and the doors and ventilators were kept open for several days, so as 
to allow it to become as warm as possible, in order to render the 
larvee more active. 
The maximum temperature from April 25 to May 12, the date 
when the house was fumigated, was 84° and the minimum 33° F. 
May 11, the night before the treatment was applied, the thermometer 
dropped to 33°, but rose rapidly the following day, registering 
80° F. in the afternoon. 
Before charging the house, my assistant, Mr. Swezey, who was sent 
to do the work, examined many cocoons, and active larve, but no 
pup, were found. 
The formula used was 1 ounce of potassium cyanide 98 per cent 
pure, 1 fluid ounce of sulphuric acid, and 3 fluid ounces of water to 
each 100 cubic feet of space. As the house measured 32 by 24 by 14 
feet, 62 pounds of cyanide were required: this was divided into 
three equal parts and placed in separate jars. The ventilators were 
tightly closed and the house charged at 3 p. m., and the door was 
opened at the expiration of twenty hours. The odor of gas was then 
very strong, and, after airing for one hour, Mr. Swezey made an ex- 
amination of cocoons taken from several boxes. Sixty-nine worms 
were removed and placed in a jar, and as about one-third of these 
showed signs of life when they were taken the house was closed and 
allowed to remain so for over a week. 
An examination of the worms in the jar, which was made five hours 
after they were taken, showed that 39 were alive and 30 were appar- 
ently dead. A final examination made June 9 gave the following 
data: 28 worms and 3 pup dead, and 1 larva, 6 pupe, and 23 moths 
alive. Eight jarve had escaped from the jar. 
Taking this count as a basis, 1t is evident that the gas Inlled less 
than 45 per cent of the worms. In removing the larve from the 
boxes, 1t was almost impossible to prevent injuring the cocoons, and 
in many cases the larve placed in the jar left the old cocoons and spun 
entirely new ones. This would undoubtedly have some influence on 
the death rate,-and under normal conditions, where the cocoons were 
undisturbed, the treatment would not be as effective as in this instance. 
An examination of cocoons in the iruit house May 26 showed that 
less than 40 per cent of the larvee were dead, although the house had 
been tightly closed since the day it was first aired out, and the odor of 
the gas was still very perceptible. Computing the price of the cyanide 
at 30 cents and the acid at 5 cents per pound, the cost of this treatment_ 
was $2.36. Had it been effective in destroying the larve it would 
have furnished a simple and comparatively cheap method of treating 
fruit houses and would have been preferable to the use of screens on 
the doors and ventilators, which are lable through carelessness or 
accident to be Jeft open and give the moths an opportunity to escape. i 
