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INSECTS DIPTEKA DIAGRAM 6 



round its body tlie cocoons in which they undergo their 

 metamorphosis. 



The Cynipidoe are other small Ilyinenoptera in which the 

 ovipositor instead of being straight, as in the Ichneumons, is 

 spirally rolled. The ichneumons are serviceable to man by 

 destroying caterpillars ; and the cynipidee are also useful animals, 



Gall nut. Cynips of Cynips magnified, 

 the ink-gall. 



but in a different way. They pierce the leaves of trees to lay 

 their eggs there. Where they have pierced the plant, a gall is 

 produced. When it is carefully opened, we always find a 

 number of the larvee of the cynips in the middle. In some 

 countries a great trade is carried on in these galls, because they 

 are used for making black ink. Those which are sold under the 

 name of gall-nuts are produced by a cynips which pierces the 

 leaves of a kind of oak. 



OEDEE DIPTEEA. 



This may be known immediately by the insects which compose it 

 having but two wings ; they have also no jaws but only a 

 proboscis or a sucker. 



The gnats and mosquitoes live near water, and lay their eggs on 

 its surface; the eggs are joined together in regularly shaped 



