40 INSECTS AFFECTING STORED PRODUCTS. 
For the first experiment about 100 pockets of screenings, rough 
and clean rice bran, brewer's grain, and the various materials about 
the mill were put in the room; some upon the trestle, others on the 
floor in loose and compact stacks, to represent the different condi- 
tions found in the mill and warehouse. 
The most abundant species was Rhizopertha dominica, as stated 
above, but an effort w T as made to have all other species around the 
premises represented in larval and adult stages at least, and these 
were placed at various depths in the sacks and in piles of materials 
contained in them. 
When a visit was made to this mill early in December, 1909, the 
manager became interested in the idea of having a special room or 
chamber constructed in the mill or warehouse in which to place in- 
fested material for treatment. He agreed to have such a room built 
according to directions given by the writer. Efforts were made at 
several other rice mills to have a practical gas-proof chamber built 
by the owners as a permanent adjunct to their plants, but without 
success. 
Later one of these firms constructed a room for fumigating and 
used it for treating clean rice with sulphur fumes. It was built in 
the corner of the clean-rice warehouse by erecting two partitions of 
tongue-and-groove flooring, single thickness, and had become cracked 
and warped in some places. 
It required considerable work and time to line and make it gas 
tight. When another visit was made to this mill carpenters had built 
a fumigating chamber in the rough-rice warehouse for convenience 
in treating screenings from the rough rice and also the brewer's grain 
and other infested material which was stored in the rough-rice build- 
ing. The next experiments (Nos. 14-17) were made by Mr. M. M. 
High. 
Experiments by M. M. High. 
HYDROCYANIC-ACID GAS FROM SODIUM CYANID. 
Experiment No. 14- — December 16, 1910, the fumigating room just 
described was carefully inspected for outlets for the escape of the gas. 
Two holes about the size of one's finger, which had evidently been 
made by the careless use of trucks, in one wall and a rat hole in one 
corner of the room were covered and 120 sacks of infested rough rice 
were placed in the room, care being taken to stack closely. In this 
the most numerous insect pest was the lesser grain-borer (Rhizopertha 
dominica). Four other species were present in smaller numbers." 
° Of these the rust-red flour beetle (TriboHum navale Fab.) was second in 
abundance, followed by the rice weevil (Calandra oryza L.), the cadelle 
(Tenebroides maurltanicus L.), a few individuals of the saw-toothed grain 
beetle (Silvanus surinamensis L.), and the fig moth (Epliestia cautella Walk.). 
