27 



rather than those more ravenous like the Elm Beetle and 

 Tussock Moths, which devour much of the substance of the 

 leaf, and leave the remainder to dry up and turn a dead 

 brown. 



The early change of Pyrus arbutifolia, Sassafras, Maple, 

 Birch, Elm, Rhus, Tupelo and Ampelopsis, is largely due 

 to their agency, and in dry seasons, in dry or sandy soil, 

 these trees and shrubs are conspicuous for their bright 

 colors before the light frosts appear in the latter part of 

 September, but the change is not general, as the gray birch 

 and elm are really among the last to lose all their leaves, 

 and even many individuals of maple and tupelo retain their 

 foliage until the October frosts. 



Oak tree borers, after channeling the stem of a small 

 terminal branch for several inches, make a neat transverse 

 cut entirely across the ligneous portion, sparing only the 

 bark, by which sprays two or three feet in length hang sus- 

 pended with their unsightly, dried up, brown leaves until 

 dislodged by wind or rain. These dead branches are most 

 commonly seen on the scarlet or black oak, but are also to 

 be met with on other species, and on the elm. 



Trees transplanted in summer are [)retty sure to have 

 some of their leaves change color. As an experiment some 

 young growths of birches, pyrus arbutifolia and rhus copa- 

 lina were transplanted. The lower leaves of the birch 

 turned yellow, half of those of rhus and nearly every one of 

 pyrus became crimson. Disturbance and injury to the roots 

 was the cause. Colored leaves can easily be produced arti- 

 ficially by girdling and other methods. Many leaves when 

 changing color become red or yellow according to exposure, 

 as the tupelo, which is scarlet in the sun, yellow in the 

 shade, and orange in medium illumination. 



Several red tips of branches of Leucotho'e raceniosa, Gray, 

 Aug. 10, were due to injury : one branch was broken, 

 another split down the stem, one eaten by a worm under 

 the bark, and one was closely entwined by the tendrils of 



