820 CONNECTICUT EXPERIMENT STATION REPORT, I9O7-I908. 



larger towns, on account of further injuries* by horses, by leaky 

 gas pipes in the ground, and pavements which cut off the supply 

 of moisture, many trees have died. In 1901 the writer was called 

 to Norwich, where nearly every elm had died for a distance of 

 about one and one-half miles on a prominent residential street. 

 These trees had been weakened by the constant attacks of the 

 beetle year after year, and a leaky gas main finally destroyed what 

 little vitality remained. Most of the maple trees along the street 

 survived. 



In many cases young or newly planted trees seem to be 

 especially subject to attack, and therefore should receive extra 

 attention. 



FOOD PLANTS. 



Elms constitute the only food plants known for this insect, 

 and the European species suffer more than the American ones. 

 The English elm (Ulmus campestris) and its weeping variety 

 known as the Camperdown elm are favorites of the beetle. The 

 writer has seen these trees entirely defoliated in New Haven 

 when the common white, or American elms, were uninjured. 

 The American elm is, however, the next choice, followed by the 

 Scotch elm ([/. montana), and though no variety is wholly 

 exempt from attack, the winged elm {U. data), the slippery elm 

 {U. fulva), the cork elm (C/. suberosa) and the rock elm (C/. 

 racemosa) are much less frequently attacked. 



NUMBER OF GENERATIONS. 



According to Burgess,t "in New Jersey, Professor J. B. Smith 

 has recorded only a single brood and sometimes a partial second 

 brood, while in the latitude of Washington, D. C, according to 

 the observations of Messrs. Riley, Howard and Marlatt, of the 

 Division of Entomology, two annual broods and sometimes a 

 partial third brood have been found." 



Dr. E. P. Felt, state entomologist, of Albany, N. Y., finds$ 

 two well-marked broods and a partial third brood at Albany 

 and Troy, N. Y. 



* ^5'' ?: discussion of these injuries the reader should consult Bulletin 

 131 of this station. 



tBulletin No. 4, page 17, Ohio Dept. of Agriculture, Div. of Nursery 

 and Orchard Inspection, 1905. 



t Bulletin No. 57, N. Y. State Museum, p. 14, 1902. 



