ENTOMOLOGICAL. 



71 



upset, and which can float upon the stream without injury 



until the vivifying sun brings them all to life. Our objects, 



remember, are the pupa and the larva, both intermediate 



states of the creature. 



The larva, which I will 



show you, bears very 



little resemblance to the 



pupa, and neither the 



slightest resemblance to 



the life which is to come 



of them. Here is a true 



likeness of the former (fc), 



beside another of the 



latter (a). 



Observe at A a small 

 pipe extended: I know 

 only a few animals that 

 breathe through the tail. 

 At B is seen the com- 

 mencement of the breath- 

 ing-tubes, which convey the air to all parts of the body 

 Its chief business in life number one is to eat, it has 

 nothing else to do ; its food is whatever it can find in the 

 water in which it lives. It throws off its exterior covering, 

 its outer skin, or jacket we may call it, several times 

 before it passes into its mummy form, when it becomes 

 entirely changed. Its eating-time is now over, and the 

 object we are looking at is that which I am describing. 

 Not partaking of food, it has no digestive organs. Its 

 organs of respiration are likewise changed: it has lost 

 the little tap-like tail with which it came to the surface ; 

 yet, filling its body with air by jumping up to the sur- 

 face, it repeats its leap for a similar purpose every time it 

 needs a fresh supply, and then it breathes through the 



Larva of the gnat. 



A, entrance of the air- 

 pipe ; B, the tracheae. 



Pupa of the gnat. 



