Bui. 808, U. S. Dept. of Asriculture. 



Plate I. 



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JoiNTwoRM Flies of the Genus Harmolita. 



A, Comparative yields from healthy wheat plants and those infested with the joint worm (Harmo- 

 lita tritici); reading from left to right, the yield from 85 uninfested stems, 85 stems with one node 

 infested, 85 stems with two nodes infested, and 85 infested fallen straws. The heads were all 

 measured against each other, so that, for example, any head from the lot of uninfested plants had 

 a corresponding head of equal length in all the infested lots; B, Field badly infested with the 

 jointworm. Note the large percentage of fallen straws. 



