MARCHING OF THE WORMS. 91 



destroyed, or before the cotton has reached a stage of maturity, after 

 which the eating of the foliage by the worms is not considered a calamity. 

 In some instances the first crop of worms is doubtless the second brood 

 of the season ; in some instances it is not until the third brood is pro- 

 duced that the worms are of sufficient numbers to be observed, and thus 

 designated as a crop. 



The term "crop of worms" has become thoroughly incorporated in 

 the language of those most interested in the cotton-worm; and, more- 

 over, it is a very convenient term. We shall therefore adopt it ; em- 

 ploying it, however, in the sense in which it is generally used. Thus, by 

 first crop of worms we shall mean not the first brood, but the earliest 

 brood that is of sufficient size to be easily noticed ; and the second and 

 third crops are the two broods immediately following the first crap. 

 The term brood will be used in its usual sense. 



DISAPPEARANCE OF THIRD CROP. 



While contemplating, in the autumn of 1878, the immense number of 

 worms which constitute the third crop, I was struck with the fact that 

 if even a thousandth part of the worms were to mature and survive the 

 winter the second brood in the spring would be of sufficient numbers 

 to destroy the cotton crop. I was therefore interested in watching the 

 disappearance of this so-called third crop. 



The result of these observations shows that when the cotton-worms 

 occur in sufficiently great numbers to strip the cotton of its foliage the 

 greater part of that brood perishes at once. 



When the leaves of the cotton are destroyed the worms are forced to 

 migrate in search of more food ; or, if they are fully growu, as is often 

 the case, in search of places in which to undergo their transformations. 

 While at Faunsdale, Marengo County, Alabama, August 28, 1878, I 

 was fortunate enough to witness an attempted migration of this kind r 

 which was attended with astonishing results. 



As soon as the larvae left the cotton stalks they experienced great 

 difficulty in crawling over the surface of the ground. Clinging hold of 

 the loose particles of earth by its prolegs, a larva would attempt to 

 stretch its body forward in the manner peculiar to " loopers," but no 

 sooner was the anterior part of its body raised from the ground than 

 the insect, unable to balance itself upon the crumbling bits of earth, 

 would fall to one side with the full length of its body upon the ground. 

 Had it been a cloudy day, or had the ground been shaded, this would 

 not have been so serious a matter to the larva; but, as is ususilly the 

 case at that season of the year, the sun was shining with an intense heat 

 and the surface of the soil was as hot as the sides of an ovc:i. The 

 larvae did not seem to suffer so long as they were resting with tl.eir legs 

 upon the ground, but no sooner did one of them fall so as to touch the 

 earth with its body than it began to squirm violently. Sometimes a 

 larva would regain its position upon its legs, but the first attempt at 



