115 



larval state is of about ten days' duration, and, during this time, they moult two or 

 three times, changing their colors and general appearance in the same singular man- 

 ner as the canker-worm of the North. The caterpillar, when full-grown and well fed, 

 ia sixteen legged, of the size of a common crow-quill, and from an inch and a quarter 

 to au inch and a half in length. It has a reddish head, is whitish below, and brown- 

 ish blaek above ; on each side are two longitudinal, wavy white lines, and another 

 straight on the middle of the back. When, ready to wind up they swing down from 

 the cotton plant, and, without any choice, take up indifferently with the nearest ob- 

 jects, on which they may rest during this process. Their chrysalid state continues 

 about twelve days ; the moths then appear and immediately go about depositing their 

 eggs, after which they die. This perfect state lasts only four or five days. Such is 

 the routine of their reproduction. When they appear early in the season, there are 

 usually three broods ; but some years they come so late that only a single new gener- 

 ation is seen. In either case the last brood almost invariably perishes throughout, 

 being either killed instantly by the frost or dying from starvation, having eaten all 

 the cotton before their transformations take place. It follows, therefore, that these 

 ravaging insects as they appear in the cotton fields of the South do so at the loss of 

 that portion of their race, for they leave no progeny behind them. At the same time 

 this condition of things makes the matter the more deplorable for the planter, for, as 

 he has to contend with a suddenly invading foe from foreign parts, he is rendered 

 wholly powerless in averting this regularly periodical destruction of property. 



Dr. Burnett's statement of the theory, being published in a purely sci- 

 entific journal of limited circulation in the South, seems to have failed 

 to attract much attention, as we have been unable to find it mentioned 

 in any of the agricultural journals of that time. Neither do we find any 

 reference to a theory of migrations until nearly twenty years later, when 

 Mr. A. E. Grote, in an article in the Eural Carolinian for November, 

 1871, incidentally made the following statement : 



The question with us has been, where does the first brood come from t The Novem- 

 ber chrysalises all became moths during warmer days, or were finally destroyed by 

 frost or the process of cultivation. On sunny winter days a few of the hibernating 

 moths were seen about fodder stalks. Bnt before the young cotton was large enough 

 to furnish food in the next spring, our cotton-worm had entirely disappeared, nor could 

 we find it in any stage. We always hear of it southwardly from us. We know that 

 the southerly winds bring the moth. Indeed, Professor Packard writes us that ho has 

 found the moth as far north as the coast of Massachusetts. Out of sight of land off 

 Charleston we ourselves have seen numbers of cut-worm moths flying about the ship, 

 blown from the shore. 



It was not, however, until August, 1874, at the Hartford meeting of 

 the American Association for the Advancement of Science, that Mr. 

 Grote put forth the theory in a definite form. Mr. Grote's conclusions 

 were based upon observations made during a residence of several years 

 in Central Alabama, and were published, like those of his predecessors, 

 without any knowledge of earlier writings on the subject. We see here 

 the strange phenomenon of a scientific theory being independently de- 

 veloped and proposed four times in a little more than a quarter of a cen- 

 tury. 



We will quote only that part of Mr. Grote's paper which refers to this 

 theory : 



It is the object of the present paper to throw, happily, some light on the biography 

 of the cotton-worm as it occurs in the Southern States, and in so doing I think it will 



