150 Ss 
than twenty adults could be counted in the eage ata time, not to men- — 
tion others doubtless concealed in the wheat. 
The first lot of foreign parasites was exposed in this cage May 7, and- 
the second lot May 11, both packages containing living adults when 
opened. 
At the time of the first introduction eighteen of the wheat stalks were 
_ examined, and fifteen young larve of the Hessian fly were found upon 
them, and all the conditions were thus favorable to the success of the 
experiment. Four days after the introduction of the parasitized foreign 
_ Material five freshly emerged specimens of Semiotellus nigripes were 
noticed in has cage, and others appeared May 15, June 29 and 30, and 
July 1,5, 9, and 14. On the date last mentioned the wheat in the cage | 
was ova lanled: and the puparia were removed and divided into three 
lots; one to be Kept at the office for regular observation of the trans- 
formations; one to be taken into southern Dlinois and distributed 
through fields of stubble containing Hessian Fly puparia, and a third to 
be sent. in accordance with your letter of July 7. to Mr. James Fletcher, 
Dominion Entomologist, Ottawa, Canada. 
The parasitized puparia received from Washington were all spent ie 
this time. or perhaps some time before. Removed from the cage July 
18, they were Kept until October 7 without the appearance of another 
parasitic insect. Parasites of the new generation continued to emerge 
from the lot kept for observation until August 29, the exact dates being 
July 16, 18, 21, 23, 24, 27, 31, and August 1, 6, 10, 12, 16, 20, 25,25, 
and 29 
Most of these were released in a field of moderately infested wheat 
stubble on the experimental farm of the Agricultural Experiment Sia- 
tion at Champaign. Desunins with 4 specimens July 22, and adding 15 
a 1, 18 August 6, 23 August 10, 15 August 12, and 4 August 20— 
77 adults in all beng thas released at this place. 
In the meantime measures had been taken to introduce the parasites 
on a larger scale in southern Illinois. Taking with me about two-thirds 
of the material obtained from our breeding-cage experiment—the para- 
sitized puparia still in the straws—lI traversed several counties from 
Centralia south to Union County, and thence to St. Louis and Jackson- 
ville, stopping at intervals, but finding no satisfactory situation until I 
reached Scott County, July 17. On the farm of Messrs. Edward and 
Frederick Vantyle a field was found three miles northeast of Roodhouse 
the yield of which had been reduced by the Hessian Fly from about 30 to 
39 bushels to the acre to 15. It was the only field in the immediate — 
neighborhood which had been so damaged, and in this one the fly had 
not been noticed the year before. There was consequently little proba- 
bility of excessive native parasitism of the succeeding brood, and it 
seemed likely that the fly would occur there this —— in volunteer grain 
and later in the regular sowing. 
The owners agreed to leave unplowed a piece of stubble on which my a 
