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merit that the locusts could be effectually destroyed by the use of the 
bran and arsenic mixture when they occurred in ordinary numbers, 1 »u t 
1 was informed that where they came in large swarms this mixture 
scarcely produced any appreciable effect in lessening their numbers, 
dozens of individuals coining to take the place of each of their fallen 
comrades, and these new comers succeeded in almost completely defoli- 
ating the trees in spite of the presence of the poisonous mixture. Un- 
fortunately, 1 had no opportunity of testing this matter myself and 
therefore am unable to decide in regard to the truthfulness of this state- 
ment from personal experience. 
Much might be accomplished in the matter of preventing the appear- 
ance in the cultivated orchards of the migrating swarms by destroying 
either the eggs or the young locusts in their natural breeding grounds. 
In a previous chapter I have given my reasons for believing that the 
swarms of locusts that occasionally appear in portions of the San Joa- 
quin and Sacramento Valleys hatch out in the pasture lands among the 
foothills along the western base of the Sierra Nevada Mountains, in 
land overgrown with tarweeds. The eggs in these breeding grounds 
might be destroyed either by burning over these grounds late in the 
autumn after all of the eggs are laid, or by plowing under the eggs to 
a depth of G or 8 inches at any time before they hatch out in the spring. 
The eggs of the migrating California locust have never been seen by 
me, but there is every reason for believing that they are deposited in 
the same manner as those of other species belonging to the same genus. 
These are deposited in a mass, the upper part of which is nearly on a 
level with the surface of the ground, while the lower part is within three- 
quarters of an inch of the surface. It is very probable, therefore, that 
where there is any considerable quantity of dry weeds and other litter 
scattered over the breeding ground, by setting fire to this litter the 
heat generated from it would be sufficient to destroy all of the eggs 
existing in the ground thus burned over. 
Instead of thus destroying the eggs it might be advisable to wait 
until the young locusts have hatched out in the following spring, and 
then destroy these young ones before they have acquired wings and 
migrated from the breeding grounds. This could evidently be accom- 
plished with the least trouble and expense by scattering the bran and 
arsenic mixture over the breeding grounds shortly after the young 
locusts first make their appearance. In case that these breeding 
grounds occur in pasture lands it might be advisable to fence them in, 
so as to prevent the stock from being poisoned by this mixture put out 
for the locusts. I am not aware that stock of any kind will feed upon 
the tarweeds, so that but little loss in pasturage would be experienced 
if the stock were to be prevented from ranging over patches o\' them. 
I have been credibly informed that this method of poisoning the young 
locusts in their natural breeding grounds has been practiced in Fresno 
County for several years past, and that since it was tirst adopted no 
serious outbreaks of locusts have occurred in that county. 
