848 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



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 on which they rest. 



The caterpillars are sometimes i)reyed upon by ichneumons, two 

 small Ichneumonidee having been bred from pupge in confinement. No 

 Chalcid jiarasites 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. 



Larva hefore the last moll. — Body pale green, nearly of the color of the fresh leaves, 

 ■with the head and cervical or prothoracic shield black. Length, lO-ll'i^'", 



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 piliferons 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>"n\ 



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 SQiall down-curved spine on each side ; on the 

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

 are two similar bristles on the under side within the edge of the square tip. Length, 

 8-9™'". 



Moth. — Head white or subocherons ; palpi dull gray, with white scales. Thorax 

 either white and black or reddish ocherous with white scales. Fore wings with the 

 basal third either black, gray, or snow white ; usually dark gray ; on the outer edge 

 of the dark portion are two groups of sharply raised scales. Beyond is an irregular 

 white band, the white sometimes obscured by gray scales ; this band is very irregu- 

 lar in width, being narrow on the costa, widening towards the middle of the wing; 

 it is indented on the inner side at the second tuft of raised scales ; where the band is 

 widest, viz, on the outer edge behind the middle of the wing, is a deep sinus, very 

 distinct in those specimens where the band is white ; on each side of the mouth of 

 the sinus is a sharp tuft of raised black scales, and within (one near the costa) are 

 the smaller tufts. In those specimens in which the rest of the wing is whitish there 

 is a large triangular dark spot, with the base resting on the costa; usually, however, 

 the outer third of the wing is dusky or clear gray, with dark specks and clouds, and 

 the triangular patch is obscured. Sometimes when the wing is clear gray the veins 

 on the outer third are hardly clouded with a darker shade of gray. Hind wings and 

 abdomen slate gray. Expanse of wings, 12-15'"™. 



This is a very variable moth, but the four or five raised tufts are nearly always 

 present. Some striking varieties are here noted: 



(a) Fore wings gray, with a broad whitish-gray band j ust before the middle of the 

 wing; the large dark triangular spot not present. 



(6) The outer third of the wing concolorous with the band, thus leaving a large 

 distinct triangular spot. 



(c) Fore wings snow white at base, with a snow-white band near the base, in the 

 outer edge of which the sinus is very distinct ; the outer third of the wing is either 

 white or blackish. 



