10 
branches to the crotch and transform unprotected in the hollow of the 
crotch. 
The larva is elongate, reaching when full grown (fig. 3, e) half an 
inch in length. When first hatched it is nearly black; as it increases 
in size it becomes, with each shedding of the skin, more distinctly 
marked with yellow, and when mature the yellow predominates, 
oceurring as a broad dorsal stripe and two lateral stripes. 
The difference between the early work of the beetles and the later 
work of the larve is recognized at a glance. The beetles eat entirely 
through the leaves and make complete, irregular holes, while the larve 
simply eat the parenchyma from below, skeletonizing the leaf. 
The time occupied in egg laying is long, and it thus happens that at 
the time when full-grown larvee, and even pup, are to be found there 
are also upon the leaves freshly laid eggs. 
In Washington there are invariably two generations annually, the 
beetles developed from the eggs laid by the overwintered beetles them- 
selves laying their eggs in July. The adults issuing from these eggs 
make their appearance in August. Farther north, at New Brunswick, 
N. J., and in the Connecticut cities, it may be said that there is nor- 
mally a complete first generation and an incomplete second generation. 
The proper food of the larvie is the rather young and tender leaves. 
If the work of the first generation has not been complete, and the trees 
have not been so nearly defoliated as to necessitate the sending out of 
fresh leaves, or if a period of drought ensues after defoliation and pre- 
vents the putting out of a second crop of leaves, the beetles of the first 
generation do not lay eggs, but after flying about for a time seek winter 
quarters. This may occur as early as the middle of July. Where, 
however, defoliation has been complete and has been followed by a 
period of sufficient moisture to enable a tree to put out a fresh crop of 
leaves, the beetles of the first generation will lay their eggs and a sec- 
ond generation of larvie will develop upon this comparatively tender 
foliage. Where similar conditions prevail in Washington and _ its 
vicinity, a third generation of larve may develop, though small in 
numbers, but the writer is convinced that even in Washington late- 
developing beetles of the first generation may hibernate. 
Remedies.—The only thoroughly satisfactory safeguard against this 
insect consists in spraying the trees with an arsenical solution. The 
only other remedy which is worthy of mention is the destruction of the 
larvee at the surface of the ground before or after they transform to 
pupe. The latter remedy, however, is not complete, and even where 
it is carefully carried out for every tree in a city it will do no more than 
reduce the numbers of the insects by perhaps two-thirds. 
Ten years ago a proposal to spray the enormous elms which are to 
be found in many Northern towns would have been received with 
ridicule, but of recent years the practicability of the plan has so fre- 
quently been demonstrated that there is no hesitancy in commending 
