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increased size, and tlie enlargement of the stem cause them to be im- 

 bedded in the stalk, which generally breaks off in the places thus in- 

 jured. Whole fields are sometimes destroyed in this way. The larva 

 of these flies remain in the ground all winter, sometimes attached to 

 the stems, and sometimes buried in the soil. 



Harrowing in the spring is an effectual chech to the Hessian fly, as 

 the larva are torn up and exposed to destruction, whilst rolling crushes 

 those that are attached to the stems. 



A rotation of crops has a tendency to destroy all wheat insects, as 

 - the young are exposed to destruction by the cultivation of drill crops. 



The wheat fly, (cecidomyia tritice) is another troublesome enemy to 

 the farmer. Its history has been investigated by Kirby and several 

 other intelligent entomologists. The parent is a small fly, shaped like 

 a mosquito, but of an orange color, with wings rounded at the tips and 

 fringed with hair. The female is furnished with a retractable oviposi- 

 tor, four times as long as the body, with this she deposits her eggs in 

 the husks of the flowers ; the worms are produced from the eggs in a 

 ■week, and feed upon the young grain, which is suitable nourishment 

 for them so long as it continues in a milky state. As many as forty of 

 these minute orange-colored worms have been found in one husk. Of 

 course the grains thus attacked are generally completely destroyed, or 

 rendered shrivelled and worthless. 



The wheat fly usually makes its appearance when the ears are com- 

 mencing to shoot out, and attacks them as they emerge from the sheaths. 

 We may observe that during the first few days of their appearance, 

 only one side of the ear is visible, consequently the attacks of the fly 

 are confined to one side of the ears ; and this is the reason why so 

 much wheat is to be seen with one side of the ears damaged, and the 

 other quite safe. 



From this circumstance, we may perceive the reason why a thick, 

 ■even ripening crop generally escapes the ravages of the fly, better than 

 a thin, uneven one. In the first case the wheat shoots out strong, and 

 gets ahead of the fly; in the latter the ears come out slowly and at dif- 

 ferent times, according to the first or second growth of the stems, and 

 are cut oft" in detail. 



The fly is found longer on spring wheat, than on that which has been 

 sown in the fall. It seems to feed on a kind of gum which adheres to 



