EEPOET OF OBSEBVATIONS UPON INSECTS AFFECTING 



GRAINS. 



By F. M. Webster, Special Agent. 



LETTER OF SUBMITTAL. 



» 



La Fayette, Lnd., December 14, 1889. 

 Sir: I herewith transmit my annual report of observations on insects affecting 

 cereal grains, made under your direction, during the current year. A more elaborate 

 report, treating of the destructive grain insects of the United States, to be prepared 

 jointly with yourself, is nearing completion, and thepresent report is submitted now, 

 in order to avoid the necessity of including details in the more important work to 

 follow. As usual, lam under many obligations for the determination of specimens 

 and numberless other courtesies. 

 Respectfully, submitted. 



F. M. Webster. 

 Prof. C. V. Riley, 



U. S. Entomologist. 



THE WHEAT STRAW WORM. 



(Isosoma tritici Riley.) 



These insects have not been observed by me in any great numbers 

 since they were last treated in my reports, and the species is only men- 

 tioned in order to record the occurrence of a female of the wingless 

 spring form, on the 18th of July, in a field of wheat. 



THE WHEAT STEM MAGGOT. 

 {Meromyza americana Fitch.) 



Since the establishment of the fact of a summer brood originating 

 during the month of August, and largely, it is supposed, in volunteer 

 wheat, considerable emphasis has been placed upon the destruction of 

 this illegitimate growth, of grain. There has, however, been pretty 

 good cause for believing that the insect developed also in other plants, 

 and this season we have reared the adult from Blue grass, Poa pratensis, 

 during the latter part of August. 



Since the discovery of the species there has been nothing placed on 

 record relative to its discrimination between varieties of wheat, or 



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