24 
of Columbia it has been rather extensively infested by a plant louse 
(Siphonophora liriodendri), but although the lice occur on the leaves 
in great numbers, the general appearance of the trees has not suffered. 
There is a little galk midge which produces little black spots on the 
tulip tree leaves and disfigures them to some extent, and quite recently 
Mr. Schwarz has found that tulip scrub is affected to some extent in 
the District of Columbia by a little bark-boring beetle. 
The box elder is a singularly unfortunate choice for a shade tree in 
this climate. It is almost defoliated by the webworm, it is sought 
after by the tussock moth, and various leaf-rollers attack it as well as 
certain destructive borers, 
In the West the box-elder 
plant-bug (Leptocoris trivit- 
tatus) breeds upon it in 
enormous numbers, and not 
only damages the trees to a 
serious extent, but causes 
much further annoyance by 
entering houses for hiber- 
nation. 
The European elm is given 
a low rank, almost entirely 
on account of its annual de- 
foliation by the imported 
elm leaf-beetle. 
The honey locust and the 
black locust, while not defo- 
liated to the same extent ar 
many other trees by the web- 
worm and the tussock-moth 
caterpillar, are rendered 
very unsightly almost every 
year by the work of a leaf- 
mining Hispid beetle and of 
certain Lepidopterous leaf 
miners. They are also fre- 
quently killed by the large Lepidopterous borer, Xyleutes robiniew, and 
certain Coleopterous borers also infest them. 
From the insect standpoint, there are several fine-growing orna- 
mental trees on the grounds of the Department of Agriculture, not 
listed above, which are seldom attacked by insects. The beeches, 
hornbeams, alders, and magnolias have very few insect enemies, and 
are rarely defoliated by either of the principal leaf-eating caterpillars. 
With regard to the extreme attractiveness which the European elm 
possesses for the imported elm leaf beetle, the question is frequently 
asked whether it would not be better to cut down all European elms 



















































































Fic. 9.—Fall webworm (Hyphantria cunea). Moths and 
cocoons—natural size (original). 
