18 PEEFACE. 



States is, as may be imagined, from their immense 

 extent, very great, aside from such occasional severe 

 visitations as that of the grasshoppers in the West. 

 Yet it is difficult to give any exact calculation in 

 figures of the amount of damage thus inflicted. 

 Take the case of the Cotton-Worm, with which I 

 became familiar from observing it for several years 

 upon my own and my mother's plantations in 

 Central Alabama, and which, being one of the Noc- 

 tuidse, is pertinent to the subject of this Essay. 

 This insect spreads during the season, from south 

 to north, over the cotton-growing region from 

 Texas to the Ohio E-iver. The larva strips the 

 plant of its foliage, and, where it occurs in force 

 early in the season, and remains in the locality 

 through successive broods, it inflicts great damage, 

 eating finally the flowers, the soft bolls, and cutting 

 off the last picking of cotton. Yet its appearance 

 is not uniform over the region ; it rarely greatly 

 increases in number until after the main crop is 

 formed, and where it attacks cotton on bottom 

 lands, growing rank and large, it does but little 

 real harm. By eating the leaves it causes the later 

 bolls to mature more rapidly; while in South- 

 western Georgia and some parts of Alabama, the 

 "rust" (a vegetable parasite, of which we hear 

 comparatively little) is a much worse foe of the 

 cotton-planter than the " worm." It will be readily 

 seen how the injuries committed by any one insect 

 can be over-estimated upon paper by interested 

 parties, when we see how much should enter into 

 the calculation. The historv of the cotton-worm is 



