54 i .NEW JERSEY AGEK'ULTUEAL COLLEGE 



to maliogaiiy brown pupae about tAvo inches below tbe surface — less 

 in summer tJian in late fall, wlicn thev usually go nearer the frost 

 line. In from one to two Aveeks afterward the adults make their 

 appearance and soon thereafter another life cycle begins. Under 

 ordiimry circumstances, six weeks from the egg to the resulting 

 adult nuiy be considered about normal, but in midsummer the 

 period may be shortened to a month, and in cool weather may be 

 lengthened to nearly double that time. Three broods during the 

 season are usual, although there may be a partial fourth, which 

 matures so late that many of the pupve hibernate. 



It is rare for the spring brood to be sufficiently numerous to 

 become noticeable, and even the second or early summer brood 

 rarely attracts much attention, but in late summer, when the third 

 brood in a favorable season becomes half grown, they are present in 

 such, enormous numbers that in a few days an entire field is cut 

 down and a march is begun. These "armies" on the march follow 

 no order or system ; it is merely a search for food, and each indi- 

 vidual halts as soon as it has found something to feed upon, resum- 

 ing its place in the line as soon as hunger can no longer be satisfied. 

 While they occur in moderate numbers the larvse usually feed at 

 night and hide at the base of the plants during the day, but when 

 their numbers become so great that the food-supply is scant they 

 eat at all times when opportunity offers. 



Remedial Measnresi 



It has been stated that the adult usually lays its eggs in the 

 densest and rankest part of a grain or grassfield, and it is from 

 such spots that tlie insects usually spread or from which an "'army'^ 

 starts. When such an infested patch is discovered, it should be 

 isolated at once by plowing a deep furrow completely around it, 

 steep side outward. If the furrow is imperfect, mend with a spade 

 so that the caterpillars may find it impossible to crawl out. A 

 ditch may be dug instead, if more feasible. At intervals of ten feet 

 or thereabouts drive post holes or dig a deeper hole. The cater- 

 pillars having entered the furrow or ditch, and finding it difficult 

 to scale the further side, naturally crawl along the bottom until a 

 post hole is reached. They tumble into that and are then utterly 

 unable to escape. To prevent any from maturing, kerosene may be- 



