92 
Observations on the various Insects 
3rdly. The moths themselves might be destroyed in April and 
May, when they deposit their eggs, by burning a very powerful 
light, even in the daytime in dark granaries; for being attracted 
by the brightness of the flame, they would fly into it and be de- 
stroyed, or fall down sufficiently injured to prevent their doing 
any further mischief,* and at the same time the corn ought to be 
frequently turned over with shovels, to kill the eggs and disturb 
(he young larvae. 
To complete the work, all cracks and broken places in the 
walls and roof must be stopped with Roman cement or plaster of 
Paris, to prevent the ingress of the moth, and the apertures left 
for light or ventilation must be covered with wire gauze. It is a 
great mistake to leave the inside walls and roof in a rough state, 
as they afford exactly the retreats fit for the transformations of the 
larvae : it would therefore be very advisable to have them smoothly 
plastered. 
When the larvae are securely feeding in the grain, one of the 
best remedies is to subject the whole to a sufficient degree of 
heat to destroy the insects. This is said to be best effected by 
kiln-drying, as a temperature of 19 of Reaumur (about 78° 
Fahr.) will kill the larvae ; but it can only be applied to corn in- 
tended for the mill, as it destroys the vital principle so that it will 
not germinate.f The great object in this process is to obtain the 
required heat as speedily as possible, and to let the vapour escape 
through apertures made for the purpose, in order that no unplea- 
sant odour may be communicated to the corn. 
Having so far shown what may be accomplished by heat, I wish 
now to turn the reader's attention to what has been proposed to 
be effected by an opposite process, which may be termed the 
Cooling system. It being ascertained that the larvae of the corn- 
moth cannot live in a lower temperature than 12° or 10° of Reau- 
mur — namely, under a temperate heat — that they become torpid 
in a temperature of 6° or only 8^ above zero, and that they die if 
this low state be maintained lor any length of time, Dr. Hammer- 
schmidtj has proved by repeated experiments, that by keeping up 
* A contributor to the Gardener's Chronicle says, " Would not a few 
gas-lights kept burning in the granaries, during the months the perfect 
insect is on the wing, prove both attractive and destructive of this pest ? 
Lamps would not do, as they would soon be extinguished by the dead 
moths." — vol. i. p. 133. 
t Such is Kollars statement in his Natur der Schoed. Insecten, p. 128, 
but surely it must be incorrect, as the French assert that GO degrees of 
lleaumur will not injure the germination of the corn, and it is liable to a 
much higher temperature than 10 degrees in the open field. 
X Kollar, p 128. I may here acknowledge my obligations to this useful 
work, and the translation, for many of the foregoing observations relative 
to the lYnea granella. 
