230 
THE ELM LEAF BEETLE 
The statement was made in 1905 that this imported insect was 
in all probability responsible for more ruined elm trees in the 
Hudson River valley than all other destructive agencies com- 
bined. Certainly the same statement could be applied with 
equal truth to the Connecticut River valley and doubtless to 
many other localities where the insect has been established. 
It is thought that the beetle was introduced into this country 
about 1834, and since that time many thousands of elms have 
been killed by its repeated attacks. While individual insects 
do not fly far, the spread of the species has been comparatively 
rapid, and its history and destructiveness is too well known to 
deserve extensive discussion. 
A few seasons ago attention was attracted to the sudden sub- 
sidence of the beetle at the New York Botanical Garden. So 
rare had it become that it was difficult to locate a single in- 
dividual. This sudden disappearance was quite naturally 
attributed to local activity in the application of sprays. In- 
quiry soon disclosed the fact that similar conditions had been 
noted in Massachusetts, New Jersey, and other parts of New York 
and by the writer’s personal observations in the Connecticut 
River valley. Each locality attributed the sudden decrease or 
complete disappearance of the insect to its own efforts in the 
use of control measures. In the Connecticut valley, however, 
the beetle disappeared from large trees which had been badly 
infested and had never been sprayed, so that its disappearance 
could not have been due entirely to artificial control but probably 
to some unfavorable natural condition or the sudden appear- 
ance of some natural enemy. 
While spending a vacation at Portland, Connecticut, in the 
summer of 1919, the writer noticed that the elm leaf beetle, 
which had been conspicuous by its absence during the four pre- 
ceding years, had reappeared in such numbers that by the end 
of July the leaves of many trees had been completely skeletonized 
and were beginning to turn brown. 
Later in the season the trees in the New York Botanical Garden 
