276 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



in the second generation a sufficient number of worms to attract general 

 attention. In this case the fourth brood will constitute the third crop, 

 and there will remain sufficient time for the development of one or two 

 later broods. As already explained, these broods are small and attract 

 little attention. Kevertheless, the disappearance of the last brood is 

 one of the most important points in the life-history of the cotton-worm. 

 It is here that we may hope to learn much on the long-disputed point 

 as to whether the species dies out each year in the United States or not. 

 I regret that I have not been able to make personal observations on 

 this point, as my stay in the field extended only to the first of October. 

 Fortunately, careful notes bearing on this subject were taken by Prof. 

 E. A. Smith, at Tuscaloosa, Ala., and by Prof. I. E. Willet, at Macon, Ga. 



From these notes and from other material given in the special report, 

 we feel warranted in stating the following conclusions respecting the 

 disappearance of the last brood of worms : In making preparations to 

 undergo their transformations, individuals of this brood do not differ in 

 habits from those of the preceding broods, except that, as the foliage of 

 the cotton is frequently destroyed, it becomes necessary for the worms 

 to seek other places in which to web up. Thus we see the worms web- 

 bing up, not only in the leaves of cotton, but in the leaves of any plant 

 that they can find, and even in the crevices of bark of trees, ^o tend- 

 ency on the part of the worms to make a denser cocoon than those of 

 the preceding broods was observed. A large part of the pupae, which 

 were enveloped in leaves of cotton, became exposed and fell to the 

 ground owing to the consuming of the leaves by other larvae. Many 

 such pupae would naturally fall prey to predaceous insects or be de- 

 stroyed by other causes. Thus we find, as with the third crop, that a 

 large proportion of this brood is destroyed in a very short time after 

 assuming the pupa state. The length of time "which individuals of this 

 brood remained in the pupa state varied greatly ; many moths emerged 

 early in October, and a few emerged each day till the latter part of the 

 month, when heavy frost occurred. The only instances of moths emerg- 

 ing fi?om the pupae state after a heavy frost, of which we have been able 

 to learn, are those mentioned in Professor Smith's letters of October 26 

 and ISTovember 4, and in Professor Willet's letter of December 11.* 

 Professor Smith also wrote, December 30: "All the chrysalides which I 

 have examined are dead, so that not many, if any, will sui-vive the 

 winter." 



First appearance. — ]5s^o point in the life-history of the cotton- worm 

 is of higher interest than the first appearance of the insect in the spring. 

 Kot only may we expect to learn here important facts bearing upon the 

 question of hibernation of the species in our territory, but other facts 

 which will be of service to us in our efforts to devise some way in which 

 to check the increase of this pest as soon as it appears. The general 

 impression has been that the earliest appearance of the worms in the 

 cotton fields was during the latter part of June or in July. This has 

 been urged as a proof ot'the theory that the si)ecies dies out each season 

 in the United States, and, what is much more serious, this idea has 

 influenced the planters to neglect making any efforts to destroy the 

 worms early in the season. 



Although vigorous efforts were made to collect specimens of the moth 

 early in the spring, none were observed. Baits of various sweetened 

 mixtures were exposed; these attracted many moths, but none of 

 them were Aletia. Neither did any specimens of the cotton-moth 



* See special report. 



