122 



Bulletin 233. 



I must now add to this list another serious insect enemy which has 

 followed the European elms to America. This new elm pest is a near 

 relative of the alder sawlly also discussed in this bulletin. It " blisters " 

 and kills the leaves and thus far works almost entirely on English elms 

 (Uluius campcstris), and Scotch elms {Uhniis scahra or montana) , in- 

 cluding 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. 



Fig. 23. — A Etiropcan clin casc-hcarcr at work on an chn-lcaf fron 

 Brooklyn parks. Natural size. 



The ])rcsent season the miner not only seriously injured the Camperdown 

 elms l)ut extended its ravages to the English, Scotch and American 

 species. From half lo 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, wdiich had been nearly defoliated. Only 

 the dried remains of a few larva; 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 



