248 BOARD OV AGRICULTURE. 



The bulk of the worms are full grown, and do the greatest 

 amount of damage, about the time that wheat is in the milk. 

 In ordinary seasons they are reported along the thirty-second 

 parallel, as in Texas, early in March, and about a week later 

 with each degree of latitude as we advance northward ; so 

 that in Maine they often make their first appearance as late 

 as September. 



The worm confines its attacks to grasses and cereals ; and 

 it is extremely doubtful whether it could live for an}^ length 

 of time on other plants. Its more natural food-plants are 

 the coarse swamp-grasses. Of cultivated crops it does most 

 injury to Timothy, blue-grass meadows, and winter wheat. 

 Though the worms will nibble at clover, they are evidently 

 not fond of it, and generally pass it by. Rye, also, is not 

 so palatable to them as some of the other grasses. They 

 often cut off the ears of wheat and oats, and allow them to 

 fall to the ground, and are doubtless led to perform this wan- 

 ton trick by the succulence of the stem immediately below 

 the ear. South of latitude forty degrees, they generally 

 appear early enough to materially injure the crop ; but north 

 of that line wheat is generally too much ripened for their 

 tastes, and is sometimes harvested before the full-grown 

 worms make their appearance. 



There are two facts in the history of the army-worm, 

 which create most astonishment in the minds of those un- 

 familiar with its habits. These are, its sudden appearance 

 over large stretches of country, and its equally sudden dis- 

 appearance at the height of its destructive career. It is a 

 well established fact that all army-worm years have been 

 unusually wet, preceded by one or more exceptionally dry 

 years. Bearing in mind that the insect is with us every 

 year, and that its favorite abode is in low prairie-lands and 

 swampy meadows, we can understand how, during very dry 

 seasons, when these lands dry out to a greater extent than 

 usual, the range of the worm is extended, and the conditions 

 for its development particular!}^ favorable. Should the suc- 

 ceeding season prove very wet about the time the moths 

 oviposit, they would naturally be driven from all land low 

 enough to be submerged, and forced to consign their eggs 

 to higher grass-lands, wliich the copious rains would render 

 sufficiently wet to suit their habits. 



