504 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



It is a native insect and is found generally over the country 

 east of the Rockies and south of the northern tier of States, but 

 injury is most serious in the Central States. 



Injury is usually sporadic, occurring for a year or two and 

 then disappearing. This is due to the subjection of the insect 

 by its many parasites which keep it from being at all times a 

 first-class pest. 



The male moth is a small, black form with short, rounded, 

 clear wings and is rarely seen. The female is wingless and does 



FIG. 430. Bagworm, Thyridopteryx ephemerceformis: a, larva; 6 and c, pupa, 

 side and back views; d, adult; e, case containing the eggs; /, larva in 

 case; g, eggs. Natural size. (After Forbes.) 



not leave the bag or cocoon. In this cocoon, in the fall, she lays 

 her eggs and in this state the winter is passed. In early spring 

 the eggs hatch and the young larvae feed on foliage, forming 

 almost immediately their bags or cocoons which they enlarge as 

 they grow. The cocoons are first the shape of tiny cones which 

 project from the upper surface of the leaves upon which the insects 

 are feeding and conceal all but the head and feet of the worm. 

 When the insect is nearly grown it begins to taper the lower end of 

 the cocoon and by the time growth is completed the cocoon tapers 

 about equally toward each end, being spindle-shaped. It is at- 

 tached firmly by a band of silk to a small twig and the larva pup- 

 ates. Males emerge in a few weeks but the females remain in the 

 bags and produce their eggs. 



