FOREST INSECTS AND FUNGI 115 



maple trees. Many sugar orchards were completely stripped 

 of leaves by the caterpillar, resulting in the death of numerous 

 trees, and an injury to sugar productivity which has not yet 

 been fully compensated, after a period of ten years. The defo- 

 liation occurs for the most part in the early summer. While 

 the insect prefers the foliage of the maple, it does not confine 

 its ravages to this tree, but eats the foHage of oak, Hnden, 

 locust, peach, plum, cherry, apple, elm, poplar, birch, and some 

 of the shrubs. 



Appearance. — The damage is done by the caterpillar which 

 is blue-headed, with a line of silvery diamond-shaped spots 

 down the middle of the back. When not feeding, they assemble 

 in clusters on the sides of the larger limbs and trunks. This 

 insect may be distinguished from the common tent caterpillar, 

 Malacosoma americana, by the fact that it does not spin a con- 

 spicuous web tent as does the latter. The egg belts containing 

 about 150 eggs encircle the slender twigs and have a brownish 

 protective covering. The white or yellowish-white cocoons are 

 spun in the leaves on the tree or on the ground, in crevices of 

 the bark, under stones, in fence corners, etc. In the cocoons are 

 dark-brown pupae. The moths are light buff colored and active. 

 The males are smaller than the females and of rich coloring. 



Life History. — This insect passes the winter in the egg stage 

 as a well-developed larva. In the warm weather of spring the 

 young caterpillars emerge and await the unfolding of the leaves. 

 As the young increase in size they molt, leaving their cast-off 

 skins on the bark. The larvae are found in clusters on the 

 limbs when not feeding. When the limb is jarred they are 

 easily knocked off. Early in June when the caterpillars are 

 nearly full grown they may be seen in great numbers crawling 

 over walks, piazzas, and the sides of buildings. The insect 

 remains in the pupa stage about two weeks, and emerges as 

 a moth about the last of June or in July, when the eggs are 

 deposited. 



Natural Enemies. — This insect is sometimes attacked by a 

 fungous disease. It is also a favorite item of diet for robins, 



