6 BULLETIN 276, TJ. S. DEPARTMENT OF AGRICULTURE. 



IN AMERICA. 



Dr. Cyrus Thomas was the first to observe and record this species 

 from America (1878, 1879). The authenticity of this record has been, 

 doubted by most writers, but we have examined the specimens used 

 by Thomas in drawing up his description (Davis, 1913) and find them 

 to be the MacrosipJium pisi of Kaltenbach. Thomas's specimens were 

 collected in Illinois in 1878, which is indicative of its introduction 

 into America some years previous, possibly as much as 10 or 15 years 

 before. Subsequently and previous to 1899, pisi was reported by 

 Oestlund (1886), Smith (1890), and Williams (1891). 



MacrosipJium pisi, therefore, was introduced into America fully 20 

 years previous to its ajmearance in serious numbers and here we have 

 a case analogous to that of the gipsy moth, which was present in this 

 country for about 25 years before it became a pest (Chittenden, 

 1909a). 



Although the losses attributed to this aphidid have been largely to 

 garden peas, still certain other crops have been much injured by it, 

 the actual damage, however, never being apparent as in the case of 

 the garden pea. Among other crops field peas are frequently injured 

 by pisi. As early as 1900 Dr. Chittenden (1900b) reported injury to 

 this crop, grown for hay, in Virginia. Mr. G. G. Ainslie records the 

 total destruction of a plat of Canadian field peas at Nashville, Tenn., 

 as early as February 17, in 1911. 



The first positive record of injuries to clover hi America by this 

 plant louse was noted by Mr. W. G. Johnson, who wrote in 1900 that 

 "hundreds of acres of red clover have been destroyed by it [1/. 

 pisi]. In one instance, reported to me June 13, 1900, Mr. C. Silas 

 Thomas, of Lauder, Frederick County, Md., stated that the pest had 

 almost entirely ruined 65 acres of red clover. Many other cases 

 of a similar nature were reported or observed by us." Dr. E. D. 

 Sanderson (1900g) reports the occurrence of a plant-louse, presumably 

 this species, which occurred in injurious numbers on crimson clover 

 as early as 1890. In the same paper Sanderson says: 



One of our best farmers, Mr. Frank Bancroft, of Camden, Del., tells me that he has 

 seen what he judges to be the same louse on crimson clover for at least six or seven 

 years [that is, about as early as 1893]. 



In 1900 Prof. F. M. Webster (1900) observed this insect in abun- 

 dance on red clover at Woostcr, Ohio. Dr. J. W. Folsom (1909) 

 reports injury to red clover in the following words: 



In 1903 the louse killed an immense amount of red clover and weakened much m< »re 

 in Dekalb County [Illinois]. * * * I found on the farm of Mr. A. E. Myers, at 

 Millbrook, August 19, 80 acres of dead clover roots in one field. Not one root in a 

 thousand showed any signs of life, and on the ground were thousands of the casl skins 

 of the aphid. At culling the lice had been such a nuisance thai the men objected to 

 handling the crop. After cutting the clover never revived. In neighboring fields 



