32 
The larve.—Under ordinary circumstances the larve feed mainly at 
night, or in damp, cloudy weather, remaining hidden during bright 
days, resembling in this habit the closely allied cutworms. They 
reach full growth in three or four weeks, attaining a length of 14 
inches, burrow into the ground, and transform into brown chrysalides. 
In this condition they remain in the summer an average of two weeks 
before yielding the perfect moths. 
Number of generations.—Several generations are produced each sea- 
son; two or three in the Northern States and four or five or perhaps 
six in the Southern States. 
The army worm, as a rule, passes the winter in the half-grown larval 
condition, occasionally in the South hibernating as a moth, and perhaps 
rarely in the egg stage. 
This insect is present in grass land probably every year in greater 
or less numbers, but on account of the habit of concealment of the 
larva it is very rarely noted. It attracts attention and becomes a mat- 
ter of grave concern only when, as a result of a series of favorable 
years or exceptionally favorable local conditions, it suddenly develops 
in enormous numbers and is forced by scarcity of food and hunger to 
migrate in swarms from its breeding grounds, and travels and feeds 
both during the day and night. 
The over-wintered larve appearing suddenly in spring may occa- 
sionally attract notice, but as a rule the notable and destructive swarms 
are the progeny of the first, second, or third summer broods. In gen- 
eral, it may be said that these worms are more apt to make an injuri- 
ous appearance in a rainy spring or early summer following a season 
of comparative drought. This was well illustrated in the case of the 
outbreaks of 1888, and especially 1894. 
PREVENTIVES AND REMEDIES. 
As already noted, the fact that the army worm occurs at very irreg- 
ular intervals—usually widely separated, and as a rule without warn- 
ing—renders it impracticable to get farmers to undertake preventive 
measures. In general, however, it is true that clean cultivation and 
the adoption of a regular system of rotation of crops in which grass 
lands are alternated every few years with cultivated fields will keep 
this insect in check and probably prevent an unusual multiplication of 
it. Bearing in mind also the fact that 1t breeds normally in rank 
grass and over-winters in such situations, it is of importance to burn 
over such tracts early every winter, which will kill many of the larvee 
and leave the others to be destroyed by exposure. If these measures 
be practiced the army worm will probably never be able to get a 
migratory start, or, in fact, become abundant enough to necessitate 
migration. 
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