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THE LESSER GRAIN-BORER. 41 
Sixty-five sacks of chicken feed, in which this grain-borer was de- 
cidedly the most numerous pest, were also placed in the fumigating 
room. Everything needed to charge the room with hydrocyanic-acid 
gas was put in place, and at 5.20 p. m. fumigation was begun. The 
cubic capacity of the room was approximately 2,600 feet. The rate 
of application was 20 ounces to 1,000 cubic feet of space, using the 
1-1-8 formula, 1. e., 1 ounce sodium cyanid, 1 fluid ounce sulphuric 
acid (commercial), and 3 fluid ounces water. After the bags of 
eyanid had been placed in the jars the door was closed immediately, 
taking care to make it as tight as possible. The door remained closed 
until 5.20 p. m. on December 17, thus making a period of 24 hours’ 
exposure. After the door had been opened a short time the room was 
entered to ascertain results. The fumigating room had only one 
door and no windows, so_an electric globe was used. Samples were 
taken from sacks in different parts of the room, from the middle of 
the stack, and from the sacks on the floor. Nearly every one was ex- 
amined with a trowel, so as to reach the middle of the sack. .Dead 
bodies of Rhizopertha almost completely covered the sacks of the 
chicken-feed rice and were nearly as abundant over the sacks of the 
rough rice. Beetles of this species were dead all over the room, with 
the exception of a few individuals taken from the middle of a sack 
that lay at the base of one of the jars used. On the interior of this 
sack, which was probed deeply a number of times, a few beetles were 
struggling between life and death, while the outside of the sack was 
covered with their dead bodies.* 
Experiment No, 15.—As Silvanus and Tribolium appeared more 
abundant in the clean rice, the manager of the mill was asked for 
150 pockets of clean rice to be placed in the fumigating room; but 
as the mill where the clean rice was stored and the fumigating room 
were some distance apart, a wagon had to be used. This was rather 
slow with a limited number of men, so that only 25 pockets of the 
clean rice were transported to the fumigating room: This, however, 
was placed with the rough rice, so as to make results the same as they 
would have been had a greater amount of clean rice been secured. 
On December 19 at 3 p. m. the charge was liberated. The amount of 
cyanid was the same as used in the previous charge, 1. e., 20 ounces 
to 1,000 cubic feet of space, but the room was to remain closed 48 
hours instead of 24. 
December 21, at the same hour, the fumigating room was opened 
and an examination begun. Out of the first lot of samples taken, 
which were from pockets near and upon the floor, a few individuals 
4Tribolium navale, which was not nearly so numerous in the rough rice as 
the Rhizopertha, was yet quite active. No live specimens of Calandra or 
Tenebroides were found. 
