182 REPORT UPON COTTON INSECTS. 



cotton-worm. Mr. Glover, in the Agricultural Eeport for 1867, p. 60, 

 says : 



The eggs of the cotton-moth are frequently destroyed by several species of small 

 ants, which are said to bite the eggs open when first deposited, and to abstract the 

 substance. Many caterpillars, especially if weak or somewhat disabled, fall victims 

 to the voracity of the restless myriads of ants always abounding in the fields and feed- 

 ing upon the honey-dew secreted by the cotton-louse or aphis, and the bodies of such 

 insects as they can overcome. 



Dr. Phares, however, takes a very different view of the ant question, 

 as advanced in the following quotation in his 1869 essay : * 



Last year on a farm in Louisiana, as already mentioned, the caterpillar commenced 

 its work as early as May, and continued iintil frost terminated its labor; yet one gen- 

 eration succeeded another so slowly and in such small numbers that the cotton was 

 scarcely injured; while on other places where the destroyer appeared later the cotton 

 plants were so early and completely destroyed as not to mature sufficient seed to plant 

 another crop. Why this difference? The owner of the farm mentioned, as well as 

 others, alleged that the ants being very numerous, earned off and destroyed the eggs and 

 young caterpillars. The ants, it is true, swarmed in unwonted numbers in the cotton 

 fields, as they did also in corn-fields, potato-patches, gardens, orchards, and forests. 

 But on other places where there were plenty of ants constantly infesting the plant the 

 caterpillar wholly destroyed the cotton. Again, in some fields the cotton was completely 

 stripped, as we often see, up to a definite line on one side, while not a leaf was touched 

 on the other side of this lino. This occurs even where the same rows cross this line, 

 one portion of the row being stripped and the other unharmed, although there were 

 plenty of ants on both sides of this mysterious line, established by the caterpillars 

 themselves. And again, on inquiry, I have never found any one who has seen the anlseat' 

 ing or carrying off either the eggs or young caterpillars. 



Here, then, it appears, is a total want of facts, and the ant theory is so far without a 

 shadow of foundation on observed facts. 



The ants collected in the cotton fields were referred to the Eev. H. C. 

 McCook, of Philadelphia, and he has kindly prepard the following report 

 upon them : 



FORMICABIAE. 



The specimens of ants sent are of seven species, all of which are represented as in 

 attendance upon or actually engaged in the destruction of the cotton-worm. These 

 species represent two of the three families of Formicariae, viz, Formicidac and Myrini- 

 cidae. Of these, two were too much broken to allow specific determination. 



The relation of ants to the Iarva3 of Lepidopterous insects has recently attracted the 

 attention of students. During the summer of 1877 I observed several workers of 

 .Formica fusca in friendly attendance upon a small green grub which proved to be the 

 larva of Lycaena pseudargiolus, a butterfly.* About the same time Mr. W. H. Ed- 

 wards, widely known as a student of Lepidoptera, observed the same behavior, and 

 during the following year pursued his investigations further. The results he has 

 given in an interesting communication to the Canadian Entomologist. He showed 

 that the ants attend the larvae with the same purpose as that which attracts them to 

 the Aphides, viz, to feed upon a sweet excretion which issues from the insect. In the 

 Aphis this is probably excrementitious. In the larva the sweet exudation is a secre- 



* Rural Carolinian, 1869, p. (190. 



"Mound-making Ants of the Alleghenies, Trans Am. Ento. Soc., 1877, p. 290, and 

 John A. Black, Philadelphia. 



