181 
specimens were scattered, while the remainder of the field was to be 
plowed for wheat within a few days. The fact that specimens of the 
Semiotellus continued to emerge from the check lot retained at Cham- 
paign for some weeks after this distribution is evidence that a consid- 
erable nuniber of the parasites must have gone abroad in Scott County. 
Indeed, forty or fifty of them, which had completed their transformations 
en route, escaped from the box when it was opened in the field. 
It will be seen from the foregoing narrative that we succeeded com- 
pletely in breeding a generation of the foreign parasite in our plots of 
wheat infested by the Hessian Fly, and that these bred insects were suc- — 
cessfully distributed to fields infested by the fly at two places in IIli- 
nois—in Champaign and Scott counties, respectively. 
It should be said in conclusion that the latter part of the summer was 
exceedingly dry throughout central Illinois, and that as a consequence 
but little volunteer grain grew in either of the above localities, and that 
neither in this nor in the early sown wheat was there any considera- 
ble amount of Hessian Fly attack—circumstances which are to some 
extent unfavorable to rapid success of the experiment for the introduc- 
tion of this parasite. The Vantyle farm was visited by my assistant, 
Mr. Marten, September 24, at which time the plowed portion of the field 
was being drilled to wheat. Along the margins of this plowed ground, 
near the plot which had been left in stubble, was a scanty growth of 
volunteer wheat in which, after considerable search, four nearly full 
grown larve of the Hessian Fly and one fresh puparium were found. 
Little other volunteer wheat was seen in the neighborhood. <A brief | 
search of the stubble remaining showed only parasitized puparia from 
which parasites had already escaped. 
The Champaign County plot was examined September 30, when one 
hundred and twenty plants of volunteer wheat grown in the experi- 
mental stubble field were overhauled. In these plants two larve and 
seven puparia of the Hessian Fly were found. October 5 from forty- 
three plants eight puparia and two nearly full-grown larve were taken. 
As the period of the emergence of the imported Semiotellus was sub- 
stantially the same as that of the native S. destructor, the two coming 
out side by side in our breeding cages, it seems practically certain that 
the imported parasite must have had as fair a chance for propagation 
in the field as its native congener. 
We will of course keep careful watch of these localities next year, 
and will notify you of any observations then made bearing on the reap- 
pearance and the spread of this imported enemy of the Hessian Fly. 
To C. V. RILEY, 
U. S. Entomologist. 
