WHEAT FLIES — THEIR ABUNDANCE. 297 



hoped that some one who is conveniently situated for testing the 

 efficacy of this measure, will do so, and make the result known 

 to the public. 



Burrowing in different parts of the stalks, rendering them dwarfish and often 

 causing the heads to perish; small, slender, pale-green and watery-white 

 shining maggots. 



The larvae of several small wheat flies and barley flies of the genera 

 Chlorops, (plate 1, fig. 4), and Oscinis (plate 1, fig. 5). 



In Europe it has long been known that among the worst depre- 

 dators upon the grain crops there, are the larvse of several small 

 flies belonging to the genera Chlorops and Oscinis. Some of these 

 attack the young plants, and taking their station slightly above 

 the root destroy the central stalk. Others burrow in the stalk 

 or straw, and others infest the heads. Thus every part of the 

 plant finds an enemy in one species and another of this group of 

 insects. And so seriously do they injure the crops on which 

 they prey, that Linnaeus a century ago computed the loss occa- 

 sioned by one of them {Chlorops Frit), which infests the heads of 

 barley in Sweden, to amount to nearly half a million of dollars 

 annually. 



It has not hitherto been known that the wheat in this country 

 was attacked by any insects of this kind. But I have the pre- 

 sent season discovered these small flies in abundance, in every 

 wheat field in my neighborhood. On sweeping with a net any- 

 where among growing wheat, a multitude of them will be 

 gathered. They are of several different kinds and all appear to 

 be of species distinct from those described in the works of Mac- 

 quart, Zetterstedt, and other European writers to which I am 

 able to refer. And upon examining the wheat stalks at different 

 times during the season, the larvse of one and another of these 

 flies are found therein — smooth, shining, footless little maggots, of 

 pale green and watery-white colors, commonly imbedded in the 

 straw in small burrows or cylindrical channels which they have 

 excavated. 



As these flies appear to be native species, it is probable that 

 before wheat was cultivated upon this continent they sustained 



