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ENTOMOLOGY. 95 
he advent of the evil by proper foreknowledge, and prophylactic 
steps; 2d, Cure, i. e., the destruction of the pests, in one way or 
another, when once they are upon us. This last method consists 
of two distinct plans of action—that of killing directly by hand- 
picking, machinery, or the application of destructive substances to 
the plants or animals affected; and that of causing them to be 
killed by encouraging their natural enemies. 
PREVENTION.—The first method—prevention—is by far the most 
satisfactory. 
The feathery snow-flake, on its zerial course, 
Is made, with ease, to vanish by a breath ; 
To avalanche augmented, ’tis the source 
OF dire calamity—inevitable death ! 
It is a notorious fact that many of the most troublesome weeds of 
American agriculture as also some of its very worst insect enemies 
have been imported among us from Europe; and in the Second 
Missouri Entomological Report will be found a partial list, which 
might be greatly extended, of such imported species. The single 
case of the Rape Butterfly (Pre7ts rape) will serve to show how rap- 
idly these foreigners multiply, and how injurious they become when 
unattended by the natural enemies which keep them in check in their 
native homes. Introduced at Quebec, Canada, in 1856, it has now 
spread over Canada West and most of the New England States, as 
far South as Baltimore and nearing the eastern limit of New York. 
It sweeps the cabbage crop at all points it reaches and caused, in 
1871, a loss of $500,000 in the vicinity of New York City alone, 
if we are to believe the New York Z7idune. 
Now, there cannot be the least doubt but that with the proper 
precautionary steps many of these immigrants from a foreign land’ 
need never have been introduced, or might have been stamped out, 
on first arrival, and kept from spreading over our fair country. 
But insects not only spread from one country to another, they 
spread from State to State, from county to county and from 
Ps bg pe J 
orchard to orchard, and in very many inst p I 
toplace is very easily prevented, but unfortunately, just as easily, and 
more often, aided by man. Quite a number of our most noxious 
species would scarcely spread fifty miles in a century, were it not 
for the aid which man in his carelessness gives them. Some are 
active but a single day in the year; some move slowly under 
ground ; some never quit the trees on which they are born, while 
still others are apterous in the female sex, and have otherwise very 
feeble ambulatory power. 
In checking the spread of noxious insects does not consist the 
only way to prevent their injuries. We can also take advantage of 
their weak points, or nip the evil in the bud. Thus, when we 
know that the parent Hessian-fly (Cectdomyia destructor) makes its 
first appearance in this latitule the fore part of September and 
usually leaves by the end of the same month, we may avoid its inju- 
ries by deferring the planting of our grain till into October. And 
if the parent Army-worm (Lucania unipuncta) deposits her eggs at 
at the base of grass stalks in the fall of the year, we may avoid 
the ravages of her progeny by burning the stubble in the winter. 
A great many species which, like the Army-worm, are difficult to 
control in their other stages,. are thus readily killed in the egg stage. 
Cure.—The second method, namely, the cure of the evil when 
onceit is upon us, is sometimes sufficiently easy ; at others almost, or 
quite, impossible. As, already stated, we have here two distinct lines 
of action. That of killing the pests requires our ingenuity in the 
construction of mechanical devices, or our time and patience in the 
test and repeated trial of some external application that will kill 
the enemy while it leaves the plant, or the animal, uninjured. 
Here we learn the value of such contrivances as Dr. Huty’s Curcu- 
lio-catcher [Fig. 1] and the many modifications of it that have 
been used: here we see the importance of such applications as lime 
for slug-worms (genus Se/andria) and other larve having soft, 
slimy skins; of white hellebore for the currant-worms (genus 
(Mematus), and of some preparation having Paris Green as its base, 
for the notorious Potato Beetle (Doryphora 10-lineata). Asarule, 
however, these methods of cure are far less satisfactory in their 
results than the modes of prevention, and should never be relied 
on when the latter can be resorted to. 
That of causing them to be killed by encouraging their natural ene- 
mies, is one of the most effectual methods of counterworking noxious 
insects. Among such natural enemies, birds, toads, snakes and other 
reptiles hold a prominent place; and we have here to treat of the 
complicated bird question, or what may be termed ornithological 
entomology, which is yet in its infancy and calls loudly for more 
attention. But the more important enemies of noxious insects are 
