12 THE HESSIAN-FLY, 
ern states this insect is double brooded, and hibernates in 
the flax-seed stage in winter-wheat, volunteer-wheat and in 
other plants including, possibly, some of the larger grasses. 
But this is their habit only in the south: here the insect 
must lead a different sort of life, for instead of being double- 
brooded it is single-brooded. This could be expected from the 
conditions prevailing in the greater portion of our state, 
but we have had no proofs thus far. Of all the infested 
stalks gathered as soon 
as the injury became 
visible, not a_ single 
Hessian-fly has issued, 
and namerous puparia 
(the flax-seed stage) 
are still unchanged in 
the breeding-cages. 
This assuredly seems to 
indicate that the flies 
Fig. 4—Female of Merisus destructor Say. do not issue during the 
BLE ee aed autumn, as they do fur- 
ther south, but remain in the culm until spring. Another 
proof, though not a safe one to depend upon, is the fact that 
no larve or puparia could be found in the volunteer plants 
of wheat growing near fields that had been hadly infested. 
The many puparia kept in properly constructed breeding- 
cages gave forth, however, : 
very large numbers of para- 
sites. Three different species 
were raised, and in such 
numbers that in some cases 
nearly all the Hessian-flies 
had been destroyed in the 
puparia. Two of the para- 
sites are shown in the illus- 
tration. Fig. 4 represents a 
female of the most common Fig. spelt. of ible allynii 
parasite (JMerisus destructor French. Enlarged. Original. 
Say) and fig. 5 the male of (Hupelmus allynu French). The 
female of the latter occurs both with and without wings. 


