46 



■dying state, and nearly all of them were more or less af- 

 fected with disease or premature decay. Their bark was 

 perforated, to the height of thirty feet from the ground, 

 with numerous holes, through which insects had escaped ; 

 and large pieces had become so loose, by the undermin- 

 iag of the grubs, as to yield to slight eti'orts, and come off 

 in flakes." 



Somewhat later Dr. Asa Fitch observed the same in- 

 spect about diseased elms in New York. The species at- 

 tacked in this case was the slippery elm (Ulmus fulva) 

 and he states that whenever portions of the bark of this 

 tree has been stripped off for medicinal purposes "the re- 

 maining bark immediately becomes filled with these 

 worms, by which all its inner layers are consumed in a 

 few months and changed to worm-dust." 



More recently still an outbreak of the pest occurred in 

 Illinois where I had an opportunity to observe it. Its 

 work in this State was not confined to large trees, young 

 ■ones twenty feet or less in height being also attacked- 

 At the time of the outbreak Prof. Forbes the, State 

 Entomologist wrote : "The difficulty with the trees com- 

 monly commences to declare itself from the middle of 

 summer to autumn, when the leaves, first upon the ter- 

 minal twigs and then upon the larger branches, are seen 

 to stop their growth, change their color and ultimately 

 to fall." The first attack was sometimes made on the 

 upper branches these being killed while the remainder 

 continued to put forth new leaves until they were in 

 vaded. 



The grub which mines the bark measures when fully- 

 grown and extended about one inch in length, is 

 cylindrical in general shaps, but becomes somewhat en- 

 larged and flattened at the front end, like the round- 

 headed appletree borer The head is immersed in the 

 succeeding division of the body and hence seems smaller 



