166 THE LIFE OF AN INSECT. 



an air-pump, which forces down fresh air, and so 

 enables the man to breathe almost as comfortably 

 as if he were walking on land, instead of at the 

 bottom of the sea. Let it be conceived now that 

 there were no air-pump at the top of the hose, 

 but simply a buoy of cork to keep it floating, and 

 that the diver had the power of shortening or 

 lengthening the hose at his pleasure, we should 

 then have a tolerably fair representation of the 

 contrivance with which Infinite Wisdom has sup- 

 plied the humble creatures of whom we are about 

 to speak. 



By carefully examining the water running from 

 manure heaps, or water which has become putrid, 

 and is much loaded with mud and ooze, the reader 

 will pretty generally be successful in discovering 

 a number of the larvae of a two-winged fly of 

 the shape represented in the cut. When dis- 

 covered, the singularity of their structure will 

 amply repay him for the trifling unpleasantness 

 attending the search after them. After washing 

 them in a little fair water, and putting them into 

 a tall ale-glass, or German beer-glass, which must 

 be three parts filled with water, they will be in 

 the best condition for our examination. When 



