150 THE ECONOMIC IMPORTANCE OF ANIMALS 



b. The Larva (Wiggler) 



Materials. The eggs will hatch if kept in a warm place, or 

 wigglers can be scooped from a pond or pool of water. These 

 may be kept in a screened battery jar half full of water. 



Observations. What is the shape of the larvse? How do 



they move through 

 the water? Watch 

 the larvse while at the 

 surface. Which end 



is up? (Note the 

 breathing tube that 

 reaches through the 

 surface of the water.) What is the position of the larvse while 

 at the surface? If they lie horizontal to the surface, they are 

 the larvse of the anopheles, the malarial mosquito ; if at an acute 

 angle, the larvse are those of culex, the harmless mosquito. 



c. The Pupa 



Method and Observations. Place a number of wigglers in a 

 screened battery jar. Allow them to cast off their skins and 

 become pupse. How does 

 this stage differ from the 

 larval stage? Notice the 

 empty shells of the pupse 

 floating on the surface of 

 the water. How did the 

 adult mosquitoes get out? 

 Do the pupse come to the surface of the water? If so, why? 

 Compare the position of the pupse at rest with the figures. Is 

 the mosquito a culex or an anopheles ? 



d. The Adult 



Observations. In a hatched adult observe the number and 

 kind of wings. In which insect group do mosquitoes belong? 

 Notice the antennse or feelers. (The males have more bushy 



