THE BROAD-BEAN WEEVIL. 
79 
to his own satisfaction. Perfectly air-tight inclosures are difficult to 
obtain unless specially constructed with this particular end in view. 
A fumigator of the type described is illustrated by figure 20. It has 
a capacity of 100 cubic feet and is supplied with a pair of tight-closing 
handles, which are a necessity to prevent warping. Of three fumiga- 
Fig. 20.— Fumigator used for stored products infested by insects. (Original.) 
tors of similar pattern one was constructed with a single handle, which 
was not according to specification, and warped badly in consequence. 
It should be added that in order to destroy insects in a fumigator or 
other inclosure at a temperature much below 50° F. a larger quantity 
of the bisulphid of carbon is necessary than when the temperature is 
about 80° to 90° F. 
