THE BAG-WORM. 27 
it is occasionally found in New York, and even Massachusetts, but so 
rarely and locally restricted that neither Dr. Harris nor Dr. Fitch men- 
tion it in their publications on economic entomology. Wherever it oc- 
curs it prefers the gardens and parks within or near the cities, being 
much less abundant in the woods remote from cities, and this depend- 
ence upon the vicinity of human civilization is more marked in this 
species than in any of the others here treated of. 
FOOD PLANTS. 
The Bag-worm is known to feed on a large number of trees and shrubs, 
but has a predilection for certain kinds of coniferous trees, notably the 
Red Cedar and Arbor Vite, and as these evergreens are much less able 
to stand the loss of their foliage than the deciduous trees, the worms 
are much more dan gerous to the former than to the latter. The Hard 
Maples are, as a rule, avoided by the worms, and it is also quite notice- 
able that they are not particularly fond of oak leaves and those of the 
Paulonias. The Ailanthus trees are also generally exempt from their 
attacks, either on account of the unpleasant taste of the leaves, or per- 
haps on account of the compound nature of the leaves, the worms fast- 
ening their bags to the leaf stems which fall to the ground in Fall. 
With these exceptions,* the worms, when sufficiently numerous, do 
_great damage to most other kinds of trees used in our cities-as shade 
and park trees. 
ENEMIES. 
The Bag-worm is so well protected in all its stages that no insectiv- 
orous bird nor predaceous insect is known to attack it. In spite of 
Fic. 11.—Pimpla conquisitor: a, larva; b, head of do. from front; c, 
pupa; d, adult female (hair line indicating natural size); e, end of male 
abdomen from above; f, same from the side—all enlarged. 
the absence of predaceous enemies, the Bag-worm suffers from the 
attacks of at least six true parasites, while two others, which may be 
* The China trees of our Southern cities are entirely exempt from the worms, 
