416 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
within a small silken web, where it molts. The second instar feeds 
for 5 or 6 days, migrates to a branch or trunk of the tree, constructs 
its hibernaculum and then molts before retiring for the winter. Oc- 
casionally a few larvae continue their activity until late fall. The 
larvae emerge from hibernation during the latter part of April or 
early in May and usually attain full growth in June. Beginning with 
the fourth instar the larvae devour the entire leaf substance instead 
of skeletonizing it. Both sexes pass through seven larval instars be- | 
fore pupation, and about 9 or 10 days are spent in the pupal stage. 
Economic Fratures.—Since its discovery in Massachusetts in 1920 
the satin moth has caused serious defoliation in many parts of New 
England. The shade and ornamental poplars and willows are most 
severely attacked, although one serious infestation has been observed 
in a natural stand of large-tooth aspen. Municipalities and private 
property owners have spent large sums in spraying to prevent defolia- 
tion. In severe infestations larvae often migrate from defoliated 
trees to fences, walks, and buildings causing serious annoyance to 
nearby dwellers. 
NaturaL Enemies.—F our foreign species, Compsilura concinnata, 
Sturmia scutellata, Eupteromalus nidulans (Thom.), and Calosoma 
sycophanta, introduced as natural enemies of other forest pests, and 
several native insects attack the satin moth. Of these C. concinnata 
and #. nidulans are most important as control agents. Several Euro- 
pean parasites of the satin moth have been imported, but thus far in 
the New England infested area only Apanteles solitarius Ratz. has 
become of importance as a control factor. In the Washington and 
Oregon infested area, in addition to the important parasites noted 
above, an introduced parasite, Meteorus versicolor, has become estab- 
lished and is now a very effective parasite. A native tachinid, 
Tachinomyia similis (Will.), is also of considerable importance as a 
parasite of the satin moth in Oregon and Washington. Jones, Webber, 
and Dowden (260) published on the enemies of this insect. 
) 
Famity LASIOCAMPIDAE 
The family Lasiocampidae has less than 30 species in North Amer- 
ica, and the tent caterpillars are its best known representatives. The 
moths are of medium size and have stout hairy bodies. The larvae of 
all species are very hairy, but vary in form from nearly cylindrical to 
very much flattened. Two species are important pests in the eastern 
part of the United States. 
The moth of the eastern tent caterpillar (J/alacosoma americana , 
(F.)) has a wing expanse ranging from 114 to 2 inches. It is stout 
bodied and dull reddish brown, with two whitish stripes extending 
obliquely across the forewings (fig. 85, A, a). The eggs are depositec 
in masses of from 150 to 350, each mass encircling a twig (fig. 85, A, 0). 
They are cemented together and coated with a dark gluelike substance 
which hardens and forms an oval-shaped dark-brown mass, with a 
varnished appearance. The caterpillar (fig. 85, A,d@) when full grown 
is about 2 to 21% inches long, and cylindrical. The head and body are 
deep black with a white stripe along the back, and with many short, 
irregular, brownish markings along the side of each segment. Also 
on each side is a row of oval, pale-blue spots nearly surrounded by | 
black. The body is sparsely clothed with long, fine, hght-brown hairs. 
oe 
