8 THE FRIT-FLY. 



shading to yellowish-brown toward the smaller end. If 

 closely inspected it showsfaint traces of sutures or segments. 

 The illustration (fig. 2) shows the different stages of the 

 insect far better than words can describe them. These seed- 

 like objects contain at this time (Oct.) whitish larvee, or 

 worms; and no pupae have been detected inside of them up to 

 this date. The larva, or worm, is also illustrated in fig. 2, 

 1> ; it is of a greenish-\vhite color when alive and just removed 

 from the culm. 



These puparia'are very similar to those of the Hessian-fly 

 in its "flax-seed stage" and their resemblance has given 

 color to the belief that this injurious insect had found a 

 home with us, which unfortunately proved true, as will be 

 shown later. Judging from the fact that onlj^ pupae can be 

 found at this time it would appear as if this insect hibernates 

 in that stage. This is really the only one in which it could 

 well pass our northern winters, being in that stage well pro- 

 tected by its old and thickened skin and by the stem of the 

 plant. The puparia are inserted in the material of the upper 

 part of the node, inaccessible to any moisture from the out- 

 side, as the stem above does not break off entirely but sim- 

 ply bends in a more or less acute angle a short distance over 

 them, thus preventing the entrance of water. Yet the culm 

 is sufficiently fractured to permit a free exit of the future fly 

 in spring. 



As shown in the following question from Bulletin No. 

 23, the insect is not an entire stranger in Minnesota: "It 

 is not always easy or even possible to explain why 

 any one insect should suddenly appear in large numbers 

 over an extended area. It is only by a very careful and 

 long continued investigation that we may sometimes arrive 

 at a true explanation. Here it is readily found in the fact 

 that owing to the w^et autumn of 1891, and the equally wet 

 spring of 1892, not much more than one-half of the usual 

 acreage of wheat was plowed, and in many places the shocks 

 of grain had to be left upon the fields. Many inquiries plain- 

 ly indicated that in 1891 small patches of wheat had been 

 noticed which showed bleached heads long before harvest, 



and no doubt these white culms harbored the insect 



un- 



