39 Farmers’ Bulletin 1169. 
winter in the bag and late the following spring hatch into cater- 
pillars, which make their way to the nearest leaf and immediately 
begin to feed and construct bags for themselves. The bags are made 
from bits of the foliage on which they feed and silk spun by them. 
In the latitude of Washington, D. C., it takes the bagworm a full 
year to complete its life cycle. 
Control.—Several forms of parasitic insects prey on the bagworm, 
keeping its numbers within harmless bounds during most years. 
From time to time, however, this check fails to operate, and then 
artificial measures of control must be resorted to. 
I1c. 17.—Twig of conifer completely defoliated by bagworms, showing bags in various 
stages of development. (Photo by Paine.) 
It is clear from the seasonal history of the insect that if, wherever 
practicable, the bags be picked off the trees during the winter and 
burned, so many eggs will have been destroyed that the damage the 
following season will be limited to the caterpillars from the eggs 
in the few overlooked bags. A better practice than burning the 
bags, however, would be to confine them in a bag made of sheer or 
coarse material and suspended from the ceiling of an outhouse, thus 
allowing the issue and escape of parasites they may contain, confin- 
ing the bagworms until they die, and protecting the mass from de- 
struction by mice, decay, etc. Where hand picking is impracticable, 
and especially on evergreen trees, the most efficient remedy is to spray 
