124 N^W YORK STATE MUSEUM 



and in New York city and vicinity it finds ample opportunity to inflict 

 considerable damage on valuable trees. It manifests a great liking for 

 certain evergreens and as these are usually killed with one defoliation, there 

 is need of watching them closely. A study of the insect shows it to be one 

 of the most interesting forms in our native fauna. 



The conspicuous larval cases or bags reveal the identity of the depre- 

 dator or excite the wonder of the curious, and examples of these are 

 received yearly, some with accounts of serious injury, and others with a 

 query as to the nature and origin of the curious structures. 



Description. The larval case or bag of this insect is usually the first to 

 attract notice. It is a fusiform structure from i^ to 2^^ inches long and 

 in fall and winter it is firmly attached to a twig by a broad band of silk, as 

 shown at figure lo on plate 8. The form of the bag is quite character- 

 istic but as this shelter is covered with particles of bark, pieces of leaves, 

 leaf stems, etc., from the tree on which the larva feeds, its appearance may 

 vary considerably. A female case cut open in late fall or winter presents 

 the appearance shown at figure 1 1, plate 8. Within is the black pupal case 

 and inside that there is a soft yellowish down and a large number of 

 yellowish eggs, a few of which are shown enlarged on the same plate at 

 figure 12. The appearance of the young larva and the cases formed a little 

 later are exceedingly well shown at figures 13, 14 and 15 on plate 8. 

 Special attention should be called to the harmony in color existing between 

 the small cases and the portion of the twig on which they occur, due as 

 determined by Mr Joutel, to the larva gnawing particles from the bark to 

 attach to its tiny case. The full grown larva removed from its protecting 

 bag is shown at figure 16 and the creature's method-of carrying its appar- 

 ently cumbersome retreat is represented at figure i 7. The pupal cases of 

 the two sexes are shown at figures 18 and 21 and the wide difference 

 between the adult insects at figures 19 and 20. The female is almost 

 legless, wingless and nearly helpless, while the male is a small black moth 

 with well developed wings and beautiful feathery antennae. 



Life history. The eggs survive the winter within the larval and pupal 



