ATTACKING THE LEAVES. 



273 



yellow and withered. When partly grown, they separate, 

 each one choosing his own coarse, and by this time their 

 digestive powers have become sufficiently strong to enable 

 them to eat freely of all parts of the leaf. 



The fall-grown caterpillar (Fig. 281, a) is nearly two 

 inches long, and usually of a yellowish color, but the color 

 varies greatly, and in the same brood there may be found 

 with the yellow some straw-colored and others brown, from 

 a light to a very dark shade. On each segment there are a 

 number of yellowish tubercles, from each of which there arises 

 a tuft of hairs of a yellowish or brownish color, sometimes 

 intermingled with a few black ones. The spaces between the 

 segments are crossed by dark-brownish or sometimes black 

 lines, and there is a line of the same color along each side ; 

 the under surface of the body is dark also. When mature, 

 it seeks some sheltered nook or cranny in which to pass the 

 chrysalis state, and, having found a suitable location, proceeds 

 to divest its body of the hairy covering, and with this woven 

 together by silken threads it constructs a slight cocoon, within 

 which the chrysalis is formed, of a chestnut-brown color, as 

 shown at b in the figure. There 

 are at least two broods of this 

 insect each year, and these 

 broods so intermingle that the 

 insect may almost always be 

 found in one or other of its 

 stages from May to October. 



This species is subject to the 

 attack of several kinds of Ich- 

 neumon flies, which destroy im- 

 mense numbers of them every 

 year ; one of these, Ophion bi- 



lineatus Say, is represented in Fig. 282. Were it not for 

 these friendly agencies constantly at work the common woolly- 

 bears would soon become very destructive. As it is, they are 

 sometimes very injurious; when this is the case, hand-picking 



18 



Fig. 282. 



