ENEMIES OF PLANTS. 329 



marked with a row of white spots instead of a 

 continuous line of white, as in the americana. 

 In the colonies or masses which they form 



FIG. 119. FOREST TENT-CATERPILLARS FEEDING UPON ELM LEAVES. 



when not feeding there is a more or less dis- 

 tinct web underneath them, but it does not form 

 a complete covering above them, as in the 

 americana. They not only eat away consider- 



