HABITS OF THE ARMY-WORM. 247 



sumed. The chrysalis is normally assumed in a simple cell 

 in the ground. 



Although the travelling of the worms in large armies is 

 generally considered one of the principal characteristics of 

 this insect, it is nevertheless abnormal. During the latter 

 part of April, and throughout the month of May, in latitude 

 thirty-nine degrees, the worms may almost always be found 

 by diligent search in moist grass-land that was not cut or 

 grazed too closely the previous autumn. At such times they 

 have essentially the habits of ordinary cut-worms, and are 

 seldom noticed, unless so abundant as to cut the grass en- 

 tirely down, and be obliged to migrate to fresh pastures. 

 Indeed, one may pass daily through a grass-plat where they 

 abound, yet never suspect their presence until the plat sud- 

 denly begins to look bare in patches. 



There are two reasons why they so easily escape detection 

 in this their normal condition. First, when less than half an 

 inch long, they are not recognizable as army-worms, except 

 to those who reared them from the Ggg. The characteristic 

 dark sinuous lines on the head, and the vittse along the body, 

 are at this time more or less obsolete, and the general color 

 is paler. Second, they feed mostly at night, and hide during 

 the day at the base of the grass, or under any other shelter 

 at hand. If they venture to mount to feed during the day, 

 — which they often do in cloudy weather, — they drop at 

 the least disturbance, and curl up in a spiral, so as to simu- 

 late very closely a small shell of the helix form. The worm 

 loves cool, moist places, and is more often found around the 

 margins of creeks and ponds than elsewhere. As already 

 intimated, it is only when hunger impels them, that they 

 vacate the fields where they are born ; though, after they have 

 once begun the wandering habit, they will often pass through 

 fields without eating every thing to the ground. When 

 travelling, the worm will scarcely turn aside for any thing 

 but water, and even shallow water-courses will not always 

 check its progress ; for the advance columns will often con- 

 tinue to rush headlong into the water until they have suffi- 

 ciently choked it up with their dead and dying bodies to 

 enable those in the rear to pass safely over. I have also 

 noticed, that, after crossing a bare field or road where they 

 were exposed to the sun's rays, they would congregate in 

 immense numbers under the first shade they reached. 



