118 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



1779, near where the Hessian troops had landed three years before. 

 It now occurs over the main wheat-growing area of the eastern 

 United States between parallels 35 and 45 westward to the 100th 

 meridian, on the Pacific coast, in Canada, and in many other parts 

 of the world where wheat is grown. Not infrequently it destroys 

 25 to 50 per cent of the whole crop in some localities, and it has 

 been estimated that 10 per cent of the crop of the whole country 

 is lost from its ravages. 



Life History. The adult flies are little dark-colored gnats about 

 one-tenth inch long, so small as to escape common observation. 

 Each* female lays 100 to 150 minute reddish eggs, one-fifteenth 



inch long, placing 

 them in irregular 

 rows of from three 

 to five or more, 

 usually upon the 

 upper surface of the 

 leaves. In a few 

 days these hatch 

 into small, reddish 

 maggots, which 

 soon turn white, are 

 cylindrical, about 

 twice as long as 

 broad and have no 

 true head or legs. 

 The fall brood mag- 

 gots burrow be- 

 neath the sheath of 

 the leaf and its base, 

 causing a slight en- 

 largement at the point of attack, but in the spring they usually 

 stop at one of the lower joints, in both instances becoming fixed 

 in the plant, absorbing its sap and destroying the tissues. The 

 first indications of the work of the maggots on winter wheat in 

 the fall are the tendency of the plants to stool out, the dark 

 color of the leaves and the absence of the central stems. Later 

 many of the plants yellow and die. The spring maggots attack 

 the laterals, or tillers, which have escaped the previous brood, 



FIG. 99. The Hessian fly, adult male greatly en- 

 larged. (After Marlatt, U. S.Dept. Agr.) 



