ATTACKING THE LEAVES. 



207 



Fig. 213. 



cles. After it has passed the second moult it appears as seen 



at a. From the end of August until late in September it may 



be found full grown^ when it measures two inches or more in 



length and about half an inch, in diameter^ and presents the 



appearance shown at b in Fig. 213. It is of a bluish-green or 



sometimes of a greenish-yellow 



color^ with the head, feet, and 



hinder segments yellow. There 



are about eight small warts or 



short horns of a deep-blue color 



on each segment, except the 



two uppermost on the top of 



the third and fourth segments, 



which are of a rich coyal-red 



color, and a long one on the Nn 



top of the twelfth ring, which 



is yellow. 



The caterpillar is found feed- 

 ing on the cherry, ash, sassafras, 

 poplar, azalea, cephalanthus, or 

 button-bush, and other shrubs 

 and trees. Although the ash 

 is a very common food-plant 

 for the larva, it is rarely, if 

 ever, that a cocoon is found 

 upon it; the leaf-stalks being 

 so very long, it is probably too laborious a task for the cater- 

 pillars to fasten them to the twigs, and hence they wander off 

 in search of leaves with shorter stalks and of a thicker, more 

 leathery structure, such as the cherry or the lilac, which form 

 a substantial covering for the cocoon. 



The cocoons are often perforated by birds during the winter 

 and their contents devoured. The insect is also subject to 

 the attacks of a small four-winged parasite, a species of Ich- 

 neumon. 



