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In the Spring and early Summer of 1890, this aphis was again 

 in the orchards wherever I went, and in much larger numbers than 

 the year before. It was also sent to me, or reported to me, from 

 southern New Jersey, Virginia, the west shore of the Chesapeake in 

 Maryland, and from southern parts of the Chesapeake and Delaware 

 peninsula, which I was unable to visit. I could not, however, learn 

 of its presence in any part of the extreme South, although I made 

 diligent inquiry of many peach growers, and supplemented this by 

 personal observation during June and July in the orchards and nur- 

 series of middle Georgia. In Delaware and Maryland, and parts 

 of New Jersey and Virginia, this aphis was reported everywhere to 

 be unusually prevalent and destructive. In April, when the leaf 

 buds were pushing, I saw them clustered upon so many shoot-axes, 

 and so compactly, as to kill young trees, and even very considerable 

 branches upon older trees. They were especially destructive to 

 nursery trees and to orchards just planted. I saw one nursery in 

 which at least 100,000 trees had been killed outright in two or three 

 weeks' time. I also heard of half a dozen large nurseries which 

 were entirely destroyed or very seriously affected, and of orchard- 

 ists who will be compelled to replant hundreds of trees. 



In the upper part of Maryland and Delaware, these aphides 

 were less destructive than on the sandy lands of Sussex, Caroline, 

 Calvert, and other southern counties. Toward the end of May they 

 had almost disappeared, owing in part, at least, to the attacks of 

 Coccinellidae and other enemies. By mid-Summer they had disap- 

 peared completely, but were to be found on the roots as usual. 



There can be no doubt, I think, as to the identity of the aerial 

 • and subterranean forms. They are alike in every important par- 

 ticular, — in structure as well as in color. Indeed, it would puzzle 

 any one to tell whether a given specimen came from above ground 

 or below. I have found colonies of identical appearance, macro- 

 scopically and microscopically, on outer limbs, on short spurs of 

 main branches, on the trunk near the earth, on the collar just be- 

 neath the surface, and on all parts of the root system. Moreover, 

 there are biological as well as morphological reasons for believing 

 the two forms identical. 



This aphis is visited by several ants, and is specially fostered by 

 Las/us claviger Roger, a yellow species. These ants live in the 

 earth of peach orchards, and I have seen them carry the under- 

 ground form from place to place when the roots have been disturbed. 

 If they do this when the aphides are molested, they undoubtedly do 

 it at other times; and, if such arc their habits underground, very 



