EEPORT OF THE ENTOMOLOGIST. 297 



{Hymen&pt., fam. SeoUadae) ; Pelopoem cceruleus, Linn. {fam. Sphegidae) ; 

 Folistes beUicosa, Cress. ; Vespa Carolina, Drury. 



Ants {Rymcnopt., family Formicariae). — The predaceoiis insects ft-om 

 which the cotton-worm sufiers the most are, without doubt, the ants. 

 These insects, from their warhke habits and the enormous numbers in 

 which they occur, seem peculiarly fitted to hold in check even so dan- 

 gerous an enemy as the cotton-worm. The efficacy of ants as cotton- 

 worm destroyers has been noticed by but few writers upon the cotton- 

 worm, and indeed there are some who insist that they never attack it. 

 During my own stay at the South I never was able to see ants attack a 

 worm upon the plant. Upon the ground, however, the case was far dif- 

 ferent. There I repeatedly saw ants attack and destroy cotton-worms. 



In dry weather the ground cracks to a great extent. The ants make 

 their nest in these cracks, and while excavating them cover the surface 

 of the ground with fine particles of earth. It is difficult for cotton- worms 

 to crawl over such places ; for when they seize hold of the loose parti- 

 cles of earth by their pro-legs, they are unable to balance themselves, 

 roll over upon their sides, and, if the earth be hot, speedily perish. In 

 this indirect way the ants cause the destruction of millions of the worms. 



Several of our correspondents stated that ants were known to prey 

 upon the cotton-worm j and Mr. Trelease reported as follows : 



From their great ntunTbers and indefatigable industry, ants are probably among tbe 

 most important of the enemies of the cotton-caterpillar. Individuals of many speciea 

 swarm everywhere on the cotton plants, to which they are attracted night and day by 

 Aphides and nectar. On many cotton leaves there are places where some larva has 

 eaten the parenchyma of the lower surface, but the most careful search fails to dis- 

 cover the larva. Though not invariably so, these places are often eaten by very young 

 lai-vae of Aletia, and as these are not to be found, it looks as though they had been re- 

 moved by some enemy, probably ants, though I have never seen ants attack very small 

 caterpillars. In July a number of caterpillars were collected in the bottom-land, to 

 which they were principally confined at that time, and placed on cotton growing iu 

 dry, sandy soil, care being taken to see that there were no ants on this cotton when 

 the larva was placed on it, for my insects iu breeding-jars in the house had suffered 

 so much from the depredations of ants that I was always afraid of their attacking 

 larvae that I M'anted to study in the field ; and these particular caterpillars had been 

 removed to the cotton indicated because I Avished to make observations on their habits, 

 and wanted them as near the house as might be, while at that time the only larvae to 

 be found in numbers were aboiit a mile from where I was living. Within two hoiua 

 of the time of placing them on this cotton, each of these larvae was found by several 

 ants, and these soon collected numbers of theu" fellows, whose combined attacks so 

 worried the larvae that they thi-ew themselves from the plants and were soon killed 

 and carried off' by their small but persistent enemies. On several other occasions 

 partly growm caterpillars were killed and carried otf iu this way by this species and a 

 red ant, yet I never saw ants attack them on the plant excepting when I had thus 

 placed them on ridge-cotton for purposes of study ; but when creeping over the ground, 

 as they do after eating up the foliage of the plant on which they were born, if not fall 

 grown, hundreds of caterpillars were attacked by these ants and killed. I have never 

 seen more than one species of ant attacking any individual caterpillar, either on tho 

 plant or on the ground. 



Mr. Trelease further remarks, in speaking of the enemies of the 

 chrysalis : 



In the latter part of .July several Aleiia, just about to pupate, were taken from the 

 swamp where they were found, and with leaves webbed about them they were trans- 

 ferred to cotton on dry soil near the house, where they were tied by their leaves to 

 the petioles of this cotton ; my object in placing them there being to determine the 

 length of the pupa state. The" same day they shed their last lai-va skins and this left 

 them in an almost defenseless condition till the pupa skin should become firm and 

 tough. About iwenty-fotir hours after this moult they were again visited, and were 

 foimd covered with red ants, which had killed and partly eaten them all, though they 

 were on different plants, and care was taken to see that there were uo ants on the cot- 

 ton when the larvae were placed there.* 



*The ants collected iu the cotton fields were referred to the Eev. H. C. McCook, who 

 prepared a report upou them which is embodied in our special report. 



