Packabd.] insects of the FIELD. 219 



of all their leaves. There were no worms upon the potato 

 tops, though they have killed all the grass to the borders of 

 the field." 



The name "Army worm" is suggestive of the regular, 

 trained way in which myriads of these caterpillars march 

 together in long, deep columns, side by side, steadily over 

 every obstacle, wherever their food or instinct may lead 

 them. Unlike the cut worms, which move by night, singly, 

 from field to field, and secrete themselves by daytime at the 

 roots of the plants they attack, the* Army worm feeds in the 

 forenoon as well as the evening. They may be seen scat- 

 tered over fields of grain or grass, either devouring the 

 leaves or cutting off the heads and letting them fall on the 

 ground. They will thus eat their'way across a field, wan- 

 tonly mowing off the heads of the grain. In this way in 

 Plymouth county, Mass., they destroyed an acre and a half 

 of wheat in one night, and then attacked a corn field in the 

 same ruthless manner. 



This caterpillar appears first in July in Massachusetts, 

 and a month later in Maine, where we saw it at Bangor and 

 northward between the first and middle of August. 



It is about an inch and a half long, like the cut worm in 

 shape. It is dark, with a light, interrupted, thread-like line 

 along the middle of the back ; on the sides a light line edged 

 with two thread-like lines, and a light colored, waved line 

 just above the legs. ^ 



About the middle of August it descends into the earth, 

 and there constructs a rough earthen cocoon, or contents 

 itself with making a rude cell of dry grass just below the 

 surface, in a day or two after assuming the chrysalis state. 

 Lying here for ten days or a fortnight, the moth flies about 

 at the end of August. 



In dealing with this insect, the best remedy is of a pre- 

 ventive nature. If the grass lands and wheat fields are 

 bui'nt over in autumn multitudes of the moths, or chrysal- 



27 



