56 INSECTS AFFECTING STORED PEODUCTS. 
the temperature had increased from 76° to 90° F. An examina- 
tion of the corn showed extensive damage by the granary weevil 
( Calandra granaria L.), while Cdenocorse ratzeburgi Wissm. and Laemo- 
phlceus minutus Oliv. were also present in some numbers. Since 
the bin was of concrete and capable of being tightly closed, the oppor- 
tunity was taken by the junior author for a thorough trial of carbon 
tetrachlorid as a f umigant. The bin was a trifle over 6 feet square 
and 75 feet in depth, giving a capacity of approximately 3,000 cubic 
feet. A dose of 15 pounds of tetrachlorid was poured over the grain 
from the top of the bin, the grain, 1,300 bushels in all, extending 
nearly to the top of the bin. The bin was closed and left for four 
days. October 29, when opened, a slight odor of gas remained. The 
grain was run over a No. 8 screen and the estimate of mortality made 
from the insects found. No living Ceenocorse or Silvan us were 
observed. About 50 to 60 per cent of the Calandras were killed, the 
remainder being very stupid after the screening and thorough airing. 
The weevils in this case were left in separate jars for a number of 
days afterwards in order to ascertain if recovery took place later, but 
no difference in the number killed was noted. 
Experiment No. 6. — A second fumigation was applied early in 
"November, the fumigant being used in the same bin, but at the rate 
of 9 pounds to 1,000 cubic feet. At this rate the poison was applied 
in five layers, 250 bushels of corn being run into the bin between 
applications of 5 pounds each of carbon tetrachlorid. The bin was 
closed 5 days, then the corn was run over a No. 6 screen, and speci- 
mens of weevils collected from the screenings. In this treatment 
about 90 per cent of the weevils, which by this time consisted almost 
entirely of Calandra granaria, were killed. 
Specimens were exposed for recovery but failed to do so. The odor 
of carbon tetrachlorid was strongly noticeable while the corn was 
being screened and the gas was apparently well distributed through 
the corn. This experiment would indicate that carbon tetrachlorid 
is much less valuable as an insecticide than the bisulphid. The 
tetrachlorid used was purchased in the open market in Baltimore, at a 
cost of 28 cents a pound. 
COMPARATIVE COST OP CARBON TETRACHLORID AND CARBON 
BISULPHID. 
Inquiry of the Bureau of Chemistry in regard to the comparative 
cost of these chemicals elicited the reply that the contract prices for 
supplies for the Department of Agriculture for the year ending June 
30, 1909, quoted carbon bisulphid at $0.11 a pound (quality not desig- 
nated) to $0.28 a pound (chemically pure), while carbon tetrachlorid 
was quoted from $0.45 to $1 a pound. Prices in the Oil, Paint and 
