150 THE ECONOMIC IMPORTANCE OF ANIMALS 



b. The Larva (Wiggler) 



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

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

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



Observations. — What is the shape of the larvae? How c 



they move throu^ 

 ;ni^,-.,»^_^^^„,..<-<^J^^ the water? Wat< 

 ^ ,VA4tt,uuJ^W1^:^■y^ *^6 lawse while at tl 



is up? (Note tl 

 breathing tube th, 

 reaches through tl 

 surface of the water.) What is the position of the larvae whi 

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

 the larvae of the anopheles, the malarial mosquito ; if at an acu 

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



c. The Pupa 



Method and Observations. — Place a number of wigglers in 

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

 become pupae. How does 

 this stage differ from the 

 larval stage? Notice the 

 empty shells of the pupte 

 floating on the surface of 

 the water. How did the 

 adult mosquitoes get out? 

 Do the pupae come to the surface of the water? If so, whj 

 Compare the position of the pupae at rest with the figures, 

 the mosquito a culex or an anopheles ? 



d. The Adult 



Observations. — In a hatched adult observe the number ar 

 kind of wings. In which insect group do mosquitoes belong 

 Notice the antennae or feelers. (The males have more busl 



