TIMBER; FORESTRY 123 
6. Wood-boring and leaf-eating insects should be killed, 
if the expense of the process is not too great. It is suggested, 
for example, that the great damage caused by the spruce- 
destroying beetle, which kills mature trees by mining the bark 
of the trunk, may be much lessened. This can be accomplished 
by cutting and removing most of the infested trees or by gir- 
dling trees early in June, to expose them to the attacks of the 
beetles, then felling and either peeling 
them or immersing them in water, to 
destroy the insects before the new crop 
of beetles emerges from under the bark 
the following June. 
One of the most effectual means of 
destroying some injurious insects con- 
sists In introducing into the region where 
they abound parasitic or other insects 
which will kill great numbers of the 
objectionable species. Plant lice, for in- 
Fig. 100. .A carnivorous 
beetle (Calosoma syco- 
phanta) which destroys 
the caterpillars of the 
stance, are thus killed by ladybugs. 
Vigorous attempts are now being made 
to exterminate the gvpsy moth in New 
England by means of parasites and by 
carnivorous insects (fig. 100) which at- 
tack and kill the moth at some stage of 
gypsy moth 
These beetles have been 
imported from Europe, 
and successful colonies of 
them established in New 
England. After United 
States Department of 
Agriculture 
its existence. The caterpillars of this 
moth are extremely destructive to many kinds of trees, which 
they strip of their leaves in a short time. More than a million 
dollars has probably been expended in Massachusetts alone in 
trying to get rid of this pest. The moth was introduced into 
America in 1869, by a scientist who lived at Medford, near 
Boston, in the course of some most unfortunate experiments 
on silk-producing insects.? 
1 See “Insect Enemies of the Spruce in the Northeast,” Bulletin 28, 
New Series, Division of Entomology, U.S. Dept. Agr., 1901. 
2" The Gypsy Moth in America,’ Bulletin 11, New Series, Division of 
Entomology, U.S. Dept. Agr., 1897. 
