120 REPORT UPON COTTON INSECTS. 



have shown in the chapter on Natural History that the first brood is 

 developed in May, as soon as the cotton plants furnish sufficient food. 

 And there is no doubt in our opinion that the inoths, which Mr. Grote 

 observed to be attracted to light in houses in June or July and which 

 he supposed " heralded " the appearance of the first brood of worms, 

 had been developed the same season in neighboring cotton fields. It 

 will be remembered that all efforts to obtain inoths in the early part of 

 the past season failed, though the presence of full-grown worms on 

 cotton in the latter part of May indicated that moths had visited the 

 fields several weeks earlier. It is not strange that Mr. Grote failed to 

 observe the larvae of the first brood ; for, doubtless, he was led by the 

 universal testimony of the planters to expect them at a much later sea- 

 son than that at which they occur. Moreover, it is not an easy task to 

 find the larvae in May, even when a person is looking for them, they 

 occur in such small numbers. Mr. Grote is also mistaken in supposing 

 that worms are always reported southward of any given locality before 

 they are found north of it ; as a study of the past history shows, it has 

 not been an uncommon thing for cotton- worms to be reported in Central 

 Alabama earlier than in the southern part of the State. As to the sup- 

 posed absence of parasitic checks we will simply refer to our remarks 

 on Dr. Gorham's paper, and to the chapter on Natural Enemies, where 

 the subject is discussed at length. 



It seems to us that when we have weighed carefully the data upon 

 which the theorists have based their conclusions, there remains but lit- 

 tle reason for a discussion of the theory. All the supposed facts which 

 have been brought forward to support it, with a single exception, have 

 proven to be mistaken ideas. The moths are evidently capable of mak- 

 ing long flights, as is shown by their occurrence in the autumn several 

 hundred miles north of the latitude in which they can survive the winter. 

 But this alone is not sufficient to prove the theory. It simply shows 

 that did the moths occur in large numbers within an equal distance south 

 of our territory we would be liable to suffer from incursions of the pest 

 from those regions. But it remains to be proven that the presence of 

 moths in our country is dependent upon such incursions: Mr. Schwarz 

 has shown in his report* that there can have been no invasion of the 

 moth from the Bahamas since 1866. And it can hardly be supposed that 

 moths have come to us from the islands .south of the Bahamas since that 

 date, for in that case the latter islands would have been restocked with 

 worms by some of the migrating individuals on the passage to this coun- 

 try. With regard to the possibility of receiving moths from Cuba, we find 

 that, although cotton is indigenous there, very little is grown ; and, too, 

 there is no evidence of an excessive multiplication of the cotton-worm 

 on the island. In a collection of insects injurious to cotton made by my 

 friend Mr. B. W. Law, near Havana, not a specimen of Aletia was found. 

 Hence we cannot believe that since the year 1866 our country has buf- 

 fered to any great extent by immigrations of inoths from the West Indies. 



* Appendix I. Report of E. A. Schwarz. 



