Chapter II. 



INSECTS INJURIOUS TO THE ELM. 



No shade tree is held in higher estimation than the elm. It is the 

 pride of New England and New York towns and villages, as well as 

 those of the northern, central, and middle Atlantic States. Kaltenbach 

 enumerates 107 species of insects which in Germany live at the expense 

 of the elm, while in this country we have about 80 species, the elm not 

 occurring in the Rocky Mountains or on the Pacific coast. 



The species which are the most abundant and persistent in their at- 

 tacks are the common elm-tree borer, the canker-worm, and a plant- 

 louse which disfigures the leaves by crumpling and discoloring them. 



AFFECTING THE TRUNK. 



1. The common elm-tree borer. 



Saperda tridentata Olivier. 



Order Coleoptera ; Family Cerambycid.e. 



Perforating and loosening the bark and furrowing the surface of the wood with 

 their irregular tracks, flat white lougicorn borers, changing to beetles in June and 

 July; the beetles flat, dark brown, with a longitudinal three-toothed red stripe on 

 the outer edge of each wing-cover. 



This is the most destructive borer of the elm in the Northern and 

 Eastern States, often killing the trees by the wholesale. Great num- 

 bers of the larvte of different sizes have been found boring in the inner 

 bark and also furrowing with their irregular tracks the surface of the 

 wood, the latter being, as it were, tattoed with sinuous grooves, and 

 the tree completely girdled by them in some places. The elms on 

 Boston Common have in former years been killed by this borer, and 

 valuable trees, we have been informed, have been killed by them in 

 Morristown, N. J. It has been found in all stages in the elm at Detroit, 

 Mich., by Mr. H. G. Hubbard. 



Fitch remarks that it consumes the inner bark of the slippery elm 

 ( Ulmus fulva), especially in dead and decaying trees. According to 

 him, "the beetle deposits its eggs upon the bark in June, and the young 

 larviB therefrom nearly complete their growth before winter, and soon 

 after warm weather arrives the following spring they pass into their 

 pupa state." We have found the larvse in abundance in the early 

 spring in Providence in old dead elms. 



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