FISHERIES, GAME AND FORESTS. 36 1 



bending its head downward (Fig. 3 b), makes a dive under it, turns a complete som- 

 ersault and lies on its back, held down by the band (Fig. 3 c). By a quick turning 

 movement the larva regains its feet, the band now extending across its neck (Fig. 

 3 d). It then adds to the band at each end until the two ends meet, and they are 

 then fastened together so as to form a kind of narrow collar which encircles the 

 neck of the worm. Far from resting, it now busies itself by adding row after row 

 to the anterior or lower end of the collar, which thus rapidly grows in girth and is 

 pushed further and further over the maker (Fig. 3 e). The inside of this bag is now 

 carefully lined with an additional layer of silk, and the larva now marches off, carry- 

 ing the bag in an upright position." The case is carried in an upright position for a 

 time but as it becomes heavier it is allowed to hang down (Plate 1, figure 17). Holes 

 are eaten out of the leaves (Plate I, figure 15) as the larvae increase in size and pieces 

 therefrom are attached to their protective covering. The cases are enlarged from 

 time to time to meet the requirements of the growing caterpillar. The peculiar, 

 ragged appearance produced by half grown bag worms is shown on the leaf just 

 below figure 22, plate 1. The caterpillars attain their full size in July or August 

 and in early September they become restless and wander to other trees and shrubs. 

 Next the bags are securely fastened to twigs (sometimes the males attach their bags 

 to leaves) by broad bands of silk (Plate 1, figure 10), and the caterpillars then trans- 

 form to pups and about three weeks later assume the adult form. The males are 

 on the wing during September and October. Their appearance is preceded by the 

 male pupa wriggling itself partly out of the larval case, thus permitting the occu- 

 pant to escape direct from his pupal case to the free air, see plate I, figure 22. The 

 female does not leave hers till after ovipositing but works out of her case far enough 

 to permit pairing, returns, oviposits and then escapes from the case and dies. The 

 posterior portion of the pupal shell, which is the upper part as it hangs, is filled with 

 eggs, and the anterior or lower part with the yellowish downy substance which is 

 also intermixed with the eggs to some extent. The eggs may be found the latter 

 part of October and the winter is passed in this form, as previously stated. 



Food plants. This caterpillar feeds on a number of trees and shrubs, but it is 

 most injurious to evergreens on account of their not withstanding defoliation dur- 

 ing the growing season. This insect is specially injurious to arbor vitae and red 

 cedar. It has been recorded on the following trees, beside those previously men- 

 tioned : Apple, pear, plum, cherry, choke cherry, apric ">t, quince, linden, catalpa, 

 maple, locust, oak, elm, poplar, sycamore, osage orange, willow, spruce, hemlock, 

 larch and white pine. 



Distribution in the United States. This species is stated by Dr Riley to occur in 



