it is in the higher ani- 

 mals. In the latter (taking ourselves as an example). 



