26 REPORT UPON COTTON INSECTS. 



The 1840 invasion called forth a great many newspaper articles, which 

 failed, unfortunately, to advance the sum-total of our knowledge to any 

 great extent. Specimens were sent this year to Harris, but he was un- 

 able to do more than mere classificatory work upon them. In the fall 

 of 1840, Mr. Affleck, in the letter already quoted from,* gave the first 

 hint at the migration theory which has recently occupied so prominent 

 a place in all researches on the cotton- worm. Early in 1847 Dr. Gor- 

 ham,t having arrived independently at the conclusion that we have an 

 influx of the moths every year from more southern countries, published 

 a paper upon the subject. In this paper he gives the first notice of a 

 parasite upon the chenille, and draws up a description of what is un- 

 doubtedly Pimpla conquisitor. Mr. Affleck observed this parasite two 

 or three years later, and figured it in 1851. t Dr. Gorham's article excited 

 a real interest. It was reprinted in several prominent Southern journals, 

 and was answered by several writers. No one seemed, however, to agree 

 with his views on migration until the theory was again independently 

 proposed by Dr. W. I. Burnett in 1854. Among all these discursive 

 writings there was, however, so much of a fallacious nature that the 

 good which they accomplished was reduced to the minimum. 



The prevalence of parasites towards the close of this year (1840) is a 

 point worthy of note. Dr. Gorham came to the conclusion that not one 

 of the last brood of caterpillars escaped parisitism, and to account for 

 their appearance the ensuing year was obliged to originate his migra- 

 tion theory. 



In spite of this wonderful abundance of parasites, however, the worms 

 were on hand bright and early in the summer of 1847. Their first ap- 

 pearance was simultaneous in Northern Florida and Southern Louisiana. 

 They appeared early over a large part of the cotton belt, and were found 

 in great numbers as far north as Southern Arkansas ; 1847 was, how- 

 ever, in nearly every cotton State, an unfavorable year for cotton, on 

 account of drought with an occasional heavy storm. The same causes 

 which affected the cotton had their effect also upon the caterpillar, and 

 its insect enemies were enabled to get the upper hand. The result was, 

 that, instead of the year being more severe than 1840, as it at first bid 

 fair to be, it was a marked one in but few localities. In Florida, where 

 the worms were first seen in early July, the damage was so slight as to 

 cause a return of " no injury." The principal ravages occurred in North- 

 ern Louisiana and Southern Arkansas. Carroll Parish, Louisiana, reports 

 them as " very bad," and Miller County, Arkansas, reports a loss of two- 

 corn, and the work of all his people for about fivedays. This gentleman was aroused 

 to unusual action by the reflection, founded on analogical reasoning, that, of one moth 

 of feeble wing and tender body, which a vigilant eye might discover and destroy, the 

 progeny in six weeks amounted to at least twenty millions of worms." (Figures too 

 high.) 



* American Agriculturist, vol. v, p. 342. 



tDe Bow's Review, III, pp. 535-543. 



t Southern Rural Almanac, 1851, p. 50. 



$Proc. Bost. Soc. Nat. Hist., 18'4, vol. iv, pp. 316-319. 



