64 OUR SHADE TREES AND THEIR INSECT DEFOLIATORS. 
fluences soon begin their work of causing decay between the bark and 
the solid wood; and this is but the forerunner of greater injury by in: 
sects which are attracted to the spot, and which, though hidden mean- 
while from view, soon carry the destruction from the injured to the non- 
injured parts.” 
There is, in fact, more danger that our trees in future (especially the 
Soft Maple) will begin to fall and perish from the ravages of Borers, 
as & result of reckless pruning, than that they will ever be seriously 
or permanently injured by leaf-eaters. These last, as we have seen, 
may be overcome, but the Borers are not only more deadly but more 
difficult to manage. 
TREES WHICH ARE UNINJURED. 
I have already indicated a few of the trees which are most subject to 
injury from this Web-worm. There is also quite a list of trees which 
are either very little affected or are never attacked, and in thts connec- 
tion it may be well to mention a few of these which are, not only on this 
account but in every other way, desirable for shade trees and should 
be strongly urged upon the Parking Commissioners as substitutes for 
those, like the Box Elders, which are so seriously affected. In this list 
of desirable trees which have immunity I would mention: 
Tulip tree (Liriodendron tulipifera L.). 
Sweet Gum (Liquidambar styraciflua L.). 
Sweet Buckeye (dsculus flava, Ait). 
Ohio Buckeye (dsculus glabra, Willd.). 
The Maples (Acer rubrum, A. saccharinum, A. pseudoplatanus, and 
A. dasycarpum). 
Honey Locust (Gleditschia triacanthus L.). 
Kentucky Coffee Tree (Gymnocladus canadensis, Lamb). 
Sour Gum (Nyssa multiflora, Wangerb.). 
Beech (Fagus ferruginea, Ait). 
Yews (Taxus spec.). 
GOOD AND BAD EFFECTS OF OUR TREES. 
The beauty of Washington is very greatly enhanced by its shade 
trees, and the Parking Commission deserve very great credit for the 
gigantic work they have carried out in the last fifteen years. But while 
these trees are and ought to bein the future an unending source of 
pleasure and healthfulness, yet here, as is so often the case, the good 
has some corresponding evil. This last, however, may be easily avoided. 
We hear much of malarial troubles in Washington, and the Potomac 
flats come in for nearly the entire blame. During the month of Oc- 
tober our. streets are constantly covered with fallen leaves from our 
shade trees, eddying and whirling about and carried by every heavy 
