18 



silken thread. They are very active in their habit? 

 in tin boxes will squeeze through the narrow space between the box and 

 the cover, so that only an unusually tightly closed box will confine 

 them. Sometimes, at least in two instances, the caterpillars construct a 

 case of the leaves which they had cut off at the end of a fresh bud. 



The caterpillars were very abundant this year in spruce and firs on 

 the shores and islands of Casco Bay, from June 10 until July 20. As 

 full-grown larvae are abundant during the early part of June, it seems 

 that it hibernates among the shoots of the tree during the winter, and 

 that as in the case of the Spruce Bud-worm (Tortrix fumiferana) it 

 hatches in August, or at least late in the summer, and becomes nearly 

 fully grown before cold weather sets in. 



The caterpillar when fully grown is of the usual shape of a leaf-roller, 

 deep green, with a dark reddish head and cervical shield ; before the 

 last molt the head and prothoracic or cervical shield are black. 



From the 14th to the 16th of June the caterpillars change to chrys- 

 alides within the slight white cocoon they spin among the bases of the 

 leaves next to the shoot. The moths begin to issue early in August, 

 and continue to appear until the middle of the month. In one case the 

 insect pupated from July 6th to the 10th, the moth issuing on the 19th; 

 hence the pupal period lasts about two weeks. Others which pupated 

 July 14 to 16 appeared three weeks later. None of the insects lingered 

 in the pupa state beyond the 14th of August. The moths are subject 

 to great variation, the details of which are given in the description. 

 In their color they are assimilated to the moss-covered bark of the 

 larger branches of the trees they rest on. 



The caterpillars are sometimes preyed upon by ichneumons, two 

 small Ichneumonidge having been bred from pupa? in confinement. No 

 Chalcid parasites have yet been observed to prey upon this species. 



Should the worms attack shade or ornamental firs and spruces, they 

 can be subdued by spraying and striking the branches and shoots so as 

 to dislodge the worms. 



DESCRIPTIVE. 



Larva before the last molt. — Body pale green, nearly of the color of the fresh leaves, 

 with the head and cervical or prothoracic shield hlack. Length, 10-1 i mm . 



Full-grown larva. — Body pale pea-green, moderately thick, gradually tapering from 

 the middle to the end of the body. Head of the usual shape, somewhat bilobed, not 

 so wide as the body ; dull reddish amber, or greenish-yellow amber-colored in front ; 

 partly brownish-black behind and on the sides, the black forming two patches on 

 the vertex. Prothoracic or cervical shield black on a greenish ground ; varying to 

 greenish-amber edged behind with blackish ; sutures and lateral ridge slightly tinged 

 with yellowish. On the body-segments the piliferous warts green, not distinct ; 

 arranged as usual in a trapezoid. Thoracic legs greenish amber-colored, first pair 

 larger and darker than the others ; abdominal legs pale green, concolorous with the 

 body. Length, 12-14 mm . 



Pupa. — Body rather slender, the double rows of dorsal spines as usual, but the 

 spines are smaller and not so sharp as usual. End of the abdomen broad, square, and 

 much flattened vertically, with a small down-curved spine on each side ; on the 

 square edge of the tip are from four to six slender, small, curved, stiff bristles. There 



