THE HESSIAN-FLY. 



13 



A third parasite {Pohjgnotus hiernaHs Forbes)was also raised. 

 It is very small and six of them found sufficient food to pass 

 through all their metamorphoses in a single puparium of 

 the fly. In fig. 6 is shown the broken off culm, the 

 puparium of the Hessian-fl3^ and the small cocoons of this 

 minute insect still fastened to it. 



To find such numerous parasites is a very hopeful out- 

 look for those farmers upon whose fields the 

 straws containing them were gathered, and 

 it is a very good thing for the entire state 

 that these parasites are very numerous in 

 many counties infested with the Hessian-fly. 

 Straws received from other districts show- 

 fewer parasites, but not a single field was de- 

 tected in which these useful insects were en- 

 tirely absent. Their presence is easily detect- 

 ed as they make a perfectly circular hole 



Fig. 6.— Pupa- 



w"t'Ss?xfoco!fifs1rf throtigh the straw to reach the outside of 



a parasite. En- , i • • „ . 



larged. Original. thCir pnSOU; 



their prison; such holes are as large as a 

 perforation made with a sewing needle. 



To show where the puparia are located in the culm of 

 the wheat-plant, fig. 7 has been pre- 

 pared. At a are shown the puparia; to 

 the right three are exposed by remov- 

 ing the base of the leaf, and above it 

 to the left their presence over the 

 first joint is indicated by dotted lines. 

 It will be seen that the culm breaks 

 down above the infested place, and in 

 such a w^ay as to prevent the entrance 

 of moisture. 



If this dangerous insect is single- 

 brooded ill Minnesota, a point now al- 

 most definitely settled, a remedy is very 



1 1 • , 1 Fijr. 7. — Hessian-fly: at 



Simple, and, m most years, can be ap- the right three puparia(a> 



!• 1 ..1 , ," 1 u exposed; at the left pupa- 



plied without any extra expense or Jab- ria m) and the manner in 



/T>, . , 1 •! J • • j_ which steins bend and 



or. 1 he insects, hibernating in straws break. Enlarged, origi- 



usually just over the first joint, remain 



in the stubble until early spring, when they hatch and de- 



