48 
It was found to do very good service, killing the young locusts in 
considerable numbers. The oil did not evaporate so rapidly as was 
anticipated. One thorough saturation was sufficient for fifteen or 
twenty minutes, when a little more could be added. If the machine 
be hauled against the wind, nearly all the locusts which hop will touch 
the oiled canvas. They generally take several hops upon the canvas 
before leaving it, thus insuring a thorough saturation with the oil. After 
hopping from the apron they can take two or three hops upon the 
ground, then lose all power in their hind legs, stretching them straight 
out behind, and finally, in one or two minutes after being " oiled," they 
are dead. 
Coal Tar. — This may be used with most of the contrivances just de- 
scribed for the use of kerosene, and while not equal to the simple kero- 
sene pan for speed in trapping and destroying, is yet very useful, espe- 
cially in the neighborhood of gasworks where the coal tar can be obtained 
at nominal cost. It also permits the use of the simplest kind of pan. 
Enough tar is spread over whatever receptacle may be used to cover 
well the bottom, and when this becomes sufficiently matted with the 
young locusts so as no longer to destroy the new comers, another coat- 
ing is added, and so on until it becomes necessary to remove the whole 
mass, when it is shoveled from the pan and burned; or, what is far 
preferable, wherever there are wet ditches it may be thrown into these, 
when the oil contained in it, spreading over the surface of the water, 
destroys such locusts as may jump into or be driven into such ditches. 
Where the tar is scarce, as a matter of economy it will pay to melt the 
accumulated mass in iron vessels. By skimming off the dead locusts 
that rise to the surface, and thinning the residuum with a little coal oil, 
it may be used again. 
A simple pan extensively employed, and which was known as the 
Bobbins "hopperdozer,"* is shown in the accompanying illustration (PI. 
ix, Big. 1), the general plan being that of the ordinary road scraper. Its 
simplicity and durability account for its general use. It was usually 
drawn by hand, though several pans were frequently bound together 
and drawn by horses; while, in some instances, certain improvements 
in the way of mounting on wheels, so as to permit its being pushed from 
behind, were also adopted. We saw some with a wire screen or cover 
hinged to the back, so that the insects might be secured when the pan 
was not in motion ; but the cover seemed superfluous. We also saw 
lime and kerosene mixed so as to form a mortar substituted for the 
coal tar. 
Another device was used in Colorado last summer, but is more com- 
plicated. It consisted of a skeleton cylinder of wood framework cov- 
ered with canvas, the interior of which was to be coated with coal tar. 
The ends were opened and fans were arranged there, so constructed as 
* A word that came into very general nse last year among farmers for coal-oil and 
coal-tar machines, and which doubtless takes its origin from doze, in reference to the 
toxic effect of the coal-tar on the locusts. 
