SHADE TREE INSECTS 43 



which gives the insect its common name. The body is striped lengthwise with 

 alternate black and yellow stripes and is thinly covered with long, soft, white 

 hairs but does not have the distinctly hairy appearance of the walnut caterpillar. 

 Conseciuently when it molts it does not leave hairy patches on the tree where 

 molting occurs. 



The pupae are about J/o inch long and dark brown in color. 



Life History. The moths appear in early summer from mid-June through 

 July, and lay their eggs in clusters of 100 or more on the under side of the leaves. 

 The eggs hatch from late July through early August, and the caterpillars begin to 

 feed on the foliage. The newly hatched caterpillars skeletonize the lower sur- 

 face of the leaves, but the older ones devour the entire leaf with the exception of 

 the stem. Like the walnut caterpillars, these also feed gregariously and are often 

 found clustered together in a solid mass en a limb. The caterpillars feed for about 

 a month, maturing from late August into September. When mature they descend 

 to the ground, usually at night, burrow beneath the surface, and transform into 

 pupae without any cocoon. The moths appear the following summer. There 

 is one generation in this section. 



Control. Control measures advised for the walnut caterpillar are effective 

 for this insect. 



Britton, W. E. Conn. State Ent. Rpt. 17:328-329. 1918. 

 Felt, E. P. N. Y. State Mus. Mem. 8(2) :535-536. 1906. 

 Houser, J. S. Ohio Agr. Exp. Sta. Bui. 332:229-230. 1918. 

 McDaniel, E. I. Mich. Agr. Exp. Sta. Spec. Bui. 243:30. 1933. 

 Ruhmann, M. H. Brit. Columbia Dept. Agr. Ann. Rpt. 29:B37-B39. 1935. 

 Sanderson, E. D. N. H. .^.gr. Exp. Sta. Bui. 139:213-215. 1908. 



Birch Skeletonizer 



Biicculatri.K canadensiselln Chambers 



This moth has been found in northern United States and in Canada. In the 

 United States it occurs from Maine to Minnesota and south to North Carolina; 

 in Canada, from New Brunswick west to British Columbia and probably as far 

 north as the Yukon. 



The larvae, or caterpillars, are restricted to the birches and possibly the alder, 

 Alnus incana. The host birches include gray birch, Betula popiilifolia; white or 

 paper birch, B. papyrifera; yellow birch, B. /z(^^a; black birch, B. lenta; and the 

 European white birch, B. alba, the varieties of the last being known as the cut- 

 leaf or weeping birch. 



Since about 1890 severe outbreaks have occurredat intervals of about ten years, 

 when large areas of birches have been skeletonized. Between these outbreaks 

 were years of comparative scarcity. This insect is considered to be chieflj' a pest 

 of woodland trees but when abundant has been known to attack shade trees. 

 The caterpillars feed in late summer on the lower surface of the leaves, preferably 

 the older ones, skeletonizing them. The affected leaves die and drop from 

 the tree. The greatest amount of feeding occurs during late August and Septem- 

 ber at which time the trees have passed through the most active season and thus 

 are not so seriously injured as they would be by a similar attack earlier in the 

 summer or in the spring. 



DescriptioJi. The adult is a very tiny moth, with a wingspread of only 3/8 

 inch. The general color is a bright brown with transversely diagonal, silvery- 

 white bars on the forewings. The wings, especially the hind pair, have broad 

 fringes of hair. 



