THE RUST AMONG THE COTTON. 155 



it renders the taking in of new land perfectly superfluous, 

 unless we increase our workers. The continual fertility of the 

 land will prevent a stagnation in the growth of our crops ; 

 there will be little or no disease among them, and especially 

 the rust of the cotton plant will seldom appear, and only then 

 when the unfavorable seasons produce it. 



Such a rotation of our crops has another most salutary 

 and remunerating influence upon our cotton field it will most 

 certainly diminish the ravages of the boll-worm, and the ene- 

 mies of the cotton plant in general. The boll-worm is a cater- 

 pillar, the Iarva3 of a lepidopterous insect or butterfly of the 

 night-swarming family, called Noctua, which, as all the insects 

 of that tribe, undergo, after having been hatched, three dis- 

 tinct metamorphoses, or changes. The insect originates in the 

 form of a small egg, not near as large as the head of the small- 

 est pin ; the hatching of this egg, after a few days, produces 

 the worm or caterpillar ; this, when full grown, changes into 

 a chrysalis or cocoon, and this, after ten or twelve days, is 

 transformed into the perfect insect, butterfly or noctua. The 

 individual natural history of the boll-worm is as yet very 

 little known, but having the generalities of its nature in com- 

 mon with other insects of the same tribe, which are better 

 known to entomologists, it must be, during the winter and 

 the whole time when there is no food for it, either in the 

 state of an egg, which is indeed most probable, or in the state 

 of a chrysalis or cocoon ; it can possibly not hibernate as a 

 perfect insect or butterfly, not finding any food until late in 

 summer. The eggs or cocoons that hibernate must be hidden 

 in the neighborhood where the perfect insect lived, conse 

 quently in the cotton fields or near them. If such fields are 

 not planted again in cotton next spring, the largest number 

 of the brood must necessarily perish, the little caterpillars 

 not finding any aliment suitable for them, and not being able 



