INSECTS AFFECTING PARK AND WOODLAND TREES 4 1 7 



The pupa is very thick, the thorax being unusually swollen. The 



body, soon after changing, is a pale horn color, striped with brown ; 



antennae and legs dark-horn color or dull tan brown. The moth has been 



described by Clemens as follows : 



Fore wings brown, varied with dark brown, short striae. The basal 

 patch is indicated by dark brown striae, but the central fascia is not 

 indicated. Following the basal patch is a grayish brown space having 

 a shining luster; its exterior edge is irregular and it widens toward 

 the dorsal margin, where it bears short, dark brown striae. About the 

 middle of the costa is a round spot of the same hue and luster, and along 

 the terminal margin is a stripe with irregular margins, of the same hue and 

 luster bordered on each side with dark brown. Sometimes the grayish 

 luster is absent on the markings, which are then simply of a paler brown 

 than the general hue ; hind wings dark fuscous. 



Life history and\ habits. Dr Packard states that injured trees look as 



though a light fire had passed through them. The larva feeds on the 



leaves or needles of the terminal shoots of both the first and previous 



year's growth. It gnaws the base of the needles, separating them from the 



twig, meanwhile spinning a silken thread by which the needles and bud 



scales are loosely attached to the twig. The caterpillar moves about 



freely and does not live in a regular tube, though sometimes it draws 



together two adjacent shoots. Its presence is hardly noticeable till the 



caterpillars are abundant enough to partly defoliate trees. They are 



usually most numerous in June and early July, occurring on firs and 



hemlocks, in addition to spruce. The caterpillar attains full growth from 



about the 20th to the 30th of June, at which time it transforms to the pupa 



in its rude shelter or hiding place under the loose leaves of the infested 



shoots, and about six days later the parent insect appears. The pale green, 



scalelike, flat eggs are laid in patches, the eggs overlapping each other 



irregularly, leaving about a third or fourth of the surface of each exposed. 



Hatching occurs in about 10 days, and the young caterpillars feed for a 



while and pass the winter in a partly grown condition among the terminal 



shoots of the tree, completing their transformations the following June and 



July. Professor Fernald bred from this caterpillar a parasite, Pimp la 



