BOLL-WORMS VS. COTTON- WORMS. 179 



Lepidopterous predatory insects upon record. These are Euclemensia 

 Bassettella, Clemens, which feeds upon the eggs of an oak-bark louse,* 

 Semasia prunivora, Walsh, which feeds upon the lice of the coxcomb 

 elm-gall (Colopha ulmicola, Itiley), and Dakruma coccidivora, Comstock, 

 which preys upon the eggs and young of cottony maple scale insect t 

 (Pulvinaria innumerabilis, Rath von). 



In spite of this fact, many Lepidopterous larvae when placed in con- 

 finement will destroy one another, and facts have developed which war- 

 rant us in putting the boll-worm down as an occasional enemy of the 

 cotton-worm. 



THE BOLL-WORM (HeliotUs armigera, Hiibn.). Although the boll- 

 worm may be put down as almost omnivorous, and although it becomes 

 cannibalistic in confinement (so much so that in breeding but one can 

 be kept in the same cage, and in sending through the mails one box had 

 to be allowed for each individual), we hardly expected to see it develop 

 any characteristic which could be called beneficial j yet, according to 

 the observations of Mr. Trelease, it seems to have done so. Mr. Trelease 

 says in his report : 



Owing to its tough integument, the pupa of Aleiia 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 

 pupation in the boll-worm (Hdiothis armiyera), for I found several full-grown larvae 

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

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

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

 selves into leaves 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 pupae ; many cases of this sort ivere seen. 



So plain a case as this requires no comment. It is of interest scien- 

 tifically but its practical bearings are slight. Earlier in his report, bear- 

 ing on this same point, Mr Trelease says : 



No Lepidopterous enemies of Aletia larvae were observed by myself, but Dr. Lock- 

 wood of Carlowville, Ala., says that a number of years ago, he saw a large green 

 larva devouring numbers of cotton-caterpillars. From what we know of the habit of 

 the boll-worm (Heliothis armiyera) it seems not at all unlikely that these larvae may 

 have belonged to that species. 



It will also be interesting in this connection to state that the boll- 

 worms have been observed to kill one another on the plants, in open 

 air, and perfectly unmolested, as will be shown in Part II. 



As bearing upon this point of other Lepidopterous larvae attacking 

 the cotton-worm, we quote the following sentence from Dr. Ander- 

 son's report: "I have never seen the worm attacked by any other in- 

 sect than t\\Q grass-worm and then only when brought in contact." Con- 

 cerning this same insect, Lapliygma fruyiperda, of Smith & Abbot 



* Proc. Ent. Soc., Phila., ii, p. 423. 

 t North American Entomologist, i, p. 25, October, 1879, 



