DIPTERA OF MINNESOTA. 107 



brownish and much resemble the puparia of the Hessian Fly, treated 

 of elsewhere in this report. For this reason, but more particularly 

 from the fact of the bending or breaking of the stem, this insect's 

 work is sometimes mistaken for that of the Hessian Fly. However, 

 it has been the observation of the writer that the Hessian Fly in Minne- 

 sota out-numbers the Frit Fly 10,000 to i, and hence this mistake is 

 not often made. As far as we know, this pest passes the winter as 

 a pupa in the stem in the stubble field, and hence the same remedies 

 would apply here as in the case of the Hessian Fly. If a farmer has 

 reason to suspect the presence of this pest in his stubble field, by noting 

 bent straws left by the reaper, he need only split the straw with a 

 penknife to the joint just below the bending to settle the doubt, for 

 if this insect has caused the bending, the puparium will be seen at the 

 joint and inside the stem, the interior of the stem being generally dis- 

 colored also. Whereas, in the case of the Hessian Fly, which causes 

 the same injury, the puparium, or "flax ^eed," will be found outside 

 the stem, between it and the sheath. 



The name "Frit Fly" is given to this insect because Swedish 

 farmers apply the term "frits" to wheat rendered worthless by its 

 attacks. , 



As mentioned above, this fly caused considerable damage in Minne- 

 sota in 1892. Like other pests of similar habits, it appears in increas- 

 ing numbers at one period, and then almost disappears, to occur again 

 later. 



The second wheat pest referred to, Meromyza americana, is 

 reported to the Experiment Station from time to time. In 1895 ^^ 

 was reported numerous in the Red River Valley, and at points in 

 central and eastern Minnesota. In 1896 it was also present in con- 

 siderable numbers. In that year, too, it was common in the wheat 

 at the Experiment Station farm. On affected grain, the heads, instead 

 of filling normally, turn white, and are called "white heads" or "bald 

 heads." 



Fitch described this insect in America as early as 1855, but 

 existing records indicate that it was known as a wheat pest in Pennsyl- 

 vania as early as 1821, Webster and Forbes worked up this insect 

 a number of years ago, in Ohio and Illinois, and claimed at that time 

 three annual broods for each state, with the probability of more in 

 states farther south. In Minnesota where we have but little fall 



