34 



much the same manner as the eggs of the potato beetle, an allied 

 insect. The young larvse emerge in about one week (from late in 

 May to the middle of June) and attack the under surface of the 

 leaves, gnawing away the epidermis and causing the leaves to 

 turn brown. From two to three weeks are required for the com- 

 pletion of the larval stage, at the end of which period they are 

 about one-half an inch in length, of a yellowish color, with a dark 

 brown or black stripe on either side. They then descend to the 

 rough bark of the tree or to the ground and transform to pupae. 

 From five to ten days are spent in the pupal stage, varying accord- 

 ing to the temperature, when the mature beetles emerge, feed, 

 pair, and lay eggs for a second brood which matures in the late 

 summer. The beetle is from one-fourth to three-eighths of an 

 inch in length, pale yellow with a black stripe on the outer part 

 of each wing-cover. I have not been able to observe the trans- 

 formations of the second brood, but there can be no doubt that 

 there is such a brood in this State, since on July 1 of the present 

 year, pupa? were found at Springfield, and at the present writing, 

 July 8, many beetles are emerging. 



Food Plants. 



This insect feeds upon both the European and the American 

 elm, naturally preferring the former. In many cases, notably at 

 Northampton, where European elms stand in close proximity to 

 American elms, the former are badly injured while the latter are 

 practically unharmed. Where the European elm is not available, 

 however, the American species is readily attacked and severely 

 injured. At Groton, last summer, numbers of large American 

 elms were so severely injured that they were as brown as if 

 scorched by fire. At Springfield several American elms that were 

 stripped three years in succession are now in a dying condition. 

 Dr. Felt states that the Scotch elm also suffers seriously from the 

 attacks of this insect. 



Nature of the Damage. — The first injury to the tree is caused 

 by the attack of beetles on the leaves. Later the larvse destroy 

 the epidermis, the leaves turn brown, die and fall, and the tree is 

 left bare until a second crop of leaves is thrown out. Frequently 

 these leaves are in turn destroyed by the later brood of larvse. 

 The effect "upon the tree is shown by the gradual death of the 

 smaller branches, and of the entire tree in cases of severe and con- 

 tinued stripping. City trees through ignorant or careless treat- 

 ment commonly suffer from lack of food and water supply due to 

 the cutting off of roots to make room for curbings and water and 



