368 REPOIT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 



bruised spot, which is the first manifestation of the rot, is simply the 

 result of the gnawings of the worm in its attempt to penetrate the boll 

 at that point. Bolls thus spotted were, as he reports, watched until 

 in every case the rot supervened. 



In spite of the confidence with which Mr. Stelle puts forth this theory , our 

 experience would indicate that he is mistaken. In fact we have learned 

 to question the trustworthiness of his statements. We have repeatedly 

 seen bolls badly gnawed both by Aletia and by the Boll Worm, as well 

 as by other Lepidopterous larvae, which yet were sound and good inside, 

 and we believe the cases mentioned by Mr. Stelle to have been simply 

 coincidences. We may also adduce the fact that the gnawings of the 

 worms into tomato and Physalis, fruits which rot very easily, seldom if 

 ever produce rot. The only decay actually caused by the Boll Worm to 

 the cotton boll occurs where the seed-cavity has been pierced and rain 

 has been enabled to enter. 



Many instances of the carnivorous propensities of the Boll Worm have 

 been met with during the past few years. We have known the larger 

 worms (and the act has been repeatedly seen by observers in the employ 

 of the Commission) to seize upon the smaller worms, biting through the 

 skin and feeding upon the juices of the body. And this has not only 

 been done in the confined breeding jars, but upon the cotton plant, in 

 open air, with an abundance of vegetable food at hand. Professor Willet, 

 as we learn from his correspondence with us, has also noticed the same 

 occurrence with these worms when feeding upon tomato, and Judge 

 Johnson has noticed.the same habit among the corn-feeding worms. 

 More interesting, however, than this, even, is the habit which the Boll 

 Worm has of occasionally preying upon the pupas of Aletia. This was 

 observed we think for the first time by Mr. Trelease while in the employ 

 of the Department of Agriculture during the summer of 1879, at Selma, 

 Ala. He says : 



Owing to its tough, integument, the pupa of Aletia seems to be freer from insect 

 attack than the larva is, yet even its hard skin does not always save it. About the 

 middle of August I first noticed what appeared to be an anomalous preparation for 

 puliation in tlie boll- worm {Helioihis armigera), for I found several full-grown larvte 

 of this species with leaves closely webbed around them, precisely as Aletia weba up 

 before changing to a pupa. An examination of one of these leaves, however, showed 

 me that the boll-worms had not webbed them about themselves, but had insinuated 

 themselves into leave* folded and preoccupied by Aletia, the latter having already 

 passed into the pupa state, and they had done this for the express purpose of feeding 

 on these pup^e. Marty cases of this sort were seen. 



Judge Johnson gives the following very interesting account of this 

 habit in his report of observations : 



Though almost omnivorous, Heliothis larvae are essentially pod borers and seed 

 eaters. They will take to anything having the appearance of a pod. This is curi- 

 ously manifest in their preference for the chrysalides of other Lepidoptera. The 

 larger worms would leave everything for the pupae of Aletia when they were plenti- 

 ful. This special omnivorous appetite was first noticed September 23, in company 

 ^'ifch Professor Jones, whilst we were experimenting in a field infested with Aletiae. 



