So 



Bulletin 233. 



alder sawfly also discussed in this bulletin. It " blisters " and kills the leaves 

 and thus far works almost entirely on English elms {Ulmus catnpestris), and 

 Scotch elms {Ulmus scabra or montana), including the " Camperdown " 

 variety. 



Historical. — Apparently the first and only record of this new elm pest in 

 America is the following brief note by Dr. Felt in 1898 (Bull. 17, U. S. Div. 

 of Ent., p. 21 ; 14th Rept. of State Ent., 237) : "An elm leaf-miner. 

 This insect has been unusually destructive in Albany and Troy the present 

 season. For the past three years the Camperdown elms in Washington Park, 

 Albany, have suffered rather severely from this species. The present season 



Fig. 23. — A European elm case-hearer at ivork on an elm-leaf from Brooklyn 

 Parks. A\itural size. 



the miner not only seriously injured the Camperdown elms but extended its 

 ravages to the English, Scotch and American species. From half to two- 

 thirds of the leaves on certain English elms in Troy were nearly destroyed by 

 this insect, and many others presented a sorry appearance on account of the 

 numerous mines." 



In July, 1899, I received from New Brighton, N. Y., "blistered "leaves 

 from a Camperdown elm, which had been nearly defoliated. Only the dried 

 remains of a few larvae remained in the " blisters " and it was not until 1901 

 that I got living specimens of the depredator. It was then found that a group 

 of Scotch elms on the Cornell University campus had been seriously infested 

 for several years by a similar insect. The adult insect was not found and 

 attempts to breed it in 1903 failed, and it was not until May 27th, 1904, that 

 I first saw the adult insect which was then present on the elm leaves in large 

 numbers. The pest is evidently the common elm sawfly leaf-miner of Europe, 



