DIPTERA 



117 



Fig. 48. — An adult yellow fever mosquito (from Howard). 



The rudiments from which these parts of the fly will all 

 later develop are present within its body, and along with 

 them there is a great store of soft white fat that will furnish 

 the materials 

 out of which, 

 during the pupal 

 period, all these 

 parts will be 

 formed. 



When the 

 larva is fully fed 



it leaves the pulp, and burrows into the soil. There its skin 

 shrinks and hardens into a brown capsule-like case, called 

 a pupariurn, (plural puparia) within which the pupa is 

 formed. The pupa is soft and white, and carries the legs, 

 wings, antennae, etc., that have suddenly appeared at the 

 last molting. The pupal stage lasts several weeks. Then the 



adult flies emerge 

 and scatter, and 

 feed and mate 

 and lay eggs. 

 They may live 

 several months. 

 The most 



Fig. 49. — The larva of this mosquito (from Howard). aKnnrlanr anrl 



most familiar flies are of this type: the house-fly, for example, 

 whose larvae live in stable manure; also, these pests of our 

 fields and gardens, whose larvae are known as "root 



