PROTECTION 167 
every animal which lived and nested upon the ground 
was killed. Snakes, lizards, birds, ete., were either 
exterminated or reduced in numbers by this noxious 
animal. Insects increased enormously in consequence 
of the destruction of their enemies. The mongoos 
invaded even the hennery. 
A professor in Harvard University accidentally 
let loose a few specimens of the European gipsy-moth 
near Boston. It increased enormously so that the 
State of Massachusetts has already expended an im- 
mense sum of money in combating it. 
In the forest there are usually three grades of 
insects—the noxious, the neutral, and the beneficial 
kinds. 
Some trees are rarely if ever affected by insect 
pests; the tulip-poplar, the black walnut, and liquid- 
ambar, for instance. Others are constantly infested 
with one or more kinds. It is difficult to find a locust- 
tree of considerable size which has not been more or 
less damaged by the borer (Cyllene robinie). 
There are wood-boring and timber-destroying in- 
sects; there are defoliators, root, bud, and seed de- 
stroyers, and there is an abundance of species such 
as mosquitoes, punkies, and flies, which render work 
in the forest at times extremely uncomfortable. The 
healthfulness of a country may depend upon the pres- 
ence of mosquitoes, since both malaria and yellow 
