INSECTS INJURING SPRUCE. 



855 



Fig. 287.— Single 

 pierced cone (orig- 

 inal). 



The Spruce Oone-worm is usually conflned to the young cones, into 

 which it bores and mines in different directions, eating 

 galleries passing partly around the interior, separating 

 the scales from the axis of the cones (Fig. 287). After 

 mining one cone the caterpillar passes into an adjoin- 

 ing one, spinning a rude silken passage connecting the 

 two cones. Sometimes a bunch of three or four cones 

 is tied together with silken strands ; while the castings 

 or excrement thrown out of the holes form a large, con- 

 spicuous light mass, sometimes half as large as one's 

 fist, out of which the tips of the cones are seen to pro- 

 ject (Fig. 288). Besides these unsightly masses of cast- 

 ings, the presence of the caterpillars causes an exuda- 

 tion of pitch, which clings in large 

 drops or tears to the outside of the 

 adjacent more or less healthy cones. 

 Where much affected the young 

 cones turn brown and sere. 



The same worms had also attacked 

 the terminal branches and twigs of 

 the same tree, eating off the leaves 

 and leaving a mass of excrement on 

 one side of the twig, within which 

 they had spun a silken gallery in 

 which the worm lived. 



On removing the bunches of dis- 

 eased cones to Providence, one cater- 

 pillar transformed in a warm cham- 

 ber into a moth, which appeared the 

 end of October; its metamorphosis 

 was probably accelerated by the un- 

 usually warm autumnal weather. 

 All the others had by the 1st of 

 November spun within the mass of 

 castings a loose, thin, but firm, oval 

 cocoon, about half an inch long and 

 a quarter of an inch wide, but the 

 larviie had not yet begun to change 

 to chrysalids. Whether in a state of nature they winter over in the 

 larval state within their cocoons, or, as is more likely, change to pupoe 

 in the autumn, appearing as moths by the end of spring, remains to be 

 seen. 



The chrysalis is of the usual Phycid appearance, rather slender, but 

 with the abdominal tip blunt, with no well-marked cremaster or spine, 

 though ending in the usual six curved stiff bristles, by means of which 

 it hooks on to the walls of its cocoon, thus maintaining itself in its nat- 

 ural position. 



Fig. 288. — Mass of infested cones (original). 



