5 
the circle is complete. Then row after row of fragments is added 
until the case becomes a hollow cylinder (fig. 4, ¢). One end is then 
closed up and the inside lined with a tough coating of silk, the case 
being then extended upright and fastenedat one end. When it is fully 
completed the larva crawls away, with the case carried upright like 
a cap on the upturned end of its body. In the illustration d shows a 
completed bag made by the young larva, tightly appressed to the flat 
surface, the larva being concealed within. Such bags may frequently 
be found on leaves, and 
are quite puzzling to the 
uninitiated until the 
larva pokes out its head 
and slowly walks off. 
As the caterpillar grows 
the case is constantly 
enlarged, bits of twigs 
and any other small 
objects being used to 
ornament the outside, 
and these objects will 
vary with the kind of 
tree upon which the 
caterpillar is feeding. 
While the larva is small 
it carries its case erect, 
but when it is larger the 
case hangs down (fig. 1). 
The larval skin is cast 
four times, and during 
the molting the mouth of 
the bag is kept closed 
with silk. There is a Fic. 4.—a, Newly hatched bagworm before making its case; 
small opening in the b, same just beginning case; c, showing case nearly com- 
: 2 pleted; d, completed case, insect concealed within; e, larva 
extremity at the bag after first molt. Highly miaenided (original). 
through which excre- 
ment and cast skins are pushed. The male bags are smaller than those 
of the females, reaching a length of about an inch, while those of the 
females are much larger. Toward the end of August, about Wash- 
ington, D. C., the larva completes its growth, attaches its bag firmly 
by a silken band to a twig, strengthens it inside with an additional 
layer of silk, and within this retreat, which now becomes its cocoon, 
transforms to pupa with its head downward. The pupal period lasts 
about three weeks, and then the imago emerges. The male chrysalis 
works its way out of the lower opening, and the winged moth issues 
20833—Cir. 97—08——2 . 
