THE HESSIAN-FLY. 1s 
A third parasite (Polygnotus hiemalis 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-fly, 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- 
_ Fig. 6.—Pupa- ed as they make a perfectly circular hole 
rium of Hessian-fY through the straw to reach the outside of 
with six cocoons of 
ite. En- : . 
fecasonens. ptielrapiison,; such holes are as large asa 
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. Atware 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 way as to prevent the entrance 
of moisture. 
; If this dangerous insect is single- 
brooded in Minnesota, a point now al- 
most definitely settled, a remedy is very 
simple, and, in most years, can be ap- Ar het Chat ee gaeane ee 
plied without any extra expense or lab- Pere teee neimauner ta 
or, The insects. hibernating in straws freak. eer rae 
usually just over the first joint, remain 7k 
in the stubble until early spring, when they hatch and de- 


