. Circular. Insects. the circle is complete. Then row after row of fragments is added until the case becomes a hollow cylinder (lig. 4, c). One end is then closed up and the inside lined with a tough coating of silk, the case being then extended upright and fastened at 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 qu
. Circular. Insects. the circle is complete. Then row after row of fragments is added until the case becomes a hollow cylinder (lig. 4, c). One end is then closed up and the inside lined with a tough coating of silk, the case being then extended upright and fastened at 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 (tig. 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 small opening in the extremity of the bag 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. Fig. 4.—a, Newly hatched bagworm before making its case; b, same just beginning case; c, showing case nearly com- pleted; d, completed case, insect concealed within;
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectinsects
