258 INSECT ORDERS 



9. The fruit flies. The tiny little banana fly is one of this group. 

 They may be found buzzing around stalks of bananas or decaying fruit 

 and vegetables. Because of their small size, ease of handling, and short 

 life cycle, they are favorite subjects for studies of heredity. 



B. Long-horned flies. 



1. Crane flies. These look like huge mosquitoes, but fortunately 

 they do not bite. They have very long fragile legs that come off quite 

 easily when handled. 



2. Mosquitoes. These are well known in nearly all parts of the earth. 

 They may even be seen coming up out of the snow as it thaws in the 

 spring in the Arctic Circle. The three main genera are: the Anopheles, 

 which spread human malaria ; Culex, which spreads elephantiasis ; Aedes, 

 which spreads yellow fever. As a group they are among the greatest 

 enemies that mankind has. The larvae, "wigglers," develop in water. 



Photo by Winchester 



Fig. 17.14. Mosquito larva. Note the breathing tube at the posterior end of the 

 body which is projected above the water for respiration. 



3. Midges. Tiny, but blood-thirsty little insects that can make life 

 miserable for man and beast alike where they are abundant. One species 

 is called the sand fly and spreads the serious tropical disease, Kala azar. 



4. Gnats. These tiny worrisome insects often form an inescapable 

 cloud around a person's head and no amount of waving and slapping can 

 drive them away. The females of many species lay their eggs in leaves 

 or twigs of plants and the plant forms a gall at the spot in which the 

 larvae develop. Some develop in mushrooms. The Hessian fly is in- 

 cluded in the group. The female lays the eggs at the node of wheat or 

 rye plants, and the maggots live between the stalk and leaf and greatly 

 curtail production since the stem usually breaks at that point. In some 

 years as much as 50 per cent of our wheat crop has been lost to this pest. 



